Ticks coming

As the temperature rises around the world, ticks begin to feel at ease in more and more regions of the planet, and Lyme disease is becoming the first epidemic caused by climate change.

Evolution has endowed the American white hare with a particularly skillful skill. For a period of about 10 weeks, when days fall in the hills and arctic forests, an agile night hare is transformed. From reddish-brown, suitable in color to the needles of pines and branches of trees, among which it produces food, it turns into silvery-white - just at the time of the fall of winter snow. And this transformation is not in vain. Lepus americanus, as he is known to science, is able to jump three meters and run at speeds of up to 43 km / h, thanks to his powerful hind legs and a fierce desire to survive. But still, according to one study, 86% of hares end their lives in the form of a lynx lunch, a fox, a coyote, or even a goshawk or a Virginian owl. Changing clothes - a way to remain invisible, to hide in the bushes or run across the snow unnoticed in order to extend their lives for at least a period sufficient to leave offspring.

White hares are widespread in the cold and high-mountainous places of North America - in the wild regions of western Montana, on the coniferous slopes of Alaska and in the inaccessible places of the Canadian Yukon. The Yukon is part of Beringia , a vast ancient territory that united Siberia and North America with an isthmus that, after the end of the last ice age 11,000 years ago, gave way to the Bering Strait. For thousands of years, many mammals, plants and insects have moved along this isthmus to the west and east, creating a rich arctic forest. But this permanent cold terrain to the north of the 60th parallel, with early snow and solid ribbons of ice, has changed, by geological measures, in an instant. Over the past half century, the average temperature has risen there by 2 °, while in winter there is warmer by 4 °. Glaciers are rapidly retreating, releasing streams of ancient water into Lake Clauin , a 400 km ² water basin, which is called the pearl of the Yukon. Thunderstorms, ice jams, forest fires and rains suddenly began to occur there much more often. Permafrost disappears.

Such rapid changes in vast areas of the northern territories test the adaptive abilities of the hare, no matter how agile and nimble it may be. Snow falls later, it melts earlier, but changes in the skin of the hare occur according to the long-established schedule - and sometimes the hare turns out to be snow-white, while its environment is still brown. Because of this, it becomes easier prey for predators. In 2016, wildlife biologists who tracked hares in the wilderness of Montana called this phenomenon “camouflage mismatch caused by climate change.” Hares molt, as always. Just the snow does not fall. And their survival rate fell by 7%.

To outwit his new enemy - warm winters, hares will need something like a miracle, which biologists have written an article for the journal Ecology Letters, called "evolutionary salvation." As in the Yukon, it is assumed that there will be less and less snow in the explored corner of Montana; It is possible that by the middle of the century the forest will remain uncovered with snow for another whole extra month, and without snow hares will stand out against the forest no worse than white inflatable balls.

In the list of animals that will have to adapt or die, it is necessary to record and moose. The awkward king of the reindeer family, known for his horns that look like giant open fingers, can reach two meters wide, faces a whole list of threats to livelihood, from wolves and bears to cysticercosis and liver flukes . But in the late 1990s, in many of the northern states of the United States and in Canada, a new attack began to mow elks, elks and elks.

Lee Kantar is a moose biologist who is based in Maine, which means he makes a living climbing through hard-to-reach places in the north and center of the state when a GPS collar reports the death of another moose. A skinny man with a striking gray mustache, wearing a flannel shirt and jeans, Kantar provided 60 elk collars in January 2014 near Lake Mushhead [Moosehead Lake - moose head / approx. trans.] in the mountainous terrain in the west of central Maine. By the end of that year, 12 adult moose and 22 calf died - 57% of the entire group. When biologists studied their remains, they discovered the cause of death. On the carcasses of the calves that were not even a year old, there were up to 60,000 bloodsucking arthropods, known as the winter tick . In Vermont, up to 100,000 ticks could be found on every dead moose. In New Hampshire, the elk population fell from 7,500 to 4,500 between 1990 and 2014, and the same abundant tick populations could be found on the emaciated animals. From these magnificent animals literally drank all the blood.


