A new viral disease in Africa: Here’s everything we know about Lassa fever

The U.K. Health Security Agency (UKHSA) has reported three cases of Lassa fever in the past week. An acute viral illness, the disease has claimed one life so far, that of a newborn baby. Here's all you need to know about this disease. 

The origins

According to the U.S. Center for Disease Control and Prevention (CDC) website, Lassa fever is a disease of animal origin that is endemic to Western African countries such as Sierra Leone, Liberia, Guinea, and Nigeria. The disease is caused by the Lassa virus, named after the town in Nigeria, where it was first reported in 1969. 

The virus is spread around by the multimammate rat, Mastomys natalensis, more commonly known as the African rat. True to its name, the African rat is found quite commonly in other parts of Africa as well where it can spread the virus further. The CDC website states that neighbors of West African states are at most risk of seeing infections due to the Lassa virus.

Once host to the Lassa virus, the African rat sheds the virus in its urine and droppings for extended periods of time. It is suggested that this could mean for its entire life too. Since rats like to infest areas near human settlements, they can transfer the virus to humans by contaminating food or even direct contact.

Humans can get the Lassa virus by inhalation of the virus particles or ingestion of food contaminated by the virus. Once one is infected, the virus can be further transferred to another human through an exchange of bodily fluids such as saliva or by coming in contact with infected blood, tissue, or human excreta as well. 

 In the case of U.K. patients, they had a history of travel to Western Africa recently. 

The symptoms

Symptoms of Lassa fever can be seen as early as one week but even as late as up to three weeks after exposure. For most individuals, the symptoms are mild such as mild fever, fatigue, and headache.

About 20 percent of the infections see respiratory distress, repeated vomiting, swelling on the face, pain in the chest and back as well as hemorrhaging, internal or external bleeding from the eyes, nose, or gums. 

Up to 20 percent of those infected need hospitalization due to the illness, but as many as third report deafness of various degrees following the infection. In many cases, the hearing loss is permanent. Statistically, only one percent of those infected with the virus die but pregnant women in their third trimester are at high risk since the infection can lead to spontaneous abortion with a 95 percent mortality of fetuses, CDC states on its website. 

Another pandemic potential?

Luckily, the disease does not spread as rapidly as the coronavirus, which we are still hoping to recover from. While a person-to-person transmission is possible, it also requires an exchange of body fluids, which usually does not occur in normal circumstances. 

In the case of the ill-fated family in the U.K., the newborn child succumbed to the disease but contract tracing efforts haven't shown that the infection has spread further yet. The staff at the hospitals where the family was being treated have been asked to undergo precautionary isolation for two weeks, The Guardian reported. 

According to a UKHSA statement, the U.K. has seen eight cases of the Lassa virus so far since the 1980s, with the last two occurring as far back as 2009. The overall risk to the public is very low.