The virus, which is spread by rodents and claims roughly 5,000 lives a year, is endemic in the region. While the cases are occurring during the Lassa fever season, the World Health Organisation (WHO) is alarmed at the “speed of escalation”. Cases have been recorded in 16 states in Nigeria, where the Nigeria Centre for Disease Control (NCDC) declared an outbreak of Lassa fever on January 22, 2019.
The 213 confirmed cases to date, including 42 deaths, mark a significant increase – already a third of the total cases for all of last year, when Nigeria experienced its worst outbreak of the disease.
Four health workers have been infected so far in the latest outbreak.
Health workers are focusing on early detection and confirmation of suspected cases.
They are also offering supportive care and ensuring infection prevention and control measures in designated health care facilities, with the WHO drafting in teams of experts to offer support.
As well as Nigeria, a total of 12 cases have been confirmed so far in Benin, Guinea, Liberia and Togo, including two deaths, with more suspected cases being investigated.
The WHO is assisting health authorities in these countries with contact tracing as well as providing medical and non-medical supplies and technical and financial resources as required.
Dr Ibrahima Socé Fall, Regional Emergencies Director at WHO Regional Office for Africa said: “We are concerned by the high number of cases so early in the Lassa fever season, which is expected to last another four more months.
“WHO is working with the health authorities in the five-affected countries to ensure health workers have the capacity to detect cases and we are monitoring the regional spread of the disease.”
Dr Socé Fall said the WHO had has also contacted the six other at-risk countries – Burkina Faso, Cameroon, Ghana, Mali, Niger and Sierra Leone – and was supporting prevention and readiness activities as needed.
He added: “WHO continues to advise all countries in the Lassa fever belt to enhance their preparedness and response capacities, especially for early case detection, laboratory confirmation, case management under recommended barrier nursing, risk communication and community engagement.”
Lassa fever is an acute viral haemorrhagic illness which occurs predominantly in West Africa, after human exposure to the urine or faeces of infected Mastomys rats.
Symptoms include fever, headaches and bleeding, and the disease can also result in deafness.
More than 80 percent of Lassa fever cases are rodent-to-human transmission, but human-to-human transmission is also possible.
Prevention of Lassa fever relies on promoting good “community hygiene” to discourage rodents from entering homes by storing grain and other foodstuffs in rodent-proof containers, disposing of garbage far from the home, maintaining clean households, keeping cats and the safe handling of anyone who may have died of the disease.
In health-care settings, health-care workers should always apply standard infection prevention and control precautions when caring for patients.
In total, there are an estimated 400,000 cases annually, although the disease’s mortality rate is only about one percent.