What will be the future of mosquitoes, the major killers of humans, around 2030?

What will be the future of mosquitoes, the major killers of humans, around 2030?

It follows a selection of my tweets on What will be the future of mosquitoes, the major killers of humans, around 2030? which is part of a larger presentation Climate change and the Zika virus and other mosquito-borne diseases. The tweets are taken from my Twitter site:  @pablorodas  

You will find other sequences of this presentation here in my Linkedin, and if your institution is deeply interested in the topic, I am announcing today a  90 minutes conference, to be delivered from now on and for some weeks in any country in Europe.

Will mosquitoes and their diseases expand around 2030? No? Some? A lot? They’ll benefit from climate change but the answer is difficult.

The problem is that there’re many "guys" involved: diseases, mosquitoes, we, and often animals that serve as reservoirs of the diseases.

Besides to forecast mosquito-borne diseases, you need plenty of variables: climate, ecology, vector (mosquito), demographic, etc. etc.

Since mosquitoes have been the main killers in human history, there's a great interest in knowing what will climate change bring.

In other words, since mosquitoes' criminal reputation is high, many scientists have analyzed what climate change will bring. We’ll see that here.  

Of the about 3,000 of species of mosquitoes, just a handful bites humans, and two species are both dangerous and have expanded to many places.

Those two terrible and “global” mosquitoes are: Aedes aegypti and Aedes albopictus. Scientists have focused their sophisticated models on both.

Aedes aegypti is an old fellow that has killed hundreds of millions with malaria and yellow fever. Aedes albopictus is a menacing new guy!

Those two mosquitoes behave like mafia: they’ve divided their territories. The first prefers the tropical world, and the second the temperate one!

The new guy, Aedes albopictus, traveled from Asia to the US and Europe in a smart way: imported used tires from Japan, as mosquitoes' eggs.

The key secret of Aedes albopictus is that its eggs can diapause: if laid in early autumn, they hatch until...next spring! Survive the winter!

That’s the main danger in the US, Europe and other temperate places with climate change: if the eggs overwinter, the mosquitoes have... settled!

Let’s see know the main scientific findings about climate change and those two terrible fellows: Aedes aegypti and Aedes albopictus.

Climate change will increase 1) temperature, 2) precipitation (in some places droughts) and 3) humidity, three things mosquitoes love!

The higher the temperature, the more Aedes albopictus mosquitoes will advance in temperate places like US and Europe.

The higher the temperature, the longer the yearly "hunting-human season" for mosquitoes, and the longer the period of viral transmission.

The higher the temperature, the farther mosquitoes will expand in latitude and altitude in the world!

The higher the temperature, the faster the female mosquitoes will digest the blood, the more meals they'll need, and the more they'll bite!

The higher the temperature, the faster the oviposition cycle, which means... more sex and more eggs!

The higher the precipitation, the denser the vegetation, and the higher the number of breeding sites for mosquitoes, but...

… but if precipitation is too high, it may wash out the breeding sites of mosquitoes, reducing their numbers... not all benefits them!

The higher the temperature, the faster the larva of mosquitoes will mature, and the sooner they'll be biting us!

The higher the temperature, the faster the development rates of mosquitoes, and the greater the number of generations per year.

The higher the temperature, the smaller the size of mosquitoes, the more often the females need to feed, and the more they bite us, but...

… but the smaller the body size of mosquitoes, the lesser the nutrients they acquire and the shorter their lifespans. Not all favors them!

The higher the temperature, the faster viruses, bacteria, and parasites complete the extrinsic incubation inside the female mosquitoes!

Up to now I've mentioned many relations between climate change & mosquitoes, but that's not all we must look at...

The higher the urbanization, the closer people are packed, and the larger the "blood menu" for mosquitoes!

And not only urbanization, but the larger the cities, the higher the temperature, and the "better settled" the mosquitoes feel!

In megacities like NY/London/Paris, temperature could be several degrees centigrade higher than their surroundings. Mosquitoes' party!

Climate change will also increase droughts. Mosquitoes hate droughts, since high aridity may even vanish them, but...

… but what would you prefer: a) no water because of droughts or b) water and mosquitoes? The answer is obvious.

The richer the countries, the better they cope with mosquitoes (better houses, more oversight by public institutions, etc.) and the lesser diseases they suffer.

The case that´s often mention is Texas vs. the bordering Mexican states: similar armies of mosquitoes, but dengue is a problem in Mexico!

The closer you live to the vanguards of mosquitoes, the more vulnerable you're due to climate change: better to be in Oslo than in Vienna, or in Toronto than in Pittsburgh.

The lower you live in the highlands (African highlands, Andes, etc.), the more vulnerable you'll be to the armies of mosquitoes!

Here is the current environmental suitability (not future yet) of the Aedes aegypti. The closer to red... :(

Here is the current environmental suitability (not future yet) of the Aedes albopictus. The closer to red... :(

Aedes aegypti has been around for long time. Aedes albopictus came from Southeast Asia and is present now in all continents, except Antarctica… they may like penguins!

A critical fact about Aedes albopictus: its eggs have achieved a survival threshold close to -12C in the US and -10C in Europe... Scary!

The maps show: current environmental suitability. Mosquitoes may not be there yet, but conditions are propitious: if introduced, they’ll settle.

