Lassa fever

In news: Britain has reported one fatality from Lassa fever. The British health authorities have announced three cases affected with the Lassa virus since 2009. 

Details

Lassa fever is an acute viral haemorrhagic illness caused by Lassa virus, a member of the arenavirus family of viruses, says World Health Organisation (WHO). The virus takes its name from the town of Lassa in northern Nigeria where it was first identified in 1969.

WHO has also confirmed that Lassa fever is known to be endemic in Benin, Ghana, Guinea, Liberia, Mali, Sierra Leone, Togo and Nigeria, but probably exists in other West African countries as well.

The disease is endemic in the rodent population in parts of West Africa, says WHO.

Causes

Matomys rats has the potential to spread the deadly Lassa virus. 

Study has shown that when a Mastomys rat is infected with the virus, it can excrete the virus in its faeces and urine, possibly for the rest of its life.

As a result, the virus can spread easily, especially as the rats breed rapidly and can inhabit human homes.

The most common method of transmission is by consuming or inhaling rat urine or feces. It can also be spread through cuts and open sores.

Having rats for food could also be a possible cause of getting infected with the virus.

Person-to-person contact is possible via blood, tissue, secretions or excretions, but not through touch. Sharing needles may spread the virus, and there are some reports of sexual transmission.

Lassa fever can also be passed between patients and staff at poorly equipped hospitals where sterilization and protective clothing is not standard.

Fatality rate 

Scientific data has confirmed that the overall case-fatality rate is 1%, says WHO.

Among patients who are hospitalized with severe clinical presentation of Lassa fever, case-fatality is estimated at around 15%.