Causes and risk factors
Lassa fever is caused by Lassa virus. The virus is transmitted to humans from a rodent known as the “multimammate rat.” Mode of transmission includes – coming in contact with the objects contaminated by the urine or droppings of the rodent, eating contaminated food, cuts or open wounds coming in direct contact with rodent excretions, inhaling tiny particles in the air contaminated with rodent excretions. Person to person infection occurs when a healthy person comes in contact with the blood, tissue, secretions, or excretions of an infected person. Contaminated medical equipment can spread the disease. Sexual transmission of Lassa fever is possible.
Clinical presentation
Patient with Lassa fever presents with fever, weakness, and malaise. This is followed by sore throat, cough. Patient complains of retrosternal pain, back pain, abdominal pain. There can occur hearing loss. Gastrointestinal complaints such as vomiting, diarrhea, and constipation can be observed. Conjunctivitis can occur. There may be facial swelling. There may be fluid in lung cavity. Mucosal bleeding takes place. There can be hypertension or hypotension. Pericarditis may occur. Tremors, encephalitis, meningitis, seizure occurs in severe cases.
Investigations
Medical history by the patient and clinical examination by the doctor helps in diagnosis. ELISA test for antigen and IgM antibodies is required. Complete blood count to check white blood cells and platelet count is recommended. RT-PCR is done. Virus isolation by cell culture is required. Imaging studies such as CT scan, MRI may be useful for further evaluation in severe cases.
Treatment
Lassa fever is treated with antiviral drug. Pregnant women who are infected in third trimester require induced delivery to have better chance of survival. Symptomatic treatment with anti-pyretic, analgesics, anti-hemorrhagic medicines is given.
Complications
Complications such as deafness, spontaneous abortion, meningitis, encephalitis, anemia may occur.
When to Contact a Doctor
One must consult a doctor if the patient is having symptoms of viral fever, bleeding tendency.
Prevention
Proper storage of food, keeping home clean to discourage rodent dwelling, covering the food, avoiding contact with infected persons can prevent the disease.
Facts and figures
The overall mortality rate of Lassa fever is 1%. The death rate is high for pregnant women in third trimester; 95% of fetuses die in uterus of the infected pregnant woman.
Systems involved
Circulatory system, central nervous system, GI system, respiratory system.
Organs involved
Heart, brain, ear, eyes, throat, GI tract
WHO statistics
Mortality rate of Lassa fever is 1%. It is seen more in West Africa.
