الفهرس 
Life Cycle of E. granuolosus
MATERIAL AND METHODOnly 14 pages are availabe for public view
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Abstract
Echinococcosis is a caused by adult or larval (metacestode) stage of cestodes belonging to the genus Echinococcus and the family Taeniidae. Cystic echinococcosis (CE) of animals and man cause severe economic loss and public health problem to both human beings and livestock.
The present study was carried out to assess ocular instillation of crude hydatid cyst fluid antigen as a screening tool for CE infection in livestock. The study comprised the following four objectives:
5. To assess ocular instillation of a crude hydatid cyst fluid antigen, from different animal species, as a screening tool for diagnosis of animal CE infection.
6. To study the frequency of infection with CE among slaughtered animals in Alexandria and Kom Hamada abattoir.
7. To study cross-reaction between hydatid cyst antigen and other tissue cysts.
8. To determine some animal characteristics associated with CE infection.
A cross sectional approach was used in the implementation of the present work. The study was conducted on 379 of different animal species (107 camels, 100 sheep, 12 goats, 62 cows and 98 buffalos) attended Kom Hamada, Damanhour and Automated Amerya abattoirs to estimate the frequency of hydatidosis among slaughtered animals during the period from April 2007 to June 2010.
The crude hydatid cyst fluid antigens were prepared from three different animal sources, camels (crude CHF-Ag), sheep (crude SHF-Ag) and buffalos (crude BHF-Ag). The crude hydatid cyst fluid antigen was prepared according to (Schantz and Kagan 1980) with total protein content 100 µg/ ml.
The ocular instillation technique of crude hydatid cyst fluid antigen was used for the diagnosis of CE infection among the slaughtered animals:
d- A subsample of 294 animals (72 camels, 70 sheep, 12 goats, 52 cows and 88 buffalos) were examined by crude CHF-Ag.
e- A subsample of 53 animals (18 camels, 15 sheep, 10 cows and 10 buffalos) were examined by crude BHF-Ag.
f- A subsample of 32 animals (17 camels and 15 sheep) were examined by crude SHF-Ag.
The animal data were recorded in a predesigned sheet included animal species, age, sex, country of origin, abattoir and the name of owner. Each animal subjected to premortem examination by veterinarians to determine age, sex and if there any pathological signs and symptoms as weakness, oedema of mucosa, emaciation etc. and post mortem examination after slaughtering to assess the general conditions of the carcasses, the location of the hydatid cyst in the different organs and any other infections found were recorded in the data sheet. The hydatid cysts were taken to the laboratory and confirmation of the diagnosis was made by:
a) Microscopic examination to detect hydatid sand and daughter cysts.
b) A DROP of the centrifuged hydatid cyst fluid was placed between two glass slides. The two slides were rubbed back and forth against each other. The grating of the hooks on the glass was felt and heard.
c) Histological examination: to see the acellular laminated layer using Periodic acid-Schiff method.
The results of the present study are summarized as follows:
1. The highest percentage of CE infection was recorded in camels (27.1%) followed by sheep (2%). No CE infection was detected among examined goats, cows and buffalos.
2. Amongst four imported camels form Sudan, three had CE (75%) and 25.2% of local camels had CE infection.
3. All infected sheep were female (3.8%), while males were free from infection, and all the examined camels in this study were male and had 27.1% infection rate.
4. The higher percentage of infection was observed among older age groups for both camels (29.5%) and sheep (3.8%).
5. Most of hydatid cysts in infected camels (89.6 %) were located in the lungs and the two infected sheep had lung cysts.
6. Most of the detected hydatid cysts were measured 1-5 cm (67.7%) and not calcified (93.5%), while nearly equal percentage was detected between cases which had a single or multiple cysts (51.6% had a single cyst and 48.4% had multiple cysts).
7. Crude CHF-Ag was the more sensitive to diagnose CE infection with sensitivity (61.9%), specificity (97.4%), PPV (65%) and NPV (97.1%). On the other hand least sensitivity was obtained with crude BHF-Ag when used; the sensitivity was (33.3%), specificity (98.0%), PPV (50%) and NPV (96.1%).
8. Crude SHF-Ag among camels had a sensitivity (50%), specificity (100%). PPV (100%) and NPV (78.6%). While among sheep only one CE case was detected and gave positive eye reaction.
9. Crude CHF-Ag among camels had a sensitivity (60%), specificity (92.3%) PPV (75%) and NPV (85.7%). While among sheep it had a sensitivity (100%) specificity (98.6%), PPV (50%) and NPV (100%).
10. Crude BHF-Ag among camels had a sensitivity (33.3%) and specificity (100%), PPV (100%) and NPV (88.2%).
11. Single cyst with positive eye reaction (62.5%); non-calcified cysts with positive eye reaction (58.6%). The small cyst with diameter < 1cm associated with positive eye reaction was (83.3%).
12. Among the examined buffalos one case of fascioliasis, one case of tuberculosis and one case of sarcosporidiosis were reported, while among cows two cysticercosis cases were reported.
13. Crude CHF-Ag had a cross reaction with (50%) of cysticercosis cases detected among cows.
from the results of the present study, it can be concluded that:
1) The camels (27.1%) followed by sheep (2%) were the most important intermediate hosts for Echinococcus granulosus infection in Egypt. The imported camels from Sudan had a high infection rate (75%), and the predominant infection site was the lungs (89.6 %).
2) The ocular instillation of crude antigen (specially CHF-Ag) in the present study had a sensitivity (61.9%) and specificity (97.4%), as compared with other immunological tests which used a crude antigen, it was obvious that the ocular instillation was more sensitive than intradermal test (using crude SHF-Ag) which gave positive result in (32.5%) of infected sheep, and enzyme-linked immunosorbent assay (ELISA) (using crude CHF-Ag) which had a lower sensitivity (21.92%) but with the similar specificity (96.94%) among different animal species; while it seems like indirect hemagglutination test (using commercial Echino-Kits) gave sensitivities of (45%) among camels and (81%) among both sheep and goats. On the other hand the current results less sensitive than ELISA (using native AgB) which gave the highest sensitivity (97%) for camel CE infection and specificity (90%).
3) Like other immunodiagnostic test used crude antigen, ocular instillation test had a cross reaction with other cestode infections as cysticercosis.
4) Finally, one can concluded that the ocular instillation test used on the present study is cheap, easy to prepare, easy to perform, rapid, reliable and highly cost-effective tool for field screening of CE infection.