Angiostrongylus cantonensis		Contents		Rev 12/10/2024
Rat lungworm		Classification		Biology and Ecology
		Morphology and Anatomy		Life Cycle
Return to Angiostrongylus Menu				Ecosystem Functions and Services
		Distribution		Management
Return to Angiostrongylidae Menu		Feeding		References
		Go to Nemaplex Main Menu		Go to Dictionary of Terminology

Classification:

Chromadorea

  Rhabditia

    Rhabditida

      Metarongyloidea

        Angiostrongylidae

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Morphology and Anatomy:

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Distribution:

First described from rats in China by Chen in 1935.  Now found in many parts of the world; considered endemic in the Mediterranean region,  Hawaii ia an epicenter for human infections,

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Feeding:

  Rat lungworm infections and human angyostrongyliasis.

 Rats (Rattus spp.) are the definitive hosts while gastropods are intermediate hosts. In a Hawaiian study, 45.5% (197/433) of rats inspected had lung lobe(s) (mostly upper right) which appeared granular indicating this lobe may serve as a filter for worm passage to the rest of the lung. Across Rattus spp., 72.7% (396/545) were infected with adult worms, but 93.9% (512/545) of the rats were positive for A. cantonensis infection based on presence of live adult worms, encysted adult worms, L3 larvae and/or by PCR analysis of brain tissue.

The exceptionally high prevalence of A. cantonensis infection in Rattus spp. in east Hawaii Island is cause for concern and indicates the potential for human infection since this emerging zoonosis is greater than previously thought.

The disease in rats is characterized by symptoms ranging from mild (and possibly asymptomatic) from which the host may recover to eosinophilic meningitis and other severe debilitating comdition of the central nervous system. The effect on the central nervous system may result from an inflammatory reaction due to the migration to the brain and subsequent death of  A. cantonensis larvae. Extreme pain, vision impairment, paraesthesia, bowel disfunction, encephalitis followed by death have been reported (Jaume-Ramis et al., 2013).

The prevalence of A. cantonensis infection in humans is increasing, probably associated with the spread of the nematode

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Biology and Ecology:

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Life Cycle:

The adult stage of A. cantonensis is only found in rodents. Infected rodents can pass larvae of the worm in their feces. The infected feces are ingested by snails or slugs (intermediate hosts); it is also possible that the larvae enter the snail by penetrating the body wall or via the respiratory pore. The larvae develop to the third stage in the snails and remain at that stage until either the snail is eaten or dies. When snails carrying third stage larvae are eaten by a rat, they move through the rat gut to the small intestine where they penetrate the walls of the intestine and enter the blood stream. In the blood stream they travel passively and some eventually enter the central nervous system and the brain. In the brain, larvae develop to the sub-adult stage. Light infections appear to cause little damage to the brain and no obvious behavioral or other reaction, but heavy infections may cause more serious damage and behavioral symptoms. In the sub-adult stage ,the worms leave the brain, amd pass into the venous circulatory system, and thence to the right ventricle of the heart and to the pulmonary arteries where they mature, mate, and the females lay eggs. The eggs travel in the blood stream to the lungs (hence the name rat lungworm disease). They hatch into first stage larvae in the tissue of the lungs which may cause significant damage to the arteries, and to the lungs. The first stage larvae break through the walls of the bronchioles and alveoli, move up the trachea in respiratory secretions, and are swallowed, to be released in the feces. The cycle then repeats when snails ingest the infected feces. The cycle takes about 45 days.

Adapted from Crowe, 2013

Ecophysiological Parameters:

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Ecosystem Functions and Services:

Angiostrongyliasis, also known as neuroangiostrongyliasis or rat lungworm, is a disease that affects the brain and spinal cord of the host.

Humans can become infected with A. cantonensis if they eat (intentionally or otherwise) a raw or undercooked infected intermediate host, thereby ingesting the parasite.

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Management:

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References:

Jaume-Ramis, S., Martinez-Orti, A., Delgado-Serra, S., Bargues, M.D., Mas-Coma, S., Foronda, P., Paredes-Esquivel, C. 2023. Potential intermediate hosts of Angiostrongylus cantonensis in the European
Mediterranean region (Mallorca, Spain). One Health. 17 (2023) 100610

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Copyright © 1999 by Howard Ferris.
Revised: December 10, 2024.