Ralf Reintjes

Tularemia Outbreak Investigation in Kosovo: Case Control and Environmental Studies

A large outbreak of tularemia occurred in Kosovo in the early postwar period, 1999-2000. Epidemiologic and environmental investigations were conducted to identify sources of infection, modes of transmission, and household risk factors. Case and control status was verified by enzyme-linked immunosorbent assay, Western blot, and microagglutination assay. A total of 327 serologically confirmed cases of tularemia pharyngitis and cervical lymphadenitis were identified in 21 of 29 Kosovo municipalities. Matched analysis of 46 case households and 76 control households suggested that infection was transmitted through contaminated food or water and that the source of infection was rodents. Environmental circumstances in war-torn Kosovo led to epizootic rodent tularemia and its spread to resettled rural populations living under circumstances of substandard housing, hygiene, and sanitation.

Automated DNA Sequence-Based Early Warning System for the Detection of Methicillin-Resistant Staphylococcus aureus Outbreaks

Background The detection of methicillin-resistant Staphylococcus aureus (MRSA) usually requires the implementation of often rigorous infection-control measures. Prompt identification of an MRSA epidemic is crucial for the control of an outbreak. In this study we evaluated various early warning algorithms for the detection of an MRSA cluster. Methods and Findings Between 1998 and 2003, 557 non-replicate MRSA strains were collected from staff and patients admitted to a German tertiary-care university hospital. The repeat region of the S. aureus protein A (spa) gene in each of these strains was sequenced. Using epidemiological and typing information for the period 1998–2002 as reference data, clusters in 2003 were determined by temporal-scan test statistics. Various early warning algorithms (frequency, clonal, and infection control professionals [ICP] alerts) were tested in a prospective analysis for the year 2003. In addition, a newly implemented automated clonal alert system of the Ridom StaphType software was evaluated. A total of 549 of 557 MRSA were typeable using spa sequencing. When analyzed using scan test statistics, 42 out of 175 MRSA in 2003 formed 13 significant clusters (p < 0.05). These clusters were used as the “gold standard” to evaluate the various algorithms. Clonal alerts (spa typing and epidemiological data) were 100% sensitive and 95.2% specific. Frequency (epidemiological data only) and ICP alerts were 100% and 62.1% sensitive and 47.2% and 97.3% specific, respectively. The difference in specificity between clonal and ICP alerts was not significant. Both methods exhibited a positive predictive value above 80%. Conclusions Rapid MRSA outbreak detection, based on epidemiological and spa typing data, is a suitable alternative for classical approaches and can assist in the identification of potential sources of infection.

Communicable disease control handbook

Section 1 - introduction section 2 - common topics section 3 - diseases section 4 - services and organization section 5 - communicable disease control in individual countries appendices - resources for the CCDC.

Changing epidemiology of Hepatitis B and migration—a comparison of six Northern and North-Western European countries

BACKGROUND Increased migration volume and different Hepatitis B prevalence between immigration and emigration countries have changed the Hepatitis B virus (HBV) epidemiology considerably in Northern and North-Western European migrants-receiving countries. Due to the difference in migration status monitoring, the HBV infection data on migrants are not easily comparable among those countries. The study aims were: to compare the migration status indicators used by the national surveillance system in six Northern and North-Western European countries (the Netherlands, Germany, Finland, Denmark, Sweden and the UK); to determine the impact of the migration status on HBV infection by comparing the available data on prevalence and transmission routes of Hepatitis B in the migration and the general population in the six countries; to recommend sensible indicators and pertinent measures for HBV infection surveillance and control in the region. METHODS Literature review, statistical data analysis on migration and HBV infection in the six countries; expert interviews to identify migration status indicators used in national surveillance systems. RESULTS Evident differences were found between the migration and the general population in Hepatitis B prevalence and transmission routes in the six countries. Migration status is monitored differently in six surveillance systems; immigrants from high/intermediate Hepatitis B endemic countries constitute a substantial proportion of HBsAg(+) and chronic cases in all six countries. CONCLUSIONS International migration has an obvious impact on Hepatitis B prevalence in the six countries. It is important to include common migration status indicators and to collect comparable data for HBV infection surveillance in different notification systems.

