Poultry Top Topics - Top 20 Poultry Diseases Part 2 Flashcards
what is the classic case presentation of gumboro (infectious bursal disease) in young chicks under 3 weeks old? what about older chicks?
less than 3 weeks - usually subclinical but causes chronic immune suppression
older - watery diarrhea, dehydration, & prostration
what is the etiology of gumboro?
birnavirus
how is gumboro diagnosed?
reverse transcriptase PCR on bursal tissue is most common, virus isolation, & serological tests
what is seen on necropsy of birds with infectious bursal disease?
swollen cloacal bursa of fabricius, usually yellowish but can be hemorrhagic (subclinical & recovered chickens have cloacal bursa atrophy)
how is gumboro treated?
no treatment - depopulate & disinfect
how is gumboro in chickens prevented?
vaccinate flocks to provide maternal antibodies & antibiotics provided to prevent secondary infections
what is the bursa of fabricius?
lymphoid structure in birds that is an out-pouching of the cloaca
T/F: gumboro, caused by birnavirus, has a worldwide distribution, is highly contagious, & is a reportable disease
true
T/F: pullorum disease has a high mortality rate
true
what is the classic case presentation of pullorum disease?
acute onset depression/death usually in chicks
death in adults with no preceding clinical signs
white diarrhea/pasting of the vent - may disseminate to other organs & cause grayish nodules
what other birds can be affected by pullorum disease?
turkey poults
what is the etiology of pullorum disease?
salmonella pullorum
what necropsy lesions may be seen on a bird with pullorum disease?
gray nodules on the liver, spleen, lungs, intestines, gizzard, & heart
cecal cores - caseous material in the cecum
how is pullorum disease diagnosed?
serology in adult birds
isolate & serotype from feces/fecal swabs or necropsy specimens
what is the treatment for pullorum disease?
none - cull & disinfect
could use sulfas/fluoroquinolones in valuable birds
how is pullorum disease prevented?
periodic serologic testing
how is pullorum disease transmitted?
vertical or horizontal transmission - carried by some wild birds
T/F: pullorum disease is rare in commercial poultry operations
true
what animals are affected by infectious coryza?
only chickens - usually pullets & layers
what is the classic case presentation of infectious coryza?
acute onset severe rhinitis/sinusitis, swollen heads, congested combs, conjunctivitis, nasal mucopurulent discharge, sneezing, open mouth breathing, rales, & chicken losses/drop in egg production
what is the etiology of infectious coryza?
gram-negative non-motile catalase-negative avibacterium paragallinarum
how is infectious coryza diagnosed?
culture from swabs of nasal, choanal, or sinus exudate - requires a nurse colony of staph aureus
PCR is superior to culture & can differentiate serotypes
what is the benefit of having a negative coagulase test on a bird you think has infectious coryza?
negative catalase test distinguishes it from non-pathogenic organisms which are catalase positive
how is infectious coryza treated?
susceptible to most abx - sulfas, quinolones, tetracyclines, & macrolides
vaccines for high risk areas
all-in & all-out implemented in commercial operations
what may be seen on necropsy of a bird with infectious coryza?
tenacious, yellow-gray exudate in the infraorbital sinuses
where are most cases of infectious coryza seen?
california, southeast US, & sometimes northeast US
what is the prognosis for backyard chickens with infectious coryza?
good for them - difficult to fully eradicate from large commercial operations
what animals serve as reservoirs for infectious coryza?
chronically infected chickens - horizontal transmission
T/F: infectious coryza is a highly contagious disease
true
what is the classic case presentation of fowl cholera?
fatal septicemia, peracute death, depressed/ruffled birds, anorexia, oral mucoid discharge, diarrhea, respiratory signs
pneumonia in turkeys
what clinical signs are seen in chronic cases of fowl cholera?
localized infections throughout the body
what is the etiology of fowl cholera?
pasteurella multocida
what is seen on necropsy of acute cases of fowl cholera? what about chronic cases?
acute - congestion of liver, spleen, & duodenum, & widespread hemorrhage
chronic - caseous arthritis, widespread suppurative lesions, & necrotic lung lesions
how is fowl cholera diagnosed?
bacterial isolation from clinical specimens or necropsy samples (harder to isolate from suppurative lesions from acute lesions) - blood agar & test for abx sensitivity/resistance
blood smears or impression smears for bacteremia
how is fowl cholera treated?
abx - TMS, amoxicillin, quinolones, & tetracyclines
supportive care
how is fowl cholera prevented?
commonly prevented with vaccines - bacterins & live
what birds are especially susceptible to fowl cholera?
waterfowl
what is the major reservoir of fowl cholera?
chronically infected birds
T/F: fowl cholera is highly contagious
true
what is the classic case presentation of coccidiosis?
chicks - diarrhea, sometimes bloody, dehydration, & may be fatal
depressed/ruffled, anorexia, soiled vents
mild cases can slow weight gain & decrease egg production
what is the etiology of coccidiosis?
various eimeria species - vary in host, pathogenicity, & target different segments of the intestinal tract
how is coccidiosis diagnosed?
fecal float
how is coccidiosis diagnosed in necropsy?
scrapings of intestinal mucosa - may also see distributive lesions of the gi tract
what are the 4 eimeria species & the different parts of the intestines they target?
- e. tenella - cecum, highly pathogenic
- e. nectrix - mid-small intestines, highly pathogenic
- e. acervulina - upper small intestine, moderately pathogenic
- e. mitis - lower small intestine, little pathology
what is the prognosis of coccidiosis in chickens?
prognosis depends on the species of eimeria involved
