Angiostrongyliasis is caused by infection and migration to the brain of larvae of the parasitic nematode Angiostrongylus cantonensis, or rat lungworm. Adult A. cantonensis reside in the lungs of the definitive wild rodent host, where they produce larvae passed in feces, which are then ingested by snails and slugs (gastropods). Human infection typically occurs when gastropods containing mature larvae are inadvertently ingested by humans. Although human infection often is asymptomatic or involves transient mild symptoms, larval migration to the brain can lead to eosinophilic meningitis, focal neurologic deficits, coma, and death. The majority of cases of human angiostrongyliasis occur in Asia and the Pacific Islands, including Hawaii, but autochthonous and imported cases have been reported in the continental United States (1,2), underscoring the importance of provider recognition to ensure prompt identification and treatment. The epidemiologic and clinical features of 12 angiostrongyliasis cases in the continental United States were analyzed. These cases were identified through A. cantonensis polymerase chain reaction (PCR) testing (3) of cerebrospinal fluid (CSF) submitted to CDC from within the continental United States. Six cases were likely a result of autochthonous transmission in the southern United States. All 12 patients had CSF pleocytosis and eosinophilia, consistent with eosinophilic meningitis. Health care providers need to be aware of the possibility of angiostrongyliasis in patients with eosinophilic meningitis, especially in residents in the southern United States or persons who have traveled outside the continental United States and have a history of ingestion of gastropods or contaminated raw vegetables.

Angiostrongyliasis is a food-borne parasitic disease caused by the nematode Angiostrongylus cantonensis that can lead to eosinophilic meningitis (EM) or meningoencephalitis in humans. Angiostrongylus cantonensis is prevalent in the Pacific Islands. In recent years, a large number of outbreaks and severe cases have occurred. Several species of mollusk, such as snails and slugs, act as intermediate and paratenic hosts of A. cantonensis. In this study, two cases of EM were found to have been caused by infection with A. cantonensis due to consumption of raw centipedes. To survey the A. cantonensis infections acquired through centipedes that the patients had bought at a vegetable market, we performed etiological examinations and polymerase chain reaction amplification of A. cantonensis genes. Third-instar larvae of A. cantonensis were detected in the centipedes, and specific genes from A. cantonensis were detected in all the specimens. This indicates that the centipede may act as a competent host for the transmission of A. cantonensis. To our knowledge, this is the first report of A. cantonensis infection through the consumption of centipedes.

Angiostrongylus cantonensis (rat lungworm), a parasitic nematode, is expanding its distribution. Human infection, known as angiostrongyliasis, may manifest as eosinophilic meningitis, an emerging infectious disease. The range and incidence of this disease are expanding throughout the tropics and subtropics. Recently, the Hawaiian Islands have experienced an increase in reported cases. This study addresses factors affecting the parasite's distribution and projects its potential future distribution, using Hawaii as a model for its global expansion. Specimens of 37 snail species from the Hawaiian Islands were screened for the parasite using PCR. It was present on five of the six largest islands. The data were used to generate habitat suitability models for A. cantonensis, based on temperature and precipitation, to predict its potential further spread within the archipelago. The best current climate model predicted suitable habitat on all islands, with greater suitability in regions with higher precipitation and temperatures. Projections under climate change (to 2100) indicated increased suitability in regions with estimated increased precipitation and temperatures, suitable habitat occurring increasingly at higher elevations. Analogously, climate change could facilitate the spread of A. cantonensis from its current tropical/subtropical range into more temperate regions of the world, as is beginning to be seen in the continental USA.

We report a case of eosinophilic meningitis complicated by transverse myelitis caused by Angiostrongylus cantonensis in a 10-year-old boy from Brazil who had traveled to Suriname. We confirmed diagnosis by serology and real-time PCR in the cerebrospinal fluid. The medical community should be aware of angiostrongyliasis in the Guiana Shield.

