\u201cOur findings indicate [locally acquired] infections, which pose a substantial risk to humans and accidental vertebrate hosts,\u201d they wrote.<\/p>\n
Accidental brain hosts <\/p>\n
Like many parasites, the rat lungworm has a complicated life cycle<\/a>.<\/p>\n Adult worms mature, mate, and lay eggs in a rodent\u2019s lungs. These eggs hatch into larvae and are coughed out into the rodent\u2019s throat, then swallowed back in through the digestive tract, finally ending up in poop. A snail or slug then eats the contaminated poop (or gets infected through close contact). Once inside the snail, the larvae enter their infectious stage of life, ready to be eaten by another rat and start the cycle anew.<\/p>\n<\/p>\n Sometimes, though, the larvae infect other hosts. In some animals, the worms can bide their time until they\u2019re eaten by rats, but in humans, they reach a dead end. The larvae still try to carry out their life cycle in people, though, which includes migrating to the brain. Though some infected with these brain worms never become sick, others can develop a potentially life-threatening condition called eosinophilic meningitis. People usually catch these infections by eating raw or undercooked infected snails or by eating produce contaminated with snails.<\/p>\n The rat lungworm is endemic to parts of\u00a0Southeast Asia and the Pacific Islands, including\u00a0Hawaii<\/a>. But more recently, it\u2019s started to establish a foothold in other places, including within the continental U.S. Local cases have been reported so far in Louisiana, Florida, Oklahoma, Texas, and\u00a0Georgia<\/a>.<\/p>\n Officials at the San Diego Zoo first detected these worms inside the brain of a 7-year-old male Parma wallaby born and raised there in December 2024. The wallaby developed severe neurological illness and was euthanized 11 days into being hospitalized. Given the unusual discovery, they decided to examine the bodies of roof rats exterminated or found dead near the zoo between January and February 2025. Sixty-four rats were examined, two of which (3.1%) had lungworm.<\/p>\n Right around the same time, officials at a local wildlife rehabilitation program began to receive opossums with neurological illness possibly caused by rat lungworm infection. Ten of these opossums collected between 2023 and 2025 were examined after death, seven of which had eosinophilic meningitis and were infected with worms. Of these seven cases, six were infected by the lungworm.<\/p>\n The spread of rat lungworm <\/p>\n The researchers couldn\u2019t find lungworm infections among the snails they collected in the area (at least one snail had worm larvae, but they couldn\u2019t clearly identify the species). Still, the findings overall point to A. cantonensis having become endemic in Southern California. If so, it would reflect a disturbing expansion of the worm\u2019s range. Until now, local cases haven\u2019t been found in any continental state west of Texas, the researchers note.<\/p>\n \u201cFurther studies are needed to analyze the effect of this geographic expansion and associated risks in California,\u201d they wrote. \u201cNevertheless, [rat lungworm disease] should be part of the differential diagnosis for central nervous system disease in humans and animals in the wider southern United States.\u201d<\/p>\n Human rat lungworm infections are rare, and even most cases of eosinophilic meningitis will resolve without antiparasitic treatment (the worms tend to die off on their own). But it\u2019s one of many emerging diseases that could become more common in the U.S. and other countries as the climate warms, experts have warned<\/a>. It\u2019s also, as this report shows, a potential danger to animals in zoos and the wild.<\/p>\n","protected":false},"excerpt":{"rendered":"A brain-invading worm spread by rats and snails is making inroads into the United States. A study this…\n","protected":false},"author":2,"featured_media":509808,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[34],"tags":[97,47365,231377],"class_list":["post-509807","post","type-post","status-publish","format-standard","has-post-thumbnail","category-health","tag-health","tag-parasites","tag-rat-lungworm"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/509807","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/comments?post=509807"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/509807\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media\/509808"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media?parent=509807"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/categories?post=509807"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/tags?post=509807"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"25](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2026\/03\/25-1081-F1.jpg\")
Brain and cervical spinal cord tissue from the infected parma wallaby. The arrows point to the worms. \u00a9 Nakagun et al\/Emerging Infectious Diseases <\/p>\n