By Matt Reese
It was not the first time, and probably will not be the last. This summer, Morgan County Extension educator Chris Penrose came into his office to find a jar of some questionable critter to identify. In many cases, the contents of the jars prove to be unremarkable. That was not the case with this one.
“When I opened it up, I saw a whole bunch of ticks in there and I said to myself, ‘uh oh,’” Penrose said.
After sending samples from the jar for further analysis in Columbus, Penrose’s suspicions were confirmed: the Asian longhorned tick had made its way to Morgan County cattle pastures.
The Ohio Department of Agriculture (ODA) announced in the summer of 2020 the United States Department of Agriculture’s National Veterinary Services Laboratory confirmed the discovery of an Asian longhorned tick in Gallia County. The tick was found on a stray dog. The tick was identified by Ohio State University and sent to the federal lab for confirmation.
The Asian longhorned tick is an exotic East Asian tick that is known as a serious pest to livestock. U.S. Department of Agriculture first confirmed the presence of this tick in the U.S. in New Jersey in 2017. Asian longhorned ticks are light brown in color and are very small, often smaller than a sesame seed. An adult female is about the size of a pea when full of blood. Larva, nymph and adult may all be present at the same time.
Asian longhorned ticks are difficult to detect due to their size and quick movement. They are known to carry pathogens, which can cause disease in humans and livestock, and may also cause distress to the host from their feeding in large numbers, in some cases causing death. Since first discovered in Ohio, the Asian longhorned tick has been spreading.
“I think last year they were found over in Monroe County and maybe another county in southern Ohio,” Penrose said. “We kept it in the back of our minds to keep an eye out for it. When the jar came in that’s what stimulated my interest and, of course, the interest of our local veterinarian.”
Along with all the creepy traits common to ticks, Asian longhorned ticks can reproduce asexually.
“They don’t need a mate to reproduce,” Penrose said. “Each tick can lay up to 2,000 eggs so you can see how fast they can expand and basically overwhelm a cow. I think these numbers can build up so fast and so much that that they can actually suck enough blood out of a cow to kill her.”
This was obviously a concern for the cattle producer behind the tick-filled jar at the Extension office.
“Earlier in the summer, the farmer did notice a few ticks on some baby calves when he went out to work them after they were born. He didn’t think much about it, but then later on he saw some of his cattle with a whole bunch of ticks on them. Our local veterinarian went out and was able to treat them. The farmer ended up moving the cattle over to another field. A lot of the discussion has been about how these ticks multiply rapidly, but they don’t travel very far. More nymphs were found this fall, but they got it under control for this season. Farmers right next door that had cattle didn’t have any issues with them whatsoever,” Penrose said. “And not only our local veterinarian, OSU Extension and OSU veterinarians get involved with this but also our friends at the Ohio Department of Agriculture and our USDA veterinarians got involved. We informed the local health department about it too. It was really comforting that there was a team of different agencies working together to really get a handle on this.”
While tick season is winding down late in the year, it remains important to monitor livestock for Asian longhorned ticks (and the potential for disease they spread) while there is time to come up with a strategy for 2023. In cattle, check for ticks where the skin is thin on the head, neck, ears, flanks, armpit, groin, udder, and under the tail.
“There are some insecticides or some pour-ons that can be used, but there may be some resistance to some certain types. Another problem is that a lot of the pour-ons we use are not labeled for ticks, even though they work on ticks,” Penrose said. “That’s why it’s so important to have a good veterinary client-patient relationship with a veterinarian if you’re fortunate enough to have one in your area so you can come up with a solution. Some of the Ivomec-type products will work for an extended period of time, but others may not. If it’s really bad, you maybe should consider something like a back rubber that has an insecticide with it that you could put out next to the mineral tub or the water source.”
Ticks move by hitching a ride on something else.
“They can move on wildlife, people, equipment, anything. That’s kind of what makes it scary. You need to not only check your cattle but your goats, your sheep, your dogs, and cats. It’s really important to have pets on one of those good, preventative medicines to keep ticks off our animals,” Penrose said. “They’re still trying to learn about this, but it certainly can be a problem. We need to figure out how to keep these ticks from spreading. We need to really keep an eye out because problems are much easier to solve if you can get on them early rather than when it gets to be too late for the livestock. This is a developing situation that hopefully we can learn more from and really not cause any additional problems to livestock.”
