Mango tree investors fight sleeping sickness

In the DR Congo, a mobile team of doctors are performing complex operations to cure sleeping sickness, which has seen a dramatic increase in infection rates in recent years

Under the mango tree next to the mud-brick community centre, there is a serology table with a small centrifuge, powered by a Land Rover battery. Nearby is a parasitology table with two microscopes, one to examine wet blood for sight of the question mark-shaped parasite; the other for lymph node 'juice'. By the administration table is a small queue of families waiting to have their fingers pricked. In between, in the deep shade, is the chair where a lumbar puncture will be done if one of these tests suggest a person has the trypanosome which causes sleeping sickness.

Lumbar puncture? Even those who believe that all these other tests can be done accurately under a mango tree in the bush beside the Congo River might balk at carrying out this investigation which means puncturing the spinal column to extract fluid.

In other countries, lumbar punctures are only done under sterile conditions. But, says Dr Simon van Nieuwenhove, who is WHO's regional adviser on trypanosomiasis, 'If I had to have a lumbar puncture, I'd rather have it here because these guys do hundreds every year.'

The 'guys' are one of 35 mobile teams fighting trypanosomiasis or sleeping sickness in the Democratic Republic of Congo (DRC). Covering some of the most remote areas of land in the continent, the unique teams use blood, lymph and cerebrospinal fluid investigations to systematically screen populations at risk — 12.6m people in DRC — from the bite of the tsetse fly. The infected people can in many cases be completely cured. Early detection of this disease, which relies on infected humans for its spread, is crucial.

The mobile team started in the DRC during an outbreak of sleeping sickness in the 1920s. Around 250 teams searched the country for infected people and by the 1960s, they had reduced new infections to under a thousand a year.

However, with the breakdown of control activities after independence and the trypanosome apparently on the run, mobile teams were reduced and most people forgot about sleeping sickness.

resurgence in the disease

When the first inklings of a resurgence began in the 1960s, a small number of teams resumed work, but with the withdrawal of bilateral aid in the early 1990s this system collapsed. By 1998 reported new cases were peaking at 26,000 a year and this is only the tip of the iceberg. The current 35 teams are reaching less than 12% of the population at risk, and the real figure already infected is likely to be more than 100,000.

But here, under the mango tree, six men, employees of the Congolese Ministry of Health's Bureau Central de la Trypanosomiase, are part of the fight against this disease. In the back of the Land Rover, they have everything needed to accurately diagnose sleeping sickness.

Unlike the old days when diagnosis focused on finding swollen lymph glands and examining lymph 'juice' they pre-test with the blood-based Card Agglutination Trypanosomiasis Test (CATT) which uncovers up to three times more people with the parasite, before looking for the live parasite microscopically.

'In some areas, you can miss up to 80% of cases with just lymph node palpitation, which means you are leaving a large part of the human reservoir,' says van Nieuwenhove.

The CATT has another clever characteristic. As the centrifuge gently evolves, the owners of the small circles of blood can see with their own eyes the grainy wave of sediment that the blue stain produces if they have the trypanosome antibody in their blood.

'When people are informed that they are positive, no-one refuses the lumbar puncture needed to confirm the diagnosis', says the mobile team leader Mr Bongo. 'This is much better than asking people to go to a clinic far away to find out if they are sick or not. Transport is difficult and expensive and if we don't do it here, we could lose many patients.'

free treatment

A few kilometres away, infected patients found by the mobile ream are staying at the small colonial-built clinic of Maluku, 80km up the Congo River from Kinshasa. Here, Mr Chamba, a nurse specialist in sleeping sickness after four years with the programme, administers the free treatment and monitors patients with blood tests and lumbar puncture.

