Study on placental transmission of Pneumocystis carinii in mice using immunodeficient SCID mice as a new animal model.

Placental transmission of Pneumocystis carinii in mice was examined in 39 animals obtained by caesarean section from 17 pregnant SCID females experimentally infected with P. carinii. When examined with toluidine blue O, DAPI and immunofluorescent antibody stains, P. carinii was detected in the lungs of infected mothers but not in the lungs of caesarean section-derived neonates even after the neonates were treated with dexamethasone for 8 weeks. However, 13 neonates born to five infected females developed P. carinii pneumonia. These results indicate that P. carinii cannot be transmitted transplacentally in mice.