Final Exam Review Flashcards
What parasites have to sporulate/ become embryonated outside of the host?
* Toxoplasma gondii
* Toxocara canis/ cati
* Coccidia- Eimeria & Cystoisospora
* Trichuris vulpis
What parasites are infective immediately?
* Cryptosporidium
* Giardia
* Strongyloides
Trichomonas gallinae (squabs)- upper digestive tract; nasal cavity (pigeons, budgerigars, backyard poultry, raptorial birds).
Transmission: infected parent feeding young, pigeons are asymptomatic carriers, prey meal for another bird (raptor)
* Young, immunocompromised
Diagnosis: scrape/ crop flush
Tx: ronidazole, metronidazole, surgical removal, quarantine, culling
Which compound classes are effective against juveniles of these parasites?
Niclosamide and Oxyclozanide
Histomonas meleagridis + co infection with E. coli
* Entero-hepatitis or Blackhead
* turkeys, chickens, pheasants, and other game birds
* young turkeys most vulnerable
** Earthworms
* Localized form (caeca) and systemic form (vessels- liver, spleen, lung)
* Control: Anthelmintic control (Heterakis)- benzimidazoles are for non food producing animals only
When do you treat for Fasciola in Victoria? Consider this with nematodes?
* Late winter- closantel- adult flukes- will have some efficacy against other nematodes
* Mid summer- immature flukes therefore have to use triclabendazole (highest nematode FECs)
* Could treat once more in autumn if mid summer dose was not enough to kill immature flukes– but this is also when nematode burden on pasture is high in winter rainfall zones
Control:
* spelling pastures- 2-3 months in the summer, double that in the winter
* integrative grazing- cattle and sheep
* ensure dosing appropriately– dosing too frequently and underdosing can add to resistance
* FECR test to know what drenches are effective
* Combinations of unrelated drenches, rotating drenches
What are the 4 eimeria that can be vaccinated against? Where do they hang out?
* Eimeria necatrix, E. maxima, E. acervulina, E. tenella
* Small intestine
Life cycle of Toxocara canis
Dog might ingest PH, egg, transmammary, or transplacental (where they end up in foetal liver)
* Puppy- TP- tracheal migration–>swallowed–> SI OR via TM develop straight into adults in SI
* Adult > 6 months old–> somatic migration where they encyst–> TP migration of L2s to fetal liver OR in a male end of the line
** Mouse–> goes to peripheral tissues–> dog eats mouse and larvae are in the SI to go to muscles and encyst..
Life cycle of Dirofilaria immitis. Pathogenesis?
* Mossie releases microfilariae into circulation–> moult to L4 in sub-cutis muscle 10 days later–> moult to adult at 70 days and reach right ventricle after about 3 months–> female adult worms release microfilariae into the blood
* PPP= 6 months, worms live for 5 years
* Pathogenesis: Pulmonary artery dilated and loses elasticity–> heart working extra hard–> right sided congestive heart failure–> congestion in the lungs–> cough, reduced exercise tolerance
** thrombi, caval syndrome with congestion of the liver, centrilobular necrosis and jaundice
** renal changes with thickening of basement membrane of glomeruli (immune complexes)
* zoonosis- coin lesions in lung of man
Diagnosis and treatment of D. immitis
Diagnosis: microfilariae in blood via Knott’s technique (concentrating microfilaria); must differentiate from D. reconditum; snap test but low sensitivity and low specificity
* Preventive: MLs (monthly), Curative: Melarsomine dihydrochloride
You are called to a free range poultry facility. Approximately 35% of chickens have bloody faeces, ruffled feathers and pale mucous membranes. DDX? Tests and samples?
* Coccidiosis, Capillaria annulata, Ascaridia galli
* tests and samples: faecal float, faecal smear– McMaster method for oocyst count, sporulation in 2% potassium dichromate solution + leave for 5 days, float- look for unsporulated oocysts
Control of Coccidiosis
* Clean and fresh water, ensure facilities aren’t overcrowded, ammonia based cleaners, biosecurity- quarantine, vaccination (4 Eimeria), ionophores- cocciodiostat, cannot give toltrazuril because of witholding period (potentially)
Seven day old piglets developed scours and have lost body condition in an intensive piggery, some vomiting milk. DDX?
* Cystoisospora suis, Cryptosporidium suis, Balantidium coli, Eimeria, Strongyloides ransomi
* Faecal float- looking for unsporulated oocysts, faecal smear +/-, McMaster method for oocyst count, sporulation in 2% potassium dichromate solution leave for 5 days
* Necropsy: Cystoisospora would cause dilation of intestines + histology
How is the treatment of pigs different with Coccidiosis than chickens?
