The Ministry of Health has once again implemented the procedure outlined in the Entomological Surveillance System of the islands after discovering specimens of the Aedes albopictus species in various stages of development at the Santa Cruz de Tenerife port.
More specifically, the specimens were located inside two containers from the Castellon area where they were residing.
Upon analysing the samples on July 4, the presence of mosquito Aedes albopictus larvae and pupae was confirmed in multiple olive trees that were transported within containers to the Santa Cruz de Tenerife port, one of the active sites of the surveillance system since the discovery of a specimen of Aedes aegypti in January 2023.
Following this recent detection, fumigation measures have been carried out on both the containers and their contents as a precautionary step.
Furthermore, the General Directorate of Public Health has notified the Port Authorities of Santa Cruz de Tenerife and Las Palmas, as well as the City Council of Santa Cruz de Tenerife, about these findings to initiate the actions outlined in the protocol.
Preventive Actions
The Public Health and Surveillance System team is already devising an initial preventive strategy by increasing the number of traps placed at different key locations compared to the standard protocol. The traps are being deployed at high-risk spots, particularly where the specimens were discovered and nearby areas.
Consequently, the surveillance system has intensified its sampling in the region, inspecting potential breeding grounds that could lead to the vector’s dispersion. In the recent months following various sightings of Aedes aegypti in the port region, entomological surveillance efforts have been ongoing and are currently reinforced through an augmented number of traps and increased sampling frequency.
In this context, the Canary Islands are stressing to the national authorities the necessity of amping up control measures on vessels arriving from areas where Aedes mosquitoes are firmly established, given that one confirmed entry route of these invasive mosquitoes into the archipelago is through the trade of plants from regions at risk where this type of mosquito resides.
Additional Sightings
Since January 2023, Aedes aegypti have been periodically detected at the Port of Tenerife in February, March, and May 2023, and a specimen of Aedes albopictus was also found last November, which was associated with ship traffic as well.
Furthermore, presence of Aedes aegypti was identified in the Port of Las Palmas, Gran Canaria, during November 2023 and January 2024. Nevertheless, no breeding grounds were discovered in any of these instances, nor were there reports of bites from port workers.
Public Involvement
Citizen participation is particularly crucial at this juncture to prevent the proliferation of breeding sites and to spot potential specimens. Individuals can send pictures of suspected Aedes presence or images of severe inflammatory reactions due to bites to the email [email protected], specifying the exact geographical location and providing a contact number.
The Aedes mosquitoes are smaller than ordinary mosquitoes, dark in colour, with silver stripes on their bodies and legs with white bands. They typically bite at dawn or dusk without emitting the common mosquito’s buzzing sound. Only the female mosquitoes bite as they require a blood meal for reproduction and water (breeding sites) to complete their life cycle. They lay their eggs in water, from which larvae emerge and subsequently develop into pupae (both in aquatic environments), eventually maturing into mosquitoes. Any spot where water collects can serve as a breeding site, making it imperative to eliminate such areas.
Preventative Measures
The first step is to control and eradicate all water accumulations since even the smallest amount, like a bottle cap, can serve as a breeding site. To achieve this, it is advisable to:
- Place sand in pot saucers to allow for watering without leaving saucers with water for females to deposit eggs. Alternatively, empty and clean saucers once a week to impede the development of eggs deposited by females into adult mosquitoes.
- Avoid growing plants directly in water (e.g. pothos, bamboo, money plant) by planting them in soil. Change the water in vases daily.
- In outdoor areas (gardens, patios, rooftops, balconies), flip over empty flower pots, bottles, buckets, and any other containers where water from irrigation or rainfall can collect.
- Eradicate puddles in gardens, rooftops, balconies, or terraces after watering or rain. Keep these areas tidy and remove any debris where water may accumulate.
- Regularly clean and change the water in pet bowls. Ensure that water tanks are securely covered to prevent mosquito entry, as well as other containers used to collect rainwater.
- Maintain swimming pools well chlorinated and circulated daily. If pools are empty or contain little water, they pose a significant risk for mosquito breeding.
- Clean the vents on refrigerators and air conditioning units outdoors where water can collect, including reservoirs of portable equipment.
- Keep drainage systems in outdoor areas clean, ensuring water does not stagnate in any part.
