Risk of tuberculosis among pulmonary tuberculosis contacts: the importance of time of exposure to index cases

INTRODUCTION

The intensity of exposure to index cases of tuberculosis [TB] may increase the risk of TB in their contacts. The aim was to determine TB risk factors among contacts of TB index cases.

METHODS

A cohort study was carried out in the contacts of pulmonary TB cases registered by the epidemiological surveillance network from 01/01/2019 to 06/30/2021. The factors associated with the risk of TB in contacts were determined using the adjusted odds ratio [aOR] and its 95% confidence interval [CI].

RESULTS

From 847 TB cases, 7087 contacts were identified. The prevalence of TB was 2.0% [145/7087] and was higher in < 5 years compared to those ≥ 65 years [4.4% versus 1.2%; p < 0.001], in those exposed ≥ 6 h daily [4%], and < 6 h daily [1.6%] with respect to weekly exposure of < 6 h [0.7%; p < 0.001]. Those contacts exposed ≥ 6 h daily [aOR= 6.9; 95%CI:2.1-22.1], < 5 years [aOR= 8.3; 95%CI:1.8-37.8] and immigrants [aOR= 1.7; 95%CI:1.1-2.7] had a higher risk of TB.

CONCLUSIONS

The risk of TB increases with the time of exposure to the index case and this risk is also higher in < 5 years and immigrants. Contact tracing has a high yield for detecting new cases of TB.

Two successive outbreaks of acute gastroenteritis due to norovirus GII.6 in a holiday camp house

When two outbreaks occur in the same institution within a short period of time, an important health and social concern is generated. Two gastroenteritis outbreaks occurring a week apart in the same facility were reported in Lleida, Spain, in 2018. The objective of this study was to describe the clinical, epidemiological and microbiological investigation carried out and to determine the risk factors. Demographic data, food consumption and symptoms were collected. Health inspections of the facility were carried out. Risk ratio and their 95% confidence intervals were estimated for the implication of each food consumed. The attack rate was 89.7% in the first outbreak and 69.6% in the second outbreak. The most frequent symptoms in the first and second outbreak were abdominal pain (88.5% and 100%, respectively), vomiting (80.8% and 87.5%, respectively) and nausea (69.2% and 81.3%, respectively). The first outbreak was associated with the consumption of a salad and the second with a cheese omelet. Norovirus GII.6 was detected by RT-PCR and sequenced in both groups of students and in the food handlers who prepared the meals. These results highlight the importance of exclusion from work of food handlers with gastroenteritis, the adequate availability of mechanisms for correct hand washing and the correct cleaning of surfaces.

Epidemiology of GII.4 and GII.2 norovirus outbreaks in closed and semi-closed institutions in 2017 and 2018

Norovirus infections are a leading cause of acute gastroenteritis outbreaks worldwide, with genotypes GII.2 and GII.4 being the most prevalent. The aim of this study was to compare the characteristics of GII.2 and GII.4 norovirus outbreaks reported in Catalonia in closed or semi-closed institutions in 2017 and 2018. The epidemiological and clinical characteristics of GII.2 and GII.4 outbreaks were compared using the chi-square test or Fisher's exact test for categorical variables and the Mann-Whitney U test for continuous variables. Odds ratios and their 95% confidence intervals were estimated. 61 outbreaks were reported: GII.4 was the causative agent in 12 outbreaks (30%) and GII.2 in 9 outbreaks (22.5%). GII.2 outbreaks were detected more frequently in schools or summer camps (66.7%) and GII.4 outbreaks in nursing homes (91.7%) (p = 0.01). Ninety-three people were affected in GII.2 outbreaks and 94 in GII.4 outbreaks. The median age was 15 years (range: 1-95 years) in GII.2 outbreaks and 86 years (range: 0-100 years) in GII.4 outbreaks (p < 0.001). Nausea, abdominal pain, and headache were observed more frequently in persons affected by GII.2 outbreaks (p < 0.05). Symptomatic cases presented a higher viral load suggestive of greater transmission capacity, although asymptomatic patients presented relevant loads indicative of transmission capacity.

