Poultry Top Topics - Top 20 Poultry Diseases Part 1 Flashcards
what is the other name for newcastle disease?
avian pneumoencephalitis
what is the classic case presentation of newcastle disease?
acute onset of severe respiratory and/or neurologic and/or gi signs
what respiratory signs are seen in newcastle disease?
gasping, sneezing, coughing, facial edema causing square head, & reddened lower eyelid over the lymphoid patch
what neuro signs are seen in newcastle disease?
paralysis, tremors, droopy wings, torticollis, circling, but bright & alert despite severe neuro deficits
what gi signs are seen in newcastle disease?
watery green diarrhea
what other clinical signs apart from respiratory, neuro, & gi may be seen in chickens with newcastle disease?
sometimes sudden death
decreased egg production with thin shells & watery albumin
what is the etiology of newcastle disease?
RNA avian paramyxovirus-1
what is the gold standard test for dead & alive birds with newcastle disease?
dead birds - virus isolation on lung, kidneys, or gi tract
live birds - virus isolation from nasopharyngeal & tracheal exudate swabs
what lesions seen on necropsy are almost pathognomonic for newcastle disease?
multifocal necrosis, hemorrhagic intestinal mucosa especially at lymphoid foci (cecal tonsils)
how is ICPI used in chickens?
for newcastle disease - day old chicks are inoculated to determine virulence of newcastle
how will a newcastle disease positive chicken test on hemagglutination?
positive
how is RT-PCR used on newcastle chickens?
done for pathotyping & genotyping
how is newcastle disease treated?
no treatment - have to cull all birds on the premises
how is newcastle disease prevented?
good management practices as the disease spreads quickly through facilities through aerosol exposure
indoor operations are better - outdoor flocks are at a higher risk
vaccines in countries where virulent virus disease outbreaks occur
T/F: outdoor flocks are at a larger risk of getting newcastle than indoor flocks
true
how are the different types of avian paramyxovirus labeled based on ICPI?
how fast they kill embryos post-inoculation
lentogenic - slow, used in vaccines & not reportable
mesogenic - medium
velogenic - fast & divided into 2 categories: viscerotropic (gi) velogenic newcastle disease & neurotropic (brain) velogenic newcastle disease
how do different strains of APV1/PMV-1 vary?
differences in surface glycoproteins, hemagglutinin-neurominidase (HN), & fusion (F)
what strains of newcastle disease are reportable in the united states?
mesogenic & velogenic strains
what is the zoonotic risk of newcastle disease?
causes transitory conjunctivitis in humans
what is the classic case presentation of marek’s disease?
clinical signs based on which organs/tissues t-lymphocytes infiltrate
sciatic nerve paralysis - one foot forward & one back
gray eye - lymphocytic infiltration of iris
affects young chickens 2-5 months old - decreased growth rate, egg production, & enlarged feather follicles which are a cause of condemnation
what is the etiology of marek’s disease?
oncogenic lymphotrophic alphaherpesvirus genus mardivirus
how is marek’s disease diagnosed?
virus isolation, PCR (for viral dna in lymphoid tumors), AGID
histopath & IHC
what found on necropsy helps to distinguish marek’s disease from lymphoid leukosis?
the bursa is rarely affected & is usually atrophic in marek’s
where are lymphoid tumors from marek’s disease found in the body? what else is seen at necropsy?
liver, spleen, gonads, heart, lungs, kidney, muscles, & proventriculus
enlarged peripheral nerves - especially sciatic nerve
how is marek’s disease treated?
none - supportive care in pet poultry
what prophylactic treatment is done to prevent marek’s disease?
vaccinate in ovo or day old chicks to decrease shedding
the virus that causes marek’s disease causes what in chickens?
lymphoproliferative disease/neoplasia
how is marek’s disease transmitted?
no vertical transmission!!!!
horizontal transmission mainly via inhalation of aerosolized chicken dander that can travel on wind between flocks
what serves as the main reservoir of marek’s disease?
silent recovered lifelong carriers
T/F: the virus that causes marek’s disease is practically ubiquitous, so all flocks are assumed to be infected
true
you see enlarged sciatic nerves on necropsy of a chicken, so what disease are you thinking?
