“It’s come to the stage now that if you come from Beacon Hill or north, particularly if you come from the peninsula, and you have an anaphylaxis and you don’t understand why that occurred necessarily … then my first question of you will be ‘what happens when you’re bitten by a tick?’”

But not everyone who gets bitten by a tick develops mammalian meat allergy. So what’s going on?

Ticks are notorious for their ability to trigger life-threatening allergic reactions to proteins found in their saliva. Australia has a particularly high concentration of individuals with serious allergies to tick bite itself, which may be partly due to the especially elongated mouthparts of Ixodes holocyclus. But this meat allergy was something different.

At first, van Nunen wondered whether there might be something in the tick’s saliva from its previous host; perhaps a bit of protein from an animal like a bandicoot that the human immune system associates with the immunoreactive tick protein, and therefore reacts to equally.

In the end, the answer came from the other side of the world.

A group of US doctors had also been seeing an unexplained surge in severe allergic reactions to a drug used to treat colorectal cancer. As they reported in 2007, nearly one in four patients in Tennessee and North Carolina treated with cancer drug Cetuximab developed a severe reaction, compared to less than one in 100 elsewhere in the country.