Brote de histoplasmosis en la Escuela de Cadetes de la Base Aérea de Morón, Provincia de Buenos Aires, República Argentina / Histoplasmosis outbreak in Morón, Buenos Aires Province, Argentina

Se describe un brote de histoplasmosis que afectó a 6 cadetes de la Fuerza Aérea Argentina, sin antecedentes patológicos previos. Todos consultaron por problemas respiratorios después de haber limpiado un hangar. En ese recinto se encontraron abundantes deyecciones de animales, presuntamente de palomas y murciélagos. Los pacientes sufrieron fiebre, mialgias, taquipnea y tos no productiva. Las radiografías y tomografías de tórax mostraron imágenes pulmonares micronodulares, engrosamiento de los tabiques interalveolares y adenopatías hiliares. Todos tuvieron una evolución favorable y no requirieron tratamiento antifúngico. Las pruebas de inmunodifusión y contrainmunoelectroforesis con antígenos de Histoplasma capsulatum fueron positivas, al igual que las intradermorreacciones con histoplasmina. Se recogieron 5 muestras de tierra del lugar, las que fueron inoculadas por vía intraperitoneal a 20 hámsteres. De los cultivos de hígado y bazo de dichos animales se consiguió aislar la fase micelial de H. capsulatum. La cepa aislada se comparó con las obtenidas de 12 pacientes argentinos utilizando perfiles genéticos y se observó un clado único con más de 96% de similitud, lo que confirma la homogeneidad de las cepas argentinas. Si bien la histoplasmosis es endémica en la Pampa húmeda, este es el primer brote totalmente documentado al sur del paralelo 34°.

An histoplasmosis outbreak affecting 6 previously healthy Air Force cadets is herein presented. The patients suffered from fever and respiratory symptoms after having cleaned an abandoned hangar soiled with pigeons and bat droppings. They all presented fever, myalgia, tachypnea, and nonproductive cough. Chest X-ray and CT scan studies showed disseminated reticulonodular images affecting both lungs. Hiliar adenomegalies were also observed. All patients achieved a favourable outcome without antifungal treatment. Both serologic tests searching for specificic antibodies (immunodiffusion and counterimmunoelectrophoresis) and histoplasmin skin tests were positive in all cases. Five soil samples mixed with pigeons and bat droppings were collected from the hangar. Suspensions of these samples were inoculated into 20 hamsters by intraperitoneal injection; mycelial phase of H. capsulatum was isolated from liver and spleen cultures. The genetic profile of this strain was compared with 12 isolates obtained from Argentinean patients, and a great degree of homogeneity was observed (> 96% similarity). Although histoplasmosis is endemic in the wet Pampas, this is the first epidemic outbreak reported south of the 34th parallel.

La coccidioidomicosis en Argentina, 1892-2009 / Coccidioidomycosis in Argentina, 1892-2009

Los casos clínicos de coccidioidomicosis en Argentina son pocos y han tenido lugar fundamentalmente en la extensa región árida precordillerana. Este trabajo tiene como objetivos realizar una revisión retrospectiva del total de casos de coccidioidomicosis documentados en Argentina desde el año 1892 hasta 2009 y describir una serie de casos ocurridos en los últimos 4 años. En 117 años se documentaron 128 casos. Desde la primera descripción de la enfermedad en 1892 hasta 1939 se registraron 6 casos; desde 1940 hasta 1999, 59 casos (6-14 casos cada 10 años); y los 63 casos restantes (49% del total histórico) se produjeron en el último decenio. La mediana de edad de los 34 pacientes registrados en el período 2006-2009 fue de 31 años (rango: 7-89), la relación hombre:mujer fue 1,3:1; 12 de estos individuos eran inmunocomprometidos. Veintiséis casos se confirmaron por examen microscópico, por cultivo o por ambos procedimientos; los casos restantes se confirmaron por serología. Todos los aislamientos recuperados fueron identificados como Coccidioides posadasii. Treinta pacientes residían en una amplia área geográfica con epicentro en el valle de Catamarca. Entre 2006 y 2009, la tasa de incidencia en la provincia de Catamarca se incrementó desde valores históricos inferiores a 0,5 casos cada 100 000 habitantes hasta 2,0 casos cada 100 000 habitantes. Este aumento sugiere una emergencia de la coccidioidomicosis en el área.

