Multiple Cryptosporidium parvum subtypes detected in a unique isolate of a Chilean neonatal calf with diarrhea.

To further understand the composition of population of parasite in a single host, we analyzed the GP60 gene of Cryptosporidium parvum amplified from DNA of a randomly selected isolate found in the feces of a diarrheic calf from a dairy farm in Central Chile. Direct sequencing of the amplicon yield the IIaA17G4R1 C. parvum subtype. The same amplicon was cloned in Escherichia coli (22 clones) and sequenced, yielding three different GP60 subtypes, IIaA17G4R1 (16/22), IIaA16G4R1 (1/22), and IIaA15G4R1 (1/22), and four sequences with nucleotide substitutions in the serine repeats, which subtype would be otherwise IIaA17G4R1. It is thus possible to determine allelic polymorphism using Sanger sequencing with an additional step of bacterial cloning. The results also indicate the necessity to further characterize parasite populations in a single host to better understand the dynamics of Cryptosporidium epidemiology.