Incidence of Cryptosporidium parvum in Patients with Diarrhea

Cryptosporidiurn parvirm may produce self-limited diarrhea in immunocompetent humans and even fatal forms of diarrhea in immunologically deficient patients (1-4). We studied the occurrence of the parasite C. parvum in 1165 stool specimens from patients with diarrhea, and investigated the relationship between the presence of C. parvum in the feces and the age of patients.The purpose of this study was to evaluate the occurrence of C. parvum as a potential pathogenic agent in patients with diarrhea, since no such data are yet available for Slovenia. MATERIALS AND METHODS. Between March 1, 1995 and the end of August 1995, 1165 stool samples were examined for C. parvum and other parasitic, bacterial and viral enteropathogens at the Institute of Microbiology and Immunology, Medical faculty, Ljubljana. The samples were obtained from patients ob both sexes and varying ages, who came from different parts of Slovenia. They all presented with watery diarrhea. All of them were considered immunocompetent; serologic tests for HIV infection were not done. Fecal specimens were collected before the administration of antibiotics. No significant differences were found between the patients in regard to their sex or the geographic area they came from. As we were interested in the occurrence of C. parvum in toddlers and primary schoolchildren, who more frequently come in contact with dirt but often do not wash their hands before meals, we examined fecal specimens from 563 children under 14 years of age (range 5 months to 14 years) and compared the results with those obtained from a group of 602 patients aged over 14 years (range to 90 years). Stool samples were examined for protozoa and helminths as direct wet mounts, as a iodine wet mount preparation and by permanent staining. The modified acid-fast staining (ZiehlNeelsen) was used for screening for C. parvum. Smears were prepared from aliquots of fecal sediment by the formalin-ethyl acetate concentration method and screened for the presence of organisms per high-power field (x 400 magnification), and per oil immersion field (x 1000) by bright field microscopy. The bacteriological evaluation included culturing for Salmonella, Shigella, Campylobacter, Staphyloccocus airreus, Yersinia enterocolitica, Escherichia coli, as well as for some organisms of questionable pathogenicity, such as Candida and Proteirs mirabilis. Clostridium dificile was looked for in 101 C. parvum positive patients. Rotavirus was identified by the ELISA procedure (Enzygnost Rotavirus-Ag monoclonal, Behring) and electron microscopy. Adenovirus as 40/41 were identified by ELISA (IDEA-Dako). The presence of caliciviruses, astroviruses and Norwalk viruses was determined by electron microscopy. Statistical analysis was done by the Chi-square test. RESULTS AND DISCUSSION. Samples from patients with C. parvum were found to be positive whether the formalin-ethyl acetate concentration technique was used or not. The main difference was an increase in the number of organisms observed. The age distribution of 563 patients aged 14 years or less and 602 patients older than 14 years is shown in Table 1. Of 1165 stool specimens obtained from patients with diarrhea, 101 (8.7%) were positive for C. parvum. In the younger group, 39 (6.9%) of the 563 patients were positive, while in the older group of 602 patients, 62 (10.3%) were C. parvum positive.