An investigation of classical swine fever virus seroprevalence and risk factors in pigs in Timor-Leste.

Classical swine fever virus (CSFV) is a highly infectious pathogen of pigs and believed to be a major constraint to pig production in Timor-Leste. The Ministry of Agriculture and Fisheries conducts vaccination campaigns in an attempt to control clinical disease, however, there is no empirical data available concerning the seroprevalence and distribution of CSFV in Timor-Leste. To help address this knowledge deficit, a cross-sectional study to determine seroprevalence was conducted in the three districts that border Indonesia. Data on farmer- and pig-level factors were also collected to look at their impact on CSFV serological status. Overall, true CSFV seroprevalence was estimated at 34.4%. Seroprevalence estimates varied widely between and within districts, subdistricts, and villages. Older pigs and pigs that had been vaccinated for CSFV were more likely to test positive for CSFV antibody. Pigs owned by farmers that experienced the sudden death of pigs in the 12 months prior to the survey were more likely to test positive for CSFV antibody, while pigs that had been sick in the previous three months were less likely to test positive for CSFV antibody. The final multivariable model accounted for a large amount of variation in the data, however, much of this variation was explained by the random effects with less than one percent of the variation explained by the fixed effects. This work further supports the need for a collaborative approach to whole-island CSFV control between West Timor, Indonesia and Timor-Leste. Further work is needed to better understand the risk factors for CSFV serological status in order to allocate resources for control. As CSFV is now endemic in Timor-Leste research involving a combination of serology, antigen detection and in-depth investigation of suspect cases over a period of time may be required.