Lecture 28 - Avian Influenza and Infectious Bursal Disease

Influenza

Avian what condition is also known as fowl plague, is found worldwide, infects all avians, but mainly turkeys, and is caused by the orthomyxovirus type A influenza virus? The type is classified based on pathogenicity.

A

The type what influenza virus is an orthomyxovirus, and is the causative agent of avian influenza?

HPAI

Which strain of avian influenza (abbreviated) is more pathogenic, and has subtypes classified according to surface proteins, like hemagglutinin and neuraminidase? In wild birds and domestic ducks signs are rare, but in chickens and turkeys signs vary from sudden death to less fulminating disorders. Mortality and morbidity are 50-90%.

LPAI

Which strain of avian influenza (abbreviated) is less pathogenic? In wild birds there will be no signs, and in domestic poultry there will be respiratory signs, decreased consumption, lower egg production, diarrhea, and high morbidity with low mortality.

H5, H7

All highly pathogenic strains of avian influenza have been either of which two subtypes? The majority involve H5N1, which is zoonotic.

Yes

Can avian influenza be spread by excretions, fomites, and direct contact, as well as using wild and domestic waterfowls as main reservoirs?

3-7

At how many days post infection with HPAI influenza viruses will chickens and turkeys show nervous disorders, and other non-specific signs? Torticollis, opisthotonous, and inability to stand can be seen.

HPAI

Which type of influenza viruses will show edema, necrosis, and hemorrhage in skin and visceral organs? Government eradication procedures may include quarantine, slaughter, disposal, and cleanup.

LPAI

Which type of influenza viruses will have respiratory tract lesions, catarrhal/fibrinous fibrinopurulent exudate in the sinuses and trachea, hemorrhage in the oviduct/ovaries, and catarrhal-fibrinous exudate in the peritoneal cavity?

Yes

Can isolation, serology, PCR, and dead or live specimens be used to diagnose avian influenza?

Yes

May swine be a possible source of avian influenza virus?

Subtype

Vaccines are available against avian influenza but they are specific to the virus what? These can be used once this is identified.

No

Do birds vaccinated with vectored vaccines and DNA vaccines react to double diffusion tests?

Infectious Bursal Disease

What condition is abbreviated IBD, was first reported in Delaware, is found worldwide, is a major problem in broilers, and is a member of the Birnaviridae family? It infects chickens only and is shed in feces and contaminated water/feed.

3-7

Most clinical signs from IBD occur between what weeks after infection? Sudden onset of disease has high morbidity and low mortality (20-30%), and during the peak infection there will be anorexia, depression, profuse watery diarrhea, ruffled feathers, and vent pecking. Severe prostration will precede death.

2-3

By what day of IBD infection will the bursa increase in size and weight, and produce a gelatinous yellow exudate with hemorrhage?

4

By what day of IBD infection will the bursa double in size?

5

By what day of IBD infection will atrophy start?

8

By what day of IBD infection will the bursa come to normal or smaller size and produce evidence of necrosis and caseous exudate? Nephrosis, and extensive hemorrhages in the thigh and breast muscles and proventriculus will later be seen.

Yes

Can clinical signs, lesions, isolation, serology, and PCR be used to diagnose IBD?

Chicken

What animal is the only one affected by infectious bursal disease?

Yes

Are vaccines and antibiotics commonly used to treat/prevent IBD? This is done in water at 2-3 weeks in chicks and a booster is given at 16-18 weeks by injection.