COVID-19 vaccination coverage and associated factors in seasonal fruit workers in Lleida

Objectives

Seasonal fruit workers are a high-risk group for SARS-COV-2 infection. We aimed to estimate vaccination coverage and factors associated with vaccination in seasonal fruit workers.

Methods

We carried out an anonymous survey of seasonal fruit workers in the 2021 campaign in Baix Segria region and Lleida city (Spain) on vaccination, knowledge and attitudes about the COVID-19 vaccine. Univariate and bivariate descriptive analyses were performed comparing vaccinated versus non-vaccinated. Multivariate analysis was performed using to assess factors associated to vaccination uptake.

Results

We included 286 seasonal workers. The prevalence of confirmed COVID-19 background was 39.5% and overall vaccination coverage was 78.7%. Factors associated with vaccination were age (aOR = 0.96; 95% CI: 0.94-0.99), good knowledge of disease (aOR = 1.87; 95% CI : 1.01-3.47) and having a high-perceived vaccine effectiveness (aOR = 2.94; 95% CI : 1.50-5.73). High vaccination coverage in workers was associated to knowledge (OR = 3.69; 95% CI: 1.61-8.48), safe transport (OR = 2.84; 95% CI: 1.40-5.76) and appropriate housing (OR = 2.62; 95% CI: 1.25-5.46) as important non-pharmacological measures to reduced transmission.

Conclusion

The study confirms the high prevalence of COVID-19 history and moderate vaccination coverage in seasonal fruit workers. Health education programs to improve knowledge about COVID-19 and its vaccination can help improve vaccination uptake.

Impact of the COVID-19 pandemic on contact tracing of patients with pulmonary tuberculosis

Background

The COVID-19 pandemic could have negative effects on tuberculosis (TB) control. The objective was to assess the impact of the pandemic in contact tracing, TB and latent tuberculosis infection (LTBI) in contacts of patients with pulmonary TB in Catalonia (Spain).

Methods

Contact tracing was carried out in cases of pulmonary TB detected during 14 months in the pre-pandemic period (1 January 2019 to 28 February 2020) and 14 months in the pandemic period (1 March 2020 to 30 April 2021). Contacts received the tuberculin skin test and/or interferon gamma release assay and it was determined whether they had TB or LTBI. Variables associated with TB or LTBI in contacts (study period and sociodemographic variables) were analyzed using adjusted odds ratio (aOR) and the 95% confidence intervals (95% CI).

Results

The pre-pandemic and pandemic periods showed, respectively: 503 and 255 pulmonary TB reported cases (reduction of 50.7%); and 4676 and 1687 contacts studied (reduction of 36.1%). In these periods, the proportion of TB cases among the contacts was 1.9% (84/4307) and 2.2% (30/1381) (P = 0.608); and the proportion of LTBI was 25.3% (1090/4307) and 29.2% (403/1381) (P < 0.001). The pandemic period was associated to higher LTBI proportion (aOR = 1.3; 95% CI 1.1–1.5), taking into account the effect on LTBI of the other variables studied as sex, age, household contact and migrant status.

Conclusions

COVID-19 is affecting TB control due to less exhaustive TB and LTBI case detection. An increase in LTBI was observed during the pandemic period. Efforts should be made to improve detection of TB and LTBI among contacts of TB cases.

Effectiveness of maternal pertussis vaccination in protecting newborn: A matched case-control study

INTRODUCTION

The objective was to estimate the effectiveness of maternal pertussis vaccination in protecting infants aged < 2 months.

METHODS

We performed a case-control study. Laboratory-confirmed cases aged <8 weeks at disease onset were identified and 2-4 matched-controls born within ± 15 days of the case were included. Information was obtained from healthcare providers and maternal interviews. Odds ratios (OR) were calculated using multivariable conditional logistic regression. Vaccine effectiveness (VE) was estimated as (1 - OR) × 100%.

