viernes, 29 de julio de 2016

Interim Guidance for Health Care Providers Caring for Pregnant Women with Possible #Zika Virus Exposure

CDC has updated its interim guidance for U.S. health care providers caring for pregnant women with possible Zika virus exposure, to include the emerging data indicating that Zika virus RNA can be detected for prolonged periods in some pregnant women. To increase the proportion of pregnant women with Zika virus infection who receive a definitive diagnosis, CDC recommends expanding real-time reverse transcription–polymerase chain reaction (rRT-PCR) testing. Possible exposures to Zika virus include travel to or residence in an area with active Zika virus transmission, or sex* with a partner who has traveled to or resides in an area with active Zika virus transmission without using condoms or other barrier methods to prevent infection.† Testing recommendations for pregnant women with possible Zika virus exposure who report clinical illness consistent with Zika virus disease§ (symptomatic pregnant women) are the same, regardless of their level of exposure (i.e., women with ongoing risk for possible exposure, including residence in or frequent travel to an area with active Zika virus transmission, as well as women living in areas without Zika virus transmission who travel to an area with active Zika virus transmission, or have unprotected sex with a partner who traveled to or resides in an area with active Zika virus transmission). Symptomatic pregnant women who are evaluated <2 weeks after symptom onset should receive serum and urine Zika virus rRT-PCR testing. Symptomatic pregnant women who are evaluated 2–12 weeks after symptom onset should first receive a Zika virus immunoglobulin (IgM) antibody test; if the IgM antibody test result is positive or equivocal, serum and urine rRT-PCR testing should be performed. Testing recommendations for pregnant women with possible Zika virus exposure who do not report clinical illness consistent with Zika virus disease (asymptomatic pregnant women) differ based on the circumstances of possible exposure. For asymptomatic pregnant women who live in areas without active Zika virus transmission and who are evaluated <2 weeks after last possible exposure, rRT-PCR testing should be performed. If the rRT-PCR result is negative, a Zika virus IgM antibody test should be performed 2–12 weeks after the exposure. Asymptomatic pregnant women who do not live in an area with active Zika virus transmission, who are first evaluated 2–12 weeks after their last possible exposure should first receive a Zika virus IgM antibody test; if the IgM antibody test result is positive or equivocal, serum and urine rRT-PCR should be performed. Asymptomatic pregnant women with ongoing risk for exposure to Zika virus should receive Zika virus IgM antibody testing as part of routine obstetric care during the first and second trimesters; immediate rRT-PCR testing should be performed when IgM antibody test results are positive or equivocal. This guidance also provides updated recommendations for the clinical management of pregnant women with confirmed or possible Zika virus infection. These recommendations will be updated when additional data become available.

REFERENCE:
Oduyebo T, et al. Update: Interim Guidance for Health Care Providers Caring for Pregnant Women with Possible Zika Virus Exposure — United States, July 2016. MMWR Morb Mortal Wkly Rep 2016;65:739–744. DOI: http://dx.doi.org/10.15585/mmwr.mm6529e1

Other:
Brooks JT, et al. Update: Interim Guidance for Prevention of Sexual Transmission of Zika Virus — United States, July 2016. MMWR Morb Mortal Wkly Rep 2016;65:745–747. DOI: http://dx.doi.org/10.15585/mmwr.mm6529e2
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jueves, 28 de julio de 2016

HISTORY 1951: Yellow fever and Max Theiler: the only Nobel Prize for a virus vaccine

Max Theiler receives the Nobel Prize in Physiology or
Medicine from the hands of  His Majesty the King Gustaf
Adolf VI on December 10, 1951. Photo provided by the
Karolinska Institutet.

In 1951, Max Theiler of the Rockefeller Foundation received the Nobel Prize in Physiology or Medicine for his discovery of an effective vaccine against yellow fever—a discovery first reported in the JEM 70 years ago. This was the first, and so far the only, Nobel Prize given for the development of a virus vaccine. Recently released Nobel archives now reveal how the advances in the yellow fever vaccine field were evaluated more than 50 years ago, and how this led to a prize for Max Theiler.

