Lassa fever, likewise known as Lassa Hemorrhagic Fever, is a zoonotic acute viral hemorrhagic disease that leads to severe bleeding. It is caused by a virus called Lassa Virus. Lassa fever is estimated to occur in 400,000 to 500,000 people yearly and about 5000 death every year, according to the CDC.
Lassa fever is endemic in different parts of Africa, involving countries such as Guinea, Liberia, Benin, Ghana, Nigeria, Mali, and Sierra Leone. Other nearby countries can get infected with Lassa virus due to the fact that the animal that carries the virus is a common animal seen in these parts of the world.
How is Lassa fever contacted?
Primary source: Lassa fever is primarily gotten by consumption of foods, water, or use of household items contaminated with Multimammate rat’s urine or feces; the vector that carries the virus.
Secondary source of transmission:
- Direct contact with the blood of a Lassa fever infected person
- Direct contact with secretions from an infected person.
- Direct contact with the urine of a Lassa fever infected person.
Lassa fever symptoms and signs
Lassa fever is asymptomatic in the majority of cases and has a 1% risk of death that usually takes place within two weeks after being infected. In the cases where symptoms appear, It usually occurs within 7 to 21 days after exposure to the virus. Symptoms can be mild in some cases and severe in other cases.
Here are the signs and symptoms of Lassa fever:
- High body temperature (fever)
- Vomiting gastric content
- Muscle pains
- Gastrointestinal bleeding (vomiting blood, blood in stool).
- Extreme Hypotension (dangerously low block pressure) indicating the presence of shock
- Bleeding gums
- Difficulty breathing
- Chest pain
How is Lassa fever diagnosed?
Lassa fever is difficult to diagnose based on symptoms since other hemorrhagic viral infections occur in countries of the world where Lassa fever is mostly seen. Therefore different diagnostic methods are used. Such as:
- Serological investigation: enzyme-linked immunosorbent serologic assays (ELISA) is used to detect immunoglobulin M and immunoglobulin G antibodies of Lassa virus and Lassa antigen
- Polymerase chain reaction (PCR): Detect Lassa virus RNA.
- Viral culture: can be done within 7 – 10days of infection to identify the exact virus
- Full blood count
- Lumbar puncture (Cerebrospinal fluid examination: PCR and Culture): to detect Lassa virus
Treatment of Lassa Fever
- Rehydration therapy (fluids and electrolyte replacements)
- Blood transfusions
- Vasopressors: to elevate blood pressure
- Pain relievers
- Ribavirin is the recommended antiviral medication for Lassa fever.
- Other symptomatic management is carried out according to the symptoms present in the patient.
Prevention of Lassa Fever
- Properly sealing stored foodstuff
- Isolate those infected
- When in contact with a Lassa fever infected person, wear laboratory coats, goggles, masks, gloves, and shoes that can easily be disposed of after used.
- Avoid contact with blood and bodily fluid of an infected person.
- Decrease exposure to rodents
- Use rodent killers in the home regularly
- Have a cat around to hunt rats
- Set rat traps in the house and wear gloves and masks when disposing dead rats in order to avoid having direct contact with the rat.
What are the complications of Lassa fever
For those who survive, the complications of being infected with Lassa virus are:
- Hearing loss
- Miscarriages in 95% of pregnant women
- Swollen baby syndrome in newborns, infants, and toddlers: manifest as bleeding, abdominal enlargement and swelling on feet, hands and face (pitting edema)
Brief History Of Lassa Fever:
- Lassa fever was described in the early fifties (50s), but a case was discovered in 1969 in the town of Lassa in Borno state, Nigeria.
- Lassa fever is named after the city in Borno state, Nigeria, where the first Lassa fever case occurred.