Angiostrongylus cantonensis
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Angiostrongylus cantonensis | |
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Scientific classification | |
Kingdom: | Animalia |
Phylum: | Nematoda |
Class: | Secernentea |
Order: | Strongylida |
Family: | Metastrongylidae |
Genus: | Angiostrongylus |
Species: | A. cantonensis |
Binomial name | |
Angiostrongylus cantonensis |
Angiostrongylus cantonensis is a parasitic nematode (roundworm) that causes Angiostrongyliasis, the most common cause of eosinophilic meningitis in Southeast Asia and the Pacific Basin.[1] The nematode commonly resides in the pulmonary arteries of rats, giving it the nickname the rat lungworm. Snails are the primary intermediate hosts, where larvae develop until they are infective. Humans are incidental hosts, and may become infected through ingestion of larvae in raw or undercooked snails or other vectors, or contaminated water and vegetables. The larvae are then transported via the blood to the central nervous system (CNS), where they are the most common cause of eosiniphilic meningitis, a serious condition that can lead to death or permanent brain and nerve damage.[2] Identified in 1964, Angiostrongyliasis is an infection of increasing public health importance as globalization aids in the geographic spread of the disease.
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Infectious agent
Angiostrongylus cantonensis is a helminth of the phylum Nematoda, order strongylida, and superfamily metastrongyloidea. Nematodes are roundworms characterized by a tough outer cuticle, unsegmented bodies, and a fully developed GI tract. The order Strongylida includes hookworms and lungworms. Metastrongyloidea are characterized as long, slender, threadlike worms that reside in the lungs of the definitive host.[3] Angiostrongylus costaricensis is a closely related worm that causes intestinal Angiostrongyliasis in Central and South America.
History of discovery
Nematodes suspected to be A. cantonensis were first identified in the cerebrospinal fluid of a patient with eosiniphilic meningitis by Nomura and Lim in Taiwan in 1944. They called the parasite Haemostrongylus ratti, and noted that raw food eaten by the patient may have been contaminated by rats. Their paper, however, was not translated from the original Japanese into English until just after the parasite had been recognized in 1964, so their discovery was not widely recognized.
In 1955, Mackerass and Sanders identified the life cycle of the worm in rats, defining snails and slugs as the intermediate host and noting the path of transmission through the blood, brain, and lungs in rats.
In 1961, an epidemiological study of eosiniphilc meningitis in humans was conducted by Rosen, Laigret, and Bories, who hypothesized that the parasite causing these infections was carried by fish. However Alicata noted that raw fish was consumed by large numbers of people in Hawaii without apparent consequences, and patients presenting with meningitis symptoms had a history of eating raw snails or prawns in the weeks before presenting with symptoms. This observation along with epidemiology and autopsy of infected brains confirmed A. cantonensis infection in humans as the cause of the majority of eosiniphilic meningitis cases in Southeast Asia and the Pacific Islands.[4]
Hosts
Intermediate hosts of larvae of for Angiostrongylus cantonensis include[5]:
- land snails: Thelidomus aspera from Jamaica,[6] Achatina fulica, Satsuma mercatoria, Acusta despecta, Bradybaena circulus and Parmarion martensi from Hawaii[7]
- freshwater snails: Pila sp.
- slugs: Limax maximus,[8] Deroceras laeve, Deroceras reticulatum, Laevicaulis alte, Vaginulus plebeius,[9] Lehmannia valentiana and other species of slugs.
Paratenic hosts of Angiostrongylus cantonensis include: predatory land flatworm Platydemus manokwari[5] and amphibians Bufo asiaticus, Rana catesbeiana, Rhacophorus leucomystax and Rana limnocharis.[5]
References
- ^ Baheti NN & Sreedharan M et al. (2008). "Eosinophilic meningitis and an ocular worm in a patient from Kerala, south India" J. Neurol. Neurosurg. Psychiatry 79 (271).
- ^ Hua Li, Feng Xu, Jin-Bao Gu and Xiao-Guang Chen (2008). "Case Report: A Severe Eosinophilic Meningoencephalitis Caused by Infection of Angiostrongylus cantonensis". Am. J. Trop. Med. Hyg., 79(4): 568–570.
- ^ http://www.path.cam.ac.uk/~schisto/helminth_taxonomy/taxonomy_nematoda.html, Accessed 2/26/09.
- ^ JE Alicata (1991). “The Discovery of Angiostrongylus Cantonensis as a Cause of Human Eosiniphilc Meningitis”. Parasitology Today, 7(6): 151-153.
- ^ a b c Asato R., Taira K., Nakamura M., Kudaka J., Itokazu K. & Kawanaka M. (2004) "Changing Epidemiology of Angiostrongyliasis Cantonensis in Okinawa Prefecture, Japan". Japanese Journal of Infectious Diseases 57: 184-186. article PDF
- ^ John F. Lindo, Cecilia Waugh, John Hall, Colette Cunningham-Myrie, Deanna Ashley, Mark L. Eberhard, James J. Sullivan, Henry S. Bishop, David G. Robinson, Timothy Holtz & Ralph D. Robinson. 2002. Enzootic Angiostrongylus cantonensis in Rats and Snails after an Outbreak of Human Eosinophilic Meningitis, Jamaica. Emerging Infectious Diseases, Volume 8, Number 3, March 2002.
- ^ Hollingsworth et al. 2007. Distribution of Parmarion cf. martensi (Pulmonata: Helicarionidae), a New Semi-Slug Pest on Hawai‘i Island, and Its Potential as a Vector for Human Angiostrongyliasis. Pacific Science 61(4):457-467. [1]
- ^ Sanjaya N. Senanayake, Don S. Pryor, John Walker & Pam Konecny 2003. First report of human angiostrongyliasis acquired in Sydney. The Medical Journal of Australia, 179 (8): 430-431.
- ^ http://web.archive.org/web/20071214020100/http://homepage.sunrise.ch/mysunrise/choegger/Slugs/Antagonists.html
External links
- Division of Parasitic Diseases, Centers for Disease Control and Prevention, Angiostrongylus cantonensis Infection
- Laboratory Identification of Parasites of Public Health Concern, Parasites and Health, Angiostrongyliasis
- Laboratory Identification of Parasites of Public Health Concern, Angiostrongyliasis Image Library
- MeSH Angiostrongylus+cantonensis
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