Serological evidence of Rickettsia parkeri as the etiological agent of rickettsiosis in Uruguay

We report three new rickettsiosis human cases in Uruguay. The three clinical cases presented clinical manifestations similar to previous reported cases of Rickettsia parkeri in the United States; that is mild fever (< 40 ºC), malaise, headache, rash, inoculation eschar at the tick bite site, regional lymphadenopathy, and no lethality. Serological antibody-absorption tests with purified antigens of R. parkeri and Rickettsia rickettsii, associated with immunofluorescence assay indicated that the patients in two cases were infected by R. parkeri. Epidemiological and clinical evidences, coupled with our serological analysis, suggest that R. parkeri is the etiological agent of human cases of spotted fever in Uruguay, a disease that has been recognized in that country as cutaneous-ganglionar rickettsiosis.

Importance of the direct fresh examination in the diagnosis of cutaneous sporotrichosis

BACKGROUND

To date the direct fresh examination has not been considered, except by a few authors, as a valid laboratory procedure for the diagnosis of cutaneous sporotrichosis.

METHODS

Forty-two patients with cutaneous sporotrichosis (36 lymphangitic and six fixed) were studied. Pus was obtained through digital compression of opened lesions followed by collection with a spatula and examination of the material between the slide and the coverslip. Cultures on Sabouraud's glucose agar slants with cloramphenicol and cicloheximide were made in all cases.

RESULTS

Direct, fresh examination asteroid bodies of Sporothrix schenckii were found in 85.7% of the cases, which allowed the authors to immediately diagnose the disease. Cultures confirmed the diagnosis in 95.2% of the patients.

CONCLUSIONS

Fastness, simplicity and low cost of the fresh examination lead us to recommend systematic use of the method for primary diagnosis of the disease, mainly at first level public health laboratories.

[Tinea nigra. 1st clinical case in Uruguay]

The first case in Uruguay of 'tinea nigra' is described in a 44-year-old male patient with a maculous pigmented lesion on the right foot. It represents the most meridional case of the disease yet recorded in South America. Exophiala werneckii was isolated in cultures (strain 1905 IHM).

[Serology of cutaneous sporotrichosis]

Sporothrix schenckii antigens were tested with seventy-nine sera from human cases of sporotrichosis for their value in the serological diagnosis of extracutaneous forms of the disease. 55.7% of the sera reacted in the tube agglutination test; 29.1% of them were positive by counter immunoelectrophoresis and only 7.6% reacted in the simple immunodiffusion test. There was a clear correlation between agglutination titers and the respective reactivity of sera by counter immunoelectrophoresis. By immunoelectrophoresis, 2 different anodic precipitin bands were observed between S. schenckii metabolic antigen and anti-Sporothrix hyperimmune animal sera. Since no false positive reactions were found in sera from patients with other mycoses, and considering the simplicity of the antigen preparation, we agree with previous authors that these methods may be useful for the detection of visceral forms of sporotrichosis.

Electrophoretic migration of Paracoccidioides brasiliensis specific antigenic fraction

Using the technique of immunoelectroosmophoresis-immunodiffusion (IEOP-ID), two antigenic fractions of Paracoccidioides brasiliensis one of them species-specific, produced precipitin bands in both the cathodic and anodic zones. Reactions of complete identity among the bands formed in these zones were demonstrated by a modification of the technique, employing additional wells around the central antigen well. Such bands would correspond to a simple diffusion of the corresponding antigenic fractions rather than to active electrophoretic migration.

Paracoccidioidal infection in the wife of a patient with paracoccidioidomycosis

Three agar immunoprecipitin techniques (double immunodiffusion, immunoelectrophoresis and immunoelectroosmophoresis-immunodiffusion) made with paracoccidioidin and serum of a paracoccidioidomycosis patient's wife, permitted us to observe a specific band in 6 successive samples of blood taken from the wife over a period of 21 months. The case represents an example of a subclinical paracoccidioidomycosis infection that is usually diagnosed in its disseminated, progressive form. Three possible sources of infection are discussed. But an interhuman contagion appears to be the most feasible.

[Microsporum gypseum: endothrix parasitism with medium or large spores in hair of children]

Five cases of tinea corporis in children by Microsporum gypseum are presented. In four of them an endothrix type of parasitism with arthrospores 4 to 8 microns in diameter was observed. In the other case ectothrix and endothrix types of parasitism were seen in different hairs. Endothrix infection of hairs by species of the genus Microsporum has not been clearly demonstrated until the present. Three isolates were identified as Nannazzia gypsea of the "+" mating type.