A seroepidemiologic study of Reston ebolavirus in swine in the Philippines

Background: Ebola viruses cause viral hemorrhagic fever in humans and non-human primates and are endemic in Africa. Reston ebolavirus (REBOV) has caused several epizootics in cynomolgus monkeys (Macaca fascicularis) but is not associated with any human disease. In late 2008, REBOV infections were identified in swine for the first time in the Philippines. Methods: A total of 215 swine sera collected at two REBOV-affected farms in 2008, in Pangasinan and Bulacan, were tested for the presence of REBOV-specific antibodies using multiple serodiagnosis systems. A total of 98 swine sera collected in a non-epizootic region, Tarlac, were also tested to clarify the prevalence of REBOV infection in the general swine population in the Philippines. Results: Some 70 % of swine sera at the affected farms were positive for REBOV antibodies in the multiple serodiagnosis systems. On the other hand, none of the swine sera collected in Tarlac showed positive reactions in any of the diagnosis systems. Conclusions: The high prevalence of REBOV infection in swine in the affected farms in 2008 suggests that swine is susceptible for REBOV infection. The multiple serological assays used in the study are thought to be useful for future surveillance of REOBV infection in swine in the Philippines.