The present study investigated the prevalence rate of Cryptosporidium parvum as a cause of diarrhea. We examined 942 stools of unidentified reasons occurring in patients in whom no immunosuppression had been detected. We examined the stools for Cryptosporidium parvum via modified acid-fast staining. The clinical records of all of the positive patients were then analyzed. Nine (1%) of the stools among the 942 diarrheal patients were positive for C. parvum. The positive rate in the males was 1.1% (6/522) and the positive rate of the females was 0.7% (3/420). Age distribution revealed that the highest positive rates were in patients in their sixties, with a positive rate of 2.5% (4/158). In the clinical tests, levels of c-reactive protein, erythrocyte sedimentation rates, and neutrophil proportions were normally increased in the peripheral blood, whereas the lymphocyte proportion exhibited a tendency towards decrease. The pathological findings were compatible with an inflammatory reaction in the host.
Adult ; Aged ; Animals ; Child, Preschool ; Cryptosporidiosis/*epidemiology/immunology ; *Cryptosporidium/isolation & purification ; Cryptosporidium parvum/isolation & purification ; Diarrhea/*epidemiology/immunology/parasitology ; Feces/parasitology ; Female ; HIV Seronegativity ; Humans ; Immunocompetence ; Korea/epidemiology ; Lymphocyte Count ; Male ; Middle Aged ; Prevalence ; Research Support, Non-U.S. Gov't ; Staining and Labeling

We observed the time gap between oocyst shedding and antibody responses in mice (3-week-old C57BL/6J females) infected with Cryptosporidium parvum. Oocyst shedding was verified by modified acid-fast staining. The individually collected mouse sera were assessed for C. parvum IgM and IgG antibodies by enzyme-linked immunosorbent assay from 5 to 25 weeks after infection. The results showed that C. parvum oocysts were shed from day 5 to 51 post-infection (PI). The IgM antibody titers to C. parvum peaked at week 5 PI, whereas the IgG antibody titers achieved maximum levels at week 25 PI. The results revealed that IgM responses to C. parvum infection occurred during the early stage of infection and overlapped with the oocyst shedding period, whereas IgG responses occurred during the late stage and was not correlated with oocyst shedding. Hence, IgM antibody detection may prove helpful for the diagnosis of acute cryptosporidiosis, and IgG antibody detection may prove effective for the detection of past infection and endemicity.
Animals ; Antibodies, Protozoan/*biosynthesis/blood ; Cryptosporidiosis/*immunology ; Cryptosporidium parvum/*immunology/isolation & purification ; Enzyme-Linked Immunosorbent Assay ; Feces/parasitology ; Female ; Immunocompromised Host ; Immunoglobulin G/biosynthesis/blood ; Immunoglobulin M/biosynthesis/blood ; Mice ; Mice, Inbred C57BL ; Oocysts/immunology ; Specific Pathogen-Free Organisms ; Time Factors