Protozoa - coccidia - Cystoisospora & Crytosporidium Flashcards
Lifecycle of cystisospora
Direct and host specific (one feline indirect)
- schizogony and gametogony in the intestinal epithelium. Oocysts passed in faeces and ingested by specific species
Diagnosis of cystisospora
Faecal float -> unsporulated oocysts
- schizonts / merozoites in faces
Treament of Cystisospora
- supportive care
- sulphonamides for 1-2 weeks
- Toltrazuril for 1-3 days
Prevention and control of Cystisospora
- treat all animals
- prevent predation
- beware around whelping/lactation
Pathogenesis of Cystisospora
- mostly only mild pathogenesis but can cause diarrhoea
- young animals susceptible but can develop strong immunity afterwards.
Controlling cystisospora in piglets
Hygiene, biosecurity
medicate the sow with feed with coccidiostats
Piglet:
- single oral dose of toltazuril at 3-5 days
- Long acting sulphonamide injection at 6 days of age
Significance of Crytosporidium
- diarrhoeal disease
- faecal-oral transmission
- waterborne epidemics
zoonosis vs host specificity
Forms of Cryprosporidiosis
Intestinal: diahrrhoea, steatorrhea (fatty faeces)
Gastric: Postpandrial regurgitation
Respiratory: mostly birds
Most important cattle Cryptosporidia
C. parvum, C. bovis, C. andersoni
Major Cryptosporidia of birds
C. meleagridis
C galli
C. baileyi
Cryptosporidium lifecycle
Direct - faecal oral
- sporogony occurs within the host
- thick walled oocyst passed in the faeces (resistant to heat/chlorination)
- thin walled oocysts = autoinfection
Position of merozoite
Epicellular - intracellular but extracytoplasmic
Pathogenesis of Cryptosporidium
Villous atrophy
Epithelial mucosa release cytokines -> increase H20 and Cl-
- get watery diarrhoea (foul smelling) and malabsorption
- young animals susceptible
- older animals become more resistant
- immunocompromised animals can have a chronic disease whichmay be fatal
Features of Cryptosporidia
- Neonatal/post weaning diarrhoea (livestock, foals, pigs, pups, kittens)
- poor colostrum intake
- immunocompromised
- major waterborne pathogen
- self limiting diarrhoea
Zoonotic Cryptosporidium
C. parvum
How zoonosis occurs with C. parvum
- Only in calves less that 4 weeks old
- high intensity of oocyst excretion
- low infective dose
Diagnosis of Cryptosporidium
- Zinc or sucrose floats
- small oocytes, immunofluorescence
- smea with Ziehl-Neelsen
- ELISA or immunochromatography
- PCR
Treatment of Cryptosporidium
Supportive care - fluids/electrolytes
Hyper-immune bovine colostrum
- Halofuginone?
- Nitazoxanide?
Control of Cryptosporidium?
Hygiene (heat 70 degrees - steam, flame gun, ammonia)
- biosecurity/quarantine
- identify and isolate infected animals
- disinfect contaminated surfaces
- boil water prior to consumption (humans)
