Giemsa and Grocott in the recognition of Histoplasma capsulatum in blood smears.

OBJECTIVE: To facilitate the recognition of intracellular yeasts of Histoplasma capsulatum and differentiate it from Leishmania amastigotes and other parasites, using the combination of Giemsa and a rapid modification of Grocott stains to peripheral blood smears in a hematological study. METHODS: The combination of both stains was applied consecutively (first Grocott and then Giemsa) to previously fixed peripheral blood smears. Microscopy was performed with 400× and 1 000×, the latter using immersion oil. RESULTS: The yeasts of Histoplasma capsulatum were observed into the cytoplasm of leukocytes as brownish oval elements, with 3-4 µm in diameter. CONCLUSIONS: The combination of both techniques is a simple and fast method to facilitate recognition of intracellular yeasts and it is different from intracellular parasitic elements. Moreover, it allows distinguishing the cell elements that are in the microscopic preparations. It may be very helpful in those cases in which the presumptive diagnosis of histoplasmosis has not been established yet and where other more sophisticated methods are not available.

Rapid and biosecure diagnostic test for tuberculosis.

Early and rapid detection of the causative organism is necessary in tuberculosis. We present here an integrated and dedicated molecular biology system for tuberculosis diagnosis. One hundred and eighty-nine (189) biologic specimens from patients strongly suspected by clinical parameters of tuberculosis were studied by Ziehl-Neelsen staining, cultivation on a solid medium, and by a balanced heminested fluorometric PCR system (Orange G3TB) that preserves worker safety and produces a rather pure material free of potential inhibitors. DNA amplification was carried out in a low cost using a tuberculosis thermocycler-fluorometer. The double stranded DNA produced is fluorometrically detected. The whole reaction is carried out in one single tube which is never opened after adding the processed sample, thus minimizing the risk of cross contamination with amplicons. The assay is able to detect 30 bacilli/ml of sample having a 99.8 % inter-assay coefficient of variation. PCR was positive in 36 (18.9 %) tested samples (33 of them were smear-negative). In our study, it yields a preliminary overall sensitivity of 97.4 %. In addition, its overall specificity is 98.7 %. The total run time of the test is 4 h with two and a half real working hours. All PCR-positive samples also had a positive result by microbiological culture and clinical criteria. The results obtained showed that it could be a very useful tool to increase efficiency in detecting the tuberculosis disease in low bacillus inoculum samples. Furthermore, its low cost and friendly usage make it feasible to be used in regions with poor development.

Infections and inequalities: anemia in AIDS, the disadvantages of poverty.

OBJECTIVE: To study anemia in AIDS patients and its relation with socioeconomic, employment status and educational levels. METHODS: A total number of 442 patients who visited the Infectious Diseases University Hospital in Buenos Aires, Argentina were included in the study. Patients were dividied into two groups, i.e. one with anemia and the other without anemia. Anemia epidemiology and its relationship with educational level, housing, job situation, monthly income, total daily caloric intake and weekly intake of meat were evaluated. RESULTS: Anemia was found in 228 patients (54%). Comparing patients with or without anemia, a statistically significant difference was found (P<0.000 1) in those whose highest educational level reached was primary school, who lived in a precarious home, who had no stable job or were unable to work, whose income was less than 30 dollars per month, whose meat consumption was less than twice a week or received less than 8 000 calories per day. CONCLUSIONS: The high prevalence of anemia found in poor patients with AIDS suggests that poverty increases the risk to suffer from this hematological complication. The relationship between economic development policies and AIDS is complex. Our results seem to point to the fact that AIDS epidemic may affect economic development and in turn be affected by it. If we consider that AIDS affects the economically active adult population, despite recent medical progress it usually brings about fatal consequences, especially within the poorest sectors of society where the disease reduces the average life expectancy, increases health care demand and tends to exacerbate poverty and iniquity.

A case report of cutaneous larva migrans in Argentina.

Cutaneous larva migrans (CLM) represents the most common tropically acquired dermatosis. CLM is caused by infection with hookworm larvae in tropical and sub-tropical areas, and people who have a history of foreign travel and of walking barefoot on sandy soil or beaches are at a high risk of getting infected with it. The diagnosis is usually made on the basis of the typical appearance of the lesion, intense itching and history of foreign travel. CLM is a common parasitic skin disease that can be easily prevented by wearing 'protective' footwear. A case of CLM is described in this article.

