The most common tickborne illness in America starts with a bite that many people never notice. Lyme disease is caused by the bacterium Borrelia burgdorferi and is spread through the bite of infected blacklegged ticks, commonly known as deer ticks. Early symptoms often include fever, fatigue, headaches, and the distinctive bull's-eye rash that develops around the bite site. When diagnosed early, Lyme disease is typically treated successfully with antibiotics, making prompt medical attention especially important.
The same tick that spreads Lyme disease can carry another potentially serious infection. Anaplasmosis is a bacterial illness transmitted by blacklegged ticks and usually appears within one to two weeks of a tick bite. Common symptoms include fever, chills, muscle aches, and headaches that often resemble a severe flu. Without treatment, the illness can become serious, but it generally responds well to doxycycline when caught early.
A lone star tick bite can lead to a dangerous infection that doctors don't wait to treat. Ehrlichiosis is caused by bacteria in the Ehrlichia family and is spread primarily by the lone star tick. Symptoms commonly include fever, fatigue, headaches, and occasionally a rash. Because the disease can become severe or even life-threatening, physicians often begin antibiotic treatment immediately rather than waiting for laboratory confirmation.
This tickborne parasite attacks your red blood cells much like malaria. Babesiosis is caused by a microscopic parasite that infects red blood cells and is spread by blacklegged ticks. Many patients develop flu-like symptoms such as fever, chills, and extreme fatigue. While healthy individuals often recover without major complications, older adults and people with weakened immune systems may require medication to prevent severe illness.
One of the deadliest tickborne diseases becomes far more dangerous when treatment is delayed. Rocky Mountain spotted fever is caused by the bacterium Rickettsia rickettsii and is transmitted by dog ticks and wood ticks. The illness often begins with a sudden high fever, severe headache, and a spotted rash that typically starts on the wrists and ankles. Immediate treatment with doxycycline is critical because the disease can become fatal within days if left untreated.
Known as "rabbit fever," this disease is one of the most infectious illnesses on Earth. Tularemia is caused by the bacterium Francisella tularensis and can spread through tick bites, infected animals, or even contaminated dust. Symptoms vary depending on how infection occurs but frequently include fever, swollen lymph nodes, and skin ulcers. Although highly infectious, it can usually be treated successfully with appropriate antibiotics.
This rare virus can spread in as little as fifteen minutes after a tick attaches. Powassan virus is carried by deer ticks, groundhog ticks, and squirrel ticks. Unlike many tickborne diseases that require hours of attachment for transmission, Powassan may spread extremely quickly. Severe infections can cause encephalitis, or swelling of the brain, and some survivors experience long-term neurological complications. There is currently no specific antiviral treatment.
A newly discovered virus is quietly emerging across parts of the United States. First identified in Missouri in 2009, Heartland virus is spread primarily by lone star ticks. Infected individuals often experience fever, fatigue, low platelet counts, and reduced white blood cell counts. Because no specific treatment exists, doctors focus on supportive care while the immune system fights the infection.
A mysterious illness first identified in Kansas continues to puzzle researchers. Named after Bourbon County, Kansas, where it was first discovered in 2014, Bourbon virus causes symptoms including fever, fatigue, rash, nausea, and body aches. Like Heartland virus, there is no targeted treatment available. Although rare, cases have been reported across several Midwestern and Southern states.
This mountain-region illness causes a fever that can disappear and return repeatedly. Colorado tick fever is a viral disease spread by the Rocky Mountain wood tick, primarily at higher elevations in the western United States. Patients commonly experience fever, chills, headaches, body aches, and fatigue. One unusual characteristic is that the fever often returns in multiple waves over several days before finally resolving.
A Lyme-like illness that often lacks Lyme disease's most recognizable symptom. Hard tick relapsing fever is caused by Borrelia miyamotoi, a bacterium spread by the same blacklegged ticks that transmit Lyme disease. Unlike Lyme disease, however, it usually does not produce the classic bull's-eye rash. Patients often develop recurring fevers, fatigue, headaches, and muscle aches, but treatment with doxycycline is typically very effective.
A tick bite you never notice can trigger recurring fevers for weeks. Soft tick relapsing fever is spread by soft-bodied ticks that commonly live in cabins, caves, and rodent-infested structures. These ticks feed quickly, meaning many victims never realize they've been bitten. The disease is known for repeated cycles of high fever that can return multiple times over days or weeks. Fortunately, antibiotics are highly effective against it.
The rash looks exactly like Lyme disease, but scientists still don't know what causes it. Southern Tick-Associated Rash Illness, or STARI, is spread by lone star ticks and produces a rash nearly identical to the classic Lyme disease bull's-eye. Patients may also experience fatigue, fever, headaches, and muscle pain. Despite years of research, scientists have not definitively identified the organism responsible for the illness.
A dark scab at the bite site often gives doctors an important clue. This spotted fever illness is caused by the bacterium Rickettsia parkeri and spread by Gulf Coast ticks. Symptoms include fever, headaches, rash, and a distinctive dark scab known as an eschar where the tick attached. Although it resembles Rocky Mountain spotted fever, it is generally milder and responds well to doxycycline treatment.
A newly recognized disease that researchers are still working to understand. 364D rickettsiosis is caused by Rickettsia philipii and transmitted primarily by Pacific Coast ticks in California. Patients often experience fever, headaches, rash, and an eschar at the bite site. Because it was only identified as a human disease in the early 2000s, scientists continue studying its long-term effects and distribution.
One tick bite can make eating a hamburger dangerous for the rest of your life. Alpha-gal syndrome is an unusual allergic condition triggered by lone star tick bites. The bite can sensitize the immune system to a sugar molecule called alpha-gal, which is found in mammalian meat products. Afterward, consuming foods such as beef, pork, or lamb may trigger delayed allergic reactions that can range from mild to life-threatening.
This serious viral disease is a major concern in parts of Europe and Asia. Tick-borne encephalitis, commonly called TBE, is caused by a flavivirus spread by Ixodes ticks. Early symptoms often resemble the flu, but severe cases can progress to inflammation of the brain and lasting neurological damage. A vaccine is available for travelers visiting high-risk regions where the disease is common.
Sometimes the danger isn't an infection — it's a toxin hidden in the tick's saliva. Tick paralysis occurs when certain feeding ticks release a neurotoxin that interferes with the nervous system. Victims may develop weakness that gradually progresses upward through the body and can resemble serious neurological disorders. The remarkable aspect of this condition is that symptoms usually reverse quickly once the tick is found and removed.
