Congenital infections in the neonate have been described for a variety of opportunistic pathogens affecting the mother. These include Mycobacterium tuberculosis, cryptococcal infection, CMV, PCP and toxoplasmosis. Vertical transmission is generally assumed to be the route of infection, although in some cases it may not be clear whether the neonate acquired the infection in utero or during the perinatal or postnatal period. It is essential that neonates born to HIV-seropositive women should be assessed by a paediatrician, and where necessary actively screened, for congenital opportunistic infections. The placenta should also be examined histologically for signs of infection or disease.