By TIMOTHY C. WINEGARD
Saturday, August 3, 2019
Author of The Mosquito: A Human History of Our Deadliest Predator
As a tourism campaign, marketing your city as the "Mosquito Capital of the World" flies in the face of all logic. Mosquitoes are generally not a big-ticket attraction. I imagine there are not too many people who'd put a mosquito-themed vacation on their bucket list.
Nevertheless, in 1984, the buzzing town of Komarno, Man., located roughly 70 kilometres north of Winnipeg, did just that: Embracing its reputation - its name means "mosquito infested" in Ukrainian - the town proudly erected a menacing, 15foot-tall statue of a mosquito with a wingspan approaching 17 feet - the largest mosquito on the planet. While Komarno's title as the mosquito capital is unofficial, Canada garrisons the largest national contingent of the 100 trillion or more mosquitoes circling almost every inch of the globe. As a country we are, quite literally, the mosquito capital of the world.
With a vast labyrinth of rivers and lakes comprising 20 per cent of the world's fresh water (a vital ingredient for the reproduction of mosquitoes), Canada is a mosquito wonderland. In fact, the oldest mosquito fossil on record, dating to about 80 to 100 million years ago, was unearthed in Canada. From the Arctic tundra to the Great Lakes, Canada is consumed by mosquitoes.
Even the austere Arctic and its nomadic animals are not spared from being hounded and probed by hungry hordes of mosquitoes.
"There aren't a lot of animals for them to eat in the Arctic, so when they finally find one, they are ferocious," says Lauren Culler, an entomologist at Dartmouth College's Institute of Arctic Studies. "They are relentless.
They do not stop. ... You can be completely covered in a matter of seconds." Ravenous swarms literally bleed young caribou to death at a bite rate of 9,000 a minute - or by way of comparison, they can drain half the blood from an adult human in just two hours. For Canadians, and perhaps for our caribou, mosquitoes are as pervasive and generic to our culture as hockey, Tim Hortons and butter tarts.
But what we consider to be a mild, albeit infuriating, annoyance could soon have far more fatal consequences for our caribou and ourselves. A team of public-health experts writing in the Canada Communicable Disease Report recently acknowledged that "climate change is anticipated to have significant effects on Canada's endemic mosquito populations and thus on MBDs [mosquito-borne diseases]. ... The expected climate-induced changes in mosquitoes and MBDs underline the need for continued surveillance and research to ensure timely and accurate evaluation of the public health risks to Canadians. Public health professionals and clinicians need to promote awareness among Canadians of this important public health risk."
Climate change means that the diseases carried by mosquitoes (and itinerant vectoring mosquito species) are expanding their reach, penetrating more northerly ecosystems.
That statue still stands in Komarno. The tongue-in-cheek, larger-than-life tribute to our national pest could one day be seen as far more ominous.
While groundhog Wiarton Willie may predict the onset of spring, the arrival of summer is signalled by the flight of the famished female mosquito. Her buzz has been one of the most universally recognizable and aggravating sounds on Earth for more than 100 million years.
Although you heard her droning arrival, she gently lands on your ankle undetected. She conducts a tender, probing, reconnaissance, looking for a prime blood vessel. She steadies her crosshairs and zeroes in with six sophisticated needles.
She inserts two serrated mandible cutting blades and saws into your skin, while two other retractors open a passage for the proboscis, a hypodermic syringe that emerges from its protective sheath. With this straw she starts to suck your blood, immediately excreting its water while condensing its protein content. All the while, a sixth needle is pumping in saliva that contains an anticoagulant, preventing your blood from clotting at the puncture site.
This shortens her feeding time, lessening the likelihood that you feel her penetration and splat her across your ankle. The anticoagulant causes an allergic reaction, leaving an itchy bump as her parting gift. With this single bite she can also transmit one of several diseases. For the mosquito, she simply needs your blood to grow and mature her eggs.
Please don't feel singled out.
She bites everyone. This is just the nature of the beast.
Unfortunately, 85 per cent of your mosquito-seducing charm, including chemical and bacteria levels in and on your skin, your body odour, blood type and the amount of carbon dioxide you discharge, is prewired in your genetic circuit board. Although she has her favourites (type O blood, for example), she's not a finicky eater. At the end of the day, she will attack any exposed target of opportunity.
Unlike their female counterparts, male mosquitoes do not bite. Their world revolves around nectar and sex. While males will mate frequently in a lifetime, one dose of sperm is all the female needs to produce numerous batches of offspring. She stores the sperm and dispenses them piecemeal for each separate birthing of eggs. Her short moment of passion has provided one of the two necessary components for procreation. The other ingredient is your blood.
The bloodthirsty females carry an arsenal of lethal and debilitating biological weapons, including malaria, West Nile, Zika, dengue, elephantiasis (filariasis) and yellow fever, making the mosquito the planet's deadliest human predator. Researchers suggest her total body count approaches half of the 108 billion human beings who have ever lived throughout our relatively brief 200,000-year or more existence.
