Molecular differentiation of Angiostrongylus costaricensis, A. cantonensis, and A. vasorum by polymerase chain reaction- restriction fragment length polymorphism

Insights into the genetic diversity of Angiostrongylus spp. causing human angiostrongyliasis and implications for molecular identification and diagnosis

Angiostrongylus cantonensis and Angiostrongylus costaricensis are known human pathogens responsible for eosinophilic angiostrongyliasis and abdominal angiostrongyliasis, respectively. Humans are accidental hosts, where infection occurs through the consumption of the infective larva stage 3 in intermediate or paratenic hosts. The proven method for abdominal angiostrongyliasis diagnosis is the histological examination through tissue biopsy, while the diagnosis of eosinophilic angiostrongyliasis is the detection of larva in the cerebrospinal fluid. As there is molecular evidence of cryptic species within A. cantonensis and A. costaricensis lineages, along with morphological similarities within both lineages, accurate species identification and disease diagnosis may be challenging. Moreover, species within the lineages share similar intermediate and definitive hosts and geographic distribution. For example, both A. cantonensis and Angiostrongylus malaysiensis (a closely related species in A. cantonensis lineage) overlap in their geographic distribution in Southeast Asia. Additionally, variations in the molecular makeup of A. costaricensis and A. cantonensis lineages may impact the pathogenicity, infectivity, and disease severity of angiostrongyliasis. Understanding of the genetic diversity of both lineages is a cornerstone for improved diagnosis and disease intervention, especially in a changing global environment. To shed light and provide insights into the genetic diversity of the Angiostrongylus lineages causing human angiostrongyliasis, we aim to present an up-to-date review of the studies conducted and genetic markers used for A. costaricensis and A. cantonensis lineages. The implications for accurate molecular identification and diagnosis of human angiostrongyliasis are also discussed.

A Taq-Man-based multiplex quantitative PCR for the simultaneous detection and quantification of Angiostrongylus vasorum, Crenosoma vulpis, and species of respiratory capillarids in canids

In recent years, Angiostrongylus vasorum, Crenosoma vulpis, Eucoleus aerophilus (syn. Capillaria aerophila) and Eucoleus boehmi (syn. Capillaria boehmi), commonly referred to as canine lungworms, have gained a growing interest worldwide as the result of their geographical expansion. Each of these nematode species differs considerably in its biology and pathogenicity. Despite their impact on dogs' health, these parasites are often underdiagnosed owing to diagnostic challenges. Here, we describe the development and validation of a Taq-Man-based multiplex quantitative PCR (qPCR) for the simultaneous detection of the main species of canine lungworms in faeces of infected dogs. Using 10-fold serial dilutions of synthetic gene block fragments containing individual sequence targets of each lungworm species, the analytical sensitivity of the assay ascertained was 1.84 ng/μl for A. vasorum, 3.08 ng/μl for C. vulpis and 0.79 ng/μl for Eucoleus spp. The sensitivity of the assays and their ability to detect mixed species infections were compared with microscopy-based techniques (faecal floatation and Baermann technique) applied to faecal samples submitted for lungworm testing through an accredited diagnostic laboratory at the Institute of Parasitology, University of Zurich, Switzerland, and from community dogs as part of a research project on canine endoparasites in Cambodia. The multiplex qPCR displayed high diagnostic sensitivity (42/46, 91.3%; 95% Confidence Interval (CI): 79.1-97.1%) and a diagnostic specificity of 100% (45/45, 95% CI: 90.6-100%), and was able to detect 42.9% additional mixed lungworm species infections compared with microscopy-based methods. Kappa statistics showed substantial agreement between the qPCRs and microscopy for mixed infections (κ = 0.72, 95% CI: 0.4-1) and Eucoleus spp. (κ = 0.65, 95% CI: 0.45-0.85) and almost perfect agreement for C. vulpis (κ = 0.85, 95% CI: 0.63-1) and A. vasorum (κ = 0.92, 95% CI: 0.84-1). This multiplex qPCR enables timely, accurate, and sensitive diagnosis of canine lungworm species in faecal samples and can be used to monitor the geographical distribution and emergence of these parasitic species, globally.

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.

In the Dawn of an Early Invasion: No Genetic Diversity of Angiostrongylus cantonensis in Ecuador?

The nematode Angiostrongylus cantonensis has been reported worldwide. However, some basic questions remain unanswered about A. cantonensis in Ecuador: (1) Was the invasion of A. cantonensis in Ecuador unique, or did it occur in different waves? (2) Was this invasion as recent as historical records suggest? (3) Did this invasion come from other regions of South America or elsewhere? To address these issues, we assessed the genetic diversity of MT-CO1 gene sequences from isolates obtained in 11 of Ecuador's 24 provinces. Our Bayesian inference phylogenetic tree recovered A. cantonensis as a well-supported monophyletic group. All 11 sequences from Ecuador were identical and identified as AC17a. The haplotype AC17a, found in Ecuador and the USA, formed a cluster with AC17b (USA), AC13 (Thailand), and AC12a-b (Cambodia). Notably, all the samples obtained in Ecuadorian provinces' different geographic and climatic regions had no genetic difference. Despite the lack of genetic information on A. cantonensis in Latin America, except in Brazil, our finding differs from previous studies by its absence of gene diversity in Ecuador. We concluded that the invasion of A. cantonensis in Ecuador may have occurred: (1) as a one-time event, (2) recently, and (3) from Asia via the USA. Further research should include samples from countries neighboring Ecuador to delve deeper into this.

