Search

OBJETIVO: Identificar si existe una asociación negativa entre los niveles de plomo en sangre y la coordinación visomotora y el equilibrio de escolares. MATERIAL Y MÉTODOS: Se realizó un estudio transversal en 255 niños de 8 a 10 años de edad, que asistían a escuelas del Sector 1 del Instituto de Educación Pública del Estado de Oaxaca, durante noviembre y diciembre de 1998. Se les aplicaron las pruebas de evaluación de la percepción visual de Frostig y la subescala de equilibrio Frostig Movement Skills Test Battery y se les tomó una muestra de sangre para la determinación de plomo por medio de espectrometría de absorción atómica. Asimismo, se aplicó un cuestionario sociodemográfico y se evaluó la historia de salud del niño. Se relacionó el nivel de plomo sanguíneo con los resultados de las pruebas de percepción visual y del equilibrio mediante modelos de regresión múltiple. Se usó la técnica de simulaciones de Montecarlo para probar el efecto del plomo dentro del modelo. RESULTADOS: La media geométrica de las concentraciones de plomo en sangre fue de 11.5 µg/dl (DE geométrica= +6.3, -5.2). El nivel de plomo se relacionó significativamente con el cociente de integración visomotora (p>0.042). Este disminuye 1.78 (IC 95% -3.51, -0.06) puntos por cada incremento de 10 µg/dl en los niveles de plomo en sangre del niño. De las pruebas que constituyeron este cociente, sólo se relacionó significativamente el plomo con la de coordinación ojo-mano (p=0.045) y de relaciones espaciales (p=0.039). El ingreso familiar también se relacionó significativamente con el cociente de integración visomotora, a mayor ingreso los resultados en las pruebas del niño fueron más altos. Sólo 3.1% de los niños obtuvieron puntuaciones consideradas clínicamente anormales. No se encontró una relación significativa entre el plomo y el cociente de la respuesta motriz reducida, el cociente de percepción visual general y las pruebas de equilibrio. CONCLUSIONES: La relación negativa entre el plomo y la habilidad visomotora concuerda con los resultados encontrados en niños en otros países. Al parecer las concentraciones de plomo en sangre, que son comunes en los niños de Oaxaca, son suficientes para ocasionar una limitación visomotora de naturaleza sutil. Los resultados de este estudio señalan la necesidad de reforzar la iniciativa de reducir la exposición de los niños a las fuentes de exposición conocidas, en especial barro vidriado y, por lo tanto, reducir los niveles poblacionales de plomo en sangre.

INTRODUCTION The percentage of asymptomatic COVID-19 cases worldwide is estimated at 18-50%; 53% in Cuba specifically, and 58% in Havana, the Cuban capital and the 2020 epicenter of the country's COVID-19 epidemic. These figures, however, do not represent the transmission capacity or behavior of asymptomatic cases. Understanding asymptomatic transmission's contribution to SARS-CoV-2 spread is of great importance to disease control and prevention. OBJECTIVE Identify the epidemiological implications of asymptomatic SARS-CoV-2 infection in Havana, Cuba, during the first wave of the epidemic in 2020. METHODS We carried out a cross-sectional study of all confirmed COVID-19 cases diagnosed in Havana, Cuba, from March 16 through June 30, 2020. The information was obtained through review of the standardized form for investigation of suspected and confirmed cases. Examined variables included age, sex, occupation, case type and source of infection. Cases were divided into asymptomatic and symptomatic groups, and transmission was characterized through the creation of a contact matrix. Analysis was carried out in Epidat and R. RESULTS We studied 1287 confirmed cases, of which 57.7% (743) were asymptomatic, and 42.3% (544) were symptomatic. Symptomatic presentation was the most common for both imported and introduced cases, while asymptomatic presentation was more common in autochthonic cases and infectionsfroman undetermined source. Asymptomaticinfection was more common in groups aged <20 and 20-59 years, while symptomatic infection was more common in those aged >60 years. In the contact matrix, 34.6% of cases (445/1287) were not tied to other cases, and 65.4% (842/1287) were infectious-infected dyads, with symptomatic-symptomatic being the most common combination. The majority of primary cases (78.5%; 1002/1276) did not generate secondary cases, and 85.6% (658/743) of asymptomatic cases did not lead to other cases (although one asymptomatic superspreader led to 90 cases in a single event). However, 63.2% (344/544) of symptomatic primary cases generated secondary cases, and 11 symptomatic superspreaders spawned 100 secondary cases in different events. CONCLUSIONS Asymptomatic SARS-CoV-2 infection was the most common form of COVID-19 in Havana during the study period, but its capacity for contagion was lower than that of symptomatic individuals. Superspreader events under specific conditions played an important role in sustaining [ABSTRACT FROM AUTHOR]

Objective: To identify the relationship between emergency visits for acute respiratory illnesses, acute bronchial asthma crisis (ABAC) and acute respiratory infections (ARI), in children less than 14 years of age, and the daily changes of air pollutant levels, in two central hospitals of Havana City, between October 1st 1996 and March 16 1998., Material and Methods: An ecological time series study was conducted. We assessed the relationship between the presence of acute respiratory illnesses, ABAC, and IRA, and exposure to levels of particles less than 10 microg/m3 (PM10), smoke, and sulfur dioxide (SO2); negative binomial regression models were used to assess latency periods of one to five days as well as the cumulative effect of seven days before the emergency visit., Results: The levels of atmospheric pollutants were low, in general. The 24-hour mean values for PM10 levels, smoke, and SO2, were 59.2 microg/m3 (SD=29.2), 27.7 microg/m3 (SD=21.2), and 21.1 microg/m3 (SD=20.1), respectively. An increase of 20 microg/m3 in the daily average of black smoke was associated with a 2.2% increase (95% CI 0.9-3.6) in the number of emergency visits for ABAC. A 20 microg/m3 increase in the daily average of black smoke and SO was associated with an increase in ARI of 2.4% (95% CI 1.2-3.6), and 5% (95% CI 1.3-5.3), respectively, with a 5-day lag. We also observed a cumulative effect for all the contaminants studied., Conclusions: These results suggest that air pollution levels in Havana City affect children's respiratory health; therefore implementation of control measures is necessary, especially those aimed at decreasing motor vehicle exhaust fumes. The English version of this paper is available at: http://www.insp.mx/salud/index.html.