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204 Cards in this Set
- Front
- Back
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Parasitism
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symbiotic relationship between two organism of different species in which one lives on or within the other & may cause harm
-parasite is dependant on host for survival |
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Protozoans
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-unicellular
-free living -most are microscopic -in the Kingdom Protista & are subdivided on how they move |
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4 kinds of protozoans
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-flagellates
-amoebae -ciliates -apicomplexans |
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Pathogenicity
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disease causing potential
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Flagellates
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-move with flagellums (long, whip like appendages)
-pear or bullet shaped -swim in host's body fluids -flagellates important in vet med: Giardia, Histomonas, Leishmania, Trichomonas Trypanosoma |
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Amoebae
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-move with a pseudopodia: false feet
-2 different forms: *Trophozoites: motile form; glide/flow along solid surface *Cyst: allows them to survive in adverse conditions in external environment -amorphous shape (a blob) -amoebae important in vet med: Entamoebae coli |
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Ciliates
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-covered with tiny hairs called cilia
-move by beating cilia together -2 different forms: *Trophozoites: motile form; dart & swirl in liquid media *Cyst: resistant form to survive in adverse conditions in external environment -2 kinds nuclei make them unique: macronucleus & micronucleus -ciliate important in vet med: Balantidium |
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Apicomplexans
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-shaped like a banana, comma or boomerang
-live in hosts': intestinal epithelium, white blood cells &/or reticuloendothelial system -life cycle is very integrated in the physiology of the host's body -move via undulations |
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Morphological features of Nematodes
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-multicelled
-unsegmented, long, round on both ends, circular diameter, bilaterally symmetrical -2mm to 100cm long: species dependant |
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Nematodes common name?
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roundworms
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External morphology of nematode
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-outside of body is covered by a cuticle extending into all orifices: mouth, esophagus, rectum & genitals
-cuticle is formed by the hypodermis: the thin layer directly below the cuticle -move via the somatic muscular layer: layer of muscles below the hypodermis -special muscles lining the body cavity aid in feeding & reproduction -body cavity is not a true coelom: its a pseudocoelum -pseudocoelum lined by pseudocoelomic membrane |
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Somatic muscles fiber shape?
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spindle shaped fibers
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nematode digestive tract
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-long straight tube from mouth to anus
-2 to 8 lips surround the mouth *some nematodes have papillae instead of lips -mouth to buccal cavity to esophagus to long winding intestine to outside opening *females: rectum *males: cloaca |
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nematode r
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-dioecious: have separate sexes
-males: *1 or 2 tubular testes *vas deferens leads from testes to cloaca *spicule pouch which opens female vulva during mating to allow sperm to enter -females *1 or 2 tubular ovaries *oviducts lead from ovaries to uterus *may have seminal receptacle *uterus leads to vagina which opens to outside via the vulva |
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oviparious
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eggs in the single cell stage
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oovoviviparous
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first stage larvae in egg
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larviparous
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retains eggs in uterus to incubate them & gives birth to live larvae
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cervical alae
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lateral flattened expansion of cuticle near the anterior end
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copulatory bursa
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posterior lateral expansion & holds onto or grasps females during mating
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bursa rays
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composes the copulatory bursa & are finger like projections with a thin membrane between them
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spicules
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male's penis & is associated with copulatory bursa
-very chitnous & pigmented |
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types of nematode eggs
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-ascarid
-trichostrongyle -spiiruroid -trichinelloid |
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another name for cestodes?
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tapeworms
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true tapeworms
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-long, segmented, flat, ribbon-like
-scolex: head; at extreme anterior end -scolex contains acetabula: 4 suckers allowing them to attach to intestinal lining -tegument: the body wall & absorbs nutrients from the host's intestine -rostellum: backwards facing hooks that help the tapeworm anchor; not on all tapeworms -neck: posterior of scolex; is the growth region -strobia: rest of the body extending from the neck |
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predilection site
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where tapeworms attach to intestinal lining & is not associated with feeding
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What are armed tapeworms? Unarmed tapeworms?
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armed have a rostellum
unarmed do not have a rostellum |
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Describe the order of proglottids on the body
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-immature proglottids are closes to the neck
-mature proglottids are in the middle of the body -gravid proglottids are closer to the posterior end & are the oldestr -each proglottid is a hermaphrodite: contains both male & female sex organs -each mature proglottid can cross fertilize & self-fertilize: others are too young or old -eggs in the gravid proglottids contain larval stage |
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types of tapeworm eggs
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-Dipylidium type: contain multiple hexacanths within 1 egg
-Taenia type: wide outer shell with thicker outer covering & 6 hook hexacanth within the egg -Pseudophyllidian type: oval shape with opercuolum at one end; each hexacanth has 6 hooks |
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Pyriform apparatus
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pear shaped inner most lining of certain tapeworms
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Hexacanth
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The motile six-hooked first-stage larva of cyclophyllidean cestodes; it emerges from the egg and actively claws its way through the intermediate host's intestine before development into the next larval stage
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Key features of Arthropods
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*arthropod means jointed foot
-covered by chitinous exoskeleton composed of segments -hemocoel is the body cavity & is filled with hemolymph -circulation is simple with a heart like dorsal tube that pumps hemolymph to the head -digestive systems starts with ventral mouth & ends with terminal anus -reproduce via eggs -species is dioecious: has male & females separately |
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Hemolymph
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blood like fluid bathing internal organs of arthropods
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Giardia
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flagellate that lives in the intestinal mucosa of dogs, cats, horses ruminant & exotics
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2 forms of Giardia parasites
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-trophozoite: the rarely seen motile feeding stage; is pear shaped, dorsoventrally flat, 4 pairs of flagella; has 2 nuclei with adhesive disk; anterior end looks like a pair of eyes
-mature cysts: more commonly seen; oval with refractile wall & 4 nuclei |
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Where is Giardia found?
