Cyclosporiasis is an emerging public health concern worldwide which causes gastroenteritis, abdominal pain and weight loss, and is caused by the coccidian protozoan Cyclospora cayetanensis. Over the years, scientists have tried to elucidate its biology and epidemiology but this has been complicated by lack of information on the pathogen's origins and animal reservoirs if any do exist for this parasite. Studies have reported three new Cyclospora species reported in the East African non-human primates which are morphologically similar to human C. cayetensis. The African green monkey is susceptible to infection and hence presents a suitable model for studying Cyclospora-like organisms in the laboratory and including association with HIV in the human disease as it harbours Simian immunodeficiency virus. The analysis of clinical, pathological findings of Cyclospora provides new understanding of the disease process. Successful experimental establishment of Cyclospora infection as described in this book therefore provides information that would be very useful to health practitioners for the development and evaluation of therapies and control strategies for HIV and Cyclospora infections.