Echinococcus Granulosus of Camel Origin: Experimental Infection and Immunodiagnosis in Dogs

Abstract

The present study was designed to experimentally study the development and infectivity of Echinococcus granulosus of camel origin in the definitive host the dog in the area of Tambool, Butana Province, Sudan. Also to evaluate the potentiality of immunological technique,Enzyme linked immunosorbant assay (ELISA) in the diagnosis of echinococcosis in the definitive host. The development of E granulosus of camel origin was studied in seven dogs experimentally infected with protoscolices originating from hydatid cysts isolated from camels (Camelusdromedarius). Dogs were necropsized 15, 21, 28, and 35 days post-infection (p.i.); all dogs had a low worm burden (12-37 worms). At day 35 p.i., majority of the parasites had developed three segments, while the embryophore of egg was not detected and the oncosphere was not completed. The results of post mortem examination for sixteen dogs shot by the police in Tambool town, showed that 5 dogs were found harboring E. granulosus adult worms. From these dogs, 8 were found infected with Taenia hydatigena. Mixed- infection with E. granulosus and T. hydatigena was observed in only one dog. When tested by ELISA out of these 16 Sera, 7 were found positive. Four out of five dogs which were positive at postmortem were positive at ELISA test. Only one dog which was found positive at postmortem was found negative by ELISA. Two dogs negative for E. granulosus and positive for T. hydatigena were found positive by ELISA test. One dog negative at postmortem for both, E. granulosus and T. hydatigena was positive of ELISA. Sera collected from dogs experimentally infected with E. granulosus were negative for ELISA until the last week of the experiment (35 days post infection). Although the readings of sera from experimentally infected dogs were below the cutoff point, we have observed that the antibody titre of the samples was slightly increasing during experiment. The results suggested that the use of ELISA in the diagnosis of canine echinococcosis could be used successfully in epidemiological surveys of echinococcosis in Sudan. The detection of E. granulosus in dogs at Tambool area was found 25% (5 out of 20 dogs were found harboring adult worms at postmortem). The high prevalence reported in dogs is an indication of hazard to human in this area. A mass dog eradication programme with a mass drug treatment programme of house dogs, coordinated with an educational campaign, could be effective to control the disease if implemented in this area.