Even before the Corona Virus broke out, something equally deadly was already in the air here in Nigeria. It has taken lots of lives and is still taking more if not properly managed. It is called Lassa Fever.
What is Lassa Fever?
Lassa fever is a major public health challenge in West Africa, with Nigeria bearing the highest burden. It is an Acute Viral Haemorrhagic Fever (VHF) caused by the Lassa virus. The natural reservoir for the virus is the Mastomys Natalensis rodent (commonly known as the multi-mammate rat). Other rodents that carry the virus have also been identified.
Epidemiological data show that Lassa fever occurs throughout the year, but more cases are recorded during the dry season i.e. November through May.
Descriptions of the disease date from the 1950s. The virus was first described in 1969 from a case in the town of Lassa, in Borno State, Nigeria. Lassa fever is relatively common in West Africa including the countries of Nigeria, Liberia, Sierra Leone, Guinea, and Ghana. There are about 300,000 to 500,000 cases which result in 5,000 deaths a year.
An outbreak of Lassa fever occurred in Nigeria during 2018 and spread to 18 of the country’s states; it was the largest outbreak of Lassa recorded. As of February 25, 2018, there were 1081 suspected cases and 90 reported deaths; 317 of the cases and 72 deaths were confirmed as Lassa-induced deaths.
What are the symptoms of Lassa Fever?
The early stages of Lassa fever present initially like other febrile illness such as malaria. Symptoms of the disease generally include fever, headache, sore throat, general body weakness, cough, nausea, vomiting, diarrhoea, muscle pains, chest pain, and in severe cases; unexplainable bleeding from ears, eyes, nose, mouth, vagina, anus and other body orifices. It could also present as persistent bleeding from sites of intravenous cannulation.
The incubation period (time between an infection and appearance of symptoms of the disease) is 3 to 21 days. Early diagnosis and treatment increase the chances of survival.
How is it spread?
1. Direct contact with urine, faeces, saliva or blood of infected rodents.
2. Ingesting food and drinks contaminated with urine, faeces, saliva or blood of infected rats.
3. Contact with objects, household items or surfaces contaminated with urine, faeces, saliva or blood of infected rats.
4. Person-to-person transmission can also occur through contact with blood, urine, faeces, vomit and other body fluids of an infected person, particularly in a hospital environment where infection prevention and control practices are not optimal.
Prevention and Treatment:
Control of the Mastomys rodent population is impractical, so measures focus on keeping rodents out of homes and food supplies, encouraging effective personal hygiene, storing grain and other foodstuffs in rodent-proof containers, and disposing of garbage far from the home to help sustain clean households. Gloves, masks, laboratory coats, and goggles are advised while in contact with an infected person, to avoid contact with blood and body fluids. These issues in many countries are monitored by a department of public health. In less developed countries, these types of organizations may not have the necessary means to effectively control outbreaks.
There is also no vaccine for humans to treat Lassa Fever as of 2019. Researchers at the United States Army Medical Research Institute of Infectious Diseases facility had a promising vaccine candidate in 2002. They have developed a replication-competent vaccine against Lassa virus based on recombinant vesicular stomatitis virus vectors expressing the Lassa virus glycoprotein. After a single intramuscular injection, tested primates have survived lethal challenge, while showing no clinical symptoms.
Treatment is directed at addressing dehydration and improving symptoms. All persons suspected of Lassa fever infection should be admitted to isolation facilities and their body fluids and excreta properly disposed of.
For medications, the antiviral medication ribavirin has been recommended, but evidence to support its use is weak. Some evidence has found that it may worsen outcomes in certain cases. Fluid replacement, blood transfusions, and medication for low blood pressure may be required. Intravenous interferon therapy has also been used.
The national guidelines for Lassa fever case management and Infection prevention and control are available on the NCDC website for download (http://ncdc.gov.ng/diseases/guidelines).
Please report all suspected cases of Lassa fever to your Local Government Area Disease Surveillance and Notification Officer (DSNO). They are the first link to response and care for Lassa fever cases in Nigeria.