A new species of invasive tick capable of transmitting several serious diseases is spreading in the United States, posing an emerging threat to human and animal health, according to a pair of reports released Thursday.
the The long-horned Asian tick is the first invasive tick to arrive in the United States in about 80 years. Originally from eastern China, Japan, the Russian Far East and the Korean Peninsula, it is also established in Australia and New Zealand.
In August of last year, it was discovered on a 12 year old Icelandic sheep in western New Jersey. Since then, the tick has been found in Arkansas, Connecticut, Maryland, New York State, North Carolina, Pennsylvania, Virginia and West Virginia. The species has been found on domestic animals, livestock, wildlife and humans. According to a report by the Centers for Disease Control and Prevention, there is no indication to date that the tick has spread pathogens to humans, domestic animals or wildlife in the United States.
Public health officials are concerned about the potential of Haemaphysalis longicornis spread diseases. In other parts of the world, it is a major pest for livestock. its stings can make people and animals seriously ill. According to researchers, in some parts of Australia and New Zealand, ticks can suck so much blood from dairy cattle that they drop milk production by 25%.
In Asia, the tick is carrying a virus that causes human haemorrhagic fever and kills up to 30% of its victims. Although this virus is not found in the United States, it is closely related to the Heartland virus, another deadly tick-borne disease that circulates in the United States. Health officials are particularly concerned about the tick's ability to adapt to become a vector of this virus and other tick-borne diseases in the United States.
The tick "is potentially capable of spreading a large number of diseases," said Lyle Petersen, director of the CDC's Vector-borne Diseases Division. "We really do not know if the diseases will be spread by this tick in the United States and, if so, to what extent. But it is very important that we resolve this quickly. "
The female tick can also lay hundreds of fertile eggs without mating, "resulting in a massive infestation of the host," says the CDC report.
The diseases caused by mosquitoes, ticks and flea bites have more than tripled in the United States from 2004 to 2016, according to the CDC. The increase of these vector-borne diseases has many underlying causes: expansion of travel and trade, urbanization, population growth and rising temperatures.
Warming temperatures and climate change make the environment more hospitable to ticks and mosquitoes that spread pathogens and increase the length of the season when ticks are active, Petersen said.
Next week, officials from several federal agencies – including the CDC, the Department of Agriculture, the Environmental Protection Agency, the National Parks Service and the Department of Defense – meet to develop a coordinated national strategy to combat these vector-borne diseases.
"The problems are getting worse," Petersen said, noting that all states, with the exception of Alaska, were experiencing an increase in these diseases. "We are losing this battle."
Officials said they were trying to educate public health officials, health professionals and veterinarians about the potential threat of this species. In addition to the CDC report, Petersen and colleagues published an article in the American Journal of Tropical Medicine and Hygiene highlighting "significant gaps" in the ability of public health systems to cope with these diseases.
Many tick-borne diseases are underreported. There are also no proven scalable measures to control many vector-borne diseases transmitted by blacklegged ticks or deer ticks that spread at least seven human pathogens in the United States. , including the bacteria that causes Lyme disease.
Officials do not know when or how long the horned tick has arrived in the United States. Between August 2017 and September 2018, there were 53 ticks in the United States. The states with the highest percentage of infested counties are New Jersey (33%), West Virginia (20%) and Virginia (12%), including Fairfax County, a suburb of DC Using an analysis retrospectively, scientists believe that the invasion took place years earlier.
Tadhgh Rainey, an entomologist at the Hunterdon County Health Division in New Jersey, discovered the ticks on August 1, 2017, when a woman who had mowed her pet, an Icelandic sheep, arrived at the department. with what she thought were mites on her hands.
On closer inspection, it turned out to be larval ticks. And she was covered with them.
She had them everywhere in her clothes. We are talking about more than 1,000 ticks on his body, "Rainey recalled in an interview. It's a species I had never seen before. Rainey's assistant provided him with extra clothes, and health officials put his pants in the freezer to eliminate the ticks.
While Rainey was trying to identify the species, the woman returned about two weeks later, this time with engorged adult ticks from her sheep. Rainey said that he realized that he had not seen anything before and had gone to visit his farm to see the animal itself.
"I am covered with ticks," he said. "They were encrusted everywhere in the sheep, thousands on the ears, too much to count".
Andrea Egizi, researcher at the Monmouth County tick-borne diseases laboratory at Rutgers University, identified the tick with the help of a DNA analysis. His identity was then confirmed by scientists from the USDA.
Rainey said the tick probably arrived in the United States with a large animal. This part of the state has an active trade of horses and sheep overseas. The affected sheep had never traveled to the outside of the country. "Or it could have happened to someone who has been hiking in nature in New Zealand," he said.
The health department officials were able to kill all the sheep ticks and eliminate them on the woman's property. The sheep, named Hannah, recently died of old age, said Rainey. The health department has the woman's pants because "she still does not want her pants".
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