ABSTRACT
Objective To observe the development of Schistosoma japonicum after single sexual infection and double sexual infection respectively. Methods A single Oncomelania hupensis snail was infected by a single schistosome miracidium. The lar?va were induced and released from the snail after 60?day incubation at 26℃. The mice were infected by the larva(single sexual infection)and dissected 40 days after the infection. All the worms were collected and the sex of the larvae was determined by the sex of the adult worms. Then,the mice and rabbits were infected by single sex of larvae(single sexual infection)and double sex of larvae(double sexual infection)respectively. The mice and the rabbits were dissected 40 days after the infection. All the worms were collected and measured under a microscope. Results All the male or female worms were collected from the mice and rabbits after single sexual infection. There were three main forms of worms after dissection of double sexual infection of mice and rabbits:folded mature male and female,male or female. Few folded male and immature female were found. Only the double sexual larva infected mice or rabbits had schistosome eggs in the liver and the liver had typical schistosome egg nodules. The sin?gle sexual larva infected mice or rabbits had no schistosome eggs or schistosome egg nodules in the liver tissues. The single male larva could develop to worms with the testis,and with a little smaller size compared to the mature folded male,while the single sexual infection female worm could not develop to the mature stage with much thinner and smaller compared to the mature folded female. Conclusions The male or female worms from single sexual infection are smaller than those from double sexual infection (mature worms?folded male and female). So it is necessary to check single sex worms in vessels of intestinal mucosa thoroughly in the sentinel mice when no schistosome eggs were found in the liver.