Elk "ghost" with a significant loss of coat in New Hampshire

Winter ticks attack moose since the end of the XIX century. In a typical year, an elk can carry from 1,000 to 20,000 ticks. Particularly fierce in winter, when moose are malnourished and weakened, anemia and hypothermia, enhanced by the influence of ticks, can tip the scales in favor of death. Bill Samuel, a retired biology professor at Alberta University, spent his entire career studying North American moose. Once he carefully counted the number of ticks on a moose found in Alberta in 1988 — 149,916. In a 2004 book, he recalls how ticks killed moose in Saskatchewan in the spring of 1916, in Nova Scotia and New Brunswick in the 1930s, in the National Park Elk Island in central Alberta from 1940 to 1990. Some of the animals were so severely affected by ticks that there was not a single free space on their favorite places of arthropods - on the anus, in the groin, on the sternum, withers and shoulders. In useless attempts to get rid of parasites, poor animals rubbed against the trees, which led to the loss of fur and left gray spots on the skin. Such animals are called "ghost moose."

Elks have long died from diseases, predators, hunting, and sometimes from ticks. But their losses in the 21st century have other, more threatening, more powerful consequences. In 2015, two environmental organizations wrote a petition to the US Secretary of the Interior asking that the moose of the Midwest be endangered. In Minnesota, the number of moose in the previous decade fell by 58%, approximately the same decrease is observed in New England. Environmentalists believe that by 2020 in the Midwest moose may disappear altogether.

Kantar knew that ticks kill his moose in Maine. It became clear why the winter mites struck his flock, and drank almost half of the blood, clinging to any available piece of skin. “The greatest threat to this species,” declared the non-profit center for biodiversity and respect for the Earth in its 2015 petition, “is climate change.”

Not hunters, not loss of habitats, or even environmental pollution - although this is also important. Elks love the cold and need it. They become lethargic in heat, cannot eat normally, become weak and vulnerable. During warmer and shorter winters in the Midwest and Northeastern United States, huge amounts of winter ticks survive waking up when trees come to life all earlier in the spring, and they have more time to climb tall bushes, stretch their paws and wait for an unsuspecting and unprepared elk. When moose lie in the snow, they leave blood stains from swollen ticks. When a calf is born in Minnesota, a mob of hungry ticks moves from mother to newborn. Elks shed these fat ticks in large quantities on the ground in autumn and winter, and ticks, instead of freezing in the snow, hiding in the leaves - because of this, the death rate of ticks falls, while in elks it grows.

Samuel is a careful scientist, not inclined to make hasty conclusions, and he notices how many factors work together to destroy elks in a complex ecosystem of wildlife. Wolves, liver flukes, cysticercosis, uncontrolled hunting, the loss of places to live - all this adds up to the big picture. Because of the influence and susceptibility to other factors, “Climate change,” he said to me, “may be the main one.”

Tick ​​problem

Gil Auerbach knew that winter ticks, stuck to the dead and dying moose, do not pose a threat to people whom they practically do not bite. But when she heard news of how moose lose half of their blood due to ticks, she was terrified. Auerbach, an active woman over the age of 70, about 30 years ago was bitten by a tick, common in forests and thickets in the region where she lives - in the Hudson Valley of New York State. Because of this tick, she lost 10 years of life, she had to resign from the position of a highly qualified programmer from a nearby IBM unit, and she still suffers from the effects of Lyme disease, which was discovered too late. “She put me on her knees,” says Auerbach, who belongs to a fairly large group of people who have contracted Lyme disease and are suffering from its long-term symptoms. From her point of view, the invasion of winter ticks is one of the indicators of the fact that the environment flew off the coils, as well as a smoother, but continuous increase in the number of black-footed ticks , one of which bit her 30 years ago.

