Methods: We analyzed surveillance and laboratory records of cryptosporidiosis cases reported to Idaho Department of Health and Welfare during September 2012–August 2015. Available stool specimens from laboratory-confirmed cases were submitted to CDC’s CryptoNet for molecular testing using polymerase chain reaction-based restriction fragment length polymorphism analysis of the small ribosomal subunit RNA, and DNA sequencing of 60-kDa glycoprotein. We explored molecular profile of Cryptosporidium, and examined characteristics of sporadic cases by molecular profile.
Results: Among 429 reported cryptosporidiosis cases, ≥2 potential exposures were suspected in 134 (31%); transmission mode was indeterminate in 305 (71%). Among 38 stool specimens tested, we detected 2 subtype families (Ib and If) of C. hominis in 8 (21%), and 1 subtype family (IIa) of C. parvum in 30 (79%), of which subtype A16G3R1 was detected in 17 (57%) and was present in 9 of 12 outbreak-associated cases. In sporadic cases, persons with C. parvum (n = 20) and C. hominis (n = 6) had varying characteristics, respectively, as follows: female (70% and 83%), Hispanic (15% and 0%), illness onset in summer (50% and 33%), child care association (5% and 33%), and private well exposure (30% and 17%).
Conclusion: The cryptosporidiosis molecular profile in Idaho appears to be dominated by C. parvum. Increased molecular surveillance has potential to disentangle person-to-person, animal-to-person, waterborne, and foodborne Cryptosporidium transmission routes.
A. Bruesch, None
D. Roellig, None