Babesiosis: Backyard Killer Mimics Malaria and Is on Rise

Study shows tick-borne parasite on the rise in Northeast and Midwest.

ByABC News
June 21, 2011, 11:00 AM

June 22, 2011— -- Babesiosis, a potentially deadly tick-borne illness that mimics malaria, is on the rise in the suburbs north of New York City, according to a paper published in the May issue of the Emerging Infection Disease Journal.

The disease has also spiked in coastal Rhode Island,Massachusetts, Connecticut and Long Island. At least 1,000 cases have been reported, mostly in the Northeast and the upper Midwest, and for those who are immune-compromised, it can be fatal.

And it's not a new malady, according to Dr. Gary Wormser, chief of infectious diseases at New York Medical College and co-author of the paper.

"One of the earliest reports of this condition is in the Bible and the Plagues of Ten that were imposed on the evil pharaoh of Egypt," he said.

Six cases first appeared in the Lower Hudson Valley in 2001 and by 2008, there were 119 cases, according to the paper, a 20-fold increase.

Most people weather the disease with virtually no symptoms or after effects -- which is precisely why public health officials are worried.

Babesiosis can go undetected in the blood supply -- putting those who are sickest at risk -- and there is no widely used screening test.

Of those who are hospitalized for babesiosis, 1 in 20 dies, according to Wormser. "It's a lot like malaria at its worst."

Symptoms include a high fever, as well as a powerful headache.

"It's variable," he said. "Some people get over it spontaneously and other people get really sick," he said. "At times it's really life-threatening."

The disease is caused by the parasite babesea microti, which invades and destroys the body's red blood cells, according to the Centers for Disease Control and Prevention (CDC).

An estimated 1,000 cases are reported each year,but experts say many more go undiagnosed.

The parasite is relatively new to the Lower Hudson Valley, where Lyme disease has been much more prevalent, according to Wormser. Those cases that were seen, were "imported" from Long Island and Nantucket.

"How it got here is a mystery," he said.

Those with HIV/AIDS, cancer patients undergoing chemotherapy and the elderly are also at risk for the more virulent form of babesiosis. People who have had their spleen removed because trauma or cancer, are also more susceptible.

Experts speculate that, like Lyme disease, babesiosis has spiked because of the surge in the deer population in residential areas.

Because both diseases are carried by the deer tick, some get Lyme disease and babesiosis simultaneously, which can make a correct diagnosis even more difficult.

Those who do experience symptoms report a mild to moderate flu-like illness that can last just days or upto six months.

Those who donate blood tend to be robust and without symptoms, and can therefore pass transmit the disease.

Babesiosis is the most frequently reported infection transmitted through blood transfusions and has caused at least 12 deaths nationwide in the last decade. There were six deaths in New York City alone in 2009.

Currently the only way to screen is to use a questionnaire and ask blood donors if they are infected.

Rhode Island, which has seen the tick-borne disease since 1999, is the first state to try an experimental test after several infants developed babesiosis following blood transfusions.