Wild boars are reservoir of HEV: High prevalence among forestry workers in eastern France

Nearly one third of forestry workers in parts of eastern France are infected with Hepatitis E virus (HEV), according to a paper in the September Journal of Clinical Microbiology. Wild boars in the same region are also heavily infected. HEV is endemic in developing nations, but heretofore, HEV infection in industrialized nations has been most closely correlated with travel to developing nations.

The prevalence of HEV was found to be 14 percent among wild boar, about half that in pigs, says principal investigator Pierre Coursaget of the University of Tours, France. An earlier study found 12 percent prevalence among boar in The Netherlands. Among humans in the current study, the prevalence of anti-HEV antibodies increases with age, and varies with occupation and geographic location within eastern France. "The frequency of HEV infections in humans did not correlate with the number of pigs, locally, but there is good correlation with the number of car accidents due to wild boars," a surrogate for contact between humans and wild boars, says Coursaget. 

HEV is transmitted orally and fecally, with mortality rates of 1-3 percent in the general population, rising to 20-25 percent among pregnant women. In developing countries, outbreaks appear to arise from fecally contaminated water supplies. In Japan, and in Europe, consumption of wild boar or liver is associated with a high risk of acquiring hepatitis E virus infection, according to the report. However, the fact that HEV is absent among children in France suggests that eating ham is safe. Coursaget says the immune system in healthy people generally eradicates the infection, and that it is not sexually transmitted. 

Deer also are known to be infected with HEV, says Coursaget. "People in contact with HEV-infected animals or their environment must be aware of the possibility of HEV infection," he says. He is currently studying HEV infection in forestry workers, veterinarians, and pig farmers in different regions of France, in an effort to quantify risk factors. The current study also compared several antibody tests for HEV, with one, the HEV ELISA test, from MP Biologicals, proving superior to the other two.