CHSSAG PRESS RELEASE ON THE CURRENT LASSA FEVER OUTBREAK IN NIGERIA

Fellow students, in the past few days there has been an outbreak in some states such as Taraba, Niger, Nassarawa, Bauchi, Kano and Rivers States, leaving some people dead and others hospitalised.

Lassa virus is a member of the arenavirus family. The disease was first described in the 1950s, and the virus was identified in 1969, when 2 missionary nurses died from it in the town of Lassa in Nigeria.

Transmission

Lassa virus is present in rats, which shed the virus in their urine and droppings. These are common in rural areas of tropical Africa, and often live in or around homes. Once infected, rodents shed virus throughout their life.

Transmission of Lassa virus to humans normally occurs through contamination of broken skin or mucous membranes via direct or indirect contact with infected rodent excreta, on floors, home surfaces, in food or water. Transmission is also possible where rodents are caught and consumed as food.

Person to person transmission occurs through infected bodily fluids, such as blood, saliva, urine or semen.

This transmission can happen:

• in the laboratory
• in a healthcare setting
• via sexual or other close contact

Transmission to close contacts usually only occurs while the patient has symptoms. However, a patient can excrete virus in urine for between 3 and 9 weeks after the onset of illness. Patients can transmit the virus via semen for up to 3 months.

Symptoms

Infection is mild or asymptomatic in 80% of cases, but can cause severe illness and is fatal in approximately 1 to 3% of patients. The incubation period for disease is usually between 7 and 10 days, with a maximum of 21 days.

The onset of illness is insidious, with:

• fever and shivering
• malaise
• headache
• generalised aching
• sore throat

Nausea, vomiting, diarrhoea or cough can accompany these symptoms.

An important diagnostic feature is the appearance of patches of white or yellowish exudate and occasionally small vesicles or shallow ulcers on the tonsils and pharynx.

As the illness progresses the body temperature can rise to 41ºC with daily fluctuations of 2 to 3ºC.

Extreme lethargy and exhaustion can occur in severe attacks, that is disproportionate to the level of fever. During the second week of illness symptoms include:

• oedema of the head and neck
• encephalopathy
• pleural effusion
• ascites.

Renal and circulatory failure may occur, aggravated by vomiting and diarrhoea.

In the severest cases bleeding into the skin, mucosae and deeper tissues occurs, usually leading to death.

Symptoms in children are similar to those in adults, but infant infection can result in ‘swollen baby syndrome’ with oedema, abdominal distension, bleeding and often death.

Diagnosis

Clinical diagnosis of Lassa fever is difficult. It can be confused with other infections such as severe malaria, typhoid fever, and other viral haemorrhagic fevers.

RT-PCR for nucleic acid detection, virus isolation or antibody detection methods can diagnose Lassa fever.

Treatment

Treatment with the antiviral drug ribavirin is most effective when started within the first 6 days of illness, and should be given intravenously for 6 days.

Supportive care such as fluid replacement, blood transfusion or other appropriate measures is also essential.

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Prevention and control

There is no licensed vaccine for Lassa fever. In endemic areas, rodent control and avoiding contact with rodents and their excreta helps prevent infection. Infection control includes storing food in rat proof containers.

Avoiding contact with bodily fluids of an infected patient prevents person to person spread. In healthcare settings these infection control measures include

• special barrier nursing procedures
• VHF isolation precautions to isolate infected patients
• wearing protective clothing for contact with the patient

Once the patient has recovered they are only infectious via semen and urine. Patients must avoid sexual intercourse for 3 months.

People living in endemic areas of West Africa with high populations of rodents are most at risk of Lassa fever. Imported cases rarely occur elsewhere in the world. Such cases are almost exclusively in persons who work in endemic areas in high risk occupations such as medical or other aid workers.

·         Ensure you store foods in rat proof containers and cook all foods thoroughly before eating.

·         Discourage rodents from entering the house by blocking all possible entry points.

·         For food manufacturers and handlers, do not spread food where rats can have access to it.

·         All fluids from an infected person are extremely dangerous.

·         Lodge presidents should liaise with their landlords to fumigate their lodges.

·         Students who go for posting are also advised to be at alert, wear personal protective equipment, observe universal basic precautions, nurse suspected cases in isolation and report same to your Unit head immediately.

·         We have already recommended that the CC Hostel should be fumigated as a matter of urgency.

                                                                                                    SIGNED:

COMR. FII TORNUBARI SAMUEL,

                                                                                      CHS-SAG PRO