Post by walkswithblackflies on Jun 16, 2021 6:55:49 GMT -8
Since NY straddles the Northeast/Mid-Atlantic, I posted in both forums:
By Glenn Coin | gcoin@syracuse.com
Syracuse, N.Y. – In May 2020, New York residents mailed 442 ticks to Upstate Medical University’s lab to test for diseases.
This May, the lab received 1,548 ticks – more than triple last year’s number.
“Ticks are exploding,” said Saravanan Thangamani, who runs the testing lab.
It gets worse: Not only are there more ticks this year, but a greater share of them carries microbes that make humans sick, especially the bacterium that causes Lyme disease.
In the first five months of 2020, 22.4% of the ticks tested by the lab carried at least disease-causing virus or bacterium, Thangamani said. In the first five months of this year, it was nearly 37%.
“The individual number of ticks is one concern,” Thangamani said, “but the bigger concern is that the prevalence of agents in these is pretty high.”
And a crash this year in the population of white-footed mice, the tick’s favorite source of blood, means an abundance of hungry ticks are seeking any warm-blooded animal they can find.
“Ticks are looking for other hosts, and some of those hosts might include us,” said Richard Ostfeld, a disease ecologist at the Cary Institute of Ecosystem Studies, in the Hudson Valley, the epicenter of Lyme in New York. “That’s the worst-case scenario for human risk.”
The state health department is also seeing more ticks than last year at most of its 100 sampling locations, a spokeswoman said.
Tick researchers saw this coming, said Ostfeld. A complex sequence of ecological boom-and-bust cycles, overlaid on the tick’s own two-year life cycle, created the perfect storm for human disease risk, he said.
It started in fall 2019, when oak trees produced a bumper crop of acorns across much of the eastern U.S. White-footed mice gorged themselves of that surfeit of high-energy food, and in spring 2020 produced a population explosion of their own. Ostfeld said in boom years like 2020, the mouse population can be 20 times higher than a normal year.
That “eruption” of mice, he said, meant it was easier for ticks to find what scientists call their blood meal. More larval ticks survived to to the nymph stage, which is responsible for more than three-quarters of Lyme disease cases in humans.
Nymphal ticks are the main transmitters of Lyme and other diseases for two reasons:
-- They are most active in the summer, when humans are tramping through forests and trails.
-- They’re tiny – about the size of a poppy seed – so they’re harder to see on the skin than the larger adults. The longer a tick attaches unseen to skin, the higher the chance it will pass on diseases.
When tick larvae hatch from eggs in the spring, they are free of disease. They ingest viruses and bacteria from infected mice and other small mammals, and can then pass on those microbes when they feed as nymphs and again as adults.
Another reason for the spike in ticks this year is a pair of consecutive warm winters and springs, Thangamani said. Fewer ticks are killed by the cold, and animals are more active.
“When weather warms up, humans get outside,” he said. “For small mammals like mice, they want to get out of their burrows and look for food. It’s a perfect opportunity for a tick to latch onto a mammal, whether it’s us or wildlife.”
The state health department said odd-numbered years tend to have more ticks than even-number years because of their two-year life cycle.
Add it all up, and 2021 is a particularly bad time to be a human being walking through the forest or grass, where ticks wait to latch onto passing prey.
“Because an abundance of mice in 2020 leads to this boom in nymph stage ticks in 2021 and a crash in the mice in 2021, those ticks are hungrier than usual,” Ostfeld said.
The nymphal ticks will keep feeding throughout the summer, as more people head outdoors and increase their chances of encountering a tick. A tick feeds only three times in its two-year life span: as a larva, a nymph, and finally as an adult. Adult ticks are most active in the fall, as females seek one last meal before winter. Adult ticks are most likely to carry disease because they’ve already fed twice on other animals that might be infected.
While researchers expect that this year’s tick boom will lead to more cases of Lyme and other diseases in humans, it’s too early to confirm that.
“We’re still early in the nymph season,” Ostfeld said. “We’re collecting data as we speak.”
Many cases of tick-borne disease are never reported or confirmed. Even when cases do get reported to state and federal health agencies, it can be months or years before the data is reviewed and released.
Meanwhile, envelopes with ticks inside continue to pour into the Upstate lab. On June 8, 201 ticks arrived in the mail, the highest single-day total since the lab launched the free testing program in April 2019, according to the lab’s Twitter account. The program’s purpose is two-fold: to tell residents if ticks they find are carrying diseases, and to use citizen science to map the distribution of ticks and those diseases.
Since the program began, the lab has processed more than 11,000 ticks. Of those, 80% are black-legged ticks, also known as deer ticks. That’s the species of greatest concern because it carries the Lyme bacterium.
A third of black-legged ticks tested at Upstate contain that bacterium, known as Borrelia burgdorferi. About 10% had bacteria that causes babesiosis, a disease with symptoms similar to Lyme: fever, body pain, headaches and fatigue.
Thangamani said the flood of ticks arriving at the lab isn’t just because more people are hearing about the testing program.
“I talk to some of my peers who are noticing an increase in ticks, up to 50% of deer ticks,” he said. “I did a phone call with some colleagues in Connecticut and Massachusetts, and they see an increase.”
If there’s any silver lining to this year’s tick season, it’s that the risk of getting a tick bite will likely drop in 2022. Fewer ticks are expected to survive this year because of the fall in the mouse population, Ostfeld said.
But ticks and the diseases they carry – up to seven different pathogens have been identified in ticks in New York – are here to stay.
“When ticks are established, they’re going to keep expanding,” said Brian Leydet, an epidemiologist and tick expert at SUNY College of Environmental Science and Forestry. “It’s always going to be worse and worse and worse.”
