Lecture Quiz 3 - Exam 1 - Nematodes - Metastrongyloidea

Front 1

What are the features of metastrongyles?

Back 1

Adults are in respiratory, vascular or nervous systems.

Males usually have a bursa but it is often reduced or absent and the spicules are highly variable in size and shape.

Females are oviparous or ovoviviparous, but L1 or egg with L1 shed in feces

No buccal cavity; small mouth

INDIRECT life cycle with gastropod IH

Front 2

What lung worms are present in each species?

Back 2

Small ruminant lungworms: Protostrongylus and Muellerius

Swine lungworm: Metastrongylus spp.

Dogs:
Oslerus osleri - tracheal worm
Filaroides spp and Crenosoma - lungworms

Feline lungworms: Aleurostrongylus

Cervids: Parelaphostrongylus tenuis - meningeal worm

Front 3

What are the lungworms of ruminants?

Back 3

1. Superfamily Trichostrongyloidea: Dictyocaulus spp
Largest lungworm in upper airways
(in cattle, small ruminants, cervids, camelids)

2. Superfamily Metastrongyloidea: Protostrongylus spp - smaller; in bronchioles, alveoli and parenchyma
Muellerius - hair lungworm; smallest: in alveoli
(both in small ruminants, not in cattle)

Front 4

Indirect life cycle of Protostrongylids (Protostrongylus and Muellerius)

Back 4

L1 in fresh feces --> L1 infects intermediate host (snails and slugs) --> Develops to L3 in intermediate host --> Infection acquired by ingesting IH

Front 5

Describe Protostrongylus spp.

Back 5

1. Adults: in bronchioles, alveoli, lung parenchyma; approximately 2-4 cm long
2. Prepatent period: ~ 1 month
3. Patent period: 2 years
4. Transplacental transmission of larvae of fetal liver: after birth, larvae migrate from liver to lung

Front 6

Define Protostrongylus rufescens.

Back 6

Red lung worm
1. Domestic small ruminants
2. Adults reddish-brown when fresh
3. Males 16-28 mm long
4. Females 25 - 35 mm long

Front 7

What are the lesions and signs of Protostrongylus spp?

Back 7

1. Local inflammation + exudate in lung tissue distal to adults in bronchioles

2. Desquamation of epithelium (alveoli, bronchioles): occlusion of blood vessels and CT proliferation

3. Result: lobular pneumonia: conical yellow-grey, possible localized fibrinous pleuritis

4. Usually sub-clinical

Front 8

What is the diagnosis of Protostrongylus?

Back 8

1. Baermann on fresh feces to detect L1
2. Long tapered, sharply pointed posterior end

Front 9

What is the treatment of Protostrongylus?

Back 9

1. Levamisole
2. Extra-label: Benzimidazoles and Ivermectin (very effective against P. rufescens)

Front 10

Describe Muellerius spp.

Back 10

1. Hair lungworm of small ruminants
2. Adults: tiny, fine white worms
Males: 12-14 mm with tiny bursa + spiral tail
Females: 19-23 mm
3. Occur deeply embedded in lung tissue
Adults, eggs and L1 occur in lungs
Only see clinical signs in heavy infection
4. Indirect life cycle: land snails serve as intermediate host

Front 11

What is the life cycle of Muellerius spp?

Back 11

1. Adults in alveoli, sub-pleural granulomas: L1 hatch from eggs in lungs --> L1s coughed up, swallowed, passed in feces

2. L1 enter snails and develop to L3: snail with L3 ingested by new host and L3 migrates to blood, heart and lungs

Prepatent period: 4-6 weeks
Patent period: 5-6 years

Front 12

What are the clinical signs of Muellerius spp?

Back 12

1. Usually asymptomatic
2. Heavily infected host can develop: bronchopneumonia, cough, fibrinous pleuritis
3. Pneumonia often due to secondary infections: M. capillaris in goats can cause severe clinical interstitial pneumonia

Front 13

What are the lesions of Muellerius spp?

