Hepatitis E can be well contained in pigs

The hepatitis E virus (HEV) is common in pigs. The virus does not make pigs sick but they can transmit the virus to humans. This may happen, for example, when people come into contact with pigs or eat raw pork products that contain pork liver. In humans, the virus can cause abdominal pain, fever and inflammation of the liver. This prompted Marina Meester to investigate how pig farmers can limit the spread of the virus.

Remarkable differences

Meester examined slaughter pigs from 207 pig farms. HEV was found to be present at all of these farms: some of the pigs had an HEV infection or had had it in the past and were therefore now immune. There were notable differences between farms, however. Most pig farms delivered groups of pigs for slaughter with infection or immunity to HEV present in each group. Yet some farms were able to deliver groups of pigs without HEV. Meester then compared two farms that presented a large contrast. One farm was found to have the virus present in all pens, while the other managed to keep two of the three sections examined free of the virus. The difference was due to the hygiene measures this farm had in place.

Limiting spread

Pig farmers can take several measures to reduce the chance of the virus spreading. Examples include setting up separate sections to keep pigs apart, using clean boots and materials in each section and controlling flies and pests. These measures can cut back infections of pigs and thereby potentially reduce the transmission of the virus from pig to human. "A combination of measures is crucial here," Meester said. "If you only implement one measure, the virus will still get in another way."

Preparedness

Currently, there are few infections of people with HEV in the Netherlands and the risk to public health is low. Still, the study's findings are relevant. "We are now better prepared if the virus changes which may make it spread more rapidly among humans or cause more severe symptoms. In the past, we have seen that animal diseases can suddenly emerge in humans and we didn't quite know what to do then. With this research, we have increased preparedness for HEV outbreaks."

The challenge is that the measures only work if they are applied consistently. "Even if you forget a measure for just one day, the virus can come in and spread quickly between pens." Otherwise, the measures are not difficult to implement. So Meester's advice is to implement them as much as possible now. By doing so, pig farmers can not only contain HEV, but possibly also better control other pathogens.