Ticks transmit over 20 pathogens that can make humans, pets or wildlife sick from just one single bite. Tick-borne illnesses are caused by infection with a variety of pathogens, including rickettsia and other types of bacteria, viruses, and protozoa. Because individual ticks can harbor more than one disease-causing agent, patients can be infected with more than one pathogen at the same time, making it difficult to diagnosis. Many tick-borne diseases initially start with mild to severe flu-like symptoms that may include fever, headache, sweats, chills, fatigue, muscle/joint pain, nausea, diarrhea, vomiting and rashes. Because symptoms can be vague, diagnosis may be difficult. Becoming familiar with ticks and the diseases they may transmit will help in the early recognition of illness. The earlier diseases are diagnosed and treated, the better the outcome.
Tick species that transmit anaplasmosis: Deer tick (Ixodes scapularis), western black-legged tick (Ixodes pacificus)
What is Anaplasmosis?
Human granulocytic anaplasmosis (HGA), previously known as human granulocytic ehrlichiosis (HGE), is a tick-associated disease caused by a species of bacteria called Anaplasma phagocytophilum. HGA is transmitted to humans by the bite of the deer tick and western black-legged tick. People exposed to the disease agent often have difficulty being diagnosed because of the non-specific nature of the symptoms. Most experience headaches, fever, chills, myalgia, and malaise that can be confused with other infectious and non-infectious diseases. Rashes are rarely reported by people exposed to HGA.
Where is Anaplasmosis Prevalent?
HGA is transmitted to humans by the deer tick and western black-legged tick. Deer ticks infected with A. phagocytophilum are found in the New England and North Central United States while black-legged ticks infected with A. phagocytophilum are found in northern California. States reporting the highest incidence of HGA in 2001-2002 were Rhode Island, Minnesota, Connecticut, New York, and Maryland. Most cases occur in the spring and summer months. During this time, nymphal deer ticks are most likely to come into contact with humans in New England and North Central United States. Adult deer ticks may transmit the infection in the fall. The main animal reservoir for A. phagocytophilum in Eastern regions is the white-footed mouse
Clinical manifestations of HGA can range from mild to life-threatening depending on the patient’s age and general health. Onset of anaplasmosis generally begins within a week of a tick bite, and often includes fever, severe headaches, malaise, muscle pains, and chills. Other symptoms may include confusion, hemorrhages, and renal failure.
An initial diagnosis is based on the patient’s symptoms and laboratory tests. Routine laboratory results include a low white blood cell count, low platelet count, and elevated levels of specific liver enzymes. Blood smears may be used to look for characteristic morulae (microcolonies) of A. phagocytophilium in affected blood cells. However, a confirmed diagnosis can only be made using the PCR (Polymerase Chain Reaction) or by immunostaining methods.
BabesiosisBabesiosis is caused by microscopic parasites that infect red blood cells and are spread by certain ticks. In the United States, tickborne transmission is most common in particular regions and seasons: it mainly occurs in parts of the Northeast and upper Midwest and usually peaks during the warm months.
Although many people who are infected with Babesia do not have symptoms, for those who do effective treatment is available. Babesiosis is preventable, if simple steps are taken to reduce exposure to ticks.
Borrelia miyamotoi Disease
What is Borrelia miyamotoi?
Borrelia miyamotoi is a species of spiral-shaped bacteria that is closely related to the bacteria that cause tick-borne relapsing fever (TBRF). It is more distantly related to the bacteria that cause Lyme disease. First identified in 1995 in ticks from Japan, B. miyamotoi has since been detected in two species of North American ticks, the black-legged or “deer” tick (Ixodes scapularis) and the western black-legged tick (Ixodes pacificus). These ticks are already known to transmit several diseases, including Lyme disease, anaplasmosis, and babesiosis.
What type of illness does B. miyamotoi cause?
In a 2015 case series, patients with this infection were most likely to have fever, chills, and headache. Other common symptoms included body and joint pain and fatigue. Unlike Lyme disease, rash was uncommon, presenting in only 4 out of 51 patients.
Colorado Tick Fever
What is Colorado tick fever?
Colorado tick fever (CTF) is a rare disease that is caused by the CTF virus. CTF virus is spread to people through bites of infected ticks. The most common symptoms of CTF are fever, chills, headache, body aches, and feeling tired.
How do people get infected with Colorado tick fever virus?
CTF virus is transmitted by the bite of an infected Rocky Mountain wood tick (Dermacentor andersoni). The virus is not spread from person to person, except in rare instances by blood transfusion.
Ehrlichiosis is the general name used to describe diseases caused by the bacteria Ehrlichia chaffeensis, E. ewingii, or E. muris eauclairensis in the United States. These bacteria are spread to people primarily through the bite of infected ticks including the lone star tick (Amblyomma americanum) and the blacklegged tick (Ixodes scapularis).
People with ehrlichiosis will often have fever, chills, headache, muscle aches, and sometimes upset stomach.
Signs and symptoms of ehrlichiosis typically begin within 1-2 weeks after the bite of an infected tick.
Tick bites are usually painless, and many people do not remember being bitten.
See your healthcare provider if you become ill after being bitten by a tick or spending time in grassy, brushy, wooded areas.
Early signs and symptoms (the first 5 days of illness) are usually mild or moderate and may include:
Nausea, vomiting, diarrhea, loss of appetite
Rash (more common in children)
Up to 1 in 3 people with ehrlichiosis report a rash; rash is more common in people with E. chaffeensis ehrlichiosis and generally occurs more often in children than adults. Rash usually develops 5 days after fever begins. If a person develops a rash, it can look like red splotches or pinpoint dots.