REFERENCE:
Norrby, Erling. “Yellow Fever and Max Theiler: The Only Nobel Prize for a Virus Vaccine.” The Journal of Experimental Medicine 204.12 (2007): 2779–2784. PMC. Web. 27 July 2016.
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miércoles, 20 de julio de 2016

Hipoclorito de sodio como agente desinfectante


Este artículo es sobre soluciones desinfectantes, siga el link para ver la >> desinfección de agua potable <<. 
Publicado originalmente el 19 de Julio de 2008.
El hipoclorito de sodio (NaOCl) es un compuesto oxidante de rápida acción utilizado a gran escala para la desinfección de superficies, desinfección de ropa hospitalaria y desechos, descontaminar salpicaduras de sangre, desinfección de equipos y mesas de trabajo resistentes a la oxidación, eliminación de olores y desinfección del agua. Los equipos o muebles metálicos tratados con cloro, tienden a oxidarse rápidamente en presencia de hipoclorito de sodio.
El hipoclorito de sodio es vendido en una solución clara de ligero color verde-amarillento y un olor característico. Como agente blanqueante de uso domestico normalmente contiene 5-6.5% de hipoclorito de sodio (con un pH de alrededor de 11, es irritante y corrosivo a los metales). Cuando el hipoclorito se conserva en su contenedor a temperatura ambiente y sin abrirlo, puede conservarse durante 1 mes, pero cuando se ha utilizado para preparar soluciones, se recomienda
 su cambio diario. Entre sus muchas propiedades incluyen su amplia y rápida actividad antimicrobiana, relativa estabilidad, fácil uso y bajo costo.
El hipoclorito es letal para varios microorganismos, virus y bacterias vegetativas, pero es menos efectivo contra esporas bacterianas, hongos y protozoarios. La actividad del hipoclorito se ve reducida en presencia de iones metálicos, biocapas, materiales orgánicos, bajo pH o luz UV. Las soluciones de trabajo deben ser preparadas diariamente. El cloro comercial que contiene 5-6%, que será utilizado para la desinfección de superficies, debe ser diluído 1:10 para obtener una concentración final de aproximadamente 0.5% de hipoclorito. Cuando se quiere desinfectar líquidos que pueden contener material orgánico, debe tenerse una concentración final de 1% de hipoclorito.
Gracias a su alta disponibilidad continua siendo de alto uso en hospitales. Pueden encontrar otras características y hojas de seguridad del hipoclorito de sodio. 

Antes de someter materiales o superficies a procesos de desinfección, es recomendable realizar un lavado con agua y jabón, para eliminar los materiales orgánicos presentes, que pueden interferir en la efectividad del hipoclorito de sodio. Antes de elegir un agente desinfectante, por favor revisa su efectividad para el microorganismo que te interesa.
Concentraciones recomendadas:

  • Venta al público: (Blanqueador casero, presentación comercial): 5-6 % (50-60 g/l, 50,000 ppm) de cloro libre
  • Para limpieza general, desinfección de manos, desinfección de ropa: 0.05% (500 mg/L; 500 ppm) *
  • Para desinfección general de áreas sin materia orgánica:  0.5% (5g/L;  5,000 ppm)
  • Para desinfección con material orgánico o derrames:  1 % (10 g/l, 10,000 ppm)
REVISAR LA ETIQUETA PARA VER LA CONCENTRACIÓN DE CLORO 
FÓRMULA PARA PREPARAR SOLUCIONES DESINFECTANTES
Cualquier concentración puede ser utilizada para obtener una solución de hipoclorito diluída utilizando la siguiente fórmula:  =>

