July 1, 2025, 1:42 pm | Read time: 5 minutes
He grows in snails, thrives in rainy conditions, and can infect the brains of humans and animals: The rat lungworm is spreading worldwide–along with the fear of an underestimated infection risk. Studies from Europe and Australia reveal alarming trends. How significant is the risk for dogs in Germany?
A small parasite hiding in gardens and thriving in rainy conditions is causing significant concern: the rat lungworm (Angiostrongylus cantonensis) infects rats but is also transmitted by so-called “killer snails.” This species is spreading globally at an increasing rate, leading to a growing number of severe infections in dogs–potentially fatal or causing lasting neurological damage. Here, you’ll learn what is known about it and how likely the dangerous creature is to spread in Germany.
Rat Lungworm Already in Europe
Angiostrongylus cantonensis is among the lungworms. Various species of these parasites are known in Germany and can be transmitted primarily through snails. Depending on the type of lungworm, cats and dogs can be affected (PETBOOK reported).
However, the rat lungworm is considered a particularly dangerous species–and a beneficiary of climate change. Originally described as a single species in China in 1935 (hence the species name cantonensis), this specific worm has spread from Asia to many parts of the world.
It causes the greatest concern in Australia, where infections with the parasite have been known for 50 years but are now increasingly seen in dogs. The rat lungworm is already native to parts of Europe as well. A look at the studies shows how concerned veterinarians and biologists are.
Australia Identifies 93 Cases in Dogs
A study by the University of Sydney documented 93 cases in dogs between 2020 and 2024. However, lead researcher Phoebe Rivory warns: This number is likely just “the tip of the iceberg,” as many cases go undetected. The doctoral candidate in the Veterinary Parasitology research group at the University of Sydney has conducted extensive research on this topic in recent years.
In her latest investigation, Rivory and her team demonstrated that certain factors favor the spread of lungworms. The researchers report an increase in cases since 2010, with dogs proving to be “sentinel species”–a sensitive early warning indicator.
Factors Favoring the Spread of Rat Lungworms
The disease caused by the rat lungworm, also known as neural angiostrongyliasis, affects the central nervous system of so-called accidental host species like dogs and humans. The parasite is transmitted through the consumption of infected snails, food contaminated by infected rats, or contaminated water.
The worm’s larvae migrate to the brain as the infection progresses, causing severe inflammation that often leads to paralysis and even death in dogs. According to researchers, the rise in infections is closely linked to climate change and increasing urbanization.
In recent years, particularly rainy weather has favored the proliferation of snails and slugs, especially on Australia’s east coast–peaking in 2022 when 32 dogs were infected. 1
Also Found in Spain
However, sightings are not limited to cases from “Down Under.” Various species have already been infected in Spain, and intensive research on the rat lungworm is being conducted at the Cardenal Herrera-CEU University in Valencia. In recent decades, occurrences have also been documented on European islands–such as the Canary Islands and Mallorca.
European researchers primarily see increasing globalization, international trade, and climate change as reasons for the growing number of cases in Spain and the spread of the parasite in temperate climates. The findings in Valencia could thus mark not only a scientific sensation but also the beginning of a new phase in the spread of the disease.
In a 2023 study, researchers showed that nine percent of rats in Valencia already carry the virus. It didn’t matter whether it was the brown rat (Rattus norvegicus) or the black rat (Rattus rattus). This was true for animals from both urban and rural areas, indicating a widespread presence in the region. The detection in two different rat species suggests possible adaptation and long-term establishment of the parasite in the ecosystem. 2
Lungworm Can Infect Various Species
How serious the problem in Spain could become is shown by further investigations from the research group in Valencia. In April 2025, a study was published documenting cases in many different animals, including house mice, hedgehogs, various lizards, and even primates.
Three lemurs–a red-fronted lemur (Eulemur rufus) and ring-tailed lemur (Lemur catta)–fell ill at Bioparc Valencia. The animals exhibited neurological symptoms such as paralysis and coordination disorders. Two animals died, and one was euthanized. A pathological examination confirmed that all three were infected with the rat lungworm. 3
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Recognizing and Treating Lungworm Infestation in Cats
New Cases of Rabbit Plague in Germany! Pets Also at Risk
How to Protect Yourself and Your Dog
Neural angiostrongyliasis can also cause severe neurological symptoms in humans, such as eosinophilic meningitis, paralysis, or even death. Between 1971 and 2018, 28 cases were documented in Australia. The most well-known case is that of Sam Ballard, a young rugby player from Sydney. In 2010, he took a dare and ate a garden snail. He became infected, fell into a 420-day coma, and suffered severe brain damage for eight years before dying in 2018 at the age of 28.
Currently, no cases of rat lungworm infection are known in Germany, but the Tropical Institute issued a warning in 2023 following initial investigations from Valencia. So, if you’re traveling to Spain with your dog, you should keep a few things in mind:
- Do not consume raw or partially cooked snails
- Always prevent dogs from eating snails or wet grass after rain
- Wash fruits and vegetables thoroughly
- Watch for early symptoms and go directly to a (veterinary) doctor
While infection with a rat lungworm is potentially fatal, there are several treatment options if detected early.
But caution should also be exercised in your own garden and when walking your dog. As mentioned earlier, there are other lungworms that can infect dogs even here. You can protect yourself using the same methods mentioned above and additionally ensure you always wear gloves when gardening. Prevention is crucial, as once the parasite reaches the brain, the chances of recovery are drastically reduced.