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Invasive Snails and an Emerging Infectious Disease: Results from the First National Survey on Angiostrongylus cantonensis in China  [PDF]
Shan Lv,Yi Zhang,He-Xiang Liu,Ling Hu,Kun Yang,Peter Steinmann,Zhao Chen,Li-Ying Wang,Jürg Utzinger,Xiao-Nong Zhou
PLOS Neglected Tropical Diseases , 2009, DOI: 10.1371/journal.pntd.0000368
Abstract: Background Eosinophilic meningitis (angiostrongyliasis) caused by Angiostrongylus cantonensis is emerging in mainland China. However, the distribution of A. cantonensis and its intermediate host snails, and the role of two invasive snail species in the emergence of angiostrongyliasis, are not well understood. Methodology/Principal Findings A national survey pertaining to A. cantonensis was carried out using a grid sampling approach (spatial resolution: 40×40 km). One village per grid cell was randomly selected from a 5% random sample of grid cells located in areas where the presence of the intermediate host snail Pomacea canaliculata had been predicted based on a degree-day model. Potential intermediate hosts of A. cantonensis were collected in the field, restaurants, markets and snail farms, and examined for infection. The infection prevalence among intermediate host snails was estimated, and the prevalence of A. cantonensis within P. canaliculata was displayed on a map, and predicted for non-sampled locations. It was confirmed that P. canaliculata and Achatina fulica were the predominant intermediate hosts of A. cantonensis in China, and these snails were found to be well established in 11 and six provinces, respectively. Infected snails of either species were found in seven provinces, closely matching the endemic area of A. cantonensis. Infected snails were also found in markets and restaurants. Two clusters of A. cantonensis–infected P. canaliculata were predicted in Fujian and Guangxi provinces. Conclusions/Significance The first national survey in China revealed a wide distribution of A. cantonensis and two invasive snail species, indicating that a considerable number of people are at risk of angiostrongyliasis. Health education, rigorous food inspection and surveillance are all needed to prevent recurrent angiostrongyliasis outbreaks.
Loop-mediated isothermal amplification: rapid detection of Angiostrongylus cantonensis infection in Pomacea canaliculata
Rui Chen, QunBo Tong, Yi Zhang, Di Lou, QingMing Kong, Shan Lv, MingMing Zhuo, LiYong Wen, ShaoHong Lu
Parasites & Vectors , 2011, DOI: 10.1186/1756-3305-4-204
Abstract: We used a loop-mediated isothermal amplification (LAMP) assay, which was performed using Bst DNA polymerase. Reactions amplified the A. cantonensis 18S rRNA gene and demonstrated high sensitivity; as little as 1 fg of DNA was detected in the samples. Furthermore, no cross-reactivity was found with other parasites such as Toxoplasma gondii, Plasmodium falciparum, Schistosoma japonicum, Clonorchis sinensis, Paragonimus westermani and Anisakis. Pomacea canaliculata snails were exposed to A. cantonensis first-stage larvae (L1) in the laboratory, and L3 were observed in the snails thirty-five days after infection. All nine samples were positive as determined by the LAMP assay for A. cantonensis, which was identified as positive by using PCR and microscopy, this demonstrates that LAMP is sensitive and effective for diagnosis.LAMP is an appropriate diagnostic method for the routine identification of A. cantonensis within its intermediate host snail P. canaliculata because of its simplicity, sensitivity, and specificity. It holds great promise as a useful monitoring tool for A. cantonensis in endemic regions.Angiostrongylus cantonensis can be found in the lungs and arteries of insectivores, rodents, canines and felines [1-6]. They are prevalent in the Pacific islands and Southeast Asia, and are the most common cause of eosinophilic meningitis in humans in areas where the parasite is endemic [7]. The definitive hosts of A. cantonensis are various species of rats. Modes of transmission of this parasite include ingestion of raw or undercooked snails and fresh leafy vegetables contaminated by infective third-stage larvae (L3) [8]. First-stage larvae (L1) of A. cantonensis grow to infective L3 in intermediate host snails. This disease is difficult to detect because of the long incubation period in patients and few diagnostic symptoms. Thus, in order to control A. cantonensis, efforts should be directed towards building a surveillance system for the intermediate host snails of th
Neuroimmunological findings of Angiostrongylus cantonensis meningitis in ecuadorian patients
Dorta-Contreras, Alberto J.;Padilla-Docal, Barbara;Moreira, Juan M.;Robles, Luiggi Martini;Aroca, Jenny Muzzio;Alarcón, Fernando;Bu-Coifiu- Fanego, Raisa;
Arquivos de Neuro-Psiquiatria , 2011, DOI: 10.1590/S0004-282X2011000400011