While statistics vary across a wide range, since 2000 the average estimated number of human deaths caused each year by the mosquito has hovered between roughly one and two million. We humans come in a distant second, responsible for 475,000 deaths, followed by snakes (50,000), dogs and sand flies (25,000 each), the tsetse fly and the assassin/kissing bug (10,000 each). The fierce killers of lore and Hollywood celebrity appear much further down our list. The crocodile is ranked No. 10 with 1,000 annual deaths. Next on the list are hippos with 500, and elephants and lions with 100 fatalities each. The much-slandered shark and wolf share the No. 15 position, killing an average of 10 people per annum.
Of course, the mosquito does not directly harm anyone. It is the diseases she transmits that cause unrivalled desolation, suffering and death. Without her, however, these sinister pathogens could not be vectored to humans. You cannot have one without the other. Imagine for a moment a world without deadly mosquitoes - or any mosquitoes for that matter. Our history and the world we know, or think we know, would be completely unrecognizable.
As the paramount historical killer of humankind, she has played a greater role in shaping our story than any other animal with which we share our global village.
Karl Marx recognized in 1852 that "men make their own history, but they do not make it as they please." The insatiable mosquito manipulated and determined our destiny, scratching her indelible mark on the modern world order.
We tend to forget that history is not the artifact of inevitability.
We can shoulder some of the blame, as humans have aided and abetted in the transmission of mosquito-borne diseases. Historically, our migration patterns, domestication of plants and animals (which are reservoirs of disease), advancements in agriculture, deforestation, climate change (natural and artificially encouraged), global wars, trade and travel have all played a part in nurturing the ideal ecologies for the proliferation of mosquitoborne illnesses. The mosquitoes and diseases that have accompanied traders, travellers, soldiers and settlers around the world have been far more lethal than any manufactured weaponry. She has decided the fates of empires and countries, razed and crippled economies and commanded the outcome of pivotal wars by laying waste to the greatest armies of her generations. From helping to orchestrate the rise and fall of the Roman Empire to operating as a sinister agent of the Columbian Exchange and the transatlantic African slave trade and reinforcing the victors of the American Revolution and the Civil War, among an accomplished résumé of other events, the mosquito has had her way with our global history. Canada did not fly under her sweeping historical radar.
During the 18th and 19th centuries, for instance, the bustling port cities of Halifax and Quebec City were home to sporadic yellow fever epidemics spread by infected sailors and stowaway mosquitoes disembarking from ships in transit from Caribbean colonies. This dreaded virus produces fever-induced delirium, jaundice owing to liver damage and bleeding from the mouth, nose and ears. Internal corrosion induces vomit of bile and blood the consistency and colour of coffee grounds, giving rise to the Spanish name for yellow fever, vómito negro (black vomit), which can be followed by coma and death. The latter might well have been the last pleading wish of many victims. To make matters worse, yellow fever was often accompanied by unbridled malaria. These toxic twins determined the fate and imperial future of Canada during the Seven Years' War.
For France, the war in Europe and the defence of her lucrative Caribbean colonies far outweighed the security of Quebec's portfolios of fish, timber and fur.
France's concerns for her Caribbean sugar, coffee and tobacco plantations, however, were costly. Within the first six months, yellow fever and malaria killed half of newly arrived French defenders deployed to Haiti, Guadeloupe, Martinique and other, smaller islands. Troops were siphoned from Quebec to these besieged outposts. As a result, Caribbean mosquitoes starved French Canada of men and munitions. The ability of French commander Marquis de Montcalm to co-ordinate any meaningful defence of Canada was stymied.
"Unseasoned" French reinforcements were continuously shovelled into and burned in the mosquito-stoked furnace of the tropics, leaving Canada exposed and vulnerable. The fragile dominion of the French over Canada came undone in September, 1759, with British Major-General James Wolfe's swift victory over Montcalm's beleaguered and outnumbered forces on the Plains of Abraham at Quebec City, paving the way for the creation of modern Canada.
In the wake of General George Washington's mosquito-broker-
ed victory during the American Revolution, some 90,000 United Empire Loyalists fled the United States for Canada to uphold personal political loyalties, escape persecution or seek asylum from some of the worst yellow fever epidemics in American history.
While these Loyalists carried British culture and convictions to Canada, they also brought malaria. Mosquitoes and their diseases do not respect international borders. In 1793, for example, the wife of John Graves Simcoe, the governor of Upper Canada and a prominent British officer during the revolution, contracted malaria in the provincial capital, Kingston. Located on the shores of Lake Ontario, the city also operated as the southern terminus for the Rideau Canal, with its point of origin in Ottawa.
