Why Dangerous Countries Are A Danger: An American Entomologist Explains!

If you go on holiday in an exotic country, you should find out something about the diseases that you can get because of mosquito bites. Because mosquitoes currently endanger a large proportion of the world's population. Every year, over 750 die. 000 people (including many children) from mosquito-borne diseases. Epidemics of diseases such as Zika, malaria, West Nile virus, yellow fever, chikungunya, dengue fever are increasing all over the globe. And even if it's not a furious animal, the mosquito is the most deadly animal in the world.

Learn from the interview below with Bart Knols, an American entomologist speculating in ways to prevent mosquito-borne malaria, what efforts are being made to stop the large number of deaths caused by these seemingly harmless animals. Each of us has a life story about someone or something that has influenced us to choose a particular career. your. Why did you decide to devote so much time to extermination of mosquitoes? . During my studies, I primarily focus not on mosquitoes, but on flies that send sleep to Africa.

But at one point, I realized that the impact of mosquitoes on people around the world is far more dramatic than that of bite flies. As a result, I decided to make a career change and from bite to turn to mosquitoes. It's 25 years since I studied. From these 25 years, I lived 11 years in East and South Africa and during that time I myself have malaria nine times. I was on the brink of losing my wife because of malaria and I saw too many kids around me killed by this disease.

So if someone wants a solid motivation to do something against mosquitoes, I suggest that they contract such diseases. Guaranteed, will remain strongly motivated for the rest of your life, I tell you for sure! . K. : Several approaches are currently being tested around the world, but the most interesting ones are biotechnology and molecular technology, where we try to modify the mosquito genome so that they can not transmit certain diseases like malaria or fever . We are talking about new technologies that have begun to be used in the last 4-5 years.

One of the most widespread currently is the CRISPR / Cas system, through which we can operate very specific gene modifications, ie modifications of the mosquito genome. I believe that the progress made in this area is extraordinary. Already in the US, in California, they managed to modify a mosquito so far that it can not transmit malaria anymore, and the modification was made with this CRISPR / Cas. Preparations are already being made in the field in Africa in this direction; . We hope that these new systems will make mosquito populations incapable of transmitting diseases like malaria.

The result would be the spectacular decrease in the number of infected people - and that is only due to biotechnology. Could we control the process by which these genetically modified insects reach more than normal? . B. K. : Yes.

There are two ways to do this. Either we have what we call a gene-based system: we introduce a new gene to a mosquito population, knowing that the gene will then be inherited by the next generation. Thus, over time, more and more mosquitoes will emerge with that genetic modification and will no longer be able to transmit disease. And the second is to try to reduce mosquito populations using mosquito-inducing sterility. And this method is presented in the documentary.

Currently, Brazil is released into the natural environment by Oxitec mosquitoes. They have a gene that will eventually induce a deadly reaction. In other words, the mosquitoes who have this gene will get to die because of it. This is an alternative control method. We have two possible approaches: the first is to modify a mosquito's gene to get individuals who can no longer transmit diseases.

And the second is to release mosquitoes in the natural environment that compete with the wilderness and make them sinking vertiginously - so ultimately end up with fewer mosquitoes in the wild, meaning fewer transmissible agents . Most malaria cases occur in Africa. But what disease do you think is a serious problem for European countries? . K. : In the past, there were also countries in Europe where malaria was a major problem, but now this disease has been completely eliminated from the European Union.

We are no longer confronted with problems caused by malaria, but there remains the risk of other viral diseases. Even in Croatia, there have recently been cases of dengue fever, which is a viral disease transmitted by mosquitoes. In my opinion, the problems we will be confronted in the near future will mostly be related to the viruses transmitted by the mosquito sting. If we are talking about the Mediterranean region, that is South Eastern Europe, then the big problem is the West Nile virus, which is likely to remain one of the major problems in the area, as it is already in southern Europe, in Greece. A few years ago, over 100 such cases were recorded.

