Latest news with #ratlungworm
The Guardian
18 hours ago
- Health
- The Guardian
What is rat lungworm disease and why are cases rising in dogs in Australia?
Cases of rat lungworm disease have been increasing in dogs on Australia's east coast over the past five years, according to new research from the University of Sydney. A very rare but sometimes deadly condition caused by worm larvae travelling up the food chain, the disease has been found in a small but increasing number of dogs in areas affected by heavy rain, and occasionally also in humans. So why are cases growing and how worried should we be? The rat lungworm, or Angiostrongylus cantonensis, is a parasite that originated in south-east Asia but has spread to other parts of the world, including North America, Europe and Australia. The parasite's natural host is feral rats, but it can accidentally make its way to other animals through a complicated transmission process involving snails and slugs as intermediate hosts. When it finds its way into humans and dogs, rat lungworm can cause a disease called neural angiostrongyliasis. In humans, it's diagnosed as a kind of meningitis, or eosinophilic meningoencephalitis. Symptoms in humans include headaches, a stiff neck, tingling or pain in the skin, fever, nausea and vomiting. Symptoms in dogs include hindlimb and tail paralysis, urinary incontinence and abnormal pain responses. The time between eating the infected slug or snail and getting sick is usually between one and three weeks. University of Sydney doctoral researcher Phoebe Rivory, lead author of the recent paper, explained that it's not the parasite itself that does the damage but the body's attempts to fight it. 'In dogs and humans, the parasite enters the brain but rather than progressing to the lungs like it does in rats, it is killed in the brain by our own immune response. It is that overt immune response that causes severe headaches and sensations,' Rivory said. New South Wales Health says it is rare for humans to develop meningitis in response to rat lungworm, and most people who contract rat lungworm have no symptoms at all, while others may have only mild, short-lived symptoms. Rats infected with adult worms excrete larvae in their faeces, which is then ingested by snails and slugs. Dogs and people are most likely to contract the parasite when they deliberately or accidentally eat a raw snail or slug carrying the larvae, or unwashed vegetables, such as lettuce, contaminated with infected slime. The parasite is not contagious from person to person. In a well-known case, Australian man Sam Ballard contracted eosinophilic meningoencephalitis in 2010 after being dared by his friends to eat a slug. He fell into a coma for 420 days, and acquired a brain injury. Ballard died in 2018, aged 29. In another well-known case, an American woman was found to have rat lungworm disease after multiple attempts to seek medical help for strange symptoms after a holiday to Thailand, Japan and Hawaii. The University of Sydney researchers have been examining the prevalence of rat lungworm disease in dogs on the basis that they are a sentinel population for humans – that is, increased rates of the disease in dogs can be an early warning sign of human disease risk. Researchers analysed 180 clinical samples taken between 2020 and 2024 from dogs suspected to have had the disease, and confirmed 93 cases, all in or around Sydney and Brisbane, and a 'gradual upward trend'. They also discovered a spike of 32 cases in 2022, correlating with high levels of rainfall, which tends to supercharge snail and slug proliferation. Confirmed cases of the disease in dogs are still very low, restricted to NSW and Queensland, and have fallen since the 2022 spike identified by the researchers, although not to 2019 levels. The researchers suggest that educating communities about how to avoid infection, and what symptoms dog owners should look out for in their pets, may be worthwhile. Rat lungworm is not a notifiable disease in NSW due to its rarity. In both NSW and Queensland, preventative anti-parasitic treatments for people, especially children, known to have ingested slugs or snails can be accessed through the health system.
Daily Mail
18 hours ago
- Health
- Daily Mail
Aussie dog owners on high alert for dangerous parasite spread by slugs
Aussie dog owners should remain on high alert for a dangerous parasitic disease that cause a lethal brain infection in both dogs and humans. Rat lungworm disease is a rare but life-altering infection caused by larvae of the parasitic worms found in feral rats and spread by snails and slugs. University of Sydney veterinary researchers are reporting a rise in cases in Sydney and Brisbane following heavier-than-usual rainfall. Up to 93 cases of rat lungworm have been recorded in the five years to 2024 with the risk of infection highest between two and 10 months after heavy rain. Dogs can become paralysed or die if they eat an infected snail or slug. Two Australians have died from the disease to date, including Sydney rugby player Sam Ballard who died after eating an infected slug as a dare in 2010. Mr Ballard suffered a severe brain infection and fell into a coma for 420 days. He died in 2018, at the age of 28, following an eight-year battle with the disease. 'These snails and slugs, and the infective worm larvae in them, can accidentally be a disease source to us humans and our pet dogs,' researcher Jan Šlapeta said. 'Once in humans or dogs, the worms quickly get to the brain where they cause disease.' People are only at risk if they eat an infected snail or slug, like Mr Ballard did, or consume the slime left behind on lettuce and other raw produce. Most people infected with the disease can recover without treatment over days, weeks and months but for some it can be catastrophic. The disease can cause severe meningitis and in rare instances be fatal. NSW Health has advised Australians wash fresh produce before eating and to wash their hands after gardening or handling snails or slugs. There have been 28 human cases between 1971 and 2018, and most people were infected from eating unwashed lettuce or vegetables. The mortality rate was 18 per cent, 14 per cent suffered long-term neurological issues and 57 per cent made a full recovery.
