A Clonal Outbreak of Acute Fatal Hemorrhagic Pneumonia in Intensively Housed (Shelter) Dogs Caused byStreptococcus equisubsp.zooepidemicus

Abstract

An outbreak of acute, fatal, hemorrhagic pneumonia was observed in more than 1,000 mixed breed dogs in a single animal shelter. The Department of Anatomic Pathology at the University of California at Davis School of Veterinary Medicine performed necropsies on dogs that were found moribund in acute respiratory distress or found dead with evidence of nasal bleeding. All dogs had hemothorax and an acute, fibrinosuppurative pneumonia. Large numbers of gram-positive cocci were observed within the lungs of all dogs and within septic thromboemboli of remote organs in about 50% of cases. Bacterial cultures from the dogs and their environment revealed widespread beta-hemolytic Streptococus equi subspecies zooepidemicus (Lancefield Group C). Extensive diagnostic testing failed to reveal the consistent presence of copathogens in individual cases. The clinical, epidemiologic, molecular biologic, and pathologic data indicate that a single clone of S. zooepidemicus was the cause of an acutely fatal respiratory infection in these dogs.

Characterization and Protective Immunogenicity of the SzM Protein of Streptococcus zooepidemicus NC78 from a Clonal Outbreak of Equine Respiratory Disease

“…S. zooepidemicus has been implicated in a wide range of opportunistic infections of the respiratory and reproductive tracts in many vertebrate hosts. There also is evidence of the emergence of specific clones associated with outbreaks of severe respiratory disease in shelter dogs, horses, pigs, and monkeys (7,24,25). In the early 1900s, pneumonia associated with S. zooepidemicus caused great losses in civil and military horse populations, with mortality rates as high as 15% and prolonged periods of convalescence (26,27).…”

“…S. zooepidemicus opportunistically produces respiratory disease in situations involving viral infections, heat stress, or prolonged transportation (4). Select clones can be devastating pathogens in intensively housed dogs and guinea pigs and in humans following consumption of contaminated milk or cheese (5)(6)(7).…”

Risk reduction and management strategies to prevent transmission of infectious disease among dogs at dog shows, sporting events, and other canine group settings

“…This has been illustrated in several documented outbreaks of canine infectious disease, 7,35,39,57,99,100 in which high population density or an increase in direct contact among dogs were evident and considered to have contributed.…”

Identification of Three Novel Superantigen-Encoding Genes in Streptococcus equi subsp. zooepidemicus , szeF , szeN , and szeP

“…zooepidemicus is the most frequently isolated opportunistic pathogen of horses; it is associated with inflammatory airway disease in Thoroughbred racehorses (50,51), uterine infections in mares (21,41), and ulcerative keratitis (8). It is also associated with disease in a wide range of other animal hosts, including cattle (39), sheep (25,44), pigs (38,42), monkeys (38,42), dogs (12,34), and humans (7,17,19). The broad range of hosts and tissues infected by S. equi subsp.…”