Outbreak status:
- The 2024 Lassa Fever Emergency Operations Center was activated by the Nigerian Center for Disease Control and Prevention in response to the increasing risks of high transmission rates.
- The center reported that 4,726 suspected cases had been monitored, including 766 confirmed cases, and 142 protective cases, for the year 2024.
About the disease:
Lassa fever is an acute viral hemorrhagic disease lasting 2 to 21 days that occurs in West Africa. It was named Lassa after the town of Lassa in Borno State, Nigeria, in 1969. The Lassa virus is part of the Arenavirus family, like the Ebola virus. Rats are the main carriers of this disease, especially the Natal rat (Mastomys natalensis), which is widespread in the Sahara Desert. These mice spread in grain stores, transmitting it to humans.
Mode of transmission:
Humans usually become infected with Lassa virus because of exposure to the urine or feces of infected mice or rats. This virus may also spread to humans through direct contact with the blood, urine, feces, or other body secretions of a person infected with Lassa fever. There is no epidemiological evidence to support the spread of the disease through the air in humans. The infection is transmitted from person to person in the community and healthcare facilities, where the virus may spread through contaminated medical equipment such as reusable needles. Sexual transmission of Lassa virus has been reported.
Lassa fever occurs in all age groups and both sexes. The people most at risk of infection reside in rural areas, especially in communities that suffer from poor sanitation services. Health workers are at risk of contracting Lassa fever if they provide care to infected patients without taking appropriate health prevention measures and following appropriate infection prevention and control practices.
The incubation period: From 2 to 21 days
Symptoms:
Sensitivity to loud noise - high blood pressure - difficulty swallowing - constipation - stomach pain - bloody diarrhea - vomiting blood - nausea - fatigue - headache - shortness of breath - fever - muscle pain - sore throat - seizures - dull hearing.
Diagnosis:
- It is difficult to diagnose the condition based on clinical examination alone, as the symptoms are like other viral infections endemic in West Africa
- Specialized laboratory tests must be used, considering safety procedures when dealing with samples taken from the patient.
- Tests to detect antiviral antibodies and virus identifiers in the blood are used but are considered inaccurate.
- For accurate diagnosis, laboratory culture of the virus is used, a process that takes between a week and ten days.
- PCR testing gives faster and more accurate results, but its high cost limits its use and limits it to conducting scientific research.
Lassa fever treatment:
- Treatment initially focuses on supporting organ functions, such as raising blood pressure, lowering temperature, treating blood salt disorders, and controlling a normal level of oxygen.
- The antiviral drug Ribavirin is used successfully in treating inflammation, especially if its use begins with the onset of symptoms of the disease.
- Studies have shown the ability of this drug to significantly reduce the death rate from 50 percent to about 5 percent.
Prevention
There is no effective vaccine against the virus yet, and the effectiveness of taking ribavirin preventively to stop the spread of the disease in an epidemic manner has not been proven.
The best prevention methods are:
- Getting rid of rodents carrying the virus.
- Storing and preparing food in a healthy manner.
- Purifying and sterilizing drinking water.
- Health workers must also follow safety procedures while handling samples taken from patients to reduce the spread of the virus to them.
- Appropriate clothing must also be worn when mingling with infected patients, such as face masks, gloves, and a uniform that covers the entire body.
Travel restrictions:
WHO does not recommend any restrictions on travel or trade to and from Nigeria based on the information in this report.
References:
World Health Organization (WHO)
Nigeria Centre for Disease Control and Prevention