Clinical cases of coccidioidomycosis are rare in Argentina and are generally found in the large arid precordilleran area of the country. This study aims to perform a retrospective review of all coccidioidomycosis cases documented in the country from 1892 to 2009, and to describe those occurring in the last 4 years. One hundred and twenty eight cases were documented in the 117 year-period. Since the original description of the disease in 1892 until 1939, only 6 cases were registered; between 1940 and 1999, 59 (6-14/10 yrs) and the remaining 63 (49% of total cases) occurred in the last decade. The median age of 34 patients registered in 2006-2009 was 31 years (range: 7-89), male/female ratio was 1.3:1 and 12 patients were immunocompromised. Twenty-six cases were confirmed by direct microscopy and/or culture whereas the remaining ones by serology. All isolates were identified as Coccidioides posadasii. Thirty patients lived in a vast geographic region with epicenter in Catamarca Valley. Between 2006 and 2009, annual disease incidence rates in Catamarca Province increased from historical values below 0.5/100,000 to 2/100,000 inhabitants. Such increase suggests an emergency of coccidioidomycosis in that region.

[Histoplasmosis outbreak in Morón, Buenos Aires Province, Argentina]. / Brote de histoplasmosis en la Escuela de Cadetes de la Base Aérea de Morón, Provincia de Buenos Aires, República Argentina.

A histoplasmosis outbreak affecting 6 previously healthy Air Force cadets is herein presented. The patients suffered from fever and respiratory symptoms after having cleaned an abandoned hangar soiled with pigeons and bat droppings. They all presented fever, myalgia, tachypnea, and nonproductive cough. Chest X-ray and CT scan studies showed disseminated reticulonodular images affecting both lungs. Hiliar adenomegalies were also observed. All patients achieved a favourable outcome without antifungal treatment. Both serologic tests searching for specificic antibodies (immunodiffusion and counterimmunoelectrophoresis) and histoplasmin skin tests were positive in all cases. Five soil samples mixed with pigeons and bat droppings were collected from the hangar. Suspensions of these samples were inoculated into 20 hamsters by intraperitoneal injection; mycelial phase of H. capsulatum was isolated from liver and spleen cultures. The genetic profile of this strain was compared with 12 isolates obtained from Argentinean patients, and a great degree of homogeneity was observed (> 96% similarity). Although histoplasmosis is endemic in the wet Pampas, this is the first epidemic outbreak reported south of the 34th parallel.

[Coccidioidomycosis in Argentina, 1892-2009]. / La coccidioidomicosis en Argentina, 1892-2009.

Clinical cases of coccidioidomycosis are rare in Argentina and are generally found in the large arid precordilleran area of the country. This study aims to perform a retrospective review of all coccidioidomycosis cases documented in the country from 1892 to 2009, and to describe those occurring in the last 4 years. One hundred and twenty eight cases were documented in the 117 year-period. Since the original description of the disease in 1892 until 1939, only 6 cases were registered; between 1940 and 1999, 59 (6-14/10 yrs) and the remaining 63 (49% of total cases) occurred in the last decade. The median age of 34 patients registered in 2006-2009 was 31 years (range: 7-89), male/female ratio was 1.3:1 and 12 patients were immunocompromised. Twenty-six cases were confirmed by direct microscopy and/or culture whereas the remaining ones by serology. All isolates were identified as Coccidioides posadasii. Thirty patients lived in a vast geographic region with epicenter in Catamarca Valley. Between 2006 and 2009, annual disease incidence rates in Catamarca Province increased from historical values below 0.5/100,000 to 2/100,000 inhabitants. Such increase suggests an emergency of coccidioidomycosis in that region.

