الفهرس 
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Abstract
Schistosomiasis is one of the 17 neglected tropical diseases listed by the WHO that present substantial public health and economic burden. It is estimated that about 800 million people are at risk of infection, about 250 million are infected, of whom 120 million are symptomatic and 20 million have serious consequences, with 90% of the burden currently concentrated in Africa. Despite the continuity of implementing control measures, it remains one of several diseases that prevail in poverty conditions.
The Egyptian Ministry of Health and Population has announced the start of the campaign to confirm the final elimination of schistosomiasis by 2020, after achieving success in reducing the prevalence of schistosomiasis to about 0.2% by the end of 2016. However, there are still hot spot transmission foci. Kafr El-Sheikh is one of these high transmission areas. For optimal design of schistosomiasis control programs, it is essential to gain baseline information on the true prevalence. Accurate diagnosis is the key to adequate patient management and monitoring of the control measures.
The present study was designed to evaluate the performance of Loop-Mediated Isothermal Amplification for the detection of S. mansoni DNA from stool and urine samples in comparison with real-time PCR and microscopy.
The Loop-mediated isothermal amplification (LAMP) assay was described in 2002 as a rapid, sensitive, specific and time-efficient gene amplification technique that amplifies nucleic acids under isothermal conditions. Real-time PCR technique based on SYBR Green is used to identify S. mansoni DNA in faecal samples.
This study was conducted in Arab Elmahdar Primary School in Motobus village in Kafr El-Sheikh governorate. After obtaining the consent of school guardians and children’s parents, a total of 50 school children were invited to submit stool and urine samples. All the stool samples were examined microscopically after Kato-Katz technique. A part of each faecal specimen was stored at -20°C for further processing by real-time PCR. Urine samples were collected in screw-cap vials. They were stored at -20°C until the LAMP assays were performed.
Among the studied cases, parasitological examination of faeces when using Kato- Katz revealed that the overall percentage of helminthic infections was 44%. S. mansoni represented the highest infection rate as compared to other parasites (42% S. mansoni vs 2% (H. nana)). The highest infection rates of S. mansoni were detected in the age groups 9-10 and 12 years old. This may reflect the ignorance of the effective methods of prevention and possibly inappropriate application of treatment strategy.
Regarding gender, there was no significant difference in S. mansoni percentage between boys and girls which may be due to the change in female behavior and equal exposure to infection.
Despite the high prevalence, the majority of children had light S. mansoni infection intensity which may denote a low transmission potential.
The highest infection rate of S. mansoni in this study was detected by real-time PCR (44%), followed by Kato- Katz test (42%) and LAMP (36%) in the stool. All positive samples by LAMP were positive by both Kato Katz and real-time PCR. In urine samples, lower infection rates were obtained by real-time PCR and LAMP (24% and 14% respectively).
The agreement between Kato- Katz, LAMP and real-time PCR in the diagnosis of S. mansoni was fair to good agreement between the three techniques.
As regards the intensity of infection according to Kato- Katz, the discrepancies between the outcome of microscopy and the other two methods occurred only in children with no eggs detected or with light intensity of infection.
Real-time PCR gave better estimates for S. mansoni diagnosis in this study as compared to Kato- Katz and LAMP assay.
Lamp assay is a rapid test, easy to perform, and doesn’t need sophisticated equipment. Its high specificity and good performance in this study are promising for S. mansoni diagnosis and epidemiological studies of high and moderate-intensity areas. Further studies are needed regarding cost, classical DNA extraction procedures, cheap extraction kit, dried kit, and different primers. Also, urine samples need further optimization.