RESULTS

47 cases and 124 controls were studied. The mean age (in days) (39.8 ± 12.7 vs. 40.8 ± 13.2), weeks of gestation (38.8 vs. 39.1, p = 0.43) and mean birth weight (3.309 vs. 3.253 kg, p = 0.55) were comparable between cases and controls. Mothers of cases were less frequently vaccinated in the third trimester (59.6% vs. 83.9%, p <0.001). The VE of maternal vaccination in pregnancy was 88.0% (95%CI 53.8% -96.5%), and was slightly higher in those vaccinated before the 32nd week of gestation (88.5% vs 87.8%).

CONCLUSION

Pertussis vaccination in pregnancy is very effective in reducing pertussis in children aged < 2 months. Vaccination before and after the 32nd week of pregnancy are equally effective in reducing the risk of pertussis.

Clinico-epidemiological characteristics of men and women with a new diagnosis of chronic obstructive pulmonary disease: a database (SIDIAP) study

BACKGROUND

The risk of developing Chronic Obstructive Pulmonary Disease (COPD), the associated comorbidities and response to bronchodilators might differ in men and women. The objective of this study was to determine the prevalence of COPD and the clinic-epidemiological characteristics of primary care patients with COPD according to gender.

METHODS

This is a cross-sectional study using electronic healthcare records Catalonia (Spain), during the 01/01/2012-31/12/2017 period. Patients from the SIDIAP database (System for the Development of Research in Primary Care) were included (5,800,000 patients registered in 279 primary care health centres). Clinic-demographic characteristics, comorbidities and blood tests results were collected for each patient. Adjusted OR (ORa) with logistic regression methods were used to determine variables associated with men and women.

RESULTS

From an initial sample of 800,899 people, 24,135 (3%) were considered COPD patients, and 22.9%were women. The most common risk factors in women were bronchiectasis (ORa = 20.5, SD = 19.5-21.6), age > 71 years (ORa = 18.8; SD = 17.3-20.5), cor pulmonale (ORa = 5.2; SD = 4.3-6.7) and lung cancer (ORa = 3.6, SD = 3.2-4.0). Men and women presented the same comorbidities, though the strength of association was different for each gender.

CONCLUSIONS

Patients suffering high comorbidity rates. Comorbidities are similar in men and women, although the strength of association varies according to gender. Women are more susceptible to the harmful effects of smoking and present a higher proportion of bronchiectasis and OSAS.

Diabetes as a risk factor for severe exacerbation and death in patients with COPD: a prospective cohort study

Background

Type 2 diabetes comorbidity is common in patients with COPD. One of the most frequent causes of hospital admission in patients with COPD are exacerbations.

Methods

Prospective cohort study, which included 512 patients with COPD recruited in a primary care centre in Mollerussa (Lleida, Spain). Inclusion criteria were: patients &gt;40 years of age with COPD according to the Global Initiative for Chronic Obstructive Lung Disease. Variables collected were as follows: age, gender, civil status, education level, smoking habit, severity (Global Initiative for Chronic Obstructive Lung Disease), comorbidities (Charlson), history of severe exacerbations, dyspnoea (mMRC), BODEx, EuroQol 5 D and depression (HAD). Logistic regression was used to determine the association of diabetes with risk of hospital admission and death.

Results

Prevalence of diabetes was 25.8%. During the second year of follow up, 18.2% of patients with COPD and diabetes were admitted for exacerbation, in comparison with 8.9% non-diabetic COPD patients. The variables associated with hospital admission were diabetes (ORa=1.54); gender (men, ORa=1.93); age (ORa=1.02); number of hospital admissions during the previous year: 1 (ORa=2.83) or more than one admission (ORa=4.08); EuroQol 5 D (ORa=0.76) and BODEx (ORa=1.24). With the exclusion of BODEx, all these variables were associated with a higher risk of death.

Conclusion

Prevalence of diabetes is high in patients suffering from COPD. COPD patients with diabetes are at higher risk of severe exacerbation and death. The suggested predictive model could identify patients at higher risk so that adequate preventive and therapeutic measures can be implemented.

Mental disorders in chronic obstructive pulmonary diseases

PURPOSE

Anxiety and depression are underdiagnosed in chronic obstructive pulmonary disease (COPD) patients. Few studies have tried to identify their association with hospitalization (severe exacerbation). The objective of this study was to determine whether the anxiety/depression was associated with severe exacerbation.

