Climate Change Drives Increase in Rat Lungworm Disease Cases in Eastern Australia

Recent research indicates that climate factors, particularly rainfall patterns influenced by climate change, are significantly contributing to the rise in rat lungworm disease in eastern Australia. This parasitic disease, caused by the worm Angiostrongylus cantonensis, has historically been confined to Southeast Asia but has now been identified in regions including Australia, North America, and Europe. The disease primarily affects rats, which are natural hosts, but can be transmitted to humans and dogs through ingestion of infected snails and slugs, which serve as intermediary hosts.

In Australia, there has been a notable increase in cases among dogs, with at least 93 confirmed incidents over a five-year period, peaking in 2022 with 32 cases. These peaks correlate strongly with periods following heavy rainfall, which creates ideal conditions for the proliferation of snails and slugs—the carriers of the infective larvae.

Veterinary scientists at the University of Sydney have developed a model illustrating how climatic conditions influence disease transmission. Their findings suggest that during wetter La Niña weather events, the likelihood of infection rises, particularly in regions around Sydney and Brisbane. The close relationship between weather patterns and disease occurrence emphasizes the importance of monitoring environmental changes to anticipate and mitigate outbreaks.

The parasite, primarily found in feral rats, spreads through contamination of the environment, where snails and slugs become infected. Humans and dogs are accidental hosts; once the larvae enter their bodies, they migrate to the brain, causing neurological symptoms and, in severe cases, death. Notably, there have been fatal cases in humans, underscoring the public health risk.

Lead author Phoebe Rivory explains that in dogs and humans, the immune response to the parasite in the brain causes the severe symptoms associated with the disease. Through a One Health approach—integrating human, animal, and environmental health—the research highlights the critical role of environmental factors in disease dynamics. Preventive strategies include avoiding contact with slugs and snails and educating pet owners about the symptoms to watch for.

Given the ongoing climate changes, especially wetter and warmer conditions, the risk of further spread and increased cases warrants urgent attention. Public health authorities and communities are encouraged to stay vigilant and implement measures to reduce exposure. Continued research is essential to understand environmental impacts better, including snail and slug population dynamics and parasite larvae availability.

This research underscores the interconnectedness of climate and infectious disease transmission, emphasizing the need to integrate climate data into disease control strategies to protect both human and animal health.

Source: [https://medicalxpress.com/news/2025-06-climate-factor-cases-rat-lungworm.html]