Ticks have the potential to carry bacteria, parasites, and viruses that cause disease. These diseases can cause severe harm to both domestic animals and wildlife as well as people and can be fatal if not diagnosed and treated quickly. Humans and animals can become infected through the bite of an infected tick.
There have been no reported human cases of tickborne disease acquired from tick bites that occurred in Alaska. All human cases of tickborne diseases in Alaska have been people that were likely infected while traveling outside of the state and developed symptoms after returning home. Tularemia is a bacterial disease that is present in the state, and has caused disease in domestic animals, wildlife (particularly hares and muskrats), and humans in Alaska. Although a bite from an infected tick is one way to acquire the bacteria, most cases of tularemia in domestic animals and humans in Alaska have been a result of handling infected wildlife, not from a tick bite.
In most cases, a tick needs to be attached to a host for several hours to pass on bacteria, parasites, or viruses in its saliva. Many of the most common tickborne diseases can be treated with antibiotics, if diagnosed quickly. If you or your pet has been bitten by a tick and begin to show signs of these tickborne disease symptoms, contact your local healthcare provider or veterinarian.
Exposure to Ticks When Traveling Outside of Alaska
There has only been evidence of local transmission or tickborne disease activity for a few of the following tickborne diseases in Alaska. However, these diseases are common in many other parts of the United States. If you are traveling outside of the state, check to see if your destination is a tick-affected area. Consider using tick repellent on yourself and talk with your veterinarian about using tick prevention on your pets to prevent tick bites.
- Tickborne Diseases of the United States. Maps from the CDC that show the general distribution of human-biting ticks in the contiguous United States.
- Tickborne Diseases Abroad. A list from the CDC of known pathogens spread by ticks outside of the United States.
Common Tickborne Diseases in the United States
- Anaplasmosis is a bacterial infection spread by bites from infected black-legged ticks (Ixodes scapularis or Ixodes pacificus), the same ticks that can transmit the bacteria that causes Lyme disease. Early symptoms in humans include fever, chills, severe headaches, muscle aches, and nausea, vomiting, or loss of appetite. If treatment is delayed, anaplasmosis can cause severe illness including respiratory or organ failure, bleeding problems, or death. In pets, symptoms can include fever, lethargy, lameness, joint pain, and lack of appetite.
- Babesiosis is a parasitic infection that can cause hemolytic anemia through the destruction of red blood cells. It is most often transmitted to humans and animals through a bite from an infected black-legged tick (Ixodes scapularis). Most people infected with Babesia microti feel fine and do not have any symptoms. Some people develop nonspecific flu-like symptoms such as fever, chills, sweating, body aches, loss of appetite, nausea, or fatigue. Severe infections can cause jaundice (yellowing of the skin) and dark urine.
- Ehrlichiosis is the general name for diseases caused by several different bacteria (Ehrlichia spp.) and is spread by bites from infected lone star ticks (Amblyomma americanum) and black-legged ticks (Ixodes scapularis). People with ehrlichiosis often experience fever, chills, headache, muscle ache, nausea, confusion, or rash (usually in children). The Ehrlichia spp. that most commonly infects dogs is transmitted by the brown dog tick (Rhipicephalus sanguineus). Early symptoms in pets can include fever, swollen lymph nodes, difficulty breathing, and bleeding disorders. If left untreated, the disease can progress, causing anemia, eye problems, swollen limbs, and neurological issues.
- Lyme Disease is the most common vector-borne disease in the United States. Although there have been no reported human cases of Lyme Disease acquired in Alaska, it is important that Alaskans are aware of the signs of infection if traveling outside of the state. Lyme disease is caused by a bacterium transmitted by the black-legged tick (Ixodes scapularis or Ixodes pacificus). Typical early symptoms include fever, headache, fatigue, and a characteristic skin rash where the tick has fed that often expands to look like a “bull’s-eye.” Many days after infection, symptoms can expand to severe headaches and neck stiffness, joint pain and swelling, or facial palsy. Symptoms in pets can include fever, loss of appetite, joint swelling, stiffness and soreness.
- Rocky Mountain Spotted Fever (RMSF) is a bacterial infection spread by bites from infected American dog ticks (Dermacentor variabilis), Rocky Mountain wood ticks (Dermacentor andersoni), or brown dog ticks (Rhipicephalus sanguineus). Early signs and symptoms in humans are non-specific and can include fever, headache, rash, nausea, stomach pain, and muscle aches. The disease can progress rapidly and become fatal if not treated immediately. Early signs in pets can include fever, loss of appetite, and swollen face or extremities.
- Tularemia is caused by a highly-infectious bacterium (Francisella tularensis) that can enter the body through the skin, eyes, mouth, or lungs. The disease is often associated with rabbits, hares, and rodents, but humans and domestic animals can also become infected. Tularemia can be transmitted to humans through bites from infected American dog ticks (Dermacentor variabilis), Rocky Mountain wood ticks (Dermacentor andersoni), or the lone star tick (Amblyomma americanum). Humans can also be infected through bites from deer flies or from handling infected animal tissue (e.g. when hunting or skinning infected rabbits or handling a sick pet). Symptoms of tularemia can include high fever, a skin ulcer where the tick fed, lethargy, and swollen lymph nodes.
Additional Resources for Healthcare Providers and Veterinarians
- The CDC Tickborne Diseases of the US: A Reference Manual for Health Care Providers provides a reference to aid in diagnosis and treatment of tickborne diseases.
- Lyme Disease information for Healthcare Providers from the CDC provides information on diagnosis, treatment, and testing for Lyme disease.
- Tick-borne Disease: Prevalence, Prevention, and Treatment from the American Kennel Club Canine Health Foundation provides maps of cases of common tickborne diseases in dogs in the United States and additional pet-specific symptoms for these diseases.