Molecular epidemiology of Blastomyces dermatitidis.

The inhalation of conidia of Blastomyces dermatitidis, a fungus found in soil, causes disease in humans and animals. We studied the genetic diversity of this pathogen by extracting DNA yeasts and analyzing them with a polymerase chain reaction (PCR)-based typing system we developed, which used restriction fragment analysis of amplicons from the regions between the rDNA repeats and allowed us to class isolates into 3 major groups. Strains were further differentiated by use of PCR fingerprinting with 3 different primers. Fifty-nine isolates collected over 35 years from 15 regions (United States, India, Africa, Canada) were analyzed. Genotypic groups A, B, and C contained 17, 23, and 19 isolates, which were divided into 5, 15, and 12 types, respectively. All 16 isolates from North America in group A were from the upper midwestern United States or Canada, whereas 0 of 20 isolates from the southeastern United States were in group A. Studies of the largest collection from 1 locale (Eagle River, WI), revealed that the soil isolates studied were not responsible for the majority of cases in this outbreak, as previously proposed, and that >1 strain was present in the environment and in patients. Overall, these results provide a tool for the epidemiological study of blastomycosis and illuminate the genetic and geographic diversity of this important pathogen.

Virulent isolates and mutants of Blastomyces in mice: a legacy for studies of pathogenesis.

This article provides information on the history of Blastomyces dermatitidis isolates and spontaneous mutants, the relationship with maintenance of cultures, and their virulence as quantified in murine models. Virulent isolates have been obtained from soil or from patients. Regardless of origin, mutants attenuated in virulence have sometimes arisen from storage as frozen yeast, frozen mycelia, or refrigerated yeast or serial passage in vitro at 35 degrees to 37 degrees C. Once virulence is lost, reversion to the virulent phenotype (even after serial passage in animals) has not been seen. These data, methods, and isolates provide a basis for future studies of virulence factors.

Nomenclature of fungal diseases: a report and recommendations from a Sub-Committee of the International Society for Human and Animal Mycology (ISHAM).

The ISHAM Mycoses Nomenclature Committee has considered the present status of fungal disease names. It suggests that the traditional approach to mycoses nomenclature in which the name of a causative taxon is suffixed with '-asis', '-iasis', '-osis' or '-mycosis' leads to names that are frequently unstable with respect to subsequent taxonomic and clinico-epidemiological changes. It is therefore recommended that individual mycoses should be named as often as possible in the form 'pathology A due to/caused by fungus X' or '[adjectival] fungus X pathology A' in preference to construction of names based solely on fungal taxa. A list of recommended mycosis names retained for their long tradition or intrinsic convenience is provided, together with a combined index and list of rejected names.

Disseminated Dactylaria gallopava infection in a diabetic patient with chronic lymphocytic leukemia of the T-cell type.

A 62-year-old male with a 20-year history of diabetes and three-year history of adult T-cell lymphocytic leukemia developed a systemic infection with Dactylaria gallopava. At autopsy the fungus was found in the brain, lungs, liver, spleen, and kidney. The organism has caused disease in chickens and turkey poults and has been found in chicken litter, hot springs, and the effluent of a thermonuclear reactor. This report documents the second human infection and the first case of disseminated human dactylariosis.

Two outbreaks of blastomycosis along rivers in Wisconsin. Isolation of Blastomyces dermatitidis from riverbank soil and evidence of its transmission along waterways.

Blastomycosis cannot yet be prevented or controlled, in part because the natural habitat of the causative fungus, Blastomyces dermatitidis, remains ill defined. In investigating 2 outbreaks of blastomycosis that occurred in the summer of 1985 among persons engaged in activities along rivers in contiguous central Wisconsin counties, we isolated B. dermatitidis from soil at one of the riverbanks. Blastomycosis developed in 7 (58%) of 12 residents and guests who had gathered at a pheasant farm on the Tomorrow River in early May, and in 7 (88%) of 8 boys and 1 adult who had visited a site on the Crystal River in early June. Of the 14 patients, 13 (93%) were symptomatic. Two patients visiting the sites only once became ill 23 and 78 days after exposure, respectively. We traced one outbreak to fishing from the bank of the Tomorrow River, and the other to climbing into an underground timber fort along the Crystal River. A culture of soil and organic debris from the fishing site yielded B. dermatitidis. From these and other outbreaks, and studies of endemic disease, we conclude that riverbanks can be a natural habitat of B. dermatitidis, and that the environment around waterways represents the most important site yet identified for transmission of B. dermatitidis.

Mycotic morbidity--an occupational risk for mycologists.

Classical mycologists may be at a greater risk for infection with organisms under investigation than medical mycologists. The methods of infection of human beings by systemic mycotic pathogens is known. These principles can be used to develop good laboratory practices for classical mycological investigators. Newly recognized fungal pathogens and a more susceptible population may cause more laboratory infections. Minimal safety practices to prevent mycotic morbidity are described.

Red-pigmented Histoplasma capsulatum--an unusual variant.

An unusual variant of Histoplasma capsulatum was isolated from a canebrake. The mycelial form produced a red pigment that diffused into the medium and which was also present in the cell walls of the mycelium, microconidia and macroconidia. The yeast cells were not pigmented nor did they produce any pigment.

Epidermophyton floccosum infection in a dog from the United States.

Epidermophyton floccosum was isolated from a lesion of dermatophytosis on a dog with hyperadrenocorticism. This report is, to our knowledge, the first unequivocally documented case of canine infection in the United States.

Observation of Paragonimus westermani eggs in sputum after digestion for mycobacteria culture.

Pulmonary paragonimiasis was diagnosed by the observation of Paragonimus westermani eggs on smears of sputum concentrated for the detection of mycobacteria and on the culture plates. The eggs were distorted but recognizable.

Evaluation of commercial reagents to identify the exoantigens of Blastomyces dermatitidis, Coccidioides immitis, and Histoplasma species cultures.

Commercially available individual serologic reagents (Nolan/Scott Biological Laboratories, Inc.) and an "exoantigen identification system" (a kit supplied by Immuno-Mycologics, Inc.) were evaluated at two laboratories for their possible application in the microimmunodiffusion test to identify Blastomyces dermatitidis, Coccidioides immitis, and Histoplasma species. Both laboratories accurately identified all the cultures, and comparison of the results obtained with the commercial products and those established with the conventional methods performed by a third control laboratory demonstrated full agreement. The use of these two commercial products is recommended for the immunologic identification of cultures suspected of being B. dermatitidis, C. immitis, and Histoplasma species. It was observed, however, that the exoantigen reactions for four B. dermatitidis and two C. immitis isolates were much sharper and more readable with the individual reagents than the reactions observed with the kit.

Naturally acquired rabies in an eastern chipmunk (Tamias striatus).

Rabies in an Eastern chipmunk was detected by fluorescent-antibody testing and mouse inoculation. The results were independently confirmed, and the virus was recovered from tissue culture.