Current diphtheria outbreak in northern Australia

Hello everyone and welcome to another Good GP podcast. My name is Dr. Rami Rahman, I'm a specialist journal practitioner and a practice owner based in Perth. And today I'm really excited that we are joined by Dr. Paul Leffler, who is a public health physician based in Western Australia. I would like to begin by acknowledging the traditional custodians of the land on where we are meeting today. And today, Paul and I are on Wajuknung A people land and pay my respects to elders past and present.

I would also like to extend our respect to any Aboriginal or Torres Strait Islander colleagues who are also joining in and listening in the podcast today. So Paul, thank you so much for joining here today. We are discussing an important public health issue that many Australians may not have actually thought about for many years.

Diphtheria This is following the significant outbreak affecting parts of northern Australia, particularly in Northern Territory and regions of Western Australia, and we are seeing some hot spots in other parts as well. So without further ado, let's dive straight into this to help unpack what it means for our GPs, our communities and the families around Australia. So, for many people, diphtheria sounds like a disease from the past. What exactly is diphtheria pool and why can it be so dangerous?

Thanks, Rami. Yeah, thanks for having me. Diphtheria is a bacteria, as you know, and it's dangerous because it produces a toxin that is really effective at killing cells. So that's what the diphtheria bug does. I've been educated by David Spears at our laboratory here that when the bacteria needs iron, it produces this toxin and it just stops protein synthesis and kills the cell.

Well, what does that mean on a macro level, on a clinical level? What has been known and feared for in the past is causing really severe throat infections. And you can get this buildup of dead tissue called a pseudomembrane, a grayish membrane, that can become so prominent it can block the airways. And that's why diphtheria was feared and fatal. It can also produce a lot of swelling in the neck that linked that enough that the a thing called bull neck.

because things get so bad. And that's what we think about when we think about diphtheria historically. But it also has skin manifestations, cutaneous infections, that are essentially wounds that don't heal. And they can also have this sloughing gray material on them as well. But essentially they can look like other skin lesions as well, but then transmit to other people's throats potentially.

Yes, thank you for that, Paul. So what are the early warning signs that our clinicians and GPs should be looking out for, particularly with both respiratory and skin forms being seen with this outbreak?

So I think it's important to put some context here about the outbreak we're experiencing in Australia. I mean, I would call it unprecedented because we haven't really seen diphtheria outbreak. in resource rich countries with highly vaccinated populations. So here in WA as of Friday, we've had eighty seven cases. Almost all of those are in a Kimberley and ninety six percent of those are in Aboriginal individuals.

And I know over in the Northern Territory where they've had more than a hundred and thirty cases, their epidemiology is pretty much the same. And the new Australian CDC is saying that most of these people live in outer regional, remote or very remote areas. So that's who's being affected by this outbreak thus far. So why it's important for clinicians everywhere to be cognizant that this is occurring, the risk is really in these remote Aboriginal communities at the current time.

So what to look out for, obviously severe sore throat. And if you look in the back of the mouth and they have a pseudo membrane, that would make one think, hey, I should think about diphtheria. Also skin infections that don't heal. would make you think that maybe I need to culture this and see it it's diphtheria. But I wanna say that at this point in time, some epidemiological risk that make you lean towards that diagnosis, such as being Aboriginal and being from one of the areas where

Yeah, certainly, Paul. I think for the interest from a general practice point of view, can you just walk us through what the symptoms that a patient may present with and when should that suspicion come up for a GP? You know, unfortunately the early stages are gonna look like many other illnesses that uh GPs face, but it's a severe sore throat that's getting worse, fever and toxicity, honestly. And then for skin infections it's

skin infections that don't heal that are severe and that sometimes they're described as punched-out lesions because they can just become quite necrotic with a uh relatively clean border on them. But often these skin infections have multiple pathogens in them when they're cultured. Okay. So then just taking it back to the clinical consulting room from a GP's perspective, can you tell us a little bit about and remind us about the investigations of the swabs that we would need to consider?

So you want to go for a culture, right? Because typically in most laboratories you first need to grow it the bacteria up and then they need to test whether it has the toxin gene. So there will be people that have diphtheria isolated from their throats and from their skin wounds.

but that particular strain won't have the gene capable of making toxin. So those we don't worry about so much because they're less of a threat. So you want to do a culture and then here in our laboratory, they are also collecting PCR swabs because they have an experimental PCR that they're rolling out that can make the turnaround time faster. So those two swaps is what you'd order. And if you suspect Ethereum, you definitely want to write it on a request form.

Absolutely. And I think it's probably prudent to get some advice from the public health unit as well, the local public health unit. So when should someone seek some urgent medical attention?

obviously if they're have a severe sore throat and or a skin lesion it's not healing. But again, for diphtheria, we're really talking about the fairly height epidemiological group right now, which is Aboriginal individuals in the Kimberley, primarily, some in the Pilbara, and we have had a couple cases in the Goldfield, so it may be spreading, but it's really those folks that have been at risk for diphtheria so far.

