Background. Acute respiratory tract infections (ARTIs) are responsible for considerable morbidity in the community, but little is known about the presence of respiratory pathogens in asymptomatic ...individuals. We hypothesized that asymptomatic persons could have a subclinical infection and thus act as a source of transmission. Methods. During the period of 2000–2003, all patients with ARTI who visited their sentinel general practitioner had their data reported to estimate the incidence of ARTI in Dutch general practices. A random selection of these patients (case patients) and an equal number of asymptomatic persons visiting for other complaints (control subjects) were included in a case-control study. Nose and throat swabs of participants were tested for a broad range of pathogens. Results. The overall incidence of ARTI was 545 cases per 10,000 person-years, suggesting that, in the Dutch population, an estimated 900,000 persons annually consult their general practitioner for respiratory complaints. Rhinovirus was most common in case patients (24%), followed by influenza virus type A (11%) and coronavirus (7%). Viruses were detected in 58% of the case patients, β-hemolytic streptococci group A were detected in 11%, and mixed infections were detected in 3%. Pathogens were detected in ∼30% of control subjects, particularly in the youngest age groups. Conclusion. This study confirms that most ARTIs are viral and supports the reserved policy of prescribing antibiotics. In both case and control subjects, rhinovirus was the most common pathogen. Of bacterial infections, only group A β-hemolytic streptococci were more common in case patients than in control subjects. Furthermore, we demonstrated that asymptomatic persons might be a neglected source of transmission.
A prospective population-based cohort study with a nested case-control study was conducted to estimate the incidence of gastroenteritis and the associated pathogens in the general Dutch population. ...Follow-up of two consecutive cohorts was performed by weekly reporting cards from December 1998 to December 1999. Cases and controls in the case-control study supplied a questionnaire and stool samples. The standardized gastroenteritis incidence was 283 per 1,000 person-years. The incidence rose with increasing level of education and was higher for persons with a history of diarrhea and for young children. Bacterial pathogens accounted for 5% of cases, bacterial toxins for 9%, parasites for 6%, and viral pathogens for 21%, with Norwalk-like virus (NLV) as the leading pathogen in 11% of cases. The gastroenteritis incidence was higher than that reported for England, but lower than for the United States. In community cases, viral pathogens are the leading cause of gastroenteritis, with NLV being the number one cause of illness in all age groups but one. In many countries, preventive measures are implemented to decrease bacterial infections. However, additional prevention of viral infections, especially NLV, might significantly decrease the number of gastroenteritis cases in the community.
Objective: This Dutch epidemiological study used primary care-based data to examine changes in the incidence of eating disorders in the 1990s compared to the 1980s. Method: A nationwide network of ...general practitioners, serving a representative sample of the total Dutch population, recorded newly diagnosed patients with anorexia nervosa (AN) and bulimia nervosa (BN) in their practices during 1985-1989 and 1995-1999. Results:The overall incidence of AN was stable (from 7.4 to 7.7 per 100,000). However, the incidence among 15-19-year-old females increased significantly (from 56.4 to 109.2 per 100,000). The incidence rate of BN decreased nonsignificantly from 8.6 to 6.1 per 100,000. Conclusion: The time trend of an increasing AN incidence among the high risk group continued to the end of the past century. The BN incidence did not rise as was expected.
Objectives: Urinary tract infections (UTIs) are common bacterial infections encountered in general practice. For the optimal treatment the general practitioner (GP) should rely on the results of ...diagnostic tests and recent antimicrobial susceptibility of uropathogens. Patients and methods: In total 1993 female patients (11–70 years) with complaints of an acute uncomplicated UTI were included. The performance characteristics of the diagnostic tests used were determined and compared with the antibiotic prescription rate. The antibiotic therapy (agent and duration), the uropathogens and the antibiotic susceptibility of Escherichia coli were determined for each age group. Results: The positive predictive value (PPV) (96%) and the specificity (94%) of the nitrite test were high for all samples. A negative nitrite with a positive leucocyte-esterase (LE) test showed a high PPV (79%) and sensitivity (82%). When both nitrite and LE tests were negative ∼50% of the samples were culture positive. Of the patients, 94% of those with a positive nitrite test and 71% of those with a negative nitrite and positive LE test were prescribed antibiotics, mostly nitrofurantoin and trimethoprim. Nitrofurantoin prescriptions decreased and those of fluoroquinolones increased with increasing age. Nitrofurantoin was equally prescribed for 3–7 days in all patients. Trimethoprim was mostly prescribed for 3 days in patients aged 21–50 years and for 5 days in the other patients. E. coli, the uropathogen mostly isolated, decreased in frequency with increasing age. Proteus mirabilis was found more in the oldest patients and Staphylococcus saprophyticus in the younger patients. The antimicrobial susceptibility of E. coli was not age related. The lowest percentages were found for amoxicillin (67%) and trimethoprim (77%). Fluoroquinolone resistance was emerging in the older patients. Conclusions: For female patients with symptoms of an acute uncomplicated UTI a positive nitrite test or a negative nitrite test with a positive LE test confirmed UTI whereas a negative nitrite together with a negative LE test did not rule out infection. For empirical treatment GPs should take into account the changing aetiology with increasing age. Prudent use of antibiotics in general and more specificly fluoroquinolones remains recommended. As trimethoprim resistance reached 20% it might be advisable to no longer use it as therapy of first choice for acute uncomplicated UTIs in The Netherlands.
