@lostcoastlorax.bsky.social:
the next time you see a possum, thank him/her (instead of trying to kill it) – they eat ticks. ‘Nuff said. #lymedisease #ticks #pestcontrol #opossum
@tinyfrightening.bsky.social:
We have way more ticks than usual, and I haven’t seen any opossums since mid-winter.
@race2extinct.bsky.social:
Invasive ticks are spreading, bringing new disease risks. Climate change plays a role—but so does 150 years of catastrophic bird loss and broader biodiversity collapse. Fewer predators = more ticks. Nature’s balance sheet is in the red.
Domestic cats are taking a toll on the birds….
Invasive ticks have scientists spooked about new diseases, Over 100 new tick species have entered the U.S. in the last 50 years. Scientists say it’s just the beginning by Olivia Ferrari, August 13, 2025, National Geographic
Between 2019 and 2023, seven ticks not native to the United States entered Connecticut, according to a new study published in the journal iScience. They came from a variety of countries as far away as Germany, Guatemala, Tanzania, Brazil, Scotland, and Poland.
While the study didn’t find evidence of these invasive ticks bringing new diseases to the U.S., experts say they could one day soon. Meanwhile, the study does suggest they could drive a rise in tick-related diseases already seen in the U.S., as they found these ticks can carry pathogens similar to those carried by native ticks.
Two invasive tick species from Central America tested positive for a bacteria similar to Rocky Mountain spotted fever, a disease that can cause fever, vomiting, muscle pain, and even death if untreated.
It’s part of an alarming trend: cases of tick-borne disease in the U.S. jumped from about 23,000 in 2004 to around 71,000 cases in 2022.
“Prior to 2018, here in the northeastern U.S… we didn’t have cases of Rocky Mountain spotted fever. But since 2018, we are seeing a number of up to ten cases of Rocky Mountain spotted fever in [Connecticut]. And we have had mortalities as a result,” says Yale University epidemiologist Goudarz Molaei, co-author of the new study.
Experts say identifying all the ways ticks can spread and carry diseases is critical to reducing the number of people who become seriously ill after being bitten. Their spread is a concern—during the last 50 years, over 140 non-native tick species have been brought into the U.S., hitching a ride on livestock, exotic pets, or people.
At the same time, climate change has expanded the habitat ticks can live in.
If more invasive ticks establish U.S. populations, “it is just a matter of time that these invasive ticks will either pick up local pathogens or native pathogens that circulate in the U.S., or they start carrying the pathogens that they transmit in their native range,” says Molaei.
How ticks spread diseases
Ticks pick up diseases after biting animal hosts like deer. They can then transmit disease to humans by biting us.
The U.S. is home to around 50 native tick species that bite people. Those bites can result in illnesses such as Lyme disease, anaplasmosis, babesiosis, and Rocky Mountain spotted fever.
(Learn more about how a warming climate is helping ticks reach new places.)
A crowdsourced and laboratory-validated tick map shows some species moving northward in recent years.
“We are seeing the increasing prevalence of pathogens in new counties, in new areas, that we never saw in 2019,” says Saravanan Thangamani, SUNY Upstate Medical University microbiologist whose research team created the tick map.
Molaei hypothesizes that not all these reported cases are “true” Rocky Mountain spotted fever, but instead a similar illness caused by the closely related bacterium R. amblyommatis—the same species the invasive ticks in the study are carrying.
“We have evidence that this bacterium is being carried by not only these invasive ticks coming from South and Central America, [but] some local ticks,” says Molaei.
The most successful invasive tick to enter the U.S. is the Asian longhorned tick, a relatively recent arrival that was first documented feeding on a sheep in New Jersey in 2017.Native to East Asia and now found in Australia, New Zealand, and the Pacific Islands, this tick has since spread to at least 21 U.S. states and Washington D.C. and carries pathogens responsible for various diseases that native U.S. ticks carry.
But a tick testing positive for a pathogen doesn’t necessarily mean it’s capable of transmitting that pathogen to humans, says Molaei.
“Investigations are ongoing to find out exactly to what extent [the Asian longhorned tick] bites humans, and what disease agents this tick will transmit,” says Molaei.
