Temperate Conditions Limit Zika Virus Genome Replication.

Area of Science:

• Virology
• Vector-borne diseases
• Epidemiology

Background:

• Zika virus (ZIKV) causes severe birth defects and neuroimmunological disorders.
• Temperature significantly influences vector-borne disease transmission by affecting mosquito vectors and viruses.
• Previous studies showed ZIKV transmission decreases at cooler temperatures.

Purpose of the Study:

• To investigate the mechanisms behind temperature-induced changes in ZIKV transmission.
• To determine how temperature affects ZIKV replication steps in mosquito cells.
• To differentiate temperature effects on Asian and African ZIKV lineages.

Main Methods:

• ZIKV replication steps were analyzed in C6/36 mosquito cells at optimal (28°C) and cool (20°C) temperatures.
• Virus entry, translation, and genome replication were assessed.
• The impact of temperature shifts on replication complex formation was evaluated.

Main Results:

• Cool temperatures (20°C) did not affect ZIKV entry or translation.
• Genome replication was impaired at 20°C, evidenced by reduced double-stranded RNA intermediates.
• If replication complexes formed at 28°C, late replication steps were completed efficiently upon shifting to 20°C.
• The Asian ZIKV lineage showed restricted replication at 20°C, while the African lineage was less affected.

Conclusions:

• Cool temperatures decrease ZIKV genome replication efficiency in mosquito cells.
• Temperature-dependent replication is a key factor in ZIKV transmission dynamics.
• Understanding these mechanisms aids in predicting arboviral disease seasonality and developing control strategies.