Co-infection with Cryptosporidium parvum and Cyclospora cayetanensis in immunocompromised patients

Forty nine stool specimens collected from severe diarrheic patients. Eight were suffering from Hodgkin's lymphoma, and the rest were suffering from acute lymph plastic leukaemia. All were examined microscopically for protozoan parasites mainly, Cryptosporidium parvum and Cyclospora cayetanensis. Of the patients, 34 (69.4%) were positive and 15 (30.6%) were negative by both microscopy and nested PCR. An additional 12 (24.5%) who were negative by microscopy were positive by nested PCR. Stool examination revealed 16 cases with C. parvum, and 6 with C. cayetanensis, and 3 cases showed mixed infection. The results were compared with the established nested PCR assay to detect DNA directly from stool specimens. The patients <3 years old more affected by Cryptosporidium infection, unlike Cyclospora sp. Infection was in older age groups, which reflected the modes of parasite' transmission.. Diarrheal illness was stronger for Cyclospora than for Cryptosporidium. After the extraction of DNA from stool, a 402-bp fragment of C. parvum, and 602 bp fragment of C. cayetanensis was amplified. The amplified products, 194-bp DNA fragment for C. parvum, and 306 bp DNA fragment of C. cayetanensis were used for the second run. This study indicated that primers were specific for DNA of C. parvum and C. cayetanensis. PCR detected a total of 22 (44.9%) positives for C. parvum infection (6 negative by AF stool examination), and 12 (24.5%) positives for C. cavetanensis. Infection (6 negative by AF stool examination), 7 (14.3%) showed mixed infection (4 negative by AF stool examination), all microscopic negative specimens were positive by successive stool examination. Microscopy exhibited sensitivity of 72.7% for C. parvum, 50% for C. cayetanensis and 100% specificity for both parasites compared to 100% sensitivity and specificity with PCR. So, PCR is more sensitive and easier to interpret but required more hands-on time to perform and is more expensive. However, PCR batch analysis reduces the cost considerably.