Nigeria's Centre For Disease Control says there have been more than 250 cases of Lassa fever, which belongs to the same family as the Ebola and Marburg viruses but is far less deadly.

Around 170 died during an outbreak last year.

Lassa is spread by contact with rat faeces or urine and is endemic in Nigeria.

At the weekend the authorities said they had activated a national emergency operations centre to co-ordinate the response to the increasing number of cases across the country.

Multimammate rodents spread Lassa virus via their urine and droppings