Evolutionary influences in arboviral disease.

Area of Science:

• Virology
• Evolutionary Biology
• Genetics

Background:

• Arthropod-borne viruses (arboviruses) necessitate replication in both arthropod vectors and vertebrate hosts.
• This dual-host requirement imposes significant evolutionary constraints, limiting arbovirus diversity to specific viral families.
• Phylogenetic and molecular studies suggest a balance of purifying and positive selection shaping arbovirus evolution.

Purpose of the Study:

• To investigate the evolutionary pressures on arboviruses resulting from alternating replication in arthropod and vertebrate hosts.
• To reconcile conflicting findings from in vitro studies on host specialization and fitness.
• To highlight the need for in vivo models and reverse genetics to understand arbovirus adaptation and disease emergence.

Main Methods:

• Analysis of phylogenetic data to infer evolutionary selection pressures.
• Molecular genetic studies examining mutations affecting replication in different host cells.
• Review of experimental model systems using arthropod and vertebrate cell cultures.

Main Results:

• Phylogenetic studies indicate purifying selection dominates arbovirus evolution, with some evidence of positive selection.
• Molecular studies show mutations impacting differential replication in arthropod and vertebrate cells.
• In vitro experimental systems provide inconsistent results regarding host specialization and fitness trade-offs.

Conclusions:

• Arboviruses must balance fitness across disparate arthropod and vertebrate hosts.
• Conflicting in vitro data necessitate further investigation.
• In vivo studies and reverse genetics are essential for predicting arbovirus adaptation and emergence.