The European Union summary report on trends and sources of zoonoses, zoonotic agents and food‐borne outbreaks in 2014

In 2005, Q fever was diagnosed on two dairy goat farms and 2 years later it emerged in the human population in the south of the Netherlands. From 2007 to 2010, more than 4,000 human cases were notified with an annual seasonal peak. The outbreaks in humans were mainly restricted to the south of the country in an area with intensive dairy goat farming. In the most affected areas, up to 15% of the population may have been infected. The epidemic resulted in a serious burden of disease, with a hospitalisation rate of 20% of notified cases and is expected to result in more cases of chronic Q fever among risk groups in the coming years. The most important risk factor for human Q fever is living close (<5 km) to an infected dairy goat farm. Occupational exposure plays a much smaller role. In 2009 several veterinary control measures were implemented including mandatory vaccination of dairy goats and dairy sheep, improved hygiene measures, and culling of pregnant animals on infected farms. The introduction of these drastic veterinary measures has probably ended the Q fever outbreak, for which the Netherlands was ill-prepared.

We collected 886 samples (68 feed ingredient samples, 189 dust samples, and 629 feed samples) from 3 feed mills each of which produced between 100,000 and 400,000 tons of feed a year. Samples were collected on 3 d (Monday, Wednesday, and Friday), during 2 seasons (early spring and summer), and between 0700 and 1700 h approximately once per hour. Samples were collected from 5 locations within each mill: ingredient receiving, at the mixer, at the pellet mill, from pellet coolers, and at load-out. Temperatures were taken of the samples obtained at the pellet mill immediately following collection. All samples were analyzed for Enterobacteriaceae counts (EC) and Salmonella. The data confirm that feed ingredients and dust can be a major source of Salmonella contamination in feed mills. There were no differences (P < 0.05) in the Salmonella contamination rates of samples collected in spring as compared with samples collected in summer. Salmonella contamination rates were observed to be higher in samples collected on Friday compared with samples collected on Monday or Wednesday, an effect that may be management related. Data collected at the pellet mill clearly illustrate the uneven distribution of Salmonella contamination in feed as well as the need for control of dust around the pellet mill. Feed samples (both mash and pellets) contaminated with Salmonella contained significantly higher EC than samples not contaminated with Salmonella. Thus, EC may provide some indication of the likelihood of Salmonella contamination in feed samples.

A Bayesian modelling approach comparing the occurrence of Salmonella serovars in animals and humans was used to attribute salmonellosis cases to broilers, turkeys, pigs, laying hens, travel and outbreaks in 24 European Union countries. Salmonella data for animals and humans, covering the period from 2007 to 2009, were mainly obtained from studies and reports published by the European Food Safety Authority. Availability of food sources for consumption was derived from trade and production data from the European Statistical Office. Results showed layers as the most important reservoir of human salmonellosis in Europe, with 42·4% (7 903 000 cases, 95% credibility interval 4 181 000-14 510 000) of cases, 95·9% of which was caused by S. Enteritidis. In Finland and Sweden, most cases were travel-related, while in most other countries the main sources were related to the laying hen or pig reservoir, highlighting differences in the epidemiology of Salmonella, surveillance focus and eating habits across the European Union.