When Mary-Anne O’Neill was a teenager, a persistent cough led to a chest X-ray revealing a dormant cyst growing inside her lung.
O’Neill, now 71, had grown up on a farm in the Snowy Mountains of NSW, surrounded by sheep, cattle and dogs, and had no idea she was carrying a parasite.
“I was 17 and I just thought it was all going to be OK because, when you’re 17, you do,” O’Neill told 7NEWS.com.au.
But the discovery led to surgery and weeks in hospital.
The cyst — measuring about 3cm and growing beneath her second rib — had formed after she swallowed microscopic eggs from a hydatid tapeworm, a parasite carried by infected dogs.
“The eggs hatch in our guts and release tiny baby tapeworms,” veterinarian Dr Liisa Ahlstrom of Elanco Animal Health on the Sunshine Coast told 7NEWS.com.au.
“These then penetrate through our gut wall, migrate through our body and usually settle in one of our organs.
“They slowly grow into these fluid-filled cysts, and these cysts can become quite large, even football-sized.”
Hydatid disease can develop silently for years. If a cyst ruptures, it can trigger a severe allergic reaction and spread further parasites through the body.
Ahlstrom said hydatid tapeworms could be difficult to detect because infected dogs may show no signs of illness.
“Hydatid tapeworms are really tiny, less than 1cm long, and dogs can have hundreds and thousands of these worms in their intestines and be completely healthy,” she said.
“They don’t make dogs sick. They make people sick.”
The parasites begin their cycle when dogs eat infected animal tissue, including raw offal. Their faeces can then contaminate soil, grass, sand and household environments with microscopic eggs.
Some eggs are sticky enough to cling to a dog’s coat, while others can survive in the environment for years.
“Even when you’re picking up dog poo and disposing of it promptly, some may get left behind and these eggs can be really long-lived in the environment,” Ahlstrom said.
Hydatid tapeworm eggs can survive for up to two years, while roundworm eggs may remain infectious for several years.
Even Australia’s harsh sunlight cannot be relied on to destroy them, with their protective shells helping them withstand drying and environmental extremes.
The risk is not limited to backyards and you don’t have to own a dog to be exposed to parasites.
At dog beaches, hookworm larvae thrive in moist sand and can penetrate human skin directly, causing intensely itchy tracks as they move beneath the surface.
“Don’t sit on a dog beach and don’t rely on a towel as well because it’s thought they can even penetrate towels,” Ahlstrom said.
“If they can penetrate skin, they can probably penetrate a towel.
“And don’t go barefoot on a dog beach. Wear shoes.”
Then just 17, O’Neill underwent surgery to remove the cyst, spending around three weeks in hospital and facing a long recovery.
Surgeons went through her rib cartilage, and her collapsed lung had to be reinflated.
She woke with drains coming out of her lung and an oxygen mask and had to sleep sitting up for weeks while her body healed.
‘It took me a long time to get used to sleeping on a flat pillow again because I associated the sitting up in a triangular pillow formation around me with safety,” she said.
Her scar stretches from her breastbone around the side of her body almost to her shoulder blade.
As a teenager, she found it embarrassing to have such a large scar from something as ordinary as petting a dog.
“I had a very vivid scar that I told people was a shark attack because that was more interesting to me than telling the whole story,” she said.
Ahlstrom said O’Neill’s experience underscored the importance of prevention, from collecting dog poo promptly and washing hands to keeping dogs up to date with worming treatment and avoiding raw offal.
“Don’t wait until you see signs of illness in your dog to know that there are worms there,” she said.
Some worms can cause diarrhoea, blood in the poo, pale gums, weakness and tiredness in dogs. Puppies with roundworms may develop a swollen belly or, in severe cases, an intestinal blockage.
Flea tapeworm segments can sometimes be seen in a dog’s poo or around its bottom, resembling “cucumber seeds” or “bits of crawling rice”.
They may also cause dogs to scoot their bottoms along the floor.
But hydatid tapeworms are different. They are too small to see and generally cause no symptoms in dogs.
“They don’t make the dog sick, and there’s no evidence of them in the poo because they’re just too small to see,” Ahlstrom said.
Health experts now recommend monthly worming treatment for dogs at risk of roundworm, hookworm and tapeworm, rather than the four-times-a-year treatment once commonly advised.
But many owners mistakenly assumed their dogs were protected against tapeworm because they used all-in-one parasite treatments, Ahlstrom said.
“Most dog owners were unaware that they weren’t protecting their dogs from tapeworms because they were using these all-in-one products,” she said.
“None of these products have included tapeworm until now.
“Advocate Ultra Chew is the first sort of all-in-one product with a single monthly dose to kill ticks, fleas, heartworm and intestinal worms, including tapeworms.”
However, she warned against combining it with a yearly flea and tick injection, but said it can be used after a heartworm injection.
Owners should consult their vet before combining treatments.
O’Neill said she had also been surprised by how little awareness there was outside farming communities
“I would say people in the country, or anywhere near sheep, would have much better knowledge than anybody in the city,” she said.
On the farm, O’Neill knew to boil offal before feeding it to dogs and wash her hands before eating.
But she had not considered that others might not take the same precautions.
“You don’t know who’s been there before or what the hygiene is or anything,” she said.
“You just assume that everyone does the preventative tablets, but you never know.”
For O’Neill, the experience changed how she viewed contact with dogs.
“It’s all invisible. You can catch it from any dog, or going on the beach when there was a dog before,” she said.
“Just because something is doesn’t mean that you shouldn’t be fearful of it.
“If the consequences of getting it are dire, then you should take whatever precautions so you don’t get it.”
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