Eimeria spp. (1) Flashcards
How do you identify in sheep and goats?
Sheep
- E. crandallis - E. ovinoidalis
Goats
- E. ninakohlyakimovae - E. caprina - E. arloingi - E. christenseni - E. hirci
Explain the life cycle in sheep and goats
Sporulated oocyst ingested
Excystation of oocyst
Merogony
Gametogony
Fertilization
Excretion
Unsporulated oocyst
What is the site of infection?
Small and large intestines
Describe the Pathogenesis
Inflammatory changes
Disruption of mucosa
Outbreaks associated with:
- Lambs 1-3 months old
- Lot-fed animals
- Irrigated pastures
- Corralling
- Stress
- Transportation
- Temperature changes
What are the clinical signs in sheep and goats?
Diarrhea - putty-like to watery to bloody (E. ovinoidalis)
Leads to dehydration and weakness
Severity related to species, parasite density and number of cells affected
How do you diagnose in sheep and goats?
History
Clinical signs
Fecal flotation to detect Oocysts
Sporulation for species
How do you treat and prevent in sheep and goats?
Coccidiasis is inevitable
Coccidiosis is preventable
Risk factors
- Overcrowding (Feedlot situations)
- Unhygienic conditions (Feed contaminated by feces)
- Mixing of different age groups
- Stress
- Inclement weather
- Transport
Prevented by improving management of animals
- Preventing overcrowding - Improving hygiene
Control of Coccidiosis
- Animals sufficiently exposed to develop immunity without
developing overt clinical disease
- Coccidiostats used prophylactically to achieve this purpose
Treatment of isolated cases
- Require both anticoccidial medication and supportive therapy to
rehydrate
- Prevent secondary bacterial infection
In birds which is more common?
Coccidiasis is more common than coccidiosis
How do you identify in birds?
Description of Oocysts are insufficient for species diagnosis
Explain the life cycle in birds
Sporulated oocyst ingested
Excystation of oocyst
Merogony
Gametogony
Fertilization
Excretion
Unsporulated oocyst
What are the sites of infection in birds?
Small and large intestines
Describe the Pathogenesis in birds
Bloody droppings
Dehydration
E. tenella most pathogenic species in young chicks
High death rate
Recovered birds may be chronically ill due to persistent core of clotted blood in cecum
How do you diagnose in birds?
Oocysts can be seen in feces
- Speciation difficult even with sporulation - Relatively site specific (different areas of small/large intestines)
Best accomplished by necropsy examination of representative number of birds
- Location of major lesions gives indication of species
E. tenella in ceca
E. necatrix in small intestine
E. brunette in ileum, cecum, and rectum
How do you treat and prevent in birds?
Poultry industry loses more than $700 million annually
Challenges:
- Confined-host rearing conditions
- High levels of infection
- Development of drug-resistant Coccidia strains
Few management practice include:
- Anticoccidial drugs mixed in feed - limit high levels of infection
- Keep chicks, feed, water away from droppings
- Roost birds over wire netting
- Place water vessels on wire frames to eliminate concentration of
wet droppings
- Keep litter dry and stir frequently
- Remove wet spots, replace with dry litter
- Avoid overcrowding
- If coccidiosis does break out, start treatment immediately
Several coccidiostats available
- Withdrawal periods and contraindications should be strictly
followed
Emergence of drug resistant strains
- Methods used to avoid development of drug resistant strains:
- Switching classes of drugs
- "Shuttle program"
- Planned switch of drug in middle of bird's growth period
Control
- Use of vaccines
- Used mostly for egg laying birds
- Chicks treated soon after hatching
- Lifelong immunity
Describe in chickens
Only some species cause severe clinical disease
Oocysts range: 12x30 to 13x40 micro m
E. tenella, E. brunetti, E. necatrix - most pathogenic
