Parasitology 4 Flashcards
Dictyocaulus viviparus what is it, effect on host
Lungworm of cattle
• major pathogen of cattle particularly young calves
• cough, laboured breathing and difficulty walking
• hypersensitivity type 1 reaction
• Adults generally subclinical and act as carriers for young calves
○ develop strong immunity
Dictyocaulus arnfieldi what is it, location and effect on host
Lungworms of equines
- in trachea
only mildly pathogenic
Parelaphostrongylus tenuis what is it and effect on host
Lungworm of deer
No clinical signs with deer
- in abnormal host (cattle, sheep, moose -> produce fatal neurological disease
Parelaphostrongylus tenuis what is it and lifecycle
Lungworm of deer
- eggs laid in cranial venosus sinuses
- Eggs carried to lungs and hatch
- larvae enter alveoli & reach faeces
- L1-L3 develop in snail
- L3 ingested via ingesting infected molluscs
- L3 migrates through abomasal wall to abdominal cavity
- follow nerves to spinal cord
- migrate up spinal cord to subdural space
- Moves to predilection site -> cranial venous sinus
- Undergo moult there and become an adult
Elaphostrongylus cervi what is it, location and effects n host
Lungworm of deer
- snail intermediate host
No clinical signs in normal host
Neurological signs in other ruminants around deer
Aelurostrongylus abstrusus what is it, host, location features and effects on host and which lifecycle
Lungworm of cats Features: • tiny nematode, in alveoli • very common parasite in southern parts of the country, common within cats Effect on host: • generally subclinical • mild cough • weight loss • eosinophilia INDIRECT - slug or snail as intermediate with cats as paratenic host
How to diagnose lungworm infection, 2 ways and describe
1) Baermann technique
The Baermann technique is based on the active migration or movement of larvae.
1) Faeces are suspended in water.
2) The larvae move into the water.
3) They sink to the bottom and can be collected for identification.
2) Larvae with distinct morphology
Metastrongylus apri, salmi, pudendotectus what are they, location lifecycle and effect on host
Lungworm of pigs
Location - bronchi
Lifecycle - Indrecti - intermediate is earthworm which pigs then ingest (L3)
Effects on host
- respiratory airway disease, obstruct airway
- transmit swine influenza virus
Angiostrongylus vasorum what is it, host, location, feature, lifecycle, PPP, clinical signs
Lungworm of dogs - pulmonary artery Barbers pole appearance! Lifecycle - indirect, snail as intermediate host PPP = 4-8 weeks Clinical signs • mild, cough, interstitial pneumonia; • severe cases develop heart failure - Right sided congestive heart failure
Oslerus osleri what is it, host, location, lifecycle, PPP, effects on host
Lungworm of dogs nodules within the trachea DIRECT 1) L1 (infective phase) passed in faeces 2) L1 ingested 3) L1 regurgitated with food & water 4) larva penetrates duodenum 5) migrates to lung (all moults occur) then trachea (predilection site) PPP about 18 weeks Effects on the host • very common in dingoes • clinical signs of airway obstruction
Filaroides hirthi what is it, host, location, lifecycle, effects on host
Lungworm of dogs tiny worm in alveoli Life cycle: DIRECT • L1 passed in faeces Effects on the host: • infection usually inapparent • grossly nodular lesions on the surface of the lungs • fatal with intercurrent disease
Angiostrongylus cantonensis what is it, host, location, clinical signs
Lungworm of rats
Location - pulmonary arteries
Effects on hosts
• NO clinical signs in rats
• in abnormal hosts (dogs, cats, horses, zoo animals) causes severe encephalitis
○ Cause of eosinophilic meningitis in man
Angiostrongylus cantonensis what is it, lifecycle
Lungworm of rats
Lifecycle: INDIRECT LIFECYCLE
1) L1 released into blood stream
2) breaks into alveoli -> coughed up and swallowed -> passed in faeces
3) L1-L3 in snail or slug, prawns and land crabs
4) rat eats snail or slug (do not have to eat L3 can be shed on leaves)
5) larva enters blood stream, migrates to CNS
6) moults to L4 in anterior cerebrum
7) enters venous system and migrates to pulmonary artery (predilection site)
Give 6 characteristics of anthelmintics
1) Spectrum of activity
2) administration
3) safety margin
4) selective toxicity
5) withdrawal period
6) economical
What are the 3 tests for evaluating the efficacy of an anthelmintic
1) Faecal egg count reduction test (FECRT) -> Select animals with worms and treat with anthelmintics and other without
○ Compare pre and post-treatment egg counts -> if effective should reduce egg count by 95%
2) controlled test: control and treated groups -> - Have group with anthelmintics, another group used as negative control, after treatment slaughter all the animals and count the number of worms
○ Most effective test and mainly used for ruminants
3) critical test: treated animals act as controls
- Select animals infected with parasites, treat them and collect faeces for 5-7 days look for presence of faeces, then slaughter and faecal egg count of the animals
What drug inhibits tubulin formation
- Benzimidazole
What drugs act on the nervous system
- Levamisole, morantel, pyrantel, ML, organophosphates, piperazine