Information on Hantavirus Infections

- What is hantavirus disease ?

Hantavirus disease is a viral infection acquired by man through contact with rodents. In Europe and Belgium, the prevailing form of hantavirus infection is called Nephropathia epidemica (NE). It is the mildest form of the disease compared with the Asian and American forms. The symptoms however, can be severe enough to require hospitalisation.

- Who is the host of the virus ?

In W-Europe and Belgium the main virus host is the Cletherionomys glareolus (red bank vole - figure1). This is a little rodent (8-12 cm) with a typical reddish back and grey flanks. It lives in leaftree woods with scrub vegetation under the trees, by preference on the edge of the forest, in parks and can occasionally enter human habitats during winter.

Figure 1 : Rosse woelmuis (Clethrionomys glareolus). Afbeelding afkomstig uit “Mammals” van M. CLARK, uitgegeven door Ham-lyn Children’s Books, met de toelating van Heinemann Educational Books.

- How is hantavirus transmitted ?

Humans acquire the infection by direct or indirect contact with rodents or their excreta. The infected rodents are apparently unaffected by the virus, but remain lifelong carrier of the virus. Infection occurs through inhalation of virus particles or through a bite. In Europe there is no evidence that hantavirus disease can be acquired by human-to-human transmission. Cases of hantavirus disease occur when rodent populations are increased and when this population is heavily infected by the virus.

Figure 2 : Evolutie van het aantal gevallen per 4 weken (1996-2002)
Bron : Referentielaboratorium

- Where are we at risk for hantavirus infection ?

In Belgium the area between Sambre and Meuse and the regions Thuin, Philippeville, Dinant, Liege and Luxemburg are endemic for the disease. (figure 3).

Figuur 3 : Verdeling van het aantal gevallen per arrondissement (1996-2002)
Bron : Referentielaboratorium

- What are the symptoms of hantavirus disease (NE) ?

The symptoms occur rather suddenly, about 1 to 4 weeks after contact with the virus.

They can include:

• Fever, up to 40°C
• Chills,
• Headache
• Vomiting and diarrhoea
• Eye pain en blurred vision

- How is the disease diagnosed ?

Diagnosis is based on clinical symptoms and biochemical tests. The diagnosis is confirmed by detection of antibodies to the virus in a blood sample.

- What is the treatment ?

In the majority of the cases, symptomatic treatment of fever and headache is sufficient. Preferably with paracetamol, aspirine and non-steriod anti-inflammatory drugs should be avoided. In some cases more severe renal and/or pulmonary problems can require hospitalisation.

Usually the patient cures within 2 to 3 weeks.

- Who is at risk ?

The disease affects more men than women, children less than 10 years old are rarely affected; most at risk are woodworkers. Persons that were affected by the hantavirus disease, are immune for the virus.

- What are the risk factors ?

The main risk factors for acquiring hantavirus infections are:

1. Direct or indirect contact with rodents :

• Contact with living or dead rodents
• Contact with excreta of rodents

2. Working with wood :

• Manipulation of wood piles
• Intensive woodwork

3. Working around the house :

• Renovation of old houses
• Cleaning of attics, basements, cabins, etc.
• Re-opening places that have been closed for a long time.

Occasional visits to woods (walks, jogging) are not considered to be risk factors.

- What can we do to prevent infection ?

- General measures:

• Wear plastic gloves to remove dead rodents, cleaning up nests or handling traps.
• Apply a bandage on open wounds before performing a risk activity.
• Manipulate rodents, their nests or traps with your back to the wind.
• Avoid deep breathing while performing risk activities.

- Measures at home :

• Store food out of the reach of rodents.
• Avoid the entry of rodents in the home
• If rodents invade the home, immediately put traps or poison in place (in case of poison: be sure to keep children and pets away)
• When opening a place that has been closed for a long time, open doors and windows for at least 30 minutes, while staying outside yourself.
• Clean places that could present a risk with a 10% bleach solution (household bleach). This will inactivate the virus.

Information about Hantavirus

Wetenschappelijk Instituut Volksgezondheid (W.I.V.)
Dienst Epidemiologie en Dienst Virologie
in samenwerking met
het Ministerie van de Vlaamse Gemeenschap
Afdeling Preventieve en Sociale Gezondheidszorg
Team Gezondheidsinspectie
en
het Referentielaboratorium
Militair Hospitaal Koningin Astrid