Acknowledgment:
The authors gratefully acknowledge Dr. Basma Hamed, a
veterinarian
working in the MERC, Mansoura, for her help in the handling of the
animals and experimenting. Also, the authors acknowledge Dr. Ahmed
Mohamed Yousof; Assistant Lecturer of Community Medicine, Faculty of
Medicine, Al- Alazhar University, for his help in the analysis of data
using the SPSS program.