Lyme disease: the forgotten scourge of West Africa

In the small village of Sindia, 70 km from Dakar, the landscape is dotted with the burrows of rodents. They may not be easy to spot, but even more difficult to see are the swarms of ticks that also make their home there and whose bite poses a serious health threat to the local population.

These ticks can carry Lyme disease, a potentially life-threatening sickness in humans that is becoming more common throughout West Africa.

“Lyme disease is a bacterial sickness,” said George Diatta, a zoologist at the Institute for Research and Development (IRD) in Dakar. “It is transmitted through the bite of Ornithodoros sonrai, a mole tick.”

The tick bite is usually painless, and often goes unnoticed, but its consequences can be devastating. Within seven days of infection, a person can experience a high fever that reoccurs every few weeks over a period of three months. Even more troubling, Lyme disease can trigger encephalitis, an inflammation of the brain that can be fatal.

One of the problems for controlling and treating Lyme disease is that it is difficult to diagnose. Its symptoms resemble those of malaria, and in rural areas, where Lyme disease is more common, resources to perform tests are mostly unavailable. When it remains undetected, symptoms can escalate and lead to death.

“It is difficult to pinpoint Lyme disease,” said Diatta. “A test needs to be done when the patient shows a spike in fever. But the disease being difficult to spot in the blood, you need a very experienced lab technician to detect it.”

From 1990 to 2003, researchers with the IRD studying malaria in the village of Dielmo in the Sine Saloum region of Senegal, took advantage of the resources available to them to also look into the prevalence of Lyme disease.

The results of their 14-year study showed that between 4 and 25 percent of the population presented cases of the tick fever, with an average rate of incidence of 11 percent per year. Other studies conducted in rural parts of Senegal, Mali and Mauritania confirmed these results.

“It’s a significant rate of incidence for a sickness that affects all age groups,” said Diatta. “Only malaria and the flu are as frequent, and we estimate that, like other endemic sicknesses, Lyme disease is a serious public health problem.”

The propagation of this bacterial infection in West Africa is due in large part to increasingly longer periods of drought. This has caused ticks to spread into areas outside of the Sahel region and into rural zones that receive less than 750 mm of rain per year.

In Senegal, ticks are present in two-thirds of the country, reaching as far south as the border with The Gambia.

A forgotten killer

Believing Lyme disease was eradicated in the 1950s, it quickly fell off the radar of health professionals and out of the public consciousness, making it virtually unknown to local populations today, explained Diatta.

The inhabitants of Sindia undoubtedly suffer from this lack of information.

“I’d never heard of this sickness,” said Hassan Ndione, a local villager, who expressed concern when told about Lyme disease. “I have rats and mice in my house, so I would imagine that there are ticks that could be biting us.”

According to Diatta, there is no viable way to eliminate the ticks without also destroying the rodent population, which would create an imbalance in the region’s ecosystem. He feels that the only way to contain the spread of the disease is to inform healthcare workers and the public about its existence and symptoms.

“What is essential is that health officials are vigilant about diagnosis and treatment. And to achieve that, universities and medical schools need to teach students about Lyme disease, to make them understand that when a high fever presents itself for more than three days, it is not malaria, but Lyme disease,” said Diatta.

“Recurrent malarias are often attributed to a resistance to anti-malarial medications, whereas these are cases of Lyme disease that can be easily treated with antibiotics costing no more than 2000 CFA (US $4),” he said.

As for research, he said more needs to be done as Lyme disease in West Africa is fatal and its real incidence remains unknown. Until then, Diatta and his fellow researchers at IRD say they continue their work with the hope that government officials and international organisations will take note and mobilise aid to help deal with this public health problem.

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