Susceptibility of Dogs and Cats to Rift Valley Fever by Inhalation or Ingestion of Virus

Abstract

Eight- to 10-week-old puppies and kittens were found to be susceptible to infection with Rift Valley fever virus (RVFV) given in graduated doses by the respiratory route, but they were not susceptible to ingested RVFV. When the animals were exposed to infectious aerosols, inhaled doses of as low as 5–36 times the 50% intracerebral lethal dose for mice (micld₅₀) of RVFV infected six of eight puppies and two of four kittens. No outward sign of clinical disease developed in these animals, but viremia was detected in some. A neutralizing-antibody response after exposure was the ultimate criterion for infection. Puppies and kittens were not infected after they ingested skim milk containing up to 6.4 log₁₀micld₅₀ of RVFV.