New research suggests that pigs may function as a transmission vehicle for a strain of the hepatitis E virus (HEV) common in rats that has recently been found to infect humans. The Rocahepevirus ratti strain is called “rat HEV” because rats are the primary reservoir of the virus. Since the first human case was reported in a person with a suppressed immune system in Hong Kong in 2018, at least 20 total human cases have been reported, including in people with normal immune function.
People infected with rat HEV did not report exposure to rats, leaving the cause of infection undefined. The suspected cause during other human HEV infections, in many cases, is consumption of raw pork — making it a potential route for rat HEV as well.
Researchers have found that a strain of rat HEV isolated from humans could infect pigs and was transmitted among co-housed animals in farm-like conditions. Rats are common pests in swine barns — suggesting that the pork production industry may be a setting in which rat HEV could make its way to humans. The study was published recently in PNAS Nexus. Hepatitis E is the leading cause of the acute viral liver infection in humans worldwide, mostly in developing regions where sanitation is poor.
One strain linked to human disease is known as LCK-3110. The researchers used the viral genomic sequence to construct an infectious clone of LCK-3110. The team first showed the cloned virus could replicate in multiple types of human and mammal cell cultures and in pigs. Researchers then injected pigs with an infectious solution containing the LCK-3110 strain or another HEV strain present in pigs in the U.S., as well as saline as a control condition.
Viral particles in the blood and feces were detected one week later in both groups receiving HEV strains, but levels were higher in pigs infected with rat HEV. Two weeks later, co-housed pigs that received no inoculations also began to shed rat HEV virus in their feces — an indication the virus had spread through the fecal-oral route.
Published – September 28, 2024 09:10 pm IST