[Molecular diagnosis of human histoplasmosis in whole blood samples]. / Diagnóstico molecular de histoplasmosis humana en muestras de sangre entera.

To assess the value of using whole blood samples for the molecular diagnosis of histoplasmosis, we applied an in-house DNA extraction method and a nested PCR targeting a 210 bp specific segment of the Histoplasma capsulatum HcP100 gene. A whole blood volume of 2.5-3 milliliters was centrifuged and the cellular pellet was treated with Trichoderma harzianum lyticase and proteinase K prior to applying a conventional phenol DNA extraction. This procedure allowed complete cell lysis, high DNA yield and specific amplification. The PCR detection limit was 0.25-1 yeast cells/ml of blood sample. The method was assessed on 31 blood samples from 19 patients with microbiological diagnosis of histoplasmosis, 30 healthy persons and 21 patients with other mycoses or mycobacterial diseases. Positive results were obtained in samples from 17/19 patients with histoplasmosis (14/15 immunocompromised and 3/4 without known immunological disorder). Blood samples from the 30 healthy controls and 20 patients with other conditions proved negative; the only false positive result was obtained from a patient with Mycobacterium avium-intracellulare infection. With 89% sensitivity and 98% specificity, this molecular method for detection of the agent in blood shows promising for the rapid diagnosis of human histoplasmosis.

Diagnóstico molecular de histoplasmosis humana en muestras de sangre entera / Molecular diagnosis of human histoplasmosis in whole blood samples

Se evaluó el uso de sangre entera para el diagnóstico molecular de histoplasmosis utilizando un método artesanal de extracción de ADN fúngico y una PCR anidada que amplifica una porción del gen HcP100 específica de Histoplasma capsulatum. La sangre entera se trató con liticasa, enzima lisante de Trichoderma harzianum y proteinasa K, seguido de una extracción fenólica. Este tratamiento permitió una lisis completa de las células, mostró buen rendimiento en la obtención de ADN y posibilitó la detección de la banda de 210 pb específica de H. capsulatum en la PCR anidada. El límite de detección fue de 0,25-1 levaduras/ml de sangre. El método se evaluó en 31 muestras de sangre de 19 pacientes con diagnóstico microbiológico de histoplasmosis, en 21 muestras de pacientes con otras micosis o infecciones por micobacterias y en 30 controles sanos. La PCR fue positiva en sangre para 17/19 pacientes con histoplasmosis (14/15 inmunocomprometidos y 3/4 sin inmunocompromiso aparente). Las muestras de sangre de los 30 controles sanos y de 20 pacientes con otras patologías fueron negativas, sólo hubo un falso positivo correspondiente a un paciente con infección por Mycobacterium avium-intracellulare. El método presentó 89% de sensibilidad y 96% de especificidad para el diagnóstico de histoplasmosis en sangre entera.

To assess the value of using whole blood samples for the molecular diagnosis of histoplasmosis, we applied an in-house DNA extraction method and a nested PCR targeting a 210 bp specific segment of the Histoplasma capsulatum HcP100 gene. A whole blood volume of 2.5-3 milliliters was centrifuged and the cellular pellet was treated with Trichoderma harzianum lyticase and proteinase K prior to applying a conventional phenol DNA extraction. This procedure allowed complete cell lysis, high DNA yield and specific amplification. The PCR detection limit was 0.25-1 yeast cells/ml of blood sample. The method was assessed on 31 blood samples from 19 patients with microbiological diagnosis of histoplasmosis, 30 healthy persons and 21 patients with other mycoses or mycobacterial diseases. Positive results were obtained in samples from 17/19 patients with histoplasmosis (14/15 immunocompromised and 3/4 without known immunological disorder). Blood samples from the 30 healthy controls and 20 patients with other conditions proved negative; the only false positive result was obtained from a patient with Mycobacterium avium-intracellulare infection. With 89% sensitivity and 98% specificity, this molecular method for detection of the agent in blood shows promising for the rapid diagnosis of human histoplasmosis.