Spotlight on health

Mango tree investigators fight sleeping sickness
by Hilary Bower

28 June 2001, Maluku, Democratic Republic of Congo -- Thousands of people in Sub Saharan Africa are dying and being damaged by a disease thought banished 30 years ago. Now in the war-scared lands of the Democratic Republic of Congo, health workers are fighting back and hoping the outbreak of peace in the human war will let them do more.

Under the mango tree next to the mud-brick community centre, there is a serology table with a small centrifuge, powered by the Landrover 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, and 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 if 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 and is, in other countries, only done under sterile conditions. But, says WHO's Dr Simon Van Nieuwenhove: "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. 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 - some 12.6 million people in DRC - from the bite of the river-loving tse-tse fly. The infected people they discover can in many cases be completely cured, but finding this disease, which relies infected humans for its spread, early is crucial.

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

When the first inklings of a resurgence began in the 1960s, a small number of mobile teams resumed work, but the withdrawal of bilateral aid in the early 1990s saw everything collapse. By 1998 reported new cases were peaking at 26,000 a year, and this, say experts, is only the tip of the iceberg. The current 35 teams are reaching less than 12% of the population at risk, and even neurological specialists have lost their alertness to the symptoms. The real figures of already infected but not yet diagnosed individuals are likely to be more than 100,000 - more unseen casualties of war and mismanagement that has devastated the country's health services.

But here, under the mango tree, the six men, employees of the Congolese Ministry of Health's Bureau Central de la Trypansomiase (Central Office for Trypanosomiasis) are part of the fight-back. In the back of the Landrover, 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 or 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 Dr Van Nieuwenhove who is WHO's regional adviser on trypanosomiasis and pioneered the CATT first in Sudan and now in DRC. The CATT has another clever characteristic. As the centrifuge gently revolves, 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 trypansome 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 for a lumbar puncture at 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 lose many patients."

A few kilometres away, infected patients found by the mobile team are staying at the small colonial-built clinic of Maluku, 80 kilometres 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 they are exposed to the same environment that harbours the fly. Another patient - a young man in a bad way - 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.

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. Over anything up to 6 months to more than 5 years, however, the parasite multiples 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 Dr Van Nieuwenhove. Sleeping sickness is complex to treat. The main drug for the second phase particularly is strong - usually described as a mixture of arsenic and anti-freeze - and has to be administer 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 them up for 2 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 $25 million initiative between WHO, international health NGO Médecins Sans Frontières and pharmaceutical manufacturers Aventis Pharma and Bayer, 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 we thought would disappear and secondly most of the cost of the trypanosomiasis programme is drugs. Now the pharmaceutical companies are giving the drugs free, much of this money will be able to be reallocated to increase screening," says Dr Van Nieuwenhove.

In fact, controlling sleeping sickness should be relatively easy. Nature has given the trypanosome an extremely difficult path to humans. The tse-tse fly produces only about 10 larvae during its entire lifespan (an average 3 months), not the massive dump of eggs common to most flies, and a young fly has to feed on an infected human within a few hours of emerging, otherwise its salivary glands seal and the trypansome can't get in. Once infected the fly needs a particular level of shade and humidity to survive and can infect more than 20 people in its lifetime. Although even in highly endemic areas there are relative few infected flies and some 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 Dr Van Nieuwenhove.

In DRC the national programme with its focus on mobile teams is a model for other countries. Coordinated by the Bureau Central de la Trypansomiase, it is funded to the tune of $2.5 million a year from the Belgian Government. The Belgian Government has also given $1.5 million to WHO's African Regional Office for the next two years to support regional 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 and its tributaries where functioning health care is a thing of history will become accessible, but many more mobile teams and functioning treatment clinics will be needed. Plus 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 cram-packed shanty towns of the now 7-million person city, an infected tse-tse fly can do a lot of damage.

For further information please contact: WHO Kinshasa: Dr Simon Van Nieuwenhove, African Regional Adviser for Trypanosomiasis, 001 321 953 9001, svn_30@hotmail.com' This document was researched and written by Hilary Bower, information officer for WHO Emergency and Humanitarian Action Department, Geneva, The content does not necessarily reflect official WHO views or policies. For further information, please email bowerh@who.int or hbower26@hotmail.com.