[New method for determining endemic levels]. / Nuevo método para elaborar corredores endémicos.

OBJECTIVE: Design an instrument for determining endemic levels or ranges using simple calculations; identify and estimate the parameters related to the dynamic transmission of communicable diseases. METHODS: The parameters for establishing a theoretical curve of expected incidence based on the logistic growth model were identified. The parameters were estimated by nonlinear regression based on the cumulative incidence data from the previous five years. The weekly cumulative incidence of cases of influenza-like illness in Argentina in 2009 was used as an example. It was compared to the 2004-2008 case series in order to determine the cumulative and non-cumulative endemic levels. RESULTS: According to the cumulative endemic levels identified, the country entered the outbreak area in week 2. The data from previous years showed that the maximum expected number of cases or carrying capacity (K) was 1 090 660. When the non-cumulative levels were considered, the outbreak was present in 34 out of 51 weeks. A range of 1.05 to 1.13 was estimated for the basic reproductive rate (R0) in the non-epidemic period from 2004-2008. CONCLUSIONS: The new method facilitated the determination of endemic levels using a simple procedure with the identification of parameters that are important for transmission. Although it has limitations such as the fact that the equation used is more appropriate for evaluating diseases with a pronounced annual cycle and less accurate for cycles of less than 1 year, it can be considered a valuable alternative method for determining endemic ranges and a new contribution to the study of epidemic outbreaks at local health surveillance levels.

[Impact of school closings on the influenza A (H1N1) outbreak in Tierra del Fuego, Argentina]. / Efecto del cierre de las escuelas sobre el brote de influenza A H1N1 en Tierra del Fuego, Argentina.

The impact of school closings on reducing the number of cases of influenza-like illness during an outbreak of influenza A (H1N1), which reached pandemic proportions, was assessed, along with other control measures, in the two main cities of Tierra del Fuego Province in southern Argentina. The incidence before and after the school closings in 2009 was compared by means of the t-test for related samples. By week 40, 6 901 cases of influenza-like illness had been detected, 281 of which were confirmed as influenza A (H1N1) through laboratory tests; 38 patients were hospitalized. After the intervention, there were nearly 10 times fewer cases than the average recorded in the health centers. The results indicate that closing schools during the influenza A (H1N1) outbreak resulted in a significantly lower incidence of influenza-like illness. However, the impact of other measures, such as case management and protection against exposure, should not be ignored. Timely implementation of this intervention, together with other measures, can help minimize the spread of influenza outbreaks.

Impact of the International Nosocomial Infection Control Consortium (INICC) multidimensional approach on rates of ventilator-associated pneumonia in intensive care units of two hospitals in Kuwait.

OBJECTIVE: To analyse the impact of the International Nosocomial Infection Control Consortium (INICC) multidimensional approach (IMA) on ventilator-associated pneumonia (VAP) rates in three intensive care units (ICUs) from two hospitals in Kuwait City from January 2014 to March 2015. DESIGN: A prospective, before-after study on 2507 adult ICU patients. During baseline, we performed outcome surveillance of VAP applying CDC/NHSN definitions. During intervention, we implemented the IMA through the INICC Surveillance Online System (ISOS), which included: (1) a bundle of infection prevention interventions; (2) education; (3) outcome surveillance; and (4) feedback on VAP rates and consequences. Logistic regression analysis was performed to estimate the effect of the intervention on VAP, controlling for potential bias. RESULTS: During baseline, 1990 mechanical ventilator (MV)-days and 14 VAPs were recorded, accounting for 7.0 VAPs per 1000 MV-days. During intervention, 9786 MV-days and 35 VAPs were recorded, accounting for 3.0 VAPs per 1000 MV-days. The VAP rate was reduced by 57.1% (incidence-density ratio = 0.51; 95% CI = 0.28-0.93; p = 0.042). Logistic regression showed a significant reduction in VAP rate during the intervention phase (OR = 0.39, 95% CI = 0.18-0.83), with 61% effectiveness. CONCLUSIONS: Implementing IMA through ISOS was associated with a significant reduction in the VAP rate in Kuwait ICUs.

