Streptococcal diseases occur in humans and animals. Most species are host-specific, and outbreaks of disease occur most often when large numbers of animals or people are housed in close confinement. Streptococcus equi subspecies zooepidemicus (SEZ) is a mucosal commensal with a wide host range. Most commonly found in horses, it can cause a variety of respiratory and infectious diseases. It has also been associated with disease outbreaks in sheep, goats, deer, lambs, and guinea pigs. There have been recent reports of SEZ outbreaks in dogs in shelters. Affected animals die acutely of severe fatal respiratory disease. Two cases of SEZ infection in shelter cats were described in this report. Both cats were adults, were housed in separate shelters, and had lived in the shelter for 3 and 9 months before disease onset. Both cats had acute onset of illness and vague clinical signs; 1 became acutely ill. Both cats died within 24 hours of developing the illness. Upon necropsy, severe rhinitis and meningitis were found; SEZ was cultured and then identified via polymerase chain reaction testing. The heaviest growth of organisms was from the nasal passages and brain, suggesting the meningitis had an olfactory route of infection. The authors report this as the first case of SEZ in cats and infection as rhinitis and meningitis. The pathogenesis is unknown, and there were no outbreaks in either shelter. Both cats were FeLV/FIV negative.
SEZ is increasingly recognized as a virulent pathogen in dogs in shelters. There have been numerous reports of these outbreaks worldwide. This case report suggests that, although rare in cats, this pathogen should be considered in the differential diagnosis of cats with sinusitis, rhinitis, and neurologic disease. SEZ is of zoonotic importance, and most cases affecting humans have been associated with the consumption of contaminated milk products.