Fowlpox virus outbreaks in Kosovan layer flocks: an evidence of vaccination failure

Abstract

In October 2008, two outbreaks of fowlpox virus (FPV) were registered at a laying hen facility in Northwest Kosovo despite prior vaccination of birds at 14-15 weeks of age. Both forms of the disease (cutaneous and diphtheritic) were confirmed in both outbreaks. During the outbreak, 30 samples from the cutaneous nodular lesions and fibro-necrotic proliferative lesions (from mucosa of the mouth and pharyngeal mucous membrane), were randomly selected from 350 severely infected birds for laboratory analysis. Avipox-specic PCR, employing one primer set that framed a region within the avian poxvirus 4b core protein gene, enabled the detection of FPV-specific DNA from all three pooled samples tested. This provides the first irrefutable evidence of FPV in the Kosovan flocks, also supporting the failure of current vaccination programmes to contain FPV in this area. The relevance of these results to the wider poultry industry, and to developing our understanding of this disease and its future treatment, are discussed.