Impact of the International Nosocomial Infection Control Consortium (INICC)'s Multidimensional Approach on Rates of Central Line-Associated Bloodstream Infection in 14 Intensive Care Units in 11 Hospitals of 5 Cities in Argentina.

OBJECTIVE To analyze the impact of the International Nosocomial Infection Control Consortium (INICC) Multidimensional Approach (IMA) and the INICC Surveillance Online System (ISOS) on central line-associated bloodstream infection (CLABSI) rates in 14 intensive care units (ICUs) in Argentina from January 2014 to April 2017. DESIGN This prospective, pre-post surveillance study of 3,940 ICU patients was conducted in 11 hospitals in 5 cities in Argentina. During our baseline evaluation, we performed outcome and process surveillance of CLABSI applying Centers for Disease Control and Prevention/National Health Safety Network (CDC/NHSN) definitions. During the intervention, we implemented the IMA through ISOS: (1) a bundle of infection prevention practice interventions, (2) education, (3) outcome surveillance, (4) process surveillance, (5) feedback on CLABSI rates and consequences, and (6) performance feedback of process surveillance. Bivariate and multivariate regression analyses were performed using a logistic regression model to estimate the effect of the intervention on the CLABSI rate. RESULTS During the baseline period, 5,118 CL days and 49 CLABSIs were recorded, for a rate of 9.6 CLABSIs per 1,000 central-line (CL) days. During the intervention, 15,659 CL days and 68 CLABSIs were recorded, for a rate of 4.1 CLABSIs per 1,000 CL days. The CLABSI rate was reduced by 57% (incidence density rate: 0.43; 95% confidence interval, 0.34-0.6; P<.001). CONCLUSIONS Implementing IMA through ISOS was associated with a significant reduction in the CLABSI rate in ICUs in Argentina. Infect Control Hosp Epidemiol 2018;39:445-451.

Impact of the International Nosocomial Infection Control Consortium's multidimensional approach on rates of ventilator-associated pneumonia in 14 intensive care units in 11 hospitals of 5 cities within Argentina.

BACKGROUND: To analyze the impact of the International Nosocomial Infection Control Consortium (INICC) multidimensional approach (IMA) on ventilator-associated pneumonia (VAP) rates in 11 hospitals within 5 cities of Argentina from January 2014-April 2017. METHODS: A multicenter, prospective, before-after surveillance study was conducted through the use of International Nosocomial Infection Control Consortium Surveillance Online System. During baseline, we performed outcome surveillance of VAP applying the definitions of the Centers for Disease Control andPrevention's National Healthcare Safety Network. During intervention, we implemented the IMA, which included a bundle of infection prevention practice interventions, education, outcome surveillance, process surveillance, feedback on VAP rates and consequences, and performance feedback of process surveillance. Bivariate and multivariate regression analyses were performed using a logistic regression model to estimate the effect of the intervention. RESULTS: We recorded 3,940 patients admitted to 14 intensive care units. At baseline, there were 19.9 VAPs per 1,000 mechanical ventilator (MV)-days-with 2,920 MV-days and 58 VAPs, which was reduced during intervention to 9.4 VAPs per 1,000 MV-days-with 9,261 MV-days and 103 VAPs. This accounted for a 52% rate reduction (incidence density rate, 0.48; 95% confidence interval, 0.3-0.7; P .001). CONCLUSIONS: Implementing the IMA was associated with significant reductions in VAP rates in intensive care units within Argentina.

Prospective multicentre study in intensive care units in five cities from the Kingdom of Saudi Arabia: Impact of the International Nosocomial Infection Control Consortium (INICC) multidimensional approach on rates of central line-associated bloodstream infection.

