Lassa fever in Nigeria again!

The current outbreak of Lassa fever in the country is a major source of worry as the reports from across the country are scary. The Lagos University Teaching Hospital (LUTH) the other day confirmed that two patients who were at the advanced stage of the infection died despite efforts to save their lives. Furthermore, a resident doctor in the same LUTH exposed to this index case was infected and currently on admission in an isolated ward in the hospital but responding well to treatment. Again, not less than 100 different hospital workers exposed to this index case are currently being monitored. In many states of the federation, there have been reports of more cases. The governments at all level must therefore act fast to curb this menace.

Lassa fever is an acute febrile illness, with bleeding and death in severe cases. According to the World Health Organisation (WHO), it is an acute viral haemorrhagic illness of two to 21 days duration that occurs in West Africa. Descriptions of the disease date from the 1950s, but the virus was first described in 1969 from a case in the town of Lassa, in Borno State, Nigeria. The virus is zoonotic, or animal-borne. Again, WHO states that the reservoir or host of the Lassa virus is the “multimammate rat” called mastomys natalensis, which has many breasts and lives in the bush and around residential areas. So, it is spread by rats!

The virus is shed in the urine and faeces of the rats, hence can be transmitted to humans via direct contact, touching objects or eating food contaminated with these materials or through cuts or sores. Person-to-person infections and laboratory transmission can also occur, particularly in hospitals lacking adequate infection prevention and control measures. Persons at greatest risk are those living in rural areas where mastomys are usually found and especially in communities in cities with poor sanitation as well as crowded living conditions.

About 80 per cent of human infections are without symptoms; the remaining cases have severe multiple organ disease, where the virus affects several organs in the body, such as the liver, spleen and kidneys. According to the WHO, the onset of the disease, when it is symptomatic, is usually gradual, starting with fever, general weakness, muscle and joint pains, prostration and malaise. After a few days, headache, sore throat, muscle pain, chest pain, nausea, vomiting, diarrhoea, cough, and abdominal pain may follow. In severe cases facial swelling, fluid in the lung cavity, bleeding from the mouth, nose, vagina or gastrointestinal tract and low blood pressure may develop. Shock, seizures, tremor, disorientation, and coma may be seen in the later stages.

Lassa fever is known to be endemic in Benin Republic, Ghana, Guinea, Liberia, Mali, Sierra Leone, and Nigeria, but probably exists in other West African countries as well. In 2017, Benin, Burkina Faso, Sierra Leone, and Togo experienced outbreaks that have since been controlled. Although, Nigeria is one of several West African countries in which Lassa fever is endemic, with seasonal outbreaks occurring annually between December and June, the current outbreak of the disease in Nigeria, however, is continuing beyond the normal season. Besides Lagos, active transmission of Lassa fever has been reported in some states (Bauchi, Edo, Ogun, Ondo, Kwara, and Plateau). Altogether, 15 new suspected cases were reported from five states during the last week of July: Plateau (five), Ondo (five) Bauchi (two), Kwara (two) and Ogun (one), including two deaths. In 2016, the country reported 273 suspected cases and 149 deaths (case fatality rate 55 per cent) from 23 states. So, Lassa fever is a significant cause of severe illness and death. This is a sad commentary and all hands must be on deck to redress this situation.

Practically, the reported cases do not call for panic as early supportive care with rehydration and symptomatic treatment improves survival. As such, the Lagos State Ministry of Health and the Federal Ministry of Health should respond to contain the current Lassa fever outbreak by mobilising human and material resources to trace the sources and extent of the disease, follow up on potential contacts, identify early and test suspected cases.

Strategically, since there is currently no vaccine that protects against Lassa fever, containing Lassa fever lies in prevention. Its prevention relies on scientific interventions; and societal and individual behavioural changes hinged on good hygiene. Individuals should adopt preventive practices by storing grain and other foodstuffs in rodent-proof containers, disposing of garbage far from the home and maintaining clean households. Health workers should maintain a high level of alert in the wake of this new outbreak and observe universal precautions in handling all suspected cases of this viral haemorrhagic fever. The scientific intervention requires a connect between town and gown. The Federal Ministry of Health, Centre for Disease Control (CDC) in Nigeria, Nigerian Institute of Medical Research, Institute of Human Virology, Nigerian research and development units of health-related organisations such as pharmaceutical companies and universities should collaborate and engage in a well-coordinated manner to search for solutions through research on the specie of rat that hosts the Lassa virus and how to make them de-zoonotic in order to render them impotent as carriers. They should also lead a vaccine and treatment research. In addition, any institution or individual who has done any useful research should make it public. Also, the relevant ministries, departments and agencies of government at all levels should map the pattern of the outbreak with a view to preventing or dealing with future occurrences.