Date Published: 11 February 2016
Lassa Fever outbreak in Benin
An emergency response is underway to deal with an outbreak of Lassa fever in the West African country of Benin. In addition to treating people who have the disease, efforts are being made to prevent further spread of the disease.
What is Lassa fever ?
Lassa fever is an acute viral haemorrhagic illness caused by the Lassa virus and transmitted via contact with food or household items contaminated with the faeces of infected rodents, usually rats. It can also be transmitted from person-to-person via bodily fluids such as blood, urine, saliva, or sperm and in laboratories that lack adequate infection control procedures. The Lassa virus, which was not identified until 1969, is a single-stranded RNA virus belonging to the virus family Arenaviridae.
It has been estimated that about 80% of people who have been infected with the Lassa virus have no symptoms. However, around 20% of people infected with the virus go on to experience severe effects, possibly affecting multiple organs such as the liver, spleen and kidneys. In those cases the disease has been described as following a 'complicated course'2 because the clinical progress of Lassa fever is extremely variable.
When Lassa fever does develop it tends to manifest gradually beginning with fever and general weakness. After a few days further effects such as a headache, sore throat, muscle pain, chest pain, nausea, vomiting, diarrhoea, cough, and abdominal pain may follow. More severe symptoms are not unknown - facial swelling, fluid in the lung cavity, bleeding from the mouth, nose, vagina or gastrointestinal tract and low blood pressure have all been recorded. Deafness has also been observed in about 25% of survivors, although in many cases at least partial hearing returned after some months. Sadly, this disease is especially severe late in pregnancy, when maternal death and/or loss of fetus have been recorded in more than 80% of cases during the third trimester.
How many people have been affected ?
The authorities in Benin (officially the 'Republic of Benin') have been monitoring the situation and reviewing the possible need to take action since a pregnant woman with symptoms of the disease died in early January 2016 and six health workers in the same hospital in central Benin showed similar symptoms.
In the last week or so more cases were tested by the Nigerian reference laboratory, of which three were confirmed having Lassa fever. Since this outbreak in Benin, there have been a total of four confirmed cases to date (10th Feb) and 52 suspected cases. Of these people, 17 have died including two health workers. One of the confirmed cases is a 4-month-old child who is currently being treated in Tchaourou, in the north-east of Benin.
What is being done in response to this outbreak of Lassa Fever ?
The government is receiving assistance from international organizations including WHO and UNICEF. The measures taken so far in response to the outbreak, include:
- Setting up quarantine units to isolate and treat people infected with the Lassa virus.
- Establishing a contact tracing system to try to locate and communicate with other people who might have been exposed to Lassa fever.
- Arranging for a network of almost 200 community health workers located across the Benin to monitor the contacts i.e. the people who might have been exposed to the disease.
- Making the anti-viral drug Ribavirin available in the city of Cotonou and also in the affected areas. (Widely considered to be effective against Lassa fever, Ribavirin is on the World Health Organization's List of Essential Medicine2 a list of medication considered essentialn in a basic health system).
- Distributing personal protection equipment (PPE) for health care workers, including tarpaulins, gloves, boots, goggles and masks, decontamination products,infrared thermometers, water treatment units and medical and laboratory supplies.
- Training health care workers about use of the equipment, medical protocol, and in the identification of and active search for contacts;
- Launching a public awareness campaign with messages broadcast by local radio, television, and through online media.
- Implementing a national awareness campaign through which everyone is being urged to seek treatment immediately if any symptoms appear. People also being provided with important information about how to prevent infection, such as by washing hands with soap and water and limiting contact with people who are showing symptoms of the disease.
The Republic of Benin was last affected by Lassa Fever over a 4 month-period during 2014-2015 when 16 cases were reported and 9 people died3. Since it was first described during the 1950s this disease is also thought to have occurred in Guinea, Liberia, Sierra Leone, Nigeria and possibly other West African countries4, although it might not have been active or reported in some locations for a considerable time.