Nigerian authorities have announced increased emergency measures to contain the latest outbreak of Lassa fever in the West African country, following the death of 29 people this month from the viral disease.

"As at 24th of January 2020, 195 confirmed cases and 29 deaths had been reported in 11 states," the Nigeria Centre for Disease Control (NCDC) said in a statement on Saturday.

A national emergency operations centre had been activated to coordinate the response "to the increasing number of Lassa fever cases" across the country.

What is Lassa fever?

Lassa fever is a viral haemorrhagic fever. It belongs to the same family as the Ebola and Marburg viruses, but is much less deadly.

The disease is endemic to the West African country and its name comes from the town of Lassa in northern Nigeria where it was first identified in 1969.

Previously, cases of the disease have been reported in Sierra Leone, Liberia, Togo and Benin - where it killed at least 9 people in 2016.

How is it spread?

The virus is transmitted to humans from contact with food or household items contaminated with rodent faeces or urine. The disease is endemic in the rodent population in parts of West Africa.

The virus, which has an incubation period of between six to 21 days, can also be transmitted through contact with an infected person via biological liquids: blood, urine, saliva, sperm, vomit, faeces.

Symptoms and treatment

Lassa fever is asymptomatic in 80 percent of cases but for others it can cause fever, physical fatigue, nausea, vomiting, diarrhoea, headaches, abdominal pains or sore throat. Neck or facial swelling can sometimes be observed.

According to the World Health Organization (WHO), the antiviral drug ribavirin appears to be an effective treatment for Lassa fever "if given early on in the course of the clinical illness".

Nigeria, Africa's most populous nation with a population of some 200 million, has five laboratories with the capability to diagnose Lassa fever.

Previous outbreaks

The number of Lassa fever infections across West Africa every year is between 100,000 to 300,000, with about 5,000 deaths, according to the US Centers for Disease Control and Prevention (CDC).

Last year, the disease claimed more than 160 lives in Nigeria.

In some areas of Sierra Leone and Liberia, 10 to 16 percent of the people admitted to hospitals annually have Lassa fever, according to CDC, demonstrating the serious impact the disease has on the region.

The number of cases usually climbs in January due to weather conditions during the dry season.