WRITTEN BY PROF PETER KATCHY
Lassa Fever made a dramatic appearance in Nigeria in January, 1969 as a lethal, highly transmissible, hitherto unknown disease.

The first victim was an American missionary nurse who was infected at a small mission station in Lassa Township in Borno State from whence the virus derives its name.
Lassa Fever has a wide spectrum of disease from subclinical to fulminating fatal infection. The incubation period ranges from 3 to 16 days and the illness usually begins insidiously with feverishness, chilliness, malaise and muscular pains followed by Fever, headache, and sore throat. The disease may not be recognized until the later stages when the intensity of the illness increases. Cough is a common symptom and light-headedness.
 Lassa virus is pans tropic and causes or malfunction in liver, kidney, lungs, brain, skeletal muscle, and pleura. The absence of characteristic signs or symptoms in the early stages of infection makes clinical diagnosis difficult unless there is a history of contact with a known case or else there is a local outbreak as is the case in Ebonyi state.
The possibility of Lassa Fever should be considered whenever a patient from an endemic area presents with an unexplained febrile illness of relatively slow onset. A detailed travel history is relevant because Lassa Fever is only endemic in West Africa. The differential diagnosis in the early acute stage would include malaria, typhoid fever, typhus, influenza, yellow fever and other virus infections
The laboratory diagnosis of Lassa Fever is confirmed by isolating the virus from the patient’s blood or urine; or by demonstrating a serological response to Lassa Fever in serum. Lassa virus grows readily in Vero cell culture and isolation of the virus can usually be achieved within four days. Virus isolation should only be attempted in laboratories specially equipped to provide maximum containment to protect in the investigator. Therefore, any patient with suspected or confirmed Lassa Fever should be immediately placed on isolation. Some hospitals have special facilities which are designed to prevent contamination of the area outside the patient’s immediate environment. Lassa Fever is generally diagnosed in medical facilities which have no specialized containment areas. In these cases strict isolation and barrier nursing should be carried out without delay.
To minimize the risk of transmitting Lassa virus to medical and nursing staff caring for the patient, several precautions should be undertaken. The patient should be placed in a private room which should only entered through an anteroom. Ideally the isolation facility should be in a separate building. Hospital staff should wear-gowns, boots and caps. The anteroom should have washing facilities and should have supplies of protective clothing and facilities for disposal of soiled and contaminated articles.
Access to the patient’s room and anteroom should be limited only to those responsible for the care of the patient. A chemical toilet should be provided for the patient and all excreta treated with sodium hypochlorite. All objects for removal from the isolation facility should be double-bagged in sealed plastic bags and the outside should be washed in hypochlorite solution before removal.
Lassa Virus appears to have a natural cycle of transmission in rodents, especially rats. The animals are infected at birth or during the prenatal period and remain infective during their lifetime, freely excreting Lassa virus in urine and other body fluids. Primary infection in humans is thought to be acquired directly from infected rodent urine or indirectly from foodstuffs or dust contaminated by urine.
Low sanitation, storage of food within houses and the ease with which rodents can infest houses are said to increase contact between rodents and humans. There is still no Vaccine available for prophylactic immunization. The best means of control might well be in controlling the rodent populations by the use of rodenticides in houses and in villages where there are a high rate of transmission.
Health education campaigns, adapted to local culture and beliefs, should promote the adoption of appropriate hygiene practices such as hand-washing with soap, safe preparation and storage of food, breastfeeding, and environmental sanitation and deployment of rodenticides.
Sequel to the recent outbreak of Lassa Fever in Ebonyi and Nasarawa States, it becomes very pertinent to inform Ndi Anambra that there has not been any case of Lassa Fever in the state, according to the State Ministry of Health Officials.

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