Pcr amplification by two different primers for early diagnosis of schistosoma mansoni infected snails

The traditional methods for detection of snail infections cannot differentiate between animals and human Schistosoma and cannot detect early infection so the need for PCR is obligatory. In the present study, two types of primers for conventional PCR were used and compare between them and other traditional methods (shedding, crushing) in attempt to apply this technique in the field for early diagnosis of Schistosoma infection as a trial for better control and prevention of the disease. To fulfil this aim in our study we use two main groups of snails the laboratory groups (L) and the environmental groups (E) collected from water canal in Dakhalia and Sharkiya governorate. All laboratory groups are examined by PCR by using two different primers (121bp, 247bp). All environmental snails are examined for infection by shedding, crushing methods then PCR amplification by two different primers (121bp, 247bp). for detection of infection and the obtained results are compared. DNA was extracted from laboratory infected snails in addition to non infected (as negative control) and subjected to PCR using121 bp primers and 247 bp primers which specific to a partial sequence of S. Mansoni aldolase. The percentage of detection of infection in the laboratory snail were 53,3%, 66,6%, and 73.3%by using of 121bp primer at the 1st, 5rd, and 8thday of infection respectively, however the detection were 86.6%,73.3% and100% by using of 247bp primers. Regarding the environmental snails,on comparing the sensitivity and specificity of crushing method in relation to PCR amplification using 247bp primer in Sharkiya, were found to be 36.3%, 100% respectively while in Dakhalia were found to be 28.5%,100% .the average sensitivity of PCR amplification by 121bp compared to PCR amplification by 247bp was 63.3%. In conclusion, PCR is superior to the conventional methods and can detect positive cases that were negative when examined by shedding or crushing methods. 247bp primer are more specific than 121bp primer for detection of infection in S. Mansoni infected snail and can detect early snail infection and this help control of the disease.