Angiostrongylus cantonensis induces energy imbalance and dyskinesia in mice by reducing the expression of melanin-concentrating hormone.

BACKGROUND: Infection with Angiostrongylus cantonensis (AC) in humans or mice can lead to severe eosinophilic meningitis or encephalitis, resulting in various neurological impairments. Developing effective neuroprotective drugs to improve the quality of life in affected individuals is critical. METHODS: We conducted a Gene Ontology enrichment analysis on microarray gene expression (GSE159486) in the brains of AC-infected mice. The expression levels of melanin-concentrating hormone (MCH) were confirmed through real-time quantitative PCR (RT-qPCR) and immunofluorescence. Metabolic parameters were assessed using indirect calorimetry, and mice's energy metabolism was evaluated via pathological hematoxylin and eosin (H&E) staining, serum biochemical assays, and immunohistochemistry. Behavioral tests assessed cognitive and motor functions. Western blotting was used to measure the expression of synapse-related proteins. Mice were supplemented with MCH via nasal administration. RESULTS: Postinfection, a marked decrease in Pmch expression and the encoded MCH was observed. Infected mice exhibited significant weight loss, extensive consumption of sugar and white fat tissue, reduced movement distance, and decreased speed, compared with the control group. Notably, nasal administration of MCH countered the energy imbalance and dyskinesia caused by AC infection, enhancing survival rates. MCH treatment also increased the expression level of postsynaptic density protein 95 (PSD95) and microtubule-associated protein-2 (MAP2), as well as upregulated transcription level of B cell leukemia/lymphoma 2 (Bcl2) in the cortex. CONCLUSIONS: Our findings suggest that MCH improves dyskinesia by reducing loss of synaptic proteins, indicating its potential as a therapeutic agent for AC infection.

Efficacy of X-Ray Phytosanitary Irradiation on the Infectivity and Reproduction of Angiostrongylus cantonensis in Experimentally Infected Rats.

Angiostrongylus cantonensis is a globally distributed nematode and the leading cause of eosinophilic meningitis in humans. As a global hotspot for this disease, Hawaii's agricultural exports may be contributing to the spread of A. cantonensis. Phytosanitary irradiation doses of 150 or 400 Gy provide quarantine security against multiple insect pests. We evaluated the in vitro and in vivo effects of phytosanitary irradiation on infectious, third-stage, A. cantonensis larvae. In vitro experiments directly exposed larvae to irradiation doses ranging from 200 to 1,000 Gy. Results showed low mortality and no dose response across all treatments 27 days post-irradiation. In vivo studies isolated larvae from wild-caught Parmarion martensi after exposure to x-ray irradiation at doses of 0, 150, and 400 Gy and infected them into laboratory rats. Fourteen rats were assigned to each treatment and infected with 50 larvae from their assigned irradiation dose. Results at 3 and 6 weeks post-infection demonstrated a significant negative dose response in regard to the number of larvae that migrated to the brain and adults found in the pulmonary artery. No irradiated larvae that grew into adults were able to produce eggs. These findings indicate that x-ray irradiation does not result in the direct mortality of A. cantonensis larvae; however, it does affect the infectivity and reproduction of A. cantonensis within its definitive host, the rat. Phytosanitary irradiation at doses ≥150 Gy appears to be an effective means of preventing the establishment of viable populations of A. cantonensis, thus reducing the potential for global spread due to agricultural exports from Hawaii.

Molecular insights versus morphological traits: rethinking identification of the closely related Angiostrongylus cantonensis and Angiostrongylus malaysiensis.