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in feces; can cause diarrhea
-diarrhea can begin as soon as 5 days post-exposure with cysts found in feces at 1 week |
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Is Giardia zoonotic?
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yes
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Leishmania species
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-parasite of circulatory system & is rare in north America unless the dog has traveled overseas
-lives in the reticuloendothelial cells of capillaries, spleen, other internal organs & WBC (monocytes, polymorphonuclear leukocytes, macrophages) |
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Trypanosoma
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-flagellates of the peripheral blood extracellularly
-transmitted by ingesting intermediate host reduviid bug or its feces left on the mucous membranes of the final host -in humans, occasionally dogs |
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Stages of Trypanosoma
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-Trypomastigote: swimming stage; banana shaped; has undulating membrane with thin, whip tail
-Amastigote: resting cyst stage; found in heart & tissues; doesn't have flagellum |
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Trichomonas
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-pear shaped with 3-5
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Tritrichomonas foetus
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-pathogen transmitted venerally in cattle's reproductive tract
-bulls usually asymptomatic but are permenantly infected; treatment is slaughtering the animal -pregnant heifers may have early fetal death; can treat symptoms & allow to rest sexually for 3 months |
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Trichomonas gallinae
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-4 anterior flagella with an undulating membrane on one side
-causes yellow, necrotic lesions in mouth, esophagus & crop of avians - infection is usually fatal |
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Common name for Histomonas
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Blackhead
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How does Histomonas affect the host?
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-after ingesting the egg, it hataches releasing the organism. It migrates to liver & cecum, causing severe necrosis
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Entamoeba histolytica
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primarily a human pathogen but can infect animals that are in contact with infected animals
-causes amoebic dysentery: severe diarrhea -transmitted by ingesting in |
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2 forms of Entamoeba histolytica
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-trophozoite: motile feeding stage; single spherical and nucleus with an endosome in the middle
-mature cysts: are |
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Balantidium coli
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ciliate that lives in cecum & colon of dogs; large intestines of swine
-transmitted by ingesting infected cysts |
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Isospora species
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-protozoa that causes sever diarrhea in puppies, kittens & piglets; rarely seen in adults
-has a thin cyst wall with a central mass -transmitted directly from ingesting sporulated oocysts from the environment or indirectly by ingesting cysts in prey animals (mice, etc) -cats are mainly infected indirectly -sexual & asexual reproduction in host's intestines -unsporulated oocysts are shed in fec |
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Toxoplasma
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-definitive host is the cat but can occur in all animals & humans
-ZOONOTIC -transmitted by ingesting sporulated oocysts -prepatent period is 5-24 days |
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3 infectious stages of toxoplasma
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-spororzoites: in oocysts, shed in feces
-tachyzoites: active multiplying stage; is in tissues -bradyzoites: slow multiplication stage; enclosed in cysts in tissues |
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Cryptosporidium
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-found in dogs, cats, ovines, swines, avians, guinea pigs, snakes, mice, humans
-is in the small intestines: parasitizes mucosal cells of small intestines & inflames the cells -in some cows, snakes & mice it parasitizes the stomach & abomasum -transmitted by ingesting oocysts -diarrhea may be only symptom: severe painful watery diarrhea |
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Sarcocysts
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-dogs & cats, parasitizes small intestines
-transmitted by ingesting muscle meat of horses, pigs, ruminants -sporulated oocysts are passed in feces -each oocyst contains 2 sporocysts & each of them contains 4 sporozoites -oocyst excyst, go through asexual reproduction then encyst into muscle tissue |
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Eimeria
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-affects ruminants
-parasitizes cecum & colon -transmitted by ingesting oocysts -many different eimeria species & is difficult to identify species oocysts since they are similar in size & shape |
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Eimeria bovis
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-oval shaped
-micropyle -Apicomplexans -unicellular -affects cattle -parasitizes digestive tract causing diarrhea |
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Babesia common name?
