Climate change: Disease-ridden pet dog ticks may jump to humans as temperatures soar | Science | News
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One of the scientists involved has warned people should be “concerned” about the study’s suggestion that hotter weather may lead to more tick-borne disease transmissions to humans. Researchers focussed on brown dog ticks, which can carry deadly Rocky Mountain spotted fever.
According to the US Centers for Disease Control and Prevention, reported cases of Rocky Mountain Spotted Fever and other diseases under the Spotted Fever Rickettsiosis category have increased from 495 in the year 2000 to a peak of 6,248 in 2017.
The CDC said symptoms include a fever, headache, and rash, and warns the bacterial disease can be deadly if it is not treated early with appropriate antibiotics.
Scientists recently found that brown dog ticks, which carry the disease, were over twice as likely to prefer humans over dogs as their hosts when they increased the temperature in a lab.
Brown dog ticks, pictured, can spread diseases to humans
Laura Backus, lead author behind the study, warned more frequent outbreaks of Rocky Mountain spotted fever can be expected as hot weather becomes more common.
She said the ticks can be found on all continents around the world except in Antarctica, and that dogs are usually their preferred hosts.
However, when she and her team placed a dog and a human at two ends of a tube in which the ticks were contained, they found the ticks tended to move towards the human as they increased the temperature from 23 degrees C to 38 degrees C.
A dog is led into a box to take part in the test. Researchers told Express.co.uk they were protected from the ticks by a mesh.
Dr Backus told Express.co.uk: “These results suggest that, at least for zoonotic diseases carried by brown dog ticks, we can expect to see more cases with increasing temperatures.
“Here in the US, we are primarily worried about Rocky Mountain spotted fever carried by brown dog ticks, and based on these results expect that with more hotter weather, we may see more human cases.
“We can’t extrapolate what we found to all tick species or all regions of the world, but the brown dog tick is widespread and if it begins to bite humans more frequently, we can expect more disease transmission to occur.”
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The boxes, one containing a dog and one containing a human, were joined by a tube with ticks inside
She added that, in the test, the ticks were prevented from actually reaching the dog or the human by a mesh, to prevent them from becoming infected.
The study was conducted at the Davis School of Veterinary Medicine at the University of California, and the findings were announced at the American Society of Tropical Medicine and Hygiene’s 2020 annual meeting.
As to whether Britons should be concerned by the findings, Dr Backus said: “I don’t recommend alarm.”
Dog tick removal
She said brown dog ticks are “not currently established in the UK”.
However, the ticks are found across southern regions of the US, and the study notes they could begin to spread further northwards away from the equator as average temperatures rise.
Dr Backus advised pet owners to “speak with their veterinarian about the best option for their pet in their region”.
Climate change may see more human cases of illness associated with the dog ticks
Last week, the World Meteorological Organisation said 2020 is on track to be one of the three hottest years ever recorded.
WMO Secretary-General Petteri Taalas said: “The average global temperature in 2020 is set to be about 1.2 °C above the pre-industrial (1850-1900) level. There is at least a one in five chance of it temporarily exceeding 1.5 °C by 2024.”
The UN says the 1.5C threshold is a milestone climate scientists are urging world leaders not to reach, as set out in the 2015 Paris Agreement.
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