Role Of Vertical Transmission In Mosquito-Borne Arbovirus Maintenance And Evolution

Vertical transmission (VT) of arboviruses provides a unique mechanism for arbovirus maintenance during adverse environmental conditions and amplification in nature. The mechanisms by which most arboviruses are trans-seasonally maintained remain unclear:There is evidence for VT by either transovarial or transovum transmission of the virus from mother to progeny in each of the major arbovirus families. However, the VT rates observed in field and laboratory studies seem insufficient to maintain the viruses in nature. Stabilized infection may condition maintenance of arboviruses and insect-specific viruses in the arbovirus families in nature. Stabilized infection of Drosophila maintains Sigma virus (family Rhabdoviridae) in nature in the absence of horizontal amplification of the virus in a vertebrate host. La Crosse virus maybe maintained in Aedes triseriatus by stabilized infection. Stabilized infection could be a unifying mechanism for trans-seasonal maintenance of arboviruses and related viruses from different families. VT and long term persistent infections promote arbovirus evolution in vectors. Understanding the role of VT in maintenance, evolution, and emergence of arboviruses is critical to prevent and control these threats to public and animal health.