Studies in the Epidemiology of Myxomatosis in California

Regnery, D. C. (Dept. Biological Sciences, Stanford Univ., Stanford, Calif. 94305) and I. D. Marshall. Studies in the epidemiology of myxomatosis in California. IV. The susceptibility of six Leporid species to Californian myxoma virus and the relative infectivity of their tumors for mosquitoes. Amer J Epidem 94: 508–513, 1971.—Tumors developed in each of four species of North American rabbits (Sylvilagus audubonii, S. floridanus, S. idahoensis, and S. nuttallii) following mosquito transfers of Californian myxoma virus but attempts to transfer virus via mosquitoes from the four were unsuccessful. Assays of the virus titer in the tumor tissues of S. audubonii, S. floridanus, and S. nuttallii indicated that infectious virus was present in the tissues in amounts below that usually required for effective mosquito transfer. The South American rabbit (S. brasiliensis) gave a negative response to Californian myxoma virus but was later infected with South American (Lausanne strain) myxoma virus. No tumors were produced in jack rabbits (Lepus californicus) after being inoculated with myxoma virus. Later one individual tested developed infectious tumors when it was infected with European hare fibroma. It is postulated that the brush rabbit (S. bachmani) is the only Leporid among those tested that can serve as a reservoir for Californian myxoma virus.