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Protozoa causing diarrhoea - Coggle Diagram
Protozoa causing diarrhoea
Coccidiosis - Eimeria tenella
Pathogenesis
Tissue damage
Dehydration and blood loss
Malabsorption + malassimilation
Secondary bacterial infections
Clostridium + Salmonella
Immunosuppression - complications
Marek's Disease ; Infectious Bursal Disease
Diagnosis
Life cycle
Continuous asexual reproduction
Single sexual reproduction
4 sporocysts - 8 protozoa released
PPP: 6-7 days
Faecal float: Oocysts present in faeces
Day 7 - immunity established
Anticoccidial drugs ineffective
Sexual reproduction --> release oocysts
Lesion site in PM
Necrotic enteritis
Colonisation of different GIT components
Specific strains
Clinical signs - low levels of faecal oocysts
Treatment
Anticoccidial drugs added into feed
Rotation prevents resistance
Coccidostats
Control strategy
Oocysts resistant to disinfectants
Sanitation + litter management
Reduce oocyte ingestion
Crowded conditions - intensive production
Cage layers - lower incidence
Source of infection
Ionophors, sulfa-drugs
Toxicity + withdrawal periods
Precocious vaccine lines
Younger chicks Day 1
4 weeks most susceptible
Immunity established in older birds
Giardia
Key routes of infection
Faecal-oral transmission
Feed and water contaminated with cysts
Attach to brush border of duodenum / jejunum
Microvilli atrophy
Crypt hyperplasia
Decreased absorptive surface
PPP: 5-16 days
Host specificity
Young puppies undergoing GIT flora transition
Lactobacillus only dominates becomes
Firmicutes / proteobacteria dominated
Change in diet + environment stressors
Zoonosis
G. duodenalis - Assemblage A
G. enterica - Assemblage B
Diagnosis
Clinical signs
Dogs + cats: Intermittent smelly fatty diarrhoea; vomiting; weight loss
G. canis - Assemblage C
G. cati - Assemblage F
Ruminants: Diarrhoea + weight loss
G. bovis - Assemblage E
Horse: Diarrhoea, ill-thrift, reduced growth rate
Often asymptomatic
Coproantigen tests + PCR
3 faecal samples over 10 days
Fluctuating pathogen numbers
Control / treatment
Relive clinical signs
Prolonged recovery period
Not parasite elimination
Drugs
Fenbendazole
Remove cysts from feces
Prevent infections
Multiple doses over 5 days
Proziquantel dewormer
Environmental management
Quaternary ammonium disinfectant
Minimise handling
Remove moisture
Tritrichomonas foetus
Control measures
Single cat household
Ronidazole
Neurotoxicity risk
Resolve within 2 weeks
RDZ resistance
Multi-cat household
Isolate treated cats
Higher reinfection risk
Diagnosis
Clinical signs
Waxing and waning large bowel diarrhoea
Good health, normal appetite and body condition
Culture + PCR
Coccidia - Cryptosporidium spp.
Key routes of infection
Waterborne - faecal oral route
<2 weeks old calves
Immunocompromised
Oocyst containing 4 sporozoites
Auto-infective
PPP: 3-5 days
Pathogenesis
Villous atrophy + crypt hyperplasia
Malabsorption + hypersecretion
Mixed inflammatory cell infiltrate
Enteric cryptosporidiosis
Infectious enteritis
Gastritis
Cloacitis
Host specificity
Zoonotic
Other forms
Abomasal - mildly pathogenic
Parvum
Zoonotic
Andersoni
Diagnostics
Clinical signs - often absent
Ruminants : Diarrhoea; weight loss; dehydration; anorexia
Dogs and cats: Chronic and intermittent diarrhoea (rare)
Direct fluorescent antibody test (DFA)
Detect cyst antigen
Rapid coproantigen tests, PCR
Control / treatment
Unavailable
Poor penetration
Intracellular + extracytoplasmic colonisation
Self-limiting
Immunocompetent
Continous asexual reproduction