DESIGN AND METHODS

A prospective cohort study, based on a sample of 512 patients diagnosed with COPD originating from primary care in a rural area in Lleida (Spain) and monitored between November 1, 2012 and October 31, 2014. For each patient, variables of interest were recorded; they were administered the HADS (Hospital Anxiety and Depression Scale) test to determine the possible presence of anxiety/depression, and its association with severe exacerbation was analyzed using a logistic regression model.

FINDINGS

Initially, the prevalence of anxiety/depression was 15.6%. The incidence of global hospitalization in the first year was 8.2% and 11.3% in the second year. In patients with anxiety/depression, it increased to 17.5% in the first year and 18.8% in the second year. In the multivariate regression model, the diagnosis of anxiety/depression almost doubled the risk of hospitalization (OR = 1.94) (p < .041).

PRACTICE IMPLICATIONS

Anxiety and depression are associated with an increased risk of hospitalization. Intervention studies are needed to evaluate the effects of anxiety/depression in the hospitalization.

Prevalence of chronic obstructive pulmonary disease (COPD) not diagnosed in a population with cardiovascular risk factors

BACKGROUND AND OBJECTIVE

The magnitude of undiagnosed COPD in our population with cardiovascular risk factors (CVRF) is unknown. The objective of this study was to estimate the prevalence of undiagnosed COPD and its specific characteristics in a population with CVRF.

MATERIALS AND METHODS

Study the prevalence of COPD in patients with CVRF. Spirometry was performed between 01/01/2015 and 12/31/2016 and the percentage of patients with COPD, who had not previously been diagnosed, was determined. Each patient's variables of interest were recorded; the records of patients who had spirometry showing COPD were checked to confirm whether a diagnosis had been recorded or not. The association of undiagnosed COPD with different independent variables was determined with adjusted odds ratio (aOR) by non conditional logistic regression models.

RESULTS

2,295 patients with CVRF were studied. The overall prevalence of COPD was 14.5%. An underdiagnosis of 73.3% was observed. Newly diagnosed COPD vs. undiagnosed COPD showed to be higher in women (74.1% vs. 36.0%; P=.081), non-smokers (21.3% vs. 12.4%; P=.577), mild cases (GOLD1) (42.6% vs. 32.4%, P=.008) and cases with lower than average HbA1c (5.5% vs. 5.6%; P=.008) and uric acid (5.1mg/dL vs. 5.6mg/dL; P=.011). The variables associated with undiagnosed COPD were: women (aOR=1.27; 95%CI: 0.74-2.17; P=.383); age (aOR=0.94; 95%CI: 0.87-0.99; P=.018); smokers (smoker/non-smoker) (aOR=0.47; 95%CI: 0.22-1.01; P=.054) and HbA1c (%) (aOR=0.45; 95%CI: 0.23-0.88; P=.019).

CONCLUSIONS

The under-diagnosis of COPD is very high. The contact patients aged between 50 and 65 years-old who have CVRF with their health system should be reassessed, and they need to ask for a spirometry.

Factors influencing the spread of pertussis in households: a prospective study, Catalonia and Navarre, Spain, 2012 to 2013

We aimed to investigate transmission rates of pertussis in household contacts of cases and factors associated with transmission. A prospective epidemiological study was conducted in 2012 and 2013 to determine the incidence of pertussis among household contacts of reported cases in Catalonia and Navarre, Spain. An epidemiological survey was completed for each case and contact, who were followed for 28 days to determine the source of infection (primary case) and detect the occurrence of secondary cases. Odds ratios (ORs) were used to estimate the effectiveness of vaccination and chemoprophylaxis in preventing new cases, using the formula (1 − OR) × 100. For the 688 primary cases, a total of 2,852 contacts were recorded. The household transmission rate was 16.1% (459/2,852) and rose according to the age (> 18 years) and lack of immunisation of the primary cases, and also the age (0–18 years), family relationship (siblings and children), lack of vaccination and chemoprophylaxis of contacts. Pertussis vaccine effectiveness in preventing new cases was 65.0% (95% confidence interval (CI): 11.6 to 86.2) for full vaccination (≥ 4 doses) and 59.7% (95% CI: −6.8 to 84.8) for incomplete vaccination (< 4 doses). The effectiveness of chemoprophylaxis was 62.1% (95% CI: 40.3 to 75.9). To reduce household transmission, contacts should be investigated to detect further cases and to administer chemoprophylaxis. The current vaccination status of cases and contacts can reduce household transmission.

