Babesiosis, a tick-borne disease that can be fatal in rare cases, is becoming more prevalent in the Northeast, the Centers for Disease Control and Prevention said in a report released on Thursday.
The findings show that eight out of 10 states that reported cases of babesiosis from 2011 to 2019 saw their numbers increase, while just two – Minnesota and Wisconsin – saw a decline.
What’s more, babesiosis is now considered endemic in three new states: Maine, New Hampshire, and Vermont. Previously, the disease was considered endemic only in Connecticut, Massachusetts, Minnesota, New Jersey, New York, Rhode Island, and Wisconsin.
“Nine years of data show [an] Megan Swanson, an epidemiologist in the CDC’s Division of Parasitic Diseases and Malaria who co-authored the report, noted an increase in the tick-borne disease in parts of the U.S. where few cases were previously observed.
Symptoms of babesiosis include fever, chills, sweating, headache, body aches, nausea, fatigue, or muscle and joint pain. The disease has an overall death rate of about 1% to 2%, according to Dr. Peter Krause, a senior research scientist at the Yale School of Public Health who was not involved in the CDC study.
Up to 20% of adult cases and 50% of pediatric cases are asymptomatic. Older or immunocompromised people are most vulnerable to serious consequences such as low blood platelet count, kidney failure or acute respiratory distress syndrome, in which fluid builds up in the lungs.
The report highlights “an unfortunate milestone in the emergence of babesiosis in the United States,” Krause said. “More cases means more disease, and indeed, some people die.”
Babesiosis can be more serious than Lyme disease.
Humans acquire babesiosis largely from deer ticks, whose bites can lead to infection. babesia Parasites that infect red blood cells.
Most transmission occurs from late May to early September. The researchers believe that as climate change increases humidity over long periods of time, it creates a more hospitable environment for ticks.
“Ticks survive the winter better, and so the next spring, you have more ticks biting more people,” said Edouard Vannier, an assistant professor who studies babesiosis at Tufts Medical Center in Boston. ,
New data shows that from 2011 to 2019, the number of cases of babesiosis increased more than 17-fold in Vermont and 34-fold in Maine.
Babesiosis can sometimes be confused with Lyme disease, another tick-borne illness that also causes fever and muscle aches. While Lyme disease has a defining feature — a rash at the site of the tick bite — Krause said there isn’t a clear babesiosis symptom. It is usually diagnosed by a blood test.
“Sometimes the patient just feels tired and not quite right, maybe a low-grade temperature for a week or two, and then all of a sudden they get worse,” Cross said. “That’s not usually the case with Lyme—you get it and then, bingo, you have the rash and so on.”
Babesiosis tends to be more severe than Lyme disease, although Lyme is far more common. The CDC records about 30,000 cases of Lyme disease each year, while a total of about 16,500 cases of babesiosis were reported from 2011 to 2019.
Vannier said that people can have both diseases simultaneously. They estimated that up to half of people with babesiosis also have Lyme disease.
increase in tick-borne diseases
Scientists identified the first human case of babesiosis in the US in 1969. Its increasing prevalence coincides with an overall increase in tick-borne disease, which increased by 25% from 2011 to 2019. From 1999 to 2019, confirmed cases of Lyme disease rose by 44%.
Researchers attribute the trend to a few factors. For one, the deer population has expanded, providing more opportunities for ticks to feed and breed. People are also increasingly traveling and building homes in wild areas.
On top of that, rising global temperatures have resulted in longer summers and shorter winters, and ticks thrive in warm, humid climates.
Krause also noted that older people have come to represent a sizable portion of the population and that they are more susceptible to severe babesiosis and therefore more likely to receive an official diagnosis.
“It is the more severe cases that come to the hospital that are reported,” he said.
The CDC report recommends that people who spend time outdoors in states where babesiosis is endemic wear long pants, use tick repellent and avoid underbrush and tall grass.
Babesiosis is most prevalent compared to the CDC count, the researchers said, taking into account asymptomatic infections and noting that not all physicians refer cases to state health departments and not all states report cases to the CDC.
“Babesia is a much more frequent problem than the general public recognizes and can be fatal — in up to 20% — in people who have HIV/AIDS or have advanced cancer with chemotherapy or who have spleen insufficiency,” Kraus said. Krause said.