A highly transmissible tuberculosis outbreak: the importance of bars.

The transmission of tuberculosis (TB) in bars is difficult to study. The objective was to describe a large TB outbreak in a company's bar and other leisure settings. A descriptive study of a TB outbreak was carried out. Contacts were studied in the index case's workplace bar (five circles of contacts) and other recreational areas (social network of three bars in the index case's neighbourhood). Chest X-rays were recommended to contacts with positive tuberculin skin tests (TST) (⩾5 mm). The risk of latent tuberculosis infection (LTBI) was determined using an adjusted odds ratio. The dose-response relationship was determined using the chi-square test for linear trend. We studied 316 contacts at the index case's workplace and detected five new cases of TB. The prevalence of LTBI was 57·9% (183/316) and was higher in the first circle, 96·0% (24/25), and lower in the fifth, 46·5% (20/43) (P < 0·0001). Among 58 contacts in the three neighbourhood bars, two TB cases were detected and the LTBI prevalence was 51·7% (30/58). Two children of one secondary TB company patient became ill. Bars may be transmission locations for TB and, as they are popular venues for social events, should be considered as potential areas of exposure.

Brote masivo de intoxicación por monóxido de carbono en los telespectadores de un partido de fútbol / Mass carbon monoxide poisoning among television viewers of a football match

Introducción. El objetivo fue estudiar un brote de intoxicación por monóxido de carbono (CO) y las características de los casos asintomáticos. Métodos. El 2 de febrero de 2015 un grupo de más de 30 telespectadores de un partido de fútbol contactó con el servicio de urgencias por una supuesta intoxicación por CO procedente de una estufa de butano. Se realizó una inspección ocular del local de la exposición y un estudio epidemiológico descriptivo. Según el tipo de variables, la existencia de una asociación estadística se estudió con la prueba exacta de Fisher o el test de Kruskal-Wallis. Resultados. Se vieron afectados 34 de 39 sujetos (87,2%). Los expuestos tenían una media de edad de 43,8años (DE=22,1) y el 28,2% (11/39) eran mujeres. El tiempo de exposición fue de 52,4min (DE=21,0) y la distancia a la estufa de 4,2m (DE=2,5). Los síntomas más frecuentes fueron cefalea (50%), náuseas (20,6%), pérdida de fuerza (20,6%) y vértigo (14,7%). Los niveles de carboxihemoglobina (COHb) fueron muy elevados (13,8%±5,8). El 97,1% precisó oxigenoterapia y el 39,4% tratamiento en cámara hiperbárica. Un 29,5% de los casos no presentaron síntomas, y respecto a los casos sintomáticos, estos mostraron niveles similares de COHb (13,6% vs. 15,3%, diferencia no significativa), pero un tiempo de exposición inferior (38,3min vs. 53,3min; p<0,036). Conclusiones. Casi una tercera parte de las personas expuestas fueron asintomáticas aun con niveles de COHb similares a los casos sintomáticos, e incluso la mayoría precisaron tratamiento con oxígeno en cámara hiperbárica (AU)

Background. The objective was to study a mass carbon monoxide (CO) poisoning and the characteristics of the asymptomatic cases. Methods. On the 2nd of February, 2015, a group of more than 30 television viewers of a football match contacted the emergency department due to suspected CO poisoning from a butane stove. A visual inspection of the location of the exposure and a descriptive epidemiological study were conducted. Based on the type of variable, the presence of a statistical association was studied with Fisher's exact test or the Kruskal-Wallis test. Results. Thirty-four of the 39 individuals were affected (87.2%). The exposed individuals had a mean age of 43.8 years (SD, 22.1), and 28.2% (11/39) were women. The time of exposure was 52.4min (SD, 21.0), and the mean distance from the oven was 4.2m (SD, 2.5). The most common symptoms were headache (50%), nausea (20.6%), weakness (20.6%) and dizziness (14.7%). The carboxyhaemoglobin (COHb) levels were very high (13.8% ±5.8%). Some 97.1% of the individuals required oxygen therapy, and 39.4% required hyperbaric chamber treatment. Some 29.5% of the cases had no symptoms but showed COHb levels similar to those that did have symptoms (13.6% vs. 15.3%, nonsignificant difference). The asymptomatic cases had a shorter exposure time (38.3min vs. 53.3min; P<.036). Conclusions. Almost a third of the exposed individuals were asymptomatic, even with COHb levels similar to those of the symptomatic patients, and the majority of these asymptomatic patients even required oxygen treatment in a hyperbaric chamber (AU)

Mass carbon monoxide poisoning among television viewers of a football match. / Brote masivo de intoxicación por monóxido de carbono en los telespectadores de un partido de fútbol.