Abdominal angiostrongyliasis in the Americas: fifty years since the discovery of a new metastrongylid species, Angiostrongylus costaricensis

Angiostrongylus costaricensis is a zoonotic parasitic nematode described for the first time in 1971 by Pedro Morera and Rodolfo Céspedes in Costa Rica. This parasite causes an infection known as abdominal angiostrongyliasis, affecting mainly school-aged children and young adults. Infection with A. costaricensis has been associated with a myriad of rodent and mollusk species in the Americas and the Caribbean, as its natural hosts and reservoirs. In this commemorative review, we highlight the extensive research collected through a 50-year journey, which includes ecological, pathological, and molecular studies on A. costaricensis and its implicated disease. We also identify major knowledge gaps in its evolutionary history, the ecological role of imported and invasive mollusk species, and immune response. We propose that the advent of -omics analyses will allow us to gather novel information regarding A. costaricensis biology and infection dynamics, as well as to promote the design of much-needed sensitive and specific diagnostic tools.

Genetic Characterization and Detection of Angiostrongylus cantonensis by Molecular Approaches

Angiostrongylus cantonensis constitutes a major etiologic agent of eosinophilic meningoencephalitis. The detection methods for angiostrongyliasis mainly depend on morphology or immunology. A firmer diagnosis could be reached by directly detecting the parasite in the cerebrospinal fluid or through laboratory assays that are specific for Angiostrongylus-induced antibodies or the parasite's DNA. A. cantonensis detection could be carried out by larva release from the tissue upon pepsin digestion. However, the procedure requires live mollusks, which might complicate the analysis of large amounts of samples. Since morphological assays are limited, multiple molecular techniques have been put forward for detecting A. cantonensis, including PCR amplification of targets followed by fragment length or DNA sequence analysis. This allows rapid and accurate identification of A. cantonensis for efficient infection management and epidemiological purposes. In this study, we reviewed the current methods, concepts, and applications of molecular approaches to better understand the genetic characterization, molecular detection methods, and practical application of molecular detection in A. cantonensis.

Angiostrongylus cantonensis in urban populations of terrestrial gastropods and rats in an impoverished region of Brazil

The nematode Angiostrongylus cantonensis is the most common cause of neuroangiostrongyliasis (manifested as eosinophilic meningitis) in humans. Gastropod molluscs are used as intermediate hosts and rats of various species are definitive hosts of this parasite. In this study, we identified several environmental factors associated with the presence and abundance of terrestrial gastropods in an impoverished urban region in Brazil. We also found that body condition, age and presence of co-infection with other parasite species in urban Rattus norvegicus, as well as environmental factors were associated with the probability and intensity of A. cantonensis infection. The study area was also found to have a moderate prevalence of the nematode in rodents (33% of 168 individuals). Eight species of molluscs (577 individuals) were identified, four of which were positive for A. cantonensis. Our study indicates that the environmental conditions of poor urban areas (presence of running and standing water, sewage, humidity and accumulated rain and accumulation of construction materials) influenced both the distribution and abundance of terrestrial gastropods, as well as infected rats, contributing to the maintenance of the A. cantonensis transmission cycle in the area. Besides neuroangiostrongyliasis, the presence of these hosts may also contribute to susceptibility to other zoonoses.

First record of natural infection by Angiostrongylus cantonensis (Nematoda: Metastrongyloidea) in Belocaulus willibaldoi and Rattus norvegicus in an urban area of São Paulo city, SP, Brazil

Angiostrongylus cantonensis, a rat lungworm, is one of the leading causes of eosinophilic meningitis in humans. Infection in humans occurs by the ingestion of intermediate hosts, undercooked paratenic hosts or contaminated vegetables and fruits by mucus from infected molluscs. This zoonosis is widespread in tropical and subtropical areas of Southeast Asia, it has also been reported in the Pacific Islands as well as in other regions of Americas. In Brazil, human cases of angiostrongyliasis have been reported since 2007 in Southeast, Northeast, and South regions. In January 2011, we collected a batch of 30 Belocaulus willibaldoi slides in a neighborhood of São Paulo city (Parque Fernanda). Six of them were used for identifying species, and the others (24) were used in parasitological tests through digestion in peptic solution and then larvae isolation by the Rugai method. A total of 250 larvae were obtained and they had morphological traits of Angiostrongylus spp. Later, four Golden hamsters (Mesocricetus auratus) were infected with 38 larvae that allowed the recovery of young worms from the brain and lungs of rodents on the 21st and 30th day of infection. In this same neighborhood we captured rodents (Rattus norvegicus) that, after necropsy led us to recovery of 22 adult worms in the pulmonary arteries (14 males and 8 females) in May 2011. The larvae and worms obtained from natural infection were evaluated by morphological and morphometric parameters, as well as biological behavior patterns and molecular profile. All methodologies identified the parasite as Angiostrongylus cantonensis. In this way, we report for the first time, the natural infection by A. cantonensis in intermediate (B. willibaldoi) and definitive (R. norvegicus) hosts in a new urban region of Brazil.

