Since November 2016, more than 60 cases of bird flu have been reported in Denmark. DTUavisen has visited DTU Vet, where the dead birds undergo post mortem examination and analysis for contamination under strict security measures.
Arriving in reception at Bülowsvej 27, my visit is almost over before it starts, as I’m asked to sign a form stating that I will avoid contact with cloven-hoofed animals, poultry, and fur animals during the next 48 hours. However, glancing at a footnote, I see to my relief that cats and dogs are not included in the fur animal category. The so-called ‘infection notification’ is the first step towards classified laboratory status—an important part of Denmark’s emergency preparedness against avian (bird) flu.
A plastic lab coat and no fewer than three pairs of disposable shoe covers grants me access to the autopsy room where veterinarian Elisabeth Holm awaits with a dead common buzzard. The first thing I note is a horribly nauseating smell. Is it death—or blood? Elisabeth is unable to say for sure—she has long since become immune to the smell.
The common buzzard has been stored in the freezer prior to the discovery of avian flu in Denmark, so there is no risk of it having the disease, she reassures us. Had that not been the case, the autopsy would have been performed in the secure Class 3 laboratory, which we are only allowed to glance inside.
But we are here to see how the emergency response works—so Elisabeth dons her comprehensive array of safety equipment: rubber boots, a full body suit with hood, and built-in gloves over which she pulls blue disposable gloves and sleeve protectors. The impression of an astronaut preparing for a lunar mission is completed with a ‘ventilated respirator’, visored headgear, and a vacuum suction hose which directs air into the respiratory mask through a filter on the back.
A violent death
The whole scene is reminiscent of an operating theatre. Elisabeth asks for the swab and is handed a large cotton bud by the assistant lab technician. Elizabeth introduces the swab into the ‘sewer’—the technical term for the bird’s rectum—after which she quickly places the swab in a liquid-filled sample tube which the lab technician holds up in front of her.
The bird is then bathed in a disinfectant liquid.
“We use gallons of Virkon S,” says Elisabeth, as she slowly turns the bird around in the liquid and rubs its plumage. The head is carefully kept above water to ensure that no disinfectant reaches the windpipe—the area from which the next sample is to be taken. Elisabeth grabs a pair of scissors, opens the bird’s beak, and cuts the jawbone so she can gain full access to the throat and take another swab sample. She comments on the presence of a quite a lot of blood and the lab technician makes a note.
The sample material secured, Elisabeth can now begin the actual autopsy of the wounded buzzard lying in the metal tray—its eyes glazed white. The eye colour has nothing to do with disease, but rather the trip in the freezer, she explains.
“The bird is bloody, has been exposed to external violence, and has a broken wing,” reports Elisabeth, wiggling its wing slightly. When she opens the bird up fully, she can see that it died from a single shot. But hang on a minute— aren’t birds of prey protected? Yes, but in Karup Airport—where the buzzard was found—you are allowed to shoot them for reasons of safety.
Died while eating
As expected, there are no signs of avian flu. The disease typically causes severe bleeding in the pericardium and other organs, but here, the blood is clearly from the shot. The bird is also in good condition,” Elisabeth observes. Following further examination of the oesophagus, she discovers it was actually shot in the process of eating a frog. Birds with bird flu can easily be in good condition, as they die very quickly after contracting the virus and thus avoid becoming sickly and ‘withering away’ as she puts it.
The autopsy is over. The lab technician just needs to complete the last section of the form.
“It’s a female,” says Elisabeth, who has already gone further with the autopsy than she would normally do. She is only required to take the samples and make a simple assessment of the bird’s condition. Typically, there would be a whole queue of birds waiting to be examined. Then it would be a case of quickly but calmly wrapping the bird thoroughly in plastic to avoid potential contamination, removing the protective over gloves and sleeves, and placing everything in a bucket to be sealed and sent for incineration.
Everything in the laboratory is disinfected with Virkon S—instruments are deposited in the autoclave while Elisabeth dons a new set of gloves and protective sleeves. Now she is ready to receive the next dead candidate.
Around the labs
Meanwhile, the sample tube begins its long journey around the building’s laboratories, after being sprayed with Virkon S and wrapped in several disinfected plastic bags. The first port of call is yet another class 3 laboratory with access control, where protective clothing, wooden clogs, safety goggles, and mask are all mandatory. Here, the samples are exposed to a second fluid, which inactivates the virus so it is no longer infectious.
A robot then centrifuges, so to speak, the hereditary material out of the sample. The pure RNA is mixed with various reagents, and finally, the mixture is placed in the PCR machine, which analyses and delivers the final result: negative or positive—which is clearly visible on the computer screen.
The results are reported to the Danish Veterinary and Food Administration, which then assesses the situation and, for example, decides whether the country’s chickens and other breeding birds are to remain in isolation.
Forty-eight hours—that is how long DTU Vet has to examine each bird that is brought to Bülowsvej by specially trained staff from the Danish Emergency Management Agency. At best, the whole process takes no longer than 24 hours—but unforeseen complications with equipment and analyses can cause delays.
Elisabeth has rid herself of her space suit. On this particular morning, no birds requiring urgent examination were submitted. A little naively, I ask Elisabeth what it is like being surrounded by so much death and dangerous diseases.
She responds with an enthusiastic smile:
“I find it tremendously exciting, but many people would probably find it disagreeable—one thing’s for sure—you have to be able to deal with the sight of maggots.”