So the West Nile virus is already present in the area and is likely to begin spreading northwards, and in the rest of Europe. Climate change will play a very important role because the weather is getting warmer, so the environment is becoming more propitious for mosquitoes and thus increases the risk of transmission of these diseases through mosquito bites. What can ordinary people do to fight these diseases? . These small water meshes are the source of mosquito problems. Any small plastic container around the house, like those under flower pots, all the places where a small water eye can be gathered for a few days, up to a week, is a possible breeding ground for mosquitoes, .

If each of us takes care to clean up all the garbage and all the small plastic containers that are lying around the house and around the house, we can say that we have already taken an important step in keeping these diseases under control. What is the best way to fight mosquitoes? . K. : In my opinion, the only way to successfully eliminate diseases such as malaria or Zika would be to choose an integrated approach. There is no so-called Ideally, we should opt for a clever integration of several methods, used at the same time, to have the strongest impact on the mosquito problem and thus the transmission of these diseases.

Take, for example, malaria. You're wondering if we should just thank DDT to solve the problem? . It's not enough just to use DDT. It is good to use mosquito nets too, so people can sleep under these nets, sheltered by insects. It is good to let people know as much as possible in order to know that if a child makes a big fever, he must immediately take measures and take him to a clinic.

In addition, it is good to make sure that when the child reaches the clinic, a correct diagnosis is made and there are the necessary tools to determine whether or not malaria. And finally, if you are diagnosed with malaria, it is important to make sure that the patient has access to the best possible medication to be treated and make sure that the parasite is removed from his body. In conclusion, it is best to use a full set of tools, an integrated package that will give us the highest chances of success. If we look at all the countries in the world where malaria has been successfully eliminated - because there are already over 100 such countries - we see that this success has been achieved by implementing a package of solutions through an integrated approach. It has never been a single tool that tried to solve the problem of malaria or any other mosquito-transmitted disease.

The key word here is But those listed so far are not the only tools available. There are others and, in addition, they are constantly working on developing new solutions. Personally, I am very inclined to the elimination of chemical substances like the DDT you mentioned for a very important reason: we always have resistance problems because the mosquitoes develop their resistance to chemicals. Instead, if we use biological insecticides, then the resistance problems are much smaller or even totally absent. Why? .

So I think that in the next five to ten years we will see a clearer change in the methods and more and more from chemical control to biological control. Is it possible to create an infallible repellent to put on our skin and smell so ugly that it does not bite our mosquitoes anymore? . K. : In the field of repellents, there are products that are currently being developed, but we do not have systemic repellents, so there is no product to eat and so some compounds appear to make my skin less appealing to mosquitoes. In fact, some people are more attractive than others for mosquitoes - although that depends on the mosquito species we are talking about.

In other words, if you are appealing to mosquitoes living in Russia, that does not mean that you will also automatically be attracted to mosquitoes from Australia or Bolivia. Depends greatly on the species of mosquitoes you interact with. DEET is a chemical repellent used by 200 million people worldwide every year and continues to be a hopeful ally in the way mosquitoes keep us away. But we do not know exactly how such repellents work. As far as we know, DEET molecules block receptors on mosquito antennas, so that insects can no longer identify a possible human host.

If we go further and talk about systemic insecticides, there are some interesting developments in this area - and here I refer to ivermectin, a substance that was used in the veterinary sector. If ivermectin is administered to a man who is then stung by a mosquito feeding on her blood, the mosquito will live less and will produce fewer eggs, so fewer offspring. As a must, we can have an impact on the transmission of these diseases if we take preparations containing this substance. What is the greatest risk of mosquitoes? . K.

: The greatest risk of mosquitoes remains the diseases they transmit. If we take into account only malaria, for example, there are around 500 000 people worldwide who die of malaria each year. But as a whole, if we talk about all mosquito-borne diseases, about 750,000 people die every year around the world because of mosquito bites. So the greatest risk is the diseases the mosquitoes can convey. And of all these diseases, the most important remains, worldwide, malaria.

