Pathological Studies on Lung Abscesses in Sheep Slaughtered in Kashmir Valley, India

Abstract

The present study was conducted in Kashmir valley of India to investigate the prevalence and pathology of lung abscesses in sheep, slaughtered in different organized abattoirs. These abattoirs were visited between January 2010 to February 2011 and a total of 1455 lungs were examined. Out of these 18.9% lungs had abscesses, with higher incidence in young sheep (60%) than in adult ones (40%). Grossly, abscesses were observed in one or more lung lobes and were either single or multiple. In majority of lungs, abscess sizes varied from pea to walnut size, but in some cases large abscesses were also observed. Histopathologically, abscesses were characterized by a central caseo-necrotic core surrounded by pyogenic membrane with infiltration of polymorphonuclear cells and few mononuclear cells and macrophages. Most of the abscesses revealed presence of Gram positive bacterial infection where as chronic abscesses indicated both Gram positive and Gram negative bacterial infection. Fibrous tissue proliferation around the pyogenic membrane of the chronic abscesses was noticed. Disruption and disorientation of elastin fibres was also a prominent feature. Increased concentration of both acid and neutral mucopolysaccharides was observed in and around the lesion. Purulent material of abscesses revealed marked metachromasia. The study revealed that lung abscesses in domestic sheep are highly prevalent in Kashmir valley. Thus, there is a need to introduce appropriate control measures of diseases affecting the lungs to minimize the incidence of lung affections and hence reduce the ensuing economic losses.