Overview of the Impact of Depression and Anxiety in Chronic Obstructive Pulmonary Disease

BACKGROUND

Anxiety and depression are common entities in patients diagnosed with COPD. However, the impact that they have on the exacerbation of illness is scarcely studied.

OBJECTIVE

To determine if the presence of anxiety and depression is associated with a greater risk of frequent exacerbation (≥2 per year) in patients diagnosed with COPD.

PATIENTS AND METHODS

A cohort study that analysed frequent exacerbation and associated factors in 512 patients monitored during 2 years. Exacerbations were defined as events that required antibiotic/s and/or systemic corticosteroids (moderate) or hospitalization (serious). Variables of interest were recorded for each patient, including anxiety and depression (Hospital Anxiety and Depression Scale), and we analysed their association with frequent exacerbation through the adjusted odds ratio (aOR) by means of a logistic regression model.

RESULTS

The prevalence of anxiety/depression at the start of the study was of 15.6%. During the 2 years of monitoring, 77.9% of the patients suffered at least moderate-to-severe exacerbation. 54.1% were frequent exacerbators. Anxiety/depression were strongly associated with moderate-severe frequent exacerbation in the crude analysis (OR_c = 2.28). In the multivariate analysis, the risk factors also associated with frequent exacerbation were being overweight (aOR 2.78); obesity (aOR 3.02); diabetes (aOR 2.56) and the associated comorbidity (BODEx) (ORa = 1.45).

CONCLUSIONS

The prevalence of anxiety/depression in COPD patients is high, and they are relevant risk factors in frequent exacerbation although the effect is lower in the multivariate analysis when adjusting for different variables strongly associated with exacerbation.

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.

[Norovirus outbreaks in hospitals and nursing homes in Catalonia, Spain]

BACKGROUND

The low infectious dose and multiple transmission routes favour the appearance of norovirus outbreaks. The objective of this study was to compare the incidence of norovirus outbreaks in hospitals and nursing homes in Catalonia.

METHODS

A descriptive study of norovirus outbreaks between 15/10/2004 and 30/10/2005 was carried out. An epidemiological survey was completed for each outbreak. Norovirus in clinical samples was determined by PCR techniques. The incidence in each centre and the annual incidence of outbreaks by centre were calculated. Differences were calculated using the chi-square test and the Student's t test, taking a p value of > 0.05 as significant.

RESULTS

Seventeen outbreaks (6 in hospitals and 11 in nursing homes) were detected. The global attack rate was 33.4% (652/1951) and was slightly higher in nursing homes (35.2%) than in hospitals (31.4%). A total of 94.1% (16/17) of outbreaks were caused by person-to-person transmission and only 5.9% (1/17) by foods. The mean number of days between the first and last case was 11.4 (SD = 6.9). The mean duration of symptoms was 2.39 days (SD=1.6), and was higher hospitals, 2.63 (SD=1.7), than in nursing homes, 1.97 (SD=1.7) (p < 0.0001).

CONCLUSIONS

Norovirus is responsible for a large number of outbreaks due to person-to-person transmission. Control should be standardized to reduce the number and duration of outbreaks.

[Tuberculin reaction size in tuberculosis patient contacts]

OBJECTIVE

The purpose of this study was to explore the association between tuberculin reaction size in contacts with positive tuberculin skin test results and a variety of contact and index patient variables.

PATIENTS AND METHODS

We reviewed the contact investigation records for tuberculosis patients identified by the Tuberculosis Prevention and Control Center of Lleida, Spain, over a period of 7 years. Patients with pulmonary and/or extrapulmonary disease were included. Tuberculosis infection had been diagnosed using the Mantoux skin test with 2 tuberculin units of purified protein derivative RT-23, and tuberculosis disease had been detected on the basis of clinical data, chest radiographs, and cultures. We examined the association between tuberculin reaction size and contact age, close contact with index patients with positive sputum smears, and diagnosis of tuberculosis disease in contacts. Associations were analyzed using the chi(2) test for linear trend.