Eating of excessive raw or undercooked environmental snails produces Angiostrongyliasis demyelination caused by Angiostrongylus cantonensis. The aim of this study was to investigate the association between extracellular signal-regulated kinase (Erk)1/2-nuclear factor (NF)-κB pathway and myelin basic protein (MBP) expression in RSC 96 Schwann cells treated with A. cantonensis- conditioned culture medium, which was prepared by culturing the third-stage (L3) nematode larvae in DMEM for 72 h. The supernatants were collected and filtered before use. Our results showed that MBP was produced in the RSC 96 cells at 16 h to 48 h post-stimulation (PS). Phosphorylated (p)- NF-κB levels were significantly increased from 8 h to 48 h PS, as were the p-Erk1/2 levels at the same time points. Additionally, expression of p-NF-κB and MBP was significantly decreased by treatment with QNZ, an NF-κB inhibitor. Treatment with PD98059, an Erk kinase inhibitor, efficiently reduced p-Erk1/2, p-NF-κB and MBP expression in the Schwann cells. These results suggest that A. cantonensis-conditioned culture medium induced suppression of the Erk1/2-NF-κB signaling pathway leading to reduced MBP production in RSC 96 Schwann cells. Thus, inhibiting this signaling intermediate involved in MBP expression may be a potential method for controlling inflammatory development of A. cantonensis-induced MBP changes in preceded demyelination.

The terrestrial gastropod Bulimulus tenuissimus is widespread in South America. It is an intermediate host of many parasites, but there are no records of infection of this snail by Angiostrongylus cantonensis, despite the occurrence of this parasite and angiostrongyliasis cases in the same areas in which B. tenuissimus occurs. For this reason, it is important investigate the susceptibility of B. tenuissimus to A. cantonensis-infection, since it can be used as intermediate host of A. cantonensis, increasing the list of terrestrial gastropods that infect wild and domestic animals and humans with this parasite. The purpose of this study was to evaluate the susceptibility of B. tenuissimus to experimental infection with L1 larvae of A. cantonensis. The snails were exposed to 1200 L1 larvae and it was possible observe many developing larvae in the cephalopedal mass and mantle tissues, with intense hemocyte infiltration and collagen deposition, but no typical granuloma structures were formed. The glucose content and lactate dehydrogenase activity in the hemolymph varied, indicating an increase of anaerobic energy metabolism in the middle of infection, but with a tendency to return to normal values at the end of pre-patent period. This was corroborated by the marked reduction in the glycogen content in the cephalopedal mass and digestive gland in the first and second week after exposure, followed by a slight increase in the third week. The content of pyruvic acid in the hemolymph was 14.84% lower at the end of pre-patent period, and oxalic acid content was 41.14% higher. These results indicate an aerobic to anaerobic transition process. The PAS reaction showed a large amount of glycogen inside the developing larvae and muscular tissues of the cephalopedal mass, indicating that despite the high consumption of this polysaccharide by the parasite, the snail is able to maintain its energy metabolism based on carbohydrates. The results reveal that B. tenuissimus is a robust host, which can live with the developing larvae of A. cantonensis and overcome the metabolic damages resulting from parasitism.

Angiostrongyliasis, the leading cause worldwide of eosinophilic meningitis, is an emergent disease due to Angiostrongylus cantonensis larvae, transmitted accidentally to humans. Contamination of children usually occurs by direct contact with an infected mollusk. Eosinophilic meningoencephalitis is the major clinical feature of this parasitic infection in humans. It is usually benign for adults, but more severe for children. Clinical symptoms usually combine fever, meningitis, and neurological signs (somnolence, moaning, hypotonia, convulsions, and increased intracranial pressure). Presumptive diagnosis of human angiostrongyliasis is based on epidemiologic characteristics, clinical symptoms, medical history, and laboratory findings, in particular, hypereosinophilia in blood and cerebrospinal fluid. Treatment is based on corticosteroids associated with anthelmintics. This work reviews the diagnosis and treatment of this life-threatening (especially in children) parasitic disease and the need for preventive action.