BACKGROUND: The objective was to study a mass carbon monoxide (CO) poisoning and the characteristics of the asymptomatic cases. METHODS: On the 2nd of February, 2015, a group of more than 30 television viewers of a football match contacted the emergency department due to suspected CO poisoning from a butane stove. A visual inspection of the location of the exposure and a descriptive epidemiological study were conducted. Based on the type of variable, the presence of a statistical association was studied with Fisher's exact test or the Kruskal-Wallis test. RESULTS: Thirty-four of the 39 individuals were affected (87.2%). The exposed individuals had a mean age of 43.8 years (SD, 22.1), and 28.2% (11/39) were women. The time of exposure was 52.4min (SD, 21.0), and the mean distance from the oven was 4.2m (SD, 2.5). The most common symptoms were headache (50%), nausea (20.6%), weakness (20.6%) and dizziness (14.7%). The carboxyhaemoglobin (COHb) levels were very high (13.8% ±5.8%). Some 97.1% of the individuals required oxygen therapy, and 39.4% required hyperbaric chamber treatment. Some 29.5% of the cases had no symptoms but showed COHb levels similar to those that did have symptoms (13.6% vs. 15.3%, nonsignificant difference). The asymptomatic cases had a shorter exposure time (38.3min vs. 53.3min; P<.036). CONCLUSIONS: Almost a third of the exposed individuals were asymptomatic, even with COHb levels similar to those of the symptomatic patients, and the majority of these asymptomatic patients even required oxygen treatment in a hyperbaric chamber.

Norovirus gastroenteritis outbreak transmitted by food and vomit in a high school.

We investigated an outbreak of norovirus that affected students and teachers of a high school in Lleida, Spain through various transmission mechanisms. A case-control epidemiological study of the risk of disease and the relative importance of each mode of transmission was carried out. Cases and controls were selected from a systematic sample of students and teachers present at the school on 28 January. Faecal samples were taken from three food handlers and 16 cases. The influence of each factor was studied using the adjusted odds ratio (aOR) and the estimated population attributable risk (ePAR) with 95% confidence intervals (CI). We interviewed 210 people (42 cases, 168 controls). The proportion of symptoms in these individuals was nausea 78·6%, vomiting 59·5%, diarrhoea 45·2%, and fever 19·0%. The epidemic curve showed transmission for at least 4 days. The risk of disease was associated with exposure to food (aOR 5·8) in 66·1% of cases and vomit (aOR 4·7) in 24·8% of cases. Faecal samples from 11 patients and two food handlers were positive for norovirus GII.12 g. Vomit may co-exist with other modes of transmission in norovirus outbreaks and could explain a large number of cases.

Smoking in tuberculosis patients increases the risk of infection in their contacts.

OBJECTIVE: To determine the risk of latent tuberculous infection (LTBI) among contacts of smokers with tuberculosis (TB). METHODS: A study was conducted to determine the prevalence of LTBI among contacts of TB cases aged >14 years in Catalonia, Spain. A survey was carried out for each TB case and their contacts. LTBI was diagnosed using the tuberculin skin test (≥5 mm). The risk of LTBI associated with smoking was determined by multi-variate logistic regression analysis, with adjusted odds ratio (aOR) and their 95% confidence intervals (CI). RESULTS: The smoking prevalence among TB cases was 40.7% (439/1079). The prevalence of LTBI among their contacts was 29.7% (2281/7673). It was higher among contacts of smoking index cases (35.3%) than among those of non-smokers (25.7%). Smoking was independently associated with an increased risk of LTBI among contacts (aOR 1.5, 95%CI 1.3-1.7), and was estimated to be responsible for 12.8% of infections. CONCLUSIONS: Index case smoking increases the risk of LTBI and should be systematically investigated. A reduction in smoking could lower the risk of infection substantially.