By Glenn Coin | gcoin@syracuse.com
Syracuse, N.Y. – In May 2020, New York residents mailed 442 ticks to Upstate Medical University’s lab to test for diseases.
This May, the lab received 1,548 ticks – more than triple last year’s number.
“Ticks are exploding,” said Saravanan Thangamani, who runs the testing lab.
It gets worse: Not only are there more ticks this year, but a greater share of them carries microbes that make humans sick, especially the bacterium that causes Lyme disease.
In the first five months of 2020, 22.4% of the ticks tested by the lab carried at least disease-causing virus or bacterium, Thangamani said. In the first five months of this year, it was nearly 37%.
“The individual number of ticks is one concern,” Thangamani said, “but the bigger concern is that the prevalence of agents in these is pretty high.”
And a crash this year in the population of white-footed mice, the tick’s favorite source of blood, means an abundance of hungry ticks are seeking any warm-blooded animal they can find.
“Ticks are looking for other hosts, and some of those hosts might include us,” said Richard Ostfeld, a disease ecologist at the Cary Institute of Ecosystem Studies, in the Hudson Valley, the epicenter of Lyme in New York. “That’s the worst-case scenario for human risk.”
The state health department is also seeing more ticks than last year at most of its 100 sampling locations, a spokeswoman said.
Tick researchers saw this coming, said Ostfeld. A complex sequence of ecological boom-and-bust cycles, overlaid on the tick’s own two-year life cycle, created the perfect storm for human disease risk, he said.
It started in fall 2019, when oak trees produced a bumper crop of acorns across much of the eastern U.S. White-footed mice gorged themselves of that surfeit of high-energy food, and in spring 2020 produced a population explosion of their own. Ostfeld said in boom years like 2020, the mouse population can be 20 times higher than a normal year.
That “eruption” of mice, he said, meant it was easier for ticks to find what scientists call their blood meal. More larval ticks survived to to the nymph stage, which is responsible for more than three-quarters of Lyme disease cases in humans.
Nymphal ticks are the main transmitters of Lyme and other diseases for two reasons:
-- They are most active in the summer, when humans are tramping through forests and trails.
-- They’re tiny – about the size of a poppy seed – so they’re harder to see on the skin than the larger adults. The longer a tick attaches unseen to skin, the higher the chance it will pass on diseases.
When tick larvae hatch from eggs in the spring, they are free of disease. They ingest viruses and bacteria from infected mice and other small mammals, and can then pass on those microbes when they feed as nymphs and again as adults.
Another reason for the spike in ticks this year is a pair of consecutive warm winters and springs, Thangamani said. Fewer ticks are killed by the cold, and animals are more active.
“When weather warms up, humans get outside,” he said. “For small mammals like mice, they want to get out of their burrows and look for food. It’s a perfect opportunity for a tick to latch onto a mammal, whether it’s us or wildlife.”
The state health department said odd-numbered years tend to have more ticks than even-number years because of their two-year life cycle.
Add it all up, and 2021 is a particularly bad time to be a human being walking through the forest or grass, where ticks wait to latch onto passing prey.
“Because an abundance of mice in 2020 leads to this boom in nymph stage ticks in 2021 and a crash in the mice in 2021, those ticks are hungrier than usual,” Ostfeld said.
The nymphal ticks will keep feeding throughout the summer, as more people head outdoors and increase their chances of encountering a tick. A tick feeds only three times in its two-year life span: as a larva, a nymph, and finally as an adult. Adult ticks are most active in the fall, as females seek one last meal before winter. Adult ticks are most likely to carry disease because they’ve already fed twice on other animals that might be infected.
While researchers expect that this year’s tick boom will lead to more cases of Lyme and other diseases in humans, it’s too early to confirm that.
“We’re still early in the nymph season,” Ostfeld said. “We’re collecting data as we speak.”
Many cases of tick-borne disease are never reported or confirmed. Even when cases do get reported to state and federal health agencies, it can be months or years before the data is reviewed and released.
Meanwhile, envelopes with ticks inside continue to pour into the Upstate lab. On June 8, 201 ticks arrived in the mail, the highest single-day total since the lab launched the free testing program in April 2019, according to the lab’s Twitter account. The program’s purpose is two-fold: to tell residents if ticks they find are carrying diseases, and to use citizen science to map the distribution of ticks and those diseases.
Since the program began, the lab has processed more than 11,000 ticks. Of those, 80% are black-legged ticks, also known as deer ticks. That’s the species of greatest concern because it carries the Lyme bacterium.
A third of black-legged ticks tested at Upstate contain that bacterium, known as Borrelia burgdorferi. About 10% had bacteria that causes babesiosis, a disease with symptoms similar to Lyme: fever, body pain, headaches and fatigue.
Thangamani said the flood of ticks arriving at the lab isn’t just because more people are hearing about the testing program.
“I talk to some of my peers who are noticing an increase in ticks, up to 50% of deer ticks,” he said. “I did a phone call with some colleagues in Connecticut and Massachusetts, and they see an increase.”
If there’s any silver lining to this year’s tick season, it’s that the risk of getting a tick bite will likely drop in 2022. Fewer ticks are expected to survive this year because of the fall in the mouse population, Ostfeld said.
But ticks and the diseases they carry – up to seven different pathogens have been identified in ticks in New York – are here to stay.
“When ticks are established, they’re going to keep expanding,” said Brian Leydet, an epidemiologist and tick expert at SUNY College of Environmental Science and Forestry. “It’s always going to be worse and worse and worse.”