RESULTS

Tuberculin reaction size was 10 mm or greater in 85.9% of the 768 contacts analyzed and 15 mm or greater in 63.8%. The percentage of contacts under 15 years of age (P=.006) who had close contact with an index patient with a positive sputum smear (P=.013) and who were diagnosed with tuberculosis disease (P=.029) increased with tuberculin reaction size.

CONCLUSIONS

We found that larger tuberculin reaction size in contacts with positive tuberculin skin test results was most frequently associated with recent infections in the contact, close contact with an index patient with a positive sputum smear, and diagnosis of tuberculosis disease in the contact.

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.

Enfermedad meningocócica en Cataluña (1990-1997)

BACKGROUND AND OBJECTIVE

We aimed to study the behavior of meningococcal disease in Catalonia during the period 1990-1997, identifying the possible epidemic periods.

MATERIAL AND METHOD

All cases reported to the notifiable disease system which fulfilled the criteria of confirmed or suspected cases during this period were analyzed.

RESULTS

The global incidence rate was 4.8/100,000. The incidence rate for serogroup B was 1.9/100,000 and for serogroup C 0.8/100,000. The disease incidence tended to diminish slightly during the study period, with a constant annual growth of 0.11/100,000. The increased incidence of serogroup C cases in 1996-1997 was associated with an increased incidence in the 10-19 years age group.

CONCLUSIONS

Globally, in the 1990-1997 period, the disease incidence tended to diminish slightly. During the last two years, an increased incidence was observed, mostly due to the increase in the number of serogroup C cases. This fact was associated with a change in the age pattern of cases, which increased in the 10-19 years age group, as observed in other countries and coinciding with epidemic periods or greater meningococcal activity.

Factores asociados a la infección tuberculosa latente en los contactos de pacientes afectados

BACKGROUND

As tuberculosis control programs have reached acceptable levels in the identification and treatment of persons with active tuberculosis, the next step should be to develop methods of preventing new cases. Persons with latent tuberculosis infection (LTI) are considered to have a higher risk of developing active tuberculosis. The objective of this study was to evaluate the prevalence of LTI and its associated factors in the contacts of tuberculosis patients.

METHODS

We studied the contacts of tuberculosis patients who were examined in the Center for Tuberculosis Control and Prevention in Lleida (Spain) from 1991-1997. Factors associated with the index case (demographic, radiographic, bacteriologic and therapeutic) and tuberculin skin test results and demographic data in contacts were collected. Data on HIV infection, injection drug use and alcohol consumption in tuberculosis patients were also collected. The associations were assessed by obtaining crude and adjusted odds ratios.

RESULTS

The prevalence of LTI among contacts was 36.1% (780/2,161). In the multivariate analysis a higher frequency of LTI was detected in contacts older than 14 years (ORa = 3.34; 95% CI, 2.51-4.45), contacts who had a higher degree of exposure to the index case (ORa = 1.96; 95% CI, 1.59-2.42), contacts of pulmonary tuberculosis patients (ORa = 1.54; 95% CI, 1.01-2.35), contacts of patients with a positive sputum smear (ORa = 1.51; 95% CI, 1.15-1.99), contacts of patients with caverns on chest x-ray (ORa = 1.27; 95% CI, 1.01-1.61) and contacts of patients with delayed treatment (ORa = 1.31; 95% CI, 1.05-1.62).

CONCLUSIONS

The overall prevalence of LTI in the contacts of patients with tuberculosis was high. Among the factors studied, delayed treatment in the index case was independently associated with the frequency of LTI in tuberculosis contacts. Measures for the early diagnosis and treatment of tuberculosis should be intensified.

[Analysis of six families with microepidemics detected in the tuberculosis contact tracing]

BACKGROUND AND OBJECTIVE

The aim of the present study was to analyze the characteristics of families with microepidemics of tuberculosis.

