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Gumboro Disease Outbreak in a Vaccinated Pre-lay Poultry in New Pen House

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.

Results

Case history:

The case involved a flock of 240- thirteen-week old Isa brown chickens purchased from a commercial hatchery in Jos as day old chicks. The chickens were housed on deep litter and fed from day old ad libitum. Before stocking, the newly built poultry house was washed and disinfected. No previous batches of flock were kept in the pen or any place in the premises. Prior to the outbreak of the disease, all vaccination regimens were strictly followed including that of Gumboro which was given at first and third weeks of age. Chickens were initially noticed to be apparently healthy, but at 12th week, some of them were observed to be passing bloody diarrhea which resulted in mortality of 5 chickens. The condition was diagnosed to be coccidiosis which was successfully controlled with Embazin Forte® (Amprolium and sulfaquinoxaline) within 4 days.

Three days after recovery from coccidiosis, some of the chickens were later noticed to be passing brownish feces, some whitish diarrhea and the flock was generally weak and anorexic. Death commenced within a day of first sign, mortality rose sharply to a peak and declined almost rapidly, in a course of about 6 days (Figure 1). Total mortality recorded within the six days was 115 (48.9%). On the second day of the outbreak, the farmer used her discretion to administer Conflox (enrofloxacin) in order to ameliorate the condition, but no success was recorded. Four carcasses from the farm were then presented to the Central Diagnostic Laboratory, National Veterinary Research Institute, Vom, Nigeria on 8/4/2009 for necropsy.

Pathologic findings:

Post mortem examination of the four carcasses indicated that one presented with cyanosed comb, two had their vents matted with whitish-yellow diarrhea, while three were slightly emaciated. Trachea and lungs of the four carcasses appeared normal. There was hemorrhage at the proventricular junctions in two out of four chickens (Figure 2). Congested liver was noticed in two and slightly pale liver was seen in one. Kidneys of all the 4 carcasses were observed to be markedly enlarged. Slightly congested spleens were seen in all the four chickens. The bursae of Fabricius of all the birds were grossly enlarged and oedematous (Fig 2). A post mortem diagnosis of IBD was therefore made from these findings.

Laboratory Findings

Virology:

The bursa of Fabricius, heart, lung and spleen tested positive for IBD antigen by agar gel precipitin test (AGPT)

Bacteriology:

The samples of liver, lung and spleen submitted for bacteriology did not yield any bacterial growth during 24-48 hours of incubation.

Histopathology:

Section of the bursa of Fabricius (Figure 3) showed loss of the normal corticomedullary architecture of bursa and extensive expansion of the interfollicular connective tissue with edema and cellular infiltration by heterophils, macrophages and plasma cell. Lymphocyte depletion was observed in most follicles, in addition to medulla necrotic debris.

Parasitology:

Parasitologic result revealed that no helminth ova or coccidia oocysts.

Discussion

Gumboro disease is characterized by short incubation period of 2-3 days, and course of 5-6 days. Hemorrhages in skeletal muscles, proventriculus and enlargement of the bursa of Fabricius are some of the common lesions seen at post mortem (Lukert and Hitchner, 1997). In this report, the post mortem findings and death pattern observed were consistent with Gumboro disease. The diagnosis was confirmed by histopathology and IBD antigen detection in the bursa of Fabricius, liver, lung and spleen. This in effect implied an IBD outbreak in a double vaccinated 13 weeks old flock. Similar findings in vaccinated mature flocks aged between 16 and 20 weeks have been previously reported in Nigeria (Okoye and Ozoukwu, 1981; Durojaye et al., 1984, Awolaja and Adene, 1995). Such IBD outbreak therefore raised crucial question on the involvement of vaccine failure or vaccine break. In highly susceptible and unvaccinated flock, morbidity associated with the disease is usually 100% with mortality of 20-30% sometimes reaching 100% by very virulent IBDV. The 48.9% mortality recorded in this report suggested that the stock was fully susceptible to Gumboro disease.  Infectious bursal disease is largely controlled by both live attenuated and inactivated (killed) vaccines and there is no report of any successful drug therapy.

The administration of Conflox (Enrofloxacin), an antibiotic, by the farmer on day two of the outbreak could not ameliorate the condition as IBD is non bacterial. The action of this farmer was out of desperation and it also exemplified how drugs are used indiscriminately in poultry. Antibiotic treatment in this flock could be responsible for the inability to isolate any bacterium from the samples submitted for bacteriology.

The occurrence of coccidiosis in the flock and IBD after 12th week of age could be an indication of poor management practice by the farmer, especially as some of them were emaciated. Vaccination at 7th day post hatch without screening for maternal antibody may be one of the sources of the problem because maternal derived antibody might have possibly neutralized the vaccine virus.  Again, at 13th week, IBD vaccinal immunity, if any in this flock could have waned drastically and such a flock would be susceptible to IBD virus infection in the pen or to cross infection from adjacent sources. Loss of vaccine potency due to cold chain storage failure could be one of the possible factors that attributed to the flock’s susceptibility to IBD outbreak. There is therefore the need to maintain cold chain at (4ºC) for vaccines from point of production to point of administration. However, this situation is often difficult to attain in most developing countries of tropical Africa including Nigeria because of erratic power supply (Masiga et al., 1988).

