The July 26 Eurosurveillance contains a report about a human brucellosis case stemming from the consumption of a soft raw milk cheese that traced back to a dairy and individual cows. Human brucellosis in France is mandatorily notifiable.
France has been officially free of bovine brucellosis since 2005, and its officials took swift and comprehensive action when tracing back this case.
After the human case, four months later a bovine case of brucellosis was found on 21-cow dairy farm after a cow aborted. In France, abortion in ruminants is mandatorily notifiable and the investigation of abortion includes examination for brucellosis. In this case, as per French regulations, the herd was slaughtered and tested. The index animal was found to be positive for Brucella melitensis biovar 3. Brucella was isolated from a second animal in the herd, and PCR-positive results were obtained for four further animals.
After further investigation, it was found that the affected person had visited the farm and purchased/consumed the cheese several months prior to exhibiting clinical signs.
An example of “One Health”
This case demonstrates a “One Health” mindset in France. Not only did regional health authorities work with the veterinary community, but retailers were notified and the cheese was recalled, and physicians in certain districts were informed so they could educate consumers to watch for clinical signs of brucellosis infection. Authorities also stopped any movements of animals from other herds that had epidemiological links with the infected herd until the investigation was over. This was a great example of a multitude of agencies working together to quickly assess and investigate the case, as well as prevent any further spread of disease.
It’s not known how the herd, which had not received any imported animals, became infected, but there are a few hypotheses. It’s being investigated whether animals had been introduced in one of the herds that sold animals to the affected farm or whether the affected herd had been in contact with animals of neighboring farms. Another hypothesis would be a contamination of cattle by wildlife; B. melitensis biovar 3 is the most common biovar isolated in ruminants worldwide, and therefore the identification of this biovar in a district like the French Alps with many different ruminant species cannot contribute to a more precise hypothesis. The veterinary investigations are still ongoing.
Raw milk a danger
From 2002 to 2011, 219 human cases of brucellosis were confirmed in France, and 84% of them were patients infected through the consumption of raw milk products or direct contact with animals in (or from) countries with enzootic brucellosis. This once again points to the risks of drinking raw milk or consuming products made from raw milk.
Read more about human brucellosis from the Centers for Disease Control and Prevention here.
Read more about the risks of consuming raw milk here.