Identification of cross-reactive markers to strengthen the development of immunodiagnostic methods for angiostrongyliasis and other parasitic infections

Angiostrongylus cantonensis is the main causative agent of eosinophilic meningoencephalitis (EoM) in humans. Molecular diagnostic methods are essential since the identification of larvae in cerebrospinal fluid (CSF) is extremely rare. To date, the detection of a 31 kDa antigen by Western blotting has been the primary immunodiagnostic method for EoM caused by A. cantonensis. However, cross-reactivity with other parasites has been observed. Therefore, we conducted a comparative analysis using sera from individuals with angiostrongyliasis. We also characterized proteins isolated from different cellular sources of A. cantonensis, Toxocara canis, Schistosoma mansoni, and Strongyloides stercoralis with mass spectrometry. A total of 115 cross-reactive proteins were identified. Three of these proteins, heat shock protein, an intermediate filament protein, and galectin 1, represent potential markers for cross-reactivity. In addition, synthetic peptides were generated from previously identified diagnostic targets and tested against sera from individuals infected with several other parasites. As a result, two other markers of cross-reactivity were identified: peptide #4 derived from the 14-3-3 protein and peptide #12 derived from the Lec-5 protein. In contrast, 34 proteins were exclusively present in the Angiostrongylus extracts and represent promising diagnostic molecules for specific identification of A. cantonensis infection. In particular, cytochrome oxidase subunit I is of great interest as a possible immunodiagnostic target for angiostrongyliasis.

Achatina fulica (Gastropoda: Pulmonata): Occurrence, environmental aspects and presence of nematodes in Sergipe, Brazil

Abstract The objective of this study was to identify the occurrence of Achatina fulica in the Great Aracaju-SE Territory. This research was developed during the months of June 2016 to May 2017. The plots methodology was used for the monthly collections, following the collection time of 20 minutes per area. The mollusks were measured and soon afterwards the parasitological analysis of the mucus and faeces was performed. Molecular identification was performed to evaluate the possible presence of Angiostrongylus sp. We observed that the occurrence of A. fulica was more representative in urban areas, especially in vacant lots with the presence of litter and decomposing materials. In the specimens of A. fulica examined were male and female nematodes of the genus Rhabditis, in the research municipalities, except in Barra dos Coqueiros. No parasites of the genus Angiostrongylus were found in the mollusks examined. The influence of the presence of litter on the plots associated with the frequency of A. fulica was statistically significant. There was a correlation between the influence of rainfall and the frequency of A. fulica. A significant relationship between moisture and frequency and nematode positivity was identified. It was also observed that the larger the mollusk, the greater the chances of being infected by nematodes. Scientific knowledge about the biology of the A. fulica species associated with human intervention such as the maintenance of land and adequate sanitary measures may be important factors for a better control of this invasive mollusk.

Angiostrongylus vasorum and Aelurostrongylus abstrusus: Neglected and underestimated parasites in South America

The gastropod-borne nematodes Angiostrongylus vasorum and Aelurostrongylus abstrusus are global causes of cardio/pulmonary diseases in dogs and cats. In the last decade, the number of reports on canine and feline lungworms has increased in several areas of Europe and North America. The unspecific clinical signs and prolonged course of these diseases often renders diagnosis challenging. Both infections are considered as emerging and underestimated causes of disease in domestic pets. In South America, little information is available on these diseases, apart from occasional reports proving the principle presence of A. vasorum and A. abstrusus. Thus, the purpose of this review is to summarize reports on infections in both domestic and wildlife animals in South America and to increase the awareness on gastropod-borne metastrongyloid parasites, which also include important zoonotic species, such as A. cantonensis and A. costaricensis. This review highlights the usefulness of diagnostic tools, such as the Baermann funnel technique, serology and PCR, and proposes to include these routinely on cases with clinical suspicion for lungworm infections. Future national epidemiological surveys are recommended to be conducted to gain a deeper insight into the actual epidemiological situation of gastropod-borne parasitoses in South America.

[Standardization of a multiplex real-time PCR test for the identification of Angiostrongylus cantonensis, A. costaricensis and A. vasorum]

INTRODUCTION

Angiostrongyliasis is a disease caused by Angiostrongylus nematodes that is present worldwide. The infections with the highest impact on human and animal health are caused by A. cantonensis, A. costaricensis, and A. vasorum. Clinical forms of the disease in humans are eosinophilic meningitis and abdominal angiostrongyliasis, while the most common effect on dogs are cardiopulmonary damages. It is deemed as an emerging disease as the result of the global dissemination of the African snail Lissachatina fulica, an intermediary host of these parasites. The few diagnostic methods for Angiostrongylus spp. are unspecific, costly, and not very sensitive. It is urgent to develop a sensitive, specific and accessible diagnostic tool for the control of human and animal angiostrongyliasis.

OBJECTIVE

To develop a qPCR multiple test to identify the three pathogenic species of Angiostrongylus.

MATERIALS AND METHODS

Through a bio-informatic analysis, we selected a sequence of the ITS-2 region of the Angiostrongylus genome to guarantee the specificity of primers and probes. We extracted DNA from adult parasites as positive control, and from larvae using the DNeasy Blood&Tissue® kit. Quantitative PCR reactions were conducted on a Smartcycler Cepheid® thermocycler using a master mix QuantiTect® kit. DNA from human beings, other parasites and the African snail was used as negative control.

RESULTS

The threshold cycle values for positive DNA controls were: 21 for Angiostrongylus cantonensis, 22 for A. costaricensis, and 31 for A. vasorum. In negative controls, the threshold cycle was zero. qPCR showed an amplification efficiency of 2 (100%).

CONCLUSIONS

A multiple qPCR was standardized at the laboratory for three clinically significant species of Angiostrongylus.

