Invasion of skin by larvae of the cat hookworm,Ancylostoma tubaeforme

A modification of the ‘floating raft’ method ofin vitropenetration study is described. This allows replication of results and additional conveniences in operation. Filter paper membranes have shown characteristics similar to those of skin and have been used for quantitative studies. A method of digesting penetrating larvae from skin has been used to reduce the variability inherent in whole skin. Neither chloroform soluble skin products nor gravity were found to have a significant effect on the number of larvae entering membranes. Exsheathment of larvae was not essential prior to penetration and no specific stimuli for exsheathment appear to be necessary. Scanning electron micrographs have shown that entry may be by either hair follicles or desquamations of the stratum corneum. No evidence of enzymic activity during the invasion process has been found so far and the results suggest that a mechanical rather than chemical system obtains.