Lassa fever: Treatment, symptoms, advice and help
About Lassa fever
Lassa fever is a serious, contagious viral infection affecting various organs of the body. The condition was first described in the town of Lassa in Nigeria. The viral hemorrhagic fevers are a group of disease caused by several different viruses which cause hemorrhagic manifestations. It is a kind of ‘haemorrhagic fever’ which is transmitted from infected rodents. Lassa fever is an extremely fatal disease with a high mortality rate.
Lassa fever: Incidence, age and sex
Lassa fever is mostly seen in Africa, with epidemic proportions in certain areas of West Africa. It accounts for 15% of adult hospital admissions in West Africa and causes 300,000–500,000 cases annually with approximately 5,000 deaths. It may afflict an individual of any age and gender.
Signs and symptoms of Lassa fever: Diagnosis
The clinical features of Lassa fever have a slow onset and begin with generalised symptoms like fever, chills, exhaustion and muscle ache. Individuals may also complain of gastrointestinal symptoms like nausea, vomiting and abdominal pain. Subsequent involvement of lungs and airways may result in sore throat, cough and chest pain. Sometimes bleeding from tissues may also be manifested in form of maculo-papular rash of skin, nose bleed and bleeding from gums. In most individuals the infection may manifest with minimal and non-specific features.
All viral haemorrhagic fevers have similar non-specific presentations with fever, malaise, body pains, sore throat and headache. On examination, conjunctivitis, throat injection, an erythematous or petechial rash, haemorrhage, lymphadenopathy and bradycardia may be noted. The clue to the diagnosis will come from the travel and exposure history. The causative virus may be isolated, or antigen detected, in laboratories from serum, pharynx, pleural exudates and urine. It is important to exclude other cause of fever, especially malaria, typhoid and respiratory tract infections.
Diagnosis of Lassa fever may require a battery of tests including blood test for deranged liver function and increase in titre of Lassa IgM antibodies. X-ray or CT scan of chest may be helpful if lung involvement is suspected. PCR testing may help in establishing the diagnosis of Lassa fever.
Causes and prevention of Lassa fever
Lassa fever is caused by a virus belonging to the family Arenavirus. This virus is transmitted to humans from urine, saliva and droppings of contaminated rodents. It can also spread from human to human by inhalation or direct contact. This viral infection affects multiple organ system but fortunately spares brain and spinal cord.
Preventive measures like maintaining cleanliness in homes, avoiding rodent dens and avoiding close contact with infected individual may help in keeping this serious infection at bay. Vaccination for Lassa fever is not available at present.Ribavirin has been used as prophylaxis in close contacts in Lassa fever but there are no formal trials of its efficacy.
Lassa fever: Complications
Lassa fever, if not detected and managed timely may lead to permanent hearing loss, convulsions, inflammation of eye tissues and that of covering membrane of heart. The affected individuals may also exhibit markedly low blood pressure.
The mortality rate of Lassa fever usually ranges from 10 to 50 % which is quite significant. Lassa fever in pregnant women may result in serious consequences like abortion in the first trimester.Haemorrhage is also a late feature of established severe disease and may lead to shock. Hepatic and renal failure may occur. Bradycardia and ECG abnormalities are common. Encephalopathy and seizures may develop.
Lassa fever: Treatment
Timely detection and management of Lassa fever is essential to avoid serious and potentially fatal complications. The drug of choice is an antiviral agent named Ribavarin which is administered via intravenous route.- Ribavirin is given intravenously (100mg/kd, then 25mg/kg daily for 3 days and 12.5mg/kg daily for 4 days). Concurrent supportive therapy is also recommended. This includes adequate fluid replacement and maintaining electrolyte imbalance. Other medications like analgesics and antipyretics may also be prescribed for symptomatic relief. General supportive measures are required for dehydration, electrolyte imbalances renal & hepatic failure. Transfusion of blood or blood products may be required.Once haemorrhagic fever is confirmed, isolation is mandatory and good infection control practices will prevent further transmission. The prognosis of Lassa fever may vary from person to person and depend upon the severity of disease.