Over 200,000 mosquitoes Aedes aegypti males infected with the Wolbachia bacteria were released today in neighborhoods of Ponce, as part of what was the first step of the program that seeks to control that dangerous species of mosquito that transmits the dengue, he chikungunya and the zika.
In the next few days, explained the doctor Marianyoly Ortiz Ortiz, associate director of the Vector Control Unit, hundreds of thousands more mosquitoes will be released, once they interact and reproduce with females not infected with Wolbachia, they will cause those females to produce offspring that will not be able to survive, thus leading to an eventual reduction in the amount of Aedes aegypti in the environment.
And before anyone is alarmed because millions of copies of the annoying and harmful insect are being released, Know that you probably don’t even realize that this is happening, because if anything, the most you would notice would be a possible slight increase in the presence of mosquitoes, which, as they are males, will not even bite you, since they are the females of the species. that bite humans.
“Wolbachia is a bacterium that is found in nature in more than 60% of insects, but it is not found in Aedes agypti. When placed in the male Aedes agypti, and it mates with a female that does not have Wolbachia, it causes the female to lay eggs that are not viable. This means that mosquitoes are not born, so the mosquito population is gradually reducing, “said Ortiz, adding that it can be understood as if he sterilized the female and therefore no new mosquitoes are born, and the mosquito population drops. as the mosquitoes already in the environment die of natural causes.
“The male does not sting. So it does not pose a risk to people. Neither is the bacteria going to be passing to the female and then the female can pass the bacteria to us. It is that they are not compatible because one has the bacteria and the other does not, and that causes them to be not compatible and then those eggs are not viable “, Ortiz explained, adding that the female will continue to behave in a habitual way, she will continue laying eggs, “but no mosquito will come out of those eggs.”
The doctor in Environmental Sciences and Microbiology explained that today was the first release, of just over 200,000 mosquitoes in some communities, “and we are going to increase throughout the week the number of areas where we are going to be releasing, and in total, at the end of the week, we will have released 1.5 million mosquitoes ”.
Ortiz added that no one should imagine that they are going to see a cloud of mosquitoes when they are released from a bus, since that 1.5 million are released during a week, and also the releases are not at a particular point, but hundreds of mosquitoes at each point as the bus moves through the areas where they will be released.
“You can hardly see when we release them, because they are tiny and hundreds of mosquitoes come out at the same time and are distributed in the environment”, he described, clarifying that some people could, depending on where they live, feel an increase in mosquitoes around them, “because the male mosquito, which does not bite, will be looking for the female, and the female will be around people ”.
But maybe not even that. It is not something that we have the expectation that people are going to notice a drastic difference, and if they did, we urge them not to worry, they are male mosquitoes, they will not bite, they will not be passing the bacteria and do not pose any risk to them “he insisted.
The doctor also explained that, as a fundamental part of the project, people were consulted about the area where the mosquitoes with Wolbachia would be released, they were explained what it was about, and they were asked if they agreed or not with the release of mosquitoes . Before today’s release, the doctor clarified, they went house to house to all the areas that would be impacted by the project, and they interviewed more than 2,500 people, and “84% support the technique. There was 11% who indicated they were neutral, or unaware, or did not have an opinion. And only 4% indicated that they did not support it. “
He added that this area of Ponce was chosen because it is the municipality with the highest incidence of dengue cases in recent years.
“People worry and tell us, but how are they going to add more mosquitoes, when there are so many already. But the reality is that, little by little, although at the beginning they may notice an increase, little by little they will notice that reduction. And that is what we hope ”Ortiz stressed, adding that they will be releasing mosquitoes in the Ponce area until December.
The scientist recalled that Aedes aegypti It is the only vector that we have on the island actively transmitting diseases, and it transmits dengue (in its four variants), Zika and Chikungunya, diseases that, in some cases, cause severe damage to people and sometimes can even be mortals. In addition to the harm to people and deaths, it is estimated that dengue epidemics have left over $ 40 million in economic losses in the last decade.
He commented that we continue to have cases of dengue in Puerto Rico, and recalled that we are in the middle of a pandemic of coronavirus COVID-19, “and we do not want these dengue cases to continue increasing. They can be confused between dengue and coronavirus, because they have some symptoms that are sometimes similar or confusing for some doctors to diagnose. So having a dengue epidemic along with the pandemic that we have now is a scenario that we don’t want to have ”.
“Part of what the project hopes to demonstrate is that, in addition to reducing the number of mosquitoes, it can demonstrate a reduction in the number of diseases transmitted by these mosquitoes. And that is what we hope, that if we reduce mosquitoes to less than 5%, that will reduce diseases, “said Ortiz.
