Abstract

Seroprevalence of Newcastle disease in layer chickens and pathology in clinically affected chickens at Gazipur, Bangladesh

Authors: Sayed Mohammad Abu, Noor Monira, Husna Asmaul, E-Elahi A.T.M. Mahbub, Kamal Abu Hena Mustafa and Rahman Md. Masudur

DOI: http://dx.doi.org/10.71081/cvj/2022.005

Abstract
The goal of this study was to determine the seroprevalence of Newcastle disease (ND) and to evaluate the age based effectiveness of three commonly used ND vaccines (Cevac New-L, Avenew and Newcastle Disease vaccine) in commercial layer chickens in Bangladesh using hemagglutination inhibition (HI) test. Additionally, postmortem and histopathological examinations were also performed in 10 clinically affected chickens to elucidate major pathological changes in different organs. For seroprevalence study, total 200 sera (grower 80 and layer 120) were collected randomly from 20 different vaccinated layer farms (10 grower and 10 layer) and for detection of ND vaccine efficacy, a total of 100 sera were randomly collected from 10 commercial non-vaccinated grower and layer farms (10 birds in each farm) located at Gazipur district from January to June-2020. The overall seroprevalence of ND was 21% followed by, 10% in grower stage (12-16 weeks) and comparatively higher seroprevalence, 26.6%, in layer stage (27-40 weeks). In case of detection of age based vaccine efficacy, blood serum samples were collected at 7 th and at 14 th day post vaccination (dpv) to determine Ab titre of experimental grower and layer chickens. The mean titer at 7 th and 14 th dpv in both grower and layer groups were meaningfully greater (P<0.01) in comparison to chicken groups before vaccination. Moreover, the GMT of grower chickens were 2 7.2 -7.6 and 2 8.00 -8.1 at 7 dpv and 14 th dpv, respectively and in case of layer chickens it was slightly higher, 2 9.1- 9.2 and 2 9.6 -10 at 7 dpv and 14 dpv, respectively. In case of pathological findings, affected chickens showed characteristic gross and microscopic lesions particularly in proventriculus, trachea, liver and cecal tonsils. These finding may assist epidemiologist to take appropriate preventive and control strategies against the disease.

Keywords: Newcastle Disease, Seroprevalence, Vaccine, Pathology, Layer chicken, Bangladesh