A rare disease spread by ticks has slowly established a foothold in Virginia.
Babesiosis, a parasitic infection similar to malaria, was traditionally limited to the U.S. Northeast and Midwest.
But over the past decade, officials throughout the Mid-Atlantic have noticed an uptick in confirmed cases of the disease. Researchers from Old Dominion University and the Virginia Department of Health recently contributed to a study published in the Journal of Medical Entomology that confirms the regional trend.
“We had all started hearing reports of different cases back in our own jurisdictions,” said Holly Gaff, a biology professor and head of ODU’s Tick Lab. “So we all went back and dug through our data and put it together to be able to string together the story of the significant increase that we were seeing in this Mid-Atlantic area.”
Josh Bernick, a tick-borne disease epidemiologist at VDH, said the health department saw a few isolated cases of babesiosis starting around 2016.
“We’d get a case one year, the next year we’d get zero,” he said. “But what happened is all of a sudden in 2022 it broke the cycle and we saw four cases. Then in 2023 we had seven cases. And that's when we were like, ‘OK, there's something definitely going on.’”
Between 2016 and 2025 Virginia has had a total of 44 confirmed cases of babesiosis, about half of which were contracted within the state, according to VDH. At least two Virginians died from the infection.
The disease is caused by a parasite called Babesia microti — different from many well-known tick-borne diseases, such as Lyme disease or Rocky Mountain spotted fever, which are caused by bacteria.
Gaff said the parasitic infection is more akin to malaria. In both diseases, the parasite enters and infects a person’s red blood cells.
People infected with babesiosis typically either have mostly flu-like symptoms or none at all. But severe cases can lead to life-threatening complications such as anemia, particularly for people with weakened immune systems.
Babesiosis remains relatively rare, with only a few thousand cases reported in the U.S. each year. But national health officials consider it an emerging infectious disease.
Gaff said the southward spread is likely tied to the pattern of Lyme disease, which comes from the same species: the deer tick, or black-legged tick.
Primary vectors for these ticks include white-tailed deer and rodents. As the Southeast has slowed hunting of deer and restored forest habitat, “we basically just create a beautiful environment for ticks to move into, because the ticks' food is there,” Gaff said.
About two decades ago, Lyme disease started sweeping through the Mid-Atlantic, she said. Babesiosis now appears to be repeating the trend.
“Some diseases will rip through an area very quickly, and this is one that's a little slower,” Gaff said. “So I think it's just the timing is right for that wave to follow behind.”
The Eastern Shore is a hotspot for ticks and accounted for the greatest share of babesiosis cases in Virginia thus far.
There is a second tick species that carries the Babesia parasite. Gaff said it does not bite humans, but shares hosts in the environment, which could “amplify the pathogens into the human-biting ones.”
In Hampton Roads, about 90% of ticks are of the lone star species, which does not transmit the pathogens that cause Lyme disease or babesiosis.
Bernick said Virginians shouldn’t panic about the rise in cases, but public health officials should be on the lookout to properly identify the illness.
Because it causes mostly mild symptoms, such as fever, aches and general malaise, it can be easily confused with other diseases, including Lyme. But the parasitic babesiosis won’t respond to antibiotics that target bacterial infections.
Residents who remove a tick should try and keep it so scientists can confirm the pathogen under a microscope, Bernick said.
But “the best way to prevent becoming sick in the first place is to avoid tick bites,” he said.
Here’s how to properly protect against and remove ticks when spending time outdoors, according to VDH:
- Use EPA-registered insect repellent on clothing and skin, ideally containing DEET. Those sensitive to traditional repellents can use more natural options such as oil of lemon eucalyptus. A repellent called permethrin can also be used to treat clothing several days ahead of time and lasts for several months, even after several washes. Make sure the treated clothing is dry before wearing it.
- Tuck your pant legs into socks. Ticks live mainly in forest leaf litter or shaded grassy areas. Tucking pants into socks helps prevent the creatures from climbing up your shoe onto bare skin.
- Check your entire body and pets for ticks after returning indoors. An ideal way to do so is in the shower. They often look like a small, dark mole and can eventually cause surrounding swelling.
- Safely remove the tick, using tweezers to grasp it as close to the skin as possible and pulling straight upwards to avoid breaking its body. Afterward, clean the area with rubbing alcohol or soap and warm water.
- If you feel sick after a tick bite, tell your doctor that you were recently bitten by a tick and where, including the potential species.
- Save your tick for identification. You can send a removed tick to VDH in the mail through the Virginia Tick Survey initiative. Find more details on the department’s website.
