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441 Cards in this Set
- Front
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endoparasites
|
helminths (nematodes, cestodes, trematodes)
protozoa (mastigophora, apicomplexa) |
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nematodes
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roundworms
|
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nematodes (direct lifecycle - generalized)
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L1 - L3 in environment (eg. soil)
L3 ingested "L5" = immature adult moults between ea. stage |
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nematodes (indirect lifecycle - generalized)
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L1 ingested by IMH(eg. mosquito)
L3 transmitted to DH |
|
nematode larval migration
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hepato-tracheal:
from gut to liver (portal) to heart via hepatic vein and PVC to lung via pulmonary artery to gut (coughed and swallowed) |
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arrested larval development (ALD)
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if in immune adult, goes into tissues and arrests to avoid death by immune system; passed to offspring and comes out of arrest;
|
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pre-patent period (PPP)
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time from infection (eggs/larvae) to mature egg laying adults
|
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Nematode superfamilies
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Ascaridoidea (Toxocara, Ascaris)
Strongyloidea (Strongylus, Ancylostoma) Trichostrongyles (Trichostrongylus, Ostertagia, Haemonchus) Trichuroidea (Trichuris, Capilleria, Trichinella) Filariodea (Dirofilaria, Onchocerca, Parfilaria) |
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Ascarids (species)
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Toxocara (canis, cati)
Ascaris (suum, lumbricoides) |
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Ascarids (general characteristics)
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large white worms
direct life cycle L2/L3 is infective (oral) small intestine (SI) |
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Trichostrongyle species (nematode)
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Trichostrongylus
Ostertagia Dictyocaulus Haemonchus |
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Strongyloidea specia (nematode)
|
Strongylus
Ancylostoma Syngamus |
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Trichuroidea species (nematode)
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Trichuris
Capillaria Trichinella |
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Filariodea species (nematode)
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Dirofilaria
Onchocerca Parafilaria |
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nematode head (morphological features)
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large or small buccal capsule
leaf crowns present or absent teeth present or absent |
|
nematode tail (male - features vary between species)
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spicules
bursa rays caudal papillae caudal alae precloacal sucker |
|
nematode tail (female - features vary between species)
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vulval (cloacal) flap
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nematode eggs (morphology)
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-Trichostrongyle - thin, oval shell
-Ascarid - thick, pitted shell -Trichuris - barrel shaped, smooth shell; plug-like operculum (both poles) -Oxyuris - ovoid, slightly flattend; mucoid plug (1 end) |
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parasitic gastroenteritis (PGE)
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generic term for disease caused by parasitic nematodes in gastro-intestinal tract; usually young, grazing stock
|
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nematode genera (bovine abomasum)
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Ostertagia (Trichostrongyloidea)
Trichostrongylus (Trichostrongyloidea) Haemonchus (Trichostrongyloidea) |
|
nematode genera (bovine SI)
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Cooperia (Trichostrongyloidea)
Nematodirus (Trichostrongyloidea) Trichostrongylus (Trichostrongyloidea) Bunostomum Toxicara (Ascarid) |
|
nematode genera (bovine LI)
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Oesophagostomum
Trichuris (Trichuroidea) |
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Trichostrongyloidea (general)
|
-most important in grazing ruminants
-direct life cycle -L3 is infective -PPP ~21 days -mainly GI nematodes |
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Ostertagia spp.
|
Trichostrongyloidea:
***Ostertagia ostertagi Ostertagia leptospicularis |
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Ostertagia ostertagi (life cycle)
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direct life cycle
PPP = 21 days adult in abomasum eggs hatch in faeces L3 ingested L3 penetrate abomasal gland L4 can arrest |
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ostertagiosis (pathogenesis)
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1. hypoproteinaemia - rupture of intracellular jxns and leakage of plasma proteins into lumen
2. elevated plasma pepsinogen - parietal cell distruction (decreased HCl and increased pH so pepsinogen not converted to pepsin) 3. bacterial overgrowth - parietal cell distruction cause pH increase |
|
ostertagiosis (pathology)
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hyperplasia of gastric mucosa
'Morrocco leather' appearance putrid smell of abomasal contents (bacterial overgrowth) nodules on abomasum large # of asult worms (1cm, reddigh) |
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ostertagiosis (clinical forms)
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Type I - grazing calves (July - October); larvae acquired from pasture 2-3 weeks earlier
Type II - housed yearlings (March - May); due to maturation of inhibited larvae from pasture during previous autumn |
|
ostertagiosis (Type I clinical signs)
|
profuse watery diarrhea (bright green)
weight loss occasional submandibular oedema (hypoalbuminaemia) morbidity high / mortality low |
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ostertagiosis (Type II clinical signs)
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intermittent diarrhea (not always)
submandibular oedema (hypoalbuminaemia) weight loss +/- moderate anaemia anorexia and increased thirst morbidity low / mortality high |
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ostertagiosis (diagnosis)
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clinical picture & grazing history
diagnosis on herd (not individual) faecal egg counts (FECs) serum pepsinogen (plama gastrin) (serum antibody) |
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fecal egg counts (FECs)
|
-Cannot discriminate between trichostrongyle eggs (xcept Nematodirus)
-There is NOT a linear relationship between FEC and parasite burden -Low FEC from individual (or small group) does NOT rule out diagnosis of PGE |
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serum pepsinogen (diagnostic)
|
-specific for abomasal parasatism (ie. ostertagia)
-useful in calves (less reliable for older animals) -useful indicator of parasite burden at end of grazing season |
|
serum antibodies (diagnostic)
|
-ELISAs for parasite antibody (research)
-good measure of exposure -not commercially available |
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Ostertagia (immunity)
|
-slow to develop
-takes at least 1 grazing season -2nd season calves and adults generally immune -immune animals still carry burdens (arrested L4) |
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ostertagiosis (Type I epidemiology)
|
-development of egg to L3 is temperature dependent
-development in June is slower than July |
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ostertagiosis (Type I epidemiology)
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April/May - calves ingest overwintered L3 (patent infection established but no clinical disease)
May/July - 1st gen of adult parasites produce eggs (contaminate pasture) July/Aug - large # of L3 on pasture ingested by calves |
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ostertagiosis (Type II predisposing factors)
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Ingestion of many L3 delayed to autum caused by:
1. grazing mgmt - moving animals to contaminated pasture late in season 2. climate - dry summer delay emergence of larvae from fecal pats |
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ostertagiosis (beef herds)
|
-uncommon in spring calving herds b/c not weaned until autumn; little pasture contamination during early season
-more common in autumn calving herds b/c weaned in spring (epidemiology similar to dairy calves) |
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Trichostrongylus axei (cattle)
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-abomasum
-very small (<1cm) -cattle, sheep, goat, horse -rarely primary pathogen (UK) -part of PGE mixed infection -L3 very resistant |
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Haemonchus
|
-abomasum
-blood feeding -'barber's pole' worm -causes anemia -not important in cattle (H. placei) -important in sheep (H. contortus) |
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Cooperia spp. (cattle)
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C. oncophora - temperate (UK), mild pathogen, PGE
C. punctata - tropical (more pathogenic) C. pectinata - tropical (more pathogenic) |
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Cooperia oncophora
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-common in UK (temperate)
-contributes to PGE (mixed) -parasitic stages develop on SI mucosa -mild pathogen (inappetence and reduced weight gain) -epidemiology similar to O. osteragi |
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Cooperia oncophora (anthelmintics)
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cattle parasite most commonly implicated in anthelmintic resistance (Ivermectin in UK)
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Trichostrongylus colubriformis (cattle)
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small intestine
<1cm can also infect sheep/goats rarely primary pathogen (PGE in UK) life cycle & epidemiolgy same as T. axei |
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Nematodirus spp. (cattle)
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N. helvetianus (part of mixed PGE)
N. battus - more important in sheep N. spathiger - more important in sheep |
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Bunostomum phlebotomum (cattle)
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Srongyloidea
small intestine cattle hookworm (sucks blood) adult 1-3cm with hooked anterior |
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Bunostomum phlebotomum (life cycle)
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-typical for hookworm - percutaneous route with pulmonary migration (oral route no pulmonary migration)
-PPP = 6 weeks (percutaneous) -needs warm/wet conditions -mainly problem in tropics |
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Bunostomum (identification)
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Gross - 1-3cm stout worm
Micro - large buccal capsule (cutting plat3es along top) |
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Trichosrongylus (identification)
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Gross - 1cm thin, straight
Micro - head (excretory notch), male tail (stepped spicules), female tail (colubriformis thin & tapered) |
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Cooperia (identification)
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Gross - 1cm (kink in female)
Micro - head (small cephalic vesicle), male tail (spicule expanded in middle), female tail (oncophora thin & tapered) |
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Nematodirus (identification)
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Gross - 1.5-3cm cotton wool appearance
Micro - head (prominent cephalic vescicle), male tail (long, thin fused spicules), femle tail (battus tapered; others truncate with small spine) |
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Haemonchus (identification)
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Gross - 2-3cm easily visible
Micro - head (tapered), male tail (barbed spicules), female tail (large vulvar flap w/ 100 eggs in uterus) |
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Ostertagia (identification)
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Gross - 0.8-1cm visible
Micro - head (tapered), male tail (long spicules; ostertagi thin picules branched at bottom), female tail (medium vulvar flap w/ 50 eggs in uterus) |
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Trichostrongylus axei (identification)
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Gross - 0.5-0.7cm barely visible