Abstract: meningitis caused by angiostrongylus cantonensis has recently been reported in patients resulting from the first outbreaks in subtropical regions of ecuador. method: eight young adult patients from the two outbreaks were studied. iga, igm, igg and albumin in cerebrospinal fluid and serum were quantified and plotted in cerebrospinal fluid/serum quotient diagrams (reibergrams). the anamnesis on the patients included asking about any consumption of raw snails, symptoms and harm caused. results: mean eosinophilia of 7.5% and 26% in serum and cerebrospinal fluid respectively was observed, as well as a moderate increase in total proteins. the most frequent pattern of intrathecal synthesis was observed in three classes of immunoglobulins. intrathecal synthesis of igm was observed in all cases two weeks after the first symptoms appeared. conclusion: the intrathecal synthesis patterns of eosinophilic meningitis due to angiostrongylus cantonensis, facilitated by cerebrospinal fluid analysis, were similar to those of previous cases from abroad.
Eosinophilic meningitis due to Angiostrongylus cantonensis  [cached]
Panackel C,Vishad,Cherian G,Vijayakumar K
Indian Journal of Medical Microbiology , 2006,
Abstract: Angiostrongylus cantonensis is a nematode parasite that inhabits the pulmonary arteries and heart of rodents. It is one of the causative agents of fatal eosinophilic meningoencephalitis in man. We present five cases of eosinophilic meningitis presumably due to infection with Angiostrongylus cantonensis . All the five patients gave history of ingestion of monitor lizard within ten days of onset of symptoms.
Preliminary molecular characterization of the human pathogen Angiostrongylus cantonensis
Hualiang He, Mei Cheng, Xiao Yang, Jinxiu Meng, Ai He, Xiaoying Zheng, Zhuoya Li, Pengjuan Guo, Zhihua Pan, Ximei Zhan
BMC Molecular Biology , 2009, DOI: 10.1186/1471-2199-10-97
Abstract: A cDNA library of A. cantonensis fourth-stage larvae was constructed, and ~1,200 clones were sequenced. Bioinformatic analyses revealed 378 cDNA clusters, 54.2% of which matched known genes at a cutoff expectation value of 10-20. Of these 378 unique cDNAs, 168 contained open reading frames encoding proteins containing an average of 238 amino acids. Characterization of the functions of these encoded proteins by Gene Ontology analysis showed enrichment in proteins with binding and catalytic activity. The observed pattern of enzymes involved in protein metabolism, lipid metabolism and glycolysis may reflect the central nervous system habitat of this pathogen. Four proteins were tested for their immunogenicity using enzyme-linked immunosorbent assays and histopathological examinations. The specificity of each of the four proteins was superior to that of crude somatic and excretory/secretory antigens of larvae, although their sensitivity was relatively low. We further showed that mice immunized with recombinant cystatin, a product of one of the four cDNA candidate genes, were partially protected from A. cantonensis infection.The data presented here substantially expand the available genetic information about the human pathogen A. cantonensis, and should be a significant resource for angiostrongyliasis researchers. As such, this work serves as a starting point for molecular approaches for diagnosing and controlling human angiostrongyliasis.Angiostrongylus cantonensis was first discovered in the pulmonary arteries and hearts of domestic rats in Guangzhou (Canton), China, by Chen in 1935 [1]. This metastrongyloid nematode is now well recognized as the primary cause of human eosinophilic meningoencephalitis (EME) in many parts of the Indo-Pacific region [2,3]. Rats, the permissive or definitive host, acquire this nematode by ingesting the third-stage (L3) larvae. Humans, as accidental hosts, become infected by eating raw or improperly cooked freshwater snails, the intermedia
First record of molluscs naturally infected with Angiostrongylus cantonensis (Chen, 1935) (Nematoda: Metastrongylidae) in Brazil
Caldeira, Roberta Lima;Mendon?a, Cristiane LGF;Goveia, Christiane Oliveira;Lenzi, Henrique L;Graeff-Teixeira, Carlos;Lima, Walter S;Mota, Ester M;Pecora, Iracy Lea;Medeiros, Aline Maria Zigiotto de;Carvalho, Omar dos Santos;
Memórias do Instituto Oswaldo Cruz , 2007, DOI: 10.1590/S0074-02762007000700018
Abstract: seeking the identification of angiostrongylus cantonensis as a potential etiological agent of three clinical cases of eosinophilic meningitis, mollusc specimens were collected in the state of espírito santo, brazil. the snails were identified as sarasinula marginata (45 specimens), subulina octona (157), achatina fulica (45) and bradybaena similaris (23). larvae obtained were submitted to polymerase chain reaction and restriction fragment length polymorphism diagnosis. their genetic profile were corresponded to a. cantonensis. rattus norvegicus experimentally infected with third-stage larvae, developed menigoencephalitis, and parasites became sexually mature in the lungs. additionally, larvae obtained from a. fulica snails, from s?o vicente, state of s?o paulo, also showed genetic profiles of this nematode. this is the first record of brazilian molluscs infected with this nematode species.
