Schematic outcomes of an intrauterine infection with Coxiella burnetii in a pregnant animal. Little knowledge on the intrauterine spread of C. burnetii is present, but data indicates that the infection may follow one of two routes after an initial localization in the placenta (indicated by red and greens arrows). A latent infection (green arrows) that either remains localized in the placenta or spreads to the fetus (still latent) is probably the most common outcome, at least in cattle. This situation is characterised by normal offspring that may or may not be congenitally infected and vaginal excretion of organisms in association with parturition and in the postpartum period. An active infection (red arrows) that may remain limited to the placenta, although being widespread, or may spread to the fetus by the haematogenous or the amniotic-oral route will most likely compromise the fetus and cause abortion, premature delivery, stillbirth and weak offspring (APSW Complex) although normal but probably congenitally infected offspring may also be found.