Evidence for regurgitation by Amblyomma americanum.

Western blot analysis of Amblyomma americanum-derived midgut extracts using tick-resistant rabbit and guinea pig antisera demonstrated several unique polypeptides ranging from 7 to 355 kDa. These polypeptides were not observed in similar blots of salivary gland extracts or serum from the respective host animals. The data from this study suggest that female A. americanum ticks regurgitate gut material during feeding. Such a finding explains the ability of immunization with gut-derived preparations to induce immunity and may help to understand the mechanism of transmission of several tick-borne pathogens that have been only clearly demonstrated to infect the gut of ticks.