Lassa fever reported in Germany

German health authorities have reported to WHO an imported case of Lassa fever, confirmed by laboratory tests at the Bernhard-Nocht-Institute of Tropical Medicine, Hamburg, Germany.

The patient, resident in Sierra Leone, became ill with fever on 5 July 2006 and flew to Germany on 10 July 2006, where he arrived the following day.

He is currently being treated in isolation in Frankfurt and German health authorities have taken the appropriate measures to prevent further transmission of the virus.

Although the risk of transmission of Lassa virus to co-passengers is extremely low, an international contact tracing exercise, coordinated by the Robert Koch Institut, Berlin, Germany, is ongoing. The relevant flights are:

• 10 July 2006; SN Brussels Airlines; flight SN 207; from Freetown-Sierra Leone, via Abidjan,Cote d’Ivoire, to Brussels,Belgium;
• 11 July 2006; SN Brussels Airlines; flight SN 2607; from Brussels,Belgium to Frankfurt, Germany.

What is lassa fever?

Lassa fever is an acute viral illness caused by Lassa virus. The disease is endemic in west African countries of Guinea, Liberia, Sierra Leone and Nigeria. The virus reservoir is the wild rodent in west Africa. When humans get infected, the consequences range widely in severity, from asymptomatic infection without illness to extremely severe illness which may have a fatal outcome.

Incubation period is 6 to 21 days. The patient usually presents with fever, malaise, headache, sore throat, cough, nausea, vomiting, diarrhoea, myalgia, chest and abdominal pain. Inflammation of the throat with white tonsillar patches is an important distinguishing feature. The death rate is about 15%.

How does it spread?

Disease transmission is primarily through aerosol or direct contact with the excreta of infected rodents. Person-to-person spread may occur during the acute phase of fever.

How can you prevent it?

There is no vaccine available for Lassa fever. Travellers to endemic areas have to observe good personal hygiene to minimize the risk of contracting Lassa fever and adopt the following precautions:-

• avoid visiting or sleeping in places of poor environmental hygiene.
• do not have contact with sick rodents.
• do not contact person with fever.
• on return, if fevers of unknown origin develop, one should seek prompt medical advice, informing doctor the recent ravel history to Lassa fever endemic areas so as to facilitate diagnosis.

How is it treated?

Specific treatment with intravenous injection of anti-viral drug may be effective if given within the first six days of illness.