Browsing Articles and other publications by RIVM employees by Authors
Een uitbraak met Campylobacter fetus na het eten van rauwmelkse schapenkaas : Hoe traceer je de bron van een uitbraakKoppenaal, H; Groenendijk, F; van den Berge, M; Verkade, E; Verduin, K; Zomer, A L; Duim, B; Wagenaar, J A; Tijsma, A S L; Spierenburg, M A H; te Wierik, M J M (2017-10-17)Campylobacter fetus is a species of gram-negative bacteria whose primary reservoir is the gastrointestinal tracts of cattle and sheep. Human infections are rare, though often invasive and sometimes fatal. In this paper, we studied an outbreak of six patients with a C. fetus infection and outlined their disease histories. In each case we were able to identify factors that led to a reduced resistance, including pre-existing illnesses and old age. Because of the unusually high number of patients that presented in a time period of only five months, the Community Health Services were commissioned to identify the source of infection. Using whole genome sequencing, we showed that 5 out of 6 patients belonged to the same cluster. This One Health approach resulted in the conclusion that the infection originated from unpasteurized sheep's milk processed into unripened cheese. Finally, various measures were put into place to prevent any further outbreaks.
Weather correlates of Campylobacter prevalence in broilers at slaughter under tropical conditions in Sri Lanka.Kalupahana, R S; Mughini-Gras, L; Kottawatta, S A; Somarathne, S; Gamage, C; Wagenaar, J A (2018-04-15)Campylobacter is the primary agent of human bacterial gastroenteritis worldwide. In contrast to temperate zones, weather effects on Campylobacter prevalence in broilers under tropical conditions are under-researched. We examined the association between weather and Campylobacter prevalence in slaughtered broilers in Sri Lanka, a tropical country with weather variations led by monsoons. Each month (October 2009-July 2011), 20-30 broiler batches referring to two semi-automated slaughterhouses from five Sri Lankan provinces were tested for Campylobacter contamination and analysed in relation to temperature, humidity and rainfall. Overall prevalence was 63.8% (95% CI 59.6-67.9%, n = 542), peaking in September-November. Each 1 °C increase in monthly mean temperature up to 26 °C increased Campylobacter-positive batches by 16.4% (95% CI 0.4-35.1%). For each 10 mm increase in monthly total rainfall up to 300 mm, Campylobacter-positive batches increased significantly by 0.8% (0.1-1.5%) at 1-month lag. For each 1% increase in relative humidity up to 80% at 1- and 2-month lags, Campylobacter-positive batches increased of respectively 4.2% (1.9-6.7%) and 4.0% (1.5-6.5), and decreased by 3.6% (2.6-4.6%) and 4.0% (2.6-5.4%) for unit increases above 80%. These results suggest that even in tropical countries without marked seasons, there are weather effects possibly reflecting Campylobacter potential to colonise its preferred host and/or survive in the environment.