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Texas Fever
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Characteristics of Babesia
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-affects bovine mainly, but can infect any domestic animal
-transmitted by the bite of infected hard tick -parasitizes RBC erythrocytes, damaging the cell; leads to anemia, fever, icterus -damages cell because it keeps reproducing within the cell until the cell wall erupts, leaving the organism to invade other RBCs -symptoms are fever, depression, icterus, anorexia, hemoglobinuria, pale mucous membranes, weakness, splenography -if diagnoses, state & federal authorities must be notified |
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Plasmodium "Avian malaria"
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-affects avians
-starts in organs like the liver & spleen, causing inflammation; then invades RBC, causing a signet ring: displacement of RBC nucleus, ultimately destroying RBC & causing anemia -transmited by bite of infected mosquito |
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Leucocytozoon "Avian Malaria"
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-affects raptors
-parasitizes WBC -transmitted by the bite of infected black fly -is fusiform or spindle shaped -organism distorts shape & appearance of WBC |
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Haemopoteus "Avian malaria"
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-affects cockatoos, green-wing macaws, some species conures
-transmitted by the bite of affected Culicoides or Chrysaps fly -organism in RBC, appears as a bluish sausage shaped body in cytoplasm -rarely associated with clinical disease but can destroy RBCs if there is anemia -can cause death |
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Spirocerca lupi
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-esophageal roundworm (nematode)
-affects cats & dogs -transmitted by ingesting egg of intermediate host the dung beetle -forms nodules on esophageal wall which can lead to obstructions -may also cause granulomas or nodes in stomach wall -adult worms live deep inside the nodules in deep tunnels & expel their eggs through fistulas on the nodules -thick shelled eggs are passed out in feces; eggs contain larvae when laid -larvae are paperclip shaped -prepatent period is 6 months -nodules in aorta can burst & cause sudden death |
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Physoloptera
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-stomach roundworms of dogs & cats
-transmitted by ingesting egg -intermediate hosts are crickets, cockroach & beetle -worm firmly attached to lumen of stomach or small intestines or more commonly the stomach mucosa -attachment sites may continue to bleed after worm detaches -adult worms 1.3 to 4.8cm long & in vomit can be described as looking like spaghetti -eggs are small, smooth, thick shelled & embryonated when passed in feces -prepatient period 56-83 days -can cause vomiting,"", anorexia & dark tarry stools (due to blood in feces) |
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Toxocara canis, T.cati, Toxocaris leonina
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-affects dogs & cats
-transmitted by ingesting eggs with infective larvae -these are ascarids which are large roundworms -affected puppies & kittens have a very potbellied appearance -3 to 18 cm long & when passed in feces they are very tightly coiled -adult worms don't attach as undulating motion keeps them in the intestines, but can swim to stomach causing vomiting -looks like spaghetti in vomit -eggs are unembryonated, spherical, deeply pigmented center with rough, pitted outer shell EXCEPT T. leonine: spherical-oval with smooth outershell & hyaline central portion -people become infected by ingesting eggs from soil or from contaminated hands |
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Ancylostoma caninum & A. braziliense
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-hookworms of dogs and cats
-transmitted by ingesting egg, transdermally or transmammary -worms have hooks located on their front to attach to small intestine mucosa -as worm sucks blood, it secretes anticoagulant from mouth causing feeding sites to bleed continuously after the worm detaches; they change feeding sites continuously -causes anemia, which is severe in kittens & puppies -blood is passed out in host feces, causing black tarry feces -causes serious problems in kennels & catteries |
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Reproduction of A. caninum & A. braziliense
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-male & female worms attach to adjacent villi of intestinal wall & mate continuously so female is always laying eggs
-eggs contains morula stage -in external environment eggs embryonate to L1 larvae -L1 hatch, grow, feed & molt to L2 -L2 repeats process to L3 -L3 is infective & doesn't shed its L2 cuticle & don't feed -larvae are ingested or penetrate intact skin -migrate through tissues to lungs where they are coughed up & swallowed to intestines |
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Strongyloides Stercoralis & S. tumiefaciens
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-intestinal threadworms affecting dogs, cats & humans
-transmitted transdermally & mammary milk -only female are parasitic: females produce via ova without male fertilization: parthenogenesis -eggs attach in intestines & release L1 larve; free living until until infective L3 -causes migratory damage to hosts -worms have rhabditiform esophagus, club shaped anterior corpus, narrow median isthmus & caudel bulb -prepatent period 8-14 days -causes moderate-severe diarrhea -especially problematic in kennels during summer months |
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Trichuris vulpis, T. campanula, T.serrata
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-whipworms that affect dogs (T.vulpis) & cats (T.campanula, T. serrate)
-transmitted by ingesting eggs -common in dogs, rare in cats in North America -worm resembles a whip: thin, filamentous anterior end with thick posterior end -eggs are trichuriod or trichinelloid: thick yellow-brown, symmetrical shell with polar plug on each end; resembles a football -eggs are unembryonated when laid, pass out in feces every 3 days -prepatent period 70-90 days -adults attach to cecum & suck blood -in environment eggs develop to L2 infective larvae in egg & hatches in intestine when ingested -goes through several molts before becoming an adult -symptoms are diarrhea, anemia, mucous coated stools, weak, dehydrated, poor body condition & not alert |
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Dirofilaria immitis
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-heartworms of dogs, cats, ferrets & incidential in humas
-intermediate host is the female mosquito; microfilariae grow & molt in mosquito until they are infective; enter host when mosquito bites them -worms reside in right ventricle, pulmonary arteries & fine branch arteries -cats infected spontaneously cure themselves -microfilaria are the offspring -can also be found in brain, anterior chamber of the eye & subcutaneous sites -larvae grow & molt through various body tissues on the way to the heart |
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D. immitis damage
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- damage to the heart causes most of the symptoms
-reduced blood flow to right side of the heart & inflamed lining of the blood vessels -reduced exercise tolerance -right side heart enlarged -abdominal ascites |
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D. immitis occult infection
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host is infected without larvae in the blood stream; all worms are the same sex or only immature worms are present
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Aelurostrongylus abstrusus
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-feline lungworms that reside in respiratory bronchioles & alveolar ducts, forming nodules that are small egg nests
-transmitted by ingesting larvae -prepatent period -females lay embryonated eggs that are forced into lung tissue; hatch to 1st stage larvae; larvae are coughed up & swallowed to be passed out in feces -tails have an S bend with a dorsal spine |
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Filaroides osleri
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-canine lungworm that reside in the trachea
-transmitted by ingesting infected L1 larvae: makes them unique among nematodes for being infective L1 -larvae are 232-266 um long with short S shape in tail -adults cause wart looking nodules in airway walls, usually at bifurcati9on of trachea, causing obstructions that are easily identified at necropsy -prepatent period is 10 weeks |
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Eucoleus aerophilus
