الفهرس 
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Abstract
Bovine cysticercosis is a zoonotic disease caused by the larval stage of the human tapeworm T. saginata. It is a notifiable disease to the World Organization for Animal Health. Infection of cattle with the larval stage is an important food safety issue and of economic concern in different areas of the world. Humans get infected by eating raw or undercooked meat containing viable cysticerci, and transmission to animals occurs upon contamination of food or water by feces of infected humans.
The present study aims to identify cysticercoid bovis cysts classified at the slaughterhouse and to determine the accuracy of this identification made by the classical methods of meat inspection. For confirmation as a step toward developing a more reliable method for the diagnosis of C. bovis in bovine tissues.
The current study was conducted in four abattoirs scattered all over EL-Beheira and Gharbia Governorates from May 2018 till the end of February 2019. A total of (n=687) slaughtered animals were examined in the abattoirs. Methods fordetecting cysts were visual inspection of carcasses, palpation and incisions of predilection sites: external masseter, tongue, heart, and diaphragm, also the internal pterygoid muscle and esophagus.
from all the examined bovine carcasses by macroscopic examination 50 suspected cysts were found from the different abattoirs. These cysts were found in the tongue, heart, masseter muscle and esophagus. All detected cysts weredivided into four parts; first part was placed into the freezer (-20°C) for molecular analysis, second part of cyst was preserved inbuffer formalin 10% for histopathological and immunohistochemistry studies and the thirdand fourth were preserved in 3% glutaraldehyde for study by Scanning (SEM) and Transmission (TEM) Electron Microscopy.
from the results of the present work, prevalence of C. bovis was 7.3% by visual examination compared to 1.9% as confirmed by PCR.
Using PCR, bands of the expected size (~599 bp) were found, most likely corresponding to T.saginata. Two representative sample were sequencedand the sequence data confirming cysticercus bovis.
Of687 slaughtered animals, 266 cattle and buffaloes were below two years with 4.9% infection rateas diagnosed by macroscopic examination, while the infection rate was 8.8% in (421 cattle and buffaloes)above two years. The difference was statistically significant between ages only in buffaloes.
Among cattle, a total of 156 slaughtered cattle were below two years with infection rate 3.2% with C. bovis diagnosed by PCR, while the infection rate was 2.9% from a total of 272 of cattle aged above two years.
When macroscopic examination was applied on a total of 687 slaughtered animals 429 cattle and buffaloes were males shown to be infected with rate of rate increased to 12% in female buffaloes only among 258.Statistically significant difference was found. All positive PCR results were collected from male cattle.
Regarding anatomical distribution and viability of suspected C. bovis in inspected organs of the slaughtered animals, a total 50 suspected collected cysts, two cysts were excised from the masseter, only one was viable, 18 cysts were collected from tongues, among them three were viable and 15 were non-viable; while 15 cysts were collected from heart tissues, onlyseven of themwereviable. As regards the esophagus, 15 suspected C. bovis were collected, only two of them were viable (13.3%). Thus totally 13 cysts, only were viable (26%) and 37 non-viable (74%).
However, the whole of positive cattle by visual examination for that 50 collected cyst was 18. On the other hand, diagnosis of that cysts by conventional PCR, 13 only were considered positive. They were all from cattle. Of11 (84.6%) were from the heart, one from the masseter and one from the tongue (7.7% each).As regards viability, among the 13 positive cyst, seven were viable (53.8%) and six were non-viable (46.2%)..
The distribution of the suspected C. bovis in various seasons,the highest infection of suspected C. bovis in animals was during summer (46%), in autumn (40%), followed by spring and winter (10% and 4%) respectively.
Regarding immunohistochemical staining technique of cysts confirmed positive by PCR, positive viable C. bovis showed specific background staining of caspase-3 reaction. Cellular reaction was also strongly stained as development of a brown reaction (n=5), while degenerated cysts showed nonspecific background staining of caspase-3 reaction and discoloration was apparent (n=8).
For the positive between PCR and immunohistochemical staining, the rate of viable C. bovis by PCR was 53.8% and by immunohistochemical staining was 38.5%. For degenerated C. bovis, the rate was higher in immunohistochemical staining.
As to, histopathological examination of cysts confirmed positive by PCR, positive viable C. bovis showed hemosiderin pigment, heavy chronic mononuclear inflammatory infiltrates of the surrounding tissues and multinucleated giant cells, while degenerated C. bovis cysts showed inflammatory infiltrates formed mainly of histiocytes, plasmacells and lymphocytes in between disrupted myocardial fibers. Calcified of C. bovis with central area of caseous necrosis and calcification.
Scanning Electron Microscopyultrastructure topography of positive C. bovis by PCR collected from slaughtered cattle illustrated outer tegument surface of the cyst of rough surface consisting of numerous sparsely situated microthriches with no apparent pattern of distribution. Forming something like a Network.
Transmission Electron Microscopy examination of C. bovis illustrated the distal cytoplasm with receding microthriches. Cytoplasm showing disk-shaped vascular structures and microthriches. The flame cells have marked cytoplasmic extensions in the longitudinal axis. Under the tegument, the subtegumental muscle bundles and extensions of the subtegumental cells with mitochondria and cytoplasm.