Publications (120) View all
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Article: Coxiella burnetii in sewage water at sewage water treatment plants in a Q fever epidemic area.
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ABSTRACT: During 2007-2010, over 4000 persons in The Netherlands contracted Q-fever, a zoonosis caused by the bacterium Coxiella burnetii. Goats and sheep are the main reservoir of C. burnetti and infected animals shed the bacterium with their urine, faeces and birth products. Human infections may occur through direct contact with infected animals, or through inhalation of contaminated dust particles or aerosols. Discharge of waste water from Q fever contaminated goat farms may result in the presence of C. burnetii in sewage water and aerosols at sewage water treatment plants (SWTPs) which may pose a health risk for workers or neighbouring residents. The objectives of this study were to determine the presence of C. burnetii at SWTPs and to optimize available detection methods. In March-July 2011, sewage influent and aeration tank samples from four SWTPs receiving discharge from Q fever positive goat farms were examined by using a multiplex real-time PCR detecting C. burnetii DNA by targeting IS1111 and com1 genes. Influent (44%; n=16/36) and active sludge (36%; n=13/36) samples were positive with low C. burnetii DNA content. Percentage positive samples per SWTP were 28-61%. Positive samples were most frequent in March 2011 and least frequent in May 2011. The presence of C. burnetii DNA in sewage water samples suggests that SWTPs receiving waste water from Q fever contaminated goat farms may contribute to the spread of C. burnetii to the environment. The low levels of C. burnetii DNA in sewage water during the decline of the Q fever outbreak in The Netherlands in 2011 indicate a low health risk for SWTP workers and residents.International journal of hygiene and environmental health 01/2013; · 2.64 Impact Factor -
Article: Differential coreceptor expression allows for independent evolution of non-syncytium-inducing and syncytium-inducing HIV-1
The Journal of clinical investigation 01/2001; 106(12):1569. · 15.39 Impact Factor -
Article: Rapid virus detection procedure for molecular tracing of shellfish associated with disease outbreaks.
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ABSTRACT: Detection of pathogenic viruses in oysters implicated in gastroenteritis outbreaks is often hampered by time-consuming, specialist virus extraction methods. Five virus RNA extraction methods were evaluated with respect to performance characteristics and sensitivity on artificially contaminated oyster digestive glands. The two most promising procedures were further evaluated on bioaccumulated and naturally contaminated oysters. The most efficient method was used to trace the source in an outbreak situation. Out of five RNA extraction protocols, PEG precipitation and the RNeasy Kit performed best with norovirus genogroup III-spiked digestive glands. Analyzing 24-h bioaccumulated oysters revealed a slightly better sensitivity with PEG precipitation, but the RNeasy Kit was less prone to concentrate inhibitors. The latter procedure demonstrated the presence of human noroviruses in naturally contaminated oysters and oysters implicated in an outbreak. In this outbreak, in four out of nine individually analyzed digestive glands, norovirus was detected. In one of the oysters and in one of the fecal samples of the clinical cases, identical norovirus strains were detected. A standard and rapid virus extraction method using the RNeasy Kit appeared to be most useful in tracing shellfish as the source in gastroenteritis outbreaks, and to be able to make effective and timely risk management decisions.Journal of food protection 05/2007; 70(4):967-74. · 1.94 Impact Factor -
Article: The course of hepatitis E virus infection in pigs after contact-infection and intravenous inoculation
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ABSTRACT: Abstract Background Worldwide, hepatitis E virus (HEV) genotype 3 is observed in pigs and transmission to humans is implied. To be able to estimate public health risks from e.g . contact with pigs or consumption of pork products, the transmission routes and dynamics of infection should be identified. Hence, the course of HEV-infection in naturally infected pigs should be studied. Results To resemble natural transmission, 24 HEV-susceptible pigs were infected either by one-to-one exposure to intravenously inoculated pigs (C1-pigs; n = 10), by one-to-one exposure to contact-infected pigs (C2-pigs: n = 7; C3-pigs: n = 5) or due to an unknown non-intravenous infection route (one C2-pig and one C3-pig). The course of HEV-infection for contact-infected pigs was characterized by: faecal HEV RNA excretion that started at day 7 (95% confidence interval: 5–10) postexposure and lasted 23 (19–28) days; viremia that started after 13 (8–17) days of faecal HEV RNA excretion and lasted 11 (8–13) days; antibody development that was detected after 13 (10–16) days of faecal HEV RNA excretion. The time until onset of faecal HEV RNA excretion and onset of viremia was significantly shorter for iv -pigs compared to contact-infected pigs, whereas the duration of faecal HEV RNA excretion was significantly longer. At 28 days postinfection HEV RNA was detected less frequently in organs of contact-infected pigs compared to iv -pigs. For contact-infected pigs, HEV RNA was detected in 20 of 39 muscle samples that were proxies for pork at retail and in 4 of 7 urine samples. Conclusion The course of infection differed between infection routes, suggesting that contact-infection could be a better model for natural transmission than iv inoculation. Urine and meat were identified as possible HEV-sources for pig-to-pig and pig-to-human HEV transmission.BMC Veterinary Research. 01/2009; -
Article: Isolation of Legionella pneumophila from pluvial floods by amoebal coculture.
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ABSTRACT: Viable Legionella pneumophila bacteria were isolated by amoebal coculture from pluvial floods after intense rainfall and from water collected at sewage treatment plants. Several isolated L. pneumophila strains belonged to sequence types that have been previously identified in patients.Applied and environmental microbiology 03/2012; 78(12):4519-21. · 3.69 Impact Factor