marek’s disease
what clinical signs are seen with low pathogenicity avian influenza?
mild to moderate respiratory signs, poor weight gain, & egg drop
what clinical signs are seen with high pathogenicity avian influenza?
fowl plague - peracute death, prostration, cyanosis of head/appendages/petechiation in viscera, oral/nasal bloody discharge, diarrhea, neuro signs, hemorrhages of the limbs, & disease that spreads rapidly
what is the etiology of avian influenza/fowl plague?
orthomyxovirus, influenza type a
how is avian influenza typed?
virus isolation in eggs from clinical samples with RT-PCR
hemagglutination positive
hemagglutinin & neuraminidase typing & subtyping also done by inhibition tests using antisera
what subtypes of high pathogenicity avian influenza are most often implicated in disease?
H5 & H7 HPAI
how is avian influenza prevented?
autologous vaccine that requires state veterinarian approval & strict biosecurity
how is HPAI treated? how is LPAI treated?
HPAI - no treatment, depopulate
LPAI - supportive care & abx
what type of avian influenza is reportable?
HPAI - H5N1 & H7N& can be fatal to humans
how are waterfowl/seabirds implicated in spreading avian influenza?
disease often carried long distances by subclinically infected waterfowl or sea birds
what is a major concern with containment of avian influenza?
gene re-assortment occurs in developing countries or in markets where humans, fowl, & swine intermix creating new genotypes
if you have a sick chicken that presents clinically like this, what disease are you thinking about?
HPAI
T/F: HPAI is reportable & zoonotic
true
what can happen in a bird that recovers from infectious laryngotracheitis?
latent infection - can recrudesce when birds are stressed
what is the classic case presentation of a bird with infectious laryngotracheitis?
acute outbreak of gasping, coughing, conjunctivitis, dyspnea, blood stained beaks in chickens under 4 weeks old, decreased egg production
variable mortality but often high
what clinical signs are seen in cases of chronic infectious laryngotracheitis?
poor weight gain in broilers
what is the etiology of infectious laryngotracheitis?
gallid herpesvirus 1
what is seen on necropsy/histopath of birds with infectious laryngotracheitis?
necropsy - blood, mucus, caseous exudate, or hollow cast in trachea
histopath - inclusion bodies
how are flocks screened for infectious laryngotracheitis?
ELISA or virus neutralization serological tests
how are clinical cases of infectious laryngotracheitis diagnosed?
virus isolation or PCR
how is infectious laryngotracheitis treated?
no treatment - immediately vaccinate adults during an outbreak
how is infectious laryngotracheitis prevented?
biosecurity & vaccination
why not vaccinate chickens with attenuated vaccines for infectious laryngotracheitis?
regularly has resulted in disease through serial virus passage in vaccinates
T/F: birds that recover from infectious laryngotracheitis are lifelong carriers
true
how is infectious laryngotracheitis transmitted?
seen worldwide - transmitted horizontally through aerosol & fomites
T/F: infectious laryngotracheitis is a reportable disease in fowl
true
what is the classic case presentation of infectious bronchitis seen in the youngest birds?
acute onset upper respiratory signs (sneezing, conjunctivitis, swelling) & lower respiratory signs (dyspnea, rales, coughing)
what is the classic case presentation of infectious bronchitis seen in the breeders & laying birds?
sharp decrease in egg production & misshapen or wrinkled egg shells
what is the morbidity & mortality like for infectious bronchitis of birds?
variable mortality but almost 100% morbidity
what is the etiology of infectious bronchitis?
RNA coronavirus
what is seen on necropsy of birds with infectious bronchitis?
white urates in renal tubules
what hemagglutination result would a bird with infectious bronchitis have?
NEGATIVE
how is infectious bronchitis diagnosed?
virus isolation in chick embryo & paired serology
how is infectious bronchitis treated?
none - supportive care, abx for secondary infections
how is infectious bronchitis prevented?
vaccines & strict biosecurity
T/F: infectious bronchitis in birds is a common contagious disease with worldwide distribution that may be reportable in some states
true
T/F: some strains of infectious bronchitis cause reproductive issues & some are nephrogenic
true
