Nocardiosis: An Emerging Infectious Actinomycetic Disease of Humans and Animals

In recent past, many infectious diseases of diverse etiologies have emerged, which resulted into significant morbidity and mortality in humans as well as in a variety of animals. Among these diseases, nocardiosis is one, which is reported from developing and developed nations; and can occur, in sporadic and epidemic form. Nocardiosis is an emerging actinomycetic saprozoonosis of public health, and economic importance. Disease is caused by several species of Nocardia, which exists as saprobe in the soil. Nocardia asteroides is the principal species, which is implicated in various clinical disorders of humans and animals including birds. Soil serves as the source, and reservoir of infection; and the respiratory tract is considered as the chief portal of entry of organism. Rarely, Nocardia can enter the body through traumatic injury or wound. There are evidences to believe that humans and animals may acquire the infection from the saprobic environment where the organism exists. The identification and isolation of the pathogen in the clinical specimens both by direct microscopy, and culture still remain the gold standard of diagnosis of nocardiosis. Antimicrobial agents are used as the main stay of treatment. Immediate attention to traumatic injury to the skin, avoiding the visit to dusty environment, early diagnosis and prompt treatment in immunocompromised patients, sanitation in milking parlour, adequate udder hygiene, and proper disposal of excreta will certainly minimise the incidence of nocardiosis both in humans and animals. Further studies on the growing role of Nocardia in various clinical disorders of humans and animals will be rewarding. The development of effective, safe, and low cost chemotherapeutic agents for the management of disease is emphasized.