Micro - head (excretory notch), male tail (spicules unequal length), female tail (no vulvar flap w/ 5-7 eggs pole to pole in uterus) |
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GI nematodes of sheep
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Ostertagia - abomasum(PGE)
Trichostrongylus - SI(PGE) Nematodirus battus - SI Haemochus - abomasum |
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ostertagiosis (ovine)
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Type I - common
Type II - reemergence of inhibited larvae (not as common but more severe) |
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ostertagiosis (ovine clinical signs)
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-weight loss / failure to gain weight
-intermittent diarrhea (less than bovine) -appetite loss |
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ostertagiosis (ovine diagnosis)
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-clinical signs
-mainly disease of lambs -end of grazing season -fecal egg counts |
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ostertagiosis (ovine immunity)
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-slow to develop
-worm burden & fecal egg output low in adult except during periparturient period (Type II); biggest diff. from cattle |
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ostertagiosis (ovine periparturient rise)
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periparturient rise in fecal egg output (2-6 weeks after lambing) due to:
1. increased overwintered larvae from pasture 2. inhibited L4 reactivating and developing 3. female worms have increased fecundity NB: occurs in cattle but really phenomena of sheep |
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ostertagiosis (ovine Type I epedemiology)
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build up of L3s on pasture from July-Oct (like cattle):
-eggs passed by ewes during periparturient rise (major diff from cattle - must treat ewes) -eggs passed by lambs from 1st gen parasites established from overwintered larvae (also impt) |
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Haemonchus spp. (sheep)
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H. contortus (main)
H. similis (more in tropics) H. placei (more in tropics) |
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Haemonchus contortus (ovine)
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-largest parasite in omasum
-sucks blood (pathology due to this) -'barber's pole' worm (GI tract wraps around) -causes haemorrhagic anaemia (5000 adult worms can cause 250ml blood loss per day) |
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Haemonchus contortus (life cycle)
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-typical trichostrongylid
-best adapted to tropical climates (warm & moist) -development of L1-L3 rapid (in ideal conditions) |
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Haemonchus contortus (ovine immunity)
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ewes remain susceptible
|
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haemonchosis (ovine pathogenesis)
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hyperacute (up to 30k adults):
-sudden death due to severe hemorrhagic gastritis Acute (2k - 20k adults): -clinical signs ~2wks post infection -regenerative anaemia followed several weeks later by non-generative anaemia chronic (several hundred adults): -weight loss, weakness, inappetence (+/- anaemia) |
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haemonchosis (ovine clinical signs)
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-hyperacute: sudden death
-acute: anaemia, submandibular oedema, ascites, dark faeces, dropping wool, inappetence -chronic: weight loss, weakness, inappetence -NB: diarrhea not usually a feature (unlike most other parasites) |
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haemonchosis (ovine epidemiology - w/o dry season)
|
-East Africa
-hypbiosis unimportant -high burden year round -high worm fecundity -often year round anthelmintic -# of L3 on pasture dependent on rainfall |
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haemonchosis (ovine epidemiology - w/ dry season)
|
-parts of Australia/Brazil
-dry season: L3 don't survive on pasture -high levels of inhibited larval development (dry) -parasite survives predominantly in host -outbreaks at start of wet season (reactivation of inhibited L3 & rapid increase in pasture L3s) |
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aelurostrongylus abstrusus life cycle (cat)
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ID
|
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ancylostoma caninum life cycle
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ID
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ancylostoma head
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ID
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ancylostoma head
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ID
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anoplocephala perfoliata (head)
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ID
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anoplocephala perfoliata egg
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ID
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anoplocephala perfoliata life cycle
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ID
|
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bunostomum phlebotomum
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ID
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bunostomum trigonocephalum
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ID
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cestode
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ID
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chabertia ovina life cycle
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ID
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cooperia
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ID
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cooperia head
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ID
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dictyocaulus viviparus (adult worms)
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ID
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dictyocaulus viviparus (L1 larvae)
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ID
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dictyocaulus viviparus (L1 larvae)
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ID
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dipylidium caninum (adult worm)
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ID
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dipylidium caninum (egg packet)
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ID
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dipylidium caninum (head)
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ID
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dipylidium caninum (segments double genital pore)
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ID
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dipylidium caninum life cycle
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ID
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dirofilaria immitis (in dog heart)
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ID
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dirofilaria immitis life cycle
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ID
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echinococcus (adult SI dog)
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ID
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echinococcus eggs
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ID
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dirofilaria immitis life cycle
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ID
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echinococcus multilocularis
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ID
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echinococcus multilocularis life cycle
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ID
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haemonchus
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ID
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haemonchus contortus (color)
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ID
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haemonchus female tail
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ID
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haemonchus head
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ID
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haemonchus male bursa
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ID
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haemonchus male tail
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ID
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haemonchus vulval flap
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ID
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Hetarakis male tail
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ID
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hydatid cyst (IMH)
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ID
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hydatid sand
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ID
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metastrongylus egg
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ID
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metastrongylus spp life cycle (pigs)
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ID
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muellerius capillaris (L1 larva)
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ID
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nematode anatomy
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ID
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nematode anatomy
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ID
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nematode anatomy
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ID
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nematode morphology (head) 1
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ID
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nematode morphology (head) 2
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ID
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nematode morphology (male tail) 1
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ID
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nematodirus battus egg
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ID
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nematodirus battus epidemiology
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ID
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nematodirus battus life cycle
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ID
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nematodirus egg
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ID
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nematodirus egg (typical)
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ID
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nematodirus male tail
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ID
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nematodirus species egg
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ID
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number of adult parasites and FECs
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ID
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oesophagostomum radiatum
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ID
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oesophagostomum venulosum
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ID
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oslerus osleri larvae (L1 in sputum)
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ID
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oslerus osleri larvae (L1 in sputum)
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ID
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oslerus osleri larvae (L1 in sputum)
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ID
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ostertagia circumcincta life cycle
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ID
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ostertagiosis epidemiology (ovine)
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ID
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ostertagiosis nodules 1
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ID
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ostertagiosis nodules 2
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ID
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ostertagiosis nodules 2
