Retrospective study of fatal pneumonia in racehorses

Abstract

Respiratory diseases have a major impact on racehorses in training and are often cited as the second most common reason of horses failing to perform. Cases were submitted by the California Horse Racing Board to the California Animal Health and Food Safety laboratory for postmortem examination between January 1, 2005 and December 31, 2014. We determined the demographics of racehorses with fatal pneumonia, characterized the pathologic findings in animals with a postmortem diagnosis of respiratory infection, and determined the most significant pathogens associated with lower respiratory tract disease. We analyzed autopsy reports from 83 horses with a diagnosis of pneumonia, bronchopneumonia, and/or pleuropneumonia. The most common presentation was pleuropneumonia (71% of cases), with extensive areas of lytic necrosis and abscesses of the pulmonary parenchyma. Streptococcus equi ssp. zooepidemicus, a normal mucosal commensal of the upper respiratory tract of healthy horses, was the most commonly isolated organism (72% of cases), either in pure culture or accompanied by other aerobic or anaerobic bacteria. Its presence in the pulmonary parenchyma is associated with severe and extensive damage to the lung. Furthermore, this agent has zoonotic potential, which stresses the importance of early detection and proper management of cases of pneumonia in racehorses.

Lung lesions of slaughtered horses in southern Brazil

“…This condition has been previously described in Brazil in two horses (Panziera et al 2014, Estima-Silva et al 2017, and in this study a suggestive diagnosis of EMPF by EHV-5 in one of the cases was obtained by the association of the gross and the microscopic features. Similarly to the previously described changes in a race horse, the multiple intranuclear inclusion bodies associated to the interstitial fibrosis are characteristic of this condition (Williams et al 2007, Carvallo et al 2017. The histological features of EMPF are distinct from other causes of fibrosis (Williams et al 2007), as it was observed in the remaining two cases of interstitial fibrosis, in which a specific cause could not be determined.…”

“…When these pathogens are compared, S. equi subsp. zooepidemicus has a broader tissue tropism (Carvallo et al 2017), being able to infect, in addition to the lungs, other reproductive organs (Erol et al 2012). On the other hand, S. equi subsp.…”

“…Respiratory diseases cause significant veterinary costs, reduce performance and require the withdrawal of racehorses (Wood et al 2005, Carvallo et al 2017. Bacterial pneumonia in foals is mainly caused by Rhodococcus equi and Escherichia coli (Lakritz et al 1993), while in adult horses it has been associated to upper respiratory tract normal flora and opportunist pathogens that reach the lower respiratory tract, such as Streptococcus equi subsp.…”

“…zooepidemicus and S. equi subsp. equi (Carvallo et al 2017). Still, data for the causes of pneumonia in slaughtered horses have not yet been described.…”

Sekrete aus den Nasennebenhöhlen des Pferdes – Untersuchungsmöglichkeiten und deren diagnostische Aussagekraft

“…zooepidemicus eine wichtige Bedeutung zuzukommen scheint [11,12]. Dieser Keim ist sowohl bekannter Kommensale der oberen Atemwege des Pferdes, aber nachweislich auch opportunistischer Erreger bei schweren Infektionen der tiefen Atemwege [13].…”