Anaplasmosis: Another tick-borne illness, another reason to protect yourself against ticks

Anaplasmosis is a tick-borne disease that can cause serious illness. In the U.S., between 5,000 and 6,000 cases of anaplasmosis are reported each year. If you develop anaplasmosis from a tick bite, taking the antibiotic doxycycline as early as possible can help prevent serious illness.

What is anaplasmosis?

Anaplasmosis is a bacterial infection caused by the bite of a tick infected with the bacteria Anaplasma phagocytophilum. If left untreated, the infection can cause serious illness.

How is anaplasmosis transmitted?

Anaplasmosis is most commonly transmitted through the bite of an infected tick. When the tick bites a person, the bacteria can enter the person's bloodstream and attack their red blood cells.

Many kinds of ticks are found in different parts of the United States. The ticks known to cause anaplasmosis are the blacklegged tick and the Western blacklegged tick. The tick must be infected with A. phagocytophilum in order to spread the disease.

In the U.S., anaplasmosis is most common in the Northeastern and upper Midwestern states. People who live near or spend time in places where ticks are common are at higher risk for anaplasmosis.

In rare cases, anaplasmosis can be transmitted through blood transfusion.

Symptoms and complications of anaplasmosis

Anaplasmosis symptoms typically begin within one to two weeks after the bite of an infected tick. But because tick bites are usually painless, many people are unaware that they have been bitten.

Early symptoms of anaplasmosis include fever and chills, headache and muscle aches, and nausea, vomiting, diarrhea, and loss of appetite. The early symptoms of anaplasmosis mimic those of other tick-borne diseases as well as common viruses.

Later complications of anaplasmosis are more serious and include respiratory failure, uncontrolled bleeding, brain inflammation, and organ failure.

People ages 65 and older and people with weakened immune systems have a higher risk of serious illness from anaplasmosis.

Diagnosing anaplasmosis

Your doctor can diagnose anaplasmosis by reviewing your symptoms and medical history (including whether you have spent time outdoors in an area where blacklegged ticks or Western blacklegged ticks are common) and ordering certain blood tests. Because the test results may take some time to come back, your doctor may prescribe treatment before the results come in, if anaplasmosis is likely.

Treatment for anaplasmosis

Anaplasmosis is treated with the antibiotic doxycycline. Doxycycline is most effective at preventing severe complications if it is started soon after symptoms appear. Delaying treatment increases the risk of serious illness.

Doxycycline is usually taken for at least 10 days to treat anaplasmosis.

People who cannot take doxycycline can be treated with a different antibiotic, rifampin.

Protecting yourself against tick bites: The best way to prevent tick-borne illnesses

There is no vaccine to prevent anaplasmosis. The best way to avoid anaplasmosis and other tick-borne diseases is to prevent tick bites.

Steps you can take to prevent tick bites include:

• Wear light-colored clothing to make it easier to see ticks.
• Tuck your pant legs into your socks and your shirt into your pants.
• Use an insect repellent containing DEET or picaridin.
• Treat your clothing and shoes with products containing permethrin, an EPA-registered insecticide that kills ticks on contact.
• Avoid moist, shady areas like woods, tall grass, shrubs, brush, and leaf piles — all places ticks like to live.
• Stay in the middle of walking paths.
• Check yourself, your children, and your pets for ticks after being outdoors.

If you do get a tick bite, remove the tick as soon as possible to help prevent disease transmission. Typically, a tick must stay attached for 12 to 24 hours in order to transmit anaplasmosis. However, ticks can transmit other infections more quickly. To remove a tick, you can use tweezers or a tick removal device sold at many pharmacies.

In addition to anaplasmosis, other diseases transmitted by ticks include Lyme disease, Rocky Mountain spotted fever, ehrlichiosis, babesiosis, tularemia, Colorado tick fever, and tick-borne relapsing fever. Depending on your location and the nature and severity of your symptoms, it may be necessary to test and treat for more than one infection (such as simultaneous anaplamosis and Lyme disease).