Maps from NASA satellite data
Chilling images of the
growing threat of ticks in North America are obtained from NASA satellite data.
The images accompany
recent research showing that warmer climates over the past two decades have
allowed deer ticks.
This ticks type carrying Lyme
disease to survive and invasion further into Canada and parts of the northern
United States.
The map shows how the risk
of encountering Lyme-bearing ticks has changed in parts of the United States
between 2000 and 2015.
Risk increase of tick-borne diseases
Ticks transmit a wide
range of bacterial, viral, and protozoan pathogens in many tropical and
temperate regions of the world.
Blacklegged ticks that
transmit Borrelia burgdorferi, are of particular concern in North America.
This bacterium causes Lyme
disease in the southern-eastern and central Canada.
It is now widely
recognized that the rise in temperature associated with the global climate
change has contributed to an overall increase Ticks.
This increase, include the
number, types, activity levels, and geographical distribution of ticks in North
America.
Also, it has directly
favored the invasion of blacklegged ticks and Lyme disease northwards into Canada.
Model to map invasion of several tick kinds
A set of researchers led
by Serge Olivier Kotchi of the Public Health Agency of Canada published their
study in the journal Remote Sensing.
They created a model to
map the invasion of Ixodes scapulae, the black-legged deer tick, and main vector
of Lyme disease.
The studies are
established across central and eastern Canada between the years 2000 and 2015.
This modeling was based
on meteorological data collected by NASA and other satellites.
It measures the surface
temperature of the region and the frequency with which it was covered by woody
vegetation throughout the year.
It was then adjusted using previous field research that has tracked tick populations in Canada over time.
Warmer periods allowed ticks survival
- Ticks survival in Canada
As other research has
shown, warmer days (days above 32 degrees Fahrenheit) have become more frequent
in Canada over time.
And these warmer periods
have allowed ticks that might have died in the coldest parts of the year to
survive into the next season.
As a result, the
environmental risk of encountering these ticks has continued to increase in
these areas, particularly in Ontario and Quebec.
"Ixodes scapulae
continue to expand geographically in south-central and southeastern Canada.
This is accompanied by
continued increases [in the] incidence of human cases of Lyme disease,"
the authors wrote.
"Climate change, with
increasing temperatures, is thought to facilitate this range expansion."
This recent study suggests
that the risk of contracting Lyme disease has steadily increased over the years
in central and eastern Canada.
The red areas represent
the highest risk.
While the main findings of
the study concern Lyme risk in Canada, the same trends are occurring nearby in
the United States.
- Ticks survival in United States
The following information
is reported from a paper published today by NASA Earth Observatory on Kotchi's
study.
The study illustrates how tick
risk has changed in the central and northeastern United States over the same
years.
Other data showed that
Lyme disease and other tick diseases have been on the rise in the United States
in general.
The data is from the
Center for Disease Control and Prevention.
While Lyme was first
discovered and is still most commonly diagnosed in the north-eastern United
States, cases are starting to become more common elsewhere.
Earlier this year, a study
found that the bacteria that cause Lyme disease even thrive in vegetation near
the beaches of northern California.
