Eastern equine encephalitis virus in birds: relative competence of European starlings (Sturnus vulgaris).

The study examines if the eastern equine encephalitis (EEE) virus impacts starlings more intensely than other native birds, and its findings suggest that starlings, in comparison to other birds, experience more intense and longer lasting viremias. The research also suggests that starlings can potentially infect more mosquitoes with the EEE virus than other native birds.

Objective of the Study

• The study aimed to understand if the effects of the eastern equine encephalitis (EEE) virus are more severe in starlings (a non-native bird species) compared to other native birds. This understanding works towards defining any possible differences among various bird species in their roles as reservoirs for transmitting this virus.

Methodology and Findings

• The study compared the intensities and durations of viremia or presence of viruses in the bloodstream in starlings and various native birds. It was found that viremias in starlings were more intense and lasted longer than in other birds such as robins.
• Different types of mosquitoes such as Aedes and Culiseta melanura were tested under lab conditions to see whether they could acquire EEE viral infection from infected starlings. The tests confirmed this possibility.
• It was noted that starlings often died when their viremia started to decline, whereas most other birds generally survived.

Conclusion

• Reservoir competence of a bird species is defined as the product of its infectiousness (the proportion of feeding mosquitoes that become infected) and the length of infectious viremia.
• Although starlings are not native to areas where EEE is commonly found, it was noticed that a starling could infect about three times as many mosquitoes as a robin could, indicating their efficiency as a disease vector.
• The study therefore concludes that starlings, despite being non-native, may play a significant role in the transmission cycle of the EEE virus.