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ID
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ostertagiosis nodules 2
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ID
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ostertagiosis nodules 2
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ID
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ostertagiosis type II epidemiology
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ID
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parafilaria (adult in tissue)
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ID
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PGE in UK
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ID
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pilobolus (fungus aids dispersal)
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ID
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srongylus vulgaris head
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ID
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strongylus equinus head
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ID
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strongylus equinus head
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ID
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taenia (gravid segment)
|
ID
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taenia saginata life cycle
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ID
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taenia vs dipylidium (genital pore)
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ID
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tapeworm segment (gravid segment)
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ID
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tapeworm segment (mature segment)
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ID
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toxascaris leonina egg (dog&cat)
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ID
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toxascaris leonina head (dog&cat)
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ID
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toxascaris leonina larvae (sheathed infective)
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ID
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toxicara
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ID
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toxicara canis egg
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ID
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toxicara canis egg 1
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ID
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toxicara canis egg 2
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ID
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toxicara canis fecundity
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ID
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toxicara canis head
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ID
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toxicara canis larvae (infective)
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ID
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toxicara canis life cycle (pups to 3mo)
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ID
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toxicara cati (b&w)
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ID
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toxicara cati egg
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ID
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toxicara vitulorum adults (30cm)
|
ID
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toxicara vitulorum egg (cattle)
|
ID
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toxocara vitulorum larvae (sheathed infective)
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ID
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Trichostongylus axei
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ID
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trichostrongyle egg
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ID
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trichostrongyle egg (typical)
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ID
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trichostrongylid egg
|
ID
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trichostrongylus colubriformis
|
ID
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trichostrongylus head
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ID
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trichuris (whipworm)
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ID
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trichuris globulosa (whipworm)
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ID
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trichuris globulosa egg
|
ID
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trichuris life cycle (vulpis & suis)
|
ID
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trichuris vulpis egg
|
ID
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uncinaria head
|
ID
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uncinaria stenocephala egg
|
ID
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uncinaria stenocephala life cycle
|
ID
|
|
haemonchosis (ovine epidemiology - temperate)
|
-larvae do NOT surve over winter
-survives winter inside host -reacivate in spring -lambs ingest L3 in summer |
|
nematodes of sheep small intestine
|
Nematodirus (Trichostrongyloidea)
Trichostrongylus (Trichostrongyloidea) Cooperia (Trichostrongyloidea) Bunostomum (Strongyloidea) Strongyloides (Rhabditoidea) |
|
nematodirus battus (epidemiology)
|
-May to July peak
-very young lambs -earlier than others |
|
nematodirus battus (life cycle)
|
-PPP = 14 days
-develops to L3 inside egg -only free living L3 infective (ingested) -hatching requirements: prolonged period of chill followed by day/night temp of 10 degrees -eggs hatch in mass the following spring |
|
nematodirus battus (host age resistance)
|
-lambs susceptible from 3wks to 3mo
-ewes very resistent -physiological immunity (not acquired) |
|
nematodirus battus (epidemiology)
|
-lamb to lamb disease
-L3s hatch in spring from eggs passed onto pasture from last years lambs -hatching (L3) must coincide with presence of susceptible lambs (2wk - 3mo) -depends on climate and lambing period -mild spring / late lambing or late spring / early lambing = low risk |
|
nematodirus battus (pre-patent period)
|
14 days (short)
|
|
nematodirus battus (pathogenesis)
|
-due to larval stages
-severe disruption of SI mucosa -most damage 10-12d post infection (L4-L5 moult) -eneritis and villus atrophy |
|
nematodirus battus (clinical signs)
|
-rapid onset (10-12d PI)
-profuse diarrhea -dehydration (increased thirst) -lambs affected (ewes normal) |
|
nematodirus battus (diagnosis)
|
-FECs not reliable (CS due to larvae)
-grazing history -clinical signs |
|
Nematodirus (others)
|
-eggs develop to L3 in egg but no special hatching requirements
-part of mixed infection -contribute to PGE (late summer) |
|
trichostrongylus species in sheep small intestine
|
*Trichostrongylus vitrinus
Trichostrongylus capricola NB: T. colubriformis (ruminants) |
|
trichostrongylus (temperate - UK)
|
-primary pathogen or mixed
-acute PGE in lambs (autumn/early winter) -very dark faeces -chronic wasting disease of hoggs & ewes in early winter -poor skeletal growth & wool quality |
|
trichostrongylus (pathology)
|
-larvae and adults burrow beneath surface epithelium
-enteritis -mucus and mucosal hypertrophy -lamina propria infiltrated with inflammatory cells -villi shortened & atrophy -resistance brings localalized 'fingerprint' lesions |
|
cooperia curticei
|
-small intestine of sheep
-not very pathogenic -adults 1cm with large bursa -'watch spring' appearance -type triconstrongyloidea life cycle |
|
bunostomum trigonocephalum
|
-superfamily strongyloidea
-sheep and goat hookworm (sucks blood) -small intestine -adult 1-3cm with hooked anterior |
|
bunostomum trigonocephalum (life cycle)
|
-typical hookworm
-PPP = 1-2mo -infective L3 -percutaneous route with pulomanary migration -oral route (no pulmonary migration) |
|
nematodes of sheep large intestine
|
Chabertina ovina (Strongyloidea)
Oesphagostomum spp. (Strongyloidea) Trichuris ovis (Trichuroidea) |
|
chabertia ovina
|
-large intestine
-adult 1.5-2cm with large buccal capsule -plug feeders (mucosa not blood) -very common -low level of infection -contributes to PGE |
|
chabertia ovina (life cycle)
|
-PPP = 42 days
-hatch L1 -L3 ingested and into SI or LI mucosa -moults to L4 (1 week) and to caecum -L4 can arrest -L5 migrates to colon |
|
chabertia ovina (pathogenesis)
|
-200 to 300 worms for disease
-mucosal damage -haemorrhage -protein losing enteropathy -diarrhea (mucoid) +/- anaemia |
|
oesophagostomum species in sheep
|
-oesophagostomum columbianum (nodules)
-oesophagostomum venulosum (no nodules) -adults 1-2cm |
|
GI nemeatodes of goats
|
-generally same as sheep
-goats more susceptible (browsing animals) -acquired immunity less effective -treat all age groups (higher dose than sheep b/c metab) -faster drug resistance |
|
fecal egg count (FEC) limitations
|
-FEC and worm burden not linear relationship
-heavy burden may have low FEC -individual does not represent status of herd -does not differentiate between trichostrongyle species (xcept nematodirus) |
|
fecundity between species (daily egg production)
|
haemonchus 5k-15k
ostertagia 100-200 trichostrongylus 100-200 cooperia 1k-3k nematodirus 50-100 oesophagotomum 5k-10k chabertia 5k-10k |
|
nematodes with -ve FEC during acute outbreak
|
-ostertagiosis type II (cattle)
-nematodirus battus (sheep) |
|
FECs sufficient for clinical disease
|
Ostertagia:
200 epg (none) 200 to 1000 epg (mild) >1000 epg (heavy) Haemonchus: 1k to 20k Nematodirus: often low or -ve with significant worm burdens |
|
gut nematodes of small animals
|
-toxocara canis (dog)
-toxocara cati (cat) -toxocara vitulorum (cattle) -toxocaris leonina (dog/cat) |
|
toxicara canis
|
-egg thick and pitted (resistant)
-adult 10-18cm -3 lips |
|
toxicara cati
|
-egg thick and pitted (resistant)
-alar flap -arrowhead appearance |
|
toxocara vitulorum
|
-cattle
-egg pitted but thinner -infective larvae sheathed -large adults (30cm) |
|
toxocaris leonina
|
-dog/cat
-egg smooth -infective larvae small & sheathed -pointed head (adult) |
|
toxocara canis (routes of infection)
|
-oral (direct): infective larvae in egg
-transplacental -transmammary -paratenic host |
|
toxocara canis (outcome of infection)
|
<3mo - adult develops in SI
>3mo - larvae arrest in tissues |
|
toxocara canis (life cycle < 3mo)
|
-PPP = 4-5 wks
-adults in SI -eggs with L2 ingested -L2 hatches in SI -via liver to lungs (L2-L3) -L3 coughed and swallowed (to SI) |
|
toxicara canis (life cycle > 3mo)
|
-PPP = 16d-3wk
-adult in SI -L2 ingesteed and hatches in SI -L2 arrests in tissues -L2 reactivates ~3 week pre-partum -L2 migrates to foetal lung (to L3) -L3 in pup coughed and swallowed |
|
toxicara canis (transplacental transmission)
|
-infective larvae reactivated 3 week pre-partum
-migrates to fetal lung (moults to L3) -L3 to SI via trachea -ensures 100% infection |
|
toxicara canis (transmammary transmission)
|
-L3 in milk up to 5wk post-parturition
-no migratory phase |
|
toxicara canis (arrested larval development)
|
-arrested L2 hypobiotic: resistant to anthelmintics
-survive for life of bitch -reactivate when immunity lowered at pregnancy |
|
toxicara canis (paratenic hosts)
|
-L2 arrest in bird/rodent/invertebrate
-more important in T. cati -PPP ~3wk |
|
toxicara canis (egg)
|
-thick and pitted
-sticky and resistant -unembryonated egg (freshly shed) not infective -females very fecund |
|
toxicara canis (clinical signs)
|
1. migratory phase - coughing, increased resp, pneumonia (heavy)
2. eneral phase - pot bellied pups, failure to thrive |
|
toxicara canis (treatment)
|
-goal to prevent environmental contaminatin
-min PPP ~16d: treat before eggs -high dose Fenbendazole (3wk pre-partum, 2wk post) kills reactivated L2 |
|
toxicara canis (pre-patent periods)
|
-transplacental: 16d-3wk pups
-transmammary: ~4wk from birth -paratenic host: 3wk hunting & scavenging dogs -direct: 4-5wk all dogs |
|
toxicara cati
|
-no transplacental infection
-transmammary most important -no migratory phase -PPP ~8wk -diarrhea, pot-belly, poor coat |
|
toxicara vitulorum
|
-exotic cattle (not UK)
-PPP ~3-4wk -transmammary route most important (up to 30d) -no tissue migration in calf |
|
toxascaris leonina
|
-cats/dogs very common
-direct: egg containing L2 -no migratory phase -PPP ~11wk -smooth shell -paratenic host (eg. L2 in tissue of mice) |
|
ancylostoma caninum (head) - what feature differentiates it from uncinaria species?
|
teeth (cutting plates in uncinaria)
|
|
uncinaria stenocephala (head) - what feature permits identification?
|
cutting plates
|
|
trichuris vulpus egg - features
|
mucus plugs (bipolar)
|
|
trichuris species - where in the host?
|
large intestine
|
|
ancylostoma species - where in the host?