This last tick is known to scientists as a member of the Ixodid family - in its case it was Ixodes scapularis, a black-legged tick. They are distributed in the United States and other countries with incredible promptness. Canada, Britain, Germany, Scandinavia, Inner Mongolia in China, Tula and Moscow regions in Russia: they all face a huge and ever-increasing number of disease-carrying ticks. Infected ticks are found in the parks of London, Chicago and Washington DC, and in the green expanses of Killarney National Park in southwestern Ireland. In Western Europe, there are no standards for reporting tick counts, and the official number is approximately 85,000 per year. An analysis from 2016, published in Oxford, the British journal of Public Health, indicates 232,000. Signs of a growing problem are seen in Japan, Turkey and South Korea, where the incidence of Lyme disease increased from zero in 2010 to 2000 in 2016. When I asked three Spanish doctors in 2017, where you can find Lyme disease in Spain, one said “everywhere” and the rest agreed with him. One of them, Abel Saldarreaga Marin, treated forest service workers in Andalusia, where, according to him, symptoms are usually treated with traditional methods. In the Netherlands, as elsewhere, warnings designed to protect local walkers, children and gardeners from being bitten did not cope with the growth of bites for years, and then, apparently, the number of cases reached a saturation point, and now Ixodes ricinus, or dog tick , lives there in 54% of the territory.

And on the other side of the Atlantic, the Centers for Disease Control and Prevention (CDC) of the United States in Atlanta updates maps every year that show black Lyme disease cases in US districts. For the first time such a card was officially released in 1996, although even then the disease was quite common. The points on this map form a non-vanishing black spot that stretches along the Atlantic coast, from Delaware to Cape Cod, New Jersey, Connecticut, Massachusetts and to the lower boundaries of New York State - where the disease caught Auerbach. Blurred shadow goes along the border between Wisconsin and Minnesota, in addition, many points are found in the middle states. But it is precisely the change of these cards over the course of 18 years that shows the rise of Lyme disease in the manner of notebooks with animation, in which pages should be turned over - it spreads throughout the Northeast and Midwest USA.

In 1996, Black-footed ticks settled - that is, their number was sufficient to maintain the population - in 396 US districts. By 2015, researchers found that they had settled in 842 districts - that is, 113% more. It is noteworthy that the changes on the tick distribution map from 1996 to 2015 practically coincide with the map of the spread of Lyme disease.

Auerbach, who became an environmental activist with deep knowledge about the problems of this disease, has been finishing her letters with the passage for years: “What is the problem? In ticks, of course! ”She believes that they should be stopped, and the map from 2015 shows why. It shows how ticks move to such places that only 10 years ago were considered unsuitable for their habitat - from the Allegheny Mountains to the Mississippi Valley, from western Pennsylvania to the south and east, through Kentucky and Tennessee. In Minnesota and Wisconsin I. scapularis “apparently expanded their range in all directions,” as researchers at the CDC wrote, and these words are remarkable and alarming. Ticks "spread inland from the Atlantic coast and went both north and south," they write, not spreading only to the east, where the Atlantic Ocean lies.

Lyme disease appeared on the coast of Connecticut in the 1970s, when symptoms similar to rheumatoid arthritis were seen in a group of children who had the misfortune of being pioneers in the disease, the key to the treatment of which would be early therapy. Late diagnoses can be marked by long and complex symptoms - fatigue, joint pain, learning problems, absent-mindedness and depression. Parents and counselors for the treatment of children who have had the disease, as well as the children themselves, who grew up to 20 years of age, told me about the lost school years. The most per capita cases of infection were found in children 5 to 9 years old, and most often people aged 60 to 64 years go to hospital, according to a study of 150 million records in US insurance, made from 2005 to 2010.

The history of the emergence of Lyme disease in our time, its distribution in dozens of countries around the world and the millions of cases need to be told in the perspective of the modern community living in a modified habitat. Over the last quarter of the 20th century, a delicate set of natural forces was broken, and turned Lyme disease from an organism that had quietly lived for thousands of years into what we have today: a set of horrible stories that mothers share; difficulties for doctors who lack good tests and clear lines of research; an object of hate for research that rejects the persistence of infection but confirms the presence of unpleasant effects.

