Summary
Cryptosporidium is an apicomplexan zoonotic protozoan parasite that infects many hosts including domestic animals, birds and human.
Cryptosporidiumis an obligate intracellular parasite that infects the epithelial lining of gastrointestinal and respiratory tracts. In immunocompetent individuals, the organism is localized in small intestine but in immunocompromised individuals, the parasite infects the gut, biliary and respiratory tracts.
Cryptosporidium is an important food-borne pathogen causing a disease of socioeconomic significance worldwide. It causes gastrointestinal disease in human.It is also waterborne parasites worldwide. Infection by Cryptosporidium occur through person-to-person contact, animal contact, ingestion of water or through food. The resistance of Cryptosporidium oocysts to disinfectants is high which enables them to survive for long periods and still remain infective.
Cryptosporidiosis mainly affects children with the most affected group is children from 1 to 9 years old. In developing countries, Cryptosporidium infection occur mostly in children younger than 5 years and 8-19% of diarrheal diseases are due Cryptosporidium infection.
There are different methods used in diagnosis of Cryptosporidium, including parasitological diagnosis by microscopical examination and staining method .Modified formalin-ethyl acetate (FEA) concentration method, modified zinc sulfate centrifugal flotation technique and sheather’s sugar flotation procedures can concentrate the oocysts. staining techniques include different types of stain such as Modified Zeil Neelsen and Giemsa stain. Immunological examination also can be used in diagnosis of Cryptosporidium by detecting antibody and antigen as direct fluorescent antibody (DFA) techniques, indirect immunofluorescence assay and enzyme-linked immunosorbent assay (ELISA) .
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The aim of this study was to evaluate nano-gold beads based-ELISA for detection of Cryptosporidiumantigen in stool samples of diarrheicpatients. For fillment of the study, two hundred stool samples were be collected from diarrheic patients attending Abo El Reesh hospital during the period from April 2015 to October 2015. Stool samples were collected after written informed consents obtained from all patients. Faecal samples were collected in clean and wide-mouthed covered containers. Parasitological examination of the collected samples by:direct wet smear, Merthiolate-iodine-formaldhyde concentration technique (M.I.Fc) and Modified Ziehl-Neelsen stain (M.Z.N). Imunological examinationby sandwich ELISA and nano-sandwich ELISA.
Among the whole 200 diarrheic stool samples included in this study there were 5 stool samples positive for Cryptosporidium (2.5%) detected by M.I.F. There were 47stool samples positive for Cryptosporidium detected by M.Z.N (23.5%).
It was found that children up to 1 year of life showed the highest rate of Cryptosporidium infection (41%) followed by the age group of (1 year to 5 years) at a rate of (23.5%) then lowest rate of infection (11% and 18%) were among those of (6-10y) and (more than 10y) years of age respectively, with a highly significant difference between the rate of infection and the age groups.
It was found that Cryptosporidium was common in females (27.9% ) than males (20.2% ).but there is no significant difference between males and females.
Cryptosporidium was common in rural areas (25 %) than urban areas (21.5%), this difference was statistically insignificant.Cryptosporidium was common with patients with animal contact (31.3%) but this difference was statistically insignificant.
It was found that Cryptosporidium was common in soft stoolwith prevalence rate (29%) then in loose stoolwith prevalence rate (27.1%)then in watery stool with prevalence rate (18.5%).
There were 25 cases (53.2%) presented with diarrhea more than five times per day, 15 cases (31.9%) presented with five times diarrhea per day, and 7 cases (14.9 %) presented with four times per day diarrhea. This difference was statistically significant.
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 and this difference was statistically highly significant.
There were 78 stool samples positive for Cryptosporidium (39%) detected by sandwich ELISAand 89 stool samples positive for Cryptosporidium (44%) detected by nano sandwich ELISA. This mean that nano sandwich ELISA improve the positivity of sandwich ELISA.
The sensitivity of sandwich ELISA and Nano-ELISA for detection of Cryptosporidium antigen in human stool samples were 68% and 85% respectively. The specificity of sandwich ELISA was 77.3%but nano-ELISA was 73.4%. This mean that nano sandwich ELISA improve the sensitivity of sandwich ELISA.
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