Barbara Schimmer - Academia.edu (original) (raw)

Papers by Barbara Schimmer

Fems Immunology and Medical Microbiology, Feb 1, 2012

We describe the Q fever epidemic in the Netherlands with emphasis on the epidemiological characte... more We describe the Q fever epidemic in the Netherlands with emphasis on the epidemiological characteristics of acute Q fever patients and the association with veterinary factors. Data from 3264 notifications for acute Q fever in the period from 2007 through 2009 were analysed. The patients most affected were men, smokers and persons aged 40-60 years. Pneumonia was the most common clinical presentation (62% in 2007 and 2008). Only 3.2% of the patients were working in the agriculture sector and 0.5% in the meat-processing industry including abattoirs. Dairy goat farms with Coxiella burnetii-induced abortion waves were mainly located in the same area where human cases occurred. Airborne transmission of contaminated dust particles from commercial dairy goat farms in densely populated areas has probably caused this epidemic. In 2010, there was a sharp decline in the number of notified cases following the implementation of control measures on dairy goat and sheep farms such as vaccination, hygiene measures and culling of pregnant animals on infected farms. In combination with a rise in the human population with antibodies against C. burnetii, these have most likely ended the outbreak. Development of chronic Q fever in infected patients remains an important problem for years to come.

Emerging Infectious Diseases, Mar 1, 2014

Q fever, caused by Coxiella burnetii, is a recognized occupational infection in persons who have ... more Q fever, caused by Coxiella burnetii, is a recognized occupational infection in persons who have regular contact with ruminants. We determined C. burnetii seroprevalence in residents living or working on dairy cattle farms with >50 adult cows and identified risk factors for seropositivity. Serum samples from farm residents, including employees, were tested for C. burnetii IgG and IgM; seroprevalence was 72.1% overall and 87.2%, 54.5%, and 44.2% among farmers, spouses, and children, respectively. Risk factors included farm location in southern region, larger herd size, farm employment, birds in stable, contact with pigs, and indirect contact with rats or mice. Protective factors included automatic milking of cows and fully compliant use of gloves during and around calving. We recommend strengthening general biosecurity measures, such as consistent use of personal protective equipment (e.g., boots, clothing, gloves) by farm staff and avoidance of birds and vermin in stables. Q fever is an occupational zoonosis caused by Coxiella burnetii, a gram-negative bacterium (1). Ruminant farmers, laboratory workers, dairy workers, and veterinarians are at particular risk for infection. Humans usually acquire Q fever by inhalation of C. burnetii aerosolized from contaminated materials originating from infected animals. The primary animal reservoirs responsible for human infections are cattle, sheep, and goats, which can shed C. burnetii in urine, feces, milk, and birth products. Before 2007, the seroprevalence of C. burnetii antibodies within the general population of the Netherlands was 2.4%; keeping ruminants and increasing age were risk factors for seropositivity (2). During 2007-2009, Q fever was a major public health problem in the Netherlands; >4,000 human cases were reported (3). Large-scale interventions primarily targeting small ruminants were used to control the epidemic. In 2008, mandatory vaccination was conducted in a defined cluster area and later nationwide. In 2009-2010, a program was implemented to cull pregnant dairy goats and sheep on farms with C. burnetii-positive animals identified through a national bulk tank milk (BTM) screening (4). Since then, the incidence of acute Q fever cases has diminished substantially (5), but chronic cases still occur (6). No epidemiologic associations between Q fever cases in humans and dairy cattle were identified during this epidemic, nor have any been described in other Q fever outbreaks (7). Nevertheless, recent reports indicate that C. burnetii is widespread among Dutch dairy cattle herds (prevalence 78.6% [ELISA] or 56.6% [PCR] in BTM samples) (8). In 2008, seroprevalence was 16.0% in lactating cows and 1.0% in young animals (8). C. burnetii seroprevalence estimates for dairy cattle farm residents in the Netherlands are outdated, and risk factors associated with seropositivity are seldom studied. This lack of data inhibits accurate assessment of the public health risk. To inform control measures and provide advice for persons living/working on a dairy cattle farm (DCF), we conducted a cross-sectional study to investigate the seroprevalence of C. burnetii antibodies in DCF residents/ workers and identified participant-based and farm-based risk factors for seropositivity. The study was approved by the Medical Ethics Committee of the University Medical Centre Utrecht (no. 09-189/K).