Two of the current patients are a mother and child — the mother in the first stages of the disease, the child with the almost imperceptible shake of early second stage infection. Both have started treatment and should, says Mr Chamba, react well. Sleeping sickness tends to attack families when exposed to the same environment that harbours the fly. Another patient has been brought by his mother all the way from Kinshasa for testing and treatment. He can barely sit up, tremors quite violently and has the frozen stare classic of someone with a head full of trypanosomes.

early symptoms

One of the problems with sleeping sickness is that its early symptoms — fever, headache, joint pains, itching for a few days — are innocuous in a country where, on average, children have 10 episodes of malaria-like fever a year. Plus after the initial symptoms there is little to indicate the coming danger. Between six months and five years or more, however, the parasite multiplies and mutates until it crosses the blood brain barrier and penetrates the neural system. As the brain reacts with swelling and inflammation, blood vessels and nerves get squeezed, and the person develops neurological symptoms and becomes vague and unreactive. Finally, if not treated, the sleep and lethargy of the disease's name arrives followed by death.

Current treatments can cure even late stage disease but neurological damage often remains. 'You may not see it openly, but a person who has had advanced sleeping sickness and recovered is unlikely to be the person they were before,' says van Nieuwenhove.

complex treatment

Sleeping sickness is complex to treat. The main drug for the second phase is particularly strong. It is usually described as a mixture of arsenic and anti-freeze and has to be administered by injection with all the accompanying difficulties of sterilisation and attendance. Treatment lasts for 30 days. Even when treatment has been completed properly, the parasite can reappear up to two years afterwards. The only way to be sure that a patient is cured, and no longer a reservoir, is to follow up with them for two years wherever they are and do a lumbar puncture every six months, hard enough in countries with buses, taxis, trains, planes, unlimited supplies of fuel and, above all, peace.

Until last month, there was also the additional fear that the only drugs that can treat the disease were about to go out of production, leaving the half a million Africans currently with the disease without hope of treatment. But, with the launch in May of a $25m initiative between WHO, international health NGO Medecins Sans FrontiEres and pharmaceutical manufacturers Aventis Pharma and Bristol-Myers Squibb, not only have drug supplies been assured, free of charge, for the next five years, but there is also some money to increase the number of mobile surveillance teams and to do research on better treatment regimens.

'The initiative has changed the situation dramatically. First, it gives us the drugs that would have disappeared and, secondly, most of the cost of the trypanosomiasis programme is drugs. Now, with the pharmaceutical companies giving the drugs free, much of this money will be reallocated to increase screening.'

In fact, controlling sleeping sickness should be relatively easy. Nature has given trypanosome an extremely difficult path to humans. The tsetse fly produces only about 10 larvae during its three month life span, and a young fly has to feed on an infected human within a few hours of emerging, otherwise its salivary glands seal and the trypanosome can't get in. Once infected, the fly needs shade and humidity to survive and can infect more than 20 people in its lifetime.

national programme

Although, even in highly endemic areas, there are relatively few infected flies and some initiatives have focused efforts on getting rid of the insects themselves, the weak link in the transmission chain is the infected human. Remove the human reservoir and you remove the disease, says van Nieuwenhove.

In DRC the national programme with its focus on mobile teams is a model for other countries. Co-ordinated by the Bureau Central de la Trypanosomiase, it is funded to the tune of $2.5m a year from the Belgian Government.

The Belgian Government has also given $1.5m to WHO's African Regional Office for the next two years to support co-ordination and development of similar programmes against the disease which affects 36 countries in Africa.

But there is still much to be done. Less than 12% of the at-risk population in DRC is being screened at the moment. With the promise of peace, there is hope that populations deep in the jungle-bound basin of the Congo River and its tributaries where functioning healthcare is a thing of history will become accessible. Many more mobile teams and functioning treatment clinics will be needed.

Areas long thought free of sleeping sickness are also showing alarming rates of disease. When a whole family from the Kinshasa suburb of Nbgili turned up sick at Dr Chamba's Maluku Clinic, the mobile team went back with them and found 118 cases among their neighbours.

And in the heavily packed shanty towns surrounding DRC's capital city, Kinshasa, a city of 7m people, an infected tsetse fly can do a lot of damage.