Lassa fever (a medical condition caused by rodents and mainly occurs in West Africa) is an acute viral haemorrhagic illness that lasts for two to twenty one days; it is transmitted to humans through foods or any household item or office object that is contaminated with the urine or faeces of rodents.
This contagious disease affects many West African countries like Nigeria, Ghana, Benin republic, Guinea, Liberia, Mali and Sierra Leone; when adequate prevention and control measures are lacking, this disease can spread from person to person, even among hospital staffs and 15% of severe cases of Lassa fever are fatal.
Infected rodents are the reservoir or host of the Lassa virus; rats that are infected with this virus do not become ill but they excrete the virus in their urine and faeces. Humans become infected with this virus when they are exposed to or come in contact with the urine or faeces of infected rats.
Another ways the virus spreads is when healthy humans come in contact with the bodily secretions or fluids of someone infected with Lassa fever; so coming in direct contact with the blood, faeces, urine, sweat and other body fluid of an infected person can spread Lassa fever.
Other ways the virus can spread are through the use of contaminated medical equipment like re-used needles; it can also be spread through sex and there is no evidence that is airborne. This disease occurs in all age groups including new born babies and in both sexes.
Risk factors for Lassa fever are living in places where rats are found, living in a crowded area, living in a place with poor sanitation, working as a health practitioner in a hospital or medical laboratory where there are no proper prevention and control practices or measures.
80% of people infected with Lassa virus do not show symptoms and the clinical course of this disease is so variable, its detection in infected patient has been difficult but when the disease has been confirmed in an individual or a community, prompt isolation of the affected individuals is done to prevent spread of the disease.
Good prevention and control practices of infection are put in place to prevent healthy people from getting the disease and rigorous contact tracing is done to quarantine suspected individuals and to stop outbreaks.
Symptoms of Lassa fever
When Lassa virus enters the human body through things contaminated with the urine or faeces of an infected rodent; it takes six to twenty one days for the virus to incubate in the body.
After the incubation, mild symptoms like general weakness, fever and malaise begin to appear; after a few days other symptoms like headache, sore throat, muscle pain, chest pain, vomiting, nausea, cough, diarrhea and abdominal pain follow and in severe cases of Lassa fever, facial swelling, low blood pressure, bleeding from the mouth, nose, vagina and gastrointestinal tract and fluid in the cavity of the lungs develops.
In the later stage of this disease, there is presence of protein in the urine of the infected patient; followed by shock, seizures, tremor, disorientation and coma. 25% of patients who survive this disease turn deaf; but in half of these cases their hearing returns partially after one to three months. During the process of recovery, patients may experience hair loss and gait disturbance.
In fatal cases of Lassa fever, death usually occurs within 14 days; this disease is severe in pregnant women, especially in late pregnancy; it can lead to loss of the mother or baby; fetal loss or maternal death occurs in more than 80% of cases during the third trimester.
Lassa fever is difficult to diagnose because its symptoms are non-specific and varies from individual to individual especially in the early course of the disease; it is difficult to distinguish Lassa fever from other viral haemorrhagic disease like Ebola and other disease that cause fever like typhoid fever, yellow fever, malaria and shigellosis.
Due to the above reasons, Lassa fever infection can only be defined definitively in the laboratory using the following biochemical tests:
- Reverse transcriptase polymerase chain reaction (RT-PCR) assay
- Anti-body enzyme linked immunosorbent assay (ELISA)
- Antigen detection tests
- Virus isolation by cell culture (Microbiology)
Whenever the above signs are noticed or any sign of fever noticed and there have been a confirmed case of Lassa fever in your environment; it is advisable to go for medical checkup so that the doctor can know exactly what is wrong with you.
It will be also be nice on your part to tell the doctor if you are suspecting Lassa fever so that the doctor and any other health worker attending to you can protect themselves and prevent spreading it to their family members.
To treat Lassa fever, an anti-viral drug RIBAVIRIN is given to patients and it is very effective especially if the case was diagnosed early and treatment commenced immediately.
Prevention of Lassa fever
Rodents are the carriers of the Lassa virus and without eliminating them from the environment or home, prevention of this deadly disease will be difficult. This can be done through:
- Practicing good community hygiene: Keeping the environment very clean will prevent rodents from feeling welcomed and entering the homes.
- Grains, farm produce, foodstuffs, food preserved in cans or containers should be stored properly in a rodent free environment or rodent proof containers so that the rodents will not eat the food, urinate or defecate on them.
- Garbage and sewage should be far from the home if not these rodents will feel welcomed because they like dirty environments.
- Keep cats, they will help to chase rodents from your house and environment. Cats and rats are enemies and anywhere a cat is found, rats avoid that place so that they won’t be killed.
- Family members should be careful not to come in contact with the bodily fluids when caring for a sick person and the sick person should be taken to the hospital for proper and effective treatment.
- Health workers should employ standard prevention and control measures when handling viral infections like Lassa fever; extra precautions should be taken to avoid contact with patients’ bodily fluids like blood and urine.
- Health workers irrespective of the patient presumed diagnosis should always be on protective wears (a clean non-sterile long sleeve gown), hand gloves, medical face masks, face shield, goggles and employ other means of protection like basic hand hygiene and respiratory hygiene.
- Health workers and hospitals should practice safe injection practices and safe burial practices.
- Samples taken from infected patients should only be handled by well-trained medical laboratory scientists; the diagnosis should be carried out in well-equipped and standard laboratory that offers maximum biological containment conditions.
- Importation of food and other household items from Lassa fever communities should stop till the case is arrested.
- All bush meats especially those of rodents should be avoided.
- All foods and water should be properly covered.
- If you suspect a rat has eaten a particular food, you should discard it.