Vertical Transmission of Bovine H5N1 in Pregnant and Lactating Mice
A recent bioRxiv preprint examines the pathogenesis and transmission dynamics of the bovine-derived H5N1 influenza A virus (genotype B3.13) during pregnancy in a murine model. Pregnant mice were infected at defined gestational stages to characterize maternal–fetal viral dissemination, evaluate the likelihood of vertical transmission, and determine postnatal developmental consequences. The study shows that bovine B3.13 H5N1 is capable of in utero transmission, with viral antigen detected in placental and fetal tissues, particularly following mid-gestation infection (E10). Exposure during this stage produces placental infection, fetal viral presence, and detrimental outcomes including intrauterine growth restriction. Infection at late gestation (E16) leads to viral transmission through milk and induces persistent systemic inflammation in neonates. The findings indicate that H5N1 can cross maternal-offspring barriers in mammals, representing a potential developmental hazard and underscoring concerns about zoonotic risk as this virus continues to expand across diverse mammalian hosts.
