Ticks and Tick-borne Diseases

Our July edition of Tree-Talk focuses on ticks and tick-borne diseases.   Our special guests this month are ANR Educators Tim McDermott, DVM (Franklin County) and Marcus McCartney (Washington County).  Check out these videos to learn how you can protect your family, pets and livestock from the increasing threat of ticks and the diseases that they carry.

Full episode (29 minutes) including Marcus McCartney’s personal experience with Lyme disease: https://youtu.be/bKkTeJozh1U

Protecting yourself from ticks (3:30 minutes): https://youtu.be/3AwOzLxk5_g

Tick removal (3:41 minutes): https://youtu.be/9HPAuG8cS9Y

 

Useful websites:

https://u.osu.edu/tick  (click on the tick tab on the top left of the page)

https://tickencounter.org

http://tickreport.com

As Ticks Spread, New Disease Risks Threaten People, Pets and Livestock

One tick that a new study shows is endangering cattle in Virginia is able to clone itself, making colonizing new locations that much easier.

A lone star tick. To find a host, some ticks grope about with their forelegs from a leaf or grass blade, a behavior known as "questing." Credit: Smith Collection/Gado/Getty Images

Lone star ticks have been ranging farther north and west in recent years. When they bite, the aggressive ticks can spread diseases and even make humans develop a severe allergy to red meat. Credit: Smith Collection/Gado/Getty Images

It didn’t take long for one of America’s newest tick species to find Thomas Mather.

Mather, an entomologist who specializes in the tiny disease-carriers, had taken a team of scientists to Staten Island, New York, in hopes of collecting at least one Asian longhorned tick.

They were all of 50 feet from their car and had just unfurled a banner of white fabric, known as a tick drag, when the first longhorned tick landed in the fabric. Dragging a nearby patch of grass with the fabric, more longhorned ticks appeared. On a grass blade, Mather spotted an unusual clump and discovered dozens of tiny, seed-like tick larvae waiting for a victim to brush past.

If the Asian longhorned tick was unheard of in America just a few years earlier, it wasn’t a stranger here anymore.

Since 2013, the Asian longhorned tick has popped up in at least 11 U.S. states, mostly in the Northeast. Previously limited to Asia, Australia, New Zealand and some Pacific Islands, it likely found several ports of entry to North America, hitching a ride on animals or humans. Its ability to clone itself without a mate made colonizing new locations that much easier.

While the longhorned tick is still feeling out its range in North America, other established tick species are expanding theirs as the climate changes and the planet warms—with consequences for humans, pets and the livestock industry.

Several tick species have spread to new areas of the country, some carrying diseases that can pose serious health risks to humans, including Lyme disease, which can affect the joints, heart and nervous system, and Rocky Mountain spotted fever, a treatable but potentially fatal disease that causes fever and muscle pain.

An aggressive tick called the lone star, which has been creeping north and west from its original habitat, can transmit an illness similar to Lyme disease, as well as pass along a sugar molecule that can make humans develop severe allergies to red meat.

Infographic: Lonestar Tick: Its Range, Diseases and Biting Behavior

While the total number of tick-related illnesses is difficult to gauge since so many go unreported, the trend is clear. The number of cases of reported tick-borne diseases has been on the rise in the U.S., doubling from 2004 to 2016, and reached a record high in 2017, the latest annual data reported by the U.S. Centers for Disease Control and Prevention (CDC).

Higher temperature associated with climate change is one key factor affecting where, and how fast, ticks colonize new places, the National Climate and Health Assessment says.

Livestock Industry Faces a New Threat

Ticks can jeopardize animals’ health, too, and the longhorned species could become a formidable threat to the cattle industry, scientists said.

The longhorned tick is already suspected of killing cattle on farms in three separate Virginia counties by infecting them with Theileria orientalis, a parasite that causes fever, anemia, jaundice, and other symptoms in animals.

In a study published last week about the infections, researchers warned that the tick could put the Virginia cattle industry at risk. Once an animal becomes infected, there is no treatment or cure.

Infographic: Asian Longhorned Tick

Scientists warn that the longhorned tick could proliferate quickly, and since females can reproduce without a mate, ordinary ways of controlling pest population, like sterilizing males, won’t work. A single tick can populate a new location.

“As of right now, we don’t have a great way to stop that spread,” said Kevin Lahmers, a veterinary pathologist at the Virginia-Maryland College of Veterinary Medicine, who co-authored the new study, published by the CDC.

Several research teams are collaborating with the U.S. Department of Agriculture on research and surveillance of the tick, and researchers are studying the tick’s range in other countries to try to determine its potential distribution here.

Ticks in More Places

In general, ticks are expanding their ranges, Lahmers said. In Virginia, 15 to 20 years ago, Lahmers said he only saw dog ticks. Now, deer ticks—which can carry Lyme disease—are the predominant tick species there.

Infographic: Blacklegged Tick

Fluctuating climate and weather patterns can significantly affect diseases carried by ticks, as well as those carried by mosquitoes, said Ben Beard, deputy director of CDC’s Division of Vector-Borne Diseases.

