Cryptosporidium is a protozoal infection which is a cause of diarrhea in children and immunocompromised patients throughout the world. In human, infection with Cryptosporidium can result in severe diarrhea, which is usually self limiting in immunocompetent individuals, but may be chronic and life threatening in immunocompromised.
In developing countries, diarrhea caused by Cryptosporidium early in childhood may be associated with subsequent impaired physical and cognitive development. Currently 18 Cryptosporidium species have been recognized but C.parvum and C. hominis are the species predominantly found in human.
Diagnosis of cryptosporidiosis is generally based on microscopic detection of oocysts in stool, but this offers no information about the infecting species. The development of genetic tools has made possible detection of Cryptosporidium oocysts by PCR, which can differentiate between human and bovine genotypes of Cryptosporidium, which is helpful in epidemiological investigations and in detection the source of infection.
The aim of the present study is to detect genotypes of Cryptosporidium isolates obtained from diarrheic children in Qauliobyia Governorate.
In our study diarrheic stool samples of 430 children were examined by microscopic stool examination, and all samples included in this study were subjected to parasitological examination for detection of Cryptosporidium oocyst or other parasites, using direct wet mount smear, Sheather's sugar cover slip flotation method, formol-ether concentration technique, and MZN stain, then genotyping of 50 Cryptosporidium positive samples was done by nested PCR technique.
Our results showed that:
- Among the whole 430 diarrheic children included in this study there were 48 Cryptosporidium positive cases (11.2%) detected by MZN after concentration with Sheatherꞌs sugar flotation method while there were 50 positive cases (11.6%) detected by MZN after concentration with formol ether concentration method.
- Cryptosporidium genotyping was performed for 50 Cryptosporidium positive samples by nested PCR and restriction fragments length polymorphism (RFLP) followed by sequencing of the TRAP- C2 gene from oocysts in stool samples, and showed that, the majority of Cryptosporidium positive cases were due to C. parvum, as there were 41 cases (82%),while C. hominis comprised only 6 cases (12%) and there were 3 cases (6%) having both genotypes of Cryptosporidium.
- C. parvum was more common among children with age group from 2-5 years, as there were 15 cases (36.6%) followed by children less than 2 years, as there were 14 cases (34.2%) while there were 12 cases (29.3%) with age group 6-14 years. While C.hominis was more common among children with age group less than 2 years, as there were 5 cases (83.3%) followed by children with age group from 2-5, as there was one case (16.7 %), while there was not any case with age group (6-14 years), and this difference in age distribution among Cryptosporidium genotypes, was statistically insignificant.
- C. parvum was more common among males, as there were 25 cases (61.0%), while among females there were 16 cases (39.0%) but this difference was statistically insignificant. While C.hominis was more common among females, as there were 5 cases (83.3%), while among males there was one case (16.7%) and this difference was statistically significant.
- It was found that higher rate of C. parvum infection was in cases from rural areas, as there were 26 cases (63.4%) than those from urban areas, as there were 15 cases (36.6%) and this difference was statistically significant. While in C. hominis higher rate of infection was in cases from urban areas as there were 4 cases (66.7%) than those from rural areas as there were 2 cases (33.3%) but this difference was statistically insignificant.
- Among C. parvum genotype there were 29 cases (70.7%) presented with abdominal pain, 24 cases (58.5%) presented with vomiting and 16 cases (39%) presented with fever. Among C. hominis genotype there were 3 cases (50%) presented with abdominal pain, one case (16.7%) presented with vomiting, and 4 cases (66.7%) presented with fever, the variation in clinical manifestations among Cryptosporidium genotypes was statistically insignificant.
- Among C.parvum genotype there were 30 cases (73.2%) immunocompromised and 11 cases (26.8%) immunocompetent and this difference was statistically highly significant, while among C.hominis genotype there were 3 cases (50%) immunocompromised and 3 cases (50%) immunocompetent, so there was no statistically significant difference.
- Among C.parvum genotype there was a peak in summer as there were 21 cases (51.2%), followed by spring as there were 18 cases (43.9%), but in winter there was one case (2.4%), and in autumn there was one case (2.4%). Also among C.hominis genotype there was a peak in summer as there were 4 cases (66.7%), and in winter there was one case (16.7%), and in spring there was one case (16.7%), but there was not any case detected in autumn, and this difference was statistically highly significant.
- Cryptosporidiosis was found to be more prevalent among age group below 2 years, as there were 21 cases (42%), followed by children with age group 2-5 years, as there were16 cases (32%), but among children with age group 6-14 years there were 13 cases (26%).This difference was statistically highly significant.
- Cryptosporidium infection is insignificantly more prevalent among males than females as it was detected among 27 males (54%) and among 23 females (46%). This difference was statistically insignificant.
- Higher rate of infection was detected in cases from rural areas, as there were 29 cases (58%) than those from urban areas, as there were 21 cases (42%) and this difference was statistically insignificant.
- The main presenting symptoms of cryptosporidiosis in addition to diarrhea were abdominal pain, as there were 33 cases (12.1%), followed by vomiting, as there were 26 cases (11.6%) and there were 20 cases (10.5%) presented with fever.
- It was found that, there were 23 cases (46%) presented with severe diarrhea, 15 cases (30%) presented with moderate diarrhea, and 12 cases (24%) presented with mild diarrhea. This difference was statistically significant.
- It was found that, there were 27 cases (54%) presented with duration of diarrhea lasting less than 7 days, 14 cases (28%) presented with duration of diarrhea lasting from 7-14 days, and 9 cases (18%) presented with duration of diarrhea more than 21 days, this difference was statistically insignificant.
- Breast feeding in the first two years of life has a protective effect against infection with Cryptosporidium.Consumption of contaminated food and water by artificially fed children brought them to be susceptible to infection. It was noticed that, the infection rate was higher in artificially fed children as there were 13 cases (61.9%) than in breast fed children, as there were 8 cases (38.1%), but this difference was statistically insignificant.
- The rate of Cryptosporidium infection was higher in children having tape water supply as there 41 cases (82%), than those having underground water supply as there were 9 cases (18%), this suggesting the possibility of contaminated tape water and this difference was statistically highly significant.
- As regard contact with animal and Cryptosporidium infection there were 32 positive cases (64%) gave history of animal contact, and 18 cases (36%) with no history of animal contact and this difference was statistically significant.
- Higher rate of Cryptosporidium infection was observed in immunocompromised children, as there were 35 cases (70%) than in immunocompetent children, as there were 15 cases (30%) and this difference was statistically highly significant.
- The highest number of Cryptosporidium infected children was observed in summer, as there were 25 cases (50%), followed by spring, as there were 20 cases (40%), in autumn there were 3 cases (6%), and in winter there were 2 cases (4%), and this difference was statistically highly significant.
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