Genetic Characterization of Avian Influenza Virus Isolated from Infected Commercial Duck in Sidenreng Rappang, South Sulawesi in 2016

摘要

Before outbreaks of avian influenza (AI) among commercial laying duck in Central Java in 2012, duck were considered as reservoir of this virus, the outbreaks reveals that duck were also susceptible for AI infection. The outbreaks among laying ducks in 2012 were caused by AIV subtype H5N1 clade 2.3.2, which is an introduction of new clade of AIV in Indonesia. After the first outbreak, new clade 2.3.2 were spread all over the country, and not only infected duck but also commercial chickens. Sidenreng Rappang is a district at South Sulawesi which have many laying duck farms. On 2016, there is AI outbreaks at most of the duck farms. Our study aim to characterize AIV isolated from outbreaks among laying duck in Sidenreng Rappang. Twenty five cloacal swab samples were randomly collected from seven commercial laying duck farms in Sidenreng Rappang during AI outbreaks on 2016. Samples from each farm were pooled into one sample pool, so that eventually there were seven samples pool. Samples were isolated on specific antibody negative (SAN) embryonated chicken eggs, then followed by identification of AIV subtype H5 and N1 using reverse transcriptase-polymerase chain reaction (RT-PCR). Then the PCR product were sequence for HA gene using primer H5-1: 5'-GCC ATT CCA CAT ACA CCC-3' and H5-3: 5'-CTC CCC TGC TCA TTG CTA-3' to determine pathogenicity and clade of these viruses. RT-PCR result showed that all seven isolates were AIV subtype H5N1. Sequencing result of HA gene at cleavage site of all isolates showed pattern "P-Q-R-E-R-R-R-K-R-G-L-F", Based on sequencing result, all AIV isolates were belong to high pathogenic AIV clade 2.3.2. In summary, our result showed that high pathogenic AIV clade 2.3.2 were already circulating in Sidenreng Rappang, indicating the necessity of AIV control programme among laying ducks in South Sulawesi.