BACKGROUND: The closely related Angiostrongylus cantonensis and Angiostrongylus malaysiensis have been reported to coexist in Thailand and share similar hosts and life cycles. Recently, in an angiostrongyliasis outbreak in Thailand, both A. cantonensis and A. malaysiensis were found in the cerebrospinal fluid of affected patients. Morphological similarities, overlapping distribution, shared hosts and habitats, and the close genetics of the two Angiostrongylus species can complicate accurate species identification. Addressing these challenges, this study aims to evaluate whether a correlation between the morphological and genetic identities of A. cantonensis and A. malaysiensis can improve species identification accuracy. METHODS: Angiostrongylus spp. specimens from five zoogeographical regions in Thailand were subjected to morphological and molecular identification using the mitochondrial cytochrome b gene and the nuclear internal transcribed spacer 2 region (ITS2). The morphological characters for males and females were then validated using the species identity obtained from the nuclear ITS2 region. RESULTS: The results revealed that morphological misidentifications between these two closely related species are common due to overlapping morphological characters. Although certain male traits such as body length and width aided species differentiation, female traits were found to be less reliable. Furthermore, hybrid forms (8.2%) were revealed through the ITS2 results, which can further complicate morphological identification. Mito-nuclear discordance was also present in 1.9% of the Angiostrongylus specimens from Thailand, suggesting a complex historical interbreeding between the species. CONCLUSIONS: Based on our findings, we suggest that nuclear ITS2 is a reliable marker for species identification of A. cantonensis and A. malaysiensis, especially in regions where both species coexist. Additionally, the scope and consequences of hybridization between the two closely related Angiostrongylus species should be further investigated in Thailand.

Population dynamics of Achatina fulica in a peri-urban area adjacent to the Fiocruz Atlantic Forest Biological Station (EFMA), in Rio de Janeiro, Brazil, with report on Angiostrongylus cantonensis infection.

Achatina fulica is a species native to East Africa, considered one of the 100 worst invasive alien species in the world. The present study investigated the population of the snail, A. fulica, in a peri-urban area adjacent to the Fiocruz Atlantic Forest Biological Station (EFMA), in Jacarepaguá, Rio de Janeiro state, Brazil, focusing on population dynamics and the nematodes associated with this species. To this end, specimens were collected during four climatic seasons of the years 2021 and 2022 in three fixed 20 m × 10 m plots. The abundance of A. fulica in these areas was evaluated in relation to a set of environmental variables (temperature, relative humidity air, and soil pH and calcium). The abundance of snails infected by nematodes was also evaluated in relation to the season and body size of the specimens. The molluscs were found by active search, and standardized (15 minutes/three collections). Nematode larvae were extracted from the specimens by artificial digestion and identified by their external morphology and the sequencing of molecular markers. A total of 280 specimens of A. fulica were collected, with the highest abundances being recorded in the autumn and summer, although no significant relationship was found between the number of specimens collected and the environmental variables. Overall, 192 snails were infected by nematodes: Angiostrongylus cantonensis, Cruzia tentaculata and free-living nematodes, including Caenorhabditis briggsae. These findings demonstrate the epidemiological importance of the study area and the need to implement educational measures in the community, with the aim of controlling the local A. fulica population, thereby minimizing the risk of parasitic infection in the local human population.

Semperula wallacei (Mollusca, Veronicellidae) um hospedeiro natural recém-descoberto de Angiostrongylus cantonensis (Nematoda, Angiostrongylidae) na Bacia do Pacífico.

Semperula wallacei (Issel, 1874) is a species of terrestrial slug that occurs in southeast China and the Pacific Basin and is the only species of its genus that occurs beyond the Oriental region and to the east of Wallace's line in the Australian region, where it has probably been introduced. In this study, we report for the first time S. wallacei as an intermediate host for Angiostrongylus cantonensis (Chen, 1935) based on histological and molecular analyses of slugs from Tuamasaga, Samoa, deposited at the Medical Malacological Collection (Fiocruz-CMM). DNA was obtained from the deparafinized tissues scraped from specimen slides. Polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) targeted to the internal transcribed spacer 2 (ITS2) region were carried out using the restriction enzyme Cla I. The RFLP profile observed for our larval specimen of S. wallacei was identical to the profile previously established for A. cantonensis, demonstrating that S. wallacei can be naturally infected with A. cantonensis and is likely to be an intermediate host for this parasitic nematode species in the field. The potential for geographical range expansion of S. wallacei in the Pacific Basin, its small size, and the general role of veronicellids as crop pests and hosts of nematodes, indicate the significance of S. wallacei as an invasive species in the Pacific Basin. Our work also highlights the importance of biological collections for investigating the environmental impact of invasive species on agriculture, public health, and biodiversity conservation.

Molecular Diagnosis of Severe Angiostrongylus cantonensis-Induced Eosinophilic Meningitis: A Case Report Emphasizing the Need for Accurate Detection Methods.

