Thursday, November 7, 2019

Gone, but not forgotten


Slap!!!

That is the sound of my hand crushing the life out of the last mosquito of 2019.

The mosquitoes stayed late this year, possibly because of the wetness and lack of frost. I can’t ever recall being bitten in October before, but this year I had several late October stings.  

Now the mosquitoes finally are gone, out of sight, out of mind, until May.

It is a mistake to put them out of mind. We need to think seriously about mosquitoes and the growing health threats they present.

Our planet is warming, encouraging bugs and plants once confined to warmer southern areas to move north.  Ticks carrying Lyme disease are moving beyond their normal ranges of southwestern Ontario and have reached on the edges of Haliburton County.

Mosquitoes carrying viruses not known in northern climates also are moving north. In the past 10 years or so nine previously unknown species have been added to the list of mosquitoes found in Ontario. That list has grown to 67 different species.

West Nile virus, not seen in North America until 20 years ago, is here now. Aedes aegypti, the mosquito capable of carrying the Zika virus, was found in southwestern Ontario two years ago.

That mosquito also has been known to carry other tropical diseases such as dengue fever, chikungunya, and yellow fever.

There also has been an increase in North America of eastern equine encephalitis, Triple E, as it is sometimes called,  a once rare but deadly mosquito-borne virus. There were three confirmed Triple E deaths in Michigan this past September.

At the end of October the U.S. Centres for Disease Control reported 35 confirmed cases of Triple E this year, 10 0f them in Michigan. Thirteen of those 35 infected people died.

To northerners, mosquitoes always have been just a summer annoyance. Different species moving north are a health threat not to be taken lightly.

Just ask Timothy Winegard, a professor at Colorado Mesa University and a Canadian, originally from Sarnia. His new book, The Mosquito, documents how mosquitoes and the diseases they carry have changed world history.

He writes that mosquitoes have killed more people than any other cause of death in human history. He estimates that mosquitoes carrying disease have killed almost one half of the 108 billion humans who have lived over the past 200,000 years.

His book documents how mosquito–borne diseases such as malaria changed war outcomes, decided the fates of empires and altered human history.

“The mosquito remains the destroyer of worlds and the preeminent and globally distinguished killer of humankind,” Winegard writes in the introduction to his book.

Last year the mosquito and her diseases killed 830,000 people worldwide.

I wrote her because only female mosquitoes bite. They do so to get blood needed to grow and mature their eggs.

Female mosquitoes will bite anyone with blood, but they do have some preferences. Research shows they have a special taste for Type O blood. People with Type O are bitten more often than folks with Type A or Type B.

Also, mosquitoes have an affinity for beer drinkers, although no one seems to know why.

Pregnant women get bitten twice as often as other people. Scientists say that is because pregnant women give off 20 per cent more carbon dioxide (CO2) than the average person. CO2 and the body chemicals that are mixed with it attract mosquitoes.

These are mild preferences that science still does not completely understand. What we do know as fact is that anyone with blood in their veins is a potential victim.

Being a victim once meant simply being irritated by an itchy bump on the skin. But that is changing as more mosquitoes carrying serious disease find their way farther north.

Many people bitten and infected with West Nile or Zika might not show any symptoms, or might temporarily feel feverish with muscle weakness.

However, West Nile and Zika can have serious consequences for some people. West Nile can infect the nervous system resulting in meningitis or encephalitis and bring on long lasting paralysis similar to polio. Zika has been linked to a serious birth defect and to Guillain-Barré syndrome.

So although they are gone, we should be thinking about being more careful about mosquito protection for when they return.


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