Babesia is parasitic infection that can be transmitted by the deer tick in Lyme disease. It is a protozoa that infects red blood cells and causes malaria like symptoms. Here are some relevant sites:

The Tick Research Laboratory - Human Babesiosis:
http://riaes.cels.uri.edu/resources/...b/babesia.html

Brief general information with a picture of babesia infected blood cells:
http://www.vetmed.ucdavis.edu/VBDP/babesia.htm

Infection with a Babesia-Like Organism in Northern California:
http://content.nejm.org/cgi/content/abstract/332/5/298

Babesia Infections in Switzerland?
http://www.ilads.org/swiss.html

There is also a book by James Schaller, MD titled - "The Diagnosis and Treatment of Babesia"