BACKGROUND Angiostrongylus cantonensis, also known as the rat lungworm, is the most common parasitic cause of human eosinophilic meningitis. A. cantonensis infection is an emergent disease causing permanent neurological injury or even death when not diagnosed and treated promptly. Usually, human infection occurs through ingestion of food contaminated by intermediated hosts or the third stage larvae of A. cantonensis. Indicators for diagnosis include clinical signs of meningitis; contact history, such as that from eating raw or improperly cooked intermediated hosts or contaminated vegetables; and cerebrospinal fluid (CSF) eosinophilia. However, diagnosis is now primarily defined through polymerase chain reaction (PCR) assay of CSF or serum. CASE REPORT A 66-year-old homeless man with unclear exposure history presented with fever and conscious change. The initial hemogram showed eosinophilia without neutrophilic leukocytosis. Non-contrast computed tomography (CT) and magnetic resonance imaging (MRI) of the head revealed no evidence of stroke. A lumbar puncture was performed and showed eosinophilic meningitis. The patient was ultimately diagnosed through PCR and sequencing for A. cantonensis infection, and dexamethasone treatment was started immediately. Although his general condition improved after dexamethasone treatment, his mental status did not improve completely. CONCLUSIONS Our report highlights the importance of applying molecular techniques in diagnosis of angiostrongylosis, especially in individuals who have unknown contact history.

[Health implications of the finding of Angiostrongylus cantonensis, the main cause of eosinophilic meningoencephalitis, in continental Europe (Valencia, Spain)]. / Implicaciones sanitarias del hallazgo de Angiostrongylus cantonensis, causa principal de la meningoencefalitis eosinofílica, en Europa continental (València, España).

The rat pulmonary artery nematode, Angiostrongylus cantonensis (discovered in rats from the province of Canton, southern China, in 1933 ) is the main cause in humans of what is known as eosinophilic meningoencephalitis (EEM), with around of 3,000 confirmed cases in various parts of the world.

El nematodo de las arterias pulmonares de las ratas, Angiostrongylus cantonensis (descubierto en ratas de la provincia de Cantón, en el sur de China, en 1933  es el principal responsable en el ser humano de la conocida como meningoencefalitis eosinofílica (MEE), con alrededor de 3.000 casos confirmados en diversas partes del mundo.

[Progress of researches on the role and mechanisms of non - coding RNA in Angiostrongylus cantonensis infection].

Angiostrongylus cantonensis is a food-borne zoonotic parasite, and human infection may cause eosinophilic meningitis. Non-coding RNAs (ncRNAs) may regulate physiological and pathological processes at multiple biological levels; however, there are few studies pertaining to the regulatory role of ncRNAs in A. cantonensis infection. Based on publications retrieved from PubMed, Wanfang Data and CNKI, the regulatory role of ncRNAs in A. cantonensis infections mainly includes immune responses, cell apoptosis and signaling transduction, and ncRNAs may serve as biomarkers for diagnosis of angiostrongyliasis. This review summarizes the main roles of ncRNAs in A. cantonensis infections and the underlying mechanisms, so as to provide insights into diagnosis and treatment of angiostrongyliasis.

The global risk of infectious disease emergence from giant land snail invasion and pet trade.

BACKGROUND: Pathogen outbreaks mostly originate from animals, but some species are more likely to trigger epidemics. The giant land snail (Lissachatina fulica) is a widespread invader, a popular exotic pet, and a notorious vector of the rat lungworm, causing eosinophilic meningitis in humans. However, a comprehensive assessment of the risks of disease outbreak associated with this species is lacking. METHODS: We assessed and mapped the risk of disease transmission associated with the invasion and pet trade of L. fulica. First, we conducted a review of the scientific literature to list all known L. fulica parasites and pathogens and query host-pathogen databases to identify their potential mammalian hosts. Then, to assess the potential for L. fulica to spread globally, we modelled its suitable climatic conditions and tested whether, within climatically suitable areas, the species tended to occur near humans or not. Finally, we used social media data to map L. fulica possession as an exotic pet and to identify human behaviours associated with increased risk of disease transmission. RESULTS: Lissachatina fulica can carry at least 36 pathogen species, including two-thirds that can infect humans. The global invasion of L. fulica is climatically limited to tropical areas, but the species is strongly associated with densely populated areas where snails are more likely to enter in contact with humans. In temperate countries, however, climatic conditions should prevent L. fulica's spread. However, we show that in Europe, giant snails are popular exotic pets and are often handled with direct skin contact, likely increasing the risk of pathogen transmission to their owners. CONCLUSIONS: It is urgent to raise public awareness of the health risks associated with L. fulica in both tropical countries and Europe and to regulate its trade and ownership internationally. Our results highlight the importance of accounting for multiple types of human-wildlife interactions when assessing risks of infectious disease emergence. Furthermore, by targeting the species most likely to spread pathogens, we show that it is possible to rapidly identify emerging disease risks on a global scale, thus guiding timely and appropriate responses.