Mannose-binding lectin deficiency with eosinophilic meningoencephalitis due to Angiostrongylus cantonensis in children: a case series
Bárbara Padilla-Docal, Alberto J Dorta-Contreras, Raisa Bu-Coifiu-Fanego, René H Martínez-Alderete, Olga de Paula-Almeida, Hansotto Reiber, Jens Jensenius
Journal of Medical Case Reports , 2011, DOI: 10.1186/1752-1947-5-330
Abstract: Three Caucasian boys (aged five-years-old, 10-years-old and six-years-old) with a diagnosis of eosinophilic meningoencephalitis caused by Angiostrongylus cantonensis were studied. Serum immunoglobulin A (IgA), IgM, IgG, and complements C3c and C4 levels were quantified by using an immunodiffusion technique. Immunoglobulin E in serum was quantified by nephelometry and mannose-binding lectin by time-resolved fluorometry. Mannose-binding lectin deficiency was observed in the three patients. The first patient showed a reduction in the levels of IgA and IgM and an increase in the values of IgE and C4. The second patient showed a reduction in mannose-binding lectin level with increased IgG, C4 and IgE levels, and the third patient showed a decrease in mannose-binding lectin level and increased levels of IgM and complement C3c as well as a low level of C4.To the best of our knowledge, this is the first report of mannose-binding lectin deficiency associated with Angiostrongylus cantonensis meningoencephalitis in children, and it may contribute to the understanding of the participation of this component of the lectin pathway in the development of the disease.Eosinophilic meningitis, a potentially fatal disease caused by Angiostrongylus cantonensis, a parasitic nematode, is considered an emerging infectious disease [1]. Adult A. cantonensis live in the pulmonary arteries of its definitive hosts, that is, rodents, especially rats, which pass infective first-stage larvae (L1) in their feces. The life cycle also involves mollusks harboring larval stages. In humans, larvae fail to mature, and hence humans and their excreta play no role in the transmission and direct dissemination of the parasite. Humans become infected by ingesting third-stage larvae (L3) in raw or undercooked intermediate host mollusks (for example, snails and slugs) or paratenic hosts (for example, freshwater prawns, crabs, frogs and fish) [1]. Lettuce and vegetable juice have also been identified as sources of
Phylogenetic relationship of the Brazilian isolates of the rat lungworm Angiostrongylus cantonensis (Nematoda: Metastrongylidae) employing mitochondrial COI gene sequence data  [cached]
Monte Tainá CC,Sim?es Raquel O,Oliveira Ana Paula M,Novaes Clodoaldo F
Parasites & Vectors , 2012, DOI: 10.1186/1756-3305-5-248
Abstract: Background The rat lungworm Angiostrongylus cantonensis can cause eosinophilic meningoencephalitis in humans. This nematode’s main definitive hosts are rodents and its intermediate hosts are snails. This parasite was first described in China and currently is dispersed across several Pacific islands, Asia, Australia, Africa, some Caribbean islands and most recently in the Americas. Here, we report the genetic variability among A. cantonensis isolates from different geographical locations in Brazil using mitochondrial cytochrome c oxidase subunit I (COI) gene sequences. Methods The isolates of A. cantonensis were obtained from distinct geographical locations of Brazil. Genomic DNAs were extracted, amplified by polymerase reaction, purified and sequenced. A partial sequence of COI gene was determined to assess their phylogenetic relationship. Results The sequences of A. cantonensis were monophyletic. We identified a distinct clade that included all isolates of A. cantonensis from Brazil and Asia based on eight distinct haplotypes (ac1, ac2, ac3, ac4, ac5, ac6, ac7 and ac8) from a previous study. Interestingly, the Brazilian haplotype ac5 is clustered with isolates from Japan, and the Brazilian haplotype ac8 from Rio de Janeiro, S o Paulo, Pará and Pernambuco states formed a distinct clade. There is a divergent Brazilian haplotype, which we named ac9, closely related to Chinese haplotype ac6 and Japanese haplotype ac7. Conclusion The genetic variation observed among Brazilian isolates supports the hypothesis that the appearance of A. cantonensis in Brazil is likely a result of multiple introductions of parasite-carrying rats, transported on ships due to active commerce with Africa and Asia during the European colonization period. The rapid spread of the intermediate host, Achatina fulica, also seems to have contributed to the dispersion of this parasite and the infection of the definitive host in different Brazilian regions.
