GoogleTrends reflects the abundance of the Asian tiger mosquito (Aedes albopictus): a call for the web-based surveillance of invasive alien vector species

Abstract

The Asian tiger mosquito (Aedes albopictus) is becoming widespread in Europe, where it can transmit some major arboviruses, including Chikungunya and Dengue. While surveillance initiatives are being implemented and harmonized between states, the spread of A.albopictus is outrunning them and cost-effective surveillance tools are needed.In this study, we tested whether on-line searches on Google can be adopted to monitor the abundance of A.albopictus. By using data from a long-term monitoring program in the Emilia-Romagna region (Italy), we tested whether the monthly level of infestation was causally related to the monthly GoogleTrends index for the species.The logarithm of the level of infestation from A.albopictus had a very strong causal effect over the total volume of Google searches about the species. Our statistical model was highly predictive for the GoogleTrends index, suggesting that this cheap on-line metric can be adopted as a proxy for the real level of infestation from A.albopictus.While GoogleTrends has been adopted to identify and monitor epidemics, including vector-borne diseases, no study tested whether it can reflect the numerical abundance of vector species. To the best of our knowledge, our study, among the few validating GoogleTrends with surveillance data, was the first one opening this possibility. Therefore, we believe that the analysis of on-line search volumes might become an important complement to existing surveillance initiatives for invasive vector species worldwide.

Combining surveys and on-line searching volumes to analyze public awareness about invasive alien species: a case study with the invasive Asian yellow-legged hornet (Vespa velutina) in Italy

“…As GoogleTrends can be downloaded at the regional level, peaks in searches about V. velutina could signal the colonization of a certain area by the species. This approach is already adopted in epidemiology, to trace the circulation of viral disease [35] , and other studies considered it for the monitoring of common invasive alien species, such as the tiger mosquito (Aedes albopictus) [36] . As V. velutina actively exploits human buildings for constructing its nests, becoming visible and concerning to residents, this approach should work well in its invaded range, due to the high proportion of urban and rural landscapes.…”