In Kentucky, the bite of the Asian longhorned tick is being blamed for cattle with a microscopic protozoan parasite (Theileria orientalis) that infects the red blood cells of cattle and causes anemia. The problem can also be transmitted through blood transfer from contaminated needles and equipment.
“The tick can feed on many animal species, including humans, but the blood parasite only affects cattle. Once a cow is infected, it may take 1 to 8 weeks before she shows symptoms of disease,” said Michelle Arnold, with the University of Kentucky Veterinary Diagnostic Laboratory. “There is a spring peak in disease incidence in March-April and a fall peak in September-October. There is no effective treatment for sick cattle or vaccine to prevent infections. However, once infected, cattle become carriers and are protected from new infections. There are no recognized long-term health or production effects from persistent infection. Theileria is not a public health concern and contact with affected cattle doesn’t pose a human health risk or food safety risk.”
With regard to Theileria, Arnold suggests cattle producers watch for the following:
• The majority of infected cattle have limited or mild clinical signs. The symptoms are very similar to anaplasmosis, another tick-borne cattle disease that causes anemia.
• Affected cattle show signs of anemia including lethargy, pale or jaundiced (yellow) mucous membranes, and increased respiratory and heart rates. Labored breathing may be mistaken for pneumonia, especially in young stock.
• Affected cattle may be exercise intolerant and lag behind the rest of the herd or be off by themselves.
• Affected cows may be off feed, have a fever, and sudden weight loss.
• May see sudden death, especially in late pregnant and early lactation cows.
• Late term abortions may occur due to lack of oxygen to the fetus with subsequent death of the calf. Metritis in the cow can follow. Breeding bulls may have decreased libido for 1 to 1.5 months.
• Calves, especially 6 to 8 weeks of age but up to 6 months of age, may show symptoms.
For cattle with signs of anemia Arnold suggests:
• Contact a veterinarian. Theileriosis and anaplasmosis look almost identical, so treatment with an approved antibiotic (LA-300 or Baytril 100-CA1) for treatment of anaplasmosis is recommended. However, if Theileria is the cause, there will be no response to the antibiotic therapy. A blood test is available to test for this disease.
• Stress and movement of affected animals should be minimized, as their reduced number of red blood cells lowers their ability to transport oxygen around the body. This can lead to collapse and death. Affected animals should be rested, given high quality feed and water, and handled only when necessary.
• There is no treatment available for Theileria infection other than supportive care. Blood transfusions may be used for valuable animals. Recovery may take 1 to 2 months depending on the severity of the anemia.
• Ease any underlying disease or stress. Cows in late pregnancy, early lactation and young calves (2 to 3 months old) are more susceptible to severe disease. Pay close attention to cows around calving, avoid trace mineral deficiencies, and vaccinate cattle against the immunosuppressive BVD virus.
For controlling Asian longhorned ticks Arnold said:
• Ticks spend most of the time, nearly 90%, in the environment. Even though only a small proportion of the tick population is on livestock at any one time, treating cattle with a tick repellent will reduce the numbers that feed and develop into the next stage of the tick lifecycle. This will have an impact on the numbers of eggs that eventually get deposited in the pasture and helps manage the disease spread. Currently there are no acaricides labeled for use against Asian longhorned ticks. The use of pesticide impregnated ear tags, pour-ons, sprays, and back rubs that control the American dog tick and the Lonestar tick should provide beneficial tick control. There are field reports of success with macrocyclic lactone dewormers such as Cydectin Pour-on and Dectomax Injectable products.
• Environmental control to reduce contact with ticks involves mowing pastures, especially shaded areas, and fencing cattle from wooded areas. Perimeter fencing of a minimum of 20 feet from wooded areas will reduce the number of ticks on the grazing area. All stages of the tick like warm, damp conditions and long grass. Avoiding long rank pasture that has not been grazed such as around the edge of crops and brushy areas will reduce the likelihood of animals picking up ticks. Keep in mind that wildlife can serve as tick hosts and move the ticks to new areas.
• Treat new cattle for ticks as they arrive to the farm and before moving cattle from one property to another to avoid movement of infected ticks.
• Calves should be closely inspected for ticks and signs of anemia, too.
Ohio State University Extension has a fact Sheet on Asian longhorned ticks at: https://ohioline.osu.edu/factsheet/vme-1035.