|
small intestine
skeletal tissue lungs |
|
superfamily strongyloidea species (hookworms)
|
uncinaria stenocephala (dog, cat, fox)
ancylostoma caninum (dog) ancylostoma braziliense (dog/cat) ancylostoma tubaeforme (cat) |
|
hookworm features (strongyloidea)
|
-1 to 3 cm, stout, hooked head
-small intestine -direct lifecycle -L3 infective (sheathed - L3 with L2 cuticle) -important in tropics |
|
uncinaria stenocephala (general)
|
-northern (fox) hookworm
-dog, cat & fox -oral infection (L3) -no percutaneous route -no transmammary infection -PPP = 14-21d |
|
uncinaria stenocephala (pathology)
|
-not voracious blood sucker
-grazes on SI mucosa -protein losing enteropathy -hypersensitivity response -pedal dermatitis (tries to get through skin of foot pad but can't and dies) |
|
ancylostoma caninum (transmammary infection)
|
-very important in pups
-bitch can infect 3 consecutive litters -reactivating L3 can produce patent infection in bitch -control difficult |
|
ancylostoma caninum (pathogenesis)
|
-simple haemorrhage (hookworm)
-immature and adult worms feed -anaemia (secretes anticoagulant) -worms change feeding site up to 6x per day (bleeds) |
|
ancylostoma caninum (epidemiology)
|
-younger animals (immunity in older)
-warmer climates -2 sources of infection (transmammary and percutaneous) |
|
ancylostoma caninum (control)
|
-benzimidazoles
-ivermectin/moxidectin -fenbendazole (high dose in pregnant bitch) -clean dry bedding (earth or grass runs support L3 survival) |
|
ancylostoma caninum (eggs)
|
-typical strongyle egg
-pathogenic in prepatent phase -can have anaemia but no eggs in faeces |
|
ancylostoma braziliense
|
-cats and dogs
-not blood sucking -protein losing enteropathy -cutaneous larva migrans (man) - creep under skin |
|
trichuris species (trichuroidea)
|
-trichuris vulpis (dogs)
-trichuris suis (pigs) |
|
trichuris (general)
|
-whipworms
-thin anterier and thicker poster (repro organs) -direct life cycle -PPP = 6-12wk -L1 infective (penetrates LI mucosal glands) |
|
trichuris vulpis (pathology)
|
-usually asymptomatic
-watery diarrhea +/- blood |
|
trichuris (egg)
|
bipolar mucoid plugs
|
|
metastrongyles (metastrongyloidea)
|
-indirect life cycle
-IMH = molluscs -clinically mild / asymptomatic (usually) |
|
oslerus osleri
|
-host: dog & wild canid
-NO IMH -site: nodules at tracheal bifurcation -thin (1-1.5cm) |
|
oslerus osleri (life cycle)
|
-direct (PPP = 10-18wk)
-adults in tracheal nodules -hatched L1 coughed up and swallowed -L1 to pup in sputum or environ -L2 in SI -L3 to L5 in alveoli and bronchi before migrating to trachea |
|
oslerus osleri (clinical signs)
|
-usually asymptomatic
-dry cough +/- (as nodules grow) -exercise intolerance -dogs 6-12mo (esp. working dogs) |
|
oslerus osleri
|
-chronic dry cough and exercise intolerance
-L1 in sputum (or faeces) -bronchoscopy (nodules & L1) -L1 has distinctive 'S' shaped tail |
|
oslerus osleri (epidemiology)
|
-nursing bitch often focus of infection
-L1 immediately infective |
|
aelurstrongylus abstrusus
|
-host: cat
-IMH: molluscs -site: lung parenchyma and small brionchioles (lungworm) |
|
aelurstrongylus abstrusus (life cycle)
|
-PPP = 4-6wk
-adult in lungs -eggs hatch almost immediately -L1 in faeces -L1 to L3 in IMH -L3 in IMH infective (IMH ingested and to lungs by lymph of blood) |
|
aelurstrongylus abstrusus (pathologenesis)
|
-not very pathogenic
-small granulomas in lung -rarely, larger lesions -muscular hypertrophy/plasia -granulomas soon resolve -widespread (ubiquitous IMH) |
|
aelurstrongylus abstrusus (clinical signs)
|
-mild
-chronic moist cough (esp. after handling) -mild dysnopea -dignosis: L1 in faeces |
|
angiostrongylus vasorum
|
-host: dog
-IMH: molluscs -site: right ventricle, pulmonary artery -small brown worms (~2.5cm) -aka 'French' heartworm |
|
angiostrongylus vasorum (life cycle)
|
-PPP = 7 weeks
-adults in heart -eggs hatch in pulmonary capillaries -L1 to alveoli and up lungs -L1 in faeces (L1-L3 in IMH) -IMH ingested (L3) and L4-L5 in mesenteric lymph nodes before right heart |
|
angiostrongylus vasorum (pathogenesis)
|
-chronic congestive cardiac failure
-fibrosis in arteries ('pipe stem' feel) -lung mottled (penetrating L1) |
|
angiostrongylus vasorum (clinical signs)
|
-early: asymptomatic
-later: increased resp / cough on exercise -fainting -s.c. haematoma -diagnosis: L1 in faeces (characteristic tail) -warm damp winters (increase in slugs) |
|
filariodea species (filarial worms)
|
-dirofilaria immitis
-inchocerca species -parafilaria species |
|
filarial worms
|
-tissue dwelling
-insect vectors -never in gut -primitive forms lay eggs (parafilaria) -more evolved forms release L1 or microfilaria (dirofilaria) |
|
microfilariae
|
-L1
-sheathed or unsheathed -blood or skin -periodicity: numbers peak in blood to cooincinde with biting habits of vectors |
|
dirofilaria immitis
|
-host: dog, cat, ferret, sea lion
-IMH: mosquito -site: cv system (rt ventricle, posterior vena cava, pulmonary artery) -USA, warm temperate zones (Europe), tropics |
|
dirofilaria immitis (life cycle)
|
-PPP = 6mo
-adults in heart -release unsheathed microfilariae in blood -mf ingested by mosquito (L1-L3 in 10-14d) -L3 transmitted when mosquito feeds -L3 L5 in s.c., L5 to heart |
|
dirofilaria immitis (pathogenesis)
|
-chronic congested rt heart failure
-endocarditis in valves, pulmonary endarteritis -pulmonary embolism -vena cava syndrome -glomerulonephritis |
|
dirofilaria immitis (clinical signs)
|
-cardiovascular dysfunction
-listless/gradular loss of condition -exercise intolerance -chronic soft cough |
|
dirofilaria immitis (diagnosis)
|
-microfiliae in blood
-circulating antigen (currently infected cf antibody) -clinical signs |
|
dirofilaria immitis (cats)
|
-very pathogenic (better adapted to dog)
-adult worms live shorter time -mf are transient -less prevalent than in dogs |
|
dirofilaria immitis (dog vs cat)
|
DOG: v. susceptible, worms live 5-7yr, 30+ worms, heart and lungs, persistent microfilaemia
CAT: less susceptible, worms live 2-3yr, <6 worms, lungs only, transient microfilaraemia |
|
dirofilaria immitis (prophylaxis)
|
-macrocyclic lactones monthly(Ivermectin, milbermycin, selamectin) - kills L3/L4 up to 6wk pi
-DEC (diethylcarbamazine) daily -prophylactic drugs do not kill adult worms (maybe steralize females) |
|
dirofilaria immitis (mf status and prophylaxis)
|
-Ivermectin and particularly DEC are microfilaricidal at prophylactic doses
-if mf +ve dog treated, can induce anaphylctic shock -dogs must be mf -ve before treatment! |
|
dirofilaria immitis (prevention)
|
-keep animals inside at peak mosquito biting times (dusk)
-insecticide collars or spot-on -reduce mosquito population (dfficult) |
|
onchocerca species
|
-onchocerca cervicalis (horse)
-onchocerca gutturosa (cattle) -onchocerca lienalis (cattle) -onchocerca volvulus (humans) |
|
onchocerca cervicalis
|
-host: horse
-IMH: culiicoides (midges) -microfilaria in skin |
|
onchocerca gutturosa and onchocerca lienalis
|
-host: cattle
-IMH: simulium (black flies) -microfilariae in skin |
|
parafilaria species
|
-host: cattle, buffalo, horse
-IMH: muscid flies -site: sc and im connective tissue -distribution: s. europe, sweden, africa, asia -stick tail through skin to lay eggs (skin lesions) |
|
habronema microstoma (spiroidea)
|
-host: horses/donkeys
-IMH: muscid flies -site: adults in stomach -related to filarial worms |
|
habronema microstoma (summer sores)
|
-horse/donkey
-cutaneous infestation by L3 -L3 deposited on skin (often around eyes) -warm weather (often on dark coated horses) -no further development |
|
aleurostrongylus abstrusus (prediliction site)
|
lung (mildly pathogenic)
|
|
dirofilaria immitis (dog) - sheathed?
