Prevalence and Risk Factors of Swine Influenza Virus in Pig Farms, in West Java, Banten and Jakarta during 2016-2017

Abstract

The following extensive H5N1 outbreaks in poultry in Indonesia, interest increased in identifying influenza A virus subtypes circulating amongst local pig productions. Pigs have been traditionally proposed as a “mixing vessel” where reassortant influenza strains can arise. Swine influenza (SI) infection has major economic impact on pig farming and is a zoonotic virus of public concern. Consider with the risk of swine influenza virus (SIV) infection, we conducted a study to determine prevalence in the farm, collector and slaughterhouse, and risk factors in the farm in West Java, Banten and Jakarta provinces. Data consisted of SIV status at pig farms (n=175), collectors (n=11) and slaughterhouses (n=34), based on serological test and farm data from questionnaire collected during national surveillance program. The association between risk factors and the SIV status in the farm level was determined using univariable and multivariable logistic regressions. The results showed that seroprevalence at farm 30.85% (95%CI: 24.48-38.05), collector 18.18% (95%Cl: 5.13-47.69) and slaughterhouse 35.29% (95%Cl: 21.48-52.08). The risk of farms detected SIV seropositive increased when: farmers have other animals in the farm (Odds ratio (OR) = 2.78; 95% CI: 1.21-6.38); holding pig less than two years (OR = 3.64; 95%Cl: 1.25-10.58); distance to poultry farm less than one km (OR = 2.42; 95%Cl: 1.11-5.24) and farmers who bought pig only from collectors had the highest risk for SIV seropositivity (OR = 9.03; 95%Cl: 3.62-22.52). This study highlights that targeting surveillance in high density of pig and poultry population area could enhance the number of farm detected for SIV.