Back 13

1. Sub-pleural granulomatous nodules
2. < 2 cm, grey-green grossly visible on lung surface
3. Young nodules contain adults, eggs and L1
4. Older nodules often calcified and contain no parasites
5. Can diagnose @ necropsy + parasite

Front 14

What is the treatment of Muellerius?

Back 14

1. Extra-label
2. Efficacious anthelmintics: Benzimidazoles, Levamisole, and Ivermectin

Front 15

Describe Dictyocaulus filaria.

Back 15

1. Protruding protoplasmic knob on head
2. Many dark food granules in intestinal tract
3. Tail ends in blunt point

Front 16

What are the swine lung worms?

Back 16

Superfamily Metastrongyloidea:
1. Metastrongylus apri
2. Metastrongylus pudendotectus

Front 17

What is the Metastronglus structure?

Back 17

1. Adults: white, ~2 inches long with 6 lips around the mouth; male has reduced (small) bursa

2. Eggs: colorless with thick rough shell; contain L1 when passed in fresh feces

Front 18

What is the life cycle of Metastrongylus spp?

Back 18

Adults in bronchioles lay eggs --> eggs coughed up and swallowed --> egg or L1 ingested by earthworm --> L3 develops in 10-30 days --> earthworm eaten by pig --> L3 penetrate gut wall --> lymphatics --> heart --> lungs --> alveoli --> bronchioles --> mature to adults

Prepatent period ~3-4 weeks

Front 19

What is the epidemiology of swine lung worms?

Back 19

1. Eggs resistant to environmental extremes: survive in soil for long period of time

2. L3 can live years in earthworms: can survive for several weeks in dead earthworms

Front 20

What are the lesions of Metastrongylus?

Back 20

1. Due to larvae: petechial hemorrhages in lungs

2. Due to adults: obstruction of bronchioles, verminous pneumonia, consolidation and/or emphysema

Front 21

What are the clinical signs of Metastrongylus?

Back 21

1. Not as pathogenic as ruminant lung worms: older animals relatively resistant; signs more likely in young growing pigs

2. Can have secondary infections: possible vector for swine influenza, hog cholera, mycoplasma

Front 22

What is the diagnosis of Metastrongylus?

Back 22

1. Clinical signs suggestive
2. Flotation on fresh feces: eggs with an L1; unreliable method - false negatives occur; some suggest zinc or magnesium sulfate instead of sugar solution; necropsy - adults in bronchioles

Front 23

How do you control Metastronglyus spp?

Back 23

1. Sanitation: prevent earthworms from ingesting eggs/larvae from swine feces

2. Prevent access of hogs to earthworms: raise on cement or in confinement; use nose rings to prevent rooting in soil

Front 24

What is the treatment of Metastrongylus spp?

Back 24

Fenbendazole, Ivermectin or Levamisole

Front 25

Describe Parelaphostrongylus tenuis.

Back 25

Meningeal worm, brain worm

Natural definitive host = white tail deer

Require terrestrial snails or slugs as IH

Front 26

What do adults of Parelaphostrongylus tenuis look like?

Back 26

Long (2-4 inches) and slender

Red-brown to straw-colored when fresh

Front 27

What do L1 of Parelaphostrongylus tenuis look like?

Back 27

Have dorsal spine on cuticle of tail

Front 28

If L3s of Parelaphostrongylus tenuis exit the snail/slug, can it survive?

Back 28

Can survive cold stress ( 4 degrees to 10 degrees C ) and desiccation

L3 retain motility but infectivity not determined

Front 29

Parelaphostrongylus tenuis life cycle.

Back 29

White tail deer (adults) --> L1 in environment --> Snails --> L3 --> ingested by WTD --> penetrate gut wall into peritoneal cavity --> follow spinal nerves to vertebral canal --> follow spinal nerve to dorsal horn grey matter --> develop to L4 --> exits cord into subdural space --> mature adults and mate

Front 30

How do eggs of Parelaphostrongylus tenuis travel?