We compared gastroenteritis cases that consulted a general practitioner (GP) with those who did not in a community-based study and also with those in a GP-based study. We aimed to identify factors ...associated with consultation, and with inclusion of cases by GPs, and secondly to study the effects on the frequency of detection of pathogens. Furthermore, we estimated the under-ascertainment by GPs. Both studies were performed in The Netherlands in the same population in an overlapping time-period. Overall, 5% of community cases consulted a GP. Cases who consulted suffered from more severe episodes than non-consulting cases. Inclusion of cases by GPs, instead of a study team, caused a selection of more severe cases with more chronic symptoms. When extrapolating data from GP-based studies, it should be taken into account that, in general practice, gastroenteritis due to bacteria and Giardia lamblia is a relatively large proportion of that in the community and gastroenteritis due to Norwalk-like viruses is a relatively small proportion. The incidence of gastroenteritis in general practices was estimated between 14 and 35 per 1000 person years.
During a 30-month prospective study in The Netherlands, the distribution of Mycoplasma pneumoniae and respiratory viruses among 1172 patients with acute respiratory infection (ARI) who were treated ...in the outpatient general practitioner setting was studied. M. pneumoniae, as detected by polymerase chain reaction analysis, was present in 39 (3.3%) patients. The infection rate was similar in all age groups. Nose and throat samples collected from 79 household contacts of M. pneumoniae-positive index patients revealed M. pneumoniae in 12 (15%) cases. The frequency of M. pneumoniae among household contacts of index patients treated with appropriate antibiotics and untreated index patients was similar. Nine of the 12 M. pneumoniae-positive household contacts were <16 years old (P = .02), and 4 (44%) of them did not develop ARI. Apparently, children are a relevant reservoir for M. pneumoniae.
The link between degree of urbanisation and a number of mental disorders is
well established. Schizophrenia, psychosis and depression are known to occur
more frequently in urban areas. In our primary ...care-based study of eating
disorders, the incidence of bulimia nervosa showed a dose–response relation
with degree of urbanisation and was five times higher in cities than in
rural areas. Remarkably, anorexia nervosa showed no association with
urbanisation. We conclude that urban life is a potential environmental risk
factor for bulimia nervosa but not for anorexia nervosa. These findings
provide a promising avenue for further research into the aetiology of eating
disorders.
Weekly incidence data for influenza-like illness, routinely collected in sentinel general practices in England and Wales and in the Netherlands over 10 winter periods (week 37 in one year to week 20 ...in the next, 1987/1988-1996/1997) were examined in conjunction with matching virus isolate data to define epidemic periods of influenza in the two countries. We first defined the background rates of recording influenza-like illness which occurred at times when only sporadic or no isolations of virus were reported. The background rates were similar in the two networks with mean weekly incidence in England and Wales of 28.1 per 100,000 (all ages) and in the Netherlands 29.8. Epidemic periods defined as lying above the upper 95% confidence level of the background rate lasted on an average of about 10 weeks. Once epidemics were recognised, peak incidence was generally achieved within 4 weeks. The excess population (all ages) consulting general practitioners during influenza epidemic periods was calculated from the difference between the observed and background incidence rates, and expressed as a percentage of the total population. In the 10 periods surveyed, the percentage of the population consulting and diagnosed with influenza-like illness in England and Wales ranged from 0.4% in 1991/1992 to 1.7% in 1989/1990 and in the Netherlands from 0.5% in 1990/1991 to 2.1% in 1989/1990. The duration and epidemic periods were broadly similar in the two countries though the excess consulting population during the 10 epidemics studied averaged 0.85% in England and Wales compared with 1.39% in the Netherlands. There were substantial differences between the two countries in the impact of influenza in individual years, as measured in the consulting population even though the predominant virus (sub)types were similar.
A population-based study was conducted among women over the age of 70 years with complaints of uncomplicated urinary tract infections (UTIs). The positive predictive value of the nitrite test alone ...or in combination with the leukocyte esterase test ranged between 83% and 99%. The nitrofurantoin prescription rate decreased whereas fluoroquinolone and amoxicillin/clavulanic acid prescriptions increased with increasing age. The aetiology of infection was age-dependent.
Escherichia coli was the most commonly isolated uropathogen, followed by
Proteus mirabilis and
Klebsiella pneumoniae. For these uropathogens, the lowest susceptibility percentages were found for amoxicillin, trimethoprim and co-trimoxazole. As trimethoprim susceptibility reached ∼75%, it may be advisable not to use this as a first-choice agent in the treatment of uncomplicated UTIs in the elderly.
Acute respiratory tract infections (ARTI) are an important public health problem. Improved identification of risk factors might enable targeted intervention. Therefore we carried out a case-control ...study with the aim of identifying environmental risk factors for ARTI consultations in the Dutch general population.
A subset of patients visiting their GP in the period of 2000-2003 with an ARTI (cases) and age-matched controls (visiting for other complaints) were included in a case-control study. They were asked to complete a questionnaire about potential risk factors. Conditional logistic regression was used to calculate odds ratio's (OR) and 95% confidence intervals (CI) to estimate the independent effect of potential risk factors.
A total of 493 matched pairs of case and control subjects were enrolled. Exposure to persons with respiratory complaints, both inside and outside the household, was found to be an independent risk factor for visiting a GP with an ARTI (respectively ORadj = 1.9 and ORadj = 3.7). Participants exposed to dampness or mould at home (ORadj=0.5) were significantly less likely to visit their GP. In accordance with the general risk of consultations for ARTI, participants with a laboratory-confirmed ARTI who were exposed to persons with respiratory complaints outside the household were also significantly more likely to visit their GP (ORadj=2.5).
This study confirmed that heterogeneity in the general population as well as in pathogens causing ARTI makes it complicated to detect associations between potential risk factors and respiratory infections. Whereas it may be difficult to intervene on the risk posed by exposure to persons with respiratory complaints, transmission of ARTI in the general population might be reduced by improved hygienic conditions.
PDF
