Monday, 6 August 2018

An Invasive New Tick Is Spreading in the U.S.

An Invasive New Tick Is Spreading in the U.S.


An Invasive New Tick Is Spreading within the U.S.
For the primary time in 50 years, a replacement tick species has arrived within us — one that in its Asian home territory carries fearsome diseases.
The Asian long-horned tick, Haemaphysalis longicornis, is spreading rapidly along the Eastern Seaboard. it's been found in seven states and within the heavily populated suburbs of the latest York City.
At the instant, public health experts say they're concerned, but not alarmed.
Although domestic American ticks are a growing menace and transmit a dozen pathogens, no long-horned ticks here have yet been found with any human diseases. In Asia, however, the species carries an epidemic that kills 15 percent of its victims.
For now, the new arrivals are considered a greater threat to livestock.
Known in Australia as bush ticks and in New Zealand as cattle ticks, long-horned ticks can multiply rapidly and suck such a lot blood from a young animal that it dies. The ticks bloat up like fat raisins until their tiny legs are barely ready to support them.
After a feed, females can lay many fertile eggs without mating.
“One tick can grind out females in fairly large numbers,” said Thomas Yuill, a retired pathobiologist at the University of Wisconsin, Madison, who was one of the primary to boost alarms about the invaders.
The first long-horned tick was found last summer in western New Jersey. This summer they were collected publicly parks and golf links in Bergen, Union, and Middlesex counties in New Jersey, and in wooded and grassy areas of the latest York’s Westchester County.
They were reported in Pennsylvania for the primary time last week, and are sighted in Arkansas, North Carolina, Virginia and West Virginia.
They were found feeding on horses, dogs, deer, a calf, a sheep, and an opossum. they are doing bite humans, but it's not clear how often.
People should use equivalent precautions they are doing against domestic ticks, experts said, like using repellents and checking for ticks after walking through woods or tall grass.
Tadhg Rainey, an entomologist at the general public health department of Hunterdon County, N.J., found the primary long-horned ticks within the country last August when a lady who had been shearing her pet Icelandic sheep came to his department with ticks on her hands and wrists.
“I thought she’d have a couple of,” Mr. Rainey said in an interview. “But she was covered in them, easily over 1,000 on her pants alone.”
Most were young nymphs about the dimensions of dust specks. “She had a change of garments in her car, so we put her clothes within the freezer to kill them,” Mr. Rainey recalled.
The ticks didn’t match any North American pests, and initially, he couldn't identify them. The woman’s 12-year-old sheep was penned alone and had never traveled, so where they came from remained a mystery.
A month later the lady called again to ascertain if he had found out what they were, and Mr. Rainey drove bent to see the animal for himself. “A minute after we entered the paddock, even before I touched the sheep, I used to be covered in ticks,” he said.
The sheep was weak from blood loss, so he gave the owner some insecticidal livestock wash. The grass around the paddock was later cut and therefore the area sprayed in an attempt to eliminate the outbreak.
Andrea Egizi, an entomologist at Rutgers University, finally identified the longhorns by DNA analysis. Her lab has now tested quite 100 specimens found in NY and New Jersey.
Thus far, Dr. Egizi said, none have any of the pathogens causing the six diseases she screens for: Lyme disease, recurrent fever, babesiosis, anaplasmosis, and two sorts of ehrlichiosis.
The Centers for Disease Control and Prevention lab in Fort Collins, Colo., has screened about 100 long-horned ticks for 3 dangerous viruses — Powassan, Heartland and Bourbon — and everyone came up negative, said Ben Beard, the agency’s deputy director of vector-borne diseases.
The lab now has 10 live long-horned ticks and is feeding them to make a colony, Dr. Beard said. which will take a few years, then researchers can determine whether or not they can transmit Rocky Mountain rickettsial disease and other diseases.
In East Asia, long-horned ticks do carry pathogens associated with Lyme et al. found in North America. But the most important threat may be a phlebovirus that causes S.F.T.S., for severe fever with thrombocytopenia syndrome.

(Thrombocytopenia means abnormally low levels of platelets, which help the blood clot; a severe drop triggers internal bleeding and organ failure.)
The syndrome has an overall death rate of about 15 percent, said Terry A. Klein, an entomologist working with the American military in South Korea. But S.F.T.S. is more lethal to people aged 60 or older, killing half them.
However, the syndrome isn't found in Australia or New Zealand, earlier stops for the long-horned ticks as they spread from Asia. In those countries, they cause babesiosis and theileriosis in cattle but are mostly “of nuisance value” to humans, said Dr. David Thomson, a veterinarian in Queensland, Australia.
It’s not clear that the S.F.T.S. virus, which is said to the Heartland virus found during a number of yank states could get established during this country, because its transmission cycle is unknown — it's going to need quite, one host.

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