|
no
|
|
lungwomrs (large animal)
|
-trichostrongyloidea (direct)
-metastrongyloidea (indirect) |
|
trichostrongyloidea species
|
lungworms:
-dictyocaulus viviparus (cattle) -dictyocaulus arnfieldi (horse & donkey) -dictyocaulus filaria (sheep & goats) -dictyocaulus eckerti (deer) |
|
dictyocaulus viviparus (life cycle)
|
-PPP = 26d
-adults in bronchi/trachea -hatched L1 up trachea and swallowed -L1 in faeces -L3 infective (ingested) -L4 in lymph nodes to lungs |
|
dictyocaulus viviparus
|
-adults up to 8cm (slender)
-L1 larvae in faeces (NOT eggs) -bigger than haemonchus but slender & thread-like -dark brown granules in worm intestine |
|
dictyocaulus viviparus (immunity)
|
-strong & rapid acquired immunity following infection
-requires boosting by natural challenge (otherwise will become susceptible again) |
|
dictyocaulus viviparus (parasitic bronchitis)
|
-penetration phase (0-7d): larvae migrate to lungs
-prepatent phase (8-25d): larvae migrate up through lungs -patent phase (26-60d): adults producing eggs -postpatent phase (61-90d): adults expelled from airways by immune system |
|
dictyocaulus viviparus (prepatent phase)
|
-L4/L5 migrating up respiratory tree
-acute inflammatory response (monocytes & eosinophils) -heavily infected calves can die from 15d on -clinical signs 1st seen |
|
dictyocaulus viviparus (patent phase)
|
-lesions in airways (adults): inflammatory response, hyperplasia of bronchial epithelium and, interstitial emphysema
-lesions (aspirated eggs/larvae): granulomatous response |
|
dictyocaulus viviparus (postpatent phase)
|
-most animals recover gradually (strong acquired immunity)
-some (up to 25%) clinical signs increase due to: 1. alveolar epithelialization - squamous changes to cuboidal around alveoli (less gas exchange) 2. bacterial infection (acute interstitial pneumonia) |
|
dictyocaulus viviparus (clinical signs)
|
MILD (100 worms): intermittent cough
MODERATE: cough at rest, tachypnoea, hyperpnoea SEVERE (1000 worms): harsh cough, tachypnoea, dyspnoea, mouth breathing, pyrexia (secondary bacterial infection), sc emphysema |
|
dictyocaulus viviparus (reinfection syndrome)
|
-immune animals exposed to massive larval challenge (no adults)
-lots of larvae killed in lungs by immune sys -no L1s in faeces (no patent infection) -coughing and slight tachypnoea (mild syndrome) -small lymphoid nodules surrounding dead larvae |
|
dictyocaulus viviparus (diagnosis)
|
-clinical signs
-time of year -grazing / vaccination / anthelmintic history (usually grazing animals) -eosinophilia -bronchial lavage -ELISA (adult & L3 antigens) |
|
dictyocaulus viviparus (epidemiology)
|
-temperate regions (high rainfall)
-acquired immunity strong (requires boosting) -all age groups (unlike ostertagia and GIT parasites) -carrier animals (survival of latent L4) -outbreak unpredictable |
|
dictyocaulus arnfieldi
|
-host: *donkeys & horses
-life cycle similar to D. viviparus (xcept eggs in faeces) -PPP = 2-4mo -reaches patentcy in donkeys and horse foals/yearling (not adult) |
|
dictyocaulus arnfieldi (clinical signs)
|
-donkeys: usually none (true definitive host)
-horse: chronic cough and tachypnoea (larval stages) |
|
dictyocaulus arnfieldi (diagnosis)
|
-donkey: eggs or L1s in faeces
-horse: usually no eggs or L1s, grazing / anthelmintic history, co-grazing with donkeys |
|
dictyocaulus filaria
|
-sheep and goats
-PPP = 5wk -sporadic disease: lambs/yearlings in autumn -clinical signs milder than D. viviparus (chronic cough, unthriftness, nasal discharge) |
|
dictyocaulus filaria (diagnosis)
|
-L1 in faeces (Baerman technique)
-cuticular knob on anterior |
|
metastrongyloidea species
|
-metastrongylus apri (pig)
-metastrongylus salmi (pig) -metastrongylus pudendotectus (pig) -muellerius capillaris (sheep & goats) -protostrongylus rufescens (sheep & goats) |
|
metastrongylus spp. (life cycle)
|
-PPP = 4wk
-adult in small bronchi and bronchioles -eggs in faeces -IMH earthworms (L1-L3) -L3 penetrates intestinal mucosa -L4 in lymph nodes to lungs |
|
metastrongylus apri and spp.
|
-adults 6cm (slender)
-most infections light and asymptomatic -heavy infections: coughing, dyspnoea, nasal discharge -pigs 6-8mo (access to earthworm) -eggs in faeces |
|
tachypnoea
|
increased respiratory rate
|
|
hyperpnoea
|
increased respiratory depth
|
|
dyspnoea
|
difficulty breathing
|
|
muellerius capillaris
|
-sheep & goats
-widespread & common -brown hair-like worms in alveoli (1-3cm) -IMH: snails and slugs -not pathogenic -'lead shot' lesions |
|
muellerius capillaris (L1 larvae)
|
L1s in faeces differentiated from D. filaria by:
-smaller size -absence of anterior cuticular knob -dorsal spine on tail |
|
horse nematodes
|
-small strongyles (cyathostomins)
-large strongyles |
|
cyathostomins
|
-small strongyles (small red worms)
-primary parasitic pathogen of horses -many species -common -not migratory -may be very pathogenic |
|
cyathostomins (life cycle)
|
-PPP = 2-3mo+
-adults in caecum and colon -L1 to L3 on pasture -L3 penetrates LI wall (may arrest) -L4 emergence |
|
cyathostomins (pathogenesis)
|
-larval stagees (in LI): goblet cell hypertrophy
-L4 emergence: eosinophil infiltration ++, catarrhal / haemorrhagic enteritis -adults feeding: protein losing enteropathy |
|
cyathostomins (clinical signs)
|
-weight loss
-anaemia -poor performance -colic |
|
larval cyathostomosis
|
-associated with arrest larvae (can be millions)
-larvae reactivated all at once -very pathogenic (diarrhea, dehydration, 50% fatality) |
|
horse strongyles (epidemiology)
|
-no strong immunity
-horses of all ages can pass eggs -pasture contaminated by: 1. re-emergence & development of cyathostomins (spring) 2. over-wintered L3 (sheathed - resistant) |
|
cyathostomins (risk factors)
|
-high stocking densities
-over grazing -use of pasture by multiple horses -presence of young animals -warm damp weather -horses with high FEC |
|
cyathostomins (wormers)
|
-pyrantel
-ivermectin + praziquantiel (not for autumn/winter or risk reactivating larvae) -moxidectin -fenbendazole (claims to kills arrested larvae) |
|
large strongyles (horse)
|
-*strongylus spp (migratory)
-triodontophorus spp (non-migratory) |
|
large strongyles (life cycle)
|
-adults in LI
-L1 to L3 on pasture -L3 ingested (sheathed) -L4 to prediliction site -L5 remigration |
|
large strongyles (larval prediliction sites & PPP)
|
-strongylus vulgaris (most pathogenic): cranial mesenteric artery (6-7mo)
-strongylus edentatus: liver, hepatic lig, flank (10-12mo) -strongylus equinus: liver, pancreas (8-9mo) |
|
strongylus vulgaris (pathogenesis of larval stages)
|
-arteritis
-thrombosis +/- aneurism -infarction & necrosis of associated intestine -very pathogenic (L5 migrates to intestine - forms nodules) |
|
strongylus edentatus(pathogenesis of larval stages)
|
-pathological changes in liver and subperitoneal tissues
-not as pathogenic as s. vulgaris |
|
large strongyles (adult pathogenesis)
|
-plug feeders (large buccal capsules)
-ulceration -haemorrhage -protein losing enteropathy |
|
large strongyles (clinical signs)
|
-unthriftness
-anaemia -colic (S. vulgaris) |
|
triodontophorus species
|
-triodontophorus serratus
-triodontophorus tenuicollis -triodontophorus brevicauda -triodontophorus minor |
|
triodontophorus (features)
|
-adults in large intestine
-contribute to mixed strongyle infection (not on own) -shallow buccal capsule -3 sets of teeth |
|
horse nematodes
|
-small strongyles (cyathostomins)
-large strongylus (strongylus spp) -parascaris equorum -oxyuris equi -strongyloides westeri |
|
parascaris equorum
|
-foals and yearlings
-large white worm (~40cm) -SI (duodenum & proximal jejunem) -age resistance (>6mo) -unthriftness |
|
parascaris equorum (life cycle)
|
-PPP = 10-15wk
-adults in small intestine -L2 (inside egg - 2wk) infective -hatches after ingestion (L2 to liver via portal sys) -L3 to lungs (coughed and swallowed - L4 in SI) |
|
parascaris equorum (pathogenesis)
|
-migrating larvae damage:
1. liver: focal haemorrhage and fibrosis 2. lungs: focal haemorrhage, lymphocyte infiltration, nodules -adult worms in intestine: little pathology (unless very large burden - impaction, peritonitis) |