Back 30

Female deposit round eggs into venous blood --> eggs carried in blood to heart and lungs --> eggs lodge in lung capillaries and develop into L1 --> trapped in granulomas --> escape --> coughed up, swallowed, pass through GI tract and exit in feces

Front 31

Pathogenesis of clinical signs of Parelaphostrongylus tenuis.

Back 31

WTD = asymptomatic

Accidentdal hosts: clinical signs result from damage to spinal cord during larval migration in parenchyma --> hemorrhagic tracts and inflammation

Most common: ataxia, hypermetria, rear limb weakness - difficulty rising or inability to rise

Front 32

Treatment of Parelaphostrongylus tenuis.

Back 32

Kill parasite with anthelmintic = fenbendazone

Minimize inflammatory response to antigens of dead parasite with anti-inflammatory

Maintain/restore function

Front 33

Structure of Oslerus osleri (tracheal worm of wild canids and dogs)

Back 33

Adults: very small (5-15 mm), slender; females are ovoviviparous

Eggs and L1: eggs thin-shelled (contain a fully-developed L1 that hatches in the host); L1 tail is short and S-shaped (kinked)

Front 34

What is the life cycle of Osleurus osleri?

Back 34

Adults: sub-mucosal nodules in trachea and bronchi NEAR TRACHEAL BIFURCATION --> eggs hatch in host --> L1 present in feces or saliva --> L1 directly infective to new host by ingestion (require no period of development outside host)

Front 35

What is the transmission route of Oslerus osleri?

Back 35

Ingestion of L1 from infected animal: from bitch to pup - regurgitative feeding (L1 coughed up and swallowed so present in stomach contents fed to pups)

Coprophagy

Front 36

What are clinical signs of Oslerus osleri?

Back 36

Verminous nodular bronchitis

Nodules obstruct airways: dyspnea, wheezing, harsh dry cough

Front 37

What are the lesions of Oslerus osleri?

Back 37

Sub-mucosal nodules in trachea and bronchi: gray, well-circumscribed, holes for females to protrude and discharge larvae

Front 38

How do you detect L1 in feces or saliva or tracheal wash?

Back 38

Zinc sulfate centrifugal flotation

Front 39

Prevention and control for Oslerus osleri?

Back 39

Very difficult to prevent transmission from bitch to offspring: deliver pups by C-section and hand-feed in isolation from other dogs

Prevent pet dogs from ingesting regurgitated food or feces from wild canids

Front 40

Describe Filaroides hirthi and milksi

Back 40

Adults occur in bronchioles and alveoli: eggs and L1 elicit granulomatous penumoa; infection usually asymptomatic

F. hirthi: do NOT have a kinked tail
F. milksi: have a kinked tail

Front 41

Describe Crenosoma vulpis

Back 41

Fox lung worm

Adults: upper airways of wild canids, dogs, and racoons; small ~16 mm; INDIRECT life cycle (gastropod intermediate); prepatent period = 19 days

Front 42

What are the clinical signs of Crenosoma vulpis?

Back 42

1. Upper resp: nasal discharge, rhino-tracheitis, bronchitis

2. Heavy infection: severe broncho-pneumonia

3. Persistent productive cough non-responsive to antibiotics - can elicit cough by tracheal palpation

Front 43

What is Aelurostrongylus abstrusus?

Back 43

Cause of feline verminous pneumonia; mainly in SE coastal states and west

Front 44

Life cycle of Aelurostrongyles.

Back 44

Adults in lung parenchyma: in "nests" or sub-pleural gray-white nodules; eggs hatch in the host; L1s coughed up, swallowed and pass in feces --> penetrates snail/slug intermediate host --> L3 develops --> ingested by host (prepatent period = 5-6 weeks)