Babesiosis is a rare, serious, and sometimes fatal disease spread by the northern deer tick. Ticks can carry a parasite called Babesia microti that attacks the red blood cells of many animals, including man.
Incidence; Causes and Development
As at the time of writing (2002), approximately 200 cases of babesiosis have been reported in the U.S. since the first human case was recognized on Nantucket Island (off the coast of Massachusetts) in 1968.
Babesiosis is a malaria-like illness caused by a protozoan parasite
in the U.S.; other members of the Babesia
genus in Europe) that invades red blood cells
, and is primarily transmitted by the deer tick Ixodes scapularis
and possibly other related Ixodid ticks.
In the US, the deer (black-legged) tick in the Northeast and upper Midwest, and the Western black-legged tick on the Pacific coast are the primary carriers. A majority of reported cases occur during the summer months along the immediate coast and off-shore islands of the Northeast.
Signs and Symptoms
The symptoms of babesiosis normally begin about a week after a tick bite with a gradual onset of malaise
. This is followed several days later by high fever, chills, drenching sweats, muscle pain, joint pain and headaches. As with malaria, these symptoms can continue over a protracted period (several days to several months) or can abate, then recur. Sometimes, a person can be infected with the parasite
but not show any symptoms. In some cases it may take from 1 to 12 months for first symptoms to appear after infection with the parasite.
Treatment and Prevention
There is no specific treatment for babesiosis. However, some medications used in the treatment of malaria have also been useful in the treatment of babesiosis.
While many in the U.S. who are exposed to the parasite
do suffer severe symptoms, such cases often are self-limiting and are eventually resolved with treatment; fatalities generally are limited to elderly patients with compromised immune systems.