Protective effect of benzaldehyde combined with albendazole against brain injury induced by Angiostrongylus cantonensis infection in mice.

Angiostrongylus cantonensis, also known as rat lungworm, is an important food-borne zoonotic parasite that causes severe neuropathological damage and symptoms, including eosinophilic meningitis and eosinophilic meningoencephalitis, in humans. At present, the therapeutic strategy for cerebral angiostrongyliasis remains controversial. Benzaldehyde, an important bioactive constituent of Gastrodia elata (Tianma), reduces oxidative stress by inhibiting the production of reactive oxygen species. This study aimed to evaluate the therapeutic effect of benzaldehyde in combination with albendazole on angiostrongyliasis in animal models. First, the data from body weight monitoring and behavioural analyses demonstrated that benzaldehyde improved body weight and cognitive function changes after A. cantonensis infection. Next, blood‒brain barrier breakdown and pathological changes were reduced after benzaldehyde and albendazole treatment in BALB/c mice infected with A. cantonensis. Subsequently, four RNA-seq datasets were established from mouse brains that had undergone different treatments: normal, infection, infection + albendazole, and infection + albendazole + 3-hydroxybenzaldehyde groups. Ultimately, benzaldehyde was found to regulate cell apoptosis, oxidative stress and Sonic Hedgehog signalling in mouse brains infected with A. cantonensis. This study evaluated the therapeutic effect of benzaldehyde on angiostrongyliasis, and provided a potential therapeutic strategy for human angiostrongyliasis in the clinical setting. Moreover, the molecular mechanism of benzaldehyde in mouse brains infected with A. cantonensis was elucidated.

IgE antibody responses in cerebrospinal fluids relate to the brain pathologic injury of hosts with Angiostrongylus cantonensis infection.

BACKGROUND: The immunoglobulin E (IgE) response to Angiostrongylus cantonensis infection increases in the host. This study analyzed the IgG and IgE responses detected in different body fluids of A. cantonensis-infected mice. METHODS: BALB/c (high susceptibility), CBA (medium), and C57BL/6 and C57BL/10 (resistance) strain mice were used in this study. The levels of IgM, IgG, and IgE in the serum and cerebrospinal fluid (CSF) from infected mice were compared. A. cantonensis-reactive antigens from BALB/c and C57BL/6 mice CSF were also analyzed. RESULTS: Antibodies against fifth-stage larvae (L5) antigens increased in mice CSF, particularly IgE, relate to worm rejection and the susceptibility of different mouse strains. The increased IgE level in BALB/c mice CSF is lower than that from others, suggesting IgE response in brain is more important than that in serum. Anti-L5 and anti-excretory/secretory (ES) antigen IgE and IgG responses in CSF were analyzed. In addition, the antibody-dependent eosinophil-mediated cytotoxicity induced by anti-excretory/secretory (ES) antigen antibodies may be the reason of severe brain inflammation in infected BALB/c mice. IgE and IgG antibodies against a 105 kDa protein of L5 antigen was detected at week 3 post-infection in C57BL/6 mice and week 5 post-infection in BALB/c mice. We suggest that 105 kDa protein is related with the antibody response of A. cantonensis-infected mice. CONCLUSION: We found that IgE antibodies in mice CSF against L5 antigens related to worm rejection in mice brains. This study may help to identify specific angiostrongyliasis markers that can be applied for clinical diagnosis and treatment in future.

Angiostrongylus cantonensis Infection in Brown Rats (Rattus norvegicus), Atlanta, Georgia, USA, 2019-2022.

Rat lungworm (Angiostrongylus cantonensis), a zoonotic parasite invasive to the United States, causes eosinophilic meningoencephalitis. A. cantonensis harbors in rat reservoir hosts and is transmitted through gastropods and other paratenic hosts. We discuss the public health relevance of autochthonous A. cantonensis cases in brown rats (Rattus norvegicus) in Atlanta, Georgia, USA.