Troglostrongylus brevior: a new parasite for Romania

Background

The genus Troglostrongylus includes nematodes infecting domestic and wild felids. Troglostrongylus brevior was described six decades ago in Palestine and subsequently reported in some European countries (Italy, Spain, Greece, Bulgaria, and Bosnia and Herzegovina). As the diagnosis by the first-stage larvae (L1) may be challenging, there is a possibility of confusion with Aelurostrongylus abstrusus. Hence, the knowledge on the distribution of this neglected feline parasite is still scarce. The present paper reports the first case of T. brevior infection in Romania. In July 2017, a road-killed juvenile male Felis silvestris, was found in in Covasna County, Romania. A full necropsy was performed and the nematodes were collected from the trachea and bronchioles. Parasites were sexed and identified to species level, based on morphometrical features. A classical Baermann method was performed on the lungs and the faeces to collect the metastrongyloid larvae. Genomic DNA was extracted from an adult female nematode. Molecular identification was accomplished with a PCR assay targeting the ITS2 of the rRNA gene.

Results

Two males and one female nematodes were found in the trachea and bronchioles. They were morphologically and molecularly identified as T. brevior. The first-stage larvae (L1) recovered from the lung tissue and faeces were morphologically consistent with those of T. brevior. No other pulmonary nematodes were identified and no gross pulmonary lesions were observed.

Conclusions

This paper represents the first report of Troglostrongylus brevior infection in Romania, so far representing the second northernmost location for this genus in Europe. The diversity of species infecting wild and domestic felids and the differences regarding the clinical significance of these nematodes highlight the need for a more intense surveillance and proper diagnosis of feline lungworm infections, especially in countries where more species were demonstrated to be present. Furthermore, an increased awareness between clinicians is needed for a correct diagnostic approach to feline lungworm diagnosis.

The genetic variation of Angiostrongylus cantonensis in the People's Republic of China

Background

The People’s Republic of China (P.R. China) is the presumptive home range of the rat lungworm Angiostrongylus cantonensis, a major aetiological agent of human eosinophilic meningitis. We present a study of the genetic variation of A. cantonensis in P.R. China. Our aim was to deepen the current knowledge pertaining to its origin and global spread from a molecular perspective.

Methods

Adult A. cantonensis were collected in the frame of a national survey and identified based on morphological criteria. Polymerase chain reaction (PCR) was employed to amplify the target DNA sequences (cytochrome c oxidase subunit I (cox1), nicotinamide adenine dinucleotide dehydrogenase subunit 1 (nad1) and internal transcribed spacer (ITS)). The PCR product of cox1 was directly submitted to sequencing, while clone sequencing was used for nad1 and ITS. The identity of the samples was verified by comparing the sequences to those of accepted A. cantonensis specimens. The specific composition of substitutions in each gene was analysed, and the genotypes were compared based on the complete cox1, nad1 and ITS genes.

Results

We characterised the complete mitochondrial genes cox1 and nad1 of 130 specimens and obtained 357 nuclear sequences containing two complete ITS (ITS1 and ITS2) and 5.8S rRNA of the same samples. All specimens were genetically confirmed as A. cantonensis. Two major groups (i.e. I and II) were identified according to the phylogeny of cox1 sequences. Group I could be further categorised into six distinct clades. Almost half of the specimens (47.7%) belong to the clade Ia and 22.3% to the group II. The former was widely distributed across the study region. A variable number of repeat units in three microsatellites was observed, resulting in considerable length variation in ITS. Intragenomic variation of ITS sequences was found in a large proportion of the samples. Genotyping showed a striking difference between mitochondrial DNA and ITS.

Conclusions

Our results demonstrate that A. cantonensis is the only rat lungworm species in P.R. China and shows high genetic diversity. Results of diversity and genotyping of A. cantonensis can be impacted by the sequencing strategy and biomarker. Although ITS may be a valuable marker for interspecific identification, it is not suitable for studying the intraspecific variation of A. cantonensis due to its high intragenomic variation and current challenges for direct sequencing.

Electronic supplementary material

The online version of this article (doi:10.1186/s40249-017-0341-z) contains supplementary material, which is available to authorized users.

Phylogeography of Angiostrongylus cantonensis (Nematoda: Angiostrongylidae) in southern China and some surrounding areas

Angiostrongylus cantonensis is of increasing public health importance as the main zoonotic pathogen causing eosinophilic meningitis or meningoencephalitis, which has been documented all over the world. However, there are very limited studies about its phylogeography and spread pattern. In the present study, the phylogeography of A. cantonensis in southern China (including Taiwan) and partial areas of Southeast Asia were studied based on the sequences of complete mitochondrial cytochrome b (Cytb) gene. A total of 520 individuals of A. cantonensis obtained from 13 localities were sequenced for the analyses and grouped into 42 defined haplotypes. The phylogenetic tree (NJ tree and BI tree) revealed a characteristic distribution pattern of the four main lineages, with detectable geographic structure. Genetic differentiation among populations was significant, but demographic expansion could not be detected by either neutrality tests or mismatch distribution analysis, which implied a low gene flow among the local populations in different regions where the samples were collected. Two unique lineages of the A. cantonensis population in Taiwan were detected, which suggests its multiple origin in the island. Populations in Hekou (China) and Laos showed the highest genetic diversities, which were supported by both genetic diversity indices and AMOVA. These results together infer that the area around Thailand or Hekou in Yunnan province, China are the most likely origins of Angiostrongylus cantonensis.