Por ejemplo para preparar una solución 0.5% a partir de una 4.5% de hipoclorito de sodio se utilizarán 8 partes de agua con 1 parte de agua. 
Donde "parte" puede ser utilizado para cualquier unidad de medida (litro, mililitro, galones, etc), o utilizando cualquier medidor (taza, frasco, garrafón, etc). En paises de habla francesa, la cantidad de hipoclorito se expresa como "grados de cloro". Un grado de cloro = 0.3% de cloro activo. (Ref. 8)


Otra fórmula para calcular el volumen necesario para preparar el hipoclorito de sodio 0.5% a partir de una solución concentrada:



DESINFECCIÓN DE SÁBANAS Y ROPA DE CAMA 
Toda la ropa de cama que ha estado en contacto con pacientes puede estar contaminado con líquidos o fluidos corporales (orina, sangre, vómito). Cuando se manejan este tipo de ropa, debe utilizarse equipo de protección adecuado, pero debe incluirse, guantes, mascarillas, lentes de protección, batas y botas. Los excesos de excremento deberán retirarse y colocarse en bolsas para desechos. Antes de desinfectar, deberá realizarse un lavado en lavadora con agua y jabón. Enjuagar para eliminar el exceso de jabón. Finalmente, colocar las sábanas en una solución de hipoclorito de sodio al 0.05%, durante por lo menos 30 minutos ó una hora. Puede realizarse un segundo enjuague para eliminar el exceso de hipoclorito, y continuar con los procesos normales de secado. 
El lavado a mano debe evitarse en la medida de lo posible. Cuando por las condiciones, no puede utilizarse lavadoras automáticas, las sábanas deberán colocarse en un gran contenedor con agua caliente y jabón, y agitar en círculos con un palo o varilla. Eliminar el agua, y colocar una solución al 0.1% de hipoclorito de sodio por 15 minutos, sumergiendo completamente las sábanas. Enjuagar nuevamente y dejar secar, evitando sacudir en la medida de lo posible (Ver Ref. 8).

DESCARGAR AQUI TABLAS PARA PREPARAR HIPOCLORITO DE SODIO PARA LA DESINFECCIÓN 

Para la desinfección de líquidos que puedan contener microorganismos, debe prepararse una solución al 2% de hipoclorito de sodio. Posteriormente, mezclar en proporción 1:1 (1 volumen de desinfectante, 1 volumen de líquido). De esta forma, al final tendrá una concentración de 1%. Dejar reposar durante 30 minutos. Por ejemplo: 200 ml de orina + 200 ml de solución de hipoclorito de sodio al 2%.

Para desinfectar superficies o materiales de laboratorio (que no sean metálicos), que no contengan material orgánico, deberá usarse una solución de hipoclorito de sodio al 0.5%. Por ejemplo, para desinfectar gradillas de laboratorio de plástico, sumérjalas en la solución al 0.5% por al menos 30 minutos.


Sobre la inestabilidad del cloro:
Una vez preparadas, las soluciones guardadas a 25ºC, en recipientes cerrados, contenedores opacos, pierden 50% de su contenido de cloro libre en un periodo de 30 días. Una solución al 1%, tendrá solo 0.5% de cloro 30 días después de preparado. Las soluciones al 5% se degradan más lentamente si se almacenan en contenedores obscuros. A mayor temperatura y con mayor cantidad de luz que reciban, el proceso de degradación se acelera. 
Referencia: Guideline for disinfection and Sterlization in healthcares facilities, 2008.

Sobre la toxicidad del cloro:
El hipoclorito de sodio ocasiona:
  • Irritación ocular, orofaríngea, esofagial y quemaduras gástricas.
  • Corrosión a los metales 
  • Reacciona de forma tóxica con el amoniaco y ácidos (presente en los productos desinfectantes comunes), por lo que no deben hacerse mezclas de desinfectantes.
  • Producción de carcinógeno bis (clorometil) eter cuando se mezcla con formaldehído.
  • Producción de carcinógeno trihalometano cuando el agua es hiperclorinada (exceso de cloro).