Dit onderzoek werd verricht in opdracht van de nVWA, in het kader project V/330131/01/ZR: Stel in... more Dit onderzoek werd verricht in opdracht van de nVWA, in het kader project V/330131/01/ZR: Stel in samenwerking met de nVWA een Nederlandstalige tekstuele zoönosenrapportage 2009 op. © RIVM 2010 Delen uit deze publicatie mogen worden overgenomen op voorwaarde van bronvermelding: 'Rijksinstituut voor Volksgezondheid en Milieu (RIVM), de titel van de publicatie en het jaar van uitgave'. Staat van zoönosen 2009 | 3 Rapport in het kort Staat van zoönosen 2009 De Staat van zoönosen 2009 geeft een overzicht van de trends in het voorkomen bij mens en dier van verschillende zoönosen. De cijfers zijn gebaseerd op de data die jaarlijks gemeld worden aan de Europese Commissie, in het kader van Directive 2003/99/EC, over de monitoring van zoönosen en zoönotische agentia. Dit betreft de meldingsplichtige zoönosen. Bovendien wordt er in dit rapport aandacht besteed aan een aantal opmerkelijke voorvallen betreffende zoönosen bij mens of dier, zoals bijvoorbeeld koepokken bij kittens en parasieten in kikkerbillen. Het themahoofdstuk gaat over vectoren; geleedpotige overbrengers van infectieziekten.

Research Square (Research Square), Sep 16, 2022

Background To date no standardized methods are used in order to assess the amoebicidal e cacy of ... more Background To date no standardized methods are used in order to assess the amoebicidal e cacy of commercial contact lens solutions for both trophozoites and cysts of Acanthamoeba species. Here we present two methods that are suitable for this purpose: The Spearman-Karber log reduction method and XTT colorimetric assay. Methods Acanthamoeba castellanii (ATCC 50370) and A. polyphaga (ATCC 30461) trophozoites were cultured in peptone-yeast extract-glucose medium. Cysts were developed in Neff's encystement medium for 1 week. Spearman-Karber and XTT colorimetric assay were used to evaluate trophozoite and cystocidal e cacy of multipurpose contact lens solutions (MPS). Results With trophozoites, the Spearman-Karber method gave a log reduction estimate of morphological kill between log 0,83 and log 3,61 of the various contact lens solutions, enabling the differentiation between e cacious and less e cacious solutions. With cysts the maximum log reduction of 2,17 was achieved for all 3 MPS solutions at 8 hours. The XTT colorimetric assay showed reduction in trophozoite metabolic rates between 50 and 100% as provided by an optical density signal. All lens uid solution with a reduction rate > 90% showed residual growth of Acanthamoeba after one week of incubation on nutrient agar covered with Enterobacter aerogenes. Conclusion Both methods give reproducible estimates of amoebicidal e cacy of contact lens solutions, however, XTT colorimetric assay should be followed by an assay for residual growth to test for viable cysts.

Pathogens, Jan 29, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Weekly releases (1997–2007), Nov 11, 2004

An outbreak of Giardia lamblia has been identified in the city of Bergen (approximately 250 000 i... more An outbreak of Giardia lamblia has been identified in the city of Bergen (approximately 250 000 inhabitants), a popular tourist destination on the western coast of Norway.

Weekly releases (1997–2007), Nov 1, 2007

PLOS ONE, Jun 24, 2022

Introduction Several Public Health Services and general practitioners in the Netherlands observed... more Introduction Several Public Health Services and general practitioners in the Netherlands observed an increase in scabies in the Netherlands. Since individual cases of scabies are not notifiable in the Netherlands, the epidemiological situation is mostly unknown. To investigate the scabies incidence in the Netherlands, we described the epidemiology of scabies between 2011 and 2021. Methods Two national data sources were analysed descriptively. One data source obtained incidence data of scabies (per 1,000 persons) of persons consulting in primary care from 2011-2020. The other data source captured the number of prescribed scabicides in the Netherlands from 2011-2021. To describe the correlation between the incidence of diagnoses and the number of dispensations between 2011 and 2020, we calculated a correlation coefficient. Results The incidence of reported scabies has increased by more than threefold the last decade (2011-2020), mainly affecting adolescents and (young) adults. This was also clearly reflected in the fivefold increase in dispensations of scabicide medication during 2011-2021. The incidence and dispensations were at an all-time high in 2021. We found a strong correlation between the reported incidence and the number of dispensations between 2011 and 2020. Conclusions More awareness on early diagnosis, proper treatment and treatment of close contacts is needed.

