Molecular typing of Cryptosporidium spp. circulating across multiple sources in a Latin American country

Cryptosporidium is an intestinal protozoan causing diarrheal disease in humans and non-human animals, with severe and chronic disease primarily affecting young and immunosuppressed individuals. Among the general population, C. parvum (zoonotic) and C. hominis (anthroponotic) are the two main species involved in food- and waterborne outbreaks. In a local survey, we reported a high prevalence of Cryptosporidium spp. among asymptomatic carriers and their pets (24% and 54%, respectively). To understand the transmission patterns of the infection, we molecularly characterized Cryptosporidium isolates from humans, pets, raw vegetables, and cattle in our region. Positive samples from different sources were subjected to DNA extraction. Humans and pets tested positive by PCR, while cattle and vegetables were positive by both microscopy and PCR. Cryptosporidium species identification and genotyping were performed using nested PCR targeting the 18S rRNA and gp60 genes, respectively, and Sanger sequences were analyzed with Cryptogenotyper1.5. Phylogenetic trees (maximum-likelihood) and haplotype analyses were conducted. Sixty-one isolates (61/87) were identified: 60C. parvum and 1C. bovis. Nucleotide diversity varied slightly across populations (pets > humans > cattle > vegetables). Fifteen (25%) C. parvum isolates were genotyped, including 10 from calves (IIaA17G2R1), 3 from humans (2 IIaA17G2R1, 1 IIaA16G2R1), and 2 from raw vegetables (1 IIaA17G2R1, 1 IIaA12R1). The predominance of C. parvum and the detection of subtype IIaA17G2R1 across multiple hosts may be consistent with a zoonotic transmission pattern. A C. parvum IIaA12 variant was first detected, expanding the known diversity of C. parvum.