Monitoring for atrophic rhinitis: five years' experience with a pilot control scheme.

A pilot control scheme for atrophic rhinitis was initiated in Britain by the Pig Health Control Association in January 1977. To qualify, herds must have maintained a low degree of turbinate damage and not shown clinical signs of atrophic rhinitis over a period of at least two years. Qualifying herds can import pigs only from other qualifying herds or via hysterectomy/hysterotomy methods. During the first five years, 45 herds qualified at some stage, and at the end of 1982, 34 herds (comprising about 7200 sows) were still listed. Although the scheme is not related to particular infectious agents, atrophic rhinitis has not appeared within it or in herds established entirely from listed herds, despite the fact that 31 of the 45 qualifying herds had imported stock from 15 other qualifying herds.