Nieuws - 7 april 2011

Spring fever

Spring is in the air. The lambs flock to the meadows again, a beautiful scene marred in the last few years by the outbreak of Q Fever. Last year, the disease even took the lives of eleven people. What lies in wait this year?

What was it about Q Fever again?
Q Fever is caused by the bacteria Coxiella burnetii, large quantities of which are released when young goats and sheep are born. This bacterium has also resulted in many abortions among goats and sheep. The disease can be spread to humans via the air. Last year, it affected 506 people, some of whom suffered severe and chronic consequences, and took the lives of eleven.

Will this happen again this year?
 Hendrik-Jan Roest of the Central Veterinary Institute of Wageningen UR does not think so. The vaccination of sheep and goats is bearing fruit. Roest is doing a study of the vaccinated goats and sheep, together with the Faculty of Veterinary Medicine in Utrecht and the Animal Health Service in Deventer. The study shows that an average of two hundred times less Q Fever bacteria are carried in these animals, as compared to animals which have not been vaccinated, report the researchers in the March issue of Emerging Infectious Diseases. This is good news, as all goats and sheep in commercial farms and children's farms have been vaccinated since mid 2010. 'It is likely that there is now much less bacteria in these locations. Too little to make large numbers of people sick as in 2008 and 2009', says Roest.

Is the threat from Q Fever gone as a result?
It's still too early to make such a conclusion. If there is a peak, it will be in the months May and July. This year, statistics from the Dutch National Institute for Public Health and the Environment show that Q Fever is present in three dairy goat farms, and general practitioners have diagnosed nineteen people with Q Fever, eight of whom fell sick. One patient died this year of a combination of chronic Q Fever and other medical problems. It is therefore advisable to be vigilant. Goat and sheep farmers should put aside their manure, are not permitted to let their animals mate with animals which have been tested positive, and are not permitted to expand. Moreover, these farms are being screened intensively for the presence of Q Fever.

Is research into Q Fever 'completed' now?
Not at all. Roest is involved in reconstructing the Q Fever epidemic which spread from 2008 from Herpen in the province of Brabant to east Brabant, south Limburg and Overijssel. He is dealing mainly with the question of how the relatively benign Q Fever bacterium, which has been making its rounds for decades in Europe, suddenly manifested itself as an aggressive pathogen in the Netherlands. The Wageningen researcher examined the different Q Fever bacteria species and found that one of them had been detected in ninety percent of the dairy goat farms in South Netherland, he reports this month in Emerging Infectious Diseases. 'This genotype had also been found in human beings in 2008', says Roest, 'but cannot be matched to bacteria strains from other countries. That which comes closest to it is the C. burnetii strain, traced to a human patient in France. This could point to a French origin for the strains found in the Netherlands.'

Does the intensive character of goat farming in the Netherlands play a role?
'That is not the cause of the epidemic', says Roest, 'but can affect the spread of the epidemic. Human beings only get Q Fever if they are exposed to too much bacteria, and this can only happen if there is a substantial number of goats in the vicinity.' He expects goats to be one of the issues in the discussion about intensive livestock farming in the Netherlands.