Diagnosis of Mycobacterium tuberculosis using molecular biology technology.

OBJECTIVE: To present an integrated molecular biology dedicated system for tuberculosis diagnosis. METHODS: One hundred and five sputum specimens from patients strongly suspected by clinical parameters of tuberculosis were studied by Ziehl-Neelsen staining, by cultivation on solid medium and by a balanced heminested fluorometric PCR system (Orange G3TB) that could preserve worker safety and produce a rather pure material free of potential inhibitors. DNA amplification was performed in a low cost tuberculosis termocycler-fluorometer. Produced double stranded DNA was flurometrically detected. The whole reaction was conducted in one single tube which would not be opened after adding the processed sample in order to minimize the risk of cross contamination with amplicons. RESULTS: The assay was able to detect 30 bacillus per sample mL with 99.8% interassay variation coefficient. PCR was positive in 23 (21.9%) tested samples (21 of them were smear negative). In our study it showed a preliminary sensitivity of 94.5% for sputum and an overall specificity of 98.7%. CONCLUSIONS: Total run time of the test is 4 h with 2.5 real working time. All PCR positive samples are also positive by microbiological culture and clinical criteria. Results show that it could be a very useful tool to increase detection efficiency of tuberculosis disease in low bacilus load samples. Furthermore, its low cost and friendly using make it feasible to run in poor regions.

Enfermedades transmitidas por los alimentos: Análisis del riesgo microbiológico / Risk analysis of foodborne diseases: Microbial risk assessment

The basic goals of risk assessment include the following: to identify potentially hazardous situations and apply appropriate methods to estimate the likelihood that a hazard occurs. In The uncertainty in that estimate, to provide alternative solutions to reduce the risk, estimate the effectiveness of those solutions, provide information to base a risk management decision, and estimate the uncertainty associated with the analysis. Risk analysis provides the rational framework for assembling and then analysing the evidence relating to risk and presenting the results in a form that is easy to understand and then act upon fairly and effectively. Progress made is no excuse for arrogance. The present review is definitely not designed as the last word on risk analysis for foodborne diseases. Rather, this review has been designed to continue an evolving and necessary process and to provide a reference point that indicates the state of development in 2010.

Las metas básicas del análisis de riesgo incluyen las siguientes: identificar las situaciones potencialmente peligrosas, aplicar los métodos apropiados para estimar la probabilidad que un peligro ocurra, y en la incertidumbre en esa estimación, proporcionar las soluciones alternativas para reducir el riesgo, estimar la eficacia de esas soluciones, proporcionar la información sobre las que se base una decisión de la gestión de riesgos, y estimar la incertidumbre asociada a la evaluación. El análisis de riesgos constituye un sistema de referencia coherente para reunir y analizar indicios sobre los factores de riesgo, y también para presentar los resultados de modo inteligible y obrar después eficazmente. Pero los progresos realizados no pueden excusar la arrogancia. La presente revisión no pretende sentar cátedra sobre el análisis de riesgo microbiano, más bien está pensado como una etapa más de un proceso necesario y permanente, como un jalón que describe el estado de cosas en 2010.

Diagnóstico de criptococosis a partir de lesiones cutáneas / Diagnosis of cryptococcosis in cutaneous lesions

Se realizó el diagnóstico de criptococosis en un paciente con lesiones cutáneas de aspecto moluscoide, presentes en gran número en el rostro, sospechadas clínicamente de ser provocadas por Histoplasma capsulatum. El paciente, posteriormente diagnosticado como VIH positivo, presentó además Cryptococcus neoformans en el LCR y fue tratado con anfotericina B endovenosa. Con material obtenido por escarificación de las lesiones se realizaron extendidos y practicaron cultivos. Aplicadas a los extendidos, las coloraciones de Giemsa, Grocott y mucicarmín de Mayer, permitieron la observación de levaduras redondas y capsuladas que en los cultivos en agar semillas de girasol desarrollaron colonias de color pardo que correspondieron a Cryptococcus neoformans.

