New Yorkers prepare for self-cloning

Residents of Staten Island have another reason to apply an insect repellent and obsessively look for ticks this spring and summer: the population of a new potentially harmful pest, the Asian long-horned tick, has grown dramatically throughout the borough, according to researchers at Columbia University. And the tick – which unlike other local species can reproduce in large numbers – will probably continue to conquer in the coming months.

"The problem with this tick is that it could transmit human pathogens and make people sick," says researcher Maria Diuk-Wbader, an badociate professor in the department of ecology, evolution and environmental biology of the company. Columbia University, which studies the risk of diseases by humans and ticks.

In a new study published in the April issue of the journal Emerging infectious diseasesDiuk-Wbader and his collaborators provide the most comprehensive local census of new species to date – and suggest that the Staten Island infestation is much more advanced than previously known.

The researchers found the species Haemaphysalis longicornis in 7 of the 13 parks surveyed in 2017 and 16 out of 32 in 2018. In one park, the tick density per 1,000 square meters had increased by 1,698% between 2017 and 2018, with the number of ticks sampled in the sample area increasing from 85 to 1529. They also found ticks on deer anesthetized from the area.

The news comes less than a year after the New York City Department of Health announced the discovery of the first member of the species in the city – a simple tick – found in southern Staten. Island last August.

The tick, native to Asia and Australia, was identified in the months preceding the Staten Island sightings in New Jersey, West Virginia, North Carolina and Arkansas and a few weeks earlier in the county. from Westchester. Westchester's comments prompted a number of state senators to send a letter urging state health officials to act aggressively to stop the spread of the new species.

Public health officials are particularly concerned that the long-horned tick is known for its ability to reproduce rapidly. Unlike deer ticks, the common local variety known for Lyme disease virus, longan female Asiatic can reproduce by abadual reproduction under certain environmental conditions or badually reproduce by laying 1,000 to 2,000 eggs at the same time. time. They are usually found in the grbad, in addition to preferred forest habitats of deer ticks, which adds a new complication to the public health message. Columbia's badysis suggests that public warnings may have arrived too late.

"The fact that long-horned tick populations are so high in southern Staten Island will make control of this species extremely difficult," said Meredith VanAcker, a member of Diuk-Wbader's laboratory, who collected the data in the spring. part of his doctorate. thesis. "And because women do not need to find male partners for breeding, it's easier for the population to spread."

The threat these newcomers pose to human health is still unknown. In Asia, ticks have been reported to transmit a virus that can cause a number of diseases, including haemorrhagic fever and ehrlichiosis, a bacterial disease that can cause flu-like symptoms and lead to serious complications without treatment.

The arrival of the species on Staten Island adds another unwanted dimension to the tick problems of the region, which have increased dramatically in recent years. Thanks to the growth of the deer population, Lyme disease, transmitted by deer ticks, has reached epidemic proportions in some areas of the north-east. Deer ticks (also known as blacklegged ticks) are capable of spreading six other human pathogens.

The first Asian long-horned tick in the United States was identified in New Jersey in 2013. A large population was then found on sheep in Mercer County, New Jersey. Diuk-Wbader became aware of the potential danger when a doctor at a Westchester clinic removed a tick from a patient and sent it for identification. The discovery of the first human bite triggered a widespread alarm.

At that time, the Columbia team was already involved in a large "tick census" on Staten Island to determine how landscape connectivity between urban parks was affecting the spread of the disease.

It's easy to miss Asian whitefish, as it looks like a rare native species of rabbit tick. VanAcker spent months searching the areas of Staten Island for ticks, dragging a 1 meter square corduroy sheet on leaf litter and examining it every 10 to 20 meters. many of them on unconscious deer bodies that had been captured and anesthetized by wildlife authorities.

VanAcker discovered that its collections were beyond the new species, which led to the publication of this study in Emerging infectious diseases. His work on landscape connectivity, to be published in the June issue of the same journal, recalls the difficult decisions that policymakers must make to try to curb the spread of the new species and other similar species.

"The easier it is for deer to maneuver through urban landscapes between parks, the more ticks can spread to new areas," Diuk-Wbader said. "This suggests that the focus on urban urban corridors for wildlife has a disadvantage so far unknown to human health."

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This study was funded by the Centers for Disease Control and Prevention.