Assessing Urban Yellow Fever Transmission Risk: Aedes aegypti Vector Competence in Argentina

Area of Science:

• Medical Entomology
• Virology
• Public Health

Background:

• Yellow fever (YFV) poses a historical threat, with past epidemics linked to Aedes aegypti mosquitoes in Argentina.
• While sylvatic vectors caused epizootics after Aedes aegypti eradication, its recolonization increases urban YFV transmission risk.
• The reasons for the absence of urban YFV cycles in South America remain unclear.

Purpose of the Study:

• To investigate the vector competence of Argentine Aedes aegypti populations for Yellow Fever Virus transmission.
• To assess the potential for urban Yellow Fever Virus transmission given current mosquito populations and viral strains.

Main Methods:

• Evaluated vector competence of Aedes aegypti colonies from central and northwestern Argentina for YFV.
• Utilized a 2009 YFV strain isolated from Sabethes albiprivus.
• Assessed mosquito infection, dissemination, and transmission rates by examining viral presence in mosquito bodies, legs, and saliva at various time points.

Main Results:

• Both Argentine Aedes aegypti colonies demonstrated competence as YFV vectors, though with inter-colony variations.
• Early YFV infection was observed in the La Plata colony as early as 3 days post-infection (DPI).
• Results indicate a significant capacity for YFV transmission by these mosquito populations.

Conclusions:

• Argentine Aedes aegypti mosquitoes are competent vectors for Yellow Fever Virus.
• Early infection rates suggest a heightened risk for urban YFV transmission.
• Enhanced surveillance and targeted vector control in urban areas are essential to prevent future outbreaks.