CRYPTOSPORIDIUM AND CRYPTOSPORIDIOSIS: A BRIEF REVIEW

Summary Siddiki, A. M. A. M. Z. & M. Masuduzzaman. 2009. Cryptosporidium and cryptosporidiosis: A brief review. Bulg. J. Vet. Med., 12, No 2, 91−111. Cryptosporidium parvum is an important zoonotic protozoan that has been found in human and animal populations throughout the world. It has a predilection for epithelial cells in the digestive tracts of a wide variety of hosts (humans, livestock, companion animals, wildlife, birds, reptiles and fish). The zoonotic form of infection was also reported by many investigators and led to many cross transmission studies to understand the complex epidemiology of cryptosporidiosis. More importantly, the opportunistic pathogen can produce an infection that may be chronic and even life-threatening for undernourished infants and AIDS patients. The waterborne transmission through drinking water or swimming pool is quite common resulting in a number of outbreaks in many countries worldwide. While many physical and chemical methods are employed to remove the oocysts from drinking water, it is still difficult to completely remove it through any single technique. The parasite has a unique intracellular but extracytoplasmic location and several other unusual features like presence of relict mitochondria, unique life cycle features like production of two types of oocysts, ability to autoinfection and lack of host specificity. Until now numerous in vivo and in vitro drug trials have been conducted against this important opportunistic pathogen but none was found to be completely effective against cryptosporidiosis. Recent release of complete genome sequences for C. parvum and C. hominis has facilitated further studies of this pathogen. It is expected that the use of modern bioinformatic tools along with mass spectrometry can be very useful to understand the global proteome of this parasite. Efforts to design a satisfactory treatment of cryptosporidiosis have not been successful due to a lack of understanding of basic cellular and molecular biology of the parasite. Therefore, considerable research is underway to explore the biology of C. parvum which will eventually lead to identification of suitable drug targets. In this review we attempted to highlight different biological aspects of Cryptosporidium along with present status of research and future directions.