Placental or fetal tissues from 18 (22%) of the 81 pregnancy losses tested positive for Zika virus by RT-PCR, including 4/13 (31%) with recent unspecified maternal flavivirus infection, 2/18 (11%) with negative maternal Zika virus IgM, where possible maternal exposure occurred >12 weeks before serum collection, and 1/16 (6%) with no maternal clinical samples tested (Table 2). The gene discussed is CD40LG; the disease is Flavivirus Infections.