Tick Season Has Arrived!

by Helene McKernan, Clinton Co .Extension,

Living in Beech Creek my horse herd, dogs, cats, and family have been experiencing tick problems for about four years.  It is not uncommon for us to remove four or five ticks each day from one of our pets, especially our horses, or even ourselves.  Members in the Clinton County horse community have had horses’ diagnosed with Lyme disease and know the devastating symptoms and the cost of treatment of the disease.  I have attended some lectures by recognized veterinarians to learn more of the disease and have been surprised to hear that some feel horses can contact Lyme disease and others feel that horses do not.  What all the lecturers agree upon is that more research is needed to fully understand Lyme disease in horses.  Given the fact that numerous horses have been diagnosed with Lyme disease in this area by recognized veterinary facilities, I will take the aggressive attitude that horses can be afflicted with Lyme disease.  Even if the tick does not cause a disease it is frustrating for me to think that a tiny creature is drinking my horse’s blood!

It is helpful to understand Lyme disease when you understand the stages of the tick’s life cycle.  There are ticks of many varieties and all ticks have three developmental stages: larvae, nymph and adult.  The tick that causes the most concern is the “deer tick” or “black legged ticks”, for when bitten by a deer tick that is inflicted with the spirochetal bacterium Borrelia burgdoferi, it can lead to Lyme disease.  Does this mean that all deer ticks that bite and attach to a host have the bacteria that will cause Lyme disease?  No it doesn’t, but one cannot tell if the tick is a danger just by its appearance.  The deer tick is not selective in its host, for it is attracted to a variety of wild and domestic species, including humans.  Rodents, cats, dogs, birds, cattle and yes even horses can be bitten by the deer tick. 

So let us begin with the larvae stage.  During the larvae stage the tick is about the size of a small “dot” and is ready to look for a host victim.  Immature deer ticks hatch from eggs and can become infected with Borrelia burgdorferi if they take a blood meal on a rodent which had already been infected with Borrelia burgdorferi.  This tick then may transmit the infection to new hosts when it takes subsequent blood meals.  When the tick attaches to the host it begins its blood meal, meaning that it engorges its head into the host and absorbs the blood of the host.  The larvae must have a blood meal before they molt or change into the next stage.  They live for 2 years even during the winter months.  The ticks attach to a host and feed for 12-24 hours before they can transmit the bacteria to infect the new host.  The nymph stage begins after feeding.  The larvae drop off their host and molt or transform into a nymph usually in the fall.  The nymph remains inactive during the winter and then in early spring becomes active again.  The nymph, if infected in its larvae stage, attaches onto another host and feeds for 4-5 days where the body of the tick will swell with blood.  This leads to the adult stage.  The nymph drops off the host and molts into an adult.  The adults seek new hosts throughout the fall hiding in tall grasses and they become inactive.  When temperatures rise they begin looking for a host in an effort to obtain a blood meal and mate and reproduce.  Adult female ticks attach to the host for about a week and feed, whereas males feed only intermittently.  Mating may take place on or off the host and is completed only after a blood meal.  After mating, the female drops off the host and lays eggs beneath leaves and grasses.  The eggs hatch in the summer and the two-year cycle begins again. 

We examine our pets daily and can feel the small bump that usually predicts an attached tick.  Brushing will not remove the tick, but by using tweezers and grasping as close to the host’s skin as possible grasp the head of the tick and pull straight back taking care not to break the blood body pouch.  Difficulties may arise if the head of the tick remains in the host and only the body is removed.  Apply antibiotic ointment to the attachment site if the tick mouthparts break off and remain in the site, or if there is an open wound.  Remember if the tick is removed before the 12-24 hour time period the chances of contacting Lyme disease is slim.  Unfortunately, we often do not know how long the tick has been attached and that is where extreme concern should be noted. 

Prevention of Lyme disease in humans, dogs, and cats has been addressed for years.  Tick repellents containing the chemical permethrin are especially effective in preventing the tick from attaching.  Sprays and ointments can be used on humans and your veterinarian can supply you with applications for dogs and cats that can help prevent tick attachments.  There has not been much research done on Lyme disease in horses and it is debated on whether a horse can get Lyme disease.  It has been found that 75% of horses living in areas with high concentrations of ticks will test positive for antibodies to the organism, which makes it difficult to know if the horse has Lyme disease or not.  Horses living in areas infected with ticks may go on to develop symptoms of Lyme disease or may remain clinically healthy.  Lyme disease occurs in less than 10% of the horses where the tick has attached, for not all ticks carry Borrelia burdgorferi.  

