CDC reports tick-borne illness babesiosis on the rise

Local tick specialist estimates that more than 1 in 10 deer ticks carry the disease

A deer tick - Courtesy U.S.D.A.

Cases of babesiosis, a rare tick-borne disease, are on the rise throughout the Northeast, according to a recent study and report from the Centers for Disease Control and Prevention. 

Pronounced ‘ba-bee-zee-oh-ses,” the infection is spread by bites from deer ticks, also known as black-legged ticks. The ticks can transmit microscopic parasite babesia microti, which can cause a parasitic infection of the red blood cells.

Not every deer tick is necessarily carrying the disease, but Patrick Roden-Reynolds, a wildlife and public health biologist with the The Martha’s Vineyard Tick-Borne Illness Reduction Initiative, recommends getting tested after any deer tick bite.

“An important tidbit about babesiosis, transmission can occur within 16 hours after the bite, which is a little bit faster than lyme disease,” Roden-Reynolds said.

Also carried by deer ticks, Lyme is thought to take 24-48 hours for disease transmission to occur. 

“Visit your doctor and they’ll decide if they want to run tests or not,” Roden-Reynolds said. “If you don’t know, it’s better safe than sorry because babesiosis, if it goes untreated, can be fatal.”

Roden-Reynolds estimates that 10-15 percent of the ticks on Martha’s Vineyard are carriers of babesiosis, as compared with up to 40 percent that carry Lyme. “Babesiosis would be the number two most common disease that deer ticks transmit,” Roden-Reynolds said.

According to the CDC report, the first ever case of babesiosis in the United States was identified in 1969 on Nantucket.

The most common symptoms include “fever, muscle and joint pain, and headache. In certain patients, severe complications can occur, including thrombocytopenia, renal failure, and acute respiratory distress syndrome,” the CDC reports. Thrombocytopenia is a condition characterized by abnormally low blood platelet counts.

“Babesiosis can cause illness ranging from asymptomatic or mild to severe; the disease can be fatal, particularly among persons who are immunocompromised or asplenic,” the CDC reports.

While treatable using a combination of prescription antimicrobial medication — including antibiotic and antiparasitic drugs — if left untreated, babesiosis can cause very low blood pressure, liver problems, anemia, kidney failure, heart failure, and death. 

Like other tick-borne illnesses, babesiosis may have made its way to Martha’s Vineyard and other states on the backs of seagulls or swimming deer. This parasite babesia microti has been identified all over the world, in Asia, Australia, Africa, and South America, but most cases are found in North America and Europe. 

Babesia has been endemic, or native, to the state of Massachusetts since the first reported case in 1969, but the number of infections across all endemic US states is on the rise, with more than 1,800 new cases of babesiosis reported every year between 2011 and 2019, as compared to Lyme disease, which the CDC says receives 30,000 new cases reported per year. 

The CDC also reports that the number of U.S. tick-borne disease cases have increased 25 percent by almost 10,000 cases per year, from 40,795 cases reported in 2011 to 50,856 cases reported in 2019. 

The CDC didn’t give a definitive answer as to why cases might be on the rise, but increased testing could be one answer. NPR reports that state programs tracking cases of tick-borne illnesses have said milder winters could also be behind the increasing number of infections. Mild winter temperatures allow ticks to remain active for more months of the year, as ticks become less active in colder temperatures.

“If it’s below 40 degrees you usually won’t see them out,” says Roden-Reynolds. Studies say that ticks actually perish below temperatures of 14 degrees fahrenheit. 

The CDC report emphasizes additional complications of babesia infections for blood banks in endemic states that may impact blood donation, organ transplants, and births. “Transmission can also occur through blood transfusions, transplantation of organs from infected donors, or congenital (mother-to-child) transmission,” the CDC reports. The FDA is recommending blood donation screening where the parasite is endemic. 

“The expansion of babesiosis risk could have implications for the blood supply,” says the CDC report. “Babesia is transmissible via blood transfusion, and persons who acquire babesiosis through contaminated blood have been shown to have significantly worse health outcomes and a higher risk for death than do those who acquire the disease from a tick bite.” 

“Clinicians need to be aware of the signs and symptoms of and risk factors for babesiosis in their practice areas,” says the report.  

Roden-Reynolds recommends practicing tick bite prevention, which includes wearing long sleeves and pants, tucking pants into socks, avoiding tall grass and dense underbrush, and using tick repellant, or wearing clothing treated with a tick repellant spray called permethrin. People can treat their own clothes by buying the spray, pre-treated clothing, or by sending their clothes to certain companies to have them professionally treated.  

Roden-Reynolds recommends the company Insect Shield, which sells the spray, pre-treated clothing, and offers treatment of personal items. He especially recommends it for anyone who works outdoors or spends a significant amount of time in tick habitats.

“Let’s say you have a pair of coveralls that you wear pretty regularly. You send it in to the company and about 2 weeks later they send it back. Professional treatment lasts up to 70 washings,” Reynolds said.  “A piece of [home] treated clothing will last up to 6 weeks or 6 washings, whichever comes first.” 

If you find a tick crawling, do not put it back outside. The CDC recommends disposing of a live tick by tightly wrapping it in tape and then putting it in the trash or flushing it down the toilet. Ticks can also be killed by submerging them in rubbing alcohol.

If you have been bitten by a tick, use a pair of fine tipped tweezers to grasp the tick as close to the skin as possible and slowly and steadily pull it off. After removal, thoroughly clean hands and bite area with rubbing alcohol or soap and water. 

The MV Tick Program will provide surveys of private properties to assess tick populations. According to their webpage, “from mid-May through the end of July Tick Program staff will visit your yard, complete an assessment of potential tick habitat, check the yard for ticks and discuss ways you can reduce the number of ticks and the chance of being bitten.”   You can request a Tick Yard Survey online.


  1. Definitely here, I was bit by one in 2019, unfortunately, also bit by a brown footed, (anaplasmosis) and a lyme tick , between July and November. Yes, 3 ticks in 4 months! All infected. Be careful out there! There are only a couple of doctors here interested in learning treatments.

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