Haemorrhagic Fever with Renal Syndrome (HFRS)
What is HFRS?
Haemorrhagic Fever with Renal Syndrome, HFRS, is an acute zoonotic viral disease caused by the Hantaan virus. It is also called epidemic Haemorrhagic Fever or Korean Haemorrhagic Fever. The disease is widely prevalent in different places of the world, primarily in Far East Region of Russia, China, Korea, Japan, northern Europe and the Balkans. In China, the disease is found commonly in northeast, east, mid-south and south-west regions where in recent years, there are often outbreaks of HFRS caused by domestic rodents, mainly in spring and summer seasons. HFRS caused by wild rodents occurs mainly in the autumn harvest season.
Hantaan virus can be found in rodents, but does not cause illness. However, when it is transmitted to human beings, it can cause illness. The incubation period is usually 2 to 4 weeks, but could be as short as a few days. Symptoms include abrupt onset of fever, headache, orbit pain, back pain, erythema of face, neck and chest. Later it may proceed to exhibit bleeding signs, little urine output, renal failure, shock. Death could occur in as high as 15% of cases.
What' s the route of transmission for HFRS?
There are 4 main routes of transmission for HFRS:-
- Inhaling aerosols of rodent excreta. Believed to be the main mode in overseas countries.
- Direct contact of wound to rodent excreta or being bitten by rodents. Believed to be the main mode in the Mainland.
- Ingesting food contaminated by rodent excreta.
- Bitten by the vector rodent flea.
How to prevent HFRS?
Travellers to areas endemic of HFRS should adopt the following precautions:-
- Avoid visiting or living in places with poor environmental hygiene.
- Do not contact rodents or their excreta.
- Apply insect repellent on clothing, shoes and exposed skin.
- Do not sit or rest on grassland and hay stacks
- When camping, choose sites which are open and dry to lessen the chance of rodent invasion.
How to treat HFRS?
Early hospitalization and bed rest are most important. When in hospital, fluid management of the patient is critical to minimise the effects of shock and renal failure. If the latter sets in, dialysis is often required.
There is a vaccine available for prevention in Mainland and is recommended for residents in HFRS endemic areas.