When Pat Mileto arrives at our Australian Centre for Disease Preparedness (ACDP), he doesn’t always know when he’ll get home again.
This is because ACDP operates a 24/7 emergency diagnostic testing service every day of the year. But Pat doesn’t run this service by himself! There are many people involved, helping ensure Australia’s livestock industries remain free from emerging and exotic diseases.
In this story, we trace the meticulous and collective efforts of our team of scientists and researchers. From the moment a report is received about a potentially sick animal, to the intricate testing processes that follow, each step is vital.
The emergency diagnostic testing service swings into action
Occasionally, farm animals show signs that raise suspicion of a notifiable disease or "Category 3" submission. This list includes avian influenza, foot-and-mouth disease or lumpy skin disease. Such "emergency animal diseases" could cause havoc for Australia’s livestock industries. It’s crucial that thorough tests are done as soon as possible. Their findings allow authorities to respond to a potential outbreak quickly and appropriately.
State or territory veterinary officers are the first to receive a report of a sick animal from a farmer or local vet. The former collect samples from the animal and submits those to their state or territory laboratory. These labs then run tests to find out what might be causing the disease.
If they suspect an emergency animal disease, they immediately notify our emergency diagnostic testing team at ACDP. We are the national reference laboratory. Our role is to run further diagnostic tests to confirm the presence or absence of a suspected emergency disease.
At ACDP, our Duty Vet team gets the first call from the state or territory vet laboratory.
Veterinary vigilance: the role of a Duty Vet
Megan Poon is a Duty Vet on our team. She is one of several trained veterinarians. They are responsible for organising the testing on the submitted samples. As a disease might strike at any time of the day or night, one member of the Duty Vet team is always on call, on rotation. When the on-call Duty Vet finds out that samples from an animal suspected of a Category 3 submission are being sent, they spring into action. They start by reviewing the information provided by the submitter.
“The aim is to get as much information as possible to provide to the lab to help make the process smooth and efficient,” Megan said.
“We’ll discuss the case with the scientists in the lab who’ll be running the diagnostic tests. Together, we provide guidance and advice on the most appropriate tests and liaise again with the submitting labs on the types of samples to submit that will be most helpful.”
After the Duty Vets deal with the incoming call, there are several teams in our microbiologically-secure labs that run tests for diagnostics. On the frontline are the Virology, Molecular and Agent Characterisation teams, who always have people on call. Depending on the submission, the Bacteriology, Histology, Serology and Specimen Accessions labs may also be called upon.
In the case of a Category 3 disease threat, the response time for testing is rapid.
Let’s meet three of the teams who provide this crucial service.
Detecting viruses with precision
Brenda van der Heide works with our Virology team. They collect the samples sent via courier from the receivals area at ACDP. They then check the paperwork to ensure they have the correct Category 3 samples that need a rapid response.
Once all is checked, the Virology team prepares the samples and then run a series of diagnostic tests. It’s their job to find a virus, any virus, in the samples – if one is indeed to be found. Luckily, the results are negative most of the time.
“The team need to confirm that a disease has been tested for and they found no evidence of it in the samples,” Brenda said.
Normally the Virology team can get these initial results within 30 minutes to 4.5 hours. They also prepare the samples for the Molecular team to run their tests.
Meanwhile, in the Molecular team...
Because the Molecular team play an important role in the initial screening for viruses, they quickly set up the required PCR assays. They can get a result in approximately three to four hours. Any positive samples are then further characterised by the Agent Characterisation team as well as cross-checked with Virology’s results.
More than 200 PCR assays are available at ACDP for detecting many different viruses. These not only detect the presence of a virus but also the amount of virus in the samples.
They have five people in their team who work on-call on a weekly rotation. One of them is Gemma Harvey, a member of the Molecular team.
“It’s been a busy two months on-call with someone either staying back late, being called in on the weekend or a combination of both, multiple times a week. Normally, we might only stay back late or get called in once every three or four weeks,” Gemma said.
“It’s a good sign though. It means livestock managers are taking the risk of disease outbreaks very seriously and alerting the relevant authorities of the need to investigate a case further.”
Informing responses with sequencing data
Pat Mileto is part of the on-call Agent Characterisation team, AKA the Sequencing Lab. They run tests to characterise the detected virus.
“This part of the diagnostics takes longer than PCR but provides much more detailed results on the disease agent,” Pat said.
“We sequence the genome of the virus to ‘characterise’ it. In other words, we compare its genetic sequence to sequences of similar virus strains. This tells us how related they are to each other. We focus on comparing regions with genetic variation. These sections of the virus can provide information on the possible origin of the incursion and sometimes the severity of the disease.”
This sequencing data helps the Duty Vet and the submitting government vets to understand which virus strain they’re dealing with. This way they can make an informed decision of how to respond or take action on the property where the samples came from.
“We can usually get the whole genome sequenced in 24 hours, sometimes less," Pat said.
“The quickest turnaround time I have seen is 12 hours.”
The results are in...
Once all the data is in, the Duty Vet reviews the final report to make sure all testing aspects are recorded. Then they make the call to the original state/territory lab with the news, whether it’s good or bad.
“It is always a relief to review the report and see the results are negative for a Category 3 submission. Fortunately, most of the time, the news is good, and everyone can relax...until the next phone call comes in,” Megan said.
“Of course, if it is a positive result, a national emergency response starts and the teams will be working around the clock, as more samples are sent in from the affected areas and require testing."
She and the entire team are extremely proud of the service they provide to Australia in a quality assured way. The vigilance and efficiency of these dedicated teams safeguard Australia's livestock industries, providing a critical line of defence against the spread of infectious diseases.