Microscopic and molecular investigation of Cryptosporidium spp. in sheep in Nineveh governorate, Iraq

The research aimed to investigate Cryptosporidium spp. that infect sheep (different ages) by gathering 200 fecal samples from sheep in various regions of Nineveh province during the period from August 2024 to the end of February 2025.All samples were Examined by Microscopic methods and PCR technique followed by DNA sequencing tests and phylogenetic tree analysis to identify the species of parasite, which were then entered into the NCBI-GenBank database. This study was conducted for the first time in Nineveh province for identify Cryptosporidium species in sheep through PCR analysis were recorded in NCBI-GenBank database under accession numbers. The microscopic examination by using Modified Ziehl-Neelsen stain (MZN), showed that the total infection rate was 52 % (104/200), with the severity of infection with the Cryptosporidium spp. in sheep was 62.5%, while the percentage of mild infection in sheep was 37.5% of the total (104) examined samples. Three species of Cryptosporidium were identified in the results of DNA sequencing based the 18s rRNA gene. Which namely C. parvum, C. hominis, and C. ubiquitum, six strains were registered which received the registration number GenBank accession number. Furthermore, through analysing the genetic evolutionary tree of the isolated strains, confirmed the existence of a convergence between the isolated local strains and the rest of the strains recorded in the gene bank and isolated in other countries of the world.