Alligators as West Nile Virus Amplifiers
Figure. Daily viremia titers. A) Injected alligators held at 32°C (◊, *, ○, Δ, □, +) and their tankmates (x, ), B) Injected alligators held at 27°C (◊, ○, *, Δ, □, +). Tankmates did not become viremic. C) Orally infected alligators held at 32°F (◊, □) and their tankmates (○, , *, +, x, Δ). D) Orally infected alligators held at 27°C (◊, ○, *, Δ, □, +) and their tankmates (x, ). Blood samples were collected from each alligator for virus isolation once a day for 15 days postinfection. (Some tankmate alligators were bled daily through day 21 postinfection.) After day 15, alligators were bled biweekly through day 31 postinfection. West Nile viremia was quantified by using a Vero cell plaque assay. Plaques were counted after 4 days of incubation. The threshold of detection was 1.7 log10 PFU/mL of serum. Values <101.7 were considered to be zero.