§ 51. Sir A. Hurdasked the Minister of Agriculture, Fisheries and Food what conclusions he has reached from studying the constant recurrence of outbreaks of fowl pest; in how many cases the birds had been treated once or more with a vaccine approved by his Department; and to what extent he expects that continuing research in the laboratory and experience on the farm will result in a more effective vaccine being produced.
§ Mr. SoamesThe following conclusions can be drawn from the first 10 months experience of the control of fowl pest by vaccination. First, where vaccination is widely and properly practised control is as successful as it was under the slaughter policy: this is borne out by experience in Norfolk and Suffolk, where vaccine has been widely used and disease incidence has been much lower8W than in previous years. The amount of virus released from an infected vaccinated flock is less than from a similar unvaccinated flock. Second, where vaccination is not widely practised and disease strikes outbreaks are numerous and spread is rapid: this is the situation in Lancashire and more recently in Cheshire, where 84 of the 98 outbreaks which were confirmed in January occurred in unvaccinated or only partly vaccinated flocks. Were it not for the large number of outbreaks in these two counties the position in England and Wales would in fact be much better than in previous years. Third, where disease does strike a vaccinated flock, it is usually less severe and the amount of illness and mortality less than in infected unvaccinated flocks.
Of 1,896 outbreaks of fowl pest in the period April, 1962, to January, 1963, 809 occurred in flocks which had not been vaccinated, 452 in flocks which had been partly vaccinated, and 635 in fully vaccinated flocks. In about one-third of these 635 cases, disease appeared before maximum protection had developed.
Research into fowl pest vaccine and vaccination techniques is a continuing process and we have only had just over one year's experience of reliance on vaccination. It would be contrary to experience with other vaccines, and indeed in other fields of research if progress were not made and an even more effective vaccine developed.