CDC does not use the word "epidemic" to describe Lyme disease. He prefers " endemia ", that is, "the constant presence and / or widespread prevalence of the disease or the carrier of the disease among the population in a particular area." But Lyme disease, after all, had not previously been widespread, and in general it was not there before. Also, it is not limited by any borders. The linguistic choice of the CDC is unsuccessful. It minimizes the importance of the disease, which each year affects from 300,000 to 400,000 people in the United States, is found in at least 30 countries, and perhaps in a much larger number of them, and is rampant throughout the world. Lyme disease is moving, breaking out, spreading like an epidemic.

Lyme disease mites are not spider insects, but spider-like. They cannot fly and jump, but we can say that they climb mountains, cross rivers, travel hundreds and thousands of kilometers to new habitats. All this is documented by scientists looking for ingenious ways to track and count ticks. They pull white flannel cloth over the scattered foliage of the scaffolding, sometimes blowing carbon dioxide into them, which causes the mites to stretch their forelimbs in an attempt to grab lunch. They catch migratory birds infected with arachnoid hitchhikers. They count the number of ticks on the ears of caught mice and shrews, in the process of which they sometimes undergo bites. They dissect the nests of birds, open the carpet of fallen leaves, sift overgrown sand dunes with grass.

When researchers are lucky, they find data from other eras confirming their sense of the onset of change. In 1956, the Bosnian scientist Tsvetanovich from Yugoslavia reported that I. Ricinus is not able to survive at an altitude of more than 800 m above sea level. But when Jasmin Omeragich from Sarajevo University took a new dimension in 2004, collecting 7085 dog ticks in the Dinar Highlands in Bosnia and Herzegovina, he found that ticks feel comfortably at altitudes up to 1190 m. In 1957 in Šumava, which was then in Czechoslovakia, researchers concluded that ticks are unable to dwell at altitudes of more than 700 m above sea level. By 2001, biologists had found them already at altitudes of 1100 m. These early observations, which, according to Jolyon Medlock, a medical entomologist from the British Ministry of Health, and his colleagues, "are clear evidence of the high altitude spread of I. ricinus". That is, ticks aggressively move up.But they are moving in other directions - and in those places that are better adapted for humans than the steep slopes of the mountains.

In the Hudson Valley, a team from the University of Pennsylvania used the Ixodes DNA to build a family tree of black-footed ticks - much like people used saliva swabs to search for distant relatives in the genetic code. Investigating ticks collected in four places from 2004 to 2009, the researchers reconstructed the pattern of their migration up the river for 200 km. The tree begins its history in the south of Yorktown, where tests show that ticks have lived for the last 57 years. Then, after 17 years, these octopus pioneers climbed to the next step, reaching the Pleasant Veli. After another 11 years, they settled in Greenville, at the foot of the Catskill mountain range., and after 17 years, appeared in the north of Gilderland, where in 1639 migrants from the Netherlands appeared. And although other strains were constantly intertwined in the DNA, the one that came from the south of Yorktown always remained dominant. DNA data, as the researchers write, "unequivocally support the theory of the spread from south to north." Against all odds, ticks move to places where it has always been colder and more snow. And feel great.

In Europe, ticks are also marching northward tirelessly. In Sweden, researchers studied the development of a dog tick population from 1994 to 1996, dragging tissue at 57 sites and interviewing locals for bites and tick detections. They set the penetration limit at a latitude of about 60 ° 5′N, above which ticks did not survive. By 2008, ticks had already been found 500 km to the north, along the Baltic coast, to about 66 ° N north. The same thing happened in Norway.

Periodic observations from 1943 to 1983 showed that ticks do not survive north of 66 ° N s. By 2011, they had already passed 400 km, to the northernmost latitude in Europe, up to 69 ° N. This record, which, apparently, is destined to fall, reported researchers from Oslo. Nicholas Ogden, a senior researcher at the Canadian Ministry of Health's National Microbiology Laboratory, watched the last two decades as black-footed ticks crossed the US border on their way up and dived 1000 km into Canada. In 1990, the only documented site for tick detection in Canada was located in southern Ontario in the city of Long Point, located on the land portion of Lake Erie, and located much closer to New York than Ottawa, Toronto or Montreal.In less than 20 years, ticks have settled in dozens of new locations in Canada, including Manitoba, New Brunswick and Nova-Scotia.