Development-Specific Differences in the Proteomics of Angiostrongylus cantonensis  [PDF]
Hui-Cong Huang, Li-Li Yao, Zeng-Mei Song, Xing-Pan Li, Qian-Qian Hua, Qiang Li, Chang-Wang Pan, Chao-Ming Xia
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0076982
Abstract: Angiostrongyliasis is an emerging communicable disease. Several different hosts are required to complete the life cycle of Angiostrongylus cantonensis. However, we lack a complete understanding of variability of proteins across different developmental stages and their contribution to parasite survival and progression. In this study, we extracted soluble proteins from various stages of the A. cantonensis life cycle [female adults, male adults, the fifth-stage female larvae (FL5), the fifth-stage male larvae (ML5) and third-stage larvae (L3)], separated those proteins using two-dimensional difference gel electrophoresis (2D-DIGE) at pH 4–7, and analyzed the gel images using DeCyder 7.0 software. This proteomic analysis produced a total of 183 different dominant protein spots. Thirty-seven protein spots were found to have high confidence scores (>95%) by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Comparative proteomic analyses revealed that 29 spots represented cytoskeleton-associated proteins and functional proteins. Eight spots were unnamed proteins. Twelve protein spots that were matched to the EST of different-stage larvae of A. cantonensis were identified. Two genes and the internal control 18s were chosen for quantitative real-time PCR (qPCR) and the qPCR results were consistent with those of the DIGE studies. These findings will provide a new basis for understanding the characteristics of growth and development of A. cantonensis and the host–parasite relationship. They may also assist searches for candidate proteins suitable for use in diagnostic assays and as drug targets for the control of eosinophilic meningitis caused by A. cantonensis.
Aporte de Cuba al estudio de Angiostrongylus cantonensis Contribution of Cuba to the study of Angiostrongylus cantonensis  [cached]
Alberto J Dorta Contreras
ACIMED , 2007,
Abstract: El primer informe en el hemisferio occidental sobre el Angiostrongylus cantonensis, causante de la meningoencefalitis eosinofílica, se realizó en Cuba en 1981. A lo largo de 25 a os, muchos investigadores cubanos han estudiado, tanto al parásito, como la enfermedad que produce en el hombre. Con el objetivo de analizar el impacto científico de estos aportes, se revisaron las bases de datos Medline (PubMed), ScieELO, Revistas Médicas Cubanas, Web of Science, Scopus, Google Scholar y WOSCU. Los 37 artículos identificados constituyen una prueba del aporte de nuestros investigadores al conocimiento universal de esta parasitosis emergente en nuestro hemisferio. The first report in the Western Hemisphere of Angiostrongylus cantonensis, which causes eosinophilic meningoencephalitis, was made in Cuba, in 1981. For 25 years, several Cuban researchers have studied the parasite and the disease it produces in human beings. In order to analyse the scientific impact of these contributions, Medline (PubMed), ScieELO, Revistas Médicas Cubanas, Web of Science, Scopus, Google Scholar y WOSCU databases, were reviewed. The 37 papers found are a proof of the contributions or our researchers to the universal knowledge of this emerging parasitosis in our hemisphere.
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