Natural ventilation for the prevention of airborne contagion.

BACKGROUND: Institutional transmission of airborne infections such as tuberculosis (TB) is an important public health problem, especially in resource-limited settings where protective measures such as negative-pressure isolation rooms are difficult to implement. Natural ventilation may offer a low-cost alternative. Our objective was to investigate the rates, determinants, and effects of natural ventilation in health care settings. METHODS AND FINDINGS: The study was carried out in eight hospitals in Lima, Peru; five were hospitals of "old-fashioned" design built pre-1950, and three of "modern" design, built 1970-1990. In these hospitals 70 naturally ventilated clinical rooms where infectious patients are likely to be encountered were studied. These included respiratory isolation rooms, TB wards, respiratory wards, general medical wards, outpatient consulting rooms, waiting rooms, and emergency departments. These rooms were compared with 12 mechanically ventilated negative-pressure respiratory isolation rooms built post-2000. Ventilation was measured using a carbon dioxide tracer gas technique in 368 experiments. Architectural and environmental variables were measured. For each experiment, infection risk was estimated for TB exposure using the Wells-Riley model of airborne infection. We found that opening windows and doors provided median ventilation of 28 air changes/hour (ACH), more than double that of mechanically ventilated negative-pressure rooms ventilated at the 12 ACH recommended for high-risk areas, and 18 times that with windows and doors closed (p < 0.001). Facilities built more than 50 years ago, characterised by large windows and high ceilings, had greater ventilation than modern naturally ventilated rooms (40 versus 17 ACH; p < 0.001). Even within the lowest quartile of wind speeds, natural ventilation exceeded mechanical (p < 0.001). The Wells-Riley airborne infection model predicted that in mechanically ventilated rooms 39% of susceptible individuals would become infected following 24 h of exposure to untreated TB patients of infectiousness characterised in a well-documented outbreak. This infection rate compared with 33% in modern and 11% in pre-1950 naturally ventilated facilities with windows and doors open. CONCLUSIONS: Opening windows and doors maximises natural ventilation so that the risk of airborne contagion is much lower than with costly, maintenance-requiring mechanical ventilation systems. Old-fashioned clinical areas with high ceilings and large windows provide greatest protection. Natural ventilation costs little and is maintenance free, and is particularly suited to limited-resource settings and tropical climates, where the burden of TB and institutional TB transmission is highest. In settings where respiratory isolation is difficult and climate permits, windows and doors should be opened to reduce the risk of airborne contagion

Tuberculosis and Cardiovascular Disease: Linking the Epidemics

The burden of tuberculosis and cardiovascular disease (CVD) is enormous worldwide. CVD rates are rapidly increasing in low- and middle-income countries. Public health programs have been challenged with the overlapping tuberculosis and CVD epidemics. Monocyte/macrophages, lymphocytes and cytokines involved in cellular mediated immune responses against Mycobacterium tuberculosis are also main drivers of atherogenesis, suggesting a potential pathogenic role of tuberculosis in CVD via mechanisms that have been described for other pathogens that establish chronic infection and latency. Studies have shown a pro-atherogenic effect of antibody-mediated responses against mycobacterial heat shock protein-65 through cross reaction with self-antigens in human vessels. Furthermore, subsets of mycobacteria actively replicate during latent tuberculosis infection (LTBI), and recent studies suggest that LTBI is associated with persistent chronic inflammation that may lead to CVD. Recent epidemiologic work has shown that the risk of CVD in persons who develop tuberculosis is higher than in persons without a history of tuberculosis, even several years after recovery from tuberculosis. Together, these data suggest that tuberculosis may play a role in the pathogenesis of CVD. Further research to investigate a potential link between tuberculosis and CVD is warranted

COVID-19 pandemic, medical attention, and self-care of patients with type 2 diabetes at a Peru-based hospital: An analytical cross-sectional study

"Background: To determine the association between coronavirus disease-2019 (COVID-19), medical attention and self-care of patients with type 2 diabetes (T2DM) at the Archbishop Loayza National Hospital. Methods: This analytical cross-sectional study, involved interviewing 181 T2DM patients and recording their actions regarding three aspects–self-care measures, medical care, and spending on medicines–before and during the pandemic. The relationships between the variables were established using descriptive and analytical statistics. Results: During the pandemic, self-care decreased to 37%; 26% had access to medical care. Patients in the provinces experienced better self-care (Lima: 35%; Provinces: 61%; p=0.002). Patients with comorbidities also took good care of themselves (with comorbidities: 41%; without comorbidities: 29%; p=0.036). Conclusions: COVID-19 had a negative influence on T2DM patients regarding self-care and medical care. One out of four patients received medical care. Additionally, being outside Lima and having comorbidities were associated with better self-care during the pandemic.

