Why are there more mosquitoes and more pests that affect biodiversity and transmit diseases? It is obvious that It is increasingly common to find information about the occurrence of deaths associated with mosquitoes.the arrival of pests and the environmental impact they generate.
In Spain we are facing a situation that worries citizens, scientists and administrations affected by a bite with many effects. More and more presence of invasive mosquito species capable of transmitting traditionally tropical and subtropical viral diseases.
And of course, among the causes of this increase, there is inevitably the climate change and rising temperatureswhich favors a greater proliferation of these insects, a phenomenon in which globalization also plays an important role.
Tropicalization and human activity
An explosive cocktail, tropicalization And human activitywhich opens the door to the arrival in our country of new species of mosquitoes capable of causing more damage to living beings and biodiversity.
We are already getting used to hearing the alerts on the West Nile virus, dengue or malariadiseases linked to mosquitoes which transmit the pathogens causing these diseases and which are increasingly found in our territory.
West Nile Virus
West Nile virus is a mosquito-borne viral disease first identified in Uganda in 1937 and now widespread in Africa, Europe, the Middle East, North America, and Western Asia. The virus is transmitted mainly by the common mosquito (Culex pipens) and for years it has been detected in mosquitoes as well as in humans, as well as in horses and various species of birds.
dengue virus
He dengue virus It can be transmitted by the tiger mosquito (Aedes albopictus), an invasive species originating from Southeast Asia and first detected in Spain in 2004 in Catalonia.
Since then, this species has managed to colonize, among other things, urban environments throughout the Mediterranean arc: from CFrom Ataluña to Andalusia, including also the Balearic Islandsas well as the northern peninsula in communities such as Aragon, Navarre, the Basque Country or Galicia, and increasingly inland areas, such as the Community of Madrid.
The forecasts are not good and entomologists no longer confirm not only Tiger mosquito expansion trendbut its definitive future settlement over the next five years in each of the Autonomous Communities of Spain.
Malaria
THE malaria or malaria is a serious disease present in many tropical countries, caused by infection with protozoa of the genus Plasmodium transmitted by mosquitoes of the genus Anopheles.
A CSIC study revealed in May this year that the mosquito Anopheles maculipennis It is widely distributed in Spainwith a particular predilection for river mouths and valleys with irrigated agricultural areas. Although the disease was eradicated in Spain sixty years ago, Every year, nearly 800 new imported cases are detected.
So we see that the importation of mosquitoes or associated diseases are on the agenda and their presence is constantly on the radar of researchers in the field of health and the environment.
Deadly mosquitoes
For Martina Ferraguti, a researcher in conservation biology and global change at the Doñana Biological Station (EBD-CSIC), “these tiny insects, in addition to being a great nuisance for many of us, These are the deadliest animals on our planet because of the multitude of pathogens they are capable of transmitting”
The researcher, focused on studying the impact of biodiversity on diseases transmitted by these insectsexplains in an article published by Greenpeace that “mosquitoes, with their many species, play a crucial role as vectorsthat is, as carriers of diseases that affect both humans and wildlife.
In his research, Ferragutti tries to understand the ecological and evolutionary factors which affect the transmission of vector-borne diseases.
He points out that “although there are thousands of species (about 3,700 species and more than 40 genera), it is interesting to note that only a small percentage of them, less than 10%, are responsible for the transmission of pathogens harmful to human health. “This fact highlights the need to focus our research on particular species of vector mosquitoes.”
Temperatures
According to a new report from the World Meteorological Organization (WMO), there is an 80% chance that the planet’s average annual temperature will temporarily exceed 1.5°C pre-industrial levels in at least one of the next five years.
Low winter temperatures in many temperate regions also prevent survival of the larvae of these insectswhich prevents infections in these places by avoiding the presence of the vector during certain months of the year.
Warmer weather
“A warmer climate with milder winters like those we experience year after year in Spain favors the appearance of diseases considered as typically tropical in our latitudes” recalls Ferragutti.
For the scientist, climate change “has altered weather patterns on a global scale, generating conditions more conducive to growth.” proliferation of various species of mosquitoes“.
The consequences of the Higher temperatures and changing precipitation patterns I had some environments increasingly suited to the maturation of their larvae and the development of the adult phasewhich leads to an increase in its population and a geographical expansion.
As temperatures rise, mosquitoes shorten their activity cycle, They reproduce more times per year and extend their daily activity periodwhich increases the risk of disease transmission. A striking example is the tiger mosquito, native to tropical regions of Asia.
Not just climate change
The CSIC researcher emphasizes that “it is important to note that in this changing world, climate change does not act alone. The interdependent processes that are part of global change give birth to a new interface vector-animal-reservoir-pathogen“.
In this scenario, the Human populations and animals are exposed to “previously unknown pathogens”leading to the emergence of new diseases and the spread of others already known to regions of the world where they were not previously transmitted.
“These processes are linked or facilitated by certain human activitiesraising the question of how to achieve economic and social development without compromising the health of all,” Ferraguti concludes.
How to fight them
Episodes such as the appearance of the tiger mosquito in Extremadura or the West Nile virus in Andalusia, since Environmentalists in action either SEO/BirdLife They demand that solutions come through natural treatments or other more drastic measures, always avoiding chemical pesticides.
In this sense, following the problems of tiger mosquitoes, SEO/BirdLife regrets the “lack of environmental approaches“Public Administrations” in the search for effective solutions to the problems caused by the imbalances of nature.
No to fumigations
In this sense, SEO/BirdLife warned that fighting an insect with these characteristics with fumigations “will not be able to eradicate it, with the added danger that the Tiger mosquito can develop immunity to insecticides“.
He considers it “a great contradiction” that in many municipalities of Extremadura where the tiger mosquito is currently being fought “The mass destruction of nests of swallows, house martins and swifts has been authorizedtheir main natural predators, only because they generate excrement under their colonies.
Therefore, and to avoid this inconvenience, the SEO/BirdLife delegate in Extremadura, Marcelino Cardalliaguet, emphasizes that “there are effective alternatives such as Suitable trays and gutters which considerably reduce dirt on facades and streets without the need to destroy the nests, which are also protected by law.
Ban plantations
In the case of Andalusia and the West Nile virus, the Ecologists in Action proposal drew attention to the fact that the solution The idea was to ban rice planting.
For Ecologists in Action “it is indisputable that the main source of reproduction of the mosquito carrying the virus in the Bajo Guadalquivir and other areas of the province of Cádiz “It is found in flooded areas, among which rice fields stand out.”
The entity also considers that it did not act in time or use adequate and early prevention mechanisms. Among the recommendations is that of treating with “the larvicide Bti all flooded area near built-up areas and at the right timeor rice planting is prohibited around the aforementioned cores, with a safety radius.
Harmless treatments
“Bti has been proven to be a very effective and harmless treatment for vertebrate fauna“We therefore regret that its application was not carried out on time, apparently due to the lack of coordination between rice farmers and the Administration,” laments the environmental organization.
Furthermore, they state that “the most urgent thing is to enable public and private spaces to have structures that They facilitate the nesting of swifts, swallows and martins and fill them with shelters for bats.which should not be the exception, but the norm”, in the case of measures already in place.
They also bet on promote “species that stop the proliferation of the virus”like “dogs, cats, horses, chickens, pigeons, which are species that are a dead end for the proliferation of the virus, they simply cannot replicate there” despite mosquito bites.