European Journal of Clinical Microbiology & Infectious Diseases, Jul 10, 2012

The presence of a high phase I IgG antibody titre may indicate chronic infection and a risk for t... more The presence of a high phase I IgG antibody titre may indicate chronic infection and a risk for the transmission of Coxiella burnetii through blood transfusion. The outbreak of Q fever in the Netherlands allowed for the comparison of an enzyme immunoassay (EIA) with the reference immunofluorescence assay (IFA) in a large group of individuals one year after acute Q fever. EIA is 100 % sensitive in detecting high (≥1:1,024) phase I IgG antibody titres. The cost of screening with EIA and confirming all EIA-positive results with IFA is much lower than screening all donations with IFA. This should be taken into account in cost-effectiveness analyses of screening programmes. W. van der Hoek (*) : C. C. H. Wielders : B. Schimmer :

Emerging Infectious Diseases, Dec 1, 2014

BMC Infectious Diseases, Sep 3, 2015

Background: In spring 2008, a goat farm experiencing Q fever abortions ("Farm A") was identified ... more Background: In spring 2008, a goat farm experiencing Q fever abortions ("Farm A") was identified as the probable source of a human Q fever outbreak in a Dutch town. In 2009, a larger outbreak with 347 cases occurred in the town, despite no clinical Q fever being reported from any local farm. Methods: Our study aimed to identify the source of the 2009 outbreak by applying a combination of interdisciplinary methods, using data from several sources and sectors, to investigate seventeen farms in the area: namely, descriptive epidemiology of notified cases; collation of veterinary data regarding the seventeen farms; spatial attack rate and relative risk analyses; and GIS mapping of farms and smooth incidence of cases. We conducted further spatio-temporal analyses that integrated temporal data regarding date of onset with spatial data from an atmospheric dispersion model with the most highly suspected source at the centre. Results: Our analyses indicated that Farm A was again the most likely source of infection, with persons living within 1 km of the farm at a 46 times larger risk of being a case compared to those living within 5-10 km. The spatio-temporal analyses demonstrated that about 60-65 % of the cases could be explained by aerosol transmission from Farm A assuming emission from week 9; these explained cases lived significantly closer to the farm than the unexplained cases (p = 0.004). A visit to Farm A revealed that there had been no particular changes in management during the spring/summer of 2009, nor any animal health problems around the time of parturition or at any other time during the year. Conclusions: We conclude that the probable source of the 2009 outbreak was the same farm implicated in 2008, despite animal health indicators being absent. Veterinary and public health professionals should consider farms with past as well as current history of Q fever as potential sources of human outbreaks.

Weekly releases (1997–2007), Aug 9, 2007

On 29 May 2007, a general practitioner (GP) from a rural village in the province of Noord- Braban... more On 29 May 2007, a general practitioner (GP) from a rural village in the province of Noord- Brabant, in the south of the Netherlands, alerted the municipal health service about an unusual increase in pneumonia cases among adults in his practice.

Epidemiology and Infection, Nov 11, 2015

Extreme rainfall events may cause pluvial flooding, increasing the transmission of several waterb... more Extreme rainfall events may cause pluvial flooding, increasing the transmission of several waterborne pathogens. However, the risk of experiencing clinically overt infections following exposure to pluvial floodwater is poorly estimated. A retrospective cross-sectional survey was performed to quantify the occurrence of self-reported gastrointestinal, influenza-like illness (ILI) and dermatological complaints, and the frequency of visits to the general practitioner (GP), during a 4-week observation period following pluvial flooding at seven locations in The Netherlands. Questionnaires were sent to 817 flooded households, 149 (17%) of which returned the questionnaire reporting information for 199 participants. Contact with floodwater was significantly associated with increased occurrence of gastrointestinal [odds ratio (OR 4•44)], ILI (OR 2•75) and dermatological (OR 6•67) complaints, and GP visits (OR 2•72). Having hand contact with floodwater was associated with gastrointestinal and dermatological complaints, whereas ILI complaints were associated with being engaged in post-flooding cleaning operations and having walked/cycled through floodwater. This study shows that floodwater-associated diseases occur in urban settings following extreme rainfall events in a high-income country. As pluvial floods are expected to escalate in the future due to global climate change, further research is warranted to determine the disease burden of pluvial flooding and to assess the effect of different interventions, including raising awareness among stakeholders.

