“…Studies dating back at least to the 1940s indicate that ambient temperature profoundly alters the course of infection in diverse rodent models. In models of bacterial ( Salmonella typhimurium , Staphylococcus aureus , Klebsiella pneumonia , and Rickettsia typhi ), viral (influenza virus, herpes simplex virus, and rabies virus), and protozoal ( Trypanosoma cruzi ) infection, ambient temperature directly correlates with host responsiveness—lower temperatures leading to impaired immune responses (Moragues and Pinkerton, 1944; Miraglia and Berry, 1962; Previte and Berry, 1962; Underwood et al, 1966; Amrein, 1967; Baetjer, 1968; Previte et al, 1970; Won and Ross, 1971; Bell and Moore, 1974; Jiang et al, 2000; Rice et al, 2005). These effects can be dramatic: in experimental murine typhus, weather-associated changes in ambient laboratory temperature (from 29.4–36.6 to 18.3–22.8°C) shifted mortality rates from 9 to 100% (Moragues and Pinkerton, 1944).…”