“Some of the early fears [about longhorned ticks] have not seemed to come to be realized,” Bryon Backenson, director of the Bureau of Communicable Disease Control at the New York State Department of Health. He adds that disease spread depends on ticks finding the right host and conditions: “Finding a pathogen in the tick is different from whether or not the tick can actually transmit it.”
New diseases in animals, but not humans (yet)
“To my knowledge there has not been a human clinical case acquired in the U.S. from an introduced tick,” says Risa Pesapane, Ohio State University disease ecologist. However, the longhorned tick did bring a non-native parasite called Theileria orientalis that can cause bovine theileriosis in cattle, says Pesapane, now widespread and dangerous for livestock health. And invasive ticks that arrived in Florida through the reptile pet trade now feed on native reptiles, adds Pesapane.
And climate change is predicted to create a hospitable environment for some warm-weather ticks that may not have been able to survive in a U.S. climate before, allowing tick populations to move farther north.
“One degree is a lot for [ticks]. One degree allows them to move way further north than they would otherwise,” says Backenson.
Climate change also means shorter winters, so both ticks and humans are active for more of the year. “We are seeing longer seasons where more ticks are active… and this generally means there are more days of the year where people are out wearing shorts and sandals and potentially encountering ticks,” says Pesapane.
One dangerous virus Thangamani points to is tick-borne encephalitis, which ticks carry in Europe and Asia and can be fatal. Although very few cases have been reported in travelers returning to the U.S., Thangamani claims if those ticks and pathogens were to establish themselves in the U.S., it would be a major threat to human health.
“Ticks are very resilient,” says Thangamani, adding that after feeding, a female tick can lay thousands of eggs. “All you need is one tick to establish a population in an area.”
Preventing tick-borne disease
While it’s unclear how risky invasive tick species are, it is something scientists are monitoring, says Hannah Tiffin, entomologist at the University of Kentucky.
“It’s something that we could do a better job with,” Tiffin says, suggesting better coordination among public health officials and scientists to identify ticks and pathogens before they spread.
Thangamani recommends using the tick map to see where you might be most at risk of getting a tick bite. His research team is also encouraging health care providers to refer to the map, so doctors can take it into account when treating patients with tick bites.
(Ticks are taking over city parks. Here’s how to avoid them.)
Travelers should let their doctors know of recent travel if receiving treatment for a tick bite, since some invasive and native ticks look similar, says Tiffin; without knowing a patient’s recent travel history, it’s easy to visually misidentify a tick species.
If hiking near home or abroad, wear protective clothes, use insect repellent, and stay away from tick-infested areas. Before returning to the U.S., Thangamani recommends travelers diligently check their bodies, clothes, and luggage.
He adds: “It is very easy to introduce a new species without us knowing it’s happening.”
Tick-borne Rocky Mountain spotted fever spreading in Canada, Potentially deadly disease already found in Ontario and Quebec this year by Emily Chung, CBC News, Aug 20, 2025
Quebec has reported its first case of the potentially deadly tick-borne disease Rocky Mountain spotted fever. The disease has also been reported in dogs in Ontario.
Here’s what you need to know about preventing, identifying and treating the disease.
What is Rocky Mountain spotted fever?
Rocky Mountain spotted fever is a disease caused by the bacteria Rickettsia ricketssiae. Symptoms in humans can include fever, headache, nausea or vomiting, stomach pain, muscle pain and lack of appetite.
The disease is named for the red rash that develops two to four days after the fever begins. The rash can range from pinpoint dots to red splotches.
The disease can be treated with the common antibiotic doxycycline, and most people make a full recovery.
But it can be deadly in five to 10 per cent of cases in the U.S. even with treatment, reports the U.S.-based Cleveland Clinic. Without treatment, one in four people die of the disease.
Dogs can also get Rocky Mountain spotted fever.
Dr. Scott Weese, director of the Centre for Public Health and Zoonese at the University of Guelph, said symptoms in dogs include fever, malaise, enlarged lymph nodes, loss of appetite and muscle aches that make the animals reluctant to move. The rash can sometimes be seen inside the dog’s mouth.
