Collection of pre-encysted larvae of Trichinella spiralis

Objective To explore the collection time and method of the pre-encysted larvae of Trichinella spiralis. Methods Twenty adult rats were inoculated with 3 000 encysted larva of Trichinella spir-alis per rat by the oral route. At the 14th, 15th, 16th, 17th, 18th, 19th, 20th day after infection, the rats were killed and the muscles were digested with pepsin to collect Trichinella spiralis. Results At the 14th,15th, 16th day after infection, no Trichinella spiralis was found in diaphragm. At the 17th, 18th, 19th, 20th day after infection, Trichinella spiralis could be seen in the diaphragm and the number of Trichinella spiralis in-creased with time passing. At the 14th, 15th, 16th day, no Trichinella spiralis was obtained. At the 17th,18th, 19th, 20th day, the mean number of Trichinella spirulis collected were 5000, 8000, 10000, 30000per rat respectively. Conclusion The 20th day after Trichinella spiralis infection is the best time to collect the pre-encysted larvae of Trichinella spiralis. Pepsin digestion of muscles can be the choice of methods for col-lecting the pre-encysted larvae of Trichinella spirulis. Key words: Trichinella spiralis; Pre-encysted larva; Collection methods