00:00In September, Portugal released 30,000 mosquitoes in Lisbon.
00:04But these were no ordinary mosquitoes.
00:06They were specially treated sterile males released into the environment
00:09as part of an effort to reduce the population of the Asian tiger mosquito.
00:14They were just irradiated with radiation, so they became sterile.
00:20And when female mosquitoes try to mate with a sterile male mosquito,
00:25they don't give an offspring and that decreases the population of mosquitoes.
00:31It's a technique that Portugal has now used for a second time
00:34as authorities try to prevent the spread of mosquito-borne diseases.
00:38What we are fighting against is that we become an endemic country
00:42of diseases that can be transmitted through mosquito bites.
00:46The Asian tiger mosquito has become an increasingly important public health concern in Europe
00:50as it can carry viruses responsible for diseases such as dengue,
00:53chikanguia, and Zika.
00:56With millions of people traveling between Europe and countries where these viruses circulate,
01:00the opportunities for introduction are growing.
01:02The problem is that a lot of people are coming from their vacation back to Europe,
01:07from Thailand or Brazil or places where we have these tropical diseases,
01:11and they bring those viruses with them.
01:14And then they get bitten in Barcelona, in Madrid, in Milan or Rome
01:19somewhere where those mosquitoes are currently present,
01:22and they get bitten by a local mosquito,
01:24and that local mosquito bites someone else and infects someone else,
01:29and then you have a local outbreak.
01:31And we have seen an exponential increase of these types of cases.
01:36They're called arbovirus outbreaks, or these dengue outbreaks or chikanguia outbreaks.
01:41These are tropical diseases that we suddenly see increasing dramatically.
01:45This year, by the end of October, 76 locally acquired cases of dengue were reported in Italy
01:51and eight in France.
01:52That's more than twice as many as last year,
01:54when 35 cases were recorded in France, Italy and Portugal.
01:57It could potentially go from this sporadic event that happened once in a while,
02:02that suddenly we see a situation where dengue is a persistent problem.
02:07It becomes endemic, where it is present in southern European countries,
02:12and that is of concern. We don't want that to happen.
02:15And the mosquito itself is continuing to move.
02:18The Asian tiger mosquito does not need to fly hundreds of kilometers to expand its territory.
02:22In fact, it typically travels only a few hundred meters on its own.
02:26But it has found another way to move, by hitchhiking.
02:29They can hitchhike. So they get into a car, and then they travel in the car.
02:34This has been documented. So they go to certain stations,
02:38and they examine the cars, and they see that there are mosquitoes in the car.
02:42And then they go to the next gas station stop, and that's where the mosquitoes are.
02:47So they expand on transportation corridors.
02:51You can see how they expand along those highways.
02:55And that's exactly what has happened.
02:57This mosquito, the Asian tiger mosquito, is moving something like 60 kilometers a year further north.
03:05And we have seen, in fact, that these outbreaks that I mentioned earlier,
03:09they're moving even faster than the mosquito at 120 kilometers a year.
03:14They're coming later, but they're moving faster.
03:17And we can see that that puts every year 50 million people at risk.
03:24That means more people could be exposed to diseases that local doctors are not necessarily used to diagnosing.
03:29You have people that come in to a clinic, and they say, oh, I don't feel good.
03:34And then the first thing that the physician tends to do is, have you been abroad?
03:38But often you get an infection even if you haven't been abroad.
03:42And then how can they figure out that these type of weird symptoms that they have never seen before
03:47could be a potential tropical disease?
03:50Once a mosquito is established, it is there to stay.
03:52That's why the European Union's Health Emergency Preparedness and Response Authority, known as HERA,
03:58is investing in new ways to prepare for mosquito-borne diseases.
04:02We have just funded for more than 10 million euros the development of new diagnostics,
04:07so that when you go to your doctor and you have some symptoms like fever,
04:11it's treated well because the doctor understands what he's facing.
04:17So he will know that it is dengue or West Nile virus, and he will know what to do.
04:23Of course, we are also missing the right medicine to treat these new diseases that are coming to Europe,
04:29and that's why we are funding some researchers to develop new medicines, new therapeutics, antivirals,
04:38but we are also funding research for development of new vaccines.
04:43The vaccine, for instance, on chikungunya that has been just released last year was also funded by HERA.
04:49Another important part of the strategy is surveillance.
04:52One of the tools being explored is wastewater monitoring.
04:56The aim is to monitor international entry points, including major airports,
05:00where wastewater samples could help identify pathogens arriving from other parts of the world.
05:04Before the doctors could see with a patient that there was a new variant, we could detect it in the
05:10water.
05:11And now we are expanding the list of pathogens that we are monitoring, including, for instance, dengue.
05:19You can see if dengue is spreading in Europe through wastewater surveillance.
05:24But there are limitations.
05:26Finding traces of a virus in wastewater does not necessarily mean that there is a local transmission.
05:31It's great for capturing trends.
05:35If we know that infectious disease is rising like flu, COVID, but we are still on the pilot phase,
05:43and we are still learning how to interpret this thing.
05:47I will give you an example.
05:50We don't have local transmission of dengue in Portugal.
05:54We know that very sure.
05:55We have a very strong surveillance system.
05:58But sometimes this wastewater surveillance, I'm giving a fictional example,
06:03can pick up a disease that we know is not circulating in the community just because we imported the case.
06:09And that case was somehow picked up.
06:12And controlling the mosquito population remains just as important.
06:16And there are lots of different ways we can do that.
06:18For example, we can have aerial insecticide nets in the house that scare the mosquitoes away.
06:28So there are certain nets that you can put up and mosquitoes don't dare get into the house.
06:31You can potentially spray indoors, indoor residual spraying where the mosquitoes then sit down on the wall
06:38and they die and they can't transmit the disease.
06:41You can eliminate standing water where the mosquitoes engage.
06:46For example, a lot of great work has been done in Nicaragua where they teach people that if you have
06:51standing water
06:53and you see a little worm in that water, that is not a worm.
06:58That's a larvae.
06:59And that larvae will hatch to become a mosquito.
07:02And that is a problem for public health.
07:04So you need to tell people that these bowls of water, they need to be emptied and they need to
07:09be cleaned
07:09because the eggs are stuck to the surface of the bowl.
07:13For now, Europe is still dealing mainly with important infections and sporadic local outbreaks.
07:18But a combination of international travel, changing climatic conditions
07:22and the continued spread of invasive mosquito species is creating new opportunities for these diseases to take hold.