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-respiratory capillarid of cats & dogs
-transmitt4ed by ingesting ova from fees or mucoid discharge -parasite resides in bronchi & trachea -prepatent period is 40 days -eggs are broad barrel shaped, light in color & have a rough outer surface with a netted appearance |
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Dioctophyma renale
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-canine giant kidney worm
-transmitted by ingesting infected larvae in an annelid -typical in the right kidney -largest nematode known & is very bright blood red in color -worm ingests the parenchyma (kidney tissue), leaving the capsule of the kidney -eggs are shed in the urine the ingested by annelid worm where they mature to infective larvae -eggs are barrel shaped, bipolar, yellow-brown colored & shell is pitted looking -known as the great wanderer as it gets off course frequently during migration to the kidney: may occur freely in peritoneal cavity |
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Pearsonema plica & P.feliscati
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-bladder worm of dogs (plica) & cats (feliscati)
-reside in the urinary bladder -transmitted by ingesting L3 infective intermediate host, the earthworm -eggs are found in the urine, & are clear to yellow colored, flattend with bipolar plugs, rough outer surface |
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Gongylonema pulchrum
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-esophageal worm of sheep, cattle, pigs, goats & horses
-live in submucosa & mucosa esophagus -intermediate host is dung beetle or cockroach & is transmitted when they are ingested -eggs laid in unique zigzag pattern in tissues |
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Trichstrongyles
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-7 species infect cattle, sheep, goats
-affects abomasmum, small & large intestines -transmitted by ingesting infective ova -all 7 species have oval, thin shelled eggs that contain a morula with 4+ cells; difficult to identify species & then with fecal culture |
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Strongyloides papillosus
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-intestinal threadworms of cattle
-infect small intestines -transmitted by ingesting infective larvae or larva penetrates the skin -only female worms are infective & produce larvated eggs -threadworms have rhabdiform esophagus -eggs grow & molt as they pass through feces; larva then become free living adults or infective stage female larvae -larvae migrate to lungs through circulatory system, coughed up then swallowed -prepatent period is 5-7 days -light infection may be asymptomatic but heavy infection can cause diarrhea, anorexia, blood & mucous in feces, weight loss |
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Trichuris ovis
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-whipworms in cattle, sheep, goats
-transmited by infective ova -parasite resides in cecum & colon -eggs are trichinelloid or trichuroid; yellow-brown symmetrical shell with polar plug at both ends -symptoms are dark feces, anorexia, anemia |
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Elaeophora schneideri
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-arterial worms of sheep
-commonly in carotid artery until it becomes obstructed then microfilariae are restricted to the skin capillaries for forehead & face -microfilariae are 270um long by 17 um thick; round blunt end anteriorly & tapered posterior -causes filarial dermatitis on face, pool region & feet |
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Dictocaulus species
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-D. viviparous: cattle
-D. filarial: sheep & goats -lungworms that reside in the bronchis -prepatent period varies between species, but is about 28 days average -female worms lay eggs in lungs, then eggs are coughed up & swallowed to be passed out in feces; eggs hatch in intestines -D. filarial microfilariae have brown food granules in their intestinal walls -transmited by ingesting L3 infective larvae: they follow circulatory system to lungs where they mature to adults -adult worms are white with small buccal cavity; short, dark granular spicules with vuvla in the center of their body |
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Muellerius capillaris
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-hair lungworms of sheep & goats
-reside in bronchioles -transmited by ingesting infective larvae -adults form nodules in lung parenchyma where they can obstruct the bronchioles -worms are 200-300 um long with undulating tip & dorsal spine |
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Habronema microstoma, H. muscae, Draschai megastoma
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-roundworms of stomach mucosa in horses
-larvae may cause "summer sores" parasitized skin lesions of cutaneous habronemiasis/draschiasis -H.microstroma & H. muscae are in the mucosa of the stomach, just beneath the thick layer of mucus -D.megastoma for large, thick fibrous nodules within the stomach mucosa -intermediate host is the muscidae fly, where parasite develops to L3 infective stage & fly deposits larvae into skin wounds -prepatent period is 60 days -symptoms occur with heavy infection & are gastritis, colic, diarrhea |
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Parascaris equorum
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-equine roundworm of the small intestines in young foals
-transmited by ingesting infective ova -is the largest equine nematode: up to 50cm long & sometimes are passed in the feces -eggs are passed in feces & are sticky; are round-oval with thick shell that is deeply pigmented & a fine granular surface -larvae grow & molt in the egg; egg contains L2 larvae when ingested by foal & hatches in the intestines -circulatory system carries larvae to lungs, where it is coughed up & swallowed -adult worms suck on blood in intestines with their distinct lips -asymptomatic unless heavily infected:unthriftiness, depression, anorexia, colic, cough & nasal discharge, pot-bellied looking |
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Strongyles vulgaris
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associated with thrombi in anterior mesenteric arties of horses
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Strongyles species in horses
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-2 types: large or small
-worms are in the large intestines -infective stage larvae migrate on blades of grass until equine ingests it -larvae migrate through intestines to mesenteric arteries & liver where they grow & molt to next stage -in the large intestines they enter the mucosa & mature to adults -symptoms are colic, weight loss, lethargy, fever & poor appetite |
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Strongyloides westeri
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equines intestinal threadworms
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Oxyuris equi
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-equine pinworms
-found in cecum, colon, rectum -transmited by ingesting infective ova -adult worms protrude from anus where females attach eggs to exterior anus with a sticky substance that causes inflammation & pruritus (itchiness) -eggs rub off on waterers, feeders, fences -eggs are operculate, slightly flat on one side -prepatent period 4-5 months -dx with cellophane tape prep |
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Habronema lesions "summer sores" appearance
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-aka cutaneous habronemiasis or cutaneous draschiasis
-lesions are various sizes with an uneven surface of soft red-brown material & covering mass is a firm, granulated tissue -wounds typically on legs, withers, male genitiaolia, medial cathus of eye -wounds get bigger & don't respond to normal treatment until following winter then they heal spontaneously |
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Onchcerca cervicalis
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-equine fiarial worm that lives in ligamentum nuchae & microfilariae in dermitis
-causes recurrent dermatitis & periodic opthalmia -transmited by no-see-ums (Culicoides species) -intermediate host are biting midges -adults live in ligamentum nuchae where females produce microfilariae that migrate to dermis through the connective tissue -microfilariae causes lesions called cutaneous onchocerciasis, which are patchy alopecia, scaling on head, neck, shoulders & ventral midline -lesions cause intense puruitus, inflammation -unsheathed microfilariae cause opthalmia & blindness |
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Ascarops stronglylina, Physocephalus sexalatus, Hyostrongylus rubidus are?