As far as mosquitoes are concerned, an example is the saliva they inject into the skin of the host they are stinging. Basically, when a mosquito chooses a human host to feed, he tries to take blood. The person's immune system intervenes to ensure that the blood under the skin begins to clot very quickly so that too much is not lost. But the mosquito prevents the blood clotting phenomenon because it injects the host with his saliva. This saliva contains 20 proteins that are not human proteins, so it causes a very strong reaction.

This is how we choose with a swelling on the skin that causes very, very strong itching. The problem is that both viruses and parasites in the mosquito's body come into its salivary glands. So when the mosquito feeds human blood and injects her saliva under her skin she will automatically inject parasites or viruses into her body. This is how people get infected with the diseases. You made a very courageous experiment, even with your own body, when you walked completely naked into a mosquito room.

The conclusion was that the feet of the feet attract the most mosquitoes because of the smell. But what about the other parts of our body? . A study published in the early 1950s in Uganda followed a particular mosquito species that stung naked children. Those mosquitoes had a clear preference: they were facing the host's face. I was amazed at this result because I remembered the time when I was working in Africa and when the mosquitoes bite us mostly on the ankles and the foot.

As a result, we also organized an experiment in which I exposed a subject - in my case, myself - to several mosquito species and I watched which area of ​​the body she chose for each species. Indeed, it has been proven that the African malaria mosquito has a strong preference for the area of ​​the ankle and foot paw, while Malaria's Dutch mosquito prefers to stigmatize the face of the host. Further, the experiment showed us that if we changed the For example, if we deviate the exhaled air by removing it from the room through a tube, then the mosquitoes who had previously preferred to bite the subject, would suddenly begin to apply stings to the whole body. So, obviously, their original choice was related to the air exited by the person. In other words, those mosquitoes responded to the carbon dioxide in the expired air.

Further, in the case of mosquitoes biting the ankle and foot paws, we modified that preference by washing the subject's feet with a medicinal soap containing an agent that destroyed all the bacteria on the legs. So I showed clearly that in that case the mosquitoes were attracted by the smell of the subject's feet. In the end, another idea came to us: what is very much like the smell of human feet? . And we found that we could attract African mosquitoes who transmit malaria using a piece of Limburger cheese. Why did this work? .

So we managed to attract this African mosquito using dairy products. What about genetic engineering? . B. K. : Moreover, it has already reached the stage where genetically modified mosquitoes are released on the ground.

We are talking about Brazil, a country that releases genetically engineered mosquitoes to control the spread of the dengue fever virus. As shown in the documentary, it appears that using this method can reduce mosquito populations by over 80%. It's a very interesting thing. However, the issue of maintaining this phenomenon also arises in the case of larger scale application. There is currently a scientific test on a small town with 5000 inhabitants.

All good and beautiful, but Brazil is an extremely big country. How will this technology be extended to large areas of Central and South America? . And such a problem is very complicated and very difficult to solve. What are good mosquitoes for? . K.

: The mosquitoes also have their role in nature. In some ecosystems, it even plays an important role - and I do not refer here to the adult mosquitoes that make people stigmatized, but mostly to mosquitoes in the larval stage. These larvae provide food for many species of fish, amphibians and other aquatic organisms. And in some ecosystems in the world, the total biomass of larvae mosquitoes is very high - for example, in some marshland systems such as those in the Everglades area of ​​Florida. If we completely eliminate mosquitoes from these ecosystems, it is likely that the phenomenon would have a strong impact on the ecosystem as a whole.

In most areas of the world, however, we can see that the total biomass of mosquito larvae is very limited. A small plastic container lying behind a house somewhere in Rio de Janeiro can only collect a small amount of water, so the biodiversity contained in that water will be just as small. In conclusion, the problem depends on where you are and the total size of mosquito biomass in that area. On July 6, starting at 21 o'clock. 00, Discovery Channel will broadcast the Mosquito documentary for the first time, drawing attention to the most powerful agent of death in the modern history of mankind.

In the narrative of Oscar nominee actor Jeremy Renn, the film chronicles the increasingly serious danger this insect poses, revealing the potentially deadly consequences of the phenomenon in the absence of a worldwide effort. .