ARMADILLOS

0 NE of the primary restrictions in leprosy research has been the limited amount of Mycobacterium leprae available. M. leprae has not yet been acceptably grown in vitro and, until the discovery of the susceptibility of the nine-banded armadillo (Dasypus novemcinctus) to experimental infection with M. leprae (Kirchheimer and Storrs, 1971), it was not possible to obtain large numbers of leprosy bacilli for experimental purposes. Now with the relatively large amounts of M. leprae available, new informa-tion on the antigenic structure and other characteristics of armadillo-grown M. Zeprae has been obtained. However, for optimal use of the armadillo as a source of M. Zeprae more information is needed about several features of the infection in this animal. As only 40-60 % of armadillos develop disseminated disease, even after intravenous inoculation with 1-10 x lo7 M. Zeprae (Storrs et al., 1974; Rees, 1976; Kirchheimer and Sanchez, 1977), it would be an advantage for the economical production of large amounts of infected tissues, if it were possible to identify at an early stage those animals developing a pro