Challenges and Innovative Strategies to Interrupt Cryptosporidium Transmission in Resource-Limited Settings

Abstract

In addition to Cryptosporidium being recognized as a very important cause of morbidity and mortality among humans, it is also an important economical problem with hundreds of outbreaks reported throughout the world every year and in agriculture where it affects mostly young animals. Transmission of Cryptosporidium is often by oral route through water and food. Although Cryptosporidium is most prevalent in resource-constrained areas, the majority of studies on the disease transmission have been conducted in developed countries. The control of Cryptosporidium has progressed over time, and with the development of new and more powerful methods in diagnostics and genomics, it has become much easier to detect Cryptosporidium and conduct genotypic analysis which could help to identify the sources of infection via anthroponotic (Cryptosporidium hominis) or both anthroponotic and zoonotic (Cryptosporidium parvum) routes. While detection methods have improved, determining Cryptosporidium viability and, therefore, effectives of inactivation remains a challenge. Control measures are directed at reducing and/or preventing transmission of the infective oocysts to the humans and animals. The tough nature of the oocyst makes traditional water treatment processes such as coagulation/flocculation, sedimentation, filtration, and disinfection insufficient to remove the parasite. Nitazoxanide, the only FDA-approved drug for the treatment of cryptosporidiosis, may reduce oocyst shedding and can lead to both clinical and microbiological cure, but it is ineffective in HIV-positive and AIDS patients, and studies in malnourished children have mixed results. The investigation of the importance of traditional medicines used commonly in developing countries has undetermined efficacy, because of the lack of validated experimental models. Collaborative research between developed and developing countries is critical for the advancement of our understanding of the control measures to be used to stop the transmission of Cryptosporidium. An example of an international multidisciplinary partnership between two research institutions addressing innovative means toward interrupting Cryptosporidium transmission is discussed.