OBJECTIVE: To analyse the impact of the International Nosocomial Infection Control Consortium (INICC) Multidimensional Approach (IMA) and INICC Surveillance Online System (ISOS) on central line-associated bloodstream infection (CLABSI) rates in five intensive care units (ICUs) from October 2013 to September 2015. DESIGN: Prospective, before-after surveillance study of 3769 patients hospitalised in four adult ICUs and one paediatric ICU in five hospitals in five cities. During baseline, we performed outcome and process surveillance of CLABSI applying CDC/NHSN definitions. During intervention, we implemented IMA and ISOS, which included: (1) a bundle of infection prevention practice interventions; (2) education; (3) outcome surveillance; (4) process surveillance; (5) feedback on CLABSI rates and consequences; and (6) performance feedback of process surveillance. Bivariate and multivariate regression analyses were performed. RESULTS: During baseline, 4468 central line (CL) days and 31 CLABSIs were recorded, accounting for 6.9 CLABSIs per 1000 CL-days. During intervention, 12,027 CL-days and 37 CLABSIs were recorded, accounting for 3.1 CLABSIs per 1000 CL-days. The CLABSI rate was reduced by 56% (incidence-density rate, 0.44; 95% confidence interval, 0.28-0.72; P = 0.001). CONCLUSIONS: Implementing IMA through ISOS was associated with a significant reduction in the CLABSI rate in the ICUs of Saudi Arabia.

Cost-utility analysis of dengue vaccination in a country with heterogeneous risk of dengue transmission.

BACKGROUND: Dengue is one of the most important vector-borne diseases worldwide, and annually, nearly 390 million people are infected and 500,000 patients are hospitalized for severe dengue. Argentina has great variability in the risk of dengue transmission due to eco-climatic reasons. Currently no vaccines are available for dengue even though several vaccines are under development. OBJECTIVE: The aim of this study was to estimate the cost-effectiveness of a dengue vaccine in a country with heterogeneous risk of dengue transmission like Argentina. METHODS: The analysis was carried out from a societal perspective using a Markov model that included both vaccine and disease parameters. Utility was measured as disability adjusted life years (DALYs) averted, and the incremental cost-effectiveness ratio (ICER) of the vaccination was expressed in 2014 American dollars (US$) per DALY averted. One-way and probabilistic sensitivity analyses were performed to evaluate uncertainty in model outcomes, and a threshold analysis was conducted to estimate the highest possible price of the vaccine. RESULTS: The ICER of the vaccination program was found to be US$ 5714 per DALY averted. This value is lower than 3 times the per capita GDP of Argentina (US$ 38,619 in 2014); 54.9% of the simulations were below this value. If a vaccination program would be implemented the maximum vaccine price per dose has to be US$1.49 for a vaccination at national level or US$28.72 for a targeted vaccination in high transmission areas. CONCLUSIONS: These results demonstrate that vaccination against dengue would be cost-effective in Argentina, especially if carried out in predetermined regions at high risk of dengue transmission. However, these results should be interpreted with caution because the probabilistic sensitivity analysis showed that there was considerable uncertainty around the ICER value. The influence of variations in vaccine efficacy, cost and other important parameters are discussed in the text.

Multicenter study of device-associated infection rates in hospitals of Mongolia: Findings of the International Nosocomial Infection Control Consortium (INICC).

BACKGROUND: To report the results of the International Nosocomial Infection Control Consortium (INICC) multicenter study conducted in Mongolia from September 2013-March 2015. METHODS: A device-associated health care-associated infection prospective surveillance study in 3 adult intensive care units (ICUs) from 3 hospitals using the U.S. Centers for Disease Control and Prevention (CDC) and National Healthcare Safety Network (NHSN) definitions and INICC methods. RESULTS: We documented 467 ICU patients for 2,133 bed days. The central line-associated bloodstream infection (CLABSI) rate was 19.7 per 1,000 central line days, the ventilator-associated pneumonia (VAP) rate was 43.7 per 1,000 mechanical ventilator days, and the catheter-associated urinary tract infection (CAUTI) rate was 15.7 per 1,000 urinary catheter days; all of the rates are higher than the INICC rates (CLABSI: 4.9; VAP: 16.5; and CAUTI: 5.3) and CDC-NHSN rates (CLABSI: 0.8; VAP: 1.1; and CAUTI: 1.3). Device use ratios were also higher than the CDC-NHSN and INICC ratios, except for the mechanical ventilator device use ratio, which was lower than the INICC ratio. Resistance of Staphylococcus aureus to oxacillin was 100%. Extra length of stay was 15.1 days for patients with CLABSI, 7.8 days for patients with VAP, and 8.2 days for patients with CAUTI. Extra crude mortality in the ICUs was 18.6% for CLABSI, 17.1% for VAP, and 5.1% for CAUTI. CONCLUSION: Device-associated health care-associated infection rates and most device use ratios in our Mongolian hospitals' ICUs are higher than the CDC-NSHN and INICC rates.