Diagnosis of cryptococcosis was performed in a patient with multiple cutaneous Muluscum contagiosumlike lesions in the face, clinically suspected as produced by Histoplasma capsulatum. The patient, after being diagnosed HIV positive, also showed Cryptococcus neoformans in the CSF, and was treated with intravenous amphotericin B. Clinical samples from the skin lesions were obtained and smears stained by Giemsa, Grocott and Mayer's mucicarmin were performed. Part of these samples, obtained by scrapping the ulcers, were suspended in isotonic saline solution and cultivated in Sabouraud dextrose agar and sunfloweragar; Cryptococcus neoformans colonies were identified.

[Risk analysis of foodborne diseases: microbial risk assessment]. / Enfermedades transmitidas por los alimentos: Análisis del riesgo microbiológico.

The basic goals of risk assessment include the following: to identify potentially hazardous situations and apply appropriate methods to estimate the likelihood that a hazard occurs. In The uncertainty in that estimate, to provide alternative solutions to reduce the risk, estimate the effectiveness of those solutions, provide information to base a risk management decision, and estimate the uncertainty associated with the analysis. Risk analysis provides the rational framework for assembling and then analysing the evidence relating to risk and presenting the results in a form that is easy to understand and then act upon fairly and effectively. Progress made is no excuse for arrogance. The present review is definitely not designed as the last word on risk analysis for foodborne diseases. Rather, this review has been designed to continue an evolving and necessary process and to provide a reference point that indicates the state of development in 2010.

Amenaza del virus Chikungunya: la globalización de las enfermedades transmitidas por insecto vector / The Chikungunya threat: the globalization of vectorborne diseases

El brote de infección Chikungunya (CHIKV) que se produjo en el verano de 2007 en una zona templada del norte de Italia, constituye un nuevo modelo para la difusión de una enfermedad tropical fuera de los lugares convencionales, esta situación ha sido causada principalmente, por la peligrosa mezcla de la gran población de un competente vector, el mosquito tigre de Asia, y la posibilidad de que una persona regrese de la zona de la difusión normal de CHIKV durante la fase de viremia asintomática. Teniendo en cuenta las dificultades para controlar la propagación de Aedes albopictus y el gran número de personas que viajan hacia y desde los ámbitos de la difusión normal de las enfermedades transmitidas por vectores tropicales, pensamos que la epidemia de 2007 podría ser sólo la primera de una serie de posibles brotes. En conclusión, esta epidemia urbana de la infección CHIKV en un país templado, determina una nueva perspectiva en la preparación para las inesperadas infecciones emergentes por el virus, las que deben ser afrontadas mediante una estrategia combinada de difusión de vigilancia de vectores, y el diagnóstico inmediato de cualquier caso sospechoso de importación transmitido por vectores de enfermedades exóticas.

The outbreak of CHIKV infection that occurred in summer 2007 in a temperate area of northern Italy constitues a new model for the diffusion of a tropical disease outside the conventional locations; this situation has been caused mainly by the dangerous mixture of the large population of a highly competent vector, the Asian tiger mosquito, and the possibility that an individual comes back from the area of normal diffusion of CHIKV during the asymptomatic viremic stage. Considering the difficulties in controlling the spread of Aedes albopictus and the large number of people travelling to and from the areas of normal diffusion of vector-borne tropical diseases, we think that the 2007 epidemic could be only the first of a possible series of these aoutbreaks. In conclusion, this urban epidemic of CHIKV infection in a temperate country determines a new perspective in the preparedness to unexpected emerging virus infections that must be faced by using a combined strategy of vector diffusion monitoring and immediate diagnosis of any suspected cases of imported vector-borne exotic disease.

[Radiation on the dining table]. / La radiación a la mesa.

