Potential use of oral fluid samples for serological diagnosis of African swine fever.

African swine fever (ASF) is a complex, highly lethal, notifiable disease of swine. ASF is wide-spread in sub-Saharan Africa and East European countries and there is presently a great risk of spread to neighboring countries. Since there is no vaccine for ASF virus (ASFV), control is based on rapid and early detection of the disease via surveillance. This approach requires collecting blood samples from large number of animals. Laborious and expensive of itself, this process also presents an additional risk because ASFV is present at high concentrations in the blood. The objective of this study was to initiate studies into the potential use of oral fluid as an alternative to serum for ASF diagnosis, for latter studying its possible use in surveillance and control programs. To this end, oral fluid samples collected at different times post infection from eight pigs experimentally inoculated with an attenuated ASFV were assayed using modified protocols of the two validated serological techniques, the enzyme-immune-liked assay (ELISA) and immunoperoxidase technique (IPT). Antibodies against ASFV were detected in oral fluid samples of all animals from early post infection through the end of the experiment by ELISA and IPT. These results confirmed the presence of ASFV antibodies in swine oral fluids samples, the possibility of an oral fluid-based approach in ASF diagnosis and, potentially in ASF surveillance.