Since it was described in 1935, more than 2800 cases of the disease have reportedly been caused by A. cantonensis worldwide, primarily in tropical and subtropical regions. Despite a relevant body of research on pathology, diagnosis and treatment, little is known about the phylogeography of A. cantonensis. Since southern China is one of the endemic regions, we performed this experiment to reveal the distribution pattern of A. cantonensis in southern China based on mitochondrial Cytb data. Our results revealed a unique pattern probably shaped by the biological features of its hosts and geographical barriers, simultaneously reflecting a low gene flow among populations. Nevertheless, the connective consanguinity between some locations (Taiwan and Southeast Asia) provides new evidence of the impact on its dispersal as influenced by human activities, indicating the emerging need of an effective strategy to control this helminth. In addition to the corresponding investigation on its hosts, more attention to the situation in southwest China and Southeast Asia is suggested to facilitate the understanding of the phylogeography of A. cantonensis.

Angiostrongylus vasorum in Romania: an extensive survey in red foxes, Vulpes vulpes

Background

Angiostrongylus vasorum is the causative agent of canine angiostrongylosis, a severe snail-borne disease of dogs. Red foxes are important natural reservoirs of infection, and surveys of foxes provide a more objective picture of the parasite distribution. Our aim was to investigate the possibility of the presence of A. vasorum in red foxes from the western part of Romania and to analyse the risk factors related to the sex, age and geographic origin of the foxes. Between July 2016 and April 2017, 567 hunted red foxes from 10 counties of western Romania were examined by necropsy for the presence of lungworms.

Results

Overall, the infection with A. vasorum has been found in 24 red foxes (4.2%) originating in four counties (Mureș, Hunedoara, Sălaj and Cluj). There was no significant difference between the prevalence in males and females, between juveniles and adults and between counties.

Conclusions

This is the first report of autochthonous infections of A. vasorum in Romania, showing a relatively low prevalence and extending eastwards the known distributional range of this parasite in Europe. The presence of autochthonous cases in domestic dogs in Romania remains to be confirmed by further studies.

Prevalence and distribution of Angiostrongylus cantonensis (Nematoda, Angiostrongylidae) in Achatina fulica (Mollusca, Gastropoda) in Baixada Santista, São Paulo, Brazil

INTRODUCTION

Angiostrongylus cantonensis is causes eosinophilic meningoencephalitis in humans. Worldwide expansion of this nematode is linked to the dispersion of their hosts. This study aimed to determine the prevalence of A. cantonensis infection in Achatina fulica in the nine municipalities that make up Baixada Santista, São Paulo, Brazil.

METHODS

Angiostrongylus cantonensis larvae were analyzed using optical microscopy. We performed polymerase chain reaction and restriction fragment length polymorphism using restriction endonuclease ClaI, directed to the internal transcribed spacer region 2 of A. cantonensis larval DNA.

RESULTS

Of the 540 snails analyzed, 117 (21.7%) were infected by A. cantonensis. For morphological and morphometric analyses, 60 larvae were used. Second-stage larvae were, on average, 358.2µm long and 26.4µm wide, while third-stage larvae were, on average, 450µm long and 21.12µm wide. The tails of the larvae ended in a fine tip.

CONCLUSIONS

All municipalities comprising Baixada Santista had A. fulica that were naturally infected with A. cantonensis. All of the observed characteristics were typical of the species.

Angiostrongylus cantonensis: a review of its distribution, molecular biology and clinical significance as a human pathogen

Angiostrongylus cantonensis is a metastrongyloid nematode found widely in the Asia-Pacific region, and the aetiological agent of angiostrongyliasis; a disease characterized by eosinophilic meningitis. Rattus rats are definitive hosts of A. cantonensis, while intermediate hosts include terrestrial and aquatic molluscs. Humans are dead-end hosts that usually become infected upon ingestion of infected molluscs. A presumptive diagnosis is often made based on clinical features, a history of mollusc consumption, eosinophilic pleocytosis in cerebral spinal fluid, and advanced imaging such as computed tomography. Serological tests are available for angiostrongyliasis, though many tests are still under development. While there is no treatment consensus, therapy often includes a combination of anthelmintics and corticosteroids. Angiostrongyliasis is relatively rare, but is often associated with morbidity and sometimes mortality. Recent reports suggest the parasites' range is increasing, leading to fatalities in regions previously considered Angiostrongylus-free, and sometimes, delayed diagnosis in newly invaded regions. Increased awareness of angiostrongyliasis would facilitate rapid diagnosis and improved clinical outcomes. This paper summarizes knowledge on the parasites' life cycle, clinical aspects and epidemiology. The molecular biology of Angiostrongylus spp. is also discussed. Attention is paid to the significance of angiostrongyliasis in Australia, given the recent severe cases reported from the Sydney region.

Angiostrongylus chabaudi (Biocca, 1957) in wildcat (Felis silvestris silvestris, S) from Romania

Angiostrongylus chabaudi is a rare cardio-pulmonary nematode infecting felids. Although almost 60 years have passed since the original description of the species in Italy, this parasite has been seldom found in domestic and wildcats in southern Europe. The present study aims to report a new case of patent A. chabaudi infection in a road-killed wildcat from Maramureș County in Northern Romania. The necropsy revealed the presence of parasites in the pulmonary arteries and the right ventricle, and the fecal examination showed the presence of L1 larvae. Parasites were morphologically and morphometrically characterized as A. chabaudi, showing 100 % nucleotide similarity to an Angiostrongylus sp. originating from a wildcat from Germany and 99 % to A. chabaudi from Italy. This study reports A. chabaudi for the first time in Eastern Europe, expanding knowledge about the distribution range of this species.

