Routes of Transmission of Swine Hepatitis E virus in Pigs

Abstract

Hepatitis E virus (HEV) is believed to be transmitted by the fecal-oral route in pigs. To date, HEV has been transmitted experimentally by the intravenous or intrahepatic route. To assess the possible route (s) of HEV transmission, tonsil/nasal secretions, use of contaminated needles, or fecal-oral exposures were simulated in a swine bioassay. Three positive-control pigs were inoculated intravenously with swine HEV and served as the source of biological samples (tonsil/nasal secretion swabs, bloodcontaminated needles, or pooled fresh feces) to be used as inocula in the swine bioassay. Three uninoculated pigs were placed with the positive-control pigs and served as contact controls. Weekly fecal and serum samples from each exposed pig were tested for anti-HEV antibodies and HEV RNA to confirm HEV infection. All positive-control and contact-control pigs became infected. One of three fecaloral exposed pigs shed the virus in feces and seroconverted. Three pigs exposed to the tonsil/nasal secretion swabs and the three pigs exposed to the contaminated needles remained negative. The fecal-oral route of transmission was confirmed in pigs. It is less likely that HEV is transmitted via contaminated needles or tonsil/nasal secretions.