MORTALIDAD PERINATAL HOSPITALARIA EN EL PERÚ: FACTORES DE RIESGO

Objetivo: Identificar los factores de riesgo de la mortalidad perinatal hospitalaria en el Perú y determinar su valor predictivo. Material y Método: Estudio de casos y controles, utilizando información del Sistema Informático Perinatal de 9 hospitales del Ministerio de Salud del año 2000. Se incluyó madres con productos &#382;1000 g. Para el análisis las tasas de expresaron por mil nacidos vivos (nv), Odds Ratio (OR) con intervalo de confianza al 95%, regresión logística y curvas ROC. Resultados: La tasa de mortalidad perinatal hospitalaria en el Perú en 2000 fue 22,9/1000 nv. Los factores de riesgo fueron: región sierra (OR=2,1), altitud >3000 metros sobre el nivel del mar (OR=1,8), baja escolaridad (OR=2,3), edad materna 35 años a más (OR=1,6), antecedente de muerte fetal (OR=1,9), corto período intergenésico (OR=4,5), multiparidad (OR=1,9), ausencia de control prenatal (OR=2,1), presentación anómala (OR=4,3), patología materna (OR=2,4) y neonatal (OR=56,7), bajo peso al nacer (OR=9,8), prematurez (OR=5,6), desnutrición intrauterina (OR=5,5), Apgar bajo al minuto y 5 minutos (OR=4,3 y 46,6). Cinco factores de riesgo tuvieron alto valor predictivo (96%): bajo peso, prematuridad, depresión al nacer, morbilidad neonatal y multiparidad. Conclusión: Los factores de riesgo relacionados al recién nacido tuvieron mayor valor predictivo para mortalidad perinatal que los factores de riesgo materno

Search for massive rare particles with the SLIM experiment

The search for magnetic monopoles in the cosmic radiation remains one of the main aims of non-accelerator particle astrophysics. Experiments at high altitude allow lower mass thresholds with respect to detectors at sea level or underground. The SLIM experiment is a large array of nuclear track detectors at the Chacaltaya High Altitude Laboratory (5290 m a.s.l.). The results from the analysis of 171 m$^2$ exposed for more than 3.5 y are here reported. The completion of the analysis of the whole detector will allow to set the lowest flux upper limit for Magnetic Monopoles in the mass range 10$^5$ - 10$^{12}$ GeV. The experiment is also sensitive to SQM nuggets and Q-balls, which are possible Dark Matter candidates.Comment: Presented at the 29-th ICRC, Pune, India (2005

Impact of infection control measures to control an outbreak of multidrug-resistant tuberculosis in a human immunodeficiency virus ward, Peru

Multidrug-resistant tuberculosis (MDRTB) rates in a human immunodeficiency virus (HIV) care facility increased by the year 2000-56% of TB cases, eight times the national MDRTB rate. We reported the effect of tuberculosis infection control measures that were introduced in 2001 and that consisted of 1) building a respiratory isolation ward with mechanical ventilation, 2) triage segregation of patients, 3) relocation of waiting room to outdoors, 4) rapid sputum smear microscopy, and 5) culture/drug-susceptibility testing with the microscopic-observation drug-susceptibility assay. Records pertaining to patients attending the study site between 1997 and 2004 were reviewed. Six hundred and fifty five HIV/TB-coinfected patients (mean age 33 years, 79% male) who attended the service during the study period were included. After the intervention, MDRTB rates declined to 20% of TB cases by the year 2004 (P = 0.01). Extremely limited access to antiretroviral therapy and specific MDRTB therapy did not change during this period, and concurrently, national MDRTB prevalence increased, implying that the infection control measures caused the fall in MDRTB rates. The infection control measures were estimated to have cost US$91,031 while preventing 97 MDRTB cases, potentially saving US$1,430,026. Thus, this intervention significantly reduced MDRTB within an HIV care facility in this resource-constrained setting and should be cost-effective