Eosinophilic meningitis caused by Angiostrongylus cantonensis: an emergent disease in Brazil

Eosinophilic meningitis (EoM) is an acute disease that affects the central nervous system. It is primarily caused by infection with the nematode Angiostrongylus cantonensis. This infection was previously restricted to certain Asian countries and the Pacific Islands, but it was first reported in Brazil in 2007. Since then, intermediate and definitive hosts infected with A. cantonensis have been identified within the urban areas of many states in Brazil, including those in the northern, northeastern, southeastern and southern regions. The goals of this review are to draw the attention of the medical community and health centres to the emergence of EoM in Brazil, to compile information about several aspects of the human infection and mode of transmission and to provide a short protocol of procedures for the diagnosis of this disease.

Molecular phylogeography of Angiostrongylus cantonensis (Nematoda: Angiostrongylidae) and genetic relationships with congeners using cytochrome b gene marker

Angiostrongylus cantonensis is an important emerging zoonotic parasite causing human eosinophilic meningitis (or meningoencephalitis) in many parts of the world. To-date there is only a single study using mitochondrial cytochrome b (CYTB) gene to determine its genetic structure in eight geographical localities in Thailand. The present study examined the molecular phylogeography of this rat lungworm and its phylogenetic relationship with congeners using CYTB gene marker. A total of 15 CYTB haplotypes was found in 37 sequences from 14 geographical localities (covering north, west, east, central and south regions) in Thailand. These CYTB haplotypes were distinct from those of A. cantonensis for China and Hawaii. In Thailand, some CYTB haplotypes appeared to be confined to specific geographical localities. The partial CYTB DNA nucleotide sequences separated unequivocally the A. cantonensis isolates of Thailand, China and Hawaii as well as the congeners Angiostrongylus malaysiensis, A. costaricensis and Angiostrongylus vasorum, with A. malaysiensis grouped with A. cantonensis and A. costaricensis grouped with A. vasorum. Likewise the congeners of Metastrongylus and Onchocerca genera could also be clearly differentiated. The present study added two new definitive hosts (Bandicota savilei and Rattus losea) and three new localities (Mae Hong Son in the north, Tak in the west, and Phang Nga in the south) for A. malaysiensis in Thailand, indicating its wide occurrence in the country. Three CYTB haplotypes were found in the Thailand samples of A. malaysiensis. In addition to differentiation of congeners, CYTB gene marker could be used for determining the genetic diversity of a given population/taxon.

Intermediate hosts of Protostrongylus pulmonalis (Frölich, 1802) and P. oryctolagi Baboš, 1955 under natural conditions in France

BACKGROUND

Protostrongylus oryctolagi and P. pulmonalis are causative agents of pulmonary protostrongyliasis in Lagomorphs in France. These nematodes need usually one intermediate host for its life cycle, a terrestrial snail. However, some studies, mainly in experimental conditions, have identified the species of snails acting as intermediate hosts.

METHODS

In total, 3315 terrestrial snails and 307 slugs were collected in the field in South-Eastern France and analyzed to detect the presence of parasites. Identification of nematode parasites and snails were performed according to morphological and molecular approaches (D2 domain of the 28S rDNA for parasites; 18S and ITS-1 rDNA, COI and 16S mtDNA for snails).

RESULTS

Eighteen snails were found positive for Protostrongylids larvae. Haplotypes of the larvae corresponding to sequences of P. oryctolagi and P. pulmonalis were detected. Morphological identification of molluscs based on shell characters revealed 4 different morphotypes, and molecular results confirm the membership of these gastropods to the Hygromiidae and revealed 4 different species: Candidula gigaxii, 2 species of Cernuella sp. and Xeropicta derbentina. All infested snails were collected in wine cultures.

CONCLUSION

This study displays the first description of intermediate hosts of P. oryctolagi and the first report of X. derbentina as natural intermediate host of P. pulmonalis.

Angiostrongylus chabaudi Biocca, 1957: a new parasite for domestic cats?

Background

Natural infection with a species of Angiostrongylus has been reported only once in wildcats from central Italy by Biocca in 1957. The causative species of this infection was identified as Angiostrongylus chabaudi. Following this report, this parasite had never been found in either wild or domestic cats.

Findings

The lungs and the pulmonary arteries of an adult female cat (Felis silvestris catus), road-killed in Sardinia, Italy, were macroscopically examined and dissected under a light microscope for the presence of parasites. A slender nematode was detected and its morphometrical features were consistent with those of A. chabaudi. Morphological data were supplemented by sequencing of the partial cytochrome oxidase c subunit 1 (cox1) gene, as well as the internal transcribed spacer 2 (ITS2) of the rDNA. Nucleotide sequences displayed 99% homology with the ITS2 sequence [GenBank KM216825.1] of a specimen of Angiostrongylus sp. recovered recently from the pulmonary artery of a wildcat in Germany and 91% with cox1 sequence [GenBank GU138118.1] of Angiostrongylus vasorum.

Conclusion

The results of the present study indicate, for the first time, that A. chabaudi may also infect domestic cats, and thus should be considered in the diagnosis of metastrongyloid species infecting their cardio-pulmonary system.

Canine angiostrongylosis: recent advances in diagnosis, prevention, and treatment

Angiostrongylus vasorum is a parasitic nematode affecting the heart and pulmonary arteries of wild (eg, foxes) and domestic canids. The parasite has an indirect life cycle in which slugs and snails act as intermediate hosts. In the last few years the parasite has spread outside the traditional endemic foci, and there is a rise of documented cases of canine angiostrongylosis across Europe. Angiostrongylus vasorum causes cardiopulmonary disorders and coagulopathies, along with different nonspecific clinical signs. Fatal infections are frequently reported. Given the severity of the infection and the recent geographic spreading of the parasite, this article reviews and discusses the current knowledge of A. vasorum, with a special focus on recent insights on diagnosis, prevention, and treatment of dog angiostrongylosis.