Por favor visite esta página para ver las características y tratamiento de la intoxicación por cloro: https://medlineplus.gov/spanish/ency/article/002772.htm

Referencias:
  1. Rutala WA and Weber DJ. Uses of Inorganic Hypochlorite (Bleach) in Health-Care Facilities. Clinical Microbiological Reviews 1997; 10(4):597-610. PDF. 
  2. Enviromental Health and Safety. University of Kentucky. PDF.
  3. Uso de desinfectantes. Guías para la prevención, control y vigilancia epidemiológica de infecciones intrahospitalarias. Secretaría Distrital de Salud de Bogotá. PDF.
  4. Githui WA, Matu SW, Tunge N, Juma E. Biocidal effect of bleach on Mycobacterium tuberculosis: a safety measure. Int J Tuberc Lung Dis 2007. 11(7):798–802. PDF.
  5. Hojas de seguridad de microorganismos, con las recomendaciones de agentes desinfectantes.
  6. Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008. CDC.
  7. Intoxicación con hipoclorito de sodio
  8. How to make chlorine solutions for environmental disinfection (Annex 6 from Interim Infection Prevention and Control Guidance for Care of Patients with Suspected or Confirmed Filovirus Haemorrhagic Fever  in Health-Care Settings, with Focus on Ebola 2014)
  9. OSHA: Cleaning and Decontamination of #Ebola on Surfaces. Guidance for Workers and Employers in Non-Healthcare/Non-Laboratory Settings
  10. For General Healthcare Settings in West Africa: How to Prepare and Use Chlorine Solutions

lunes, 18 de julio de 2016

Marburg Virus Reverse Genetics Systems

The highly pathogenic Marburg virus (MARV) is a member of the Filoviridae family and belongs to the group of nonsegmented negative-strand RNA viruses. Reverse genetics systems established for MARV have been used to study various aspects of the viral replication cycle, analyze host responses, image viral infection, and screen for antivirals. This article provides an overview of the currently established MARV reverse genetic systems based on minigenomes, infectious virus-like particles and full-length clones, and the research that has been conducted using these systems.
Keywords: Marburg virus; Ebola virus; filoviruses; nonsegmented negative-sense RNA viruses; reverse genetics system; minigenome; full-length clones; virus-like particles; virus rescue; biosafety level 4
REFERENCE:
Schmidt KM, Mühlberger E. Marburg Virus Reverse Genetics Systems. Viruses. 2016 Jun 22;8(6).

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jueves, 14 de julio de 2016

Molecular epidemiology and phylogeny of Nipah virus infection: A mini review.

Nipah virus (NiV) is a member of the genus Henipavirus of the family Paramyxoviridae, characterized by high pathogenicity and endemic in South Asia. It is classified as a Biosafety Level-4 (BSL-4) agent. The case-fatality varies from 40% to 70% depending on the severity of the disease and on the availability of adequate healthcare facilities. At present no antiviral drugs are available for NiV disease and the treatment is just supportive. Phylogenetic and evolutionary analyses can be used to help in understanding the epidemiology and the temporal origin of this virus. This review provides an overview of evolutionary studies performed on Nipah viruses circulating in different countries. Thirty phylogenetic studies have been published from 2000 to 2015 years, searching on pub-med using the key words 'Nipah virus AND phylogeny' and twenty-eight molecular epidemiological studies from 2006 to 2015 have been performed, typing the key words 'Nipah virus AND molecular epidemiology'. Overall data from the published study demonstrated as phylogenetic and evolutionary analysis represent promising tools to evidence NiV epidemics, to study their origin and evolution and finally to act with effective preventive measure.

REFERENCE:
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lunes, 11 de julio de 2016

Use of RODAC plates to measure containment of Mycobacterium #tuberculosis in a Class IIB biosafety cabinet during routine operations.

OBJECTIVE/BACKGROUND: Guidelines for the manipulation of Mycobacterium tuberculosis (MTB) cultures require a Biosafety Level 3 (BSL-3) infrastructure and accompanying code of conduct. In this study, we aimed to validate and apply detection methods for viable mycobacteria from surfaces in a BSL-3 MTB laboratory.
METHODS: We evaluated phenotypic (Replicate Organism Detection and Counting [RODAC] plates) and molecular (propidium monoazide [PMA]-based polymerase chain reaction [PCR]) approaches for the detection of viable mycobacteria, as well as the effect of 70% ethanol applied for 5min for disinfection against mycobacteria. For validation of the method, recovery of serial dilutions of Mycobacterium bovis bacillus Calmette-Guérin from glass slides was measured. Subsequently, we stamped surfaces in and around the biosafety cabinet (BSC) after different technicians had manipulated high bacterial load suspensions for routine drug-susceptibility testing in a Class II BSC.
RESULTS: RODAC stamping could detect as few as three bacteria on slides stamped either 5min or 60min after inoculation. PMA-based PCR, tested in parallel, did not pass validation. Mycobacteria were still detected after 5-min disinfection with ethanol 70%. In the BSL-3, from 201 RODAC-stamped surfaces, MTB was detected in four: three inside a BSC-on a tube cap and on an operator's gloves-and one outside, on an operator's gown.
CONCLUSION: RODAC plates detect mycobacteria at low numbers of microorganisms. In addition, this method allowed us to show that 70% ethanol does not reliably kill mycobacteria when applied for 5min to a dried surface, and that MTB bacilli may arrive outside a Class II BSC during routine practice, although the route could not be documented.
KEYWORDS: Biosafety; Environmental sampling; Ethanol; Propidium monoazide; Replicate Organism Detection and Counting; Tuberculosis
REFERENCE:
Daneau G, et al. Use of RODAC plates to measure containment of Mycobacterium tuberculosis in a Class IIB biosafety cabinet during routine operations. Int J Mycobacteriol. 2016 Jun;5(2):148-54.

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jueves, 7 de julio de 2016

#CRISPR, the disruptor

By  Heidi Ledford
A powerful gene-editing technology is the biggest game changer to hit biology since PCR. But with its huge potential come pressing concerns.
By and large, researchers see these gaps as a minor price to pay for a powerful technique. But Doudna has begun to have more serious concerns about safety. Her worries began at a meeting in 2014, when she saw a postdoc present work in which a virus was engineered to carry the CRISPR components into mice. The mice breathed in the virus, allowing the CRISPR system to engineer mutations and create a model for human lung cancer4. Doudna got a chill; a minor mistake in the design of the guide RNA could result in a CRISPR that worked in human lungs as well. “It seemed incredibly scary that you might have students who were working with such a thing,” she says. “It's important for people to appreciate what this technology can do.”

REFERENCE:
Nature 522, 20–24 (04 June 2015) doi:10.1038/522020a


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martes, 5 de julio de 2016

Inactivation and Environmental Stability of #Zika Virus

Working with Zika virus, a Biosafety Level 2 (BSL-2) pathogen in the European Union, except for the United Kingdom (where it is BSL-3), requires specific safety precautions. No inactivation data specific for Zika virus are available; consequently, disinfection guidelines are based on protocols to inactivate other flaviviruses. To gain experimental evidence regarding inactivation and disinfection for Zika virus, we determined its susceptibility to various disinfectants and inactivation methods.

REFERENCES:


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lunes, 4 de julio de 2016

Precauciones para trabajadores de la salud contra la exposición a virus #Zika, en salas de parto

Los CDC recomiendan tomar precauciones estándar en todos los entornos de atención médica para evitar que el personal y los pacientes se infecten con el virus del Zika y patógenos a través de la sangre (por ej., el virus de la inmunodeficiencia humana [VIH] y el virus de la hepatitis C [VHC]). Debido al riesgo de exposición a grandes cantidades de líquidos corporales durante el trabajo de parto y a la naturaleza impredecible y apresurada de la atención obstétrica, es fundamental tomar medidas de precaución estándar en dichos entornos para evitar la transmisión del virus del Zika de pacientes infectados al personal de atención médica.

REFERENCIAS:

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