Development of Experimental Myopia in Chicks in a Natural Environment.

Purpose: The hypothesis that outdoor exposure might protect against myopia has generated much interest, although available data find only modest clinical efficacy. We tested the effect of outdoor rearing on form-deprivation myopia in chicks, a myopia model markedly inhibited by high-intensity indoor laboratory lighting.

Methods: Unilaterally goggled cohorts of White Leghorn chicks were maintained in a species-appropriate, outdoor rural setting during daylight hours to the extent permitted by weather.

Evaluation of the efficacy of a live fowlpox-vectored infectious laryngotracheitis/avian encephalomyelitis vaccine against ILT viral challenge.

Infectious laryngotracheitis (ILT) is caused by an alphaherpesvirus, and latency can be produced by previous exposure to vaccine virus. The main sites of latency for the ILT virus have been shown to be the trigeminal ganglion and the trachea. Reactivation of latent virus is one factor related to the production of clinical signs.