Hong Kong’s health authorities on Saturday confirmed the city’s first local case of human infection of rat Hepatitis E virus this year, urging the public to take effective rodent prevention and control measures.

The Centre for Health Protection said the patient is a 42-year-old man with chronic liver diseases. During a follow-up checkup at a private hospital on May 5, he was found to have abnormal liver functions, and was admitted to the Queen Mary Hospital the same day for further examination.

“The patient’s blood samples tested positive for rat HEV. His condition was stable and was discharged yesterday (on Friday),” the center said, adding that three contacts at his home are asymptomatic and will be put under medical surveillance.

The CHP’s epidemiological investigation showed that the patient lives in Hung Hom and works in the same district. He had reported no direct contact with rodents or rats, and had not seen rats at his residence or workplace. The man had visited various destinations in April this year, but no cases of the rat Hepatitis E virus have been reported in those destinations so far.

“Based on current epidemiological data, the CHP believes the infection was more likely to have been acquired locally. The center does not rule out the possibility that the patient might have indirectly come into contact with places or food contaminated by rats or their excreta during the incubation period,” the center said.

Investigations into the source and route of infection are ongoing.

Staff of the CHP and the Food and Environmental Hygiene Department have jointly conducted field inspections of hygiene conditions near the patient’s home, workplace and daily commute route, with minor signs of rodent activity detected at refuse collection rooms there.

Urging property management companies to improve hygienic conditions on premises, the department said they’ll arrange for cleaning and disinfection work to be carried out, and enhance rodent prevention and control work in the vicinity of locations visited by the patient.

The CHP said the possible routes of transmission of rat Hepatitis E virus to humans include ingestion of food or water contaminated by rodents or their excreta, exposure to environments or objects contaminated by rodents or their excreta, and direct contact with rodents or their excreta. The virus that usually causes human infection is mainly transmitted through the fecal-oral route.

Hong Kong had recorded an average of zero to two cases of rat HEV annually from 2021 to last year.

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The CHP reminded residents to eliminate sources of food and nesting places for rodents in the living environment, and store all refuse and food remnants in dustbins with well-fitted covers to prevent rodents, such as rats, from transmitting multiple diseases to humans.