|
parascaris equorum (clinical signs)
|
1. ill thrift:
-adults in SI -foals and yearlings -immunity in older horses 2. respiratory signs -due migrating larvae -foals: coughing +/- greyish nasal discharge |
|
parascaris equorum (epidemiology)
|
-foal/yearling to foal/yearling
-females very fecund (FEC high) -eggs very resistant and sticky (can survive several years on pasture) -eggs build up on pasture towards end of season |
|
parascaris equorum (treatment/control)
|
-adults susceptible to all major classes of anthelmintics
-migratory stages only partly susceptible -small strongyle control will also control -may control in animal but pasture still contaminated |
|
strongyloides westeri
|
-worldwide
-adults small (<1cm) -only females are parasitic -common in foals <6mo |
|
strongyloides spp (life cycle)
|
-complex: free living stage and parasitic stage
-adult females in SI -eggs to L3 free living -L3 (unsheathed) to parasitic stage: skin penetration or ingestion -to lungs (L3-L5) -also transmammary route (L3 initially dormant in muscle - no migration) |
|
strongyloides westeri (clinical signs)
|
-only in very young animals (few weeks)
-requires heavy burden -signs non-specific: diarrhea, anorexia, dullness, reduces weight gain |
|
strongyloides westeri (diagnosis)
|
-clinical signs
-larvated eggs in faeces (smaller than strongyle egg) -high FEC may be seen in healthy animals |
|
strongyloides westeri (epidemiology)
|
-free living L3 not very resistant (unsheathed)
-warm and wet conditions, poor hygiene helps L3 survival -transmammary route important -not really a strongyloid |
|
oxyuroidea species
|
oxyuris equi (horse)
enterobius vermicularis (human) -pinworms -large intestine |
|
oxyuris equi
|
-pinworm
-large intestine common -adult female to 10cm (male 1cm) -long pointed tail |
|
oxyuris equi (life cycle)
|
-PPP = 5mo
-adults in colon -eggs laid at anus -L1 to L3 inside egg (L3 egg shed) -hatched L3 ingested and penetrates colonic mucosa |
|
oxyuris equi (clinical signs)
|
-adults in LI usually asymptomatic
-egg laying activity can cause intense prineal irritation (rubbing) -alopecia/inflammation over rump and tail head |
|
oxyuris equi (epidemiology)
|
-infective stage (L3) may be reached on perianal skin
-usually flakes of skin with eggs rubbed off -little immunity -heavy burdens may build in infected stables -susceptible to many anthelmintics (small strongyle control will work for this too) |
|
oxyuris equi (diagnosis)
|
-eggs around the perianal region (usually not in faeces)
-scraping + micro exam of eggs -adults in faeces -clinical signs |
|
nematodes of birds
|
-syngamus trachea (strongyloidea)
-ascaridia galli (ascaridoidea) -heterakis gallinarum (ascaridoidea) -capillaria sp. (trichuroidea): related to trichuris |
|
syngamus trachea (strongyloidea)
|
-domestic fowl & game birds
-adults in trachea -adults permanantly in copula -adults Y shaped (male & female) -aka 'gapeworm' |
|
syngamus trachea (routes of transmission)
|
1. ingestion of L3 (IN the egg)
2. ingestion of hatch L3 3. ingestion of paratenic host (earthworm) containing L3 *L3 penetrates SI and migrates in blood to lungs |
|
syngamus trachea (pathogenesis)
|
-migration of many larvae: acute pneumonia and death
-adults: haemorrhagic tracheitis -partial airway occlusion: "gapes" (gasps) |
|
syngamus trachea (clinical signs)
|
-depressed
-dyspneoic (pre-patent) -gasps, shakes head, cough (patent) |
|
syngamus trachea (diagnosis)
|
-barrel shaped egg with bipolar operculum
-clinical signs |
|
syngamus trachea (epidemiology)
|
-young birds (adults are carriers)
-turkeys of all ages -esp. outdoors -eggs very resistant -infections can come from wild birds |
|
ascaridia galli (ascaroidea)
|
-chickens & turkeys
-small intestine -large white worm (~12cm) -oval egg (smooth shell) -L2 (in egg) infective -not migratory -not very pathogenic |
|
ascaridia galli (diagnosis)
|
-eggs difficult to distinguish from heterakis gallinarium
-eggs thick shelled and resistant -does not look like toxicara egg |
|
heterakis gallinarum
|
-domestic and wild birds
-ascarid but in LI -small white worm (~1.5cm) -not migratory -not pathogenic -eggs similar to ascaridia |
|
heterakis gallinarum (pathology)
|
-not pathogenic in itself
-importance as vector of histomonas meleagridis -histomonas transmitted from bird to bird in heterakis egg -causes 'blackhead' in turkeys |
|
capillaria (birds)
|
-prediliction site depends on species (crop and oesophagous or SI)
-similar to trichurs spp (hookworm) -eggs parallel sides with bipolar plugs |
|
phylum platyhelminthes
|
flatworms:
-cestodes: tapeworms -trematodes: flukes |
|
cestodes (structure)
|
-segmented body (tapeworm)
-hermaphrodite -no alimentary canal -scolex (head): suckers, rostellum and hooks (armed) -strobila (chain of segments or proglottids) |
|
scolex
|
head of an adult cestode (tapeworm) - suckers, rostellum and hooks (armed)
|
|
strobila
|
in adult cestode (tapeworm): chain of segments or proglottids
|
|
cestode (tapeworm) segments
|
-mature: organs of repro
-gravid: eggs only (in uterus) |
|
taenia egg (cestode)
|
-radially striated shell or embryophore
-hexacanth (6-hooked) embryo or oncosphere |
|
cestode (larval stages)
|
-cyst contains head(s) of future tapeworm
-ingested by final host (cyst digested & head latches onto SI wall) -starts to bud segments |
|
taeniidae
|
host: man, cat, dog (SI)
IMH: mammal (larval stages encysted) -scolex armed (xcept T. saginata) -adults relatively non-pathogenic |
|
taenia (gravid segment)
|
organs of sexual repro in mature segment disappear as proglottid matures (uterus filled with eggs)
|
|
taeniidae species
|
-taenia saginata (man SI)
-taenia solium (man SI) -taenia multiceps (dog SI) -taenia hydatigena (dog SI) -taenia ovis (dog SI) -taenia taeniaeformis (cat) -dipylidium caninum (dog, cat, man SI) |
|
taenia saginata
|
-cestode (tapeworm)
-host: man SI -IMH: cow -adult 5-15m! -unarmed -cysticercus bovis |
|
taenia saginata (life cycle)
|
-PPP = 2-3mo
-adults in man SI -millions of eggs per day (gravid segments) -bovine ingests (oncospherese released in abomasum and penetrate SI wall) -to skeletal muscle (encysts - cysticercus bovis) -meat ingested by man (undercooked) |
|
taenia solium
|
-cestode (tapeworm)
-host: man -IMH: pig or man (v. pathogenic) -if man is IMH: auto-infection by reverse peristalsis -cysticercus cellulosae |
|
taenia solium (pathology)
|
-adult tapewrom: no pathology
-cysticerci: v. pathogenic if encysts in man (IMH) -cysts in CNS or eye |
|
taenia solium (epidemiology)
|
-close association of man & pig
-unrestricted access of pigs to human waste -poor meat inspection -latin america |
|
taenia hydatigena
|
-cestode (tapeworm)
-host: dog (SI) -IMH: sheep (cysticercus tenuicolis) -adult: ~500cm -common in abattoir (UK): condemnation of lamb livers (burrows before encysts) |
|
taenia ovis
|
-cestode (tapeworm)
-host: dog (SI) -IMH: sheep (cysticercus ovis) -adult: ~200cm -relatively common |
|
taenia multiceps
|
-cestode (tapeworm)
-host: dog (SI) -IMH: sheep (coenorus cerebralis) -causes 'gid' (unbalanced): cysts in CNS -multiple heads: single cyst results in multiple worms |
|
taenia taeniaeformis
|
-cestode (tapeworm)
-host: cat (SI) -IMH: mouse/rat (cysticercus fasciolaris) -adult: ~60cm |
|
dipylidium caninum
|
-cestode (tapeworm)
-host: SI of dog, cat, man -IMH: fleas (larvae only) & lice (all stages) -adult: ~50cm -PPP = 3wk |
|
dipylidium caninum (life cycle)
|
-adults in SI of dog, cat, man
-gravid segments shed (3wk pi) -ingested by flea/louse -cysticercoid in haemocoel (body cavity) of flea/louse -flea/louse ingested |
|
dipylidium caninum (head)
|
-rostellum with hooks
-suckers |
|
dipylidium caninum (diagnosis)
|
-egg packets
-double genital pore -active, motile segments -elongated shape (rice grain) -tx: treat parasite like others but also must treat for flea/louse |
|
taenia vs dipylidium
|
-taenia: single genital pore
-dipylidium: double genital pore |
|
echinococcus species
|
-echinococcus granulosus granulosus