[Using Google Trends to estimate the incidence of influenza-like illness in Argentina]. / Uso de la herramienta Google Trends para estimar la incidencia de enfermedades tipo influenza en Argentina.

The aim of this study was to find a model to estimate the incidence of influenza-like illness (ILI) from the Google Trends (GT) related to influenza. ILI surveillance data from 2012 through 2013 were obtained from the National Health Surveillance System, Argentina. Internet search data were downloaded from the GT search engine database using 6 influenza-related queries: flu, fever, cough, sore throat, paracetamol, and ibuprofen. A Poisson regression model was developed to compare surveillance data and internet search trends for the year 2012. The model's results were validated using surveillance data for the year 2013 and results of the Google Flu Trends (GFT) tool. ILI incidence from the surveillance system showed strong correlations with ILI estimates from the GT model (r = 0.927) and from the GFT tool (r = 0.943). However, the GFT tool overestimates (by nearly twofold) the highest ILI incidence, while the GT model underestimates the highest incidence by a factor of 0.7. These results demonstrate the utility of GT to complement influenza surveillance.

Clinical impact and cost-effectiveness of split-septum and single-use prefilled flushing device vs 3-way stopcock on central line-associated bloodstream infection rates in India: a randomized clinical trial conducted by the International Nosocomial Infection Control Consortium (INICC).

BACKGROUND: Three-way stopcocks (3WSCs) are open systems used on intravenous tubing. Split septums (SSs) are closed systems with prepierced septums. Single-use prefilled flushing devices (SUFs) carry a lower risk of contamination than standard intravenous flushing. 3WSC and standard flushing are widely used in developing countries. This is the first randomized clinical trial (RCT) to compare rates of central line-associated bloodstream infection (CLABSI) between patients using an SS + SUF and those using a 3WSC. METHODS: An RCT with 1096 patients in 5 adult intensive care units was conducted between April 2012 and August 2014 to evaluate their impact on CLABSI rates. Centers for Disease Control and Prevention/National Healthcare Safety Network definitions were applied and International Nosocomial Infection Control Consortium methodology were followed. RESULTS: The study cohort included 547 patients and 3619 central line (CL)-days for the SS + SUF group, and 549 patients and 4061 CL-days for the 3WSC group. CLABSI rates were 2.21 per 1000 CL-days for SS + SUF and 6.40 per 1000 CL-days for 3WSC (relative risk, 0.35; 95% confidence interval [CI], 0.16-0.76; P = .006). The SS + SUF group had significantly better cumulative infection-free catheter survival compared with the 3WSC group (hazard ration, 0.33; 95% CI, 0.15-0.73; P = .006). Using an SS + SUF represents savings of $402.88 and an increase in quality-adjusted life years of 0.0008 per patient. For each extra dollar invested in an SS + SUF, $124 was saved. CONCLUSION: The use of SS + SUF is cost-effective and associated with a significantly lower CLABSI rate compared with the use of 3WSC.

Nosocomial infections in medical-surgical intensive care units in Argentina: attributable mortality and length of stay.

