Deadly Parasite Poses New Threat to Struggling Urban Owl Population

The first confirmed rat lungworm infections in Florida burrowing owls suggest more disease surveillance is in order.

By the editorial staff of Park Science magazine

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About this article

This article was originally published in the "Research Roundup" section of Park Science magazine, Volume 39, Number 2, Summer 2025 (August 29, 2025).

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Rat lungworm animal host locations in Florida. Burrowing owls from the current study are shown in blue (number 7).
From Jones and others, Parasites & Vectors, 2025.

Image credit: Jones and others. 2025. Living in the city: Angiostrongylus cantonensis is a novel threat to an urban population of Florida burrowing owls (Athene cunicularia floridana) in south Florida. Parasites & Vectors 18: 80.

In a world of diminishing natural habitats, many species have adapted to life in our towns and cities. Still, urban wildlife face a plethora of threats in these spaces, from cars to house cats. In the Southeast, a new threat has been growing from a parasite known as Angiostrongylus cantonensis, or the rat lungworm. Rats, slugs, and snails are key hosts for the parasite to complete its life cycle. However, other animals and people can also become infected. In these cases, the parasite cannot complete its lifecycle. Instead, the lungworm larvae migrate to the host’s brain or spinal cord, which can lead to neurological problems and even death.

Recently, researchers found the rat lungworm in a new wildlife host—state-threatened Florida burrowing owls on Marco Island. They published their findings in Parasites & Vectors in February 2025. Florida burrowing owl numbers have declined steeply in recent decades. These owls are most often found in urban areas like Marco Island. The researchers examined nine carcasses of juvenile owls that died with neurological signs and tested their brain tissue for rat lungworm infection. Testing is crucial because symptoms of infection in live animals resemble symptoms of head trauma, rodenticide poisoning, and diseases like West Nile virus. They found six confirmed and three suspected lungworm cases.

The researchers’ results highlight the otherwise invisible prevalence of rat lungworm and the health risk it poses in urban areas. They suggest wildlife professionals be aware of the rat lungworm and test suspected cases for the parasite. In urban areas with burrowing owl populations, rodent control could help minimize lungworm transmission.

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Jones and others. 2025. Living in the city: Angiostrongylus cantonensis is a novel threat to an urban population of Florida burrowing owls (Athene cunicularia floridana) in south Florida. Parasites & Vectors 18: 80.