-echinococcus granulosus equinus -echinococcus multilocularis |
|
echinococcus granulosus granulosus
|
-cestode (tapeworm): scolex + 3-4 segments
-host: dog & wild canids (SI) -IMH: ruminant, pig, man -zoonotic |
|
echinococcus granulosus equinus
|
-cestode (tapeworm): scolex + 3-4 segments
-host: dog/red fox (SI) -IMH: horse/donkey -NOT zoonotic |
|
echinococcus
|
-cestode (tapeworm)
-dog (SI) -scolex + 3-4 segments -eggs similar to taenia (6-hooks radially striated) -eggs passed in faeces |
|
echinococcus granulosus granulosus (life cycle)
|
-PPP = 40-50d
-adults in dog SI -gravid segments shed 1 per week (per worm) -resistant onchosphere ingested (penetrates SI) -hydatid cyst in liver/lungs (6+mo pi) -cyst ingested by host |
|
protoscoleces
|
-in cyst of echinococcus granulosus granulosus
-contain hydatid sand -immature scolexes (head without segments) |
|
echinococcus granulosus granulosus (IMH)
|
-depends on local animal husbandry (adaptable)
-sheep is natural IMH -can be camels or deer (or pig/man) |
|
echinococcus granulosus granulosus (zoonosis)
|
-man is accidental IMH
-sheep farming areas -close man/dog contact -man infected by ingestion of oncoshpheres from water, foodstuffs or coat of dog |
|
echinococcus multilocularis
|
-cestode (tapeworm)
-host: dog, cat, wild canid (fox) -IMH: rodent, man -life cycle like echinococcus granulosus granulosus -important zoonos -prevalent in Europe |
|
cestodes of the horse
|
-site: SI & LI
-IMH: mites -anoplocephala perfoliata* -anoplocephala magna -paranolocephala mamillana |
|
anoplocephala perfoliata
|
-cestode (tapeworm)
-host: horse -IMH: mite -SI & LI (ileo-ceocal colic) -ulcerations at attachment site -v. prevalent (temperate) |
|
anoplocephal perfoliata (morphology)
|
-head: suckers & lappets
-egg: pyriform apparatus (supports embryo) -adult: short & fat (segments wider than long) |
|
anoplocephal perfoliata (life cycle)
|
-PPP = 6-10wk
-adults @ ileo-caecal jxn (horse) -eggs (in faeces) ingested by mite (forms cysticercoid) -horse ingests mite (attaches to gut wall) |
|
largest nematode in horse
|
-parascaris equorum
-SI |
|
strongylus vulgaris
|
-horse LI
-large strongyle -well developed buccal capsule -2 rounded teeth at base of buccal capsule |
|
strongylus edentatus
|
-horse LI
-large strongyle -absence of teeth distinguishes from others |
|
strongylus equinus
|
-horse LI
-large strongyle -teeth larger & more pointed than S. vulgaris |
|
tridontophorus
|
-horse LI
-large strongyle -shallow buccal capsule -3 sets of teeth at base of buccal capsule |
|
cyathostomin
|
-horse
-small strongyles -shallow buccal capsule -not migratory -+/- teeth (hard to distinguish) -do not need to distinguish species |
|
oxyuris equi (egg)
|
-slightly flattene on 1 side
-mucoid plug on 1 end |
|
syngamus trachea (morphology)
|
-adults in permanent copulation (form Y shape)
-egg has operculum on both ends |
|
heterakis (morphology)
|
-male: large precloacal sucker
-prominent caudal alae & papillae |
|
pig nematodes
|
1. stomach
-hyostrongylus rubidus -trichostrongylus axei 2. small intestine -ascaris suum*** -trichinella spralis** -strongyloides ransomi 3. large intestine -oesophagostomum -trichuris suis 4. lungs -metastrongylus spp. |
|
nematodes of pigs (species)
|
-hyostrongylus: outdoor only
-ascaris: outdoor & indoor (extensive & intensive) -oesophagosomum: outdoor, indoor (extensive & intensive) -trichuris: outdoor & indoor (extensive only) |
|
hyostrongylus rubidus
|
-ostertagia of pigs (predominantly lactating sows)
-stomach -chronic gastritis -outdoor pigs only -life cycle (typical trichostrongyloid): direct, PPP = 3wk, L4 can undergo hypobiosis -clinical signs: inappetence, anaemia, loss of condition, reduce fertility -pathology: similar to ostertagia (nodule formation) -diagnosis: eggs in faeces |
|
acaris suum
|
-pig small intestine
-typical ascarid (large ~40cm) -direct life cycle -L2 in egg is infective -migratory -1 to 5 adults per host |
|
ascaris suum (life cycle)
|
-PPP = 6-8wk
-adults in pig SI -L2 inside egg is infective (hatches after ingestion) -L2 to liver via portal sys (L3 in liver) -to lungs (coughed & swallowed) -L4 in SI -typical ascarid (like toxicara canis) |
|
relationship between ascaris suum & ascaris lumbricoides
|
-closely related but separate species (look identical)
-in areas where human infection with A. lumbricoides is endemic, pigs not an important resevoir -in areas where A. lumbricoides is NOT endemic (USA), sporadic cases of human infection with A. suum (organic veg with pig faeces) |
|
ascaris suum (clinical signs)
|
-overt clinical signs rarely seen
-reduced productivity (up to 10%): food conversion efficiency, reduced weight gain, increased fattening time -occasionally transient pneumonia in young pigs (migrating larvae) -milk spot fever: cloudy white spots (up to 1cm), fibrous repair of inflammatory reaction to migrating L2/L3, liver condemnation (economically important) -diagnosis: clinical signs & history, FEC, incidence of liver contamination |
|
ascaris suum (epidemiology)
|
-can complete life cycle indoors
-very fecund (>200k worms per day per worm): eggs resistant -difficult (impossible?) to eradicate from indoor systems -primarily young pigs (strong acquired immunity in older pigs) -minimum 4 weeks maturation for egg maturation -milk spot fever in end of summer |
|
trichinella spiralis (life cycle)
|
-L1 in muscle (ingested)
-L1 infects SI mucosal epithelium & grows to adult (L1-L4) -adult lays eggs & L1 larvae penetrate SI mucosa -L1 to muscle (via lymph & blood) & encysts |
|
trichinella spiralis (pathogenesis)
|
-invades single muscle cells & encysts
-destroys actin/myosin -becomes "nurse cell" (encapsulated) -domestic cycle (pigs: infected swill, tail biting, rats) & sylvatic cycle (wild animals) |
|
trichinella spiralis (diagnosis)
|
-pigs: examination of muscle for larvae (artificial digestions with pepsin/HCl; trichinoscopy of thin muscle section)
-prediliction sites: diaghragm, intercostal muscles, tongue, masseters -serology: ELISA |
|
trichinella spiralis (clinical signs: man)
|
-transient enteritis (L1-adult)
-1 to 2 weeks later, L1 in muscle: acute myositis, pyrexia, myocarditis, periorbital oedema, ascities, eosinophilia -can be fatal -diagnosis: muscle biopsy, ELISA |
|
trichuris suis (life cycle)
|
-PPP = 6-12wk
-L1 inside egg is infective (1-2mo maturation in faeces - minimum) -on ingestion, L1 hatches & penetrates glands in caecal mucosa (4 moults occur) -adults emerge: anterior ends (narrower end of whipworm) embedded in mucosa of LI & caecum |
|
trichuris suis
|
-whipworm
-mild/moderate infections asymptomatic -can occur indoors but limited to "traditional systems" (solid floors/straw) -more common in outdoor systems (organic) -typically poor hygiene -common in uK but in low numbers |
|
trichuris suis (clinical signs)
|
-growers/finishers
-reduced growth rate -loose faeces to overt scouring -mucus in faeces -occasionally blood in faeces (severe) -facilitates invasion of pathogenic spirochetes |
|
trichuris suis (diagnosis)
|
-FEC: heavy infections up to 10k eggs
-egg: barrel shaped with mucus plug on both ends -PPP = 6-10wk: eggs only in faeces of pigs 10wk or older -FEC -ve does not rule out diagnosis |
|
oesophagostomum
|
-"nodular worm"
-oesophagostomum dentatum -oesophagostomum quadrispinulatum -cephalic vescicles on anterior (head) end -more important in pigs than cattle/sheep -usually subclinical -adults 1-2cm -more common in outdoor systems (but can be indoors: sows & boars) -infection accumulates over life of animal |
|
oesophagostomum (life cycle)
|
-PPP = 18-21d
-adults in LI -eggs in faeces: L3 ingested & enters SI or LI mucosa -may induce nodules -L4 emerges (can arrest in nodules) -L5 in LI lumen |
|
oesophagostomum (epidemiology)
|
-life cycle can be completed indoors
-L3 can survive or develop in faeces, contaminated concrete, & skin -infection accumulates with ages (higher in sows than fatteners) -with increased immunity: arrest in nodules -periparturient rise in FEC in sows (2nd half of pregnancy to weaning: treat sows 1wk before farrowing) -piglets can be born into highly infected environment -outdoor: L3s overwinter poorly in temperate regions |
