Unit 1 - Avian Part 3 (Enteric) Flashcards
What is the etiologic agent for coccidiosis?
Eimeria
True or False: Eimeria is not host specific?
False - Eimeria is very host specific
How is coccidiosis transmitted?
Fecal oral transmission
When are birds often infected by coccidiosis?
After 3 weeks of age
How long does it take for Eimeria oocysts to sporulate and become infective?
1-3 days
Commercial poultry may go through __ rounds of infection before becoming immune.
3
True or False: Bloody diarrhea is always observed with coccidia infections.
False - some coccidia do not invade the intestinal mucosa as deeply and bloody diarrhea is not always observed
What clinical signs are associated with coccidia infections that do not invade the intestinal mucosa?
Weakness, depression, and necrotic enteritis
What clinical signs are associated with coccidia that invade more deeply into the intestinal mucosa?
More severe disease, bloody diarrhea, and necrotic enteritis
In the absence of preventative measures what population of birds can have 50% mortality due to coccidiosis?
Farmyard pheasants, quail, and partridges
How is coccidiosis prevented?
sanitation and immunization
What type of bedding is bad for coccidiosis overgrowth?
Wet litter and mud
What in bedding will kill coccidia oocysts
Ammonia
What types of vaccines are available for coccidiosis?
Live attenuated vaccines for some species
Non-attenuated vaccines with low doses of sporulated oocysys
What is the benefit of a low dose vaccine against coccidiosis?
Low doses allow time to develop an immune response
Why are coccidiostats problematic?
Drug resistance is a big problem
Most coccidiostats allow for come _____ of coccidia and allow for development of immunity.
replication
What are coccidiostats often used in combination with?
Vaccines
Explain the protocol for using coccidiostats with vaccines.
Clean up a facility first to get rid of resistant coccidia
Inoculate new birds with coccidia that are still susceptible to coccidiostats
Treat with coccidiostats as needed to control clinical signs
What is used to treat coccidiosis?
Amprolium, Avatex, tetracyclings, and sulfa drugs
What drug is not recommended for treatment of coccidiosis because of the very long withdrawal time?
Ponazuril
What is infectious bursal disease (IBD) also known as?
Gumboro disease
What is the etiologic agent of IBD?
Avibirnavirus in the Birnaviridae family
There are two serotypes of IBD, which one causes disease?
Serotype 1
What is the mortality rate for classical strains of IBD?
20-50%
How do variant strains of IBD present?
No clinical signs or mortality - just lymphocyte depletion without inflammation of bursa
What is the mortality rate for vvIBD?
50-100%
True or False: Disinfectants are key to IBD control
False - they are very resistant to infections
What age group has the highest mortality due to IBD?
Between 3-6 weeks of age
When are chickens no longer susceptible to IBD?
The bursa stops functionig by 16 weeks and they are no longer susceptible
What is the main problem associated with IBD?
immunosupperssion
What does the IBD virus attack?
IgM and B-cells in the bursa
At what age can infection with IBD result in permanent immunosuppression?
If infected <3 weeks of age
At what age can infection with IBD result in reversible immunosuppresion?
6 weeks of age
What clinical signs are associated with IBD?
Feathers around the vent are stained with feces containing lots of urates
Depression, diarrhea, anorexia, incoordination
depression
Ruffled feathers especially in the head and neck area
What lesions are associated with IBD?
Initial enlargement of the Bursa of Fabricius and subsequent atrophy
Hemorrhages in the bursa, muscles of the legs, and breast
Severe urate deposition in the kidneys
How is IBD diagnosed?
Histopathology, virus isolation, serology, ELISA, and virus neutralization
How is IBD prevented and controlled?
Thorough cleaning and disinfection of facilities
Killed vaccine for breeders
MLV vaccine for chicks
Recombinant HVT
What is the etiologic agent of necrotic enteritis?
Clostridium perfringens mostly type A and some C
True or False: Chickens with multiple strains of Clostridium perfringens usually do not have disease
True
Diseased chickens with necrotic enteritis usually have a single pathogenic strain or clone. What do these strains produce?
Bacteriocin that kills off other C. perfringens
Ned B
Collagenase
What are the predisposing factors for necrotic enteritis?
High energy, high protein feeds, high levels of small grains
Subclinical coccidiosis or salmonellosis
What population of chickens are mostly affected by necrotic enteritis?
Mostly broilers and some layers
What clinical signs are associated with necrotic enteritis?
Dark, blood-stained feces, dehydration, sudden deaths, ataxia, somnolence, depression, and poor weight gain with ‘subclinical’ cases
What part of the intestine does necrotic enteritis affect?
Mid to distal small intestine
If necrotic enteritis is treated, the mortality can be around ____%. If untreated, mortality can be ____%.
2%, 50%
How is necrotic enteritis diagnoised?
With gross lesions and demonstration of organisms on mucosa
How is necrotic enteritis prevented?
Controlling coccidia
How is necrotic enteritis treated?
Penicillins or other antibiotics in drinking water
What species does gangrenous dermatitis affect?
Turkeys and chickens
What causes gangrenous dermatitis?
Clostridium septicum, C. perfringens Type A, and staphylococcus aureus singly or in combination
Gangrenous dermaititis has _____ onset, and (acute/chronic) mortality.
Rapid, acute
What is gangrenous dermatitis?
Necrosis of the skin and subcutaneous tissues
What is gangrenous dermatitis often associated with?
Immunosuppression such as with infectious bursal disease or other infections
What can help eliminate gangrenous dermatitis from a facitlity?
Thorough cleaning and disinfection
What is salmonellosis also known as?
Pullorum disease
What is the etiologic agent of pullorum disease?
Salmonella enterica subspecies enterica serovar Gallinarum biovar Pullorum
What population of birds is Salmonellosis of concern for?
Home-raised chicks, gamebirds, etc.
How is Pullorum disease transmitted?
Bird to Bird transmission, contact, cannibalism, wound contamination, and fecal contamination
Can eggs become infected with Salmonella?
Yes, about 1/3 of eggs will be infected, but chicks hatch with the infection
How does pullorum disease spread?
Laterally
What clinical signs are associated with Pullorum disease?
Weakness, anorexia, chalky white feces, and death by 2-3 weeks
How is Pullorum disease prevented?
Purchase only pullorum-free birds and good biosecurity
How is Pullorum disease treated?
It is unwise to treat it -just euthanize and sanitize
What is the etiiologic agent of Fowl Typhoid?
S. enterica subspecies enterica serovar Gallinarum biovar gallinarum
How is fowl typhoid transmitted?
Horizontal and vertical transmission
What does fowl typhoid resemble in young birds?
Pullorum disease
What group of birds is fowl typhoid a serious problem in?
Growing and adult chickens and turkeys
Fowl typhoid has been eradicated from developed countries, but has been re-introduced on occasion to what farms?
Commercial poultry farms
What can happen to birds hatched from fowl typhoid infected eggs shortly after hatching?
they can die