Rat lungworm survives winter: experimental overwintering of Angiostrongylus cantonensis larvae in European slugs.

The rat lungworm Angiostrongylus cantonensis is a metastrongyloid nematode that causes neurological disorders in its accidental hosts, including humans. This invasive pathogen is native to Southeast Asia and adjacent regions and is gradually expanding its distribution to tropical and subtropical areas with new foci discovered near temperate regions. The parasite has a complex life cycle with a range of gastropods serving as intermediate hosts. A broad spectrum of poikilotherm vertebrates and invertebrates can serve as paratenic hosts. Since it has already been demonstrated that other, non-zoonotic metastrongyloids can survive in their intermediate hosts during the winter, the aim of our study was to evaluate the survival of A. cantonensis third-stage larvae in experimentally infected slugs (Limax maximus) kept at 4.5­7°C for 60 days. Third-stage larvae of A. cantonensis survived the period of low temperature and remained capable of infecting definitive hosts (laboratory rats) afterwards, even though their numbers dropped significantly. These results suggest that further spread to higher latitudes or altitudes is possible in areas with sufficient abundance of definitive hosts, since low winter temperatures are not necessarily an obstacle to the spread of the parasite.

The recent introduction of Angiostrongylus cantonensis and its intermediate host Achatina fulica into Guadeloupe detected by phylogenetic analyses.

BACKGROUND: Angiostrongylus cantonensis (rat lungworm) is the main pathogen responsible for eosinophilic meningitis in humans. One of its intermediate snail hosts, Achatina fulica, was already present in many countries around the world before it appeared in the West Indies in the late 1980s. In the French territories in the Caribbean and northern South America, the first cases of human neuroangiostrongyliasis were reported in Martinique, Guadeloupe and French Guiana in 2002, 2013 and 2017, respectively. In order to better characterize angiostrongyliasis in Guadeloupe, particularly its geographical origin and route of introduction, we undertook molecular characterization of adult worms of Angiostrongylus cantonensis and its intermediate host Achatina fulica. METHODS: Genomic DNA of adult Angiostrongylus cantonensis and Achatina fulica was extracted and amplified by polymerase chain reaction (PCR) targeting the mitochondrial genes cytochrome B and C for A. cantonensis and 16S ribosomal RNA for A. fulica. The PCR products were sequenced and studied by phylogenetic analysis. RESULTS: Cytochrome B and cytochrome C molecular markers indicate a monophyletic lineage of A. cantonensis adult worms in Guadeloupe. Two sequences of A. fulica were identified. CONCLUSIONS: These results confirm the recent introduction of both Angiostrongylus cantonensis and Achatina fulica into Guadeloupe. Achatina fulica in Guadeloupe shares a common origin with those in Barbados and New Caledonia, while Angiostrongylus cantonensis in Guadeloupe shares a common origin with those in Brazil, Hawaii and Japan.

Clinical Characteristics and Treatment Outcome of Eosinophilic Meningoencephalitis in South Indian Children: Experience From a Prospective Registry.

BACKGROUND: To describe the clinical features and therapeutic outcomes of a prospective cohort of children with eosinophilic meningoencephalitis. METHODS: Children admitted with clinical features suggestive of meningitis along with cerebrospinal fluid (CSF) eosinophilia during the period of 14 years (2008 to 2021) were included. Their baseline characteristics, epidemiologic associations, and treatment outcomes were analyzed and compared with the previous studies. RESULTS: We identified 25 children (13 males) satisfying the inclusion criteria. The median age at presentation was 3.9 years (range 0.8 to 17 years); 68% were aged less than two years. Fourteen (56%) children had a history of exposure to snails. Most of them presented with fever, headache, irritability, lateral rectus palsy, and early papilledema. Symptoms started three to 42 days (median duration: 14 days) before admission to our center. All children had peripheral eosinophilia, which ranged from 9% to 41%. The mean CSF white blood cell count was 416/mm3 (range 50 to 1245 cells/mm3) with CSF eosinophilia ranging from 11% to 80%. Brain magnetic resonance imaging was done in 24 children and was normal in 15 (62.5%). Leptomeningeal enhancement was seen in two (8.3%) children, and other nonspecific changes were noted in seven (29.1%) children. All children recovered without any neurological deficits with a standard treatment regimen of albendazole and oral steroids. All were asymptomatic at the last follow-up. None of them had any recurrence during the follow-up period. CONCLUSION: We report one of the largest clinical series of children with eosinophilic meningoencephalitis from an endemic area of South India.

