At first, I felt a lot of surprises and some disbelief. We had been working for years on the diversity and ecology of mosquitoes in this municipality and we had never detected this species. Entomologist Pedro M. Alarcon-Elbal made this unexpected finding in the. The Spanish scientist an expert in vector-borne diseases is a professor of Tropical Medicine and Global Health at the Universidad Iberoamericana in Santo Domingo. What Alarcon-Elbal and his colleagues found in October 2019 was the Aedes vittatus mosquito known in other regions of the planet but not registered in the American continent.
Scientific studies in the last four months detailed the discovery in Dominican territory, as well as another discovery made by US scientists at the Guantanamo Naval Base in Cuba. The presence of Aedes vittatus in America raised alarm among researchers. Although the vectorial capacity of Ae. vittatus has not been studied in-depth, it is known that within its native range it plays an important role in the maintenance and transmission of various viruses such as yellow fever, dengue, chikungunya, and the Z ika, explained Alarcon-Elba.
Monitor the impact of mosquitoes such as Ae. vittatus is essential. About 700 million people in the world contract mosquito-borne diseases each year and these diseases cause about a million deaths annually according to the World Mosquito Program, a global initiative. we review the first findings of Ae. vittatus in America its implications for health, and the main hypothesis about a great mystery how did this mosquito reach the American continent? The usual home of Ae. vittatus. This species lives both in the wild and in domestic environments in Africa tropical Asia and southern Europe, where it feeds on humans and other vertebrates Alarcon-Elbal explained.
The mosquito shows a preference for reproducing in natural reservoirs such as wells, tree holes, bamboo trunks, or animal footprints although it shows considerable ecological plasticity that also allows it to exploit a wide range of artificial containers more typical of the domestic environment, such as boats. buckets, cans, or used tires, among others. One of the countries where the mosquito has been present for decades in Spain, where the presence of the species has been reported in 11 provinces belonging to the autonomous communities of Catalonia, the Valencian Community, Castilla y Le
Castilla-La Mancha, Extremadura, and Andalusia noted the scientist. It is known that within its native range, Ae. vittatus plays an important role in the maintenance and transmission of viruses such as yellow fever dengue, chikungunya and Zika, said Alarcon-Elba. Aedes vitttatus is well distributed in various European countries in the Mediterranean basin, so it is a species that probably has been with us all our, however, it is considered that the species has a low risk of disease transmission in Spain given that these viruses are not found indigenously in the territory. But the risk should not be underestimated and more studies are needed to better understand different aspects, such as their distribution and behavior. The find in this detection in Dominican territory occurred in Jarabacoa, a mountainous municipality located in the center of the country.
It was something totally unexpected. We were conducting a routine inspection of mosquito breeding sites in a house in Jarabacoa when we noticed the presence of some adult females that were trying to bite us insistently said Alarcon-Elba. We captured some individuals with an entomological aspirator while they were trying to bite us and then we observed them with a stereomicroscope, which is something we do regularly.
At first, we were puzzled by what we saw because it did not correspond to any of the species that we have cataloged in the municipality. The adults of Ae. vittatus has a dark thorax on which six spots or circular white spots stand out giving them a mottled appearance. Adults of this species have a characteristic scale pattern at the thorax level that makes them easily distinguishable from other mosquito species explained Alarcón-Elba.The adults of Ae. vittatus has a dark thorax on which six spots or circular white spots stand out, giving it a mottled appearance that together with other less apparent morphological characteristics, led us to the morphological confirmation of the species. Later, furthermore, this identification was reconfirmed by molecular techniques.
DESPITE THE SCIENTIST’S INITIAL DISBELIEF, THE RESULTS WERE CLEAR.
The initial finding and the subsequent systematic study did not cast any doubt we had detected for the first time the presence of this species not only in the Dominican Republic but in the Americas. I felt a mixture of satisfaction for the great importance of the finding itself and at the same time concern for the health repercussions that may arise from the presence of this mosquito in the future. The find at Guantanamo
The first study that confirmed the presence of Ae. vittatus in America was published by Alarcon-Elbal and his colleagues in August 2020.
American scientists published a study this year detailing a finding of Ae. vittatus at the Guantanamo Naval Base in June 2019 even before the October detection in the Dominican Republic. This is something very common in science. Apparently, fellow entomologists from the Guantanamo Naval Base had detected this species a few months before we did it in the Dominican Republic. However we the genetic sequences and the article in that we showed the scientific community the details of our research several months before them and of course, totally oblivious to their discovery.
But regardless of who found the mosquito first or who published the finding more quickly, the important thing is that both groups detected the presence of an exotic species in two neighboring Caribbean countries almost simultaneously, and not just any species, but one that has the potential to change the epidemiological panorama of certain diseases, such as dengue, shortly. The discovery at the Guantánamo Naval Base was made by entomologist Benedict Pagac, from the United States Army’s bio-surveillance program.
