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Just over a year ago Hong Kong University identified the first human infection with a rat Hepatitis E virus (see ECDC CDTR Notice) in an elderly immunosuppressed individual who had recently received a liver transplant.
The announcement from HKU reads, in part:
HKU discovers that rat hepatitis E virus can cause hepatitis in humans
28 Sep 2018
Rat hepatitis E virus (rat HEV) was first discovered in 2010 and circulates in house rats (Rattus rattus) and sewer rats (Rattus norvegicus). It is very distantly related to human hepatitis E virus variants. Human infection by rat HEV has never been documented previously.
A study led by Professor Yuen Kwok-Yung, Henry Fok Professor in Infectious Diseases, Chair Professor of Infectious Diseases, and Dr Siddharth Sridhar, Clinical Assistant Professor at the Department of Microbiology of Li Ka Shing Faculty of Medicine, The University of Hong Kong (HKU) has discovered for the first time that rat HEV can infect humans.Since then, we've seen more than a half dozen cases identified in Hong Kong (see June's Hong Kong Reports 6th Human Infection With Rat Hepatitis E Virus), along with a single case reported in Canada detected in a person with recent travel history to Africa (see Rat hepatitis E may be ‘under-recognized’ cause of hepatitis infection).
It remains unclear just how widespread transmission really is, or how people are being infected. While apparently still rare, today Hong Kong's CHP announced the discovery of yet another human infection.
CHP investigates case of human infection of rat Hepatitis E virus
The Centre for Health Protection (CHP) of the Department of Health is today (November 21) investigating a case of human infection of rat Hepatitis E virus (HEV) and urged members of the public to be vigilant against hepatitis E infection and to strictly observe good personal, food and environmental hygiene.
The case involves an 82-year-old woman with underlying illnesses, who had presented with jaundice, poor appetite and tea-coloured urine since October 7. She was admitted to Queen Elizabeth Hospital on October 21 and was discharged after treatment. The patient is now in a stable condition. Her blood sample tested positive for rat HEV upon laboratory testing.
The CHP's epidemiological investigations revealed that the patient resided in Kowloon City District. She could neither recall having direct contact with rodents or their excreta, nor had noticed rodents in her residence. She had no travel history during the incubation period and her home contacts have remained asymptomatic so far.
"Based on the available epidemiological information, the source and the route of infection could not be determined. The CHP's investigation is ongoing," a spokesman for the CHP said.(Continue . . . )
"The CHP has already informed the Pest Control Advisory Section of the Food and Environmental Hygiene Department about the case to carry out rodent control measures and a survey as appropriate," the spokesman added.
The exact mode of transmission of rat HEV to humans is unknown at the moment. Possible routes of transmission 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 usual HEV causing human infection is transmitted mainly through the faecal-oral route.
To prevent hepatitis E infection, members of the public should maintain good personal, food and environmental hygiene. For example, they should wash hands thoroughly before eating, store food properly or in the refrigerator, not leave food at room temperature for a long time, and use 1:99 diluted household bleach for general household cleaning and disinfection as household detergent may not be able to kill HEV. High-risk individuals, such as elderly persons with a major underlying illness (especially those who have undergone organ transplantation), pregnant women, patients with chronic liver disease and patients with Glucose-6-Phosphate Dehydrogenase Deficiency (also known as G6PD Deficiency), who are infected with HEV may develop a serious illness, so they should exercise extra caution.
Hong Kong has a notorious`rodent problem', and following last May's announcement of 3 new Rat Hepatitis E cases, HK's Food and Health Bureau announced a massive cleanup campaign. Last August it was announced that the Territory-wide cleaning operation would be extended to mid-November.
A progress report - released less than a week ago - indicates this effort will now be extended into early 2020.
Anti-rodent work continues to be stepped up (with photo)
The interdepartmental Pest Control Steering Committee met today (November 15) to review the effectiveness of the work under the territory-wide cleaning operation since May 20. To sustain the effectiveness of anti-rodent work, various departments agreed to strengthen the relevant work until February next year.
Meanwhile, owing to the first confirmed local dengue fever case recorded this year in early November, the departments also discussed areas to be strengthened when carrying out anti-mosquito work next year.
Various departments briefed the meeting on the progress of anti-rodent work in all 18 districts.
The Food and Environmental Hygiene Department (FEHD) has collected 11 617 dead rodents, caught 9 349 live rodents and filled 5 102 rat holes from May 20 to November 10. The FEHD has stepped up rodent control work in various districts. In comparison with the figure in May, the number of live rodents caught in October has increased by 27 per cent and the number of complaints received has dropped by 48 per cent.
Between January and October this year, the FEHD caught 19 106 live rodents and filled 10 831 rat holes, whereas in the same period last year, 13 264 live rodents were caught and 7 698 rat holes were filled, representing an increase of around 40 per cent.(Continue . . . )
Hong Kong is one of the most densely populated cities in the world, with 7.4 million people crammed into 427 square miles (1,110 square kilometers). While that works out to just over 6,600 people per sq. km., the territory's population is far from evenly dispersed.
In 2014, Hong Kong's government estimated that Kwun Tong, with 57,250 persons per sq. km., was the most densely populated district in the territory.Add in its close proximity to, and continual traffic from, Mainland China and Hong Kong becomes an important region for epidemiological surveillance.
While rat hepatitis E hasn't shown much in the way of epidemic potential, we still know very little about disease's prevalence and epidemiology, and so we follow these reports with considerable interest.
