Summary :Trichinellosis has become undoubtedly worldwide in distribution. Its diagnosis relies largely on the serodiagnostic procedures which are of great value but unfortunately miss the enteric phase. This could be a serious diagnostic problem in the absence of corresponding epidemiological data and typical symptoms and signs of the disease. In this study the possibility of coproantigen detection, as an early diagnostic aid in trichinellosis, was investigated in mice experimentally infected with Trichinella spiralis.A modified double sandwich ELISA was developed using polyclonal antibodies raised in rabbits and guinea pigs against larval somatic antigens. The first detection of coproantigen was as early as the first day post infection, gradually increasing to reach its peak on the seventh day and then decreasing to disappear completely on the third week post infection. Another test, the coagglutination test (Co-A) was used, and this test confirmed the previous results. The finding of this study suggest that the coproantigen detection could be exploited to confirm ongoing early Trichinella spiralis infection. This fast and easy to use diagnostic method should improve the early infection in human.

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We aimed to induce conversion of RH-stain tachyzoites to bradyzoites by changing the pH of the culture medium. Alkalization of the medium to pH 8 induced morphological changes in the cultured tachyzoites. The majority of the organism increased in size and changed from a regular crescent shape to a rounded or ovoid shape. Cyst-like structures were formed. Using a computerized image analyser, significant differences in the size of the whole organisms and in their nuclei were observed compared to the control group. The converted organisms also showed significant differences from the control group by quantitative DNA analysis, and did not infect mice.