[Prevalence of Angiostrongylus cantonensis infection in snails in Fujian Province from 2017 to 2021].

OBJECTIVE: To investigate the prevalence of Angiostrongylus cantonensis infection in market-sold and field-captured snails in Fujian Province, so as to provide the scientific basis for the formulation of the angiostrongyliasis control measures. METHODS: In each month from May to October during the period from 2017 through 2021, Pomacea snails were collected from two field fixed surveillance sites and Bellamya aeruginosa collected from one agricultural product market in Fuzhou City, while Pomacea and B. aeruginosa snails were collected from two agricultural product markets and four restaurants in Xiamen City. At least 50 Pomacea snails and 500 g B. aeruginosa were sampled each time. A. cantonensis infection was detected in Pomacea snails using lung microscopy, and in B. aeruginosa using a tissue homogenate method. RESULTS: A total of 9 531 Pomacea snails were detected for A. cantonensis infection in two cities of Fuzhou and Xiamen, and the overall prevalence of A. cantonensis infection was 4.40%, with the highest prevalence in 2017 (6.82%, 116/1 701) and the lowest prevalence in 2019 (3.46%, 83/2 400). The prevalence of A. cantonensis infection was significantly higher in Pomacea snails sampled from Fuzhou City (11.23%, 326/2 903) than from Xiamen City (1.40%, 93/6 628) (χ2 = 461.48, P < 0.01). A. cantonensis larvae were detected in larval Pomacea snails in two cities of Fuzhou and Xiamen each month. The prevalence of A. cantonensis infection in Pomacea snails appeared an overall tendency towards a rise with month in Fuzhou City, with the highest prevalence in October (15.24%), and there was a significant difference among month (χ2 = 14.56, P < 0.05), while the prevalence of A. cantonensis infection in Pomacea snails was low in Pomacea snails sampled from Xiamen City each month, with the highest prevalence in June (2.64%), and there was a significant difference among month (χ2 = 23.17, P < 0.05). A total of 18 966 B. aeruginosa snails were detected for A. cantonensis infection in two cities of Fuzhou and Xiamen, and the overall prevalence of A. cantonensis infection was 0.01%. CONCLUSIONS: A. cantonensis infection was identified in Pomacea and B. aeruginosa snails in Fujian Province from 2017 to 2021, and there is a potential risk of human A. cantonensis infection.

[Progress of researches on techniques for detection of Angiostrongylus cantonensis in intermediate host snails].

Angiostrongyliasis cantonensis is an emerging infectious disease in China. Snails are intermediate hosts of Angiostrongylus cantonensis and play a critical role in the transmission of angiostrongyliasis cantonensis. Detection of A. cantonensis in snails is an important part of epidemiological surveys. Currently, the rapid developments in the techniques for detection of A. cantonensis in snails facilitate the surveillance of angiostrongyliasis cantonensis and provide an important support for angiostrongyliasis cantonensis prevention and control. This review summarizes the advances in the techniques for detection of A. cantonensis in snails.

Identification and genetic characterization of Angiostrongylus cantonensis isolated from the human eye.

Angiostrongylus cantonensis, or the rat lungworm, is the causative agent of human angiostrongyliasis associated with eosinophilic meningitis or meningoencephalitis. Additionally, this nematode can cause ocular angiostrongyliasis, though this is rare. The worm can cause permanent damage to the affected eye and sometimes even blindness. Genetic characterization of the worm from clinical samples is limited. In the present study, we investigated the genetics of A. cantonensis recovered from a patient's eye in Thailand. We sequenced two mitochondrial genes (cytochrome c oxidase subunit I, or COI, and cytochrome b, or cytb) and nuclear gene regions (66-kDa protein and internal transcribed spacer 2, or ITS2) from a fifth-stage larva of Angiostrongylus sample that was surgically removed from the human eye. All sequences of the selected nucleotide regions were highly similar (98-100%) to the sequences of A. cantonensis in the GenBank database. The maximum likelihood and neighbor-joining trees of the COI gene indicated that A. cantonensis was closely related to the AC4 haplotype, whereas the cytb and 66-kDa protein genes were closely clustered with the AC6 and Ac66-1 haplotypes, respectively. In addition, the phylogeny of the concatenated nucleotide datasets of the COI and cytb revealed that the worm was closely related to the Thai strain and strains from other countries. This study confirms the identification and genetic variation of the fifth-stage larvae of A. cantonensis recovered from a patient's eye in Thailand. Our findings are important for future research on the genetic variation of A. cantonensis that causes human angiostrongyliasis.

