Detection ofin nasal and laryngeal swab specimens in endemically infected pig herds.

Abstract

BACKGROUND: Apparently, laryngeal swabs (LS) are more sensitive than nasal swabs (NS) and allow earlier detection ofby PCR. However, antecedents about the compared detection ofwith NS and LS in growing pigs, from naturally infected herds, are lacking in the literature. Thus, this study compared the PCR detection offrom NS and LS in pigs of various ages. METHODS: A longitudinal study was performed at two farms where NS and LS were collected from three consecutive groups of 20 pigs at 3, 6, 10, 16 and 22 weeks of age. All samples were analysed by nested PCR fordetection. RESULTS: The probability of PCR detection ofwas higher in LS for pigs of all ages (odds ratio (OR)=1.87; 95 per cent confidence interval (CI) 1.31-2.67) and in 22-week-old pigs (OR=4.87; 95 per cent CI 2.86-8.30). The agreement between both sample types was low to moderate (kappa 0.087-0.508), highlighting thatdoes not appear to colonise the respiratory tract in a generalised and consistent fashion. CONCLUSIONS: The results suggest that LS could be employed at different ages to achieve greater bacterial detection. Considering that LS is a minimally invasive, highly sensitive sample compared with the traditional NS, it could be suggested to employ this sample type fordetection in naturally infected pigs.