Nigeria is suffering its worst outbreak of Lassa fever, the World Health Organization (WHO) said yesterday, as local health officials said 72 people had died since the start of this year.

"Nigeria's Lassa fever outbreak has reached record highs, with 317 laboratory confirmed cases," the WHO said in a statement, quoting figures from the Nigeria Centre for Disease Control (NCDC).

Lassa fever, named after the town in northern Nigeria where it was first identified in 1969, is endemic but the number of confirmed cases "has never reached" this level before, it added.

On February 6, 31 people were reported to have died from the disease, which is caused by a virus of the same family as Marburg and Ebola. But in an update, the NCDC said: "Since the onset of the 2018, 325 cases have been classified as: 317 confirmed cases, eight probable cases with 72 deaths." Fourteen health workers have been affected by the virus in six states.

The WHO said a total of 2,845 people who have come into contact with patients have been identified and were being monitored.

Lassa fever is spread through contact with food or items contaminated with rats' urine or faeces or after coming into direct contact with the bodily fluids of an infected person. It can be prevented by enhanced hygiene and avoidance of all contact with rats. More than 100 people were killed in 2016 in an outbreak affecting 14 of the 36 states, including Lagos and the capital Abuja.