Source: Hong Kong Government special administrative region – 4
The Centre for Health Protection (CHP) of the Department of Health today (September 30) is investigating a case of human infection of rat Hepatitis E virus (HEV). The patient is a family member of another case announced last week and the two cases are epidemiologically linked. The CHP once again urges the public to maintain good personal, food and environmental hygiene, and to implement effective rodent prevention and control measures to prevent rat HEV infection.
Case details
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Last week, the CHP recorded a rat HEV case involving a 91-year-old man with underlying illnesses. Since then, the CHP and the Food and Environmental Hygiene Department (FEHD) have been investigating the source and route of the infection. One of the male patient’s family members, an 80-year-old female, lives in the same Residential Care Home for the Elderly (RCHE) in Kowloon City District. Since the two also share a similar exposure history, the CHP prudently arranged for her to undergo a blood test. Upon laboratory testing by the Public Health Laboratory Services Branch under the CHP, her blood sample tested positive for rat HEV.
The female patient has not exhibited any symptoms of rat HEV and her condition remains stable all along. The CHP will arrange her to undergo further examination and assessment at a hospital.
According to the information provided by the patient, the RCHE staff and the patient’s family, the patient had no travel history during the incubation period and no direct contact with rodents, and no rats were observed in the RCHE. Apart from the meals provided by the RCHE, the patient dines at a restaurant in Homantin Plaza with her family at least once or twice a week. Family members of both patients, as well as other residents and staff of the RCHE, are currently asymptomatic and have been put under medical surveillance. No other confirmed cases have been identified so far. Based on the current epidemiological investigation, the CHP believes that it is more likely that patients were infected at the restaurant in question. The CHP does not rule out the possibility that the two patients came into indirect contact with places or food contaminated by rats or their excreta during the incubation period.
Followed an inspection last week, the FEHD conducted another inspection today at the restaurant the patients frequently visited. During the inspection, the FEHD found that the restaurant was still carrying out cleaning and disinfection, and provided staff of the restaurant with environmental hygiene education and advice on pest control. In accordance with the FEHD’s instruction, the restaurant suspended operations for thorough cleaning and disinfection, and rodent control work. The FEHD will continue to strengthen cleaning, disinfection and rodent control efforts in the public areas near the locations which the patients visited.
The CHP and the FEHD will also continue to investigate the source and route of infection of this case.
This is the fourth case of human infection of rat HEV recorded so far this year.
Symptoms of rat hepatitis E
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Human cases of rat hepatitis E virus infection affect mostly immunocompromised persons. Most cases are asymptomatic, while symptomatic patients reported mild symptoms, such as fatigue, abdominal pain and loss in appetite. It is less likely for patients with rat HEV infection to develop jaundice compared to HEV infected patients.
Prevention
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The possible routes of transmission of rat HEV 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 HEV that usually causes human infection is mainly transmitted through the faecal-oral route.
To prevent infection, the members of the public should maintain good personal, food and environmental hygiene. For example, they should wash their hands thoroughly before eating, store food properly or in the refrigerator, avoid leaving food at room temperature for a long time, and use 1:99 diluted household bleach for general household cleaning and disinfection as household detergents may not kill HEV.
The Five Keys to Food Safety should be adopted when handling food, i.e. Choose (choose safe raw materials), Clean (keep hands and utensils clean), Separate (separate raw and cooked food), Cook (cook thoroughly) and Safe Temperature (keep food at a safe temperature), to prevent food-borne diseases.
In general, rodents (such as rats) can transmit multiple diseases to humans, both directly and indirectly. The public is advised to take the following measures:
- Eliminate sources of food and nesting places for rodents in the living environments. Store food in covered containers and handle pet food properly to prevent it from becoming food for rodents;
- Store all refuse and food remnants in dustbins with well-fitted covers. Dustbins must be emptied at least once a day;
- Keep premises, especially refuse rooms and stairways, clean. Avoid accumulation of articles;
- Inspect all flower beds and pavements regularly for signs of rodent infestation; and
- Avoid the high-risk activities below to reduce rodent contact:
– Avoid contact with rodents and areas contaminated by rodent excreta;
– Avoid handling rodents with bare hands;
– Wash hands with liquid soap and water immediately after handling animals, and disinfect contaminated areas; and
– If a wound appears, clean the broken skin immediately and cover it properly with waterproof adhesive dressings.
Rodent control requires co-operation from all sectors of society. The CHP urged the public to strengthen rodent prevention and control measures and co-operate with government’s efforts to reduce the risk of rat HEV transmission.