We all know there are no such things as vampires. However, bloodsuckers exist and you should be alert to their presence. They can be very sneaky. Mosquitoes, three-corner flies, horse flies and many other insects want to make a meal out of you. One of the creepiest and most repulsive bloodsuckers isn’t even an insect! Instead, this organism has eight legs and can’t even fly. Ticks! They have been very abundant this summer and it helps to know something about these parasites.
What lurks in the bushes?
Ticks are Arthropods, organisms that have a hard exoskeleton, jointed legs and no backbone. Insects, spiders and crabs are other arthropods. Ticks belong to the class Arachnida and are therefore closely related to spiders, scorpions and mites. Unlike insects, arachnids have two body parts, eight legs and no antennae. Ticks and mites are further divided into the suborder Parasitiformes as many of them are parasites.
Among ticks, they are grouped into two major categories based on their exoskeleton, hard and soft. Many of the ticks that we are familiar with fall in to the hard-bodied tick category, including the American dog tick (Dermacentor variabilis) and deer or black legged ticks (Ixodes dammini). As you can see in this magnified picture, the American dog tick is much larger than the deer or black legged tick. The American dog tick is slightly smaller than the size of a pencil eraser. These ticks feed mostly on mammals and often have different host preferences throughout their life stages. Young deer ticks, for example, feed on many different hosts while the adults are dependent on deer. Female deer ticks require a large 3-day supply of blood from a deer prior to laying up to 2,000 eggs. Soft ticks prefer bird and reptile hosts and often will be species specific when it comes to host food. All ticks are bloodsucking parasites. Ticks are usually limited to habitats frequented by their hosts. Woods, tall grass, and shrubby vegetation provide ideal feeding and hiding habitat for hosts and also are places for ticks to climb, crawl and wait for a passing meal. Ticks are able to sense trace changes in carbon dioxide left by warm-blooded animals from a distance. They even select ambush sites based on their ability to identify well-traveled paths. Once on a host, they seek protected areas and sink their mouthparts into the flesh to feed. When full, the tick simply drops off the host.
There are four stages in the life cycle of a tick: egg, larva, nymph, and adult. It generally takes several months to two years to complete this life cycle. Some ticks may live to be 3 years old so in any given year there may be several generations of ticks present at any one time. Prolonged winter cold will kill many ticks. The past mild winter is certainly one of the reasons ticks are abundant this summer. Warm temperatures in early spring also benefited these creepy crawlies. Humans and other animals are prone to several diseases transmitted by ticks. Ticks normally become infected by taking a blood meal from an infected animal. When an infection moves from an animal host to a human it is called zoonosis. Lyme disease and Rocky Mountain spotted fever are two examples of tick-borne diseases. It is important to note that an infected animal or person cannot pass the infection on to another animal or person. (Ohio Health Department http://www.odh.ohio.gov/odhPrograms/dis/zoonoses/vbdp/vbtick.aspx)
Rocky Mountain spotted fever (RMSF) is caused by bacteria called Rickettsia rickettsii. In Ohio, the bacteria are carried primarily by the American dog tick. Not all ticks are infected and an infected tick is usually attached to the host for four to six hours before it transmits disease. This species of ticks are the most commonly encountered ticks in Ohio and are often found in overgrown lots and along weedy roadsides, paths and hiking trails. Ohio reports between one and 33 cases of RMSF each year, although most occur in southeastern Ohio. Symptoms appear about one week after the bite of an infected tick, and may include high fever, headache and aching muscles. Within a few days, a pink, non-itchy rash forms on the wrists, forearms and ankles. If you suspect these symptoms, it is important to receive the appropriate medical care as soon as possible.
Another tick borne disease that is becoming more prevalent in Ohio is Lyme disease. Lyme disease is caused by bacteria called Borrelia burgdorferi. Although Lyme disease is found more frequently in Northeastern and upper Midwest states, cases have been reported in Ohio since 1984. In Ohio, the bacteria are transmitted to humans by the deer tick. An infected tick is usually attached to the host for 36 to 48 hours before it transmits disease. The risk of exposure to deer ticks is greater in wooded or brushy areas, and in the edge area between lawns and woods. Although Lyme disease transmission in Ohio remains low, deer ticks are becoming more established and the number of cases in could increase. Symptoms of Lyme disease may appear between three days to a few weeks after a tick bite, but some symptoms may not appear for months or years. A circular, ring-like rash usually forms. Fever, fatigue, headache and joint pain is also common. Lyme disease responds to appropriate antibiotic therapy and early detection and treatment is important to avoid other complications.
An ounce of prevention
Contrary to popular belief, ticks do not jump, fly or fall out of trees. They wait on low growing plants for a host to pass by. When a person or animal brushes against the vegetation, the tick will cling to fur or clothing and crawl upward, looking for a place to attach and begin feeding. In humans, ticks often seek areas behind the knees, the crotch area, neck and head. You can reduce your exposure to ticks and disease by following these simple steps:
• Avoid tick-infested areas such as tall grass and dense vegetation.
• Tuck your pants into sock tops or boots.
• Wear light-colored clothing to make it easier to find crawling ticks.
• Use repellants and follow label instructions carefully.
• Check yourself, your children and pets frequently for ticks.
• Bathe or shower after exposure to tick habitat to wash off and more easily find ticks that may be crawling on you.
• Dogs are also at risk for tick-borne diseases and they may carry infected ticks into the home. Infected dogs are not contagious to humans but keeping them on a treatment to control ticks is advisable.
• If you do find a tick embedded in your skin, carefully slide a pair of tweezers under the tick near the mouth and firmly pull up.
For more information about ticks in Ohio, visit the Ohio Department of Natural Resources website at http://www.dnr.state.oh.us
Did you know…
If you suspect that the tick bite may result in the transmission of disease you need to keep the tick in good condition so that the tick can to be tested as the disease carrier. Without this evidence it can be difficult to obtain treatment. Simply wrap the tick in a moist paper towel and place it in a Ziploc bag in the fridge. If symptoms arise, you can take the tick to your health care professional.
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Matt Sorrick is Director of The Center for Science Education at Hiram College. Joe Malmisur is an executive member of the Northeast Ohio Forestry Association and amateur naturalist.