You may wonder: how mosquitoes will expand in the US, Europe and other temperate places? Each generation has a low dispersal rate (100-200 meters) since mosquitoes are weak fliers. How will they advance?

Aedes albopictus certainly arrived hidden in used tires from Japan, but now they buy a bus ticket, or jump into cars and trucks, and go in a day from Rome to Zurich, or from DC to Boston.

Up to know I've talked only about two species of mosquitoes, but there’re three more ruffians Aedes: japonicus, koreicus, triseriatus... :( ;(

Those three criminal mosquitoes live in the US already, and the first two in Europe. Not a great risk... since populations are small, but...

… but the names japonicus and koreicus explain clearly that they're used to cold weather, and have potential to expand in the US, Europe and other temperate places.

I'm sorry if I scared you with three more mafias, Aedes japonicus, Aedes koreicus, and Aedes triseriatus, as if we wouldn’t have enough with our current two: Aedes aegypti and Aedes albopictus!

The projected environmental suitability in Europe for the Aedes albopictus in 2030... with minimum climate change!!

Projected environmental suitability in US for the Aedes albopictus in 2040... with minimum climate change (left)!!

In summary, Aedes aegypti will expand in the tropics and sub-tropics and may disappear from very arid places, and Aedes albopictus will reign in most large tracts of the US, Europe and other temperate places!!

Both species of mosquitoes can transmit Zika virus. Many mosquito-borne diseases don’t have vaccines yet. It’s not easy to create vaccines: viruses, bacteria and parasites mutate and new strains appear.

And regarding the worldwide spread, I've written only about the future spread of mosquitoes, which is not equal to the spread of diseases. Not all mosquitoes are infected!

Then you'll say: let's project diseases for 2030, not the mosquitoes. Scientists have made models for tropical diseases like malaria or dengue, but...

… but to project mosquitoes-borne diseases in the US, Europe and other temperate places isn't easy. To the previous variables you need to add many more about viruses, bacteria, and parasites :(

Nobody knows how viruses, bacteria, and parasites will behave with climate change. First, mosquitoes experience genetic changes after five years… imagine how many generations of mosquitoes in only five years!

Second, nobody knows how viruses, bacteria, and parasites will mutate with climate change. New strains will come much much much faster than mosquitoes!

********************************************************************

Suggested readings:

Plenty of scientific papers, mainly produced or referred by the agencies of control disease in Europe and the US: European Centre for Disease Prevention and Control (ECDC), and Center for Disease Control (CDC).

Some of the scientific papers are the following:

W.E. Bradshaw and C.M. Holzapfel (2006) “Climate change: Evolutionary response to rapid climate change”, Science.

Fischer (2014) “Climatic suitability of Aedes albopictus in Europe referring to climate change projections: comparison of mechanistic and correlative niche modelling approaches”, Euro Surveill.

Depoortere et al. (2009) “Technical Report: Development of Aedes albopictus risk maps, European Centre for Disease Prevention and Control (ECDC).

A.K. Githeko et al. (2000) “Climate change and vector-borne diseases: a regional analysis”, World Health Organization (WHO).

C.W. Morin et at. (2013) “Climate and Dengue Transmission: Evidence and Implications”, Environ Health Perspect.

Proestos et al. (2015)“Present and future projections of habitat suitability of the Asian tiger mosquito, a vector of viral pathogens, from global climate simulation”, Phil. Trans. R. Soc. B.

Rochlin et al. (2013) “Climate change and range expansion of the Asian tiger mosquito (Aedes albopictus) in northeastern USA: Implications for public health practitioners”, PLoS ONE.

C.R. Williams et al. (2014) “Bionomic response of Aedes aegypti to two future climate change scenarios in far north Queensland, Australia: implications for dengue outbreaks”, Parasites & Vectors.

Mariângela Vieira Мариангела Виейра [She/Her]

Earth Sustainable Solutions / Agronomy Education Environment | Internacional Senior Consultant | Visionary / Rainmaker 17, 600 +

8y

Anopheles gambiae is the major transmissor of malaria. The dengue viruses are engineered and the GMO mosquitos caused the microcephalia not zika virus. The viruses dengue, chikungunya and zika came from yellow fever virus and they are very highly mutants. They can change while entering the mosquito, while entering the human body or other hosts; they mutate inside the mosquitos and inside the human body they can re-combine when they have another "cousin" viruses inside. There a lot of serious papers discussing that in serious scientificc magazines. Just search on google scholar. CDC and CoD...are not the most trustable people. The climate change is due HARRP, Chemtrails, and other engineered things.

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Kamran Rafiq

Co-Founder & Communications Director ISNTD

8y

Thanks for posting !

Fabio C.

Technical Consultant - Prof. Dr. Biologist, Entomologist, Pest Control, Vector borne diseases and Tropical medicine.

8y

Excellent! Very good work! Thanks !

Daniella Taveau 🇺🇸🇮🇱🇺🇦

Strategist | IMAGINE Leader | Artist | Coalition Builder | Problem Solver | Board Member

8y

Great article.

Salote Soqo

Global Displacement, Advocacy, Climate. Migrant, Disaster Justice, Human Rights

8y

Would you be willing to speak at a hosted webinar conference?

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