Poultry viral disease caused by Reovirus

2. Avian Reovirus
Dr. NaeemTahir
Assistant Manager Sales
Jadeed Farms (Pvt) ltd.
Faisalabad

3. Introduction
 In 1957, Olson and his coworkers determined that the
synovitis agent was a virus, which they called “viral
arthritis agent.”
 The virus was subsequently identified by Walker as a
reovirus by electron microscopy.
 Soon other isolations of reovirus were reported from
various places in the United States and all around the
world.

4.  Cases of Reovirus tenosynovitis have been
reported throughout the UK in a number of
integrations this year.
 Cases of Reovirus tenosynovitis have been
reported throughout Europe and
United States of America and
many other Asian and African
countries throughout the last year.
Occurrence

5. Virus isolation
 Aseptically extracted tendon tissue from
broilers
 Virus isolation conducted by AHVLA
Weybridge
 3 Passages Reovirus isolated FROM
TENODONTISSUE

6. Histology
 Tendons, joint capsule and tendon sheath-
mixed inflammatory infiltrate- both
heterophilic and lymphoplasmacytic.
 NOT POSSIBLE TO DETERMINE WHETHER
BACTERIAL OR VIRAL FROM HISTOLOGY
ALONE.

7. General Characteristics
 Birds reported lame “walking
on their hocks using wings to
balance”.
 Acute onset at 13-14 days of
age.
 Poor uniformity
 Poor growth rates

8.  Bursa of Fabricius and thymus gland are
atrophied.
 Femoral head disintegration on
disarticulation of the coxofemoral joint.
 Thickening of the growth plates of long
bones.
 Arthritis and osteoporosis.

9. Transmission
 Through infected and carrier birds
 Poultry products, offal's from infected birds
 Mechanical vectors
 Wild birds
 Faulty vaccination
 Contaminated feed and water
 Vertical route of transmission is also proved

10.  Thymus cortex is thinner and difficult to be
differentiated from medulla.
 Atrophy of follicles of Bursa of Fabricius.
 Bones abnormality in the femur growth plate with
necrosis of cartilage.
 Proventriculitis with focal necrosis and infiltration of
Inter glandular tissue with mononuclear cells.
Histopathological lesions

11.  Distended abdomen
 Increased fluid in tendons of hocks
 Concurrent mild pericarditis/epicarditis
 Enlarged proventriculus
 Shrinkin pancreas
 Intestine containing undigested orange
feed
Postmortem examination

12. Differential diagnosis

13. Primarily considered likely infectious
agent given inflammation and effusion
of tendon
Mycoplasma Synoviae
StaphylococcusTenosynovitis/ Arthritis
EnterococcusTenosynovitis/Arthritis

14. Airsacculitis Inflammation
of joints
Ruffle feather Distended
abdomen
Shrinkin
pancreas
Reovirus Nil Yes Yes yes Yes
Mycoplasma
Synoviae
Yes In some cases Yes Nil Nil
Staphylococcus
Tenosynovitis/
Arthritis
Nil Yes Yes Nil Nil
Enterococcus
Tenosynovitis/A
rthritis
Nil Yes Yes Nil Nil

15. 1- Staphylococcus Tenosynovitis /
Arthritis Swabs taken from hocks,
tendons and pericardial tissues
Results – no growth after 48 hours
Birds swabbed not being treated with
antibiotics and investigation undertaken at
early stage of infection
NOT STAPHYLOCOCCUS OR
ENTEROCOCCUS
TENOSYNOVITIS/ARTHRITIS
Course of investigation

16. 2- Mycoplasma Synoviae
Serology:
Rapid serum agglutination on sera of 20
birds showing symptoms in affected
flock- taken at time of site visit
Results- negative
However- serology relies on antibody
production- acute vs convalescent
phase of infection- could not rule out on
the basis of this test alone

17. Then……..
8-12% mortality due to culling
No response to antibiotic treatment either antimycoplasmal or
amoxycillin
Welfare concerns due to lameness
Poor conversion 1.80+ vs 1.62
Poor uniformity
Some response to aspirin treatment-
– better mobility, lower culling rates

18. Questions!
 Why have so many companies and countries
suddenly reported this syndrome?
 Why have some flocks which have not been derived
from the known positive PS also developed symptoms?-
cross infection in hatchery?
 Why did some flocks from the same parent flock not
show symptoms?- age related resistance?

19.  Is this a new strain of Reovirus or is it a previously
recognised strain?- Reoviruses appear to be continuously
involving.
 What methods are being used to type Reovirus and
are these consistent throughout laboratories?- there is no
consistency at this time.
 Will double Reo inactive vaccination confirms
protection?

20. • Biosecurity
• Hatching egg hygiene
• Hatchery hygiene
• Vaccination- double vaccination strategy
advised in outbreak areas
• Sigma B antibodies
• Autogenous vaccination
Prevention and Control

21. General appearance of the effected bird

22. Swelling of hock joint

23. Diagrams of Post mortem Lesions
of Avian Reovirus

24. Enlarged Proventiculus

25. Distended abdomen

26. Tissue fibrosis in the affected area

27. Tendon sheaths contain a small amount of
straw-yellow exudates

28. Intestine containing
undigested orange
feed
Catarrhal enteritis with white
color and Dilated intestine.

29. Shrinkin pancreas in affected broiler

30. Shrinkin pancreas in affected broiler

31. Small intestine is pale, dilated and
contain indigested forage

32. Small intestine is pale and dilated

33. Thank you