Role of Deer in the Epizootiology of Babesia Microti in Massachusetts, USA1

The role of deer in the epizootiology of human babesiosis was studied by examining deer collected on Nantucket and Naushon Islands, Massachusetts, USA, for evidence of Babesia microti infection and infestation by the vector tick, Ixodes dammini. All stages of this tick were abundant on deer examined. but no Babesia organisms were found in their blood. There was no evidence of infection found in deer experimentally inoculated with B. microti. These observations suggest that deer are important hosts for all active stages of I. dammini but are not reservoirs for B. microti.