To achieve what they hope with this pilot plan in Ponce, then they could extend the project to other parts of the Island.
“What we want to see here is logistics. These mosquitoes are being shipped from California, they have a process, it has required training for our staff, some tests to make sure they survive that trip. In other words, it has a complexity and a logistics, that we first want to see that it works “, said.
The expert clarified, in order to clear up any doubts that citizens may have, that This practice has been done in many parts of the world, and for several years now, so it is not about any type of experimentation with the people of Puerto Rico, as some have suggested.
“It has been done in other places, including the United States, so it is not that they are taking us for guinea pigs, as many people are concerned about. This has already been done in the state of Florida, it was done in Texas, it was done in California and it continues to be done in California, it is being done in Singapore, in Mexico, in Thailand, in several countries, in Australia it was one of the first places where it started. In Singapore they have been around four years since they started this project and have continued it. And it has been very successful. In those places, there has been a 78% to 95% reduction in the number of mosquitoes ”, the doctor commented.
“Here in Puerto Rico we are going to start. It will take a few months to see those results. In Singapore, for example, they started four years ago, and they started seeing results of seventy-something percent (reduction in the number of mosquitoes), and as the years went by and they were releasing more effectively, they reached that 95 %. So that is something that is going to happen gradually, and it is important that people feel comfortable, “he added.
On the other hand, he explained that the Wolbachia is not an artificial creation that has come out of some laboratory. On the contrary, “it is natural, it lives among us. The bacteria are found in other species of mosquitoes, not in Aedes aegypti, but in other species of mosquitoes, so people have probably already been bitten by mosquitoes that have Wolbachia, but not Aedes aegypti. It is something particular for this species. And that is what makes it special, because it is a technique that is aimed at that mosquito and it will not affect other species of mosquitoes, or bees, butterflies or other insects. And that is very important ”.
He added that it is not that they are creating a new mosquito in a laboratory, nor that they are doing any genetic modification, since the process begins with the collection of mosquito eggs in the environment, which are then taken to the laboratory and crossed with females that have Wolbachia, and the offspring of that cross have Wolbachia, “and those are then what we use.” She explained that females can pass the bacteria, but males cannot pass it to either the female or their children.
He added that they are sure that these are male mosquitoes, because in the laboratory, during the pupal stage, the females are larger than the male, and using a filter, about 95% of the females can be separated. Once they are adults, there are other characteristics, the antennas, the shape of the body, which allows the remaining 5% to be separated. “The possibility of a female sneaking in is very, very remote, it is one in 840 million, and that would have no effect on nature.”
And even if it were that extremely remote case, “and a female bites you, the bacteria will not pass you, because the Wolbachia is very large and does not pass through the beak, the proboscis, which is what the female bites with” .
The bacterium also does not pass to animals that feed on the mosquito, such as birds, bats or spiders, because “the bacterium dies with the mosquito, because it lives and depends on that mosquito, and it lives in particular cells. So it doesn’t happen to humans or other types of animals. “
On some people’s questions about why not use fumigation methods to end the Aedes aegypti, Ortiz stressed that “the reality is that spraying (or spraying) no longer works. We have done tests and it has been demonstrated by the (Vector Control) Unit and the CDC (Center for Disease Control and Prevention) that the mosquito Aedes aegypti When you expose it to these insecticides that are commonly used on trucks (fumigation), it doesn’t die, you don’t do anything to it, the impact is minimal. So we are adding a chemical to the environment that is not really being effective. “
“That (fumigation) could create perhaps even a false idea of protection, because Aedes aegypti does not kill you, but maybe other types of mosquitoes, bees, butterflies, and then you feel less flying insects, you feel fewer mosquitoes, but really the Aedes aegypti, which is the one that transmits diseases, is not killing it, “said Ortiz, highlighting that precisely this is one of the reasons why they are looking for other techniques to combat Aedes aegypti, such as this one from Wolbachia, which “is effective, eco-friendly, specific, does not attack other organisms, such as bees that are so important.”
Last but not least, the doctor reminded the population that, regardless of this project, people should not put aside efforts to control mosquito breeding sites.
“We are looking for these methods and trying to control the mosquito in the best way, but the role of the citizen has to continue. We have to continue eliminating breeding sites, because that is the best way to eliminate that mosquito. We have to protect ourselves and use repellent when we are in places that we know are exposed to the bite of the mosquito. That is extremely important. In particular, we do not want the people of Ponce to be careless, because we are starting now, and it will take months for us to see a reduction ”, he insisted.