[Studies on chemotactic behaviors of Strongyloides ratti infective larvae in vitro and migration routes of the larvae in rat head].

For the purpose of clarifying host-finding mechanisms, the infective larvae of Strongyloides ratti were run on an agarose plate which had been placed various attractants around the larvae. They were accumulated at the sites of sodium compounds, serum proteins and albumins. At 20, 30, 40 hours after infection, rats were killed and heads were separated. They were then processed for thin section specimens. Larvae were found in brains, olfactory bulbs and its nerves. These larvae seemed to move along olfactory nerves during descending from the cranial cavity. Another migration study was done by whole body autoradiography after 35S-methionine labeling for clarifying the larval pathway how to invade cranial cavity in the rats. They first crawled under subcutaneous region of rat and then accumulated at the tip of the nose. Next, they began to ascend olfactory nerves. They were in cranial cavity up to 20 hours after infection and then descending same route to nasal cavity. I don't know why they aim the cranial cavity but they had necessity to invade the cranial cavity and stay there for appropriate time to be an adult in the intestine.