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nematode stomach worms of swine
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Trichostrongylus axei are?
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nematodes in swine stomach but also affect cattle, sheep & horses
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Strongyloides ransomi are?
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intestinal threadworms of swine where only the females are parasitic
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Oesophagostomum dentatum are?
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aka nodular worms of the large intestines of swine
-the larval stage creates large nodules within the wall of the large intestines |
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Trichuris suis are?
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swine whipworms in the cecum & colon
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Trichinella spiralis are?
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-trichina worm of the swine small intestines
-larvae also in the muscles -causes nausea, vomiting, anorexia & diarrhea -zoonotic |
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Metastrongylus elongatus
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swine lungworm that resides in bronchi & bronchioles
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Stephanurus dentatus
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swine kidney worms & is in the kidneys, ureters & tissue surrounding the kidneys
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Hymenolepis nana & H.diminuta
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-rodent tapeworm of mice, rats, gerbils, hamsters, dogs & humans
-in the small intestines -are small slender tapeworms -the worms hexacanth enters villus of small intestine & matures to nontailed cysticercoid which returns to the lumen of the small intestines & matures to adult |
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Monieza species
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-ruminant tapeworm of cattle, sheep & goats
-M.benedini: cattle M.expansa: cattle, sheep, goats -intermediate host is grain mite, which becomes infected by ingesting hexacanth embryo -up to 6 m x 1.6cm wide -proglottids are short & wide with 2 sets laterally located genital organs & associated pores -eggs are square or triangular & contain pyriform apparatus -prepatent period 40 days -larval stage is called metacestode & is in oribatid grain mite, where it develops to cysticercoid stage -one cysticercoid=1 tapeworm |
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Thysanosoma actinoides
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-fringed tapeworm of sheep, goats & cattle
-reside in lumen of bile ducts, pancreatic ducts, small intestines & can cause obstructions -proglottids are very short with fringe on posterior aspect -eggs are in packets of 6-12 eggs -intermediate hosts are psocids: primitive insects in vegetation |
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Anoplocephala & Paranoplocephala species
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-equine tapeworms of horses that are in the small & large intestines
-proglottids are wider than long, each with male & female sex organs -prepatent period 28-42 days -grain mites infected when they ingest hexacanth embryo, then the horse is infected when ingesting mite filled grain -eggs of all species have a 3 layered shell with the inner most lining being a pyriform apparatus & can visualize hexacanth embryo inside egg |
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Dipylidium caninum
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-double pored or cucumber seed looking
-tapeworm of dogs & cats -intermediate host is flea, which normally contain infective cysticercoid stage larvae -adults can be up to 50 cm -adult scolex is armed with prominent proboscis covered with rear facing thorn like hooks; lateral pore along midpoint along each of their long edges -gravid proglottids have thousands of egg packets with 20-30 hexacanth embryos in each packet -prepatent period is 14-21 days |
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Taenia saginata
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beef tapeworm
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Taenia solium
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pork tapeworm
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Taenia pisiformis
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rabbit tapeworm; can affect dogs
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Taenia hydatigena
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ruminant tapeworms; can affect dogs
-tenuicolis stages appears as a ping pong ball size fluid filled bladder attached to omentum or abdominal organs |
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Taenia ovis
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sheep tapeworm; can affect dogs
-larval stage is fluid filled bladder in the muscles |
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How can Taenia saginata & T. solium infect humans?
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by eating infected meat that is not cooked properly
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Taenia species
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-adults live in small intestines & a heavy infection can cause obstructions
-adults have armed scolex with 2 rows of rostal hooks -fresh proglottids have 1 lateral pore midpoint of long edges -proglottids contain hexacanth embryo with embryophore; striated eggshell & have 6 hooks in interior of egg -eggs are oval, with oncosphere: the growth sphere released by ingesting eggs; has 3 pairs of hooks |
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Multiceps species
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-coenurus producing tapeworms of dogs
-intermediate hosts are sheep (M.multiceps) and rabbits (M.serialis) -both species of eggs have single oncosphere with 3 pairs of hooks & scolex with a double row rostellar hooks -larval stage is a single, large bladder with several invaginated scolices attached to the inner wall; embeds in host's tissues -1 coernurus=many tapeworms |
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Mesocestoides species
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-is the only true tapeworm to use 2 intermediate hosts: the oribatid mite & rats/mice
-have unarmed scolex with 4 suckers; oblong; central uterine pore -single oncosphere with three pairs of hooks -striated embryophore -cysticercoid develops to trathyridium: a solid body metacestode with deep invaginated, acetabular -asexual reproduction -gives definiative host pot belly appearance |
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Echinococcus species
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-unilocular hydatid tapeworm
-intermediate host are sheep, cattle, herbivores (E.granulosus); rats, mice,voles (E.multilocularis) -affects cats & dogs -very zoonotic: must use PPE -eggs have single oncosphere with 3 pairs of hooks -E.granulosus causes unilocular hydatid cysts with a thick cyst wall & thin germinal membrane on the inside; membrane has brood capsules that have protscolices budding out -E.multilocularis causes multiocular hydatid cyst on liver or in lungs: looks like a bunch of grapes; has thin germinal membrane with brood capsules that have protoscolice buds |
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What are the 2 orders of lice?
