Lassa Fever!!! Awareness and Prevention

Lassa fever is an acute viral illness that occurs in West Africa. The illness was discovered in 1969 when two missionary nurses died in Nigeria. The virus is named after the town in Borno, Nigeria where the first cases occurred.

About 80% of people who become infected with Lassa virus have no symptoms. One in five infections results in severe disease, where the virus affects several organs such as the liver, spleen and kidneys.

TRANSMISSION

• Humans usually become infected with Lassa virus from exposure to urine or faeces of infected Mastomys rats.
• Lassa virus may also be spread between humans through direct contact with the blood, urine, faeces, or other bodily secretions of a person infected with Lassa fever.
• There is no epidemiological evidence supporting airborne spread between humans.
• Person-to-person transmission occurs in both community and health-care settings, where the virus may be spread by contaminated medical equipment, such as re-used needles.
• Sexual transmission of Lassa virus has been reported.
• Lassa fever occurs in all age groups and both sexes.
• Persons at greatest risk are those living in rural areas where Mastomys are usually found, especially in communities with poor sanitation or crowded living conditions.
• Health workers are at risk if caring for Lassa fever patients in the absence of proper barrier nursing and infection control practices.

SYMPTOMS OF LASSA FEVER

• The incubation period of Lassa fever ranges from 6-21 days.
• The onset of the disease, when it is symptomatic, is usually gradual, starting with fever, general weakness, and malaise.
• After a few days, headache, sore throat, muscle pain, chest pain, nausea, vomiting, diarrhoea, cough, and abdominal pain may follow.
• In severe cases facial swelling, fluid in the lung cavity, bleeding from the mouth, nose, vagina or gastrointestinal tract and low blood pressure may develop.
• Protein may be noted in the urine.
• Shock, seizures, tremor, disorientation, and coma may be seen in the later stages.
• Deafness occurs in 25% of patients who survive the disease.
• In half of these cases, hearing returns partially after 1-3 months.
• Transient hair loss and gait disturbance may occur during recovery.
• Death usually occurs within 14 days of onset in fatal cases.
• The disease is especially severe late in pregnancy, with maternal death and/or fatal loss occurring in greater than 80% of cases during the third trimester.

PREVENTION AND CONTROL

Prevention of Lassa fever relies on promoting good "community hygiene" to discourage rodents from entering homes.

Effective measures include storing grain and other foodstuffs in rodent-proof containers, disposing of garbage far from the home, maintaining clean households and keeping cats. Because Mastomys are so abundant in endemic areas, it is not possible to completely eliminate them from the environment. Family members should always be careful to avoid contact with blood and body fluids while caring for sick persons.

Apple lovers should wash them with salt and warm water before refrigerating them to eat. Everyone should avoid testing of dry garri by chewing them for starch in the market. All garri drinkers should not take garri for now.

Our garri sellers in the market buy their garri from bush markets. These garri are often fried half dry and are subsequently dried on polythene sheets on the tarred roads or compounds in the villages. These rat dive in at will, to feed their hungry bellies and in the process defecate and urinate on the garri, which dry up with it. If used for Eba, the virus may die because of the hot water used. But if soaked, the virus is directly ushered in. Please no one should joke with this precaution, except you process your cassava yourself.

In health-care settings, staff should always apply standard infection prevention and control precautions when caring for patients, regardless of their presumed diagnosis. These include basic hand hygiene, respiratory hygiene, use of personal protective equipment (to block splashes or other contact with infected materials), safe injection practices and safe burial practices.

Health workers caring for patients with suspected or confirmed Lassa fever should apply extra infection control measures to prevent contact with the patient's blood and body fluids and contaminated surfaces or materials such as clothing and bedding. When in close contact (within 1 metre) of patients with Lassa fever, health-care workers should wear face protection (a face shield or a medical mask and goggles), a clean, non-sterile long-sleeved gown, and gloves (sterile gloves for some procedures).

Laboratory workers are also at risk. Samples taken from humans and animals for investigation of Lassa virus infection should be handled by trained staff and processed in suitably equipped laboratories.

On rare occasions, travellers from areas where Lassa fever is endemic export the disease to other countries. Although malaria, typhoid fever, and many other tropical infections are much more common, the diagnosis of Lassa fever should be considered in febrile patients returning from West Africa, especially if they have had exposures in rural areas or hospitals in countries where Lassa fever is known to be endemic. Health-care workers seeing a patient suspected to have Lassa fever should immediately contact local and national experts for advice and to arrange for laboratory testing. 

[MetroHealth HMO Limited, 2016 and World Health Organisation (WHO), 2016]