NATURAL TRANSMISSION OF PNEUMOCYSTIS-CARINII IN NONIMMUNOSUPPRESSED ANIMALS - EARLY CONTAGIOUSNESS OF EXPERIMENTALLY INFECTED-RABBITS (ORYCTOLAGUS-CUNICULUS)

Airborne transmission of Pneumocystis carinii has been established, bu t the infective form and the sources of infection remain unknown, Anim al models for studies of P. carinii have previously been limited to im munosuppressed rodents; however, this study was performed with nonimmu nodepressed P. carinii-free rabbits. This study was aimed at determini ng (i) the delay between inoculation of animals (day zero [D0]) and th e onset of contagiousness and (ii) the end of contagiousness of these animals (donors). Five-week-old rabbits were used as contact animals a nd were housed with the donors. The cohabitation periods were for 4 or 5 days from D0 to D4, D4 to D8, D8 to D13, D13 to D18, and D18 to D22 . The highest parasite burdens were observed in contact animals housed with donors from D8 to D13 or D13 to D18, This period (8th to 18th da y following the day of inoculation of donors) might correspond to the highest phase of contagiousness of donors.