PATHOLOGICAL AND SEROLOGICAL EVALUATION OF SOME INFECTIOUS BURSAL DISEASE VACCINES AND NIGERIAN FIELD VIRUS STRAIN ON SOME IMMUNE ORGANS OF COCKERELS
PATHOLOGICAL AND SEROLOGICAL EVALUATION OF SOME INFECTIOUS BURSAL DISEASE VACCINES AND NIGERIAN FIELD VIRUS STRAIN ON SOME IMMUNE ORGANS OF COCKERELS
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Date
2015-05
Authors
RAJI, Abdullahi Abdullahi
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Abstract
Infectious bursal disease (IBD) is an economically important disease to the poultry industry, with adverse effects on the immune system of the birds. The efficacy of most of the vaccines used in the control of IBD and pathology associated with the use of these vaccines in Nigeria is not clearly understood. Thisstudy was designed to compare pathological and serological changes in cockerels vaccinated with different IBD vaccines and those infected with the field infectious bursal disease virus (IBDV) strain. Serology, gross pathology and histopathologic changes caused by 3 intermediate vaccines MB®, Bursine 2®,Infectious Bursal Disease Vaccine® and Cevac® IBD L (Intermediate Plus strain), were evaluated and compared with those of field IBDV strain and control. Serum antibody titres, gross and histopathologic changes were monitored at 1, 2, 3, 4 and 5Days postvaccination/challenge (Dpv/c) and on the 7th, 10th, 14th and 21st days post vaccination/challenge (dpv/c). The titres of maternally derived antibody (MDA) are protective against IBD for a period ranging from 27 to 40 days post hatch was determined based on calculation of optimal vaccination time (OVT). ELISA test follow-up post vaccination/challenge (pv/c), gave a detectable antibody titre (3.492±0.72 to 4.480±0.03) indicating protection or MDA against IBDV in the vaccinated and control groups respectively, and infection with IBDV in the challenge group.At 3 Dpv/c, petechial and ecchymotic haemorrhages in thigh, keel muscles, and spleen were observed in all the groups with degree of variation except the control. Cevac® IBD L and field virus had a significant difference (p<0.05) in spleen relative weight (SRW) and spleen body weight ratio (S:BW). Bursa body index (BB Index) presented 0.3-0.7 index (relative transient atrophy) and a strong atrophy (< 0.3) with the field IBDV strain on 7Dpv/c to
14Dpv/c. Histopathologic lesion scores recorded from bursa, spleen and thymus, showed that birds vaccinated or challenge withMB®, Cevac® IBDL and challenge had similar degree of injury, whereas Bursine 2® and Infectious Bursal Disease Vaccine®were slightly different, but not statistically significant (p>0.05). In general, bursa, spleen and thymus lesions scores were statistically significant (P<0.05). These findings suggest that intermediate vaccines are capable of causing bursal injuries. Bursallesions and rise in antibody titre against IBDV after vaccination/challenge were similar, and may be confused with field virus-induced lesions.The intermediate plus strain or an intermediate with moderate to high residual pathogenicity should be used in vaccinating birds against IBD in highly IBD endemic areas
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A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF MASTER OF SCIENCE DEGREE IN VETERINARY PATHOLOGY
DEPARTMENT OF VETERINARY PATHOLOGY, AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA
Keywords
PATHOLOGICAL,, INFECTIOUS BURSAL DISEASE VACCINES,, NIGERIAN FIELD, IMMUNE ORGANS,, COCKERELS., VIRUS STRAIN,, SEROLOGICAL EVALUATION,