THE US MILITARY HAS A LONG TRADITION OF MOSQUITO RESEARCH.
More soldiers died in the Vietnam War from mosquito-borne diseases than from bullets or fighting scientist Yvonne Linton told journalist Jacob Kushner for a future story. Linton is a vector expert with the Walter Reed Biosystematics Unit, a collaboration between the US Army and the Smithsonian Institution-National Museum of Natural History in Washington.
Linton identifies the mosquitoes found and assesses the risks they pose to US soldiers. I knew the Ae. vittatus find was not a good thing, Linton told. I knew it was invasive and that it is a very effective vector for dengue, chikungunya, Zika, and yellow fever. How the mosquito got to America is one of the first questions we asked ourselves, Alarcon-Elbal told.
The scientist and his colleagues suspect that the used tire trade may have been the gateway.Many species belonging to the genus Aedes use these tires to lay their eggs, as they provide them with a place where water accumulates regularly and where adults are protected from the environment and direct sunlight. Eggs have the ability to resist desiccation for long periods of time (even months) explained Alarcon-Elba.In fact, since the mid-1980s the importance of the tire trade-in dispersing certain species of mosquitoes, such as Aedes albopictus, has been studied. The Aedes albopictus, the Asian tiger mosquito, was a known vector of dengue, yellow fever, and chikungunya in Southeast Asia. At the end of the 70s, some eggs of this species were transported to Albania in a shipment of used tires. And from there the mosquito-spread throughout Europe and to other regions of the world.
ALARCON-GLOBAL BELIEVES THAT SOMETHING SIMILAR MAY HAVE HAPPENED WITH AE.
We believe that the used tire trade has once again been how this mosquito has entered the Americas. That is, through the importation of used tires with Aedes vittatus eggs that have subsequently hatched in the place of destination of said merchandise, as a result of having been stored outdoors and subsequently rehydrated with rainwater.
The genetic study of the specimens found in the Dominican Republic and its subsequent comparison with other genetic studies carried out on this same species allowed the scientists to determine that the mosquitoes found probably came from India.Possible spread.If Ae. vittatus is in the Dominican Republic, it is definitely in Haiti, Linton told. We assume that it is also in Jamaica, Puerto Rico, and could already be in Florida he added. For Alarcon-Elbal there is no doubt that the environmental and climatic conditions are favorable for the establishment of this exotic species in other countries of the insular Caribbean, and even other American countries.
Moreover, together with some Cuban colleagues, we have just detected the species also in the central-eastern region of Cuba, in the province of Camagüey, almost 400 km from the Guantánamo Naval Base. We have many questions that we need to answer about this mosquito, and working side by side with Cuban entomologists will be of great help given their vast experience in the fields of medical entomology and vector-borne diseases.
The climate change, to the winters, cause less prolonged and intense, can also help in the dispersal of many mosquito species from warmer areas to high latitudes. A good example of this is the establishment of the Aedes albopictus species in some Central European countries, where winters are much colder than in the countries of the Mediterranean basin.
What Steps Can Be Taken
Measures such as spraying chemicals or emptying containers of standing water are often used to combat mosquitoes. Biovigilance can help limit the spread of vectors, which can occur very quickly, as happened in 2013 during the Latin American outbreak of chikungunya, a mosquito-borne viral disease that causes fever and joint pain.
In December 2013, the first case of local transmission of chikungunya was identified in the American continent, in the Caribbean. By August 2014, the Pan American Health Organization reported more than 600,000 cases in nearly 30 countries in the region. For Alarcón-Elbal, the finding of Ae. vittatus in the American continent “has significant implications for the ecosystem and human health, in the latter case if its ability to transmit pathogens in the Caribbean is proven.
Without a doubt, this introduction may represent a change in the epidemiological scenario of endemic diseases such as dengue, adding, if possible, a further degree of complexity in its control. The increased movement of people and goods has facilitated the geographical spread of pathogens and vectors in recent decades. This will be a recurring problem in the future. So much so that I consider that it is not necessary to go to the future, but to take a look at this very serious situation in which we have lived for more than a year with the current pandemic.
The scientist assures that it is essential to adopt a One Health or One Health strategy, in which experts in animal health and human health work together. The time has come for veterinary medical entomologists or One Health entomologists to be included in the preventive medicine teams of the island Caribbean countries, Alarcon-Elbal told. The cost of vector disease prevention is often less than the cost of control after an epidemic starts.
If we want to have the tools and the right human team to deal with these types of problems in the future investment in science research and higher education must be increased urgently. If not we will only arrive in time to lament.