Tick-borne diseases or tickborne diseases are becoming increasingly common due to climate change and suburbanization. Tick-borne diseases are caused by many pathogens including bacteria and viruses. The symptoms of these diseases range from mild to severe.
Definition & Facts
Some of the most common tick-borne diseases in the U.S include Rocky Mountain spotted fever, anaplasmosis, ehrlichiosis, tularemia, Lyme disease, babesiosis, and Southern tick-associated rash illness (STARI) among others.
Rocky Mountain spotted fever was first identified in 1896 and is transmitted by a cayenne tick. Lyme disease was first identified in Connecticut in the 1970s and has since spread to every state in the U.S. except Hawaii. Southern tick-associated rash illness (STARI), is one of the newest tickborne diseases to be identified in the U.S. The symptoms of this disease resemble those of Lyme disease, another tickborne disease. However, STARI is transmitted by the lone star tick and Lyme disease by the deer tick.
Symptoms & Complaints
Patients with Lyme disease often experience joint pains. Patients with Rocky Mountain spotted fever, Lyme disease, and STARI may experience rashes within 3 to 30 days after incurring a bite followed by high grade fever. Such rashes are often not painful and usually begin at the site of the tick bite.
Symptoms of tularemia often manifest in the form of a skin ulcer at the site of the tick bite as well as swelling of the lymph glands around the armpit or groin. More than half of the people afflicted with ehrlichiosis may develop a rash after the onset of fever.
The symptoms of tickborne diseases are often similar with most patients either developing a rash or experiencing fever or both. However, doctors and health care providers can determine the specific tickborne disease that patients are afflicted with through clinical tests.
Tickborne disease may be caused by a wide range of pathogens. Anaplasmosis is often caused by the backlegged tick often found in the northeastern and upper midwestern U.S and the western backlegged tick, which is more prevalent along the Pacific Coast. Babesiosis is a tickborne disease caused by the parasite, Babesia microti transmitted by the backlegged tick often found in the Northeast and Upper Midwest.
Lyme disease is caused by the Borrelia burgdorferi parasite often transmitted by the backlegged ticks. Lyme disease is prevalent throughout North America. South Central and Eastern U.S. are home to the lone star tick, which causes ehrlichiosis. This tick is also believed to transmit the Heartland virus infection, another tickborne disease that was first described in 2012 and has been found in Missouri and Tennessee among other states.
Rocky Mountain spotted fever is transmitted by the wood tick in the Rocky Mountain states, the dog tick which is located east of the Rockies and in some Pacific Coast areas, and the cayenne tick which is widespread in Central and South America.
People in the South Eastern and Eastern U.S. are more vulnerable to STARI transmitted by the lone star tick. The dog tick, the wood tick, and the lone star tick are associated with tularemia which is prevalent throughout the United States. 364D rickettsiosis is a tickborne disease found mostly in California and transmitted by the Pacific Coast tick.
Diagnosis & Tests
If a person experiences the symptoms listed above within a few weeks, his or her health care provider should evaluate three factors: the geographic region in which the individual was bitten, the area of the body where the individual was bitten, and the results of diagnostic tests.
Confirmation of any tickborne disease is based on laboratory testing. However, treatment should not be delayed for patients who exhibit the symptoms of tickborne diseases. General laboratory findings may include antibodies to the disease within the first seven to ten days of infection, and mild anemia. It is important for laboratory technicians to consider the possibility of co-infection when testing for tickborne diseases.
When considering the diagnosis of babesiosis, doctors will review blood smears, and multiple smears may be required to effectively diagnose the disease. In some cases, it may be difficult to differentiate between babesia and malaria parasites. Although serologic testing is one of the most common diagnostic measures for tickborne diseases, it does not effectively distinguish between active and past infections.
Treatment & Therapy
Doxycycline is one of the most common treatments for anaplasmosis, Rocky Mountain spotted fever, and ehrlichiosis. Patients exhibiting the symptoms of these tickborne diseases should begin treatment immediately. Delay in treatment may result in severe illness and in some cases, even death. The dosage is determined by the patient’s age, underlying health complications, allergies, medical history, and pregnancy status.
Doctors should find out if their patients are allergic to doxycycline before administering the medication. Treatment should continue for a minimum of three days after fever subsides or until the patient’s condition improves. In general, patients should be under treatment for five to seven days. Treatment may be administered orally or through intravenously.
Prevention & Prophylaxis
One should consider walking in the center of trails when outdoors and applying a tick repellant on the skin when going outdoors to areas with large tick populations. One should apply the product on one's child as well while avoiding the mouth, hands, and eyes. One can use laundry products that contain tick repellant like DEET and bathe immediately after coming indoors from tick prone areas.
In addition, one should check one's child for ticks under the arms, behind the knees, between the legs, in the hair, and around the waist. One should examine one's pet frequently for ticks and wash them regularly to rid them of ticks.