LASSA FEVER: Symptoms, Causes, Treatment and Prevention.

Dr Malik has been recuperating from an illness that gave him a near death experience. It has been one long month in hospital and he remains in isolation but he is grateful that he is alive irrespective of the short comings in the level of care he was initially getting. Things are somewhat improved at least to the extent that other healthcare workers that come to the isolation ward can talk to him with less apprehension for their own safety.

It was a scary experience but Dr Malik is lucky to be alive. The other three members of his team were not as lucky.

It started as a normal work day for Dr Malik's Obstetric team. They received a pregnant woman who was referred from another Health Facility in respect of Emergency Operative Delivery. After observing due protocol they took the woman into the theater for surgery. That was where normality ended and everything abnormal began.

The patient died in the post operative period. Two of the Medical team members took ill and died a few days later. A third member was also ill. Dr Malik was away from work because of symptoms of what he thought was malaria.

An inquiry was already underway after the demise of the first two team members. It turned out that the patient that was operated upon had earlier returned from the burial of her own mother who died of a fever before presenting in hospital for childbirth. It was also found that the said community, hundreds of kilometers from Dr Maliks Center, was having a strange illness that was causing deaths among them. This strange illness was eventually confirmed to be Lassa fever.

Dr Malik was taken from his home into isolation and only understood why he was in isolation many days after detention! Everyone in the Healthcare facility was scared and understandably so.

Stories like the above happen from time to time in the healthcare space in Nigeria, further making healthcare staff an endangered species. The current Lassa fever outbreak in Nigeria has topped 1038 cases, resulting in 184 deaths and involving 17 States as reported by www.thenationonlineng.net.

CAUSES

Lassa fever is an animal-borne, or zoonotic, acute viral, haemorrhagic illness spread by the common African rat, mastomys natalensis. It is endemic in parts of West Africa including Sierra Leone, Liberia, Guinea and Nigeria. Neighboring countries are also at risk because the animal vector lives throughout the region.

The first documented case occurred in 1969. Lassa fever is named after the town in North Central, Nigeria where the first cases were identified.

Lassa fever is endemic in west Africa, where it probably kills several thousand people each year. With access to the region improving, the opportunity, and the need, to improve our understanding of this disease are increasing. There are geographical drivers of the disease that may not also be unrelated to the disease vector.

The disease is caused by a single stranded RNA virus and is a spread systemic primary viral infection. The main feature of this deadly disease is impaired or delayed cellular immunity leading to overwhelming viraemia. The prevalence of antibodies to the virus in the population is 8-52% in Sierra Leone, 4-55% in Guinea, and 21% in Nigeria. Seropositivity has also been found in the Central African Republic, Democratic Republic of the Congo, Mali, and Senegal. Staff from International Development and Aid Agencies have succumbed. And so have sporadic cases in travelers returning to Europe.

Nigeria had its largest Lassa fever outbreak in 2018. In 2019, 50 years after the disease was first identified, an International Conference was held in Abuja in which it was agreed that Lassa fever remained a difficult disease to diagnose and treat. Other highlights included:

Lassa fever is a viral haemorrhagic fever that spreads to humans through contact with infected rats.

“One of the major challenges of treating Lassa fever is the nature of the disease itself because at the onset, it mimics diseases like malaria,” says Dr Umezurike Daniel, the health commissioner of Nigeria’s Ebonyi state.

Only a few laboratories in the world can diagnose the virus—which often leads to delays in starting treatment.

“A lot of time is wasted before the patient actually presents for treatment, and the prognosis gets very bad if treatment is not commenced within six days from the onset of symptoms,” Dr Umezurike explains.

Managing Lassa fever also requires appropriate use of personal protective equipment and other infection prevention and control measures, to protect healthcare workers and relatives of patients.

SYMPTOMS

Lassa fever presents with symptoms and signs similar to those of febrile illnesses such as malaria and other viral haemorrhagic fevers such as Ebola. It is difficult to diagnose clinically but should be suspected in patients with fever (≥38°C) not responding adequately to antimalarial and antibiotic drugs. The most useful clinical predictors of Lassa fever are fever, pharyngitis, retrosternal chest pain, and proteinuria (protein in urine) for diagnosis; and fever, sore throat, and vomiting for outcome.

Complications include bleeding in the gums and other mucous membranes, sensorineural hearing deficit, pleural effusion, and pericardial effusion. The outcome is related to the viral load in the blood.

In the midst of an outbreak, all suspected cases should be admitted to isolation facilities. Inadequate infection control measures is the reason for hospital transmission. Strict isolation of cases and procedures for handling body fluids and excreta must therefore be necessarily maintained. Laboratory support should urgently be sought and procured.

TREATMENT

Fluid replacement or the use of blood transfusion requires careful monitoring, even though dehydration, hypotension, and poor renal function are common. General support and drug treatment with the antiviral drug Ribavrin are needed and may reduce deaths by 90% if given within 6 days of onset of illness. Ribavarin is twice effective when given intravenously as compared with when given orally.

PREVENTION

The causative agent Lassa virus and vector, Mastomys natalensis is becoming a topical issue despite the neglected tropical disease status of the disease. The primary transmission mode of Lassa virus has not been fully comprehended but several social and environmental factors have been implicated to either play a major role in determining the rate of transmission or exacerbating transmission risks. Nonetheless, some transmission route includes faeco-oral, rodent bites, and the consumption of rodent meat.

It is said that good community hygiene is at the heart of prevention of Lassa fever. Truthful as that may seem, however, that may be too simplistic a view. Cultural issues and food choices are also important as much as the methods of preservation of such foods.

In healthcare settings, use of Personal Protective Equipment and the psychological difficulties in proper deployment especially when Healthcare staff are ill is as important.

You may also like to read my earlier blogs on Cholera, Typhoid Fever, Climate Change, Malaria, Genital Herpes, Head Lice, Scabies, Telemedicine, Success Mindset, Conjuctivitis, Ebola Virus Disease, Hepatitis B, Measles, Ear infecion, and Meningitis.

We encourage active participation in community protection and personalized care.