Five years of annual Lassa Fever occurrence

The annual resurgence of Lassa fever in the country should be a major source of worry. The scourge should be treated as an emergency to avoid needless morbidity and mortality in Nigeria. As such, the current upsurge in the cases of Lassa fever demands urgent attention of governments at all levels.

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 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 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 mostly 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, especially in communities with poor sanitation or 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, Ghana, Guinea, Liberia, Mali, Sierra Leone, and Nigeria, but probably exists in other West African countries as well. While Benin, Burkina Faso, Sierra Leone, and Togo experienced outbreaks in 2017, they have since been controlled. Nigeria is still one of several West African countries in which Lassa fever is endemic, with seasonal outbreaks occurring annually between December and June.

As for Nigeria, Lassa fever has become a recurring annual decimal in the nation’s health ‘scene’ in the last half a decade, and in some cases, affected several persons in families across class. 

In 2016, the country reported 273 suspected cases and 149 deaths (case fatality rate 55 per cent) from 23 states. According to Nigeria Centre for Disease Control (NCDC), during the 2017 outbreak, nineteen (19) States (Ogun, Bauchi, Plateau, Ebonyi, Ondo, Edo, Taraba, Nasarawa, Rivers, Kaduna, Gombe, Cross-River, Borno, Kano, Kogi, Enugu, Anambra, Lagos and Kwara) reported at least one confirmed case.
 
As at November 2017, the outbreak was active in five states – Ondo, Edo, Plateau Bauchi and Kaduna. Again, on January 14, 2018, four cases of Lassa fever among health care workers in Ebonyi State were reported at the NCDC. Three of the four cases – two medical doctors and a nurse subsequently passed away, despite efforts to save their lives. According to the University Graduates of Nursing Science Association (UGONSA), more than 40 health workers died as a result of Lassa fever in Ebonyi alone in the past 13 years. As at March, 2018, the NCDC said that Lassa fever had claimed 43 lives in Nigeria with a total of 615 cases reported across 17 states.

In 2019, NCDC Situation Report (SitRep) released on January 20, reveal that from January 1 to 20, 2019, a total of 377 suspected cases of Lassa fever had been reported from nine states. Of these, 136 were confirmed positive and 240 negative; and since the onset of the 2019 outbreak, there have been 31 deaths. As at the time of the SitRep, 81 patients were being managed – Irrua Specialist Teaching Hospital (ISTH) treatment Centre, 30; and Federal Medical Centres in Owo, Bauchi, Plateau, Taraba, and Ebonyi States are managing 25, 9, 8, 3 and 6 respectively. 

Currently, the latest NCDC Sitrep for week 04 (20 – 26 January 2020), shows that since Lassa fever reared its ugly head into the country this season, a total of 318 suspected cases of Lassa fever had been reported from 19 states (Ondo, Edo, Ebonyi, Enugu, Kano, Borno, Nasarawa, Kogi, Rivers, Abia, Adamawa, Benue, Kaduna, Delta, Taraba, Plateau, Bauchi, Osun and Ogun). Of these, 95 were confirmed positive and 223 negative; and since the onset of the 2020 outbreak, there have been 41deaths. Specifically, five Health Care Workers – Kano (3), Taraba (1) and Borno (1) were affected in the reporting week 04. Furthermore, in total for 2020, the 19 affected states have recorded at least one confirmed case across 60 Local Government Areas.

Obviously, Lassa fever is a health deficit in Nigeria that cuts across class, which requires practical and strategic credits to nil the account! Attempts at containing Lassa fever have thrown up different issues just as viral diseases have different strains. Some of the issues range from poor access to preventive care and management, to prohibitive cost of treatment engendering high morbidity and mortality. According to experts, the high cost of managing Lassa fever, as well as, late presentation, slow identification and poor management of cases, range top among reasons for the morbidity and mortality rates recorded over the years.

The treatment of Lassa fever is expensive, as it costs at least N500,000 to treat a patient of Lassa fever with the drug-of-choice, Ribavirin, in a country where the minimum wage is N30,000.  As such, the NCDC should ensure that every state in Nigeria has an emergency stock of Ribavirin and other response commodities available to manage cases to avoid needless loss of lives.

Meanwhile, the Lassa fever national multi-partner, multi-agency Technical Working Group (TWG), known as the National Emergency Operations Centre (EOC), which according to media reports comprises of representatives from the National Emergency Management Agency (NEMA), Federal Ministry of Agriculture and Rural Development, Federal Ministry of Environment, WHO, UNICEF, US Centres for Disease Control, and other relevant partners are working closely with states and the National Primary Health Care Development Agency (NPHCDA).

The TWG continues to coordinate response activities at all levels. As such the current reported cases do not call for panic as early supportive care are already being given to confirmed cases, who are being managed at designated treatment centres. 

Notwithstanding, the affected 19 states Ministries of Health and the Federal Ministry of Health, while responding to contain the current Lassa fever outbreak should not rest on their oars. They should continue to mobilise human and material resources to trace the sources and extent of the disease, follow up on potential contacts, identify early and test suspected cases, since it is a known fact that the annual outbreak occurs between January and June.

So, in addition to the five molecular laboratories for Lassa fever testing in the NCDC network that are working to ensure that all samples are tested and results provided within the shortest turnaround time; Lassa fever endemic states should rise up to the occasion and build comprehensive diagnostic centres, in order to eradicate Lassa fever and other infectious diseases. Again, existing centres such as the Southeast virology centre built by Ebonyi Government four years ago should be made to function maximally.

Strategically, since there is currently no vaccine that protects against Lassa fever, containing Lassa fever lies in prevention. So, while the Federal Government is commended for activating the National EOC; it is important to make the Federal Ministry of Information (FMoI) and National Orientation Agency (NOA) critical parts of the national (EOC) because currently there is no vaccine for Lassa Fever.