If antibiotic treatment is delayed, ehrlichiosis can sometimes cause severe illness. Early treatment can reduce your risk of developing severe illness.
Signs and symptoms of severe (late stage) illness can include:
Damage to the brain or nervous system (e.g. inflammation of the brain and surrounding tissue (called meningoencephalitis))
Heartland and Bourbon Virus DiseasesHeartland virus
Heartland virus is an RNA virus in the genus Phlebovirus, family Phenuiviridae believed to be transmitted by the Lone Star tick (Amblyomma americanum). First discovered as a cause of human illness in 2009 in Missouri, more than 35 cases of Heartland virus disease have been reported from states in the midwestern and southern United States to date. Most people diagnosed with the disease became sick during May through September. Bourbon virus is an RNA virus in the genus Thogotovirus, family Orthomyxoviridae that was recently discovered in Bourbon County, Kansas. Only a few cases of Bourbon virus disease have been identified in the United States, and the geographic distribution appears to be similar to that of Heartland virus.
Although it is not yet known how people become infected with Bourbon virus, most patients reported exposure to ticks before becoming ill and the virus has been identified in Lone Star ticks. Symptoms for both diseases have included fever, fatigue, anorexia, nausea, and diarrhea. Patients with Bourbon virus disease might also present with a diffuse, maculopapular rash. Both viruses have been found to cause leukopenia, thrombocytopenia, and elevated liver transaminases.
Who should be tested for Heartland and Bourbon virus disease?
Testing for Heartland or Bourbon virus should be considered for patients with an acute febrile illness within the past 3 months AND at least one epidemiologic criterion AND at least one clinical criterion. Epidemiologic criteria 1) Known tick bite, finding tick on body, or potential exposure to ticks through outdoor activities in the 3 weeks prior to illness onset during spring through fall (e.g., April–October); OR 2) Resides in or recently traveled to an area with previous evidence of Heartland or Bourbon virus Clinical criteria
1) Leukopenia (white blood cells <4,500 cells/µL) or thrombocytopenia (platelets <150,000 cells/mL) not explained by another known condition; OR
2) Suspected tickborne disease (e.g., ehrlichiosis, Rocky Mountain spotted fever) with no clinical response to appropriate treatment.
What is Lyme Disease?
Lyme disease (LD) is an infection caused by Borrelia burgdorferi, a type of bacterium called a spirochete (pronounced spy-ro-keet) that is carried by deer ticks. An infected tick can transmit the spirochete to the humans and animals it bites. Untreated, the bacterium travels through the bloodstream, establishes itself in various body tissues, and can cause a number of symptoms, some of which are severe. Often, an erythema migrans (EM) rash appears within 7-14 days at the site of a tick bite.
LD manifests itself as a multisystem inflammatory disease that affects the skin in its early, localized stage, and spreads to the joints, nervous system and, to a lesser extent, other organ systems in its later, disseminated stages. If diagnosed and treated early with antibiotics, LD is almost always readily cured. Generally, LD in its later stages can also be treated effectively, but because the rate of disease progression and individual response to treatment varies from one patient to the next, some patients may have symptoms that linger for months or even years following treatment. In rare instances, LD causes permanent damage.
Although LD is now the most common arthropod-borne illness in the U.S. (more than 150,000 cases have been reported to the Centers for Disease Control and Prevention [CDC] since 1982), its diagnosis and treatment can be challenging for clinicians due to its diverse manifestations and the limitations of currently available serological (blood) tests.
Rocky Mountain Spotted Fever
Rocky Mountain spotted fever is a bacterial infection transmitted by a tick. Without prompt treatment, Rocky Mountain spotted fever can cause serious damage to internal organs, such as your kidneys and heart.
Although it was first identified in the Rocky Mountains, Rocky Mountain spotted fever is most commonly found in the southeastern part of the United States. It also occurs in parts of Canada, Mexico, Central America and South America.
Early signs and symptoms of Rocky Mountain spotted fever include a severe headache and high fever. A few days later, a rash usually appears on the wrists and ankles. Rocky Mountain spotted fever responds well to prompt treatment with antibiotics.
Although many people become ill within the first week after infection, signs and symptoms may not appear for up to 14 days. Initial signs and symptoms of Rocky Mountain spotted fever often are nonspecific and can mimic those of other illnesses:
Severe headache Muscle aches
Nausea and vomiting
Confusion or other neurological changes
Rash is distinctive
The red, nonitchy rash associated with Rocky Mountain spotted fever typically appears three to five days after the initial signs and symptoms begin. The rash usually makes its first appearance on your wrists and ankles, and can spread in both directions — down into the palms of your hands and the soles of your feet, and up your arms and legs to your torso.
Some people who are infected with Rocky Mountain spotted fever don’t ever develop a rash, which makes diagnosis much more difficult.
Rocky Mountain spotted fever damages the lining of your smallest blood vessels, causing the vessels to leak or form clots. This may cause:
Inflammation of the brain (encephalitis). In addition to severe headaches, Rocky Mountain spotted fever can cause inflammation of the brain, which can cause confusion, seizures and delirium.
Inflammation of the heart or lungs. Rocky Mountain spotted fever can cause inflammation in areas of the heart and lungs. This can lead to heart failure or lung failure in severe cases.
Kidney failure. Your kidneys filter waste from your blood, and the blood vessels within the kidneys are very small and fragile. Damage to these vessels can eventually result in kidney failure.
Serious infection, possibly amputation. Some of your smallest blood vessels are in your fingers and toes. If these vessels don’t work properly, the tissue at your farthest extremities may develop gangrene and die. Amputation would then be necessary.
Death. Untreated, Rocky Mountain spotted fever has, historically, had a death rate as high as 80 percent.