In 1999, a mysterious outbreak of human encephalitis occurred in the northeastern United States. The cause was tentatively identified as St. Louis encephalitis virus. At the same time, an unusual...

In 1999, a mysterious outbreak of human encephalitis occurred in the northeastern United States. The cause was tentatively identified as St. Louis encephalitis virus. At the same time, an unusual number of dead birds were noticed along the northeastern Atlantic coast. Figure 14.36 shows genetic relationships of three known encephalitis viruses (St. Louis, Japanese, and West Nile) and several viruses iso lated from the birds, from two human patients that died, from one dead horse, and from mosquitoes. (Data compiled from Anderson et al. 1999 and Lanciotti et al. 1999.)

Does this cladogram suggest how the disease might be spread?