BACKGROUND: Nosocomial infections are an important public health problem in many developing countries, particularly in the intensive care unit (ICU). Limited data exists on the incidence and burden of nosocomial infection in the ICU in Argentina. METHODS: We performed baseline prospective nosocomial infection surveillance of all patients for 6 months in 3 medical-surgical ICUs (MS-ICUs) in Argentina (2 months in each ICU). Nosocomial infections were identified using the Centers for Disease Control and Prevention National Nosocomial Infections Surveillance definitions. Overall and site-specific nosocomial infection rates, attributable mortality, and excess length of hospital stay were calculated. RESULTS: The overall nosocomial infection rate was 27% and 90 per 1000 patient-days. The most common site of infection was catheter-related bloodstream infection (32%), followed by ventilator-associated pneumonia (25%), and catheter-associated urinary tract infection (23%). The rate of central catheter-associated bloodstream infection in the MS-ICU was 44.61 per 1000 device-days, with an attributable mortality of 25%, and 12 attributable extra days of hospital stay. The urinary catheter-associated urinary tract infection rate in the MS-ICU was 22.55 per 1000 urinary catheter-days, with an attributable mortality of 5%, and 5 excess extra days of hospital stay. The ventilator-associated pneumonia rate in the MS-ICU was 50.87 per 1000 ventilator-days with an attributable mortality of 35%, and 10 attributable extra days of hospitalization. CONCLUSION: Our study finds high rates of nosocomial infections in ICUs in Argentina, associated with a considerable attributable mortality and excess length of stay. Ongoing targeted surveillance and implementation of infection control strategies is necessary to control this growing problem.

Cost-effectiveness of prevention strategies for American tegumentary leishmaniasis in Argentina.

The aim of this study was to estimate the cost-effectiveness of reducing tegumentary leishmaniasis transmission using insecticide-impregnated clothing and curtains, and implementing training programs for early diagnosis. A societal perspective was adopted, with outcomes assessed in terms of costs per disability adjusted life years (DALY). Simulation was structured as a Markov model and costs were expressed in American dollars (US$). The incremental cost-effectiveness ratio of each strategy was calculated. One-way and multivariate sensitivity analyses were performed. The incremental cost-effectiveness ratio for early diagnosis strategy was estimated at US$ 156.46 per DALY averted, while that of prevention of transmission with insecticide-impregnated curtains and clothing was US$ 13,155.52 per DALY averted. Both strategies were more sensitive to the natural incidence of leishmaniasis, to the effectiveness of mucocutaneous leishmaniasis treatment and to the cost of each strategy. Prevention of vectorial transmission and early diagnosis have proved to be cost-effective measures.

Uso de la herramienta Google Trends para estimar la incidencia de enfermedades tipo influenza en Argentina / Using Google Trends to estimate the incidence of influenza-like illness in Argentina / Uso da ferramenta Google Trends para estimar a incidência de síndrome gripal na Argentina

El objetivo del presente estudio fue hallar un modelo para estimar la incidencia de enfermedades tipo influenza (ETI), a partir de los términos de búsqueda relacionados recolectados por el Google Trends (GT). Los datos de vigilancia de ETI para los años 2012 y 2013 se obtuvieron del Sistema Nacional de Vigilancia de la Salud de Argentina. Las búsquedas de Internet se obtuvieron de la base de datos del GT, usando 6 términos: gripe, fiebre, tos, dolor de garganta, paracetamol e ibuprofeno. Se desarrolló un modelo de regresión de Poisson a partir de datos del año 2012, y se validó con datos del 2013 y resultados de la herramienta Google Flu Trends (GFT). La incidencia de ETI del sistema de vigilancia presentó fuertes correlaciones con las estimaciones de ETI del GT (r = 0,927) y del GFT (r = 0,943). Sin embargo, el GFT sobreestimó el pico de incidencia por casi el doble, mientras que el modelo basado en el GT subestimó el pico de incidencia por un factor de 0,7. Estos resultados demuestran la utilidad del GT como un complemento para la vigilancia de la influenza.

