| With the improvement of people's living standards, convenience of traffic, and change of eating habits, all of these result in the rapidly increasing of food borne diseases and zoonosis in our country in recent years, one of them is the nematode, Angiostrongylus cantonensis. Since the 90's of 20th century, small-scale A. cantonensis outbreak in Beijing, Fuzhou, Wenzhou and other areas, especially in summer and autumn more than 200 cases of cases in Beijing in 2006, which caused public fear and attention of related aspects.This article introduced the current research situation of Angiostrongylus cantonensis, species of its intermediate host and current level of its diagnostic techniques. Aimed at the characteristics of snails infected by A. cantonensis from Guangzhou,Guangxi,Yunnan and Fuzhou, and other places, the specific detection methods were established, with PCR, real-time specificity of fluorescence PCR, those methods were efficient, such as in short time, high sensitivity, high specificity . The snail of intermediate host, Pomacea canadliculata, were carried for controling test with several drugs. The good diagnostic method for the test of A. cantonensis in fresh products, such as shellfish, etc., and proper diagnose methods of wild infected factor census, possesses vital importance in food safety, prevention and control of A. cantonensis and epidemic outbreaks. The results of this paper are showed follows:1. Species identification: In this research, universal primers XZ1, NC2 were used, the templates of DNA were extracted from the local species Angiostrongylus, those samples were collected from Guangxi, Guangzhou, Fuzhou and Shanghai, respectively, amplified ITS-2, by the optimization of temperature, primer concentration, and so forth, 250bp fragments were obtained, after sequencing verification, compared with the gene sequence of A. cantonensis in Genbank , the similarity was 99.5%, so judgment was made that all of the species stated above are A. cantonensis.2. In this study conventional PCR method was established first, in order to detect the A. cantonensis which parasitize in intermediate hosts, such as Pomacea canadliculata, Achatina fulica and Achatina fulica, ect. According to the gene sequence of A. cantonensis in Genbank, a pair of specific primers about A. cantonensis was designed, optimized reaction conditions of PCR, results showed that this method for detection effect of A. cantonensis from intermediate host had higher specificity , sensitivity and rapid than the method of tissue bomogenate,3. The detection methods of real-time fluorescence PCR were first successful applied with TaqMan probe for detection of snails infected with A. cantonensis , the TaqMan primers and probe were design by choosed the conservative regional ; the luminescence and quenching groups were marked, PCR reaction on the influence factors were optimized. The results indicated that the sensitivity of established fluorescent PCR method was much higher than that of conventional PCR method, and the excellences fluorescent PCR method were in short time, high sensitivity, specificity, etc..4. The effects of several drugs on the snail, Pomacea canadliculata were investigated. The snails were exposured in different concentration of 6% Meta, 6% crown Tatsu and a new medicine 12.5% chlorophthalic salicylaldehyde amine, and the mortality of the snails at 2d, 3d, 5d and 7d were recorded, then determined fatal effect of the drugs. The results showed that the effect of crown in 6% Meta and 12.5% chlorophthalic salicylaldehyde amine was much higher than 6% crown Tatsu in the same concentration molluscicide. It showed that chlorophthalic salicylaldehyde amine have a spacious application, But there certain degree of restriction in laboratory research, field trials are needed to further the identification... |
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