As every year, with the rise in temperatures, the season of the tiger mosquito begins in Spain, a public health problem with which it is also necessary to deal in a scenario marked by the COVID-19 pandemic.
The tiger mosquito ( Aedes albopictus ) is an invasive exotic species native to Southeast Asia that was first detected in Spain in 2004. Since then, its presence has been registered in new municipalities and provinces every summer. The main impact of the entry of this mosquito into the peninsula is of a sanitary nature: it is a vector of transmission of various diseases such as chikungunya, dengue or Zika. We are talking about conditions that are not endemic in our country but that could become so: in 2018, for example, there were already six local cases of people infected with dengue within Spain.
Is it possible to get COVID-19 through a mosquito bite?
At a time when we are especially sensitive to everything related to the spread of diseases, many people wonder if mosquitoes are vectors of SARS-CoV-2 transmission. At this point, experts agree that while Aedes mosquitoes are capable of transmitting 22 different types of viruses, they do not have the potential to spread COVID-19 .
The World Health Organization has recalled that there is currently no indication that it is possible to become infected through the bite of a mosquito, and that the main vehicle for the spread of SARS-CoV-2 are the droplets that an infected person expels when coughing or sneezing . “At this time there is no evidence to suggest that pests such as mosquitoes and ticks may be involved in the transmission of COVID-19,” explains Jim Fredericks, entomologist with the National Pest Management Association (USA) in a statement from said entity. “However, you have to remember that they can transmit other serious diseases such as West Nile virus and Lyme disease.”
What will the 2020 tiger mosquito season be like?
It is believed that the reduction in tourism as a result of the new coronavirus crisis will also decrease the transmission associated with the bite of the tiger mosquito. “Although the discomfort caused by mosquitoes will not decrease, in 2020 we can expect less probability of autochthonous cases of these diseases such as those detected in recent years in Andalusia, Murcia and Catalonia “, explains Frederic Bartumeus, ICREA researcher at CEAB-CSIC and CREAF, and director of the Mosquito Alert project.
Experts also warn of the possible arrival of the yellow fever mosquito ( Aedes aegypti ), originally from Africa and which was detected in the Canary Islands in 2017, although it could be eliminated thanks to local management. On the other hand, it is expected that this summer a part of the Spanish territory will coexist with another newcomer, the Aedes japonicus , a mosquito of Asian origin.
Mosquito Alert: Citizen Science to Spy on Invaders
Mosquito Alert is a citizen science project coordinated by different public research centers and created to investigate and control disease-transmitting mosquitoes. Through a mobile application, anyone can report a possible finding of a tiger mosquito or yellow fever mosquito and their breeding places on public roads by sending a photo. These data are very valuable, as they complement scientific work and allow public health managers to use this information to monitor and control the spread of these mosquitoes in neighborhoods and cities.
Participating is very simple: just download the free app available on the project website. “At the moment, the application allows to give warnings about the tiger mosquito and the yellow fever mosquito,” explains Alex Richter Boix, biologist, communication technician at CREAF and member of the Mosquito Alert team. “Users who wish to participate only have to upload a photo of the mosquito, if the thorax can be seen, which is what allows the species to be identified, and then mark where they have found it. The app has a GPS so the location can be used automatically, or it can be marked manually on a map ”.
Although all photos are reviewed by entomologists, tiger mosquitoes are easy to identify. “The tiger mosquito is a black mosquito with white stripes. It is easily identified by the white band on the head and thorax ”, the expert explains. “The yellow fever mosquito, on the other hand, is dark brown, with white stripes as well, but on the thorax it has four lines that draw a lyre.”
More than 70 million people exposed
Only with the data collected thanks to the Mosquito Alert application, in 2019 it was possible to confirm the presence of the tiger mosquito in 251 Spanish municipalities where more than thirteen million people live together.
If we add to this figure the tourists in these populations, the number of the population that was exposed to the mosquito in 2019 increases by 59 million. Therefore, we are talking about more than 70 million people who were at risk of exposure to the tiger mosquito in 2019.
Attention to climate change
Global warming is causing many species in warm latitudes to expand their ranges. “All studies predict that the habitable territory for both the tiger mosquito and the yellow fever mosquito will increase in the coming years,” explains Richter Boix. “The increase in temperature will allow, especially the yellow fever species, to complete its cycle in areas outside the tropics and subtropics. Many of these models suggest that in twenty or thirty years the south of the peninsula and other Mediterranean regions will have favorable conditions for the yellow fever mosquito to settle. The tiger mosquito, in turn, will continue to expand towards northern Europe ”.
