Local authorities, tourist resorts and entities in the agricultural and industrial sectors, among others, should adopt measures to prevent and control the mosquito that transmits Zika and dengue, which has already been detected in Portugal, recommends the DGS.
In a guideline published on its website, the Directorate-General for Health (DGS) states that, given the detection of the invasive species Aedes albopictus in different parishes and municipalities in mainland Portugal, it is important to strengthen prevention and control mechanisms aimed at reducing the abundance or eliminating this species of mosquito.
According to the DGS, the most recent detections of the invasive mosquito in Portugal correspond to risk level 1 (yellow), on a scale of 0 to 3, defined according to the different scenarios regarding the presence of Aedes mosquitoes and the detection of cases of disease, as defined in the National Plan for the Prevention and Control of Vector-Borne Diseases.
“Based on the entomological analyses of the REVIVE network, no pathogens have been found in mosquitoes to date, nor have any autochthonous cases of diseases for which the vector is competent been reported,” he points out.
Vector prevention and control activities involve different sectors, including local authorities, tourism, hotels, the environment, veterinary medicine, agriculture, industry and commerce, among others, complementing the health sector’s efforts to prevent and control diseases transmitted by the Aedes albopictus and Aedes aegypti mosquitoes, such as dengue fever, chikungunya, Zika, yellow fever, all of which are notifiable, and infection by the dirofilaria parasite.
Vector control of Aedes albopictus involves interventions in the mosquito’s life cycle, which includes the aquatic (eggs, larvae and pupae) and terrestrial (adult mosquito stages) phases.
Physical environmental intervention is the primary method of vector control, requiring multisectoral interventions to identify and eliminate breeding sites (places and containers that can serve as habitats for mosquito eggs and larvae) and the application of larvicides and adulticides may also be necessary, depending on the level of risk assessed by public health services.
In areas with confirmed detection of Aedes mosquitoes (Level 1), the location and mapping, preferably with georeferencing, of places where breeding sites may constitute a risk for mosquito multiplication should be ensured.
It is the responsibility of local authorities to map public and private structures that could be breeding sites, scattered throughout their area of intervention.
People involved in vector prevention and control should wear clothing that covers their entire body and use repellent.
Whenever there is a change in the Risk Level, the network of Public Health services is responsible for communicating this change and promoting the appropriate measures with partner entities, based on this Guideline and other documents that may be issued by the DGS.
“Mosquito-borne diseases are an emerging global public health problem that may constitute an emergency in Portugal and across borders,” says the DGS, stressing that “the increased international mobility of people, goods and animals, combined with climate change, are factors that contribute to the expansion of invading mosquitoes and the consequent occurrence of disease cases.”
The presence of invasive Aedes mosquitoes in Portugal began with the detection of Aedes aegypti in Madeira in 2005. The Aedes albopictus species was introduced to the continent in 2017 in the North (Penafiel), in 2018 in the Algarve (Loulé) and in 2022 in the Alentejo (Mértola).