Search for Intermediate Mass Magnetic Monopoles and Nuclearites with the SLIM experiment

SLIM is a large area experiment (440 m2) installed at the Chacaltaya cosmic ray laboratory since 2001, and about 100 m2 at Koksil, Himalaya, since 2003. It is devoted to the search for intermediate mass magnetic monopoles (107-1013 GeV/c2) and nuclearites in the cosmic radiation using stacks of CR39 and Makrofol nuclear track detectors. In four years of operation it will reach a sensitivity to a flux of about 10-15 cm-2 s-1 sr-1. We present the results of the calibration of CR39 and Makrofol and the analysis of a first sample of the exposed detector.Comment: Presented at the 22nd ICNTS, Barcelona 200

Language in tuberculosis services: can we change to patient-centred terminology and stop the paradigm of blaming the patients?

The words 'defaulter', 'suspect' and 'control' have been part of the language of tuberculosis (TB) services for many decades, and they continue to be used in international guidelines and in published literature. From a patient perspective, it is our opinion that these terms are at best inappropriate, coercive and disempowering, and at worst they could be perceived as judgmental and criminalising, tending to place the blame of the disease or responsibility for adverse treatment outcomes on one side-that of the patients. In this article, which brings together a wide range of authors and institutions from Africa, Asia, Latin America, Europe and the Pacific, we discuss the use of the words 'defaulter', 'suspect' and 'control' and argue why it is detrimental to continue using them in the context of TB. We propose that 'defaulter' be replaced with 'person lost to follow-up'; that 'TB suspect' be replaced by 'person with presumptive TB' or 'person to be evaluated for TB'; and that the term 'control' be replaced with 'prevention and care' or simply deleted. These terms are non-judgmental and patient-centred. We appeal to the global Stop TB Partnership to lead discussions on this issue and to make concrete steps towards changing the current paradigm

High energy hadrons in EAS at mountain altitude

An extensive simulation has been carried out to estimate the physical interpretation of dynamical factors such as , in terms of high energy interaction features, concentrated in the present analysis on the average transverse momentum. It appears that the large enhancement observed for versus primary energy, suggesting in earliest analysis a significant rise of with energy, is only the result of the limited resolution of the detectors and remains in agreement with a wide range of models used in simulations.Comment: 13 pages, 6 PostScript figures, LaTeX Subm. to JPhys

The detection of airborne transmission of tuberculosis from HIV-infected patients, using an in vivo air sampling model

Background. Nosocomial transmission of tuberculosis remains an important public health problem. We created an in vivo air sampling model to study airborne transmission of tuberculosis from patients coinfected with human immunodeficiency virus (HIV) and to evaluate environmental control measures. Methods. An animal facility was built above a mechanically ventilated HIV‐tuberculosis ward in Lima, Peru. A mean of 92 guinea pigs were continuously exposed to all ward exhaust air for 16 months. Animals had tuberculin skin tests performed at monthly intervals, and those with positive reactions were removed for autopsy and culture for tuberculosis. Results. Over 505 consecutive days, there were 118 ward admissions by 97 patients with pulmonary tuberculosis, with a median duration of hospitalization of 11 days. All patients were infected with HIV and constituted a heterogeneous group with both new and existing diagnoses of tuberculosis. There was a wide variation in monthly rates of guinea pigs developing positive tuberculin test results (0%–53%). Of 292 animals exposed to ward air, 159 developed positive tuberculin skin test results, of which 129 had laboratory confirmation of tuberculosis. The HIV‐positive patients with pulmonary tuberculosis produced a mean of 8.2 infectious quanta per hour, compared with 1.25 for HIV‐negative patients with tuberculosis in similar studies from the 1950s. The mean monthly patient infectiousness varied greatly, from production of 0–44 infectious quanta per hour, as did the theoretical risk for a health care worker to acquire tuberculosis by breathing ward air. Conclusions. HIV‐positive patients with tuberculosis varied greatly in their infectiousness, and some were highly infectious. Use of environmental control strategies for nosocomial tuberculosis is therefore a priority, especially in areas with a high prevalence of both tuberculosis and HIV infection