The worm doctor

8:30 a.m., 20 Appia Avenue in Geneva, WHO, Department for “Neglected Tropical Diseases”. Lester Chitsulo enters his office at the headquarters of the World Health Organization. Near the window is his desk, covered in paperwork. On the walls, private photographs hang alongside posters that show what has occupied him for a good 30 years: the cycle of schisotosomiasis and the parasite, the so-called schistosoma, that causes this worm disease, as the larvae penetrate the human body by coming into contact with the skin through infested water. Once there, the larvae spread through the veins and nest primarily in the bladder and intestines, causing itching as the larvae enter, skin rash, life-threatening fever, chills, cough, headache and the enlargement of the liver, lymph nodes and spleen.

The 57-year-old biologist and parasitologist studied in the United States and the United Kingdom. Area of specialization: schistosoma. His numerous publications on this topic are proof. But he began in his homeland Malawi. He grew up in the southern African country in conditions of poor hygiene and at 12 contracted schistosomiasis the first time, like nearly everyone his age. He was cured, but it wasn’t talked about much. It was normal to get sick like that: this disease affected nearly 50 percent of school children in Malawi at the time. He swore to himself: “I want to change something.” He knew that he would only succeed through education, not by herding goats. So he was very hardworking at school – and ambitious.

After his studies, he first began work as a biology teacher. But everyone who knew him knew from conversations that he was interested in schistosomiasis and its pathogenic organisms and wanted to dedicate himself completely to this area. When the United Kingdom initiated a project to control and contain schistosomiasis in Malawi in 1979 and was looking for a project worker in the Ministry of Health there, Lester Chitsulo’s time had come. He got the job, got sick with schistosomiasis again and was once again cured. A key experience for him and his further career: “I was completely surprised, when I saw the worm eggs in my urine sample under the microscope. They really jumped out at me,” he said. Since then, he has completely devoted himself to studying the schistosoma and fighting the parasitic worms.

Lester Chitsulo lived in two worlds: he worked on his doctorate and research interests in the United States and Great Britain, but he also returned repeatedly to Malawi, where he had a brilliant career in the Ministry of Health. In 1997, he went to Geneva to work at the WHO – something he would not even have dreamed of. “I was fortunate to get this job,” he says. There he investigates various tropical diseases – including schistosomiasis. He also coordinates control efforts on other worm diseases.

In this position he is also responsible for the Merck Praziquantel Donation Program. The company has been supporting the WHO’s global anti-schistosomiasis initiative since 2007.
Until 2017 the pharmaceutical company will donate the drug Cesol® 600 containing the active ingredient praziquantel – 200 million tablets with a value of about US$ 80 million. “Praziquantel is the only available and effective treatment for all forms of schistosomiasis, with only a few, temporary side effects,” as Chitsulo explains, who was also cured by the same drug.

The control effort focuses on school-aged children because they are most at risk by the infested water they play, fish or bathe in. One bout of illness can disrupt their growth and they could have learning difficulties as a result. Treatment with praziquantel three times during childhood also reduces the risk of developing disease as an adult. A total of 27 million children can be treated with the donated tablets; over five million children have received it so far.