Thesis (Ph.D.) - Cairo University - Faculty of Veterinary Medicine - Department of Animal Diseases

Twenty-eight broiler chicken farms from 16 to 70 days of age were examined clinically for suspected outbreaks of coccidiosis in eight governorates in Egypt. Flock history, clinical signs, dropping score and lesion score were recorded at time of examination. Fecal as well as intestinal samples (from different intestinal portions) were examined for coccidiosis using direct wet smear. Positive samples subjected to DNA extraction followed by amplification of internal transcribed spacer 1(ITS1) region of Eimeria genome with species specific primers of E. tenella, E. necatrix, E. maxima and E. acervulina for detection of these species using conventional PCR.The ITS1 region of ribosomal DNA (rDNA) from highly positive sample of single infection with E. tenella was sequenced and compared with sequence of ITS1 region of E. tenella strain in coccivac-B Vaccine. Results revealed that, the highest mortality rate (2.49%) was recorded in cobb breed in Dakahlia governorate while the lowest mortality (0.5%) was recorded in avian species in Dakahlia and Damitta governorate.Mean lesion score revealed that higher score in different types of chickens attributed to cecal portion 0.6-3.3 and lower score was observed in other portions 0-0.4 in duodenal portion, 0-0.9 in jejunal portion and 0-0.6 in illiual portion.PCR results revealed the prevalence of E. tenella 100% then E. necatrix 28.57 % from positive cecal and fecal samples, E. acervulina 21.42% from positive intestinal and fecal samples

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