In 2008, Ogden and his colleagues identified the risks of moving ticks to the north and predicted “possible widespread distribution” to the south of central Canada. In 2015, another study expanded this prediction: ticks that carry Lyme disease by 2050 will move towards the pole by 250-500 km. Canada is in the same place where the United States was in the 1980s, and Ogden is aware of this. The second largest country in the world, which observed a 12-fold increase in cases of Lyme disease from 2009 to 2013, faces a full-scale epidemic. “This is becoming a real public health problem,” he told me.

In 2015, Ogden and his colleagues used a new way to track the movement of ticks through the migration of birds. A small short-tailed thrush appears on the scene.- dim, medium-sized bird, very secretive, which hides in the underbrush, because of which it often collects ticks on itself. Ogden’s team caught 72 such birds crossing the Canadian border on their way to the north. The researchers then studied the molecular structure of their fragile feathers from a metallic-gray tail. These tail feathers, helping the bird to change the direction of flight, carry a certain imprint, hydrogen isotopes from the water of the region where the bird fled. Knowing that birds usually return to where they grew up, scientists concluded that birds can help explore large areas stretching from northern Ontario to southern Arctic Canada. Charles Francis, tracking bird populations for the Canadian Wildlife Service, helped in this study.

“It is very likely that ticks constantly fell into the northern territories due to bird migration,” he said. It's just that today more ticks carried by them survive in more places. By 2017, Canadian researchers reported that rather large areas of Ontario had turned, as written in the work for the magazine Remote Sensing, from "unsuitable to habitable" ticks that carry Lyme disease. While white hares are struggling to survive in Montana, ticks and their pathogens thrive in the warming world, colonize more and more places and breed there, just as they did during the warming period after the last ice age. 30 years ago, physicians in Canada told sick people that they almost certainly picked up the disease somewhere else, most likely while traveling in the United States.By the first decade of the XXI century, this confidence is no longer there.

In 2014, the United States Environmental Protection Agency (EPA) released a 112-page report on the future of the United States in the warming world. It begins with a conclusion that was rejected, politicized and ignored in the United States for decades, and finally, at least for a while, they decided to accept:

The climate of the Earth is changing. Temperatures are rising, patterns of snow and rain are changing, and more and more extreme climate events are occurring - heavy rains and record high temperatures. Scientists are quite confident that many of these events can be associated with rising levels of carbon dioxide and other greenhouse gases in our atmosphere caused by human activity.

The report consists of six sections that attempt to describe and quantify the impact of global climate change on the oceans, on glaciers, on forests, lakes, and on people. In the third edition of the 2014 report, the agency included four new indicators to help monitor and measure the impact of climate change. Among them - the amount of energy used for cooling and heating (from which it is clear that cooling takes more energy), the number of forest fires, water levels and temperatures in the Great Lakes, and the spread of Lyme disease.

From now on, the EPA will track the number of cases of Lyme disease detected in the United States as the official description of climate change. This tick-borne disease, the victims of which have been 4 million people in the United States since the 1990s, was the only disease that had this dubious honor. The agency, arguing about the effects of warming on health, mentions two other trends that need to be monitored: heat-related deaths, estimated to be 80,000 over the past thirty years, and ambrosia in bloom seasons, which cause allergies in millions of people. But Lyme disease has an important difference. It is spread by ticks, whose “population is influenced by many factors, including climate,” as the EPA writes in a report.

In the states from Maine to Florida, from New York to California, throughout southern Canada and in many parts of Europe, the once-vast expanses are diminishing, dividing, turning into idealized forest parks on the periphery of roads - into places where people can be in nature and support her. Many live, work and play alongside these green spaces in the new era, called the anthropocene, in an era marked by human influence. The irony is that these modified pieces of nature are incubators of Lyme disease. The smaller the piece, the greater the proportion of infected ticks on it, as noted in one of the studies conducted in Datches county of New York, where the number of cases of Lyme disease per capita is on the top lines in the world ranking.

