Nocardiain naturally acquired and experimental infections in animals

Abstract

There are three commonly recognized species ofNocardiathat cause disease in a large variety of animals including humans. In the United States, pulmonary or systemic nocardiosis in humans caused byN. asteroidesis most frequently diagnosed. It should be noted thatN. brasiliensiscan cause nocardiosis also. In Central and South America mycetomas induced byN. brasiliensisappear to be more prevalent even thoughN. asteroidescan be seen in this type of infection. Sporadic cases of both mycetoma and nocardiosis caused byN. caviaehave been reported. These three species ofNocardiaappear to be present in the soils of most countries; butN. asteroidesis more frequently isolated in the temperate climates whereasN. brasiliensispredominates in the tropical and subtropical regions of the world. No specific geographic distribution has been noted withN. caviae. Infections involving these three species of bacteria are, therefore, worldwide in occurrence. Even though nocardial infections in both humans and animals were recognized as early as 1888, traditionally, they have been considered rare in frequency as compared to many other infectious diseases. This is a perception that probably is not accurate. During the past twenty years, greater diagnostic awareness combined with more intensive medical and veterinary surveillance have resulted in significantly increased recognition of disease caused by these aerobic actinomycetes.