The aim of this study was to find a model to estimate the incidence of influenza-like illness (ILI) from the Google Trends (GT) related to influenza. ILI surveillance data from 2012 through 2013 were obtained from the National Health Surveillance System, Argentina. Internet search data were downloaded from the GT search engine database using 6 influenza-related queries: flu, fever, cough, sore throat, paracetamol, and ibuprofen. A Poisson regression model was developed to compare surveillance data and internet search trends for the year 2012. The model's results were validated using surveillance data for the year 2013 and results of the Google Flu Trends (GFT) tool. ILI incidence from the surveillance system showed strong correlations with ILI estimates from the GT model (r = 0.927) and from the GFT tool (r = 0.943). However, the GFT tool overestimates (by nearly twofold) the highest ILI incidence, while the GT model underestimates the highest incidence by a factor of 0.7. These results demonstrate the utility of GT to complement influenza surveillance.

O objetivo deste estudo foi encontrar um modelo para estimar a incidência da síndrome gripal com base nos termos de busca relacionados recolhidos pelo Google Trends (GT). Os dados de monitoramento de síndrome gripal entre 2012 e 2013 foram obtidos no Sistema Nacional de Vigilância de Saúde da Argentina. As pesquisas na Internet foram feitas baseando-se no banco de dados do GT usando 6 termos: gripe, febre, tosse, dor de garganta, paracetamol e ibuprofeno. Um modelo de regressão de Poisson foi desenvolvido valendo-se de dados de 2012. O modelo foi ajustado e validado com dados de 2013 e comparado com os resultados da ferramenta Google Flu Trends (GFT). A incidência de síndrome gripal mostrou uma forte correlação com estimativas do GT (r = 0,927) e GFT (r = 0,943). No entanto, o GFT superestimou o pico de incidência por quase o dobro, e o modelo baseado no GT subestimou o pico de incidência por um fator de 0,7. Esses resultados demonstram a utilidade do GT como um suplemento para a vigilância da influenza.

[Cost-benefit analysis of vector control in areas of potential dengue transmission]. / Análisis costo-beneficio del control de vectores en la transmisión potencial de dengue.

OBJECTIVES: To evaluate the cost-benefit of an intervention utilizing fumigation against adult mosquitoes along with actions to control immature Aedes aegypti to prevent transmission in a high-risk area. METHODS: A cost-benefit analysis was performed from the social perspective. A program to control both adult mosquitoes and immature forms was compared to a nonintervention hypothesis, from January to April 2007, in the city of Clorinda, Argentina. Direct costs, as well as indirect and intangible benefits, were taken into account and standardized in international dollars (I$) using purchasing power parity. An incidence rate of 50 cases of dengue per 1000 inhabitants was used in the non-intervention hypothesis. RESULTS: From January to April 2007 there were 176 cases of dengue in Clorinda, but only five were autochthonous. The net present value was I$ 196,879 with the control strategy, whereas the non-intervention was calculated to be I$ -106,724, indicating a savings of I$ 303,602 (I$ 6.46 per inhabitant) for the intervention. The sensitivity analysis showed that, with more than 1363 cases of dengue (total incidence rate of 29 per 1000 inhabitants) and one case of dengue hemorrhagic fever, there is a cost-benefit to intervention. CONCLUSIONS: The results suggest that vector control, including fumigation of adult mosquitoes, should be considered in high-risk areas as a cost-effective option for nonendemic countries.

Cost-effectiveness of prevention strategies for American tegumentary leishmaniasis in Argentina / Custo-efetividade de estratégias de prevenção contra a leishmaniose tegumentar americana na Argentina / Coste-efectividad de estrategias de prevención contra la leishmaniasis tegumentaria americana en Argentina

The aim of this study was to estimate the cost-effectiveness of reducing tegumentary leishmaniasis transmission using insecticide-impregnated clothing and curtains, and implementing training programs for early diagnosis. A societal perspective was adopted, with outcomes assessed in terms of costs per disability adjusted life years (DALY). Simulation was structured as a Markov model and costs were expressed in American dollars (US$). The incremental cost-effectiveness ratio of each strategy was calculated. One-way and multivariate sensitivity analyses were performed. The incremental cost-effectiveness ratio for early diagnosis strategy was estimated at US$ 156.46 per DALY averted, while that of prevention of transmission with insecticide-impregnated curtains and clothing was US$ 13,155.52 per DALY averted. Both strategies were more sensitive to the natural incidence of leishmaniasis, to the effectiveness of mucocutaneous leishmaniasis treatment and to the cost of each strategy. Prevention of vectorial transmission and early diagnosis have proved to be cost-effective measures.