[Waterborne outbreak of gastroenteritis caused by Norovirus transmitted through drinking water]. / Brote de gastroenteritis por Norovirus causado por el consumo de agua de suministro público.

BACKGROUND: The aim of this study was to conduct an investigation into an outbreak of waterborne disease caused by Norovirus due to the consumption of contaminated drinking water. METHODS: The first week after the school summer holidays we detected an outbreak of gastroenteritis at a school in Borges Blanques (Lleida, Spain). A retrospective cohort study was carried out to investigate: water consumption and food (six items). We assessed RNA Norovirus by RT-PCR in 6 stool samples. The risk of gastroenteritis was assessed by applying adjusted risk ratio (RRa) analysis at 95% confidence intervals (CI). RESULTS: The overall attack rate was 45% (96/213). The main symptoms were: abdominal pain, 88.4% (84/95); nausea, 65.9% (62/94), and vomiting, 64.6% (62/96). The consumption of school drinking water was statistically associated with the disease (RRa: 2.8; 95% CI: 1.3-6.2). The school water tank was dirty, but this drinking water was qualified as potable. Six stool samples gave positive results for Norovirus. CONCLUSIONS: Norovirus caused this waterborne outbreak of gastroenteritis transmitted through treated drinking water. It should be obligatory to regularly clean school drinking water deposit tanks, especially after the summer holidays.

Factores de riesgo asociados a pacientes tuberculosos con microscopía del esputo positiva / Risk factors associated to tuberculosis patients with positive sputum microscopy

Objetivo: El factor determinante para la producción de casos de tuberculosis por transmisión exógena es la existencia de pacientes con baciloscopias positivas. El objetivo de este estudio fue determinar los factores de riesgo asociados a pacientes con microscopía positiva en secreciones respiratorias. Métodos: Se estudiaron los casos incidentes de tuberculosis del período 1992-1998 en la provincia de Lleida. Las variables del estudio fueron: edad, sexo, infección por el VIH, uso de drogas por vía parenteral (UDVP), consumo de alcohol, existencia de cavernas y resultado de la microcopia del esputo. Se calculó la tasa de incidencia por 100.000 personas-año. La asociación de la variable dependiente -caso de tuberculosis con baciloscopia positiva- con el resto de variables independientes se determinó con la odds ratio (ORc, cruda, y ORa, ajustada mediante regresión logística no condicional) con su intervalo de confianza (IC) del 95 por ciento. Resultados: Se detectaron 905 casos nuevos de tuberculosis. La tasa de incidencia del período 1992-1998 decreció desde 38,8 a 30,8. El 44,9 por ciento de los casos (n = 406) presentó una baciloscopia positiva. El riesgo de ser bacilífero se asoció positivamente con la presencia de cavernas en la radiografía de tórax (ORa = 6,8; IC del 95 por ciento, 4,8-9,5), el género masculino (ORa = 1,8; IC del 95 por ciento, 1,3-2,6) y el consumo de alcohol (ORa = 1,6; IC del 95 por ciento, 1,1-2,3) y fue inferior en los menores de 15 años (ORa = 0,2; IC del 95 por ciento, 0,1-0,5) y coinfectados por el VIH (ORa = 0,5; IC del 95 por ciento, 0,3-0,9). Conclusiones: La infección por el VIH implica un reducido impacto en la endemia tuberculosa. El estudio de contactos y la implantación de tratamientos directamente observados se deben considerar no sólo para los coinfectados por el VIH y UDVP, sino para adultos varones, con consumo excesivo de alcohol, especialmente si presentan lesiones cavernosas (AU)

[Risk factors associated to tuberculosis patients with positive sputum microscopy]. / Factores de riesgo asociados a pacientes tuberculosos con microscopía del esputo positiva.