With an increasing number of days without frost, for example, the risk of disease transmission starts earlier and extends later into the year. “If you look at climate change models and see how those models are advising those areas of risk, clearly there’s an impact that it’s having,” Beard said.

Infographic: American Dog Tick

In Germany, a tropical tick called hyalomma seems to have survived its first winter there, according to Ute Mackenstedt, a professor of parasitology at the University of Hohenheim, Stuttgart. Her team discovered the tick this year too early in the season to have been brought over by migrating birds.

“We expect new ticks species in Germany due to changing weather conditions,” Mackenstedt said. She said the hyalomma tick could become the second recently introduced species typically found in warmer conditions to establish a population in Germany, though it’s too early to be sure.

Hyalomma can transmit the Ebola-like Crimean-Congo hemorrhagic fever virus, though that virus hasn’t yet been found in Germany.

Preventing Tick Bites — at Home and in the Woods

The longhorned tick is able to spread a virus known as SFTS, or severe fever with thrombocytopenia syndrome. It can be fatal, particularly for people over 50, but it hasn’t yet turned up in the U.S.

The CDC urges precaution against all tick species, not just the longhorned.

“There’s a huge potential here for this tick to further complicate the problems we’re already having,” said Beard of the CDC. “It’s one of those things we can’t afford to ignore, but at the same time, we have to work on the problems that are already here.”

Crowd-Sourcing Tick Research

Several research efforts are gathering data about the spread of ticks from people who photograph or mail in ticks they’ve found. Mather runs one of those efforts, a website through the University of Rhode Island called TickSpotters, where his team of researchers fields questions from people who submit photos and samples to be analyzed.

He said there’s been a clear increase in submissions over the past few years: From the site’s inception in 2014 until 2017, he saw fewer than 8,000 entries. Last year alone, he saw nearly 15,000.

Infographic: Rocky Mountain Wood Tick: Its Range, Diseases and Behavior

One reason may be that ticks are spreading to new places. Mather said contributors frequently ask, “What’s going on? I’ve lived in this place for 15 years and never seen a tick before.”

Building a database of these findings can help researchers understand tick distribution patterns.

“It’s people that are encountering ticks a lot more than scientists,” Mather said. “TickSpotters has a chance for using the power of the crowd to help understand what’s going on.”

Ohio Vector-borne Disease Update 07/12/2019

As of 07/11/19, 5,389 of 5,642 pooled mosquito samples (170,866 Culex spp. total) have been tested and 7 samples were positive for West Nile virus (WNV) from Franklin (5), Ross (1) and Summit (1) counties. Below is a graph of the minimum infection rate (MIR) in Culex spp. mosquitoes collected in Ohio. As you can see, the MIR is below where it was at this time last year. No human cases have been reported so far.

While WNV activity in Ohio is currently low, in the past week, several suspected cases of La Crosse virus disease have been reported. Although these cases are pending confirmatory testing, this suggests La Crosse virus activity is ongoing in Ohio. Please ensure you continue with your community and public education efforts focusing on personal protection to avoid mosquito bites and source reduction to prevent mosquito breeding.

For more information, see the current Ohio vector-borne surveillance update at www.odh.ohio.gov/vectorupdate.

NOTE: Since Internet Explorer is no longer being supported, ODH’s new webpage is best viewed in other browsers (e.g. Microsoft Edge, Google Chrome, Firefox, etc.).

Please do not hesitate to contact the Zoonotic Disease Program (614-752-1029, option 1) if you have any questions.

Ohio Vectorborne Disease Surveillance Update

The Ohio Department of Health (ODH) Zoonotic Disease Program, in partnership with ODH Laboratory, local public health partners and sanitary district partners, collects and tests mosquitoes and ticks from many communities in Ohio as part of statewide vectorborne disease surveillance.  This surveillance also includes monitoring for human and veterinary cases as well.

Collections of mosquitoes are identified and tested at ODH Laboratory, while ticks are identified by ODH entomologists.  Results from mosquito and tick identification and testing are shared with our partners who use the information to guide public health interventions.

We will monitor for mosquito infections and tick findings throughout the summer and fall and will report positive results and summary statistics on this website, updated each Friday at noon.  Please download the attached document for a more detailed summary of mosquito and tick surveillance in Ohio.

2019 Numbers At-A-Glance

As of July 3, 2019

West Nile virus

Infographic: West Nile virus surveillance statistics

La Crosse/Unspecified California encephalitis virus

Infographic: La Crosse/unspecified California encephalitis virus surveillance statistics

Travel-associated mosquito-borne diseases

Infographic: Travel-associated mosquito-borne disease surveillance statistics

* Ohioans traveling to areas where local transmission is occurring should be aware of the ongoing situation and make every effort to avoid mosquito bites.  Additional information can be found from the Centers for Disease Control and Prevention (CDC)’s Travelers’ Health and Pan-American Health Organization websites.