A tick-borne illness that can be severe or fatal among seniors, newborns and people with weakened immune systems is becoming more common in certain parts of the United States, federal health officials warn.
Babesiosis can cause flu or malaria-like symptoms, but young, healthy adults may have no symptoms. The illness is treated with a combination of antibiotics and anti-malaria drugs.
Babesiosis is caused by single-cell parasites called Babesia that are carried by the same kind of ticks that transmit Lyme disease. Rocky Mountain spotted fever is another disease transmitted by ticks.
"Public awareness is critical, because most cases of babesiosis can be prevented by avoiding tick bites," Mark Walderhaug, associate director for risk assessment at the Center for Biologics Evaluation and Research of the U.S. Food and Drug Administration, said in an FDA news release.
He was an author of an FDA study of babesiosis among the elderly that was released last year. It found that seniors in Connecticut, Massachusetts, New York and Rhode Island had the highest rates of babesiosis, and that the disease also appears to be on the rise in Maryland, Virginia and the District of Columbia.
Other hot spots include New Jersey, Minnesota and Wisconsin.
"Indications are that clinical cases reported are only the tip of the iceberg," said Walderhaug. "In some areas, up to 1.5 percent of the population tests positive for Babesia antibodies, meaning they have been infected at some point in the recent past."
Most people who get babesiosis are infected through tick bites, but rare cases of transmission from mother to baby during pregnancy or delivery have been reported. The parasites also can be transmitted through blood transfusions, the FDA noted.
The FDA study of seniors found that whites were more likely than blacks or Hispanics to get babesiosis, and the rates are higher for men than for women. White men had the highest rates of infection.
"We don't know if there are genetic links, but white males, many of whom spend more time outdoors, hunting, hiking, fishing and such, are more likely to be exposed to ticks," Walderhaug said. "People of both sexes and all ages and ethnic groups who go into tick-prone areas should be cautious."