L16-18

Question 1

Cause of Reoviral arthritis or tenosynovitis

Answer 1

Reovirus with joint tropism

Question 2

Reoviral arthritis or tenosynovitis affects what species?

Answer 2

Mainly meat-type chickens between 4-16 wks

Question 3

Trans. Of Reoviral arthritis or tenosynovitis

Answer 3

vertical (Egg transmission**) and horizontal

Shed in feces
Fomites
Infected chickens remain carriers for months

Question 4

Pathogenesis of viral arthritis

Answer 4

• virulent strains cause arthritis and sometimes death
• virus replicates in intestines
• some invade joints –> arthritis

Question 5

CS of viral arthritis

Answer 5

• lameness
• joint swelling
• wt. loss, stunting, death

Question 6

Gross lesions of viral arthritis

Answer 6

• tendon sheaths swollen and dull
• hemorrhages in and around joints*
• exudate in tendon sheaths

Question 7

Dx of viral arthritis

Answer 7

• smears of synovial fluid (inflammatory)
• virus isolation in eggs
• BEST = PCR of RNA from lesions**
• histopath
• serology: ELISA

Question 8

Changes to egg infected with reovirus

Answer 8

• Induces plaque formation on chorioallantoic membrane

- embryo becomes hemorrhagic

Question 9

Ddx for viral arthritis

Answer 9

Mycoplasmoses
Staphylococcal arthritis
Colibacillosis
Salmonellosis
Nutritional imbalances
Pasteurellosis
Marek's disease

Question 10

Vax for viral arthritis

Answer 10

Live attenuated in pullets
Inactivated in layers

Maternal Ab prevent early infection in chicks and minimize egg transmission

Question 11

Cause of avian pox

Answer 11

Poxviridae (DNA virus)

-a hardy virus

Question 12

Trans. Of avian pox

Answer 12

-mosquitoes and other biting insects = mechanical vectors

Question 13

Forms of fowl pox

Answer 13

1) cutaneous (lesions on skin)
2) diphtheritic (plaques or lesions in oral or upper RT mucosae) “wet pox”

-virulent forms can cause lesions in internal organs too

Question 14

In canaries, avian pox is associated with:**

Answer 14

Systemic infections and high mortality

Question 15

Key characteristic microscopic lesion of avian pox virus***

Answer 15

Produces intracytoplasmic inclusions in infected epithelial cells***

Question 16

Dx of avian pox

Answer 16

• Gross lesions
• Microscopic lesions (intracytoplasmic inclusions, hyperplastic epithelium
• Virus isolation from embryos
• PCR of DNA extracted from lesions**
• electron microscopy

Question 17

Control of avian pox

Answer 17

• control biting insects
• vaccinate and examine for “takes” 1 wk later**

If no “takes” are observed, birds have maternal Ab, or vaccine didn’t work

Question 18

Is avian pox zoonotic?

Answer 18

No

Question 19

Antibiotic sensitivity assays are usually used for what purpose

Answer 19

To confirm that the chosen and already used abx was the correct on during an outbreak

Question 20

How long does it take for a petri dish to have confluent growth of isolated bacteria for abx sensitivity assay?

Answer 20

24-48 hr