Researchers from the Health, Labor and Welfare Ministry have identified a high prevalence of hepatitis E in the Chugoku area’s population of wild boars, the ministry said on Wednesday.
A group of researchers monitoring wild animals captured in various areas across Japan discovered that over 30 percent of the population of wild boars in the Chugoku area have a history of, or have been infected with, strains of the hepatitis E virus (HEV).
The ministry has warned the public against consumption of raw wild boar meat, saying the virulent HEV strains can be easily transmitted to people.
It also said that sanitation control methods will be scrutinized during meetings that are to begin Thursday.
“Gibier,” which is the French term for game, is considered a delicacy and has been enjoying popularity in many regions of Japan, where it is sold as a local specialty as part of regional revitalization efforts.
However, inspection requirements for the slaughtering and processing of game have not yet been defined and regulated by law, leaving distributors to create their own guidelines.
The researchers are conducting a study, launched in 2009, that will last 13 years. It’s aimed at testing blood samples from wild boars hunted in designated areas across Japan.
The results have shown that HEV infection was prevalent among 113 animals, which account for 42 percent of wild boars captured in the Chugoku area between 2009 and 2011. The ministry said the number of infections was higher than in the previous years and HEV genomes had been detected in blood samples from 4 percent of the total number of wild boars caught.
The researchers found the genotype strains of the HEV resembled those detected in several samples taken from people in Shimonoseki, Yamaguchi Prefecture, in 2011, leading them to speculate the strain could have been transmitted to humans.
As many as 76 wild boars or 30 percent of the total number of the animals hunted in Chugoku in 2012 and 2013 had been infected with HEV.
The study also showed that the prevalence of HEV infection in wild boars was found to be 22 percent in the Kyushu region and was detected in 46 boars. In the Kanto area, the number of infected animals was 152 or 8 percent of the total captured there. The researchers also inspected samples from 71 boars in the Kinki area, but have not detected strains of the virus.
The ministry, which also verifies blood samples from wild deer captured in Chugoku, said 209 animals, or 0.5 percent of the total, had been infected with the virus.
According to the Food Safety Commission of Japan, seven cases where consumption of raw wild boar and 11 cases where consumption of wild deer might have been the cause of HEV infections were reported between 2000 and 2008.
“We need to find measures to help local communities implement unified standards,” said Kitasato University professor Shinji Takai, of the ministry’s research team.
He added that standards for slaughtering, processing and consuming game should be revised with consideration for local food and hunting cultures.
The symptoms of infection caused by HEV develop in about six weeks and include fever, abdominal pain. Pregnant women and the patients are at a greater risk of complications from HEV infection.