Parasitic Infection in China: Farewell to the God of Plagues

Abstract

Initiated in 1996, with support from the United States’ National Institute of Allergy and Infectious Diseases, the Tropical Medicine Research Center (TMRC) at the Institute of Parasitic Diseases undertook a programme of research focused on helminth diseases of public health significance to China. In collaboration with investigators from the USA and Australia, the research seeks to gain a better understanding of the epidemiology and natural history of schistosomiasis japonicum and hookworm disease and to develop vaccines to control these diseases. The TMRC, directed by Feng Zheng, consists of three projects and core facilities. The core facilities provide resources for molecular biological, genetic and biochemical methods needed in the individual projects. In addition, these facilities provide support for relational databases and for repositories of biological samples collected from different geographic regions.Project 1 of the TMRC, headed by Liu Shu-Xian in collaboration with Donald McManus (Queensland Institute of Medical Research, Australia), seeks to further the development of recombinant S. japonicum antigens as vaccine candidates. Epidemiological studies are being undertaken to evaluate the potential benefit of a veterinary vaccine in reducing human schistosomiasis. Studies conducted in collaboration with George Davis (Academy of Natural Sciences, Philadelphia, PA, USA) are determining the genetic diversity within S. japonicum populations in the provinces bordering the Yangtse River. In addition to the relevance of these studies to vaccine development, the investigation seeks to establish relationships between different schistosome populations and their snail vectors, the subject of TMRC Project 2.Under the direction of F.X. Xie, and in collaboration with George Davis, TMRC Project 2 is characterizing the molecular diversity of snails of the genus Oncomelania, vectors of S. japonicum, and related pomatiopsid snails. These studies seek to establish evolutionary relationships among these organisms and their patterns of ecological distribution. In conjunction with the results from Project 1, the ultimate goal is to establish the molecular basis of the host–parasite relationship.The third project supported by the TMRC focuses on hookworm infections and is headed by Xiao Shu-hua in collaboration with Peter Hotez (Yale University, New Haven, CT). The studies are employing molecular methods to characterize the molecular diversity within populations of Ancylostoma duodenale and Necator americanus, the causative agents of hookworm disease in China. Vaccine studies have been initiated using a mouse model and recombinant antigens from the related hookworm of dogs, A. caninum; homologues are being identified in the hookworms of humans. Complementary to these investigations are immunoepidemiological studies to examine human correlates of protective immunity.The TMRC programme is currently in its third year of a five-year funding cycle.