Yahoo
a day ago
- Health
- Yahoo
Brain worm spike detected in Australia following extreme weather event
A tiny parasite that can infect human brains has the potential to change our way of life in Australia, threatening not only our health but what we eat. Originally from Southeast Asia, rat lungworm is now established along our east coast, with infections found as far south as Jervis Bay. University of Sydney research has linked spikes in infections of the worm in animals to heavy rainfall, because the worm is commonly found in slugs and snails that proliferate during wet weather. A study of 93 dog infections in Sydney and Brisbane found 32 occurred directly after a single rain event, which were likely triggered after pets came into contact with common garden molluscs. The researchers found risk was elevated for between two and 10 months after heavy rain. The study's senior author, Jan Šlapeta from the Sydney School of Veterinary Science, told Yahoo News it's unclear how far south the parasite will spread. But with the world's weather becoming warmer and wetter, it's possible it could one day make its way down to Melbourne. "It has the potential to spread further. An indicator is that 20 or 30 years ago, we did not talk about it in America or Europe. Now it's in the southern states of the United States, it's creeping into Europe, it's in Spain," he said. "I think climate change is very much helping this parasite spread further." Interactions with slugs and snails are the most common way for people to become infected, either by accidentally or intentionally eating them, or by consuming unwashed salad they've had contact with. In 2010, a Sydney man died after he ate a slug following a dare. It's unusual for anyone in Australia to eat an infected snail because of their large size, but that could change if there's a similar biosecurity breach to what has occurred in Hawaii. It's on the Big Island that a tiny semi-slug,Parmarion martensi, has invaded the landscape. It's so small that it's easy to accidentally consume when eating salad greens and fresh fruit and vegetables. "You can't wash them off or see them. The number of human cases [of rat lungworm] have increased dramatically," Šlapeta said. "In Australia we do not have this semi-slug. Is there a potential? We can't yet tell. But we have areas up north that are similar to Hawaii. I don't want to be an alarmist, but this parasite could create more havoc. "If this semi-slug comes in, then it might end up on the veggies that people have got in their backyards. And that would change the landscape of this disease completely, like it changed in Hawaii." The semi-slug would complete a cocktail of invasive species that Šlapeta doesn't want to see become established in Australia. "The parasite is invasive, the rat is invasive, the European slugs that we see in the backyards of Sydney are invasive, but if we bring in the semi-slug... it could change the way we grow greens and behave in restaurants," he said. The first sign the worm has reached a city is usually that animals in its zoo have become sick, with curious primates often picking up slugs inside their cage and then becoming sick. Reports made by wildlife rescue volunteers are also useful in monitoring its spread, as tawny frogmouths and possums often get sick in large numbers. Since rat lungworm, also known as Angiostrongylus cantonensis, was first detected in Brisbane in the 1970s, at least six people have been infected, two of whom have died. When it comes to infections in people, most are asymptomatic, and many cases likely aren't diagnosed. Seven dire reasons it might be time to leave Australia – from floods to fungus Travellers could trigger mosquito disease outbreak in Australia as weather warms Details in satellite photos spark 'worrying' prediction about colony of thousands During its first phase of life, rat lungworm larvae hatch in the lungs of rats and is then passed through the animal as faeces. Slugs and snails consume that faeces and the worms grow inside of them. Rats then eat the slugs and snails and the process begins again. The process is relatively harmless to slugs, snails and rats, but in other hosts like humans, dogs or native birds and mammals, the body can overreact and try to kill the parasite. On rare occasions, it causes an infestation in the brain that triggers an immune response that causes inflammation. Symptoms normally set on between one and three weeks after a slug or snail is eaten, and include headaches, nausea, vomiting, a stiff neck, pain in the skin and fever. The University of Sydney study on rat lungworm infections in dogs advocates for a One Health approach to combating the parasite. This concept means recognising that animals and humans live in the same environment and are therefore interconnected. But how best to respond to the problems it's causing is something that's left Šlapeta stumped. "That's the million dollar question. The parasite is moving wherever it wants," he said. "We can't eliminate rats, we can't eliminate slugs, so we just have to be more vigilant around the clinical signs in our pets and ourselves. "But there's not much we can do about tawny frogmouths. They will keep looking for some sort of food, and if the slug or snail is infected then they will become infected too." The lead author of the study into rat lungworm in dogs was Sydney University's Phoebe Rivory. The research was published in the Journal of Infectious Diseases. 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ABC News
2 days ago
- Health
- ABC News
Researchers uncover spike in 'rat lungworm disease'
Pet owners are being urged to be on alert after a spike in a potentially fatal disease affecting dogs on Australia's east coast. Scientists say they have confirmed 93 cases of 'rat lungworm disease' between 2020 and 2024, with most of these in Sydney and Brisbane. The study found dogs usually fall ill after eating potentially infected slugs and snails.
