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
What is the site of infection for E. tenella?
Develops in cells of ceca
Describe the Pathogenesis of E. tenella
Acute infection most commonly in young chicks
Characterized by presence of blood in droppings
High morbidity and mortality
First noticeable about 3 days after infection
- Chickens droop, stop feeding, huddle together
Day 4
- Blood in droppings
- Increases until day 9
Death occurs unexpectedly
- Due to excessive blood loss
Birds who recover may develop chronic illness as a result of persistent cecal core (of clotted blood)
- Core usually detaches in 8-10 days, shed in droppings
Sloughing of epithelium
Plugged cecum due to clotted blood and cell debris, causing necrosis
Explain the life cycle of E. tenella
Infection
Merogony I, II, III(IV)
Gametogony
Sporogony
How do you treat E. tenella?
Prophylaxis using coccidiostats in food and water
Vaccines, effective with species specificity
Annual expenditures for coccidiostats worldwide are estimated to be $250-300 million
Describe the site of infection of E. necatrix
Small intestines (early stages)
Cecum (sexual stages)
Describe the Pathogenesis of E. necatrix
Bloody droppings
Dehydration
Cecal coccidiosis
What is the site of infection of E. acervulina/E. maxima?
Upper part of small intestine
Describe the Pathogenesis of E. acervulina/E. maxima
Subclinical coccidiosis
Marked weight loss
Describe Eimeria in turkeys
Infections most as pathogenic
E. adenoides, E. meleagrimitis, E. galloparvonis, E. dispersa
Oocyst range: 16x19 micro m to 21x26 micro m
All ages are susceptible to primary infections
Birds older than 6-8 weeks more resistant
What are the hosts?
Sheep
Goats
Birds
Cattle
How do you identify in cattle?
Unsporulated oocyst in feces
Sporulate for identification
Explain the life cycle in cattle
Sporulated oocyst ingested
Excystation of oocyst
Merogony
Gametogony
Fertilization
Excretion
Unsporulated oocyst
E. bovis
- PPP: 15-20 days
- 1st generation schizont: endothelial cells of lacteals of small
intestine
- 2nd generation schizont: epithelial cells of large intestine
- Gametogony: epithelial cells of large intestine
E. zuernii
- PPP: 15-20 days
- 1st generation schizont: Lamina propria cells
- 2nd generation schizont: Epithelial cells of small (very few) and
large intestine
- Gametogony: epithelial cells of small and large intestines
What are the sites of infection in cattle?
Small and large intestines
Lesions in large intestines
Describe the Pathogenesis in cattle
Inflammatory changes in mucosa
Disruption of mucosa of large intestines
Describe the clinical signs in cattle
Diarrhea (mild to severe)
- Profuse - Watery - Bloody - Projectile
Severity related to parasite density and number of cells affected
How do you diagnose in cattle?
Fecal flotation to detect Oocysts
How do you treat and prevent in cattle?
Coccidiasis is inevitable - immunity
Coccidiosis is preventable
- Coccidiostats - Hygiene
