Cryptosporidium infections in Sri Lanka: A Systematic Review.

Cryptosporidium is a protozoan parasite that causes gastroenteritis in both humans and animals. Cryptosporidium infections in humans and animals have been reported from many parts of Sri Lanka. During the present study, five international electronic databases were extensively searched for peer-reviewed research papers published on the prevalence of Cryptosporidium infections and their occurrence in probable sources in Sri Lanka, within the time frame from 1987 to 2023. Collected information revealed that Cryptosporidium oocysts are more commonly found in surface water compared to well water, and shallow wells have a higher occurrence than deep wells. Contamination of river water with Cryptosporidium is mainly from the faecal matter coming from various domestic, agricultural and wildlife animal species. In Sri Lanka, Cryptosporidium infections in captive non-human primates is possibly due to contaminated food and human interaction. In wild animals, infections are more common in species that feed on the ground, suggesting contaminated soil and water as the source of infection. Most of the infected animals are asymptomatic, and many had co-infections with other enteric parasites. Molecular analysis of Cryptosporidium samples from infected primates revealed the presence of four major clades of C. parvum, with some isolates closely related to zoonotic C. parvum genotypes. Information on the habitats of the infected primates suggests that livestock is the primary source of infection. Several studies have been conducted to investigate the prevalence of Cryptosporidium infection in various livestock animals, particularly in goats, cattle, buffaloes, and swine in Sri Lanka. These studies reveal high prevalence of asymptomatic Cryptosporidium infection in goats and the potential for the transmission of zoonotic C. parvum from goats, cattle and buffaloes to humans. Molecular epidemiological analysis identified new genotypes of Cryptosporidium in domestic bovids (cattle and water buffalo), with no evidence of the commonly reported zoonotic species C. parvum. Waterborne transmission is the most common mode of infection of Cryptosporidium that affect both humans and animals. Studies conducted in human populations are primarily based in hospitals and pre-schools, and conclude that Cryptosporidium infections are a common cause of diarrhoea in children under the age of five. In conclusion, Cryptosporidium infections occur in different species of animals and humans in Sri Lanka and the oocysts have been detected in surface water, which might be an important source of infection for animals and humans in the country. [ABSTRACT FROM AUTHOR]