Spatial patterns of diarrhoeal illnesses with regard to water supply structures--a GIS analysis.

This paper presents an application of a geographical information system (GIS) in the field of research of drinking water epidemiology. A retrospective study regarding gastrointestinal infections was carried out in the Rhine-Berg District (North Rhine-Westphalia, Germany), which is characterised by different drinking water supply structures. The main objective was to examine the hypothesis that spatial variations of diarrhoeal illnesses may be linked with different drinking water sources (groundwater or surface water). We introduced a GIS for storing and analysing the wide range of data sets comprising features of the water supply structure and the epidemiological databases which constitute the basic elements of a surveillance-system for waterborne infectious diseases. GIS-techniques supported the generation of hypotheses regarding disease distribution and causation. The data bases which are routinely available turned out to be of sufficient quantity and quality for running a waterborne disease surveillance-system. Geo-statistical analysis revealed spatial variations in the incidence of diarrhoeal illnesses. Parameters depicting the water supply structures, especially the amount of drinking water produced from surface or groundwater, were correlated with the age-standardised incidence rates of gastrointestinal infections. The correlation models showed a trend of positive linkage between disease incidence and amount of groundwater. We found GIS-techniques extremely useful to carry out area-based correlation studies and to analyse the exposure of populations in drinking water epidemiology.

Meningococcal carriage in relation to an outbreak of invasive disease due to Neisseria meningitidis serogroup C in the Netherlands

BACKGROUND a cross-sectional study on meningococcal carriage was performed in Putten, a small rural town in the Netherlands where an unusual high incidence of invasive meningococcal disease (IMD) due to Neisseria meningitidis C:2a:P1.5 occurred. The outbreak was controlled by mass vaccination of all inhabitants aged 2 to 20 years. METHODS meningococcal carriage was studied in three groups: (1) a systematic age-specific sample of 2-20 year olds who visited the immunization clinic in Putten (January 1998: n=411); (2) children and adolescents in the same age range recruited through a kindergarten and schools in Venlo, a town where the causative strain of IMD had not been encountered (February 1998; n=374); (3) all initial carriers in Putten and a sample of non-carriers in that town (March 1998: n=145). Oropharyngeal swabs were taken for the purpose of isolating N. menigitidis. RESULTS the prevalence of carriage was 12.4% in Putten and 18.2%, in Venlo, but the prevalence of group C meningococci was higher in Putten (1.7%) than Venlo (0.5%). N. meningitidis C:2a:P1.5 was isolated twice in Putten and not at all in Venlo. A second examination in Putten showed that 18 of the 22 repeatedly tested carriers were still carriers, and six new carriers were found among the 55 initial non-carriers. Of the two known carriers of C:2a:P1.5, one was still carrying the same strain, and the other did not participate in the second investigation. Carriage was associated with increasing family size, discotheque visits and visits to youth clubs and sports clubs. In contrast, visits to the swimming pool appeared to be related to a lower risk, as was recent antibiotic use. CONCLUSION the prevalence of carriage with the invasive strain C:2a:P1.5 was low in the population that experienced a community-wide outbreak recently: the specific strain was not found in the reference population. This indicates a relatively high risk of developing the invasive disease for those who become infected with such strains.

Simpson's paradox : An example from hospital epidemiology

Simpsons paradox was first recognized at the beginning of the 20th century, but few examples with real data have been presented. In this paper we present an example of this phenomenon from a multicenter study on nosocomial infections, and we try to explain intuitively this type of extreme confounding.

Community-wide outbreak of enteroviral illness caused by echovirus 30: a cross-sectional survey and a case-control study.