O objetivo deste estudo foi estimar o custo-efetividade para reduzir a transmissão da leishmaniose tegumentar americana, utilizando roupas e cortinas impregnadas com inseticidas e implementando programas de treinamento para o diagnóstico precoce. Adotou-se uma perspectiva social, usando os anos de vida ajustados por incapacidade (AVAI). Estruturou-se uma simulação com o modelo de Markov. Os custos foram expressos em US$. A taxa de custo-efetividade incremental foi calculada para cada estratégia. Foi desenvolvida análise de sensibilidade, uni e multivariada. A taxa de custo- efetividade incremental para o diagnóstico precoce foi estimada em US$ 156,46 por AVAI evitado, enquanto a taxa para prevenção com roupas e cortinas impregnadas foi de US$ 13.155,53 por AVAI evitado. Ambas as estratégias foram mais sensíveis à incidência natural de leishmaniose, à efetividade do tratamento contra a leishmaniose mucocutânea e ao custo de cada estratégia. A prevenção da transmissão vetorial e o diagnóstico precoce provaram ser medidas custo-efetivos.

El objetivo de este estudio fue estimar el coste-efectividad de reducir la transmisión de la leishmaniasis tegumentaria americana utilizando ropas y cortinas impregnadas con insecticidas, e implementando programas de entrenamiento para el diagnostico temprano. Se adoptó una perspectiva social, utilizando los años de vida ajustados por discapacidad (AVAD). Se estructuró una simulación con un modelo de Markov. Los costes fueron expresados en dólares americanos (US$). La razón de coste-efectividad incremental fue calculada para cada estrategia. Se desarrollaron análisis de sensibilidad de una vía y multivariados. La razón de coste-efectividad incremental para el diagnóstico temprano fue estimada en US$ 156,46 por AVAD evitado, mientras que la razón de coste-efectividad incremental para la prevención con ropa y cortinas impregnadas fue de US$ 13.155,52 por AVAD evitado. Ambas estrategias fueron más sensibles a la incidencia natural de leishmaniasis, a la efectividad del tratamiento contra leishmaniasis mucosa y al coste de cada estrategia. La prevención de la transmisión vectorial y el diagnóstico temprano han probado ser medidas coste-efectivas.

Nuevo método para elaborar corredores endémicos / New method for determining endemic levels

OBJETIVO: Diseñar un instrumento para elaborar corredores o canales endémicos mediante cálculos sencillos y, en el caso de enfermedades transmisibles, identificar y estimar parámetros relacionados con la dinámica de la transmisión. MÉTODOS: Se obtuvieron parámetros para elaborar una curva teórica de incidencia esperada, basada en el modelo logístico de crecimiento. Los parámetros se estimaron por medio de una regresión no lineal, a partir de datos de incidencia acumulada de los cinco años anteriores. Se tomó como ejemplo la incidencia semanal acumulada de casos de enfermedad tipo influenza para Argentina en 2009 y se la comparó con la serie de casos de 2004 a 2008 para construir los canales endémicos acumulados y no acumulados. RESULTADOS: De acuerdo a los canales endémicos acumulados obtenidos, el país entró en zona de brote a partir de la semana dos. El máximo número esperado de casos o capacidad de carga (K) de acuerdo a los datos de años previos fue de 1 090 660. Considerando los corredores no acumulados, la situación de brote se presentó en 34 de las 51 semanas. Se estimó un rango para la tasa básica de reproducción (R0) de 1,05 a 1,13 para el período no epidémico 2004-2008. CONCLUSIONES: El nuevo método permitió elaborar canales endémicos de una manera sencilla, con la obtención de parámetros importantes para la transmisión. Si bien tiene limitaciones, entre ellas que la ecuación utilizada es más útil para evaluar enfermedades con un ciclo anual marcado y menos exacta para ciclos menores de un año, puede ser considerado como una alternativa valiosa para elaborar corredores endémicos y una nueva contribución al estudio de brotes epidémicos en los niveles locales de vigilancia de la salud.

