Lassa fever is a viral infection caused by the Lassa fever virus. The virus is primarily transmitted to humans via contact with excreta from rats. The disease occurs throughout the year, but more cases are recorded during the dry season.
Lassa fever is spread through:
• Direct contact with urine, faeces, saliva or blood of infected rats.
• Eating food or drinking water contaminated with urine, faeces, saliva or blood of rats.
• Person-to-person through contact with blood, urine, saliva, throat secretion or semen of an infected person.
• Touching of floors, beddings and household materials contaminated with urine, faeces, saliva or blood of rats or an infected person.
• Inhalation of air contaminated with urine, faeces, saliva or blood of rats or an infected person.
Prevention and Control
Presently, there is no vaccine against Lassa fever. To reduce the spread of Lassa fever in the country, the Nigeria Centre for Disease Control (NCDC) advices that standard precautionary measures should be taken by healthcare workers and offers the following advice:
• Maintain a high index of suspicion for Lassa fever.
• All cases of fever must be tested for malaria using appropriate diagnostic tools e.g. rapid diagnostic kit (RDT). If the result is negative and other common causes of fever are ruled out, healthcare workers should suspect Lassa fever.
• Isolate all suspected cases of Lassa fever and contact the appropriate authorities (LGA Disease Surveillance and Notification Officer (DSNO) or State Epidemiologists.
Health care workers are strongly advised to always practice universal standard care precautions when caring for patients, regardless of their presumed diagnosis. Health-care workers seeing a patient suspected to have Lassa fever should immediately arrange for laboratory testing and report to the Local Government disease surveillance and notification officers (DSNOs).
It is important to note the following while caring for Lassa Fever patients:
• Limit the number of health facility staff and visitors in the patient’s room.
• Ensure proper wearing and removal of full personal protective equipment (face masks, hand gloves, gowns, and goggles) before and after entering the patient’s room.
• Wash hands with soap under running water always.
• Limit invasive procedures and use of injectable medications.
• Appropriate disposal and disinfection of items used by Lassa fever patients such as syringes, thermometers, beddings, clothing, cups, plates, spoons, etc.
• Observe safe disposal of injectables and other sharp items.
• The diagnosis of Lassa fever should be suspected in febrile patients returning from areas where Lassa fever is endemic or when common causes of fever such as malaria have been ruled out.
• Samples taken from suspected patients for investigation of Lassa virus infection should be safely handled by trained staff and transported promptly to approved laboratories.
• Observe safe burial practices.
People at risk include:
• People of all age groups who come in contact with the urine, faeces, saliva or blood of infected rats or persons.
• People living in dirty environment. Dirt attracts rats.
• Family members who are taking care of persons infected with Lassa fever.
Health workers, including;
o Doctors, nurses or other health workers providing direct patient care, without universal precautions.
o Hospital staff who clean and disinfect contaminated surfaces, materials and supplies.
o Laboratory staff who handle blood samples from suspected Lassa fever cases.
o Medical or support staff who prepare or handle dead bodies of Lassa fever patients.
Signs and symptoms
Symptoms appear two to 21 days after contact with the Lassa fever virus. The symptoms of the disease usually start with a fever and general body weakness. Other symptoms include: High fever (38.5oC or above), sore throat, vomiting, diarrhea, back pain, cough, chest pain, abdominal pain, restlessness, swelling of the face, bleeding through body openings (nose, ears, eyes, mouth, etc.)
Lassa fever can be treated. Early presentation to a healthcare facility increases the chances of survival.
NCDC toll-free number: 0800-970000-10