Vaccine break from insufficient attenuation of vaccine or from vaccine virus reversion was ruled out from causative factors because outbreaks from such circumstances would have occurred shortly after vaccination. The outbreak in this case came 70 days post vaccination. Other probably and remote factors could be associated with emergence of pathotype variants which could overcome the current IBD vaccine immunity.

It was therefore, concluded that the IBD outbreak was possibly due to vaccine failure.

Recommendations

The development of IBD thermostable vaccine is advocated in view of the adverse effect of tropical environmental temperature and problems with cold chain maintenance (Alders, 2002). Studies should be directed towards elucidating the monitoring of IBD pathotypes in our environment. Birds should be routinely sero-monitored in order to know the level of protective anti bodies against IBD and for the planning of IBD vaccination regimen. Poultry farmers should be advised on the need for good management practices. 

 

Recommendations

The development of IBD thermostable vaccine is advocated in view of the adverse effect of tropical environmental temperature and problems with cold chain maintenance (Alders, 2002). Studies should be directed towards elucidating the monitoring of IBD pathotypes in our environment. Birds should be routinely sero-monitored in order to know the level of protective anti bodies against IBD and for the planning of IBD vaccination regimen. Poultry farmers should be advised on the need for good management practices. 

 

                                              Figure 1: IBD Mortality chart

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                                                        Figure 1: IBD Mortality chart

 

 

 

 

 

 

 

 

 

Figure 2: Haemorrhages at proventricular junction (A), Oedematous bursa of Fabricius

 

 

 

 

 

 

 

 

 

 

 

 

 

Acknowledgements

The authors acknowledge Professor D. F. Adene for initiating and supervising this study and publication. We are also grateful to Dr P. Okewale for facilities and his support.

 

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       

 

 

 

 

 

 

 

 

 

 

Figure 3: The lesions in the bursa of Fabricius (x100, H&E )

A: Ghost bursal follicles with necrotic medullary debri; B: interfollicular

oedema with heterophils and macrophages; C:Residual cortical tissues.

 

 

 

 

 

 

Acknowledgements

1. The authors acknowledge Professor D. F. Adene for initiating and supervising this study and publication. We are also grateful to Dr P. Okewole for facilities and his support.                                                                                                           

Conflict of interest statement

None of the authors of this paper has a financial or personal relationship with other people or organizations that could inappropriately influence or bias the content of the paper.

 

References

Awolaja, O. A. and Adene D. F. (1995). Infectious bursal disease outbreak in a vaccinated poultry flock. Tropical Veterinarian 13:1-2, Pp 37-44.

Brown, F. (1986). The classification and nomenclature of viruses: Summary of results of meeting of the international committee on Taxonomy of Viruses in Sendai. Intervirology 25:141-143.

Cosgrove, A. A. (1962). An apparently new disease of chicken-avian nephrosis. Avian Dis., 6:385-389

Dobos, P., Hill, B. J., Hallet, R., Kells, D. T., Becht, H. and Teninges, D. (1979). Biophysical and biochemical characterization of five animal viruses with bisegmented double- stranded RNA genomes. Journal of Virology 32:593-605

Durojaye, O. A., Ajibade, H. A. and Olafimihan, G. O. (1984). An outbreak of Infectious bursal disease in 20-week old birds. Tropical Veterinarian 2:175-176.

Johnson, D. C., Lukert, P. D. and Page, K. R. (1980). Field studies with convalescent serum and infectious bursal disease vaccine to control turkey coryza. Avian Dis. 24:386-392).

Lukert, P. D and Hitchner, S. B. (1997). Infectious bursal disease. In: Diseases of poultry 10th editon. Edited by Calnek, B. W., Barnes, H. J., Beard, C. W., McDougald, L. B. and Saif, Y. M. Iowa State University Press, Ames, 721-738.

Masiga, W. N., Halpin, B. and Cheneau, Y. (1988). A review of riderpest and riderpest-like diseases in Africa. A. O. Williams and W. N. Masiga ed. CTA of ACP/EEC (Lome Convention). Pp 1-68.

McFarran, J. B., McNulty, M. S., McKillop, E. R., Conner, T. J., McCracken, R. M., Collins, D. S. and Allan, G. S. (1980). Isolation and serological studies with infectious bursal disease virus from fowl, turkey and duck: Demonstration of a second serotype. Avian Pathology 9: 395-404

Ojo, M. O., Oduye, O. O., Nobi, L. and Idowu, A. L. (1973). Gumboro-like disease in Nigeria. Tropical Animal Health, Production, 5:52-56.

Okoye, J. O. A. and Ozoukwu, M. (1981). An outbreak of infectious bursal disease among chickens between 16 and 20 week old. Avian Disease 25:1034-1038.

Onunkwo, O. (1975). An outbreak of infectious bursal disease (IBD) of chickens in Nigeria. Veterinary Record 97:433.

 

About the Author

Dashe, Y. G*., Okewole, P., Jwander, D. L. and Alesa, M. U.
Central Diagnostic Department, P.M.B.01, NVRI, Vom, Nigeria
*Corresponding Author: e-mail: yakubudashe@yahoo.co.uk; phone: +234 8035778490

When will my guinea fowl start to lay?

Hi!!! i just got 3 Guinea hens and 1 cock (Grown) yesterday and i was wandering, when will they start to lay and possibly mate and lay on eggs? also they don't go up their ramp to the barn in less i put them in it anyways is it just because its new surrounding's ?
also a few tips on taming them they are kinda scared Thanks.

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