Global epidemiology and species/genotype distribution of Cryptosporidium in camels: A systematic review and meta-analysis

This review analyzed reported data of Cryptosporidium prevalence in camels and the species/genotype distribution. Four databases (PubMed, Web of Science, Scopus, Google Scholar) were screened, and studies published by April 1, 2024, were included. Total estimates and 95% CIs were calculated using a random-effects model. The weighted prevalence of Cryptosporidium spp. in 7372 camels examined from 12 different countries was estimated at 13.8% with a 95% CI of 10.3-18.4%. The sensitivity analysis based on excluding the individual studies did not result in significant statistical changes in the final weighted prevalence. Subgroup prevalence of Cryptosporidium spp. in camels was analyzed by publication year, continent, WHO region, country, camel type, sample size, diagnostic method, age, and gender. A significant publication bias (P < 0.05) was reported in the present study. Limitations encountered in this study encompassed: insufficient study diversity, reliance on single study results, inadequate molecular and serological studies in comparison to microscopic studies, etc., all of which could impact the findings. The study identified eight Cryptosporidium spp. in camels: C. parvum, C. andersoni, C. bovis, C. muris, C. ratti, C. occultus, C. ubiquitum, and C. hominis. The first three species had pooled prevalence rates of 65.5%, 66%, and 19.2%, respectively. Each of the remaining five species was documented using a single dataset/study. Moreover, genotypes IIdA19G1, IIaA15G1R1, If-like-A15G2, IIdA15G1, IIaA15G2R1, IIaA17G2R1, and IIaA18G2R1 (C. parvum), genotype IV (C. ratti), genotype XIIa (C. ubiquitum), and genotype IkA19G1 (C. hominis) have been identified in camels globally. The findings suggest that camels can act as a source of infection for a variety of Cryptosporidium species/genotypes, and can therefore play a key role in disseminating this protozoan to humans and animals.