Yep, thank you. So vaccination has historically kept diphtheria under very good control in Australia. Can you walk us through when diphtheria vaccines are routinely given and who should be thinking about boosters right now? Yeah, fantastic question. So as you know, we do a lot of vaccination against diphtheria because it was so feared and so deadly in the past. So as a infant, you're getting your first jabs at six week and two months and then four months and six months.

Then there's another vaccination at 18 months, then four years of age with a diphtheria containing vaccine. And then we have a school program which does the year seven program. So really quite a few doses by the time you've graduated from high school if you've had all of those. And then historically we recommended a booster dose of tetanus end diphtheria containing vaccine if it'd been more than ten years since your last dose. And that has stood until recently.

where in these outbreak areas in the Kimberly and the Hilbert and the Goldfields where we've cut that down to five years. If you haven't had a dose in five years, we're recommending a booster for people that have live up there or have contact. has significant contact with Aboriginal communities. But I think we really need to talk about the vaccination approach because the vaccine is very effective at preventing severe disease.

But it's not going to be sufficient to stop transmission. And this is why the vaccine for diphtheria is is a toxoid vaccine, meaning it's producing antibodies against the toxin. It tricks your body into thinking it's seeing the toxin and that's what it goes after. So it doesn't actually have any effect unless the bacteria is making the toxin.

So it's not going to affect the bacteria's growth or transmission very much. So we shouldn't be relying on vaccination to think that it's going to stop this outbreak. What it's going to do, and I think what we're seeing, it's it's really shifted the clinical spectrum to be more mild.

So of our eighty-seven cases, only one of those has been serious that needed to be metavac down and received diphtheria antitoxin, which is antibodies that have been derived from horses concentrated, and we give that for somebody severely sick. But there's only one of those cases. And then we've had thirty episodes of respiratory pharyngeal diphtheria, but they've been mild. And then we have the skin infection.

So I think we are seeing this outbreak of diphtheria in a highly vaccinated population moving this severity to much more milder illness. But if you have enough of those illnesses, you're eventually, you know, on the clinical curve of severity, you're eventually gonna end up with some more very serious and potentially life-threatening infections occurring.

Yeah, certainly. And really good point to raise in relation to that. So I guess that takes us on to the next question, which is why are we seeing this outbreak now, particularly across northern Western Australia and in Northern Territory? And is it largely about the declining vaccination rates, the booster gaps, or are there other public health and social factors contributing to this?

Yeah, very good question. We've thought a lot about this and essentially because we want to figure out how we can stop it. And to have an outbreak that's thus far limited to Aboriginal individuals mostly, as I mentioned, ninety five percent of the cases. in living in remote areas and the large proportion of skin infections we're seeing in this outbreak leads one to believe that it's skin infections that are driving this.

But essentially the high rates of skin infections historically and currently in the individuals is where the diphtheria is getting in. And then once it gets established, it's spreading to other people in high density housing. So I really think if we want to get in front of this, we have to address the factors that are allowing high rates of skin infection. And you know, there has been a recently an Aboriginal Environmental Model of Care developed.

to look at this because it's not skin infections are not just important for diphtheria, but they're also important for many other things like rheumatic heart disease. So it seems like we need to get our heads around how can we improve things environmentally for these communities where we can stop these skin infections and ultimately hopefully stop this diphtheria operator.

Yeah, thank you, Paul. So what is the key public health message that you would like to send out today both to our communities and our GPs and particularly those in regional and remote Australia to hear right now about protecting themselves and limiting further spread?

Yeah. So I think for the practitioners in the areas that are being affected, regional and remote areas, it's to make sure your patients are fully vaccinated and recently vaccinated, because we know we can protect individuals from serious illness, severe illness through vaccination. But to others outside, I think it's important to say we don't want to suck up all the vaccine here in Metro with worried well or people that are concerned.

about something that's unlikely to affect them. We need to make sure we're getting that vaccine to the areas that are really having the issues right now. And that's important that we stay focused on that. And then for other decision makers, I would say Let's own up to the fact that we need to get in front of these environmental conditions that foster skin infections.

And if we want to get in front of diphtheria, that's gonna be a longer haul. It's gonna take a quite a bit of resources, but it's something we need to do not only for diphtheria, but for skin health and all the ramifications that flow on from that. Yeah, great. Thanks, Paul. I think it's been very helpful to have a bit of insight into the understandings of why and what to do now and things to look out for within our GP consults as well. So

Thank you so much, as always. It's been really lovely having a chat with you. I just want to also make a note for our listeners that this information is current as of this recording, which is on the 25th of May 2026. as of midday Australian Western Standard Time. So on that note, Paul, thank you as always and look forward to having a chat about something else next time. Thank you, Ramya. Really appreciate it. Make sure you subscribe.

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