The symptoms of Lyme disease in horses are a fever, shifting lameness that can’t be explained by injury or work level, poor performance, personality changes, laminitis (founder), arthritis, edema, joint swelling, eye inflammation and encephalitis.  Since the symptoms are the same as in many other horse ailments it makes it difficult to accurately diagnosis the disease, plus symptoms can take a long time to develop.  A blood test must be obtained and the results can indicate the horse has been exposed to Borrelia burgdorferi, but not to whether it is a current active infection.  Lyme disease is treated with antibiotics which last over several weeks.  A response to the therapy is usually observed within 2-5 days after start of treatment.  The antibiotics may be administered orally, intramuscular or intravenously.  Often anti-inflammatory drugs and/or medicines to help replace the normal intestinal bacteria killed by the antibiotics are given to the horse.  Unfortunately, there is not a vaccine for Lyme disease currently licensed for horses.  With continued research it is the hope that vaccines may be available for both horses and humans in the near future.

When we first started noticing ticks on our pets and horses I would ask my other horse friends if they were having any difficulty.  For a few years most said no, but last summer and already this year I have had numerous horse owners complaining of finding ticks on their horses.  I wish that others in Clinton County did not have to experience the aggravation of the tick infestations as we have for the past few years, but I’m afraid that all of Clinton County now has a tick problem.  It is annoying to find and remove the ticks, but I’ve been lucky that none of my horses or pets have developed the symptoms that are associated with Lyme disease.  What is also annoying is the mark the tick bite may leave behind.  Sometimes there is not a sign of where the tick is after removal, but more often than not there is a loss of hair around the area and a scabby bump.  This can cause a problem when one is trying to maintain a beautiful coat covering for showing purposes.  One thing I have noticed is that if I observe my horses they can sometimes help me locate the tick that has attached to them.  Often the horse will begin biting at a certain location on their body and he/she will itch aggressively the location where a tick is embedded.  I’m beginning to notice that March, April, May, and June, then Oct, Nov, and Dec are the main times when multiple tick attachments are found.  The tick does not seem to have a preferred time of day or weather condition in which to attach-they find a host on sunny, rainy, cool and warm days.  I have noticed that the ticks are more select in the parts of the horse they like to attach on.  We find the majority of tick bites on the neck, chest, throat, ears, jowl and chin of the horse.  It is funny that most ticks attack my mares in these areas, whereas the lone gelding in the herd seems to find the ticks like his genital areas the best.  At first it was not an easy task removing the ticks in this area, but I honestly think that he and all my horses are pleased when we remove the tick as exhibited by their tolerance during tick removal.  I have found that placing a small dab of “Swat” or some other type of antibiotic ointment helps heal the wound quicker and seems to help the hair grow back faster (if the hair is missing).  This ointment also seems to help keep other pests, such as flies, from being attracted to the site.  If the horse continues to itch, I apply an anti-itch cream, which seems to ease the urge to rub and itch.

The final thing I must remember after removing the tick is that it is not dead and I must find a way to end its life before it can attach to another host.  I keep a baggie in the barn and place the removed tick(s) in the baggie and completely seal it.  I then burn the baggie with the removed ticks.  With four horses, three dogs, and numerous cats it is not uncommon to have to dispose of ten or more ticks a day.  You may be thinking, doesn’t she apply some tick repellant on the dogs and horses to keep the ticks off?  Applying the tick repellant, which we do, does cut down on the number of ticks we have to remove, but we are still finding occasional ticks on the dogs and cats and nothing appears to help with ticks on the horses.  I hope this does not mean the ticks are developing a resistance to tick repelling products!  I feel that I just happen to live in an area that has an enormous tick concentration. 

If you are experiencing tick issues with your pets I suggest that you discuss prevention and treatments with your veterinarians.  The local veterinarians in the Lock Haven area have been extremely helpful in assisting me in assessing the tick issues and assisting me in treatments and preventions.