Reliable molecular identification of nine tropical whitefly species

The identification of whitefly species in adult stage is problematic. Morphological differentiation of pupae is one of the better methods for determining identity of species, but it may vary depending on the host plant on which they develop which can lead to misidentifications and erroneous naming of new species. Polymerase chain reaction (PCR) fragment amplified from the mitochondrial cytochrome oxidase I (COI) gene is often used for mitochondrial haplotype identification that can be associated with specific species. Our objective was to compare morphometric traits against DNA barcode sequences to develop and implement a diagnostic molecular kit based on a RFLP-PCR method using the COI gene for the rapid identification of whiteflies. This study will allow for the rapid diagnosis of the diverse community of whiteflies attacking plants of economic interest in Colombia. It also provides access to the COI sequence that can be used to develop predator conservation techniques by establishing which predators have a trophic linkage with the focal whitefly pest species.

Fatal Parastrongylus dujardini Infection in Captive Callitrichids

Intravascular nematodes were considered the cause of death of 14 captive callitrichids. All animals were captive born at zoos in France and died with little or no premonitory signs of disease. No consistent gross lesions were observed at necropsy, although in certain cases intracardiac adult parasites were noted. The most significant histologic findings were verminous pneumonia and pulmonary endarteritis. In all cases except one, intravascular adult nematodes were observed with eggs and larvae in the lungs. Adult nematodes were obtained from 8 animals and in all cases were identified as Parastrongylus dujardini. To the authors’ knowledge, this is the first report of intravascular angiostrongylosis with primary cardiopulmonary location in callitrichids in France.

Angiostrongylus cantonensis (Nematode: Metastrongyloidea) in molluscs from harbour areas in Brazil

Angiostrongylus cantonensis is the most common aetiological agent of human eosinophilic meningoencephalitis. Following a report indicating the presence of this parasite in Brazil in 2007, the present study was undertaken to investigate the presence of A. cantonensis in the surrounding Brazilian port areas. In total, 30 ports were investigated and the following molluscs were identified: Achatina fulica, Belocaulus sp., Bradybaena similaris sp., Cyclodontina sp., Helix sp., Leptinaria sp., Melampus sp., Melanoides tuberculata, Phyllocaulis sp., Pomacea sp., Pseudoxychona sp., Rhinus sp., Sarasinula marginata, Streptaxis sp., Subulina octona, Succinea sp., Tomigerus sp., Wayampia sp. and specimens belonging to Limacidae and Orthalicinae. Digestion and sedimentation processes were performed and the sediments were examined. DNA was extracted from the obtained larvae and the internal transcribed spacer region 2 was analysed by polymerase chain reaction-restriction fragment length polymorphism after digestion with the endonuclease ClaI. Of the 30 ports investigated in this study, 11 contained molluscs infected with A. cantonensis larvae. The set of infected species consisted of S. octona, S. marginata, A. fulica and B. similaris. A total of 36.6% of the investigated ports were positive for A. cantonensis, indicating a wide distribution of this worm. It remains uncertain when and how A. cantonensis was introduced into South America.

Development and validation of real-time PCR for rapid detection of Mecistocirrus digitatus

Hematophagous activity of Mecistocirrus digitatus, which causes substantial blood and weight loss in large ruminants, is an emerging challenge due to the economic loss it brings to the livestock industry. Infected animals are treated with anthelmintic drugs, based on the identification of helminth species and the severity of infection; however, traditional methods such as microscopic identification and the counting of eggs for diagnosis and determination of level of infection are laborious, cumbersome and unreliable. To facilitate the detection of this parasite, a SYBR green-based real-time PCR was standardized and validated for the detection of M. digitatus infection in cattle and buffaloes. Oligonucleotides were designed to amplify partial Internal Transcribed Spacer (ITS)-1 sequence of M. digitatus. The specificity of the primers was confirmed by non-amplification of DNA extracted from other commonly occurring gastrointestinal nematodes in ruminants. Plasmids were ligated with partial ITS-1 sequence of M. digitatus, serially diluted (hundred fold) and used as standards in the real-time PCR assay. The quantification cycle (Cq) values were plotted against the standard DNA concentration to produce a standard curve. The assay was sensitive enough to detect one plasmid containing the M. digitatus DNA. Clinical application of this assay was validated by testing the DNA extracted from the faeces of naturally infected cattle (n = 40) and buffaloes (n = 25). The results were compared with our standard curve to calculate the quantity of M. digitatus in each faecal sample. The Cq value of the assay depicted a strong linear relationship with faecal DNA content, with a regression coefficient of 0.984 and efficiency of 99%. This assay has noteworthy advantages over the conventional methods of diagnosis because it is more specific, sensitive and reliable.

