of the infectious agent.
             First, the disease was seasonal, occurring most commonly in the summer and much less so in the middle of the winter. In geographic areas such as Connecticut, these findings suggest that the virus was either a summer virus or an infection carried by and insect or a tick (7:35).
             Second, the disease did not spread from one person in a family to another. Summer viruses were commonly spread from person to person, especially those living in the same household. When a summer virus was eliminated, the focus shifted to the involvement of arthropods (7:37).
             Third, the disease was much more prevalent on one side of the Connecticut River than the other. Since the Connecticut River bisects the state, this became an important factor in finding the cause of the disease. The researchers found a good correlation with the frequency of a certain tick now named Ixodes scapularis. When furthered questioned, the affected people remembered being previous bitten by a tick (2:27).
             At first, the infectious agent producing Lyme disease was thought to have been either a virus, protozoan, fungi, or bacteria. Among the possible agents, bacteria was the highest on the list. European physicians had been treating patients with medicines that were effective against bacteria. However, these findings were not originally accepted in the United States. It was only after some of the patients in Steere's study were successfully treated with antibiotics, which are effective against bacteria, but not against viruses, protozoan, or fungi, that bacteria was determined to be the infectious agent (14:1015).
             The specific bacteria was found by Willy Burgdorfer, an expert on a variety of tick-borne diseases. While working at Montana's Rocky Mountain Laboratories, Burgdorfer received a shipment of ticks from New York. After looking at the contents of the ticks through a microscope, Burgdorfer found a wavy form of a spiro...