PATIENTS AND METHOD

We included family studies examined in the Center for Tuberculosis Control and Prevention of Lleida during the period 1991-97. A microepidemic was defined as the appearance of two or more new cases in the same family study. The association between the detection of new cases among family contacts and the prevalence of tuberculosis infection was analyzed.

RESULTS

Prevalence of families with microepidemics was 1.4% (6/437). Families with microepidemics generated 15 out of 39 newly diagnosed cases (38.5%). We observed a higher prevalence of tuberculosis infection in families with one new case (OR = 1.67; CI 95%, 1.19-2.34) and in families with microepidemics (OR = 2.67; CI 95%, 1.28-5.62).

CONCLUSIONS

Study of microepidemics of tuberculosis is very important because a small percentage of families with microepidemics (1.4%) generate a large number of secondary cases who are diagnosed during the screening of tuberculosis contacts (38.5%).

[Study investigating infection in contacts of tuberculosis patients in a semi-urban area]

INTRODUCTION

The most important factors for establishing priorities in studies of contacts are the bacteriological status of the patient and the degree of exposure of contact persons to the index case. The aim of the present study was to analyze the results of tuberculosis contact tracing and the relationship between these results and the bacteriological situation of the index case and the proximity of exposure.

METHODS

We studied the contacts of tuberculosis cases examined in the Center for Tuberculosis Control and Prevention of Lleida (a city in the autonomous region of Catalonia, Spain) over the period 1991-1997. The Mantoux test with 2 TU of PPD-RT23 was used to identify infected persons. Diagnosis of tuberculosis disease was made on evidence from the clinical situation, chest radiography and bacteriological status. Associations between infection or disease in the contact, and the bacteriological status of the index case and proximity of exposure, were analyzed. The chi-square test was used for statistical analyses; significance was set at a p value of, 0.05. The odds ratio was calculated as a measure of association.

RESULTS

The prevalence of tuberculosis infection among the contacts was 44% (763/1733). Tuberculin conversion was observed in 7.8% of contacts, and 31 new cases of tuberculosis were detected (1.8%). The percentages of tuberculosis infection, tuberculin conversion and case detection were higher among persons exposed to sputum smear-positive patients and among those in close contact with the index case. Contact infection was more highly associated with the bacteriological status of the index case and degree of proximity of exposure when the analysis was restricted to contacts less than 15 years old. Case detection was 4% among close contacts living with a sputum smear-positive patient.

CONCLUSIONS

Investigation into tuberculosis contacts offered a high yield of detection of infected contact persons and new tuberculosis cases, even among contacts of culture-negative pulmonary tuberculosis patients and contacts of extrapulmonary tuberculosis patients.

[Outbreak of foodborne disease by Norwalk-like viruses genogroup II]

BACKGROUND

Our goal was to investigate the epidemiological characteristics and etiology of an outbreak of food-borne disease caused by Norwalk-like viruses, genogroup II.

PATIENTS AND METHOD

We performed a historical cohort study on the consumption of 21 food items and clinical symptoms. We assessed RNA Norwalk-like viruses by RT- PCR in stool samples from 5 patients and 2 food-handlers. The potential involvement of each food item was assessed by relative risk at 95% confidence intervals (CI).

RESULTS

The overall attack rate was 70.0% (7/10). The median incubation period was 35.0 hours. Symptoms included: vomits 85.7% (6/7), fever 85.7% (6/7) and diarrhoea 71.4% (5/7). Four food items were involved [fish (RR = 1.7; CI 95% 0.9-3.3); 'selection of cold meats' (RR = 1.6; CI 95% 0.9-2.7); yoghurt (RR = 1.5; CI 95% 1.0-2.4) and lamb (RR = 1.3; CI 95% 0.6-3.0)]. Three stool sample gave positive results for Norwalk-like viruses genogroup II. Important oversights in food-handlers' work were detected.

CONCLUSIONS

RT-PCR enabled us to confirm the etiology of this outbreak as Norwalk-like viruses genogroup II. Although patients recovered quickly, the outbreak caused considerable public alarm.

[Risk factors associated to tuberculosis patients with positive sputum microscopy]

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]

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.