[Cryptosporidiosis in the Andean region of Colombia: seroprevalence and recognition of antigens].

The objective of this study was to investigate, for the first time, the seroprevalence of cryptosporidiosis among urban and rural inhabitants in several departments of the Andean region of Colombia. The antigen recognition of Cryptosporidium parvum was also studied with sera. Between June 1996 and October 1998 1,778 serum samples were collected from people selected through convenience sampling. The detection of anti-C. parvum antibodies (IgM, IgA, and IgG) was carried out with enzyme-linked immunosorbent assay, and antigen recognition was done with immunoblotting. A prevalence of 83.3% was found, and the antibody percentages were 72.2% for IgM, 27.7% for IgA, and 27.6% for IgG. Higher seropositivity percentages were found among women, persons less than 30 years old, and residents of rural areas. IgM seroprevalence decreased with age, while IgG and IgA seroprevalences increased with age. These three immunoglobulin isotypes most frequently recognized the antigens from 51 to 69 kDa, which can be considered immunodominant. Of note was the immunoreactivity of IgM and IgA to protein fractions from 12 to 14 kDa and from 42 to 48 kDa, respectively, which could indicate exposure to the parasite. These results indicate that cryptosporidiosis is endemic in the Andean region of Colombia, and that it is possible to attribute many cases of diarrheal syndrome to C. parvum.