In these natural areas, small mammals, for example,North American white-footed mice and European garden sony find refuge, flourishing in the absence of predators such as foxes. In the language of tick-borne diseases, mice become masters of ticks and reservoirs for Lyme disease, a place where newborn ticks, so small that it is difficult to see with the eye, receive their first bite of infection. In urban parks, suburban roads and forest parks, people come into contact with these ticks. In many studies, factors that fuel the epidemic are other aspects besides climate change, many of which also depend on people. Cutting forests into small areas and loss of biodiversity are clearly in the first places of this list.

But while not finding one explanation for the appearance of Lyme disease in the twentieth century, there is plenty of evidence that climate change played a significant role in this. On the Pinkam-Notch Pass in the northern foothills of the Appalachian Mountains in New Hampshire, snow depth decreases every year by an average of 1 cm since 1970, and the number of days with temperatures below zero falls by three days in ten years from 1960. In New Hampshire, lilacs are blooming earlier - and in this state there are still large territories, untouched by people, whose population is just over 1 million, and the plant growing seasons have lasted for 2-3 weeks. New Hampshire ranks second in the number of cases of Lyme disease in the United States in 2013, immediately after neighboring Vermont.

In the Krkonoše Mountains in the north of the Czech Republic, the temperature has increased by 1.4 ° over four decades, and I. ricinus survive at an altitude of up to 1,300 m above sea level. “It's not that they decide to go climbing,” Michael Kotsifakis from the University of South Bohemia told me. “They just can survive in these areas.” In the area of ​​Montereji in southern Quebec, extending south from Montreal to the St. Lawrence River, the temperature has increased by 0.8 ° since the 1970s, and white-footed mice thrive during a shortened and warmer winter. “The habitat is moving rapidly toward the pole,” wrote Canadian researchers in 2013, pointing to “increasing evidence supporting the hypothesis that warming up climate is a key cause of Lyme disease, which works on many levels of the disease transmission cycle.”

The following questions arise: Has the epidemic caused climate change? Or does the change simply feed this disease, moving ticks and animals, their owners, to new places and to new people? Testimonies speak of the latter. The first is more difficult to confirm. But Lyme disease was the first disease that emerged in North America, Europe and China in an era of climate change, the first one to be ingrained, widely spread and affecting different groups of people. It grows in places like Australia, where residents are also told that they have some other disease, or that they have picked up the infection somewhere else. “We are on the island, and we think in terms of the island,” said Trevor Cheney, general practitioner from the north coast of New South Wales, who regularly diagnoses Lyme disease, although doctors say that it does not exist in Australia."As if migratory birds scattering ticks, they do not fly here," he told me at a conference in Paris.

Incorrect diagnoses cost many Lyme disease patients the precious time needed to seek treatment. Medical experts make the mistake of believing that in the future everything will be as it was in the past. Lyme disease is moving to new places, as it has done for the last 50 years. In the decades since the infection of children in the city of Lyme in Connecticut, very little progress has been made in areas such as controlling the spread of ticks, protecting people from bites, accurate testing for the Lyme pathogen, Borrelia burgdorferi, and especially adequate treatment of victims. Ixodes mites - black-legged, doggy, or any others - deserve our respect. They are armed not only with Lyme disease, but also with a growing array of germs; bacteria, viruses and parasites, known and still undiscovered.Sometimes mites are able to infect with one bite at once with three or four diseases. They are so agile that two mites feeding side by side on the same animal can transmit pathogens to each other without infecting the host. Lyme pathogen is so cunning that ticks infected with it find a victim more effectively than non-infected ones. These ticks cannot fly, jump or track the victim for more than a couple of steps of a person. But they changed many lives, cost billions of dollars in medical expenses and brought fear into walks through the woods or children’s games in the grass — into our relationship with nature.than uninfected. These ticks cannot fly, jump or track the victim for more than a couple of steps of a person. But they changed many lives, cost billions of dollars in medical expenses and brought fear into walks through the woods or children’s games in the grass — into our relationship with nature.than uninfected. These ticks cannot fly, jump or track the victim for more than a couple of steps of a person. But they changed many lives, cost billions of dollars in medical expenses and brought fear into walks through the woods or children’s games in the grass — into our relationship with nature.

And all this is even more unpleasant when we realize that it was we who caused this.