الفهرس 
cover englishOnly 14 pages are availabe for public view
 |  | from | 131 |  |  |
| | | from | 131 | | |
Abstract
Sucking insects, TseTse (Glossina sp.) is the main vector of Trypanosoma species and generates a significant economic impact on livestock. Trypanosoma evansi is mechanically transmitted in several ways. Soft tick species have also been suggested as vectors in the transmission of T. evansi. In the present study, during the period from April 2015 till March 2016, 970 cattle and 683 camels from Beni Suef, Giza and Red Sea Governorates were clinically examined for presence of ticks. Of the examined cattle, 495 (51%) were found infested by Rhipicephalus (Boophilus) annulatus ticks and of the examined camels, 265 (38.79%) were found infested by Hyalomma dromedarii ticks. Also, Ornithodoros savignyi were collected from camel pens at Shalateen City (Red Sea Governorate). Seasonal influence on the prevalence of ticks in camels and cattle was also studied revealing that the peak of tick infestation rate was during the period from June to November. Four hundred and thirteen (413) blood samples (201 blood samples from cattle and 212 from camels) were collected and examined for Trypanosoma infection by thin blood smear. The present work was initiated to estimate the role of O. savignyi ticks in experimental transmission of T. evansi to the laboratory animals. The collected T. evansi from naturally infected camels was propagated in pathogen free Swiss albino mice to be used in the experimental infection. Groups of pathogen free albino rats were inoculated with T. evansi to be used in experimental infection of Trypanosoma free O. savignyi ticks. The experimentally infected ticks were examined by light microscope, histopathology and polymerase chain reaction (PCR) for detection of T. evansi. Examination of gut of infected ticks by light microscope revealed that the number of parasite / field reached 12-17 parasites after 2 hours of feeding and decreased gradually till reached one parasite / field after 24 hours then disappeared after 48 hrs after feeding. Histopathological examination showed T. evansi between the cells of salivary gland after 28-30 days from feeding of O. savignyi ticks on infected rats. Analysis of PCR amplified fragments on agarose gel electrophoresis revealed that 227 bp was detected for T. evansi in salivary gland and whole body of O. savignyi ticks. Feeding of the experimentally T. evansi infected O. savignyi on free Trypanosoma rats showed negative results as no parasitaemia was detected in the rats up to 30 days after feeding. The study concluded that O. savignyi ticks can take T. evansi infection that remain for up to 30 days in its body but cannot experimentally transmit it to other laboratory animals.