Three-month-old and 8-month-old chickens were inoculated subcutaneously with a single, small dose of WE virus calculated to represent that which could be inoculated by a naturally infected mosquito. Each chicken was bled for determination of the viremia and antibody pattern. A similar study was made with SLE virus.
The viremia period for WE virus in the majority of adult chickens lasted only 2 days. SLE virus was present in the blood of about half of adult chickens on the 2nd and 3rd days after inoculation and persisted in a few individual birds for longer periods of time. Most of the chickens inoculated with WE virus had HI titers of 1:320 or greater by the 2nd week after inoculation. Although there was some decrease in HI-antibody titers to WE, this antibody persisted at detectable levels for at least 1 year. In these chickens strong neutralization indices developed by the 2nd week, and this type of antibody persisted for at least the 9-week observation period. In adult chickens inoculated with SLE virus HI antibody developed by the 2nd week, and although the titers declined during the next 9 months, every chicken tested had detectable antibody at the end of the observation period. Nineteen of these chickens had neutralization indices of 101.5 or greater during the 10-week observation period. Individual chickens showed considerable variation in their HI and neutralizing-antibody response to SLE infections.
These data help to define the manner in which adult chickens may be used as sentinel animals to detect arbovirus activity, and they provide a basis for interpreting field data.
Formerly Chief, Virus Investigations, Disease Ecology Section, Technology Branch, Communicable Disease Center, Greeley, Colorado. Present address: Chief, Community Studies Section, Pesticide Program, National Communicable Disease Center, Atlanta, Georgia 30333.
U. S. Army Chemical Corps, Dugway Proving Grounds, Dugway, Utah.
Disease Ecology Section, Technology Branch, Communicable Disease Center, Greeley, Colorado.