The world is still scrambling to contain the rapid spread of Covid-19. However, for Nigeria, the largest West African nation, it is more than the coronavirus. From January 1st to the 9th of February 2020, there were 472 laboratory confirmations of the Lassa fever virus across 26 of the 36 states in the country. Also, the death toll has risen to 103. This translates to a case fatality rate (CFR) of 17.6%. Interestingly, this is lower than the 21.1% recorded within the same period in 2019. The worst-hit states are Edo and Ondo with 167 and 156 cases respectively.
The primary route of transmission of the virus is through contact with items contaminated with the feces or urine of multimammate rat (Mastomys natalensis). However, secondary infection can occur through direct contact with blood, secretions, and other body fluids of infected persons.
Lassa fever is a zoonotic, acute viral illness. It is endemic in parts of West Africa including Sierra Leone, Nigeria, Benin, Ghana, Liberia, and Guinea. However, the virus may exist in other West African countries. Breaking the cycle of transmission is crucial during disease outbreaks. Following the discovery of Lassa fever in Lagos State, the State Commissioner of Health, Prof. Akin Abayomi said,
“We have identified 63 of the persons he may have been in contact with since his arrival from Ebonyi State into Lagos Law School, the Nigeria Air force clinic, Onikan and LUTH. They are been monitored; If they develop any symptom of Lassa fever, we will pick them up early and isolate them so that we can break the circle of transmission.”
Signs and Symptoms and Survival
The symptoms of Lassa fever are nonspecific. In fact, in the majority of the infections (approx. 80%), symptoms are mild. Mild symptoms can include malaise, slight fever, and general weakness. In 20% with a severe case of the virus, symptoms include bleeding (from the eyes, nose), chest pain, recurring vomiting, respiratory distress, and shock. Symptoms usually occur 1 to 3 weeks after contact with the virus.
In severe cases, death may occur in two weeks due to multiple organ failure. However, the most common complication of Lassa fever is deafness. It is important to note that deafness may occur in both mild and severe cases. Fatality for women in their third trimester of pregnancy is as high as 95%.
An antiviral drug, Ribavirin, has been used with success in the treatment of Lassa fever. However, it is more effective if given in the early stages of the illness. In addition to Ribavirin, supportive care also helps to increase the survival rate. Supportive care usually consists of maintaining fluid and electrolyte balance, oxygenation, and treatment of any other complicating infections.
How to Permanently Deal with Recurring Outbreaks
A popular quote says ‘prevention is better than cure’. The primary route of Lassa fever virus transmission to humans is from the Mastomys rodents. Therefore, avoiding contact with rodents will ultimately lower the chances of infection. In Nigeria, the annual peak of human cases is during the dry season (December to April). This is not surprising since it follows the reproduction cycle of the Mastomys rodents (May to June).
Putting food in rodent-proof containers is also recommended. Also, general hygiene like keeping the house clean will keep the rodents at bay. The use of traps around the house can significantly lower the rodent population—and the risk of infection.
As part of an effort to fight reoccurring Lassa fever outbreaks, the Minister of Environment, Dr. Mohammed Abubakar Mahmud has launched a campaign against rats in homes. The campaign is tagged ‘National Environmental Response Campaign to Eradicate Lassa Fever’. Launching the campaign at Rigasa community in Kaduna the minister said,
“Today marks the beginning of a robust plan focusing on primary prevention through sound environmental sanitation. This and other interventions are aimed at preventing, in addition to Lassa fever, an array of environmental sanitation-related diseases like cholera, malaria, typhoid, and hepatitis. Our communities, unfortunately, are fertile breeding grounds for rodents due to poor environmental sanitation which ensures sustained sources of food for rodents.”
The total elimination of Mastomys rodents may be an unrealistic goal. This is because of its wide distribution in Africa. Therefore, a more realistic goal should aim at reducing their populations in homes. Also, the use of rodents as food should be strongly discouraged.