A growing Lassa fever outbreak in Nigeria has killed 101 people, as West Africa battles to contain a flare up of the virus, according to data from the nation's health authorities released Saturday.

Nigeria Centre for Disease Control (NCDC) statistics show that reported cases of the haemorrhagic disease -- both confirmed and suspected -- stood at 175 with a total of 101 deaths since August.

"As at today, 19 (including Abuja) states are currently following up contacts, or have suspected cases with laboratory results pending or laboratory confirmed cases," the NCDC said in a statement.

Deaths from the virus were recorded in the nation's political capital, Abuja, Lagos, and 14 other states, the NCDC said.

While health authorities assure Africa's most populous country of more than 170 million they have the virus under control, there are fears the actual scale of the outbreak is under-reported.

The outbreak of Lassa fever was only announced in January -- months after the first case of the disease happened in August -- with subsequent deaths reported in 10 states, including Abuja.

Last year, 12 people died in Nigeria out of 375 infected, while in 2012 there were 1,723 cases and 112 deaths, according to the NCDC.

In neighbouring Benin at least nine people have died in a Lassa outbreak, with a total of 20 suspected cases, health authorities said Tuesday.

Benin was last hit by a Lassa fever outbreak in October 2014, when nine people suspected of having the virus died.

The number of Lassa fever infections in 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.

Lassa fever belongs to the same family as Marburg and Ebola, two deadly viruses that lead to infections with fever, vomiting and, in worse case scenarios, haemorrhagic bleeding.

Its name is from the town of Lassa in northern Nigeria where it was first identified in 1969.

Endemic to the region, Lassa fever is asymptomatic in 80 percent of cases but for others it can cause internal bleeding, especially when diagnosed late.

The virus is spread through contact with food or household items contaminated with rats' urine or faeces or after coming in direct contact with the bodily fluids of an infected person.