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Mallophaga: biting lice
Anoplura: sucking lice |
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Mallophages morphology
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-yellow with large round head
-dorsoventrally flat & wingless -bodies are divided into 3 parts: head with mouth & esophagus, thorax with three pairs of legs & abdomen -mouths are mandibulated -head is wider than the widest part of the thorax -affect birds, dogs, cats, cattle, sheep, goats, horses -eggs are called nits: tiny, oval & white |
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Anoplura
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-larger than Mallophages
-red to grey depending on how much blood they have digested -same three body divisions as Mallophages -have pincher claws to grip host's hair -do not parasitize birds or cats -can cause anemia in host -eggs are called nits: tiny, oval & white |
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Ctenocephalides felis
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-cat fleas infect cats & dogs
-only the adults are parasitic -eggs are laid on the ground; larvae hatch & feed on skin debris; then spin cocoon to pupate |
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Sarcoptidae
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-sarcoptiform mites
-entire life cycle is spent on the host & mate on the skin surface -female burrows into skin & lays eggs in created tunnel, then the female dies -6 legged larva hatch & exit through same tunnel to skin surface -larvae molt to 8 legged nymphal stage then develop into adults *important species are Sarcoptes, Notoedres, Cnemidocoptes, Trixacarus |
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Sarcopteo scabei
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-scabies mite
-more common in dogs (canus variety) & pigs (suis variety) -lesions on pigs are small red papules with hair loss, crusts on trunk & ears -lesions on dogs cause popular rash with scaling & crusting; commonly on ears, lateral elbows & abdomen -adult mites are oval, have 8 legs, anal opening, long unjointed pedicel with sucker on end of some legs -dx with skin scrape |
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Are scabies zoonotic?
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-yes, they are spread by direct contact
-in humans it causes red bumps & blisters on arms, abdomen & trunk |
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Notoedres cati
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-feline scabies mite that infects cats & rabbits
-causes yellow crusts & severe itching, commonly on ears, back of neck, face & feet -dx with a deep skin scrape |
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Notoedres muris
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-scabies mite of rats that causes lesions on unfurred body parts
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Cnemidocoptes pilae
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-scaly leg mite of mudgerigars & parakeets
-mites tunnel through the superficial layers of the epidermis, causing yellow-grey/white lesions that look like honeycombs -causes inflammatory reaction that causes a discharge that hardens & displaces dermal scales -adult parasitic males have long, enjoined pedical with suckers at the end of each leg |
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Trixacarus caviae
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burrowing mite of guinea pigs that causes dry, scaly lesions. The result is pruritis, alopecia & dermatitis
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Psoroptidae
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mites that live on the skin surface or external ear canal & spend their entire life cycle on the host
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Psoroptes cuniculi
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-ear canker mite
-resides on external ear canal of rabbits, horses, goats & sheep causing crusty debris in the ear canal -symptoms are shaking of the head, scratching ears & a severe infestation can cause equilibrium problems |
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Psoroptes species of large animals
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-reside in thick haired or long wooled areas
-live on skin surface & puncture epidermis to feed on lymphatic fluid, causing extreme itching with crusties & wool/hair loss -a positive diagnosis must be reported to state & federal authorities |
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Chorioptes
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-foot & tail mite or itchy leg mite
-infects horses, cattle, goats & sheep -mite prefers lower hind legs & around the tail of cattle -causes thick wrinkled skin with little pruritits |
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Otodectes cynotis
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-ear mites
-transmited by direct contact & is very contagious -head shaking & scratching ears are biggest signs -severe infestations can cause middle ear disease with head tilting, circling & convulsions |
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Nonsarcoptiform mites
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do not have pedicles or stalks on legs
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Demodex
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-nonsarcoptiform mite that resides in hair follicles & sebaceous glands
-can cause hair loss & thick wrinkled skin: especially on muzzle, face & forelimbs -overwhelms puppies & dogs with poor health or inherited immune system defects |
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Chiggers
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-red to yellow mite where only the larvae are parasitic
-largest problem from late summer to early fall -transmitted by direct contact with ground or foliage -attaches to host dermis & injects digestive fluid that liquefies the host's tissue for the chigger to feed on -that digestive fluid causes severe itching -after chigger is done feeding, it falls off |
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Ticks
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-blood eating nonsarcoptiform mite
-ticks are responsible for transmitting many parasitic, bacterial, viral, rickettsial & other diseases -soft ticks have a leather like outer skin while hard ticks have bodies covered by chitinous scutum -hard ticks will engorge themselves during feeding |
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characteristics to note when examining fecal samples?