BACKGROUND In June, 1997, 21 children from a single community in Germany were hospitalized with aseptic meningitis. An epidemiologic investigation was conducted to determine the extent of the outbreak and risk factors for illness. METHOD The extent of the outbreak was assessed with a cross-sectional survey of every 10th child listed in the town register among the 2240 town children < 16 years old. A case-control study determined risk factors for illness. Sixty-two cases were identified through the cross-sectional survey from hospitalized persons and from persons seen by local physicians. Controls were 114 asymptomatic persons identified from the cross-sectional survey. RESULTS The overall attack rate was 16%, with the highest attack rates (24%) among the 6- to 8-year olds. Onsets occurred during a 37-day period. Among the 2240 town children <16 years of age, an estimated 353 met the case definition for enteroviral illness, 168 visited a doctor and 21 were hospitalized. Data from the case-control study indicated that contact with an ill household member [odds ratio (OR) = 6.3; 95% confidence interval (CI) 2.6 to 15.5], day-care attendance (OR = 2.6; 95% CI 1.1 to 6.2) and playground use, either two to three times per week (OR = 3.7; 95% CI 1.3 to 10.2) or daily (OR = 4.3; 95% CI 1.6 to 11.3), were risk factors for illness. CONCLUSION Echovirus 30 caused substantial morbidity during this community outbreak caused by person-to-person spread. Household contacts, day-care centers and playgrounds were prominent risk factors for transmission.

Health System Resource Gaps and Associated Mortality from Pandemic Influenza across Six Asian Territories

Background Southeast Asia has been the focus of considerable investment in pandemic influenza preparedness. Given the wide variation in socio-economic conditions, health system capacity across the region is likely to impact to varying degrees on pandemic mitigation operations. We aimed to estimate and compare the resource gaps, and potential mortalities associated with those gaps, for responding to pandemic influenza within and between six territories in Asia. Methods and Findings We collected health system resource data from Cambodia, Indonesia (Jakarta and Bali), Lao PDR, Taiwan, Thailand and Vietnam. We applied a mathematical transmission model to simulate a “mild-to-moderate” pandemic influenza scenario to estimate resource needs, gaps, and attributable mortalities at province level within each territory. The results show that wide variations exist in resource capacities between and within the six territories, with substantial mortalities predicted as a result of resource gaps (referred to here as “avoidable” mortalities), particularly in poorer areas. Severe nationwide shortages of mechanical ventilators were estimated to be a major cause of avoidable mortalities in all territories except Taiwan. Other resources (oseltamivir, hospital beds and human resources) are inequitably distributed within countries. Estimates of resource gaps and avoidable mortalities were highly sensitive to model parameters defining the transmissibility and clinical severity of the pandemic scenario. However, geographic patterns observed within and across territories remained similar for the range of parameter values explored. Conclusions The findings have important implications for where (both geographically and in terms of which resource types) investment is most needed, and the potential impact of resource mobilization for mitigating the disease burden of an influenza pandemic. Effective mobilization of resources across administrative boundaries could go some way towards minimizing avoidable deaths.

Communicable disease outbreaks involving more than one country: systems approach to evaluating the response

The growth in international trade and travel has increased the likelihood that outbreaks of infection will involve more than one country. The response to such an international epidemiological emergency is complex, involving national and international agencies. We evaluated responses to five outbreaks, with various transmission routes, involving more than one member state of the EU. We examined the complex nature of the collaboration required for an effective response and identified critical weaknesses in coordination, funding, and reporting. #### Summary points Increasing international trade and travel have led to concern that there will be outbreaks of infection involving more than one country The detection of and response to international outbreaks needs to be international and coordinated An analysis of the response to several international outbreaks has shown inadequacies in detection, coordination, funding, and reporting Support for disease surveillance and control in less developed countries should be expanded to strengthen global surveillance We studied five past outbreaks, selected primarily to capture different routes of disease transmission (table). We compiled these case studies using various data sources.8 Over 50 semistructured interviews were undertaken to determine what happened, what should have happened, why the difference, and what improvements could be made. Interviewees were selected through the relevant European disease surveillance network(s), member states national communicable disease surveillance centres, the World Health Organization, and the Centers for Disease Control and Prevention (Atlanta, United States). The snowball method9 identified further interviewees. We reviewed published and unpublished material. View this table: Selected case studies We undertook a postal survey with questions on preparedness for an influenza pandemic in Europe and the role of the European Programme for Intervention Epidemiology Training in international incidents. Our analyses included techniques of …