Q fever in Gelderland: what is the risk to humans?

Where has Q fever been found?

bAt a dairy sheep farm in Brakel, Gelderland, with currently 83 adult animals and 45 lambs, researchers discovered Q fever contamination in the milk. This happened in the context of a national monitoring program, reports the Ministry of Agriculture, Nature and Food Quality. Q fever is a so-called zoonosis, an infectious disease that can spread from animals to humans.

Q fever is caused by Coxiella burnetii, a bacterium that can occur in many animal species and usually causes few problems. In sheep and goats, the bacterium can cause an abortion, releasing a large dose of bacteria. These can then also make people sick.

How could the animals become infected?

Companies with more than fifty sheep or goats, and companies with a ‘public function’ such as a petting zoo, are obliged to vaccinate their sheep against Q fever. At the company in Brakel there were 25 young, unvaccinated animals that were already producing milk. Experts suspect that the source of infection is in these animals.

How great is the risk to public health?

The RIVM estimates that risk to be low, partly because no abortions were observed in the animals and because some of the animals have been vaccinated. Bacteria can also be released into the environment when a healthy lamb is born from an infected ewe. The six pregnant sheep are being culled to further limit the risk. The sheep farmer may receive a fine if it turns out that some animals have not been vaccinated in time. His staff will wear personal protective equipment. Pregnant women are not allowed to come near the sheep on the farm in the near future.

“The closer to the source, the greater the risk of contamination,” says Chantal Rovers, professor of outbreaks of infectious diseases at Radboud UMC and specialized in Q fever. ‘But we know from previous outbreaks that the Q fever bacteria can also drift with the wind, infecting people miles away.’

Rovers advises general practitioners in the area to be alert to this. ‘If you have flu-like symptoms, it is wise to test for infection with Q fever. If you catch it early, you can treat it well with antibiotics.’

What can the Q fever bacteria do to people?

As far as is known, the first outbreak of Q fever in humans in the Netherlands occurred in 2007. In the years that followed, doctors found around four thousand infections, although Rovers points out that when you look at antibodies in the blood, many tens of thousands of Dutch people have become infected.

About 60 percent barely notice an infection. The rest may develop complaints such as fever, headache or pneumonia. About 2 percent of infections result in a chronic Q fever infection, a serious disease that can cause complications to heart valves and vessels, which can even lead to death.

And then there is the risk of chronic fatigue. ‘Of the group that becomes ill, about 20 percent continue to struggle with Q fever fatigue syndrome. Their complaints are very similar to those of long Covid patients. Medical science can currently do little for this group, but we hope that Q fever patients will benefit from the research currently underway into the treatment of long Covid.’