Andrew Davis

Abstract

Pioneer of effective schistosomiasis control. Born in Washington, UK, on Jan 31, 1928, he died from coronary heart disease in Oxford, UK, on Jan 10, 2013, aged 84 years. On Feb 12, 2013, WHO signed an agreement under which the pharmaceutical company Merck KGaA promised to increase its annual donation of the anti-schistosomiasis drug praziquantel from 20 million tablets annually to 250 million. Lorenzo Savioli, head of WHO's Department of Control of Neglected Tropical Diseases, used the occasion to pay tribute to a former director of parasitic diseases. His sometime colleague, he said, had played “a pivotal role in the development and clinical trials of praziquantel, which radically changed the treatment and control of schistosomiasis”. His only regret was that he couldn't call the man to tell him that there was now enough of the drug to treat all school-age children in Africa at risk of the disease. The colleague of whom he spoke was Andrew Davis. Known by all as “Rikk” (a nickname acquired after his appearance in a school adaptation of Rikki-Tikki-Tavi, one of the Jungle Book stories of Rudyard Kipling), Davis graduated from Durham University's medical school in 1951 with the aim of becoming a clinical pharmacologist. National Service found him in the Royal Army Medical Corps, which posted him to Kenya. It was this experience, thinks his friend and colleague Alan Fenwick, that triggered Davis's interest in parasitology. Either way he was soon working in Tanga at the WHO/MRC Tanzanian Bilharziasis Chemotherapy Centre of which he was appointed Director in 1962. Praziquantel was not developed until the early 1970s, and Davis's period in Tanga focused on clinical trials of antimony preparations and, later, the organophosphorus compound metrifonate. Between 1971 and 1974 he was based in Jamaica at the MRC's Epidemiological Research Unit. His reputation was by this time well established, and Joe Cook, then working for the Rockefeller Foundation as a clinician with a schistosomiasis control project on the nearby island of St Lucia, enlisted him as an adviser. The work, which relied on injections of hycanthone, was successful. “In St Lucia we showed that chemotherapy was the most effective method of dealing with the disease”, says Cook. From Jamaica Davis moved to Geneva, becoming Director of WHO's Parasitic Diseases Programme. Around this time, praziquantel, the drug soon to become dominant in the control of schistosomiasis, was emerging into the limelight. “It was discovered by Bayer when they were screening drugs, and Rikk picked it up and ran with it”, says Fenwick, now Professor of Tropical Parasitology at Imperial College London. Davis was able to use WHO money to back it. “He devised phase 2 and phase 3 trials in centres through the tropical world and he really pushed Bayer to ensure it was taken to the next stage. Without him we wouldn't have praziquantel”, explains Fenwick. In the early days praziquantel, at a dollar a tablet, was still expensive, and many of the initial studies were on a small scale. In 1984 Savioli, who'd been working in Tanzania, was eager to start a bigger schistosomiasis chemotherapy control programme. His idea was to try it on the island of Pemba. He approached Davis, who thought it was an excellent scheme and said he had some funds that could be used to support a praziquantel programme. It was duly launched in 1985. The initial results revealed, among other benefits, a 65% reduction in haematuria, says Savioli: “It was fantastic. It was the first large scale demonstration that treating people with praziquantel dramatically reduced morbidity.” The drug was really Davis's baby, he adds. “There was a small group of people around the world who thought that large scale, single dose use of praziquantel would change completely the outlook for schistosomiasis infections, especially in sub-Saharan Africa. Rikk was one of the leaders of this pioneering concept. In WHO he was the one who really promoted the idea of using it. Where we are today is the outcome of the work that he and others did 30 years ago.” “Rikk was a huge presence, highly respected”, according to Fenwick. “A lot of fun”, says Cook. And Savioli offers his own recollection: “A big man, a sportsman in his youth, very authoritative, a tremendous leader. He had a distinguished gentleman style, always very elegant, very British.” This, it seems, was an image Davis played to by sporting a Marylebone Cricket Club tie and even, on occasion, a monocle. All three of his old colleagues agree about his contribution to parasitology. “He had a huge and encyclopaedic knowledge of helminthology”, Savioli recalls. Davis leaves a wife, a son, and a daughter.