Study of Newcastle Disease Virus (VND) Infection on ducks and chickens in Areas of Subang district

Posted by Sekilas Peternakan on

Tuesday, 5 December 2017

APRIZAL PANUS. Study of Newcastle Disease Virus (VND) Infection on ducks and chickens in Areas of Subang district. Under the direction of SURACHMI SETIYANINGSIH and NI LUH PUTU IKA MAYASARI

Newcastle Disease (ND) is endemic in Indonesia, including in Subang district. Vaccination has been practised to control its high morbidity and mortality rate; however, cases are still reported. Investigation on the disease in Subang district is limited; diagnosis is generally determined based on clinical symptoms, pathological and serological findings.

The objectives of this research were to study Newcastle Disease virus (NDV) infection in Subang areas and to examine the diversity of the circulating ND viruses. The infection was determined by detecting NDV in swab samples and specific antibody in serum samples. Swabs of cloacal, oropharynx and serum were sampled from total of 149 ducks and 393 chickens in backyard farms and live bird markets located in 10 subdistricts. Real Time Reverse Transcription Polymerase Chain Reaction (rRT-PCR) matrix (M) was used to screen pools of 5–7 samples. Selected individual samples representing type of bird, sample, and location were inoculation in SPF embryonated chicken eggs following 2 passages. Specific antibody againts ND was tested by Haemagglutination Inhibition (HI). Characteristics of isolates were examined by HI test using LaSota and Komarov antisera, rRT-PCR fusion (F), and the elution time test.

The results showed NDV were detected in 19/67 (28.3%) cloacal and 8/67 (11.9%) pharyngeal pools of chicken samples; 18/67 (26.9%) of the pools excreted virus via cloaca and oropharynx, while the duck pools of 8/30 (26.7%) shed virus from cloaca. The routes of viral shedding was further shown by virus inoculation result. Characterization of 18 NDV isolates indicated that majority of them have homogeneous antigenic characteristic, only a few showed variations up to 2 Log2 and 4 Log2 with LaSota and Komarov antisera, respectively. The isolates had a higher affinity to Komarov antiserum indicating their propensity to virulent strains. This finding was supported by the elution patterns which grouped 3 isolates to mesogenic strain and 15 isolates to velogenic strain, and further confirmed by rRT-PCR F. Specific antibody was detected in 48 out of 408 (12%) birds with titres ranging from 1–8 Log2. Small percentage of vaccinated chickens (37/212) demonstrated protective titers. Analysis in 6 vaccinated flocks indicated poor vaccination responses. Eighteen of NDV isolates were found to have the majority of characters are relatively homogeneous, only a few isolates showed diversity of pathogenicity and antigenicity. Newcastle Disease vaccination in broiler chickens is suboptimal due to the uneven distribution of antibody titers. Newcastle disease was confirmed in 9 subdistricts, but absent in Cipeundeuy subdistrict which represented by a limited number of ducks. This study emphasis the need for further investigation employing bigger sample size and wider areas to provide a comprehensive information to the local government for better implementation of NDV prevention and control programs in poultry in Subang.

Keywords: Newcastle Disease, molecular detection, detection of virulence, Antigenic diversity, antibody

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