OBJECTIVE: The main factor responsible for producing new cases of tuberculosis by exogen transmission is the existence of Mycobacterium tuberculosis in the sputum of tuberculosis patients. The objective of this study was to determine the risk factors associated to positive smear tuberculosis cases in Lleida (Spain). METHODS: We studied new cases of tuberculosis over the period 1992-1998. The variables considered were: age, gender, coinfection with HIV, injection drug use (IDU), consumption of alcohol, existence of caverns in thorax X-ray, and laboratory results of direct smear examination. We calculated the incidence rates for 100,000 persons-year. The association between the dependent variable case of tuberculosis with positive Mycobacterium tuberculosis smear and the remaining independent variables were assessed obtaining odds ratios (OR) and 95% confidence intervals (CI) (crude cOR and adjusted aOR by non conditional logistic regression). RESULTS: We detected 905 new cases of tuberculosis. The rates in the period 1992-1998 decreased from 38.8 to 30.8. 44.9% of cases (n = 406) presented a positive direct smear. There was a positive association between the risk of being a positive smear patient and having caverns in thorax x-ray (aOR = 6.8; 95% CI, 4.8-95), being male (aOR = 1.8; 95% CI, 1.3-2.6) and consuming alcohol (aOR = 1.6; 95% CI,1.1-2.3) and this risk was significant lower in those under 15 years old (aOR = 0.2; 95% CI, 0.1-0.5), and coinfection with HIV (aOR = 0.5; 95% CI, 0.3-0.9). CONCLUSIONS: HIV infection implies a reduced impact in endemecity of tuberculosis. Study of contacts and the implementation of directly observed treatment must be considered not only for coinfected HIV cases and IDU but also for adult males, especially those who consume alcohol, particularly when they have caverns.

[Norwalk virus-like food poisoning after eating oysters]. / Toxiinfección alimentaria por ostras causada por virus Norwalk-like.

BACKGROUND: The aim of this study was to conduct a clinical-epidemiological and microbiological investigation into an outbreak of food-borne disease due to the consumption of oysters. PATIENTS AND METHODS: A historic cohort study was conducted into the consumption of 15 food items and clinical symptoms. The influence of each foodstuff was assessed by Mantel-Haenzel stratified relative risk (RRM-H) at 95% confidence intervals, and was confirmed by dose-response analysis with a chi 2 test tendency. We investigated sample stools from 5 patients and 2 food-handlers. RESULTS: The overall attack rate was 38.0% (19/50). The median period of incubation was 39.0 h (maxim 62 and minimum 3 h). The symptoms were: fever 17.6% (3/17), diarrhoea 57.9% (11/19), vomits 84.2% (16/19), nausea 89.5% (17/19) and abdominal pain 89.5% (17/19). In stratified analysis, the Mantel-Haenzel method revealed a statistically risk for oysters (RRM-H = 3.3; IC 95%: 1.1-8.7), while the RRM-H value for sea snails was not significant (RRM-H = 2.8; IC 95%: 0.9-41.1). For oyster consumption, the dose-response test was statistically significant (p = 0.005). Examination by electron microscopy revealed small round structured viruses compatible with Norwalk-like virus. The oyster contamination was reported to the public health authority. CONCLUSIONS: This research highlights the usefulness of dose-response analysis in presenting epidemiological evidence, reveals the potential role of oyster consumption in food-borne disease such us Norwalk-like virus and show the need for monitoring production centres and oyster beds in order to prevent further cases of contamination.

Cigarette smoking and male lung cancer risk with special regard to type of tobacco.

BACKGROUND: The mortality rate from lung cancer (LC) increased sharply in Spain between 1957 and 1986. This increase has been related to a previous increase in cigarette smoking. Certain features of cigarette smoking which were frequent among Spanish smokers (use of black tobacco and use of cigarettes without filter) have been related to a higher risk of LC. METHODS: A hospital-based case-control study was conducted between December 1986 and June 1990. The 325 male patients with lung cancer included in the study (cases) were compared with 325 age-matched male controls without LC. Occupation and lifetime tobacco consumption were requested using a structured questionnaire. The LC odds ratios (OR) and 95% CI were estimated with multiple logistic regression. RESULTS: Lung cancer risk increased with cigarette consumption and duration of the habit. After adjusting for lifetime cigarette consumption and for socioeconomic level, LC risk was greater among black tobacco smokers than among exclusive blond tobacco smokers (OR = 5.0, 95% CI: 2.0-12.7); LC risk among long-term (> or =20 years) filter-tipped cigarette users was lower compared to all other smokers (OR = 0.4, 95% CI: 0.2-0.7). CONCLUSIONS: The main results of the study (a higher LC risk among black tobacco users than in exclusive blond tobacco users, and a lower LC risk among long-term filter-tipped cigarette smokers than all other smokers) have been consistent with previous case-control studies and with ecologic studies which took into account past exposure levels.