Circulating H5N1 virus among native chicken living around commercial layer farms

Abstract

ABSTRAK Tarigan Sejak diterapkannya program vaksinasi kasus penyakit avian influenza (AI) H5N1 pada ayam pembibitan dan ayam ras petelur jarang terdengar. Penelitian in bertujuan menganalisis apakah redanya kasus tersebut berhubungan dengan hilangnya sumber infeksi di sekitar peternakan. Sampel serum dikumpulkan dari 421 ayam buras yang tinggal di sekitar peternakan ayam petelur di Kabupaten Cianjur dan Sukabumi, Jawa Barat pada Maret-April 2014. Antibodi virus AI H5N1 dianalisis dengan uji haemagglutination ihibition (HI), ELISA dan immunoblotting untuk mendeteksi antibodi terhadap haemagglutin virus H5N1, domain eksternal protein M2 (M2E) dan nukleoprotein (NP) virus AI. Sebanyak 8,6% dari ayam buras yang diperiksa seropositif terhadap virus AI berdasarkan satu atau lebih dari uji serologis. Hasil penelitian mengungkapkan bahwa virus H5N1 masih beredar pada ayam buras yang berkeliaran disekitar kandang ayam ras petelur. Sera yang positif dengan uji HI, M2E dan NP ELISA berturut turut 2,4%, 3,3% dan 3,8%. Tidak terlihat kesesuaian antara hasil satu uji dengan uji lainya. Penyebab ketidaksesuaian hasil tersebut diduga karena HI test, MM2e ELISA dan NP ELISA mengukur antibody yang berbeda yang kemunculan dan durasi masing masing antibodi tersebut berbeda. Kenyataan bahwa virus H5N1 masih beredar di sekitar peternakan ayam petelur menunjukkan bahwa ancaman virus AI masih membayangi peternakan ayam komersial dan karena itu vaksinasi dan biosekuriti yang ketat masih dibutuhkan. Soon after the application of vaccination programme against high pathogenic avian influenza H5N1 outbreak of the disease in breeder and commercial layer farms has diminished remarkably in West Java. This study aimed to investigate whether the H5N1 decline is related to the disappearance of source of infection around the farms. Serum samples were collected from 421 native chicken living around commercial layer farms in the Districs of Cianajur and Sukabumi, West Java in March-April 2014. Antibodies to avian influenza virus (AIV) H5N1 were measured using haemaglutination inhibition (HI), ELISAs and immunoblotting that measured presence of antibodies to the haemagglutin of H5N1 strain, as well as the M2e and nucleoprotein (NP) of all avian influenza viruses. Based on the combined results, 8.6% of the native chickens were seropositive to AI virus based on one or more of serological tests. This study provided serological evidence that H5N1 virus was still circulating among native chicken living around commercial layer farms. Many positive sera were however positive for antibodies in one test only: 2.4%, 3.3% and 3.8% by HI test, M2e and NP ELISA, respectively. It could be speculated that the incongruity of the results is due to the fact that HI, MM2e ELISA and NP ELISA all measure different type of antibodies and the duration of these antibodies in serum following infection with H5N1 differ. The fact that H5N1 virus is still circulating around commercial layer farms infers that the commercial farms are still under threat and therefore vaccination ...

Endemicity of avian influenza in ducks living around commercial layer farms

“…This is in contrast to the situation in AI-vaccinated, commercial layer farms in the area, where no AIV infection was recorded for the last 12 months (S. Tarigan personal observation). Further of interest was, that native chickens which were not vaccinated against AI and scavenging together with the ducks had much lower seroprevalence of AI (Tarigan et al 2015b).…”

“…In our previous study, we reported the presence of ongoing subclinical infection in native chickens. Thirty-six (8.6%) of the 421 chicken tested were positive in either one or more of three serological tests (HI, Influenza-A ELISA and MM2e ELISA) used (Tarigan et al 2015b). The purpose of this study was to assess the importance of ducks living around commercial farms as the source of AIV infection.…”