Nigeria reports a steady decline in the number of confirmed Lassa fever cases
Through the 10th week of 2018, Nigerian health officials have reported a total of 1386 suspected cases reported across 19 affected states, of which 365 were laboratory confirmed.
In addition, 90 deaths (81 lab confirmed) have been reported.
The Nigeria Centre for Disease Control (NCDC) says there has been a steady decline in the number of confirmed cases reported in the last three weeks.
Historically, a steady decline in the number of cases reported is an indication of a gradual exit from the peak period of the disease.
The decline in the number of new cases can be linked to the enhanced response activities in the last few weeks. However, it is important to note that additional efforts need to be place on actively searching for cases and ensuring they are all tested for Lassa fever.
This has necessitated the deployment of active case teams to the three-hotspot states of Edo, Ondo and Ebonyi State to support active case search and contact tracing activities in these states. The expected outcomes of these activities is to
- Identify and list all contacts of confirmed Lassa fever patients
- Monitor all listed contacts for 21 days
- Refer all symptomatic contacts for Lassa fever testing
- Follow up all symptomatic cases who become positive and refer immediately to designated treatment centres.
- Active search in communities for suspected cases and ensure lab investigations are carried out for them.
According to the US Centers for Disease Control and Prevention (CDC), Lassa fever is an acute viral illness that occurs in West Africa. The virus, a member of the virus family Arenaviridae, is a single-stranded RNA virus and is zoonotic, or animal-borne.
Lassa fever is a significant cause of morbidity and mortality. While Lassa fever is mild or has no observable symptoms in about 80% of people infected with the virus, the remaining 20% have a severe multisystem disease.
The animal host of Lassa virus is a rodent known as the “multimammate rat” of the genus Mastomys. Humans get infected with Lassa through aerosol or direct contact with excreta from the rodent. Laboratory infections do occur primarily through contaminated needles.
The symptoms of Lassa fever typically occur 1-3 weeks after the patient comes into contact with the virus. These include fever, retrosternal pain (pain behind the chest wall), sore throat, back pain, cough, abdominal pain, vomiting, diarrhea, conjunctivitis, facial swelling, proteinuria (protein in the urine), and mucosal bleeding. Neurological problems have also been described, including hearing loss, tremors, and encephalitis.