الفهرس 
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Abstract
Current evidence indicates that pre-school children living in S. mansoni endemic
areas are at the same risk of schistosomiasis infection and morbidity as their school aged
siblings. Realizing this fact, the World Health Organization (WHO) including this age
group in highly endemic areas in control programmes using mass drug administration.
Nevertheless, detailed epidemiological information on S. mansoni infection among PSC is
lacking for many endemic areas, particularly in Egypt. This study was proceeded to
determine the intestinal schistosomiasis among pre-school and school aged children and
compare the efficacy of praziquantel treatment on the infected cases of both groups. The
used diagnostic tests including stool examination by Kato/Katz technique and real time
polymerase chain reaction based on SYBR Green.
This study was conducted in Bab EI Abid, Abis 8 village, Alexandria governorate.
After obtaining the consent of children’s parents and school guardians, a total of 400
children, 103 preschool children (1-5years age) and 297school children (≥6-12 years) were
selected randomly and asked to submit stool samples. All the stool samples were examined
microscopically after Kato- Katz technique. 120 stool samples negative after KAato Katz
were randomly collected from both groups (38 from PSC, 82 from primary school
children).Each fecal specimen was stored at -20oC for processing by real time PCR.
All positive cases were treated by single dose of PZQ (40mg/kgm body weight),
PZQ pills were crushed and oraly administered for PSC after mixing with water).The cure
rate was assessed by Kato Katz multiple (10 slides/each sample) four weeks after treatment
and real time PCR.
Among the studied cases, parasitologic examination of feces when using Kato- Katz
revealed that the prevalence of S. mansoni was 7.8%, 7.4% among PSC and school
children respectively.There was no statistical significant difference between the two
groups. 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 prevalence
between boys and girls which may be due to the change in female behavior. Regarding
infection intensity, the majority of children had light S. mansoni infection intensity
(63.3%) which may denote the availability of passive chemotherapy.
Regarding the negative cases after KK, real time PCR detected 25% S. mansoni
positive cases (15. 8% among PSC, 29.3% among school children).These results indicate
the low sensitivity of Kato- Katz as compared to the highest efficiency of real time PCR.
All positive cases treated with single dose of PZQ. The cure rate was estimated after both
KK and real time PCR. It was 100% by KK and real time PCR among PSC, indicating the
treatment effectiveness of PZQ. However, it was 91%, 77.2% by KK and PCR respectively
among school children. This denotes the ability of PCR for detection the positive cases
missed by KK.
Fair agreement between Kato- Katz and real time PCR in the diagnosis of S. mansoni
was observed.
The present work revealed that there is no significant difference between the
prevalence of S. mansoni among PSC and School children. The real time PCR diagnosed
significantly the missed cases after KK and post treatment.
Conclusion and recommendations
from the data of the current study, it could be concluded that:
S. mansoni constitutes a real public health problem among PSC and primary school
children in this study area.
This study highlights PSC as a potential transmission source of S.mansoni. The
neglecting of their treatment may lead to a potential source of transmission and
morbidity increase. New strategies for diagnosis and control should be adopted.
The single dose of crushed PZQ pills mixed with water succeeded to give 100% cure
rate among PSC as confirmed by KK and PCR.
The present study provides accurate diagnosis for positive cases and assessment of
cure rate by using real time PCR.
Real time PCR gave better estimation of S. mansoni as compared to Kato- Katz
particularly after treatment.
The present study humbly offers real time PCR as a test of choice for evaluation of
treatment and detection of hidden cases after Kato- Katz.
To detect low infection intensity and missed cases after Kato- Katz, it is
recommended to increase the cycle threshold during application of real time PCR to
40 cycles.
The two melting curves indicating some mutations which needs further study.