Lassa fever killed 101 people in Nigeria over a time span of six months, the Nigeria Center for Disease Control (NCDC) said Saturday.
Cases of the hemorrhagic disease, both confirmed and suspected, stood at 175 with a total of 101 deaths.
The NCDC said as of today, "19 (including Abuja) states are currently following up contacts, or have suspected cases with laboratory results pending or laboratory confirmed cases."
Health authorities say the virus is under control, but there are fears that the actual scale of the outbreak is under-reported.
Large quantities of drugs, including Ribavirin tablets, and bottles of hand sanitizers have been distributed across the country to stop the spread of the deadly virus.
The epidemic was first reported in January, but the first case of the disease occurred in August 2015.
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 neighboring Benin, at least nine people have died of Lassa, with a total of 20 suspected cases, health authorities said February 2.
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.
The disease belongs to the same family as Marburg and Ebola, two deadly viruses that lead to infections with fever, vomiting and, in worse case scenarios, hemorrhagic bleeding.
Its name is from the town of Lassa in northern Nigeria, where it was first identified in 1969. The virus is spread by rats or after coming in direct contact with the bodily fluids of an infected person.