Experimental reproduction of the egg drop syndrome 1976 with a haemagglutinating adenovirus.

The experimental reproduction of an egg drop syndrome is described. Experimental oral infection of fowl with a haemagglutinating adenovirus resulted in the production of shell-less, soft-shelled and thin-shelled eggs in association with loss of egg shell colour and were similar to those changes seen in the egg drop syndrome 1976 (EDS 76). The first changes observed were 7 days post-inoculation when loss of egg shell pigmentation occurred. Colour patterns did not return to normal until 25 days post-inoculation. Thinning of egg shells was first seen 1 day after the loss of pigmentation and by 9 days post-inoculation soft-shelled and shell-less eggs were laid. From 13-16 days post-inoculation between 25 and 40% of eggs laid were either shell-less, soft-shelled or very thin-shelled. The majority of birds were laying normal eggs by 24 days post-inoculation. In spite of the marked egg shell changes the overall daily egg production remained at approximately 80% during the 17-week experimental period.