* All in all out systems, quarantine maybe less necessary– ammonia cleaner essential
* also mass treatment with coccidiostats
* toltrazuril at 3-5 days of age, ensure leaves enough time for witholding period
An 8 week old puppy presents with depression, listlessness, anorexia and water diarrhoea. Dehydrated and pyrexic with sore abdomen. Dewormed with pyrantel/ febantel/ praziquantel tables regularly. DDX?
* Cryptosporidium canis
* E. coli
* Rotovirus
* Ingestion of spoiled food
* Strongyloides stercoralis (tx: ivermectin, oxibendazole)
Diarrhoes in 6 week old puppy- pasty-to-watery
- Giardia duodenalis
- Trichuris vulpis
- Strongyloides stercoralis
- Cryptosporidium canis
- Cystoisospora canis
An 8 week old puppy presents with depression, listlessness, anorexia and water diarrhoea. Dehydrated and pyrexic with sore abdomen. Dewormed with pyrantel/ febantel/ praziquantel tables regularly. Samples and tests?
* Fresh faecal sample- faecal smear + ziehl neeson stain to look for crypto, microscopy for Giardia, faecal float to look for oocysts
Removal of dog faeces from public places is an important environmental public health consideration. Explain why this is the case.
* Many parasites of zoonotic importance are found in dog faeces, some that sporulate after staying in the environment for a time, some are immediately infective, and many are resistant in the environment and will persist for a period of time
** can end up washing into the water as well and have the potential to infect by this means as well– chlorination does not take care of Cryptosporidium for example, it is also 5 microns and can escape through many different water filtration systems
* Strongyloides stercoralis- can actually kill immunocompromised patients- potential for severe illness in children
* Giardia duodenalis
* Cryptosporidium (though much more likely to pick this up from a calf)- can also kill immunocompromised
* Toxocara canis eggs are resistant in the environment- zoonotic cause of visceral larva migrans or ocular larva migrans in children who eat dirt or actual faeces
* Hookworms, Ancylostoma caninum are zoonosis– walking barefoot in the park can actually pick them up- cutaneous larva migrans
* Echinococcus can survive for years in the environment- embryonated when passed– extremely sticky and easily transferred– NO CLINICAL SIGNS IN DH (dog)
* Toxoplasma gondii- immunocompromised dogs can get it too. Can survive for 1.5 years in the environment– can kill immunocompromised humans, can cause abortion/ stillbirth/ chorioretinitis
* Children, with naive immune systems, playing on the ground- pick up oocysts, cysts, or infective stage of nematodes and put them in their mouths
* Stepping in the poop and tracking it into your home, higher likelihood of accidentally ingesting
How do you manage cryptosporidiosis in a dog?
* Warn the owner about potential zoonosis for children or immunocompromised
* Ammonia based cleaners
* Chlorine won’t work
* No curative treatment, supportive care
* POtential with hyper-immune bovine colostrum
You are presented with a 9 week old puppy that developed anorexia, vomiting and yellow pasty volumnous diarrhoea since yesterday. It has been dewormed with pyrantel/ praziquantel according to labelled instructions every two weeks since it was 2 weeks old and has had its first set of vaccinations. The owner acquired it a week ago from a breeder and the other pups in the litter appear to be fine.
* Giardia duodenalis- febantel for 3 days
* Cystoisospora canis- toltrazuril
You are called in to a property in southern NSW to investigate ill-thrift affecting ~10% of adult sheep. On closer exam of the stragglers you notice sheep are anaemic, have poor body condition and some ‘bottle jaw’
* Haemonchus contortus
* Fasciola hepatica
(5 in 1 vaccine- only prevents Black Disease with Clostridium novyi)
What are the infective stages of Cyclophyllideans non-taeniids?
Cysticercoid
What are the infective stages of Cyclophyllideans taeniids?
Cysticercus, Strobilocercus (T. taeniaeformis), Coernus (T. multiceps)
What is this farmer at risk of?
Schistosoma japonicum– portal and pulmonary hypertension, ascites, worm antigens in circulation and therefore antibody mediated glomerulonephritis, fibrosis, neoplasia, amyloidosis
** Praziquantel ; replace buffaloes with tractors
Ancylostoma caninum
Dipylidium caninum
Toxocara canis
