Blastomyces dermatitidis is a fungal agent that affects humans and animals, primarily dogs. It may be associated with environmental conditions, such as sandy soil, organic matter, waterways, and construction sites. A cluster of blastomycosis was observed in 8 people and 4 dogs in a rural North Carolina community. An epidemiologic study of theses cases failed to show a common source for human and canine patients. Four of the patients attended the same school and were involved in different outdoor after-school activities. None of the dogs had contact with the human patients or other infected dogs. This report underscores the difficulty in investigating blastomycosis outbreaks.

COMMENTARY: This article is of particular interest to those of us in the area of Blastomyces endemicity. Our laboratory has experienced a sizable increase in serologically positive dogs during the months of June and July, 2006. A limited epidemiological investigation into our obviously increased incidence has resulted in the same frustrations as in the cluster of cases reported in this paper. As a laboratory professional, I do disagree with the authors that there is a lack of specificity in the serological tests available, especially the agar gel immunodiffusion test (AGID).

Human and canine pulmonary blastomycosis, North Carolina, 2001-2002. MacDonald PDM, Langley RL, Gerkin SR, et al. EMERG INFECT DIS 12:1242-1244, 2006.