Here we describe efforts to develop vaccines that combat hookworm and schistosomiasis, with an emphasis on disease caused by Necator americanus, the major hookworm of humans, and Schistosoma mansoni, the primary cause of intestinal schistosomiasis. Current efforts to control hookworm and schistosomiasis are inadequate and new tools are needed. However, when the chronic morbidities of these two infections are fully considered according to disability-adjusted life years (DALYs years of life lost owing to disability, ill health or death), hookworm and schistosomiasis combined rank among the most important diseases in developing countries, resulting in 4.5вЂ“92 million DALYs annually, the upper limit of which is greater than the DALYs due to malaria or HIV/AIDS 4, 5, 6. An important reason for this 'neglect' is that hookworm and schistosomiasis typically affect health without resulting in mortality, with infections such as HIV or malaria causing tenfold more deaths ( Table 1). Even the United Nations Millennium Development Goals for sustainable poverty reduction did not specifically mention these two conditions 10. Until recently, the importance of these conditions as global health and economic problems had been underappreciated. They also trap the world's poorest people in poverty because of their deleterious effects on child development and economic productivity 7, 8, 9. Together, their disease burdens exceed those of all other neglected tropical diseases 3, 4, 5, 6. In terms of their global health impact on children and pregnant women, as well as on adults engaged in subsistence farming, human hookworm infection (known as 'hookworm') and schistosomiasis are two of the most common and important human infections 1, 2. One of the leading schistosomiasis vaccines under development targets a tetraspanin antigen involved in biogenesis of the tegument of Schistosoma mansoni, the main etiological agent of intestinal schistosomiasis.Д«oth vaccines are being developed for children living in endemic areas of developing countries and could be linked to anthelmintic treatments in a programme of vaccine-linked chemotherapy.Д«oth the hookworm and schistosome antigens may ultimately be combined as a multivalent anthelmintic vaccine. Global control of each infection currently relies on mass drug administration using donated or low-cost anthelmintic drugs, but high rates of both drug failure (with mebendazole) and post-treatment reinfection necessitate the development of anthelmintic vaccines.ДЄ human hookworm vaccine is being developed as a bivalent injectable product combining two recombinant proteins, derived from the gut of the adult stage of the hookworm Necator americanus, that interfere with parasite blood feeding. Hookworm infection and schistosomiasis are two of the most common neglected tropical diseases of humans and among the most important in terms of their global disease burden in developing countries.

Untreated hookworms in humans