A hospital-based serological survey of cryptosporidiosis in the Republic of Korea

Abstract

The seroprevalence of cryptosporidiosis was examined using patients' sera collected from hospitals located in 4 different areas of the Republic of Korea. ELISA was used to measure antibody titers against Cryptosporidium parvum antigens from a total of 2,394 serum samples, which were collected randomly from patients in local hospitals; 1) Chungbuk National University Hospital, 2) Konkuk University Hospital, 3) local hospitals in Chuncheon, Gangwon-do (province), 4) Jeonnam National University Hospital, from 2002 through 2003. Of the 2,394 samples assayed, 34%, 26%, and 56% were positive for C. parvum-specific IgG, IgM, and IgA antibodies, respectively. Positive IgG titers were most common in sera from Jeonnam National University Hospital, Gwangju, Jeollanam-do, and positive IgM titers were most common in sera from Chungbuk National University Hospital, Cheongju, Chuncheongbuk-do. The seropositivity was positively correlated with age for both the IgG and IgA antibodies but was negatively correlated with age for the IgM antibodies. Western blotting revealed that 92%, 83%, and 77% of sera positive for IgG, IgM, and IgA ELISA reacted with 27-kDa antigens, respectively. These results suggested that infection with Cryptosporidium in hospital patients occurs more commonly than previously reported in the Republic of Korea.

Keywords: Cryptosporidium parvum; ELISA; cryptosporidiosis; seroprevalence; western blot.

Fig. 1

Map showing the 4 surveyed areas (•) in the Republic of Korea. CNUH, Chungbuk National University Hospital, Cheongju, Chungcheongbuk-do (province); KUH, Konkuk University Hospital, Chungju, Chungcheongbuk-do; CC, local hospitals in Chuncheon, Gangwon-do; JNUH, Jeonnam National University Hospital, Gwangju, Jeollanam-do.

Fig. 2

Results of ELISA for Cryptosporidium parvum specific IgG, IgM, and IgA antibodies in 2,394 serum samples collected from 4 different localities in the Republic of Korea. (A) IgG; (B) IgM; (C) IgA. CNUH, Chungbuk National University Hospital (Cheongju); KUH, Konkuk University Hospital (Chungju); CC, Local hospitals in Chuncheon; JNUH, Jeonnam National University Hospital (Gwangju); N, Negative control. Horizontal bars represent the mean cut-off for IgG, IgM, and IgA levels. Numbers are shown as mean OD ± standard deviation.

Fig. 3

Age distribution of Cryptosporidium parvum-positive sera examined by ELISA. (A) Age-prevalence of IgG, IgM, and IgA antibodies against C. parvum. Data are shown as mean and standard deviation values. A total of 2,134 serum samples were examined for IgG and IgM antibodies, and 751 were examined for the IgA antibodies. (B) Prevalence of positive sera having IgG, IgM and IgA antibodies together, by age.