|
oesophagostomum (pathology)
|
-diffuse enteritis in colon & caecum
-oesophagostomum quadrispinulatum: distinct nodules -oesophagostomum dentatum: indistinct nodules -acute infections: haemorrhage and secondary infection (form small abscesses) -chronic infections: fibrous nodules |
|
oesophagostomum (clinical signs)
|
-burdens < 5k worms: probably asymptomatic
-growing pigs: reduced weight gain -sows: poor milk yields (contributes to "thin sow syndrome"), reduced fertility -older breeding stock carry heaviest infections -diarrhea in very heavy infections (10k+ worms) -egg: similar to hyostrongylus |
|
fasciola hepatica
|
-final host: most mammals
-significance: sheep & cattle -disease: fasciolosis -distribution: temperate -IMH: lymnaea truncatula (amphibious small brown snail) |
|
fasciola hepatica (life cycle)
|
-adults (hermaphrodite) in larger bile ducts of liver (v. fecund)
-eggs (quninone tanned/yellowish): in faeces develop into egg containing MIRACIDIUM -miracidium hatches under stimulus of light (3hr to find the snail by random) -develops into 2nd laraval stage in snail: SPOROCYST -asexual repro forms multiple REDIAE w/in sporocyst (ruptures to release rediae) -2nd gen rediae formed within 1st gen: 3rd larval stage (CERCARIAE) formed w/in 2nd gen rediae -cercariae emerge from snail (rainwater stimulus) & migrate to herbage -encyst to form METACERCARIA (ingested) -excystation in SI (induces by CO2 & bile): juvenile fluke emerges (to liver for 6-8wk before bile ducts) -PPP = 10-12wk |
|
fascioloa hepatica (life cycle simplified)
|
1. EGG
2. MIRACIDIUM (light stimulus to hatch) 3. to snail 4. SPOROCYST (asexual repro) 5. REDIAE (multiple release) 6. REDIAE (2nd gen w/in 1st) 7. CERCARIAE(emerge from snail w/ rainwater stimulus) 8. attach to herbage & encyst: form METACERCARIA (ingested) 9. to LIVER (6-8wk) before BILE DUCT (adult in 4wk) 10: PPP = 10-12wk |
|
fasciolosis (acute)
|
-detected: autumn/early winter
-occurs: 2-6wk post ingestion of > 2k metacercariae -caused by: migration of juvenile flukes -results: liver damage & haemorrhage -clinical signs: sudden death, weakness, pale mucus membranes, dyspnoea, palpable liver, ascites, abdominal pain -liver PM: enlarged, rupture of subscapular haemorrhages, necrotic migration tracts, fibrinous exude (ventral lobe) |
|
fasciolosis (subacute)
|
-detected: late autumn/winter
occurs: 6-10wk post ingestion of 500-1500 metacercaria cause: juvenile migration & adult fluke in bile ducts -adults: feed on blood & damage biliary mucosa (inflammation) -results: liver damage/haemorrhage, cholangitis & anaemia -signs: rapid/severe haemorrhagic anaemia w/ hypoalbuminaemia, pale mucus membranes, enlarged liver, +/- SM oedema/ascites -liver PM: rupture of subcapsular haemorrhages is rare; similar to acute -death w/in 1-2wk if not treated |
|
fasciolosis (chronic)
|
-detected: late winter/early spring
-occurs: 4/5mo post ingestion of 200-500 metacercariae -cause: adults feeding in bile ducts -results: anaemia, hypoalbumenaemia, cholangitis -signs: loss of condition, emaciation, pale mucus membranes, submandibular oedema (hypoalbumenaemia), ascites -liver PM: irregular, pale, firm, smaller ventral lobe with fibrosis, scarring of tracts, thickened distended bile ducts -subclinical: productivity losses (fewer multiple births, reduced weight growth in lambs) |
|
fasciolosis (bovine)
|
-chronic: productivity loss (milk yield), calcification of bile ducts (extensive), gall bladder enlargement, liver fibrosis
-immune response: limits primary infection (<1yr), inhibits secondary infection -no acute form |
|
fasciolosis (epidemiology)
|
1. availability of snail habitat: muddy areas/slow moving shallow water, edges of ponds, banks of streams & ditches
2. moisture: rainfal makes motility easier 3. temperature: >10deg 4. season: snails breed May to October (increased metacercaria on pasture August to October - summer infection of snails) NB: snails infected in autumn(cold) arrest development & resume in spring (metacercaria produced May to June - winter infection of snails) |
|
fasciolosis (treatment)
|
-acute: triclabendazole (juveniles & adults) & move to clean pasture
-subacute: closantel, nitroxynil (not v. effective for juveniles) -chronic: several |
|
fasciolosis (control)
|
-drainage
-fence off saturated pasture -move sheep to drier pasture -anthelmintics: reduce fluke burden (October for acute & January for chronic), reduce pasture contamination (April/May) -bought in: treat & put on clean pasture |
|
fasciola gigantica
|
-larger
-tropical areas, SE Europe & SE USA -IMH: lymnaea auricularia (aquatic snail - not amphibious) |
|
fasciola gigantica (epidemiology)
|
-MIRACIDA: hatch at beginning of wet season, infect snails & develop by end of wet season
-CERCARIA: shed from snail at beginning & during dry season -METACERCARIA: encyst on aquatic plants or water -disease: end of dry/beginning of next wet season |
|
dicrocoelium dendriticum
|
-Europe, UK, USA
-host: sheep, cattle, horses, rabbits -site: bile ducts & gall bladder -IMH: land snails/ants -fluke |
|
dicrocoelium dendriticum (life cycle)
|
-adults in bile ducts & gall bladder eggs to faeces (dark brown w/ MIRACIDIUM already developed when passed)
-snail ingests eggs w/ miracidium: released & forms SPOROCYST -asexual repro through 2 rounds of sporocyst (no rediae stage): form CERCARIAE from 2nd gen -cercariae released & form slime balls in respiratory chamber of snail -slime balls extruded via respiratory pore & eaten by brown ant (2nd IMH) -cercariae encyst to form METACERCARIAE in body of ant (in brain: induces ant to climb to top of grass and clamp on - enslaver parasite) -final host eats ant: excystation in SI & juveniles directly up main bile duct (do not penetrate SI: less damage) |
|
dicrocoelium dendriticum (pathogenesis)
|
-heavy infection in older sheep
-fibrosis & distention of bile ducts, progressive cirrhosis, weakness, anaemia, emaciation -productivity losses: wool production, premature aging, repro |
|
paramphistomum
|
-conical maggot shaped fluke of ruminants
-adults in rumen & reticulum (forestomach) -tropics, southern USA -P. cervi & P. microbothrium -IMH: aquatic snails (lifecycle similar to F. gigantica) |
|
paramphistomum (pathogenesis)
|
-due to: juvenile intestinal phase (excyst in duodenum & attach to wall to feed for 6wk)
-result: necrosis & haemorrhage: erosion of duodenal mucosa -signs: acute gastroenteritis, marked oedema, haemorrhage, ulceration, profuse diahrrea, anaemia, hypoalbumaemia, intense thirst, anorexia -adult not associated with disease (so FEC not relavent) |
|
schistosoma
|
-cattle & sheep (tropics & S. Europe)
-IMH: aquatic snails -S. bovis (cattle/sheep), S. japonicum (man), S. matthei (ruminants) -male & female paired (female in groove of male) |
|
schistosoma bovis (life cycle)
|
-pairs of adults in mesenteric veins: deposit eggs in walls of veins
-MIRICIDIUM develops in egg (6-7d) & produces enzymes that weaken vein: rupture -crossed to gut & passed in faeces: eggs hatch almost immediately (release MIRACIDIUM to snail) -2 rounds of asexual repro via SPOROCYSTS (no redial stage) -CERCARIAE from 2nd gen sporocyst (forked tail): emerge from snail & sit on water (phototrophic & thermotrophic) -cercariae infect final host (not metacercaria!) percutaneously or by ingestion: tails lost & young flukes (schistosomulae) travel to blood via small BVs & lymphatics -circulate via heart & lungs to portal veins: copulate, become sexually mature adults & migrate to mesenteric veins -PPP = 6-7wk |
|
schistosoma (pathogeneis)
|
-inflammatory response to eggs in veins, mucosa & liver
-granuloma formation (intestinal mucosa & liver) -acute: mucosal haemorrhage, anaemia, hypoalbumaemia, hepatosplenomegaly signs: anaemia, diahrrea (mucous & blood tinged), thirst, anorexia, emaciation -chronic (cattle): marked granuloma of intestine & cirrhosis/periportal fibrosis of liver, reduced productivity |