Zero tolerance to bacterial contamination means considering the acceptance of "radiation on the table". The process of food irradiation has been extensively studied, nevertheless its use remains a matter of some controversy. Despite unanimous agreement within the medical community of the safety of this procedure, occasional concerns arise from the consumers. A common consumer misconception is that irradiation may turn the food "radioactive". A significant number of scientific studies on the topic were analyzed. We found no scientific study demonstrating that consumption of irradiated food might pose a risk to consumers. All studies conclude that food irradiation at the appropriate dose required to reduce contamination is safe and does not affect its nutritional value. In order to emphasize the issue we discuss the potential benefit vs harm of irradiation of food contaminated with E. coli 0157: H7. The association of this bacteria with severe disease and death has been clearly established in contrast with the lack of a demonstrated risk due to meat irradiation. We conclude that the risks of food irradiation remains "unknown" simply because, after four decades of research, none has been identified. In contrast to the risks of acquiring a food transmitted bacterial disease, the risk of irradiation is negligible.

Food-borne botulism in Argentina.

Botulism is a severe neuroparalytic disease caused by Clostridium botulinum toxins. Although the disease is uncommon it is a cause of great concern due to its high rate of mortality. Food-borne outbreaks of botulism occur worldwide and require immediate public health attention and acute care resources. Analysis of outbreaks showed that the food products most often involved were fermented fish products in Alaska; home-canned food, oil preservation and restaurant sauce in the rest of the United States (US) and in London and; and home-canned vegetables, airtight packed food with inappropriate refrigeration, and aerosols in Argentina. The diagnosis is based only on clinical findings matching the disease and previous exposure to suspicious food. Botulism must be immediately identified as even one case suggests the start of an epidemic and should be treated as a public health emergency. Therefore, the purpose of the following review is to recognize the risks associated with the consumption of potentially dangerous foods, and to encourage prevention by seeking to make all public health professionals aware of the dangers of this potentially lethal disease.

Dengue y fiebre hemorrágica dengue: su historia y su resurgimiento como problema de salud pública global: progresos y desafíos / Dengue and dengue haemorrhagic fever: its history and resurgence as a global public health problem: progress and challenges

El primer brote conocido de epidemias de dengue o enfermedad símil dengue ocurrió en 1779 y 1780 en Egipto e Indonesia y en 1780 en los EE.UU (Filadelfia). Está claro que el dengue y otros arbovirus con ecología similar han tenido una distribución extensa en zonas tropicales en los últimos 200 años. Históricamente, Asia ha sido el érea de endemicidad más alto, con los cuatro serotipos del virus dengue circulando en los grandes centros urbanos de la mayoría de los países...La Fiebre Hemorrágica por Dengue (FHD) y el Síndrome de Choque por Dengue (SCD), son las manifestaciones severas y/o fatales de la fiebre por dengue. Las epidemias de FHD/SCD ocurren sobre todo en países del sudeste asiático, donde afectan principalmente a los niños y se asocian con altas tasas de letalidad. El advenimiento del transporte aéreo comercial del jet en los años '60 promovió el mecanismo ideal para que el virus del dengue fuera transportado por las personas que habian visitado áreas endémicas y viajaban durante el período de incubación. La incidencia de dengue ha aumentado marcadamente desde los años '60, primero en Asia, luego en el Pacífico y las Américas y finalmente en Africa. Es notorio la mayor parte del mundo tropical, con una población estimada de 2,5 mil millones, está en peligro de la infección dengue...El uso de larvicidas y de insecticidas durante brotes tiene algunas limitaciones. Los esfuerzos ahora se están centrando en la educación sanitaria y la participación de la comunidad en un intento por controlar los vectores eliminando o reducienddo los sitios de cría. En la ausencia de una vacuna para protegerse de la infección dengue, la prevención y la contención de los brotes del dengue requerirán un control del vector con eficacia a largo plazo, con la participación de la comunidad y la vigilancia epidemiológica agresiva.

The first reported epidemics of dengue or dengue-like disease occurred in 1779 and 1780 in Egypt and Indonesia and in 1780 in the USA (Philadelphia). It is clear that dengue and other arboviruses with similar ecology had a widespread distribution in the tropics as long as 200 years ago. Historically, Asia has been the area of highest endemicity, with all four dengue serotypes circulating in the large urban centres in most countries... Dengue Hemorrhagic Fever (DHF) and Dengue Shock Syndrome (DSS) are the severe and/or fatal clinical manifestations of dengue fever. Epidemics of DHF/DSS occur mainly in the southeast Asian countries where children are seriously affected and high case-fatality ratio is annually reported. The advent of commercial jet air transport in the 1960s promoted the ideal mechanism for the carriage of dengue virus by persons who had visited endemic areas and were travelling during the incubation period. The incidence of dengue infection has increased markedly since the 1960s, first in Asia then in the Pacific and Americas and finally in Africa. It appears that most of the tropical world, with an estimated population of 2.5 billion, is at risk of infection with dengue...The use of larvicides and insecticides during aoutbreaks has some limitations. Efforts are now focusing on health education and community participation in an attempt to control the vector(s) by eliminating or reducing the breeding sites. In the absence of a dengue vaccine for public health use at present, prevention and containment of dengue autbreaks will require an effective long-term vector control with community participation and aggressive epidemiological surveillance.

