The leprosy agents Mycobacterium lepromatosis and Mycobacterium leprae in Mexico.

BACKGROUND: Mycobacterium leprae was the only known cause of leprosy until 2008, when a new species, named Mycobacterium lepromatosis, was found to cause diffuse lepromatous leprosy (DLL), a unique form of leprosy endemic in Mexico. METHODS: We sought to differentiate the leprosy agents among 120 Mexican patients with various clinical forms of leprosy and to compare their relative prevalences and disease features. Archived skin biopsy specimens from these patients were tested for both M. leprae and M. lepromatosis using polymerase chain reaction-based species-specific assays. RESULTS: Etiologic species were confirmed in 87 (72.5%) patients, of whom 55 were infected with M. lepromatosis, 18 with M. leprae, and 14 with both organisms. The endemic regions of each agent differed but overlapped. Patients with M. lepromatosis were younger and were distributed across more states; their clinical diagnoses included DLL (n = 13), lepromatous leprosy (LL) (n = 34), and eight other forms of leprosy. By contrast, the diagnoses of patients with M. leprae did not include DLL but did include LL (n = 15) and three other forms of leprosy. Thus, M. lepromatosis caused DLL specifically (P = 0.023). Patients with M. lepromatosis also showed more variable skin lesions; the extremities were the most common sites of biopsy in these patients. Finally, patients with dual infections manifested all clinical forms and accounted for 16.1% of all species-confirmed cases. CONCLUSIONS: Mycobacterium lepromatosis is another cause of leprosy and is probably more prevalent than M. leprae in Mexico. It mainly causes LL and also specifically DLL. Dual infections caused by both species may occur in endemic areas.

Diffuse leprosy of Lucio and Latapí: a histologic study.

BACKGROUND AND PURPOSE: Ladislao de la Pascua described the spotted or lazarine leprosy for first time in 1844. Later on, Lucio and Alvarado studied and published it with the same names in 1852. Latapí re-discovered it in 1938 and reported it as 'Spotted' leprosy of Lucio in 1948. Frenken named it diffuse leprosy of Lucio and Latapí in 1963. Latapí and Chévez-Zamora explained that the fundamental condition of this variety of leprosy was a diffuse generalised cutaneous infiltration, naming it pure and primitive diffuse lepromatosis, upon which necrotising lesions develop, calling these lesions Fenómeno de Lucio or erythema necrotisans. A great number of histopathological reports have addressed the study of Lucio's phenomenon, and few about the histologic changes that take place in the course of diffuse lepromatous leprosy. The purpose of this work is to report the histologic findings observed in the study of 170 cutaneous biopsies of diffuse leprosy of Lucio and Latapí and 30 of Lucio's phenomenon. METHODS: This is a retrospective study, which included the examination of 200 biopsy skin specimens from 199 patients with diffuse leprosy at different course of the disease. These cases were diagnosed in Mexico from 1970 to 2004. RESULTS: The histologic examination revealed a vascular pattern affecting all cutaneous vessels, characterised by five outstanding features: a) colonisation of endothelial cells by acid-fast bacilli, b) endothelial proliferation and marked thickening of vessel walls to the point of obliteration, c) angiogenesis, d) vascular ectasia, and e) thrombosis. Necrotising lesions seen in diffuse lepromatous leprosy displayed two histopathological patterns: one of them, non-inflammatory occlusive vasculopathy and, the other one, occlusive vasculopathy, leukocytoclastic vasculitis, large neutrophilic infiltrate and lobular panniculitis. The first appeared as a result of the course of the occlusive vasculopathy produced by the colonisation of endothelial cells by Mycobacterium leprae. The second, as a result of a previous occlusive vasculopathy plus a leprosy reaction which is considered here as variant of ENL. CONCLUSIONS: Endothelial cell injury appears to be the main event in the pathogenesis of diffuse leprosy of Lucio and Latapí. Once M. leprae has entered the endothelial cell, the micro-organism damages the blood vessels, leading to the specific changes seen in this variety of lepromatous leprosy.

Analysis of 6000 skin biopsies of the national leprosy control program in Mexico.

Six thousand skin biopsy specimens taken from April 1978 to January 2002 under conditions as specified by the National Leprosy Control Program (NLCP), were analyzed to obtain information about the work of the program and contribute to the knowledge of this illness in the Mexico. Six-thousand request forms for histologic exam of the NLCP were reviewed. Sixty-two percent of the requests had all the required information and in 38% one or more data items were omitted. The age range was 2 to 98 yrs with a median of 50 yrs; a small number of cases was observed in the age group of 0 to 14 yrs, and the peak was in the age group of 41 to 50 yrs. Of the 6000 biopsies, 3693 were classified. Polar lepromatous (LL) was the most common form of the disease, in 60.3% of cases. Twice as many cases were multibacillary leprosy (MB) as paucibacillary (PB). MB predominated in males, and PB predominated in females. The Cohen's kappa index (kappa) of clinical-histological agreement was 0.202 (95% CI 0.184-0.219) and showed a poor grade of agreement between clinical and histologic diagnosis, with a level of significance of 0.05 (p <0.001). The results may indicate the end of leprosy in Mexico, a country in which the national goal of elimination was reached in 1994, with a prevalence since the year 2000 of 0.17/10 000.

La reacción del ácido peryódico Sciff más dimetilsulfóxido para el diagnóstico de micosis superficiales y de eritrasma en raspaduras de la piel y de las uñas / PAS plus DMSO stain for rapid diagnosis of superficial fungal infections and erythrasma

La tinción del PAS más DMSO, es un método sencillo y rápido mediante el cual las raspaduras de lesiones de la piel o de la uñas, recogidas con una laminilla a la que se le ha aplicado albúmina de Mayer en su superficie, puede examinarse microscópicamente y determinar con precisión la ausencia o presencia de hongos y de Corynebacterium minutissimum. El método, además, permite obtener preparaciones permanentes

Histoplasmosis / Histoplasmosis

Se hace una descripción de la histoplasmosis que incluye patogenia, cuadro clínico, patología, serología, diagnóstico, tratamiento y prevención. El artículo está basado en la experiencia obtenida en el Insituto de Salubridad y Enfermedades Tropicales de la Secretaría de Salud de México