Experimental Hydatidosis,Sudan,Transmission,Natural Infection

The work presented in this thesis addressed four main aspects of studies dealing with experimental infections leading to the recovery of adult Echinococcus granulosus worms in the intestines of infected puppies, in- vitro studies involving the nature and biology of isolated protoscolices and intact cysts obtained from the lungs of infected camels and the biological studies of hydatid cysts. Furthermore recorded incident of hydatid cysts in the intermediate hosts were collected Oral experimental infection of puppies with hydatid cysts obtained from infected camels using isolated protoscolices, revealed adult Echinococcus granulosus. The worms were recovered from the small intestines. Higher numbers of worms were obtained in infections from lung hydatid cysts as compared with lower numbers obtained from liver cysts. More worms were collected from the upper parts of the intestines than the lower parts. Experimental feeding of puppies with hydatid cysts obtained from infected cattle, using isolated protoscolices, was not established. No worms were found in the intestines of dogs. However, modification of the infected procedure was used by feeding whole cysts obtained form the lungs and the livers of infected cattle resulted in the establishment of infection. Throughout the experimental work, the infection is established by the detection of eggs of Echinococcus granulosus worms in the faeces of the experimental puppies. Thus the Prepatent period, as evidenced by the time of the first appearance of eggs in the faeces of experimentalpuppies, ranged between 31-55 days. In- vitro studies were performed by observing the viability of isolated protoscolices or intact cysts placed in normal saline at room temperature and then in the fridge. At room temperature, 40% of the protoscolices remained active and viable for 4 days. Complete death occurred after 6 days; while 70% of those cysts placed in the fridge remained viable for 5 days and death occurred after 7 days. Death of all protoscolices occurred after 17 days, whenintact protoscolices inside hydatid cysts were placed inthe fridge. These were followed by in –vivo studies, to examine the infectivity of storage viable protoscolices experimentally in puppies, which yield a successful transmission. Samples of hydatid cysts were collected from slaughtered camels, cattle and sheep in different abattoirs of Khartoum State. No cysts from goats were recovered. The size of cysts, volume of cystic fluid and number of the protoscolices were recorded. Hydatid cysts from camels measured each 9.5 cm. for the maximum length of diameter and 1.3 for the minimum. The total volume of fluid, which was aspirated from the cyst, was 6 to 150 milliliters. Hydatid cysts from cattle were 0.5-10cm. The maximum volume of the fluid inside the cyst was 60 milliliters. The size ofthe hydatid cyst obtained from sheep ranged between 0.9 cm. to 3.0 cm. but the fluid was mostly too little to be measured. The biological status of the cysts was evaluated visually and microscopically as fertile, sterile, caseated, or calcified. Out of 149 cysts from camels, 96.4% were found to be fertile. As for cattle, out of 26 hydatidcysts examined only 23.1% were fertile. In case of sheep, hydatid cysts 91.7% were sterile. Official records obtained showed the presence of hydatid cysts in slaughtered camels, cattle, sheep and goats in Khartoum state during the period 1995-2008. The highest infection with the cysts occurred in camels followed by cattle and the lowest was found in sheep; however, goats showed no infection. Information sources regarding human hydatidosis showed, sixteen cases of patients, as intermediate hosts, were infected in Khartoum state during the period2000- 2009. The maximum size of the diameter of the cyst was 12 cm. and the minimum size was 2 cm. The ages of the patients involved, ranged between 6 and 55 years old