Opsteegh M, van Roon A, Wit B, Hagen-Lenselink R, van Duijkeren E, Dierikx C, Hengeveld P, Franz E, Bouw E, van der Meij A, van Hoek A, van der Giessen J
RIVM Report 2018-0059
Animals can carry pathogens that can cause disease in humans (zoonoses). In 2016, the RIVM and the NVWA investigated whether dairy goats and dairy sheep carry such pathogens; sometimes this is also done for livestock farmers, their family members and employees. These pathogens usually cause diarrhoea but sometimes the infections are more severe.
Research shows that a few pathogens occur often on dairy goat and dairy sheep farms. These bacteria reside in the intestines of the animals, and are excreted in manure. A small amount of manure is enough to contaminate raw milk or unpasteurised cheese. Visitors to these farms can also become infected if they come into contact with the animals or their environment. Contamination can be prevented by consuming or processing all milk pasteurized. Visitors can reduce the risk of disease by washing their hands if they have been in contact with the animals or their environment.
STEC and Campylobacter bacteria, in particular, were frequently found. STEC was detected at virtually all the farms that were investigated. Campylobacter was detected at 33 percent of the goat farms and 95.8 percent of the sheep farms. These bacteria were found much less often among the farmers and their family members. Listeria was detected less often: at 8.8 percent of the goat farms and 16.7 percent of the sheep farms, and not among people. However, it is a relevant pathogen since unpasteurised soft cheese is the most important source of Listeria infection in humans.
Salmonella was not found at dairy goat farms but was found at 12.5 percent of the dairy sheep farms. On most farms, only a type of Salmonella that is not transmitted to humans was found. ESBL-producing bacteria, which are insensitive to many antibiotics, were detected at 1.7 percent of the goat farms and 4.2 percent of the sheep farms. They were also found in 6.8 percent of the people. This percentage is not higher than for the general population.