Gumboro Disease Outbreak in a Vaccinated Pre-lay Poultry

Gumboro Disease Outbreak in a Vaccinated Pre-lay Poultry
 

Introduction

Infectious bursal disease is an acute contagious viral disease of young chickens caused by an RNA-virus which is classified as a member of the genus avibirnavirus of the Family Birnaviridae (Dobos et al., 1979; Brown, 1986).

Turkeys, ducks, guinea fowls, and ostriches may occasionally be affected by the disease (Johnson et al., 1980; McFerran et al., 1980).

The disease was first reported in USA in 1962 by Cosgrove and was referred to as “avian nephrosis” because of the extensive kidney damage in birds that succumbed to the infection (Cosgrove, 1962); and subsequently in other countries including Nigeria (Ojo et al., 1973; Onunkwo, 1975).

Although, IBD is primarily a disease of young (between 3 and 6 weeks) and unimmunized chickens, reports of the disease in vaccinated chicken flocks aged 16-20 weeks have been reported (Okoye and Uzoukwu, 1981; Durojaye et al., 1984; Awolaja and Adene,1995). The aim of this study was to document a case of Gumboro disease in a 13th week old vaccinated flock.

Materials and Methods

A. Flock and Clinical Data:

The farm was visited to collect flock data and clinical history. Recorded farm data were supplemented with information given by farmer in response to questions on course of disease, previous and recent medication.

B. Pathology:

After the gross pathological examination and diagnosis of the case as IBD, tissue specimens of grossly affected organs (i.e bursae and spleen) were collected and fixed in 10% buffered formalin; paraffin embedded tissues, were sectioned at 5 microns, stained with haematoxylin and eosin (H & E), mounted on glass slides and examined under light microscope at X400.

C. Bacteriology:

Samples of aseptically collected liver, lung and spleen were inoculated into nutrient broth, as well blood agar and MacConkey agar. Cultures were incubated in an incubator at 37oC and examined daily for microbial growth.

D. Antigen Detection:

Homogenized extracts of bursae Fabricius, heart, lung and spleen were reacted against known positive IBD sera in agar gel precipitation test (AGPT), for presence of IBD antigen in the tissue extracts.

E. Parasitology:

Cecal and intestinal samples were processed and examined for helminth ova and Eimeria oocysts.

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