by David Moore
Manager of Technical Services and Board Certified Entomologist
with contributions by Eric Smith, PhD, BCE
While enjoying the outdoors this year, make sure you are taking steps to prevent bites from ticks. Ticks can infect humans with bacteria, viruses, and parasites that can cause serious illness. Reduce your chances of getting a tick-borne disease by using repellents, inspecting yourself for ticks, and showering after being outside. If you have a tick bite followed by a fever or rash, seek medical attention.
Why should I care about ticks?
Ticks are considered to be second worldwide to mosquitoes as vectors of human diseases. There currently are no vaccines against disease agents transmitted by ticks available to the public. Ticks can carry and transmit a number of pathogens such as bacteria, spirochetes, rickettsiae, protozoa, viruses, nematodes, and toxins.
Ticks are among the most efficient carriers of disease because they attach firmly when sucking blood, feed slowly, and may go unnoticed for a considerable time while feeding. Ticks can take several days to complete feeding on a host. Here is a quick snapshot of some of the most common diseases that ticks transmit in the Mid-Atlantic Region:
Lyme Disease
Lyme disease starts off as an oblong rash, with a clear center that develops at the site of the tick bite, although only 70% of people develop this symptom. Many people refer to this as a bullseye rash. Many people usually develop flu-like symptoms such as nausea, headache, fever, and general stiffness of the neck joints. Chronic symptoms of a small percentage of untreated people include arthritis and nervous system complications. The tick needs to be attached for 36 hours to transmit the disease. The deer tick is the only carrier of Lyme disease in the Eastern U.S.
Rocky Mountain Spotted Fever (RMSF)
A tick needs to be attached for four to six hours in order to transmit RMSF to a human host. The first symptoms are usually headache, chills, fever, muscle aches, nausea, vomiting, and other flu-like symptoms. These first symptoms usually start 2 to 12 days after the tick bite. In most cases, a red rash develops on the wrists and ankles by the third day and often spreads to the entire hand or foot. A blood test is needed to confirm the disease, and early use of antibiotics has a very high rate of cure. The American dog tick is the species thought to carry the agent of RMSF.
Southern Tick-Associated Rash Illness (STARI)
A rash similar to the rash of Lyme disease has been described in humans following bites of the lone star tick. The rash may be accompanied by fatigue, fever, headache, muscle and joint pains.
Ehrlichiosis
Ehrlichiosis is the general name used to describe several bacterial diseases that affect animals and humans. Both the adult and the tiny nymph-stage lone star ticks can carry and transmit ehrlichiosis. Typical symptoms include fever, headache, fatigue, and muscle aches within 1-2 weeks following a tick bite. The lone star tick is the primary vector. Transmission occurs only after the infected ticks have been attached and feeding for at least 24 hours.
Anaplasmosis
Anaplasmosis is caused by a bacterium that is closely related to Ehrlichiosis. Typical symptoms include fever, headache, fatigue, and muscle aches within 1-2 weeks following a tick bite. Anaplasmosis is transmitted only by the deer tick, and most commonly by bites from nymphal stage ticks. Transmission occurs only after the infected ticks have been attached and feeding for at least 24 hours.
Where do ticks live?
Ticks live in or near wooded or grassy areas. Ticks wait for animals from the tips of grass and shrubs. Most ticks climb up on low-lying vegetation and grasses/weeds along trails frequented by their hosts. Here, they cling to the vegetation with their hind legs and wait for a host to pass. As the host brushes against the vegetation, they grab on with their front legs and that is how they get their meal. Ticks can only crawl; they cannot fly or jump.
What do ticks look like?
There are two groups of ticks: “hard” ticks and “soft” ticks. Hard ticks have a hard shield just behind their mouthparts. Hard ticks are shaped like a flat seed when they have not had a blood meal. Soft ticks are shaped like a raisin and do not have the hard shell behind their mouthparts. Soft ticks usually feed on birds or bats. They are rarely encountered unless there is nesting or roosting in an occupied building.
Ticks have four life stages: egg, six-legged larva, eight-legged nymph and adult. After the egg hatches, the tiny larva (seed ticks) feeds on a host. The larva then develops into the larger nymph which feeds on a host and then develops into an adult. Both male and female adults find and feed on a host.
The following are the common ticks you will find in the Mid-Atlantic Region:
American Dog Tick
One of the most frequently encountered ticks is the American dog tick. The larvae and nymphs feed on small warm-blooded animals such as mice and birds. The adult American dog tick will feed on humans and medium to large mammals such as raccoons and dogs.
Unfed males and females are reddish-brown and about 3/16-inch long. Females have a large silver-colored spot behind the head and will become ½-inch long after feeding. Males have fine silver lines on the back and do not get much larger after feeding.
Lone Star Tick
The female is easily distinguished from any other tick by her pronounced white dot or star in the center of her back. The star is actually part of her shield. Lone Star ticks are aggressive and are known to move long distances in pursuit of the host. The larvae, nymphs, and adults will all feed on humans.
The saliva from lone star ticks can be irritating, causing redness and discomfort at the bite site. This does not necessarily indicate an infection.
Deer Tick
This tick is also known as the blacklegged tick and takes 2 years to complete their life cycle. Unfed female deer ticks are easily distinguished from other ticks by the orange-red body surrounding a black center (scutum). Males do not feed.
Brown Dog Tick
They occur predominantly in and around human settlements and infest homes, animal pens, and dog kennels, often causing high levels of infestation both on dogs and in homes. These ticks can spend their entire life cycle indoors. Under optimal conditions, brown dog ticks complete their life cycle in as few as three months.
Adult males and females can be found at all times of the year and can survive for 18 months without feeding. They prefer to feed on dogs but will feed on other mammals, and occasionally humans. Nymphs also can be found at all times of the year and survive for 6 to 9 months without a blood meal.
How can we prevent ticks from getting on us?
Always walk in the center of trails in order to avoid contact with ticks. Since most ticks are on the grasses and other foliage, walking the beaten path is the best option to avoid ticks.
Wearing light colored long sleeved shirts and long pants with the legs tucked into our socks will help prevent ticks from becoming embedded on you. The light colors make is easy to spot the ticks. Having your limbs covered helps prevent ticks from being exposed to your skin, and tucking your pant legs into your socks helps to prevent ticks from crawling up your legs unnoticed.
Don’t forget to wear some sort of insect repellant with 20-30% DEET in it on your skin and a Pyrethrin insecticide on your clothing. Wash this product off your skin after you are done to reduce your exposure to the insecticide. If you are traveling with a friend, make sure you check each other for ticks to reduce exposure.
Check yourself and other family members (especially children) every two to three hours. Ticks seldom attach quickly and hardly ever transmit diseases until they have been attached for at least four hours. If your pets spend time outdoors, make sure to check them for ticks as well.
What to do if you are bitten
Because ticks do not transmit disease until they have been attached to the host for at least several hours, it is important to remove any ticks as soon as they are found. Grasp the tick with tweezers as close to the skin as possible and gently, but firmly, pull it straight out. Avoid any twisting or jerking motion that may break off the mouth parts in the skin. Mouth parts left in the wound may cause an infection. After the tick has been removed, wash hands with soap and water. Make sure you apply a topical antiseptic to the bite site.
If you experience a rash that looks like a bullseye, or a rash anywhere on the body or an unexplained illness accompanied by fever following a tick bite, you should consult your doctor and explain that you were bitten by a tick. Diseases carried by ticks can usually be treated with antibiotics, but the type of antibiotic can vary and individuals should be treated as early in the infection as possible.
