Wetenschap - 12 februari 2015

Virus research behind submarine doors

tekst:
Albert Sikkema

The Netherlands has been facing more and more outbreaks of infectious animal diseases which can make people ill too. In the new hypermodern zoonosis lab, the CVI now has the means to track down and tackle these dangerous viruses fast.

It was ‘all hands on deck’ at the Central Veterinary Institute in Lelystad last year when a highly pathogenic strain of avian flu broke out on four poultry farms in the Netherlands. The institute, part of Wageningen UR, was working overtime to check all the specimens sent in from suspect poultry farms. There are strict safety protocols for this kind of analysis, to prevent the virus from escaping or infecting the analysts. Zoonoses, or animal diseases that can affect humans too, are increasingly common.

To be able to respond to these developments adequately, in the last few years a lot of work has gone into creating a new state-of-the-art laboratory in Lelystad. In this lab researchers can infect chickens, pigs, sheep and cattle with a zoonosis. Then they can see how the disease behaves and whether intervention is possible. The lab’s price tag: 9.5 million euros. It was officially opened this week by Sharon Dijksma, state secretary of Economic Affairs.

As you enter the new facility it most resembles an experimental livestock shed. A complex network of corridors leads to 10 livestock stalls suitable for farm animals and rodents. But a big difference compared to a normal shed lies in the safety protocols: the rooms are sealed off from each other and the outside world with hermetically sealable doors of the kind found on a submarine. Showers prevent staff – who wear protective clothing – from spreading the virus on their persons, while advanced air filter systems close off that potential escape route. One of the lab’s showpieces is the destructor, a Wallace & Gromit- like piece of apparatus which can make animal corpses virus-free. For five hours the corpses are treated with a combination of high temperatures, high pressure and acids until nothing remains of a sheep or pig but what looks like a lump of dough. ‘Even the DNA is destroyed,’ says Henk Sloetjes, head of the department of Animal Health and Biotechnology at the CVI. The price of this machine: 1 million dollars. There are 10 smaller destructors in the cellar ready to separately destroy all the manure, bedding and water from the stalls. The brain of the lab consists of 12 cupboards full of chips and software. A glimpse of how much technology it takes to be able to work safely with animal diseases such as the highly pathogenic avian flue and Q fever.


IN THE RESEARCH CENTRE

Staff coming to work at the national facility for zoonosis research enter the clean entrance hall and go to a room where they have to undress completely and put on clothes and underwear provided by the CVI. The animals to be researched come in ‘clean’ (uninfected) and are washed in a reception area, shaved and chipped so as to ensure a standardized research procedure. The animals are only exposed to the zoonosis in their stall. Then they are put into an enriched environment with distractions so they are under as little stress as possible, because stress influences animals’ immunity. There is no daylight in the animal accommodation and a rhythm of day and night is created with artificial lighting.

The staff have to move from the clean area to the stalls through four submarine doors and three chambers. They need their unique fingerprint and a code to open a door. The submarine doors, which open in turns, ensure that no air passes from one chamber to the other. Negative air pressure ensures that no air passes from the infected area to the clean area, and thorough air exchange ensures that all the air in these rooms is purified before the staff return to the clean area from the stalls.

In the heavily infected area of the stalls, the researchers wear boots, protective clothing and a mask. After being in the infected area– a stall, the operation room or the destructor – the researchers take their boots off, rinse their protective clothing with disinfectant, go to a room in which the air is replaced in a short time, hang up the protective clothing and throw out the clothes they had on under it. In the next room it is compulsory to shower for three minutes, after which they can get dried and dressed. For all these safety measures you need three square metres of sealed passageways, changing rooms and washrooms for every square metre of research accommodation.



Safety level
The new lab is very welcome, says CVI director Andre Bianchi. He explains how the safety of a lab is expressed in a Bio Safety Level with a scale of 1 to 4. Existing lab facilities at the CVI had the highest safety level for animals, v-BSL4 (v = veterinary) but for humans only h-BSL3 (h = human). ‘In the past this was perfectly adequate,’ says Bianchi. ‘Foot and mouth disease, for instance, is infectious for cows but harmless to humans. And diseases like swine fever and low-pathogenic avian flu, which came later, carried few risks.’ But this changed about 10 years ago when dangerous zoonoses started to appear in the country, including Q fever and a highly pathogenic strain of avian flu. ‘For research on these animal diseases an h-BSL3 lab was needed – one class higher that what we had available at that time,’ explains Bianchi. At modest expense, the safety levels of existing labs were raised, providing the possibility for lab research. Testing on live animals was still out of the question, however. But that is no problem now, with the new facility which is v-BSL4/h-BSL3. ‘Besides, the old procedures were very long-winded,’ adds Bianchi. ‘The new lab brings stalls, dissection room and destruction all under one safety regime.’

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More demand
 
In the new unit the CVI will be able to track down pathogens or mutants faster and better. In the coming years, the institute will be doing research on chickens, sheep and pigs which will be infected with a zoonosis in the stalls. The researchers can then establish how the infection spreads within a group, in which organs it multiplies and how infectious the virus is. The national facility is intended not only for CVI researchers but also for veterinary researchers from Utrecht University and virologists from the Erasmus Medical Centre in Rotterdam, including Rotterdam flu researcher Ron Fouchier, head of the national influenza centre.

Fouchier already has a highly secure facility for research on zoonoses such as avian flu. ‘In our facility we can do tests on chickens or ferrets in cages but not on large farm animals like pigs. So the new facility in Lelystad is a good addition for our joint research. Now we can do better research on swine fever, for instance. Research institutes such as the CVI, the RIVM and Erasmus MC collaborate well together, in Fouchier’s view. The CVI concentrates on the animal side, the RIVM on the human side and Erasmus MC on flu viruses. ‘There is a lot of overlap in our expertise but we are working better and better together to pool all the knowledge about zoonoses.’

Two thirds of infectious diseases can infect both animals and humans

In recent years, the CVI has also done research on the bluetongue virus in sheep and cows and the Schmallenberg virus in cows, sheep and goats. These are not zoonoses, admits Bianchi, but they do have close relatives which are dangerous to humans. Given that they can appear quite unexpectedly, the next outbreak could pose a public health problem. Bianchi gives the example of the outbreak of Q fever, the infection with Coxiella burnetti bacteria. Until 2007, this bacterium was rare in the Netherlands, and caused no serious problems for sheep, goats or humans. The epidemic of 2007, however, did claim human victims and left hundreds of chronically ill patients. The CVI director expects the demand for research and expertise on zoonoses to go up. The CVI is aware of newly advancing zoonoses which could get a foothold in Europe. Bianchi mentions the Rift Valley virus, the West Nile virus and the Crimean-Congo virus – all animal diseases carried by insects and a danger to both animals and humans. ‘We are experiencing more and more threats,’ says Bianchi. ‘Two thirds of infectious diseases can infect both animals and humans. This research is essential.’

Photo: Maarten Spoek


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