Local authorities, tourist enterprises and those in the agricultural and industrial sectors, among others, must adopt measures to prevent and control the mosquito that transmits Zika and dengue fever, 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 reinforce 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 detection of cases of disease, as defined in the National Plan for the Prevention and Control of Vector-Borne Diseases.
“Based on entomological analyses carried out by the REVIVE network, the presence of pathogenic agents in mosquitoes has not been verified to date, nor have any autochthonous cases of diseases for which the vector is capable been reported,” he highlights.
Vector prevention and control activities involve the involvement of different sectors, namely local authorities, tourism, hotels, the environment, veterinary services, agriculture, industry, commerce, among others, complementing the efforts of the health sector in the prevention and control of diseases transmitted by the Aedes albopictus and Aedes aegypti mosquitoes, such as dengue fever, chikungunya, zika, yellow fever, all of which are mandatory to be notified, and infection by the heartworm 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) phases.
Physical environmental intervention is the primary method of vector control, requiring multisectoral interventions to identify and eliminate breeding sites (places and containers that may 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 mosquitoes of the Aedes genus (Level 1), the location and mapping, preferably with georeferencing, of places where the existence of breeding sites may constitute a risk for the multiplication of mosquitoes must be ensured.
It is the responsibility of local authorities to map public and private structures that may be suitable locations for the existence of breeding sites, spread throughout their area of intervention.
People involved in vector prevention and control actions must wear clothing that covers the entire body and use repellents.
Whenever there is a change in the Risk Level, the Public Health services network is responsible for communicating this change and promoting 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 could constitute an emergency in Portugal and at a cross-border level”, says the DGS, highlighting that “the increase in international mobility of people, goods and animals, combined with climate change, are factors that contribute to the expansion of invasive mosquitoes and the consequent occurrence of cases of disease”.
The presence of invasive Aedes mosquitoes in Portugal began with the detection of Aedes aegypti in Madeira in 2005. The species Aedes albopictus was introduced to the mainland in 2017 in the North (Penafiel), in 2018 in the Algarve (Loulé) and in 2022 in the Alentejo (Mértola).