A cross-sectional study of Angiostrongylus malaysiensis in rats and gastropod hosts from recreational parks in Kuala Lumpur, Malaysia: Detection, risk factors and pathology.

Angiostrongylus malaysiensis is a potential zoonotic parasite, which reported to co-occur with A. cantonensis in human cerebrospinal fluid. It is a heteroxenous nematode that primarily develops through the early larval stages in gastropods and attains sexual maturity within rats. This study was conducted to determine the host species responsible for the reservoir of A. malaysiensis and investigate the risk factor for transmission among the hosts in Kuala Lumpur, Malaysia. Sampling was conducted in six recreational parks. The rats were trapped alive using steel wire traps with bait, while the gastropods were collected by active searching. The rats were euthanized and dissected to collect any adult worms observed. The molecular detection of A. malaysiensis was performed by PCR on gastropod tissue samples. Biotic and landscape factors were recorded for risk factor analysis. In total, 82 rats and 330 gastropods were collected throughout the study. Overall, 3.64% of gastropods and 32.9% of rats were infected with A. malaysiensis. Rattus tiomanicus (Malayan wood rat) and Parmarion martensi (Yellow-shelled semi-slug) were found as important hosts for A. malaysiensis. Host species, sampling site and macrohabitat type are risk factors associated with the prevalence of A. malaysiensis infection in rats. For gastropods, host species and sampling site are risk factors that correlate with the parasite detection. In total, 128 adult A. malaysiensis were recovered from the infected rats. The mean intensity of infection with adult A. malaysiensis was 4.65 for Rattus rattus complex and 4.90 for R. tiomanicus. Adult worms were found in the pulmonary artery or right ventricle, while eggs and first-stage larvae were found in capillaries of the caudal lung lobe. Infected lungs showed extravasated red blood cells in the alveolar spaces. The pulmonary arteries in the infected lung lobe were thickened. Kepong Metropolitan Park is the hotspot area for A. malaysiensis in Kuala Lumpur. These results provide essential information for public health officials to develop targeted interventions to reduce the transmission of A. malaysiensis in urban areas, particularly in recreational parks.

Immunodiagnostic Detection of Angiostrongylus cantonensis Exposure on Hawaii Island Using Isogeographic 31-kDa Antigen.

Angiostrongylus cantonensis is the leading cause of neuroangiostrongyliasis worldwide, and east Hawaii Island is a hotspot for the disease in the United States. A combination of glycoproteins with molecular weight of 31 kDa has been used as antigen to evaluate antibody response in human serum samples in Thailand with high specificity and sensitivity. In a previous pilot study, the Thailand-isolated 31-kDa proteins showed efficacy in dot-blot tests using serum samples from 435 human volunteers on Hawaii Island. However, we hypothesized that native antigen isolated from Hawaii A. cantonensis may exhibit higher specificity than the Thailand-isolated 31-kDa antigen due to potential minor variation in epitopes between isolates. In this study, 31-kDa glycoproteins were isolated by sodium dodecyl-sulfate polyacrylamide gel electrophoresis from adult A. cantonensis nematodes collected from rats captured on east Hawaii Island. The resultant proteins were purified by electroelution, pooled, bioanalyzed, and quantified. A subset of 148 samples from human participants of the original cohort of 435 was consented for this study, including 12 of the original 15 clinically diagnosed participants. Results of ELISA using the Hawaii-isolated 31-kDa antigen were compared with results of the same serum samples previously tested with both crude Hawaii antigen ELISA and Thailand 31-kDa antigen dot blot. This study shows a seroprevalence in the general population of East Hawaii Island of 25.0%, similar to previous findings of 23.8% seroprevalence in this cohort using crude antigen from Hawaii A. cantonensis and 26.5% using Thailand 31-kDa antigen.