Rapid molecular method for early detection of the invasive mosquito Aedes aegypti (Linnaeus, 1762) at Points of Entry.

Abstract

In recent years, globalization and climate change have led to a rise in the number of imported cases of Aedes-diseases in Europe, resulting in increased frequency and magnitude of local transmissions due to the presence of competent vectors. Recently, Italy has experienced the establishment of three exotic Aedes mosquitoes relevant to human health, Aedes albopictus, Aedes koreicus and Aedes japonicus. Aedes aegypti, the primary vector of dengue and yellow fever, distributed in tropical and subtropical regions, has recently reappeared in Europe and the risk for its re-introduction in Italy is high given the climatic conditions suitable for the species. To address the risk of introduction and spread of Aedes-diseases, the Health Authorities recommend the strengthening of entomological surveillance at regional level, particularly in strategic areas and Points of Entry, such as ports and airports. In 2021, a Korean research team developed a multiplex-PCR assay for the identification of six Aedini species, not including Ae. aegypti. In the present study, the previous diagnostic test was improved by designing reverse primers for the identification of Ae. aegypti and Aedes geniculatus. This latter native mosquito lays eggs morphologically similar to those of invasive species with which it can sometimes be found in sympatry. Furthermore, a ten-minute DNA extraction method was implemented. The results obtained demonstrate a perfect diagnostic capacity and sensitivity of the method in discriminating the five species tested. Here, findings of a sensitive, rapid and cost-effective molecular assay developed for the early identification of invasive species at high-risk sites are shown.