As with humans, the disease can be deadly in dogs, and Weese said one of the first dogs identified with the disease in Ontario died of it.
How is it transmitted?
It can’t be transmitted from person to person. It’s only acquired from tick bites — typically the American dog tick (Demacentor variabilis), which is found from eastern Alberta to Nova Scotia, especially in the southern parts of those provinces.
Weese says despite its name, it doesn’t target dogs specifically, but a variety of large mammals, including humans.
Previously, people didn’t worry about American dog ticks because they didn’t carry Lyme disease, which people get from the blacklegged or deer tick.
“Now we’re having to change our tune a little bit, realizing that this tick might not be as benign as we thought around here,” Weese said.
Like black-legged ticks, American dog ticks are found in grassy and wooded areas.
Ticks can also hitch-hike between dogs or from dogs to humans — something Weese thinks happened to him the other day with his own dog at home.
Other ticks that can carry Rocky Mountain spotted fever include the Rocky Mountain wood tick (Dermacentor andersoni) and the brown dog tick (Rhicephalus sanguineus).
Where is the disease found?
The U.S. sees 6,000 cases per year, especially in North Carolina, Tennessee, Missouri, Arkansas and Oklahoma, the Cleveland Clinic reports.
In Canada, the disease was known but rare in B.C., with an incidence of one case per 500,000 people in 2019.
There have been occasional cases of Rocky Mountain spotted fever reported in other parts of the country. A 73-year-old woman was diagnosed with the disease in 2023 after travelling from Saskatchewan to Ontario, and being in contact with her son’s two dogs in Ottawa.
The Ottawa doctors who saw the case said the disease’s expansion north into areas where it hadn’t been seen before was likely linked to milder winters and hotter, drier summers linked to climate change, which allow ticks to expand their range.
Earlier this year, a cluster of cases in dogs was linked to Long Point Provincial Park on Lake Erie in Ontario. Weese said such a large group in a small area was a surprise. “That would suggest that this is quite well-established, at least in some areas.”
This week, Dr. Alex Carignan, a microbiologist and infectious disease specialist with the regional health authority in Estrie, Que., reported a “recent” case in the province’s Eastern Townships.
Weese noted the Quebec case also seems to have been locally acquired, raising questions about how far the disease has spread in Canada.
Dr. Isaac Bogoch, an infectious disease specialist based at Toronto General Hospital, said the Ontario dog infections and the detection of Rickettsia bacteria in ticks north of the border had shown that the disease was already in Canada. “The real question is how much of it is here and what’s the geographic distribution.”
He added that other tick-borne diseases such as Lyme disease, anaplasmosis and babesiosis have spread more widely over recent years as shorter, warmer winters allow tick populations to push north.
What should people do to protect themselves and their pets?
Both Bogoch and Weese recommend people take precautions to avoid being bitten by ticks.
This can include staying on trails and away from places such as long grass and leaf litter; wearing long sleeves, long pants and insect repellent when possible while in areas where ticks might be; checking for ticks on themselves and their dogs after visiting such areas; and removing ticks promptly if found.
Weese said people with dogs are at higher risk because they’re more likely to walk in areas with higher risk of tick exposure and because dogs can sometimes bring ticks into homes in their fur.
Giving dogs oral or topical tick preventive medications can greatly reduce the risk of exposure, Weese said. However, it doesn’t replace other measures, and may not be as effective with Rocky Mountain spotted fever as it is with Lyme disease, since the former is transmitted more quickly.
Bogoch said health-care workers should be aware there are tick-transmitted diseases beyond Lyme that they should look out for, so that suspected cases of Rocky Mountain spotted fever can be treated immediately.
Weese recommended that if people or their pets fall ill after visiting wooded or grassy areas that might have ticks or Rocky Mountain spotted fever, they should mention the possible exposure to their doctor or vet to ensure prompt diagnosis and treatment.
He also noted that while people should be aware of these diseases, they’re still rare in Canada.
“Canada hasn’t been the hot spot for any of these ticks or their diseases in the past, and they won’t be the hot spot compared to the U.S. But we’re a hotter spot than we were.”