La radiación a la mesa / Radiation on the dining table

Zero tolerance to bacterial contamination means considering the acceptance of "radiation on the table". The process of food irradiation has been extensively studied, nevertheless its use remains a matter of some controversy. Despite unanimous agreement within the medical community of the safety of this procedure, occasional concerns arise from the consumers. Acommon consumer misconception is that irradiationmay turn the food "radioactive". A significant number of scientific studies on the topic were analyzed. We found no scientific study demonstrating that consumption of irradiated food might pose a risk to consumers. All studies conclude that food irradiation at the appropriate dose required to reduce contamination is safe and does not affect its nutritional valué. In order to emphasize the issue we discuss the potential benefit vs harm of irradiation of food contaminated with E. coli 0157: H7. The association of this bacteria with severe disease and death has been clearly established in contrast with the lack of a demonstrated risk due to meat irradiation. We conclude that the risks of food irradiation remains "unknown" simply because, after four decades of research, none has been identified. In contrast to the risks of acquiring a food transmitted bacterial disease, the risk of irradiation is negligible.

Tolerancia cero a la contaminación bacteriana implica considerar la inclusión de "la radiación a la mesa". La irradiación es uno de los métodos de procesado de alimentos que se han estudiado de forma más extensa y estricta; sin embargo, su aplicación sigue siendo materia de discusión. Incluso si la inocuidad está bien establecida (hay acuerdo unánime entre la comunidad científica), de vez en cuando surgen preguntas de los consumidores. Es importante destacar que no hay ningún estudio científico consistente y reproducible, que demuestre o sugiera que el consumo de un alimento irradiado podría suponer un riesgo para la salud de los consumidores. Creemos que esta revisión es un aporte importante al conocimiento. Es necesario desmentir los errores generalizados sobre la irradiación, especialmente la idea de que los alimentos se tornan radioactivos. Se analizó una cantidad considerable de investigaciones científicas difundidas en publicaciones especializadas. De ellas surge que los alimentos irradiados con la dosis necesaria para alcanzar el objetivo mi-crobiológico deseado, se consideran inocuos y saludables para el consumo y adecuados desde un punto de vista nutricional. Para ser más claros, nadie pondría en duda que Escherichia coli 0157: H7 puede causar la muerte, la carne irradiada no. En definitiva, los riesgos de la irradiación de los alimentos son desconocidos, simplemente porque después de cuatro décadas de investigaciones, no se ha encontrado ninguno. Este es un argumento de suficiente peso, contra los riesgos conocidos de contraer una enfermedad bacteriana transmitida por alimentos.

Strongyloides stercoralis hyperinfection in a patient with AIDS.

Strongyloides stercoralis is a prevalent cause of severe infection and death in many areas of the world where fecal contamination of soil or water is common. The nematode is endemic in tropical and subtropical regions of the world, including northeastern Argentina, where infection rates may exceed 30% of the population. Strongyloides infections are often light and associated with few or no signs and symptoms, particularly during initial migration through the body. However, certain persons are at risk of severe, clinically significant disease developing. The manifestations of hyperinfection syndrome are divided, based on the system of origin, into intestinal and extraintestinal disease mainly involving the respiratory tract. Unfortunately, S stercoralis hyperinfection is seldom diagnosed until late in the course of the disease, which contributes to a high death rate. In patients with the hyperinfection syndrome and massive Strongyloides infection, adult respiratory distress syndrome with pulmonary insufficiency that requires intubation and mechanical ventilation may also develop. We report a case of S stercoralis hyperinfection in an HIV-infected patient, which resulted in death.