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-consistency
-color -blood present? -mucous present? -age of fecal sample -visible parasites or proglottids? |
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When/where/age of fecal sample in large & small animals
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-small animals: freshest sample possible; no more than 24 hours old & refrigerated if not bought into clinic immediately after collecting
-large animal fecal samples should be collected directly from rectum |
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procedure for direct fecal smear
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-mix a small amount of feces with a drop water or saline & place a drop on a glass slide
-can be stained with iodine to help identify organisms *this method is not a good representative of the sample as results are inaccurate |
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procedure of simple fecal float
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*second most common test performed
-place 2-5g of feces in a container -add selected flotation solution directly to feces & mix thoroughly with a tongue depressor -strain through a metal tea strainer or cheesecloth into a second container -pour the strained feces into a test tube & add flotation medium to tube until a meniscus is formed -place glass coverslip over tube & let sit undisturbed for 10-15 minutes -remove coverslip & place on glass slide to examine under microscope |
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what is specific gravity
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the ratio of given volume of a substance to weight of equal volume of another substance, usually water
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what does centrifuging a sample do?
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separates different weight substances in a sample
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What type of centrifuge should be used for flotation & what are the expected results
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-more efficient to recover eggs & cysts from fecal sample
-centrifuge must be able to hold 15 ml test tubes & produce a force of 400x-650x g -a fixed angle head is not suitable |
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procedure for fecal sedimentation
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-mix 2 g (1tsp) feces with tap water to make a semisolid suspension
-strain & place in a test tube; place in centrifuge -balance centrifuge with another test tube filled with water opposite of fecal sample: make sure tubes are marked -spin at 400x (1500rpm); if no centrifuge is available allow tube to sit undisturbed for 20-30 mins (heavier sediment will settle to bottom of tube) -pour off supernatant without disturbing the sediment at the bottom -with a pipette, remove a small amount of the top layer of sediment & place on glass slide (if too thick, add a drop of water) -add a coverslip & examine -repeat with a drop of sample from the bottom of the sediment |
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what is a fecal culture used for?
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to differentiate eggs & oocysts that can not be distinguished by examining a fresh sample
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procedure for fecal culture to identify roundworm eggs: must be a diagnostician to perform this test
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-place 20-30 g of fresh feces in a jar & add water to slightly moisten; stir with tongue depressor: do not want this mixture to be soupy
-place jar away from direct sunlight & incubate at room temperature for 7 days: should see water droplets inside the jar: if not, add slight bit more water -after 7 days remove a sample via the Baermann technique; then remove a sample off the cheesecloth with a cutoff pipette -place on glass slide & examine -some larvae will migrate up the side of the jar so remove a sample from there with a paintbrush to examine |
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procedure for fecal culture to identify coccidial oocysts: to be done when oocysts are found in fresh feces
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-place 10-20 g feces in a cup & cover with 60 ml 2.5% potassium dichromate solution; stir thoroughly with tongue depressor
-place sample in petri dish & incubate at room temperature for 3-5 days; open daily & swirl contents gently -after 3-5 days, place plate contents into test tube & centrifuge -then follow centrifugal flotation procedure |
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how to do a cellophane tape preparation
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*to diagnose equine pinworms
-make a tape loop with sticky side out & attach to a tongue depressor -stand on right side of horse & raise tail; then press tape onto skin directly around anus -place a drop of water on a glass slide then add the tape; allow water to spread out under tape -examine under microscope |
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Baermann technique procedure: to identify roundworms
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-spread a piece of cheesecloth over the support screen of the Baermann apparatus
-place 5-15 g of sample on cheesecloth: sample may be feces, soil or tissue -fold excess cheesecloth over top of the sample; then saturate sample completely with warm water or physiological saline -leave undisturbed overnight -hold a slide under cutoff pipette & open pinch clamp just enough to allow a large drop of fluid to drop onto slide; cover with coverslip -repeat procedure to make several slides to examine |
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procedure for direct blood smear & purpose
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place a drop a blood onto slide: no coverslip
*to detect movement of parasites that live outside of red blood cells |
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procedure for thin blood smear
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-place a drop of blood on the end of a glass slide
-hold another glass slide at a 35-45 degree angle & place at the edge of blood drop: the blood will spread between the two slides -smoothly & rapidly pull slide forward to make a smear with a feathered edge -air dry then stain |
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define occult infection & why it can happen
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parasitic filarial infection without the presence of microfilariae
-heartworms are too young to produce microfilariae -worms are same sex -circulating microfilariae are produced but are removed by the host -drug treating the infecting has killed the microfilariae but not affected the adults |
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define amicrofilaremic
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absent immature microfilariae
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define buffy coat & its composition
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-layer of cells that is seen above the packed red blood cells in a centrifuged blood sample
-it is composed of white blood cells, platelets; usually a red-grey color |
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what result does the buffy coat give?
