Lassa Fever in Sierra Leone: A Battle Against a Deadly Disease

2024-07-10 04:35:00

Hunting in the dark in a small mud house in the east Sierra Leoneecologist James Koninga removes a rat trap from a broken bed, an essential but necessary device against a deadly disease, the fever of Lassa.

James Koninga, 62, is part of a group of researchers studying Lassa fever, viral hemorrhagic disease endemic to some countriesWest Africa et transmitted by rodents.

He knows the effects: 30 years ago, the virus sent him, then a young scientist, to hospital with a fever, diarrhoea et headache. Twenty days gambling. “I saw myself leaving, I saw myself dying”he said.

Up to 15% case fatality rate

Ten years ago, another viral and hemorrhagic disease, Eboladeath and fear buried in West Africa.

Starting from Guinea, reaching Sierra Leone and Liberia, it caused the epidemic, the most serious since the discovery of the virus in 1976. more than 11,000 deaths in two years.

Sierra Leone has not had a case of Ebola since 2016, thanks in part to that vaccination.

The lessons of Ebola are now serving scientists in their next fight against Lassa fever, starting with the Kenema region, the first in Sierra Leone where Ebola was reported ten years ago.

At 1%, the death rate of Lassa fever is a far cry from Ebola (about 50% on average according to the World Health Organization). But it can reach 15% in patients with severe forms.

Limited treatments

Researchers are watching for the slightest sign of disease progression. THE number of stagnant casesbut they are scattered throughout the territory.

There is no no known vaccinetreatments are limited and doctors emerge, as with Ebola, obstacles that prevent early treatment, the best guarantee of a cure.

Watch for rodents vital in the Kenema region and in remote villages such as Mapuma, where James Koninga works today among houses under dense forest cover.

Five star hotels for rats

“Rats dig their holes inside houses” and they leave their droppings there, says James Koninga, wearing a mask and protective gloves. “If people come back from the bush with sores and lie on the bed, there is a risk of infection.”

Proximity to the bush, earthen constructions, open storage of grain and water… Dwellings are similar to Mapuma houses Five star hotels regarding rats, says Lansana Kanneh, 58, a field supervisor at the Kenema Government Hospital (KGH).

“Food is so scarce for humans that they sometimes eat food that is partially eaten by rodents,” he said. Traps can setters catch 20 rats per day.

They first confirm that the rodents of the genus Mastomys, the reservoir of the virus. They take samples that will be analyzed. The rats are released after an injection that blocks the transmission of the virus.

“We see cases from the end of the year”

The fever affects between 100,000 and 300,000 people a year in West Africa and kills about 5,000according to the African Centers for Disease Control and Prevention.

The figures are probably lower than the reality. Admissions to the specialist ward at Kenema Hospital, the only dedicated treatment center in Sierra Leone, have declined over the past 10 years. But the image is misleading.

Patients used to come during the dry season, between November and May, but now, “We see cases from the end of the year”says Dr Donald Grant, head of KGH’s Lassa Fever Programme.

And mortality among hospitalized patients has increased alarmingly more than 50%. “Sometimes they spend 24 or 48 hours in the hospital, and then they die”Lansana Kanneh reports.

The team is observing an increase in cases outside areas that were endemic. Dr Grant mentions the expansion of human activities in the forest, bringing them closer to rats.

Vaccine in the testing phase

It is essential to detect the problem as soon as possible. However, the first signs such as fever attacks can be confused with symptoms malariaof cholera or the typhoid.

The distance from doctors and several hours of bumpy roads do not encourage people to seek care. The memory of Ebola, which claimed the lives of around 4,000 Sierra Leoneans, remains strong.

“People believed that health workers were the ones who transmitted Ebola,” Lansana Kanneh remembers. Dr Grant hopes for an approved vaccine in the coming years.

There is currently a vaccine that an intermediate stage of the clinical trial on hundreds of people in Nigeria and Liberia.

In the meantime, the doctor asks to remain vigilant. Ebola “It taught us that we must wait for the critical point where (the epidemic) will overwhelm us all”he said. “Now is the time to act”.