Allergies in Central Australia? You’ve Got to be Joking!
By Dr. John Weiner
Well, that was my reaction way back in 1992 when I visited Alice Springs for the first time with my family. We took along a German exchange student who was staying with us, and, together with my wife and three teenage children, we thought a trip to Alice, and a climb of Uluru (it was politically OK to climb the rock in those days) would be fun. I latched on to a small medical conference in town, and at the end of my talk on allergies, a fresh-faced American doctor came up and introduced himself. He was the doc for the US Base nearby, called the Joint Defence Facility Pine Gap, and asked if I would come up regularly from Melbourne to consult because the US personnel were “overcome with allergies” on this posting. That’s when I said “You’ve got to be joking!”
Now, I knew that coastal Australia had high levels of dust mite-related allergic airway disease. And the Southern one-third of the continent suffered from high pollen levels due to the southern pasture grasses. Early studies had confirmed high mold levels in country New South Wales. The first of many Tasmanian cohort studies, following a group of 7-year-old children from 1968, had just appeared in the medical literature. It concluded that the prevalence of asthma in Tasmania had DOUBLED in one generation, from 10.9% to 23.2% of the population. But in wide-open, semi-desert, clean central Australia – no way!
So that’s how it started. I said yes to the young doctor. It resulted in twelve years of consulting in Alice, five times a year, a week at a time, and the waiting room was always full. After three years at the Base, I moved to Alice Springs Hospital so that I could also include referrals from the local doctors. There were a wide range of allergic and immune disorders, much like a big city, but the airway allergies in that part of the world were the most mystifying. What was the cause of these allergies? Thanks to funding from the US and Australian governments, we installed a pollen trap on the base, measured pollen counts for 18 months, skin tested all attendees, obtained monthly sales of antihistamines, compared aboriginal and non-aboriginal hospital admissions with asthma, and recorded local rainfall. Conclusion? It was due to Bermuda Grass. This weed is called Couch Grass (pronounced ‘kooch’) in Australia. But it is the Bermuda Grass that you all know, botanically called Cynodon dactylon. Very high levels of pollen occurred shortly after rainfall, and correlated with antihistamine sales. Patients were invariably sensitized to Bermuda Grass. And, what’s more, they lost their symptoms when they had allergy shots for this pollen.
Just like Tucson, Arizona. Tucson? Like Alice Springs? Yep. In Tucson the annual rainfall is the same as that of Alice Springs. The big difference? In Tucson there was a law that lawns sown with Bermuda Grass had to be cut below the pollen stalks. Not so in Central Australia. Bermuda Grass, as a weed, introduced by 19th Century camel drivers, had invaded through all creek systems for hundreds of kilometers, and was taking over from the native grass.
In summary, Australia has high levels of respiratory allergy over the entire continent. The International Study of Asthma and Allergy in Childhood (ISAAC) reported that Australian children had the second-highest prevalence of asthma in the world, and the third-highest prevalence of hayfever in the world. Most of the population lives in high dust mite or high pollen areas. And, from our studies, Central Australia is not spared.
Coming to Australia? Check the seasons (we are down under and opposite, right?), bring your antihistamines, check your asthma action plan, and enjoy yourself. It’s a great place!
Dr. John Weiner is an allergist and clinical immunologist in Melbourne, Australia. His website is AllergyNet Australia www.allergynet.com.au and he is active on Twitter @AllergyNet (Note: We are so pleased to welcome Dr. Weiner to AsthmaAllergiesChildren.com that we have published his piece with the Australian spelling. Movie fans will recognize Alice Springs as the destination in “Priscilla Queen of the Desert.”)