Prevention is the only bet for avoiding the onset of Lassa fever

New Delhi, 19 July 2018: Earlier this year, Nigeria fell under the grip of a viral infection called the Lassa fever. Many people succumbed to the symptoms and died. This fever comes under the list of priority diseases enlisted by the World Health Organization (WHO). Apart from Nigeria, the Lassa virus is endemic in Benin, Ghana, Guinea, Liberia, Mali, Sierra Leone, and other countries in West Africa.

Lassa fever is an acute viral hemorrhagic illness caused by Lassa virus, a member of the Arenavirus family of viruses. It is a zoonotic disease. Rodents (multimammate rats) are the animal reservoirs and shed the virus in their urine and feces.

Speaking about this, Padma Shri Awardee, Dr K K Aggarwal, President, HCFI, said, “Humans acquire the infection from contact with infected rodents through rodent urine or feces, inhalation of aerosolized rodent excretions, or consumption of infected rodents as a food source. Person-to-person transmission can occur through direct contact with infectious body fluids (e. g., blood, urine, pharyngeal secretions, vomitus, or other body secretions), unprotected contact with potentially infectious material (e.g., touching vomitus) and mucosal exposure from splashes of body fluids. People with Lassa infection are not believed to be contagious prior to symptom onset. The incubation period of this fever is about 10 days (range 6-21 days).”

Initially, the symptoms are mild and include low-grade fever, general weakness, and malaise. This is followed by headache, sore throat, muscle pain, chest pain, nausea, vomiting, diarrhea, cough, and abdominal pain. In severe disease, facial swelling, fluid in the lung cavity, bleeding from the mouth, nose, vagina or gastrointestinal tract and low blood pressure are present. Later stage may be characterized by shock, seizures, tremor, disorientation and coma.

Adding further, Dr Aggarwal, who is also the Group Editor of IJCP, said, “The overall case-fatality rate is 1%, while in hospitalized patients, the case-fatality rate is 15%. The diagnosis of this condition is usually supported by a relevant history of exposure along with suggestive signs and symptoms. It is possible to improve survival rates through early supportive care with rehydration and symptomatic treatment. However, there is currently no vaccine for this condition.”

Indian doctors need to update their knowledge in view of a large number of Nigerian patients coming to India for treatment.

Some tips from HCFI

• Avoiding rodents (multimammate rats).
• Consider all patients as infectious even if signs and symptoms are mild.
• All standard, contact, and droplet precautions as well as correct use of appropriate personal protective equipment should be strictly adhered to.
• Blood and body fluid specimens from patients with suspected Lassa fever infection should be considered highly infectious. Caution should be exercised when handling such material.
• Postexposure prophylaxis with oral ribavirin for contacts with known or suspected Lassa fever infection with risk factors for transmission such as penetrating needle stick injury, exposure of mucous membranes or broken skin to blood or body fluids, and participation in procedures involving exposure to bodily fluids or respiratory secretions without use of personal protective equipment.