Detection and molecular characterization of Cryptosporidium spp. in dairy calves from the Valdivia province, Chile

Objective. Detect acid-fast oocysts of Cryptosporidium spp. using the Ziehl-Neelsen stain (ZN) and apply molecular tools with the 18S rARN (18S rARN) and 60 kDa glycoprotein (gp60) genes to characterize the species and subtypes present in Valdivia province. Material and methods. 275 samples of calves from 15 dairy farms from the Valdivia province were analyzed by ZN stain. Samples that showed positive results to ZN were then submitted to PCR processing aiming as target the 18S rARN and gp60 genes, with subsequent sequencing of the latter. Results. 30 samples were positive to ZN, of which 46.6% (14/30) were confirmed by PCR amplification for 18S rARN and from those, 42.8% (6/14) also amplified the gp60 target using PCR. Posterior sequencing of this gene showed the presence of C. parvum in 100% of the isolates and the subtypes IIaA15G2R1 (3/6), IIaA14G1R1 (2/6) and IIaA17G1R1 (1/6). Conclusions. Subtype IIaA15G2R1 was predominant, being found within two communes of the province. The subtype IIaA14G1R1 was found in two farms belonging to the same commune and to our knowledge represents the first time this subtype has ever been reported in cattle in Chile and the continent. Finally, subtype IIaA17G2R1 has been found sporadically in calves just like in the present study. Furthermore, all three variants have already been reported infecting humans, however during the development of this study, we found no other records of studies that aimed the characterization of the subtypes of C. parvum from calves raising systems and workers, to have ever been conducted in Chile. Therefore, it is important to promote further investigation on this subject.