In a forgotten footnote of Canadian history, malaria went on a rampage in Ottawa during the construction of the 201-kilometre-long Rideau Canal between 1826 and 1832. Each year from July through September - known to the builders as "the sickly season" - roughly 60 per cent of the work force contracted malaria. After the malaria season of 1831, chief contractor and engineer John Redpath wrote that "the exceeding unhealthiness of the place from which cause all engaged in it suffered much from lake fever and fever & ague [malaria], and it has also retarded the work for about three months each year." Redpath himself "caught the disease both the first and second year missed the third but this year had a severe attack of Lake Fever - which kept me in bed for two months and nearly two months more before I was fit for active service." Not to worry.
Redpath survived his malarial fits to create Canada's largest sugar company in 1854.
During the construction of the Rideau Canal, approximately 1,000 workers died of disease, including 500 to 600 from malaria.
At the Old Presbyterian Cemetery in Ottawa, a commemorative marker honours their sacrifice: "Buried in this cemetery are the bodies of sappers and miners who took part in the construction of the Rideau Canal at this isthmus during the years 18261832. These men laboured under appalling conditions and succumbed to malaria. Their graves remain unmarked to this day."
The canal malaria also spread to local communities, where it is believed to have killed 250 civilians.
While malaria, the historical scourge of humankind, remains our archnemesis, infecting 200300 million people a year, new mosquito-borne diseases, including West Nile and Zika, are on the move. In the United States, for example, the first domestic cases of chikungunya, dengue and Zika have been reported from Florida and Texas. Unlike all other mosquito-borne diseases, Zika can also be sexually transmitted between humans. Currently, roughly four billion people around the world are at risk from mosquitoborne diseases. Global warming has allowed the mosquito and her diseases to broaden their topographical range. As temperatures rise, disease-carrying species, usually confined to more tropical regions and lower altitudes, creep both north and south and into higher elevations.
As global warming consumes our planet, her reach is growing. Previously untapped regions, formerly free of mosquito-borne diseases, are warming up to her presence.
West Nile, for example, invaded the Western Hemisphere in 1999 through New York. Roughly 80 per cent to 90 per cent of those infected will never know and will show no symptoms. Most of the remainder will usually only experience a mild flu-like illness for a few days. But an unlucky 0.5 per cent or so will develop full-blown symptoms that can lead to swelling of the brain, paralysis, coma and death. Within a decade of its debut in the Big Apple, West Nile went viral across the United States, Southern Canada and South and Central America, announcing itself as a global disease.
The first Canadian cases of the virus occurred in Quebec and Ontario in 2002. Since its migration to Canada, annual West Nile infection rates straddle a high of 2,215 in 2007 and a low of five in 2010. Last year, there were 367 confirmed cases. While West Nile has visited every province save Newfoundland and Labrador, the hardest-hit areas, accounting for roughly 90 per cent of infections, remain the Great Lakes regions of Ontario and the shores of the Saint Lawrence River in Quebec.
West Nile, however, is not flying solo. Other mosquito-borne diseases are also making the rounds.
The Jamestown Canyon and Snowshoe hare viruses, weaker cousins of West Nile, have appeared across Canada, and Eastern equine encephalitis made its first domestic human appearance in Ontario in 2016.
Over the past 20 years, the incidence of mosquito-borne disease in Canada has increased 10 per cent. If warming trends continue, public-health officials and researchers at the National Collaborating Centre for Infectious Diseases warn that local pockets, including Southern Ontario, home to more than 12 million people, may develop ecosystems "that are conducive to the survival of exotic mosquitoes and the transmission of exotic MBDs" and the emergence and establishment of invasive, and comparatively lethal, "new strains of mosquitoes and new mosquitoborne diseases." The rest of Canada is not immune, as "climate change will increase the risk of endemic mosquito-borne diseases" across the country.
For the town of Komarno, its self-proclaimed reign as the enigmatically touristy "Mosquito Capital of the World" may be coming to an end. With climate change pushing the northern limit and boundaries for mosquito populations and mosquitoborne disease, new Canadian challengers may emerge to contest that title. Whether these towns and cities construct a towering monument to the mosquito is quite another matter altogether.
There are few animals in the Arctic for mosquitoes to eat, entomologist Lauren Culler says, 'so when they finally find one, they are ferocious.'
A British doctor in India holds the enlarged spleen of a young child afflicted with malaria in the 1920s. Malaria is one of the most prominent and deadly diseases that female mosquitoes carry.
LIBRARY OF CONGRESS
Manitoba town Komarno, which means 'mosquito infested' in Ukrainian, erected a giant statue of a mosquito in 1984 to pay tribute to the region's signature insect.
La Mal'aria, a painting from the late 1840s by Antoine Auguste Ernest Hébert, shows an Italian peasant family escaping by boat from a malaria epidemic.
A Soviet poster from 1942 shows a listless, glassy-eyed malaria patient and a chart of the disease's characteristic fluctuating fever.
NATIONAL LIBRARY OF MEDICINE
Anti-malaria messages featured prominently in U.S. propaganda during the Second World War, when the disease was a deadly risk for Allied troops in the Pacific campaigns.
NATIONAL LIBRARY OF MEDICINE