Epidemiology and Infection, Aug 7, 2013

In this study, Coxiella burnetii seroprevalence was assessed for dairy and non-dairy sheep farm r... more In this study, Coxiella burnetii seroprevalence was assessed for dairy and non-dairy sheep farm residents in The Netherlands for 2009-2010. Risk factors for seropositivity were identified for non-dairy sheep farm residents. Participants completed farm-based and individual questionnaires. In addition, participants were tested for IgG and IgM C. burnetii antibodies using immunofluorescent assay. Risk factors were identified by univariate, multivariate logistic regression, and multivariate multilevel analyses. In dairy and non-dairy sheep farm residents, seroprevalence was 66•7% and 51•3%, respectively. Significant risk factors were cattle contact, high goat density near the farm, sheep supplied from two provinces, high frequency of refreshing stable bedding, farm started before 1990 and presence of the Blessumer breed. Most risk factors indicate current or past goat and cattle exposure, with limited factors involving sheep. Subtyping human, cattle, goat, and sheep C. burnetii strains might elucidate their role in the infection risk of sheep farm residents.

Epidemiology and Infection, Nov 19, 2010

Data about the effectiveness of different antibiotic regimens for the treatment of acute Q fever ... more Data about the effectiveness of different antibiotic regimens for the treatment of acute Q fever from clinical studies is scarce. We analysed the antibiotic treatment regimens of acute Q fever patients in 2007 and 2008 in The Netherlands and assessed whether hospitalization after a minimum of 2 days antibiotic therapy was related to the initial antibiotic therapy. Clinical data on antibiotic treatment and risk factors of acute Q fever patients were obtained from general practitioner medical records and self-reported by patients. For the 438 study patients, doxycycline was the most commonly prescribed initial antibiotic in both study years. After adjustments for confounding factors, doxycycline (200 mg/day), moxifloxacin, as well as other possibly effective antibiotics [including other new fluoroquinolones and doxycycline (100 mg/day)] showed significant lower risks for hospitalization compared to b-lactam antibiotics and azithromycin (reference group), with the lowest risk for doxycycline (200 mg/day) (odds ratio 0. 04, 95 % confidence interval 0. 01-0. 22). These data support current guidelines that recommend doxycycline as the first choice antibiotic for treating acute Q fever.

Epidemiology and Infection, Feb 16, 2011

The Netherlands has experienced large community outbreaks of Q fever since 2007. Sera and questio... more The Netherlands has experienced large community outbreaks of Q fever since 2007. Sera and questionnaires containing epidemiological data from 5654 individuals were obtained in a nationwide seroprevalence survey used to evaluate the National Immunization Programme in 2006-2007. We tested these sera for IgG phase-2 antibodies against Coxiella burnetii with an ELISA to estimate the seroprevalence and to identify determinants for seropositivity before the Q fever outbreaks occurred. Overall seroprevalence was 1. 5 % [95 % confidence interval (CI) 1. 3-1. 7]. Corrected for confirmation with immunofluorescence results in a subset, the estimated seroprevalence was 2. 4%. Seropositivity ranged from 0. 48% (95 % CI 0. 00-0. 96) in the 0-4 years age group to 2. 30% (95 % CI 1. 46-3. 15) in the 60-79 years age group. Keeping ruminants, increasing age and being born in Turkey were independent risk factors for seropositivity. The low seroprevalence before the start of the outbreaks supports the hypothesis that The Netherlands has been confronted with a newly emerging Q fever problem since spring 2007.

Applied and Environmental Microbiology, Mar 15, 2012

Eurosurveillance, Dec 11, 2008

, an outbreak of Shiga toxin-producing Escherichia coli (STEC) O157 simultaneously occurred in th... more , an outbreak of Shiga toxin-producing Escherichia coli (STEC) O157 simultaneously occurred in the Netherlands and Iceland. A total of 50 laboratoryconfirmed cases were reported with a STEC O157 infection caused by the same clone. The strain was of type O157:H-, PT8, positive for stx 1 , stx 2 , eae and e-hly, and sorbitol negative. The most probable cause of this international outbreak was contaminated lettuce, shredded and pre-packed in a Dutch food processing plant. Samples of the environment, raw produce and end products, taken at several vegetable growers and processing plants all tested negative for STEC O157. However, the only epidemiological link between the cases in the Netherlands and in Iceland was the implicated Dutch processing plant. In Europe, food products are often widely distributed posing the risk of potential spread of food borne pathogens simultaneously to several countries. This international outbreak emphasises the importance of common alert and surveillance systems in earlier detection of international outbreaks and better assessment of their spread.

Eurosurveillance, Jul 23, 2015

prophylaxis of contacts was performed. The outbreak highlighted how large food-borne hepatitis A ... more prophylaxis of contacts was performed. The outbreak highlighted how large food-borne hepatitis A outbreaks may affect the increasingly susceptible EU/EEA general population and how, with the growing international food trade, frozen berries are a potential highrisk food.