Serological evidence of Cryptosporidium infections in a Russian city and evaluation of risk factors for infections

Purpose Assess the relative frequency of Cryptosporidium infections and risk factors for infection in Cherepovets, Russia. Methods In June 1999, data on demographic, socioeconomic, hygienic characteristics, and recent gastrointestinal illness were collected on 50 community-recruited adults and 50 blood donors. The community group then maintained daily diaries of exposures and gastrointestinal symptoms for 5 months. Sera samples at the inception and conclusion of the study were tested for antibody responses to the 15/17 kDa and 27 kDa Cryptosporidium antigens using mini-immunoblots. Results At the inception, 68% and 88% of study participants had detectable serological responses to 15/17 kDa and 27 kDa antigens. Older age was associated with stronger antibody responses to both antigens. Attendance at swimming pools was associated with stronger responses to both antigens in predominantly male blood donors. Over the follow-up period, drinking non-boiled water from shallow draw-wells was associated with an increase in serological response to the 27 kDa antigen. Self-reported gastrointestinal illness was not associated with an increase in serological response. Conclusions The prevalence of positive serological responses in Cherepovets was higher than in most prior Cryptosporidium serosurveys in non-outbreak communities. Drinking water is an important pathway for infection.