Occurrence and Molecular Characterization of Cryptosporidium spp. in Swine Farms in Northeastern Spain

<i>Cryptosporidium</i> spp. are protozoan parasites that cause cryptosporidiosis, an enteric disease that can affect a wide range of vertebrate hosts. Pigs play a potential role in the transmission of <i>Cryptosporidium</i> spp. to humans, although infections are most often subclinical. This study aimed to assess the occurrence and molecular characterization of <i>Cryptosporidium</i> spp. in swine farms located in Aragón, northeastern Spain. Fecal samples (<i>n</i> = 72) were collected from 10 breeding farms, encompassing various production stages (lactation, nursery, fattening, and/or wean-to-finish). Data regarding the type of production system (two- or three-stage), production stages, and farming facilities (the type of flooring and water source) associated with the parasite presence were also analyzed using a questionnaire. The results showed that <i>Cryptosporidium</i> spp. were more frequently detected in fecal samples originating from three-stage production systems (21.9%) compared to two-stage systems (12.5%). Samples from the fattening stage exhibited the highest positivity rate and estimated oocyst count (3.0 oocyst/microscopic field). Furthermore, the molecular characterization of <i>Cryptosporidium</i> spp. revealed the circulation of multiple species both among farms and within the same pig production flow, with <i>Cryptosporidium scrofarum</i> being the most prevalent species (7/72; 9.7%), followed by <i>Cryptosporidium suis</i> (1/72; 1.4%). These findings underscore the importance of the surveillance and molecular characterization of <i>Cryptosporidium</i> spp. for controlling infections in pigs, considering the potential for the zoonotic transmission of this parasite to humans.