Piggybacking on Lyme disease

As if Lyme disease weren’t enough, nature lovers in New England and the Midwest increasingly have babesiosis to contend with. Transmitted by ticks, the flulike and sometimes deadly disease is now well established in seven US states. One of the problems, Yale researchers have found, is that mice infected with Lyme bacteria may be helping to spread babesiosis.

A team led by epidemiology researcher Maria Diuk-Wasser found that a mouse carrying both Lyme and babesiosis is more likely to pass babesiosis to ticks than is a mouse infected with babesiosis alone. In fieldwork with wild mice, the researchers also found two other factors in the spread of babesiosis to ticks: the degree of tick infestation and the seasonal timing of the ticks’ mouse-blood meals. They then built a mathematical model to predict where babesiosis might head next. (The study appeared in the December 29 issue of PLoS ONE.)

Babesiosis and Lyme are among a handful of infections now known to be transmitted by the blacklegged (or deer) tick, whose range across the country is gradually expanding.