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-packed cell volume
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how to diagnose parasites of the respiratory tract
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with fecal float, direct fecal smear or Baermann technique
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how to diagnose parasites of urinary system
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do not have to use sterile urine
centrifuge & examine urine sediment |
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how to diagnose skin parasites
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skin scrape
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parasitiasis
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parasite is present on or in the host & is potentially harmful but there are no outward symptoms of disease
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parasitosis
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parasite is present on or in a host & there are outward symptoms of disease as the parasite is harming the host
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mutualism
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association between 2 organisms where both are mutually benefited
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commensalism
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association between 2 organisms where one is benefited & the other is neither harmed or benefited
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ectoparasite
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parasite lives on the body of the host
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endoparasite
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parasite lives in the body of the host
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errant/aberrant parasite
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parasite wanders from its usual site of infection to a place it doesn't normally live in
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incidental parasite
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parasite occurs in a host it doesn't normally live
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facultative parasite
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parasites that are free-living (nonparasitic) in nature that become parasitic in certain hosts
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obligatory parasite
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parasite not capable of surviving without living on a host
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periodic parasite
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parasite that intermittently visits host to obtain nourishment or other benefits
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zoonosis
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any disease or parasite transmissible from animals to humans
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definitive host
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the animal harboring sexually mature parasites
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intermediate host
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where immature parasite mature other than the definitive host
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transport or paratenic host
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special type of intermediate host where no maturing of parasite takes place; it remains encysted in the tissues & remains there until the definitive host eats the transport host which awakens parasite & it will grow
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indirect life cycle
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parasites that require an intermediate host
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life cycle of D.immitis
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-adult female dirofilaria immitis parasite releases microfilariae into host's blood
-the intermediate host mosquito ingest microfilariae with blood meal -microfilariae develop in the mosquito to infective larvae -mosquito bites the host (cat or dog) & transmits infective larvae |
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direct life cycle
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parasites that reproduce without an intermediate host
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prepatent period
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time period from entrance to infective stage to reproductive maturity
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Sheather's solution
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is a sugar flotation solution used as a flotation solution that does not distort roundworm eggs; it is less effective than sodium nitrate solution because it floats less eggs
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Sodium nitrate flotation solution
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contains about 31.5 g of sodium nitrate for every liter of water; it is the most effective solution but tends to forms crystals & does distort eggs after a time
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purpose of using flotation solutions
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when the solutions have a specific gravity between 1.2 - 1.25 it will cause parasite eggs to separate from feces & float to the top of the liquid & heavier fecal particles to sink to the bottom
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saturated sodium chloride solution
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composed of sodium chloride (table salt) in water & is the least desirable solution to use because it corrodes expensive lab equipment & forms crystals on the microscope slide. its specific gravity of 1.2 doesn't always allow heavier eggs to float
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zinc sulfate solution
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has a similar efficiency as Sheather's solution & is excellent for diagnosing intestinal protozoans
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magnesium sulfate solution
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a solution made from Epsom salt; it is an inexpensive solution that is easily used
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Most common diagnostic test
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fecal flotation
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the Baermann technique is used to primarily identify what parasite?
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lungworm larvae
the warm water encourages the larvae to move out of the feces |
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the most common & important parasite identified in the blood?
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Dirofilaria immitis
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the thinnest part of a blood smear is called?
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the feathered edge
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what can be identified with a stained thin blood smear?
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-microfilariae
-some protozoans within the red blood cells -rickettsiae on the red blood cell surface *unless parasites are present in large numbers, they may not be observed |
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approximate percent of dogs with heartworm disease that don't have microfilariae circulating?
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25%
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Other reasons to use cellophane tape preparation?
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to diagnose lice & mites that live on skins' surface. the tape is viewed under microscope with mineral oil
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important flagellates of domestic animals
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Leishmania, Trypanosoma, Trichomonas, Histomonas & Giardia
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important amoebaes of domestic animals
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Entamoeba histolytica
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important ciliates of domestic animals
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Balantidium
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hemoprotozoan
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blood born protozoa
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Describe the mutual benefit of nonpathogenic ciliates with the rumen in cattle?
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While the cow provides a warm environment for the ciliate & the ciliate helps cattle digest cellulose from the plants they eat
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Describe Coccidian life cycle from beginning to end
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1. infective stage in the environment: the oocysts contain sporozoites
2. oocyst is ingested by the host 3. sporozoites enter intestinal epithelial cells 4. sporozoites the develop to merozoites 5. merozoites reproduce asexually until the host cell dies 6.merozoites enter new intestinal epithelial cells & some asexual reproduction occurs 7. merozoites develop into microgametes & macrogametes 8. they develop further into sporozoites 9. the sporozoites secrete a sporocyst 10. oocysts are passed out in feces |
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coccidiosis
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infestation of the alimentary canal by protozoans of the order Coccidia that causes diarrhea, sometimes bloody diarrhea
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hemolytic anemia
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anemia caused by destroyed erythrocytes
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important coccdians of domestic animals
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Eimeria, Isospora, Sarcocystis, Toxoplasma & Cryptosporidium
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important hemosporidian parasites
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Plasmodium, Haemoproteus, Leucocytozoon & Babesia
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intermediate host of Leishmania
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phlebotomine sand flies
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How is Leishmania confirmed?
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histopathological sections of infected organs
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Diagnosing & confirming Trypanosoma
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-diagnosed through direct blood smears
-confirmed by histopathological sectioning of suspected tissues looking for cystic amastigotes |
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Trichomonas appearance
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-pear shaped
-3 to 5 flagella on the front end - 1 or more trailing flagella on hind end |
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2 morphological forms of Giardia
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-trophozoite: feeding stage; lives in the intestines; flattened pear shape with 4 pairs of flagella; cell has 2 nuclei
-oval cyst stage: is resistant to the environment & is responsible for transmission & survival outside of the host |
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life cycle of Giardia
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-direct life cycle
-once cysts are ingested, the trophozoites are released & attach to the epithelium of the small intestines -they develop to cysts which are expelled from the body in the feces |
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Where in hosts body do parasitic flagellates live?
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in fluids: blood, lymphatic fluid, cerebrospinal fluid
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What two types of nuclei do ciliates possess?
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macronucleus & micronucleus
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