Comprehensive proteomic profiling of adult Angiostrongylus costaricensis, a human parasitic nematode

Angiostrongylus costaricensis is a nematode helminth that causes an intestinal acute inflammatory process known as abdominal angiostrongyliasis, which is a poorly understood human disease occurring in Latin America. Our aim was to study the proteomic profiles of adult parasites focusing on immunogenic proteins. Total cellular extracts from both genders showed similar 2-DE profiles, with 60% of all protein spots focused between pH 5-7 and presenting molecular masses from 20.1 to 66 kDa. A total of 53 different dominant proteins were identified in our dataset and were mainly associated with the following over-represented Gene Ontology Biological Process terms: "macromolecule metabolic process", "developmental process", "response to stress", and "biological regulation". Female and male immunoblots showed similar patterns of reactive proteins. Immunoreactive spots identified by MALDI-PSD were found to represent heat shock proteins, a putative abnormal DAuer Formation family member, and galectins. To date, very few biochemical analyses have focused on the nematode Angiostrongylus costaricensis. As such, our results contribute to a better understanding of its biology and the mechanisms underlying the host-parasite relationship associated with this species. Moreover, our findings represent a first step in the search for candidate proteins for diagnostic assays and the treatment of this parasitic infection.

Molecular differentiation of Angiostrongylus taxa (Nematoda: Angiostrongylidae) by cytochrome c oxidase subunit I (COI) gene sequences

Nematodes of the genus Angiostrongylus are parasites of rodents and carnivores. They reside in the pulmonary or mesenteric arteries of their hosts. Two species are pathogenic in humans -Angiostrongylus cantonensis causes eosinophilic meningitis or meningoencephalitis, and Angiostrongylus costaricensis produces abdominal angiostrongyliasis. In addition Angiostrongylus malaysiensis may have the potential of being pathogenic in humans. The mitochondrial gene cytochrome c oxidase subunit I (COI) of these Angiostrongylus species and three geographical isolates (China, Hawaii and Thailand) of A. cantonensis were studied by polymerase chain reaction amplification and DNA sequencing. COI sequences of A. cantonensis, A. costaricensis and Angiostrongylus vasorum in the GenBank were included for comparison. Phylogenetic analysis by maximum-likelihood (ML), maximum-parsimony (MP), neighbour-joining (NJ) and Bayesian inference (BI) produced similar tree topology except variation in the bootstrap support values. There were two major clades - (1) A. cantonensis and A. malaysiensis, and (2) A. costaricensis and A. vasorum. The three geographical isolates of A. cantonensis formed a clade with low to high bootstrap values, and consisted of two subclades: (a) China and Hawaii isolates, and (b) monophyletic Thailand isolate. The individuals of each isolate formed a distinct cluster. In the second major clade, the Europe isolates of A. vasorum were distinctly different from the Brazil isolates. For A. costaricensis, the Costa Rica isolate was distinct from the Brazil isolate with an uncorrected (p) distance of 11.39%, indicating the possible occurrence of cryptic species. The present results indicate that COI sequences might be a useful marker for differentiating geographical isolates of A. cantonensis and in uncovering cryptic species. Efforts are being made to carry out an extensive collaborative study to cover a wide range of Angiostrongylus species and geographical isolates.

The giant African snail Achatina fulica as natural intermediate host of Angiostrongylus cantonensis in Pernambuco, northeast Brazil

The human cases of eosinophilic meningitis recently reported from Brazil have focused the attention of the public health agencies on the role the introduced snail Achatina fulica plays as hosts of the metastrongylid nematodes. Determining the potential of this snail to host and develop infective larval stages of metastrongylids in the wild and identify the species harbored by them is crucial for designing effective control measures. Here we assess if A. fulica may act as intermediate host of A. cantonensis at the peridomiciliary areas of a patient's house from state of Pernambuco (PE), who was diagnosed with eosinophilic meningitis and a history of ingesting raw molluscs. Larvae obtained from naturally infected A. fulica were orally administered to Rattus norvegicus. The worms were collected from the pulmonary artery and brain, and were morphologically characterized and compared to the Japan isolate of A. cantonensis. Adult worms and infective L(3) larvae (PE isolate) recovered from A. fulica specimens were also analyzed by polymerase chain reaction and restriction fragment length polymorphism of ITS2 region from rDNA and compared to A. cantonensis (ES isolate), A. vasorum (MG isolate) and A. costaricensis (RS isolate). The large size of the spicules (greater than those observed in other species of Angiostrongylus) and the pattern of the bursal rays agree with the original species description by Chen (1935). Furthermore, the morphology of the PE isolate was similar to that of Japan isolate. The PCR-RFLP profiles obtained were distinctive among species and no variation in patterns was detected among adult individuals from A. cantonensis isolates from PE and ES. The importance of A. fulica as an intermediate host of eosinophilic menigoencepahlitis in Brazil is emphasized.

Angiostrongylus species in wild carnivores in the Iberian Peninsula

A survey of Angiostrongylus parasites was carried out between 2003 and 2006 in wild carnivore species in the Basque Country (Northern Spain). Parasitological examination consisted in the dissection of heart and lungs for the extraction of adult worms. Nematodes were identified using morphometrical features and also PCR amplification and sequencing analysis. The animal species included in this study were Eurasian badger (Meles meles), Weasel (Mustela nivalis), Beech marten (Martes foina), Pine marten (Martes martes), Polecat (Mustela putorius), American mink (Mustela vison), Red fox (Vulpes vulpes), Wolf (Canis lupus), Wild cat (Felis silvestris), and Small-spotted genet (Genetta genetta). Angiostrongylus parasites were only found in foxes and badgers at prevalences of 33.3% and 24%, respectively. Identification of the nematodes by morphometrical features revealed that foxes were infected with A. vasorum while badgers were infected by a different species of Angiostrongylus most likely A. daskalovi. Sequencing data of the second internal transcribed spacer region of ribosomal DNA (ITS2) of isolates from each species confirmed the species difference. The high prevