The Asian tiger mosquito, ‘Aedes albopictus’, originating from Southeast Asia and known for transmitting viruses and parasites causing diseases such as chikungunya, dengue, yellow fever, Zika, and Japanese encephalitis, is the focus of the 2024 report by the Vector Surveillance Network (Revive). The report, released by Portugal’s National Health Institute Ricardo Jorge (Insa), highlights the spread of this mosquito species.
Since 2017, ‘Aedes albopictus’ has been identified in Portugal’s North, Algarve, Alentejo, Lisbon, and, for the first time in 2024, in the Central region, indicating an “establishment and geographical dispersion” across multiple areas of the country.
“These species are vectors for viruses like dengue, Zika, and chikungunya and have been expanding their geographical distribution in these regions. In 2024, ‘Aedes albopictus’ was identified in 20 municipalities across the country,” the report states.
This situation represents a “heightened public health risk,” necessitating constant monitoring and the implementation of “effective control measures aimed at reducing/eradicating the detected populations” to prevent further spread.
‘Aedes albopictus’ has been globally dispersing, primarily through the passive transport of eggs via commercial activities.
In Europe, chikungunya and dengue outbreaks associated with this species have been recorded since 2010. Initially detected in Albania in 1979, the species is now spread across many countries.
Regarding another species, ‘Aedes aegypti’, once present in mainland Portugal until the 1950s, the report notes its detection in Madeira in 2005. Despite combat measures through disinfections, it has established itself on the island and is currently a public health concern in the municipalities of Funchal and Câmara de Lobos.
The report emphasizes ‘Aedes aegypti’ as a species of great medical importance, being the primary vector of dengue, yellow fever, Zika, and chikungunya, while also capable of transmitting the West Nile virus, myxomatosis, avian plasmodium, and filaria.
The 2024 Revive fieldwork, marking the program’s 17th year, occurred from May to October during peak mosquito activity in various mainland Portugal municipalities, and from January to December in Madeira, focusing on entry points like airports and ports and zones where invasive species were identified.
A total of 38,522 mosquitoes from 18 species and 65,802 eggs from invasive species were identified. The samples tested for the presence of human-pathogenic flaviviruses and alphaviruses returned negative results.
Revive is a protocol involving the Directorate-General of Health, former regional health administrations of the Algarve, Alentejo, Center, Lisbon and Tagus Valley, and North regions, along with the regional health directorates of Madeira and the Azores and the Insa.
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