OBJECTIVE: Design an instrument for determining endemic levels or ranges using simple calculations; identify and estimate the parameters related to the dynamic transmission of communicable diseases. METHODS: The parameters for establishing a theoretical curve of expected incidence based on the logistic growth model were identified. The parameters were estimated by nonlinear regression based on the cumulative incidence data from the previous five years. The weekly cumulative incidence of cases of influenza-like illness in Argentina in 2009 was used as an example. It was compared to the 2004-2008 case series in order to determine the cumulative and non-cumulative endemic levels. RESULTS: According to the cumulative endemic levels identified, the country entered the outbreak area in week 2. The data from previous years showed that the maximum expected number of cases or carrying capacity (K) was 1 090 660. When the non-cumulative levels were considered, the outbreak was present in 34 out of 51 weeks. A range of 1.05 to 1.13 was estimated for the basic reproductive rate (R0) in the non-epidemic period from 2004-2008. CONCLUSIONS: The new method facilitated the determination of endemic levels using a simple procedure with the identification of parameters that are important for transmission. Although it has limitations such as the fact that the equation used is more appropriate for evaluating diseases with a pronounced annual cycle and less accurate for cycles of less than 1 year, it can be considered a valuable alternative method for determining endemic ranges and a new contribution to the study of epidemic outbreaks at local health surveillance levels.

Phlebotominae spatial distribution asssociated with a focus of tegumentary leishmaniasis in Las Lomitas, Formosa, Argentina, 2002.

Las Lomitas, Formosa, Argentina, reported 96 cases of tegumentary leishmaniasis during 2002. The urban transmission was suggested although previous outbreaks were related with floods of the Bermejo river (BR) 50 km from the village. Phlebotomine collections were performed during March 2002 to define the spatial distribution of risk, together with satellite imaginery. The phlebotomine/trap obtained was 1679.5 in the southern BR shore, 1.1 in the periruban-rural environment and 2.3 in the northern Pilcomayo river marshes. Lutzomyia neivai was the prevalent species (91.1%) among the 2393 phlebotomine captured, and it was only found in the BR traps. The other species were L. migonei (7.9%), L. cortelezzii (0.9%), and Brumptomyia guimaraesi (0.1%). The satellite images analysis indicates that the fishing spots at the BR were significantly overflowed during the transmission peak, consistent with fishermen recollections. This spatial restricted flood might concentrate vectors, reservoirs, and humans in high places. Therefore, both the spatial distribution of vectors and the sensor remoting data suggests that in Las Lomitas area the higher transmission risk it is still related with the gallery forest of the BR, despite of the urban residence of the cases. The surveillance and control implications of these results are discussed.

Tegumentary leishmaniasis outbreak in Bella Vista City, Corrientes, Argentina during 2003.

Bella Vista City, Corrientes, Argentina, reported an epidemic outbreak of tegumentary leishmaniasis during 2003. The mean age of the 31 cases was 25.0 +/- 13.7 years old, with a sex ratio male:female 1.8, and without mucosal involvement. They clustered in two contiguous neighbourhoods, 96% in the periurban border and 4% in the peripheral outskirts. The transmission peak was estimated to have occurred during April 2003. Four species (3608 sand flies) were captured in nine sites: Lutzomyia neivai (90.1%), Lu. pessoai (8.9%), Lu. migonei (0.8 %), and Brumptomyia avellari (0.2 %). The outskirts/rural capture ratio of Lu. neivai was up to 3, and the outskirts/periurban up to 200. Therefore, the 'urban' transmission in this southernmost known focus is still an ecotone-border associated risk. The changes in human distribution or activities, patches of the secondary vegetation, periurban streams, rainfall of the previous year, and river period floods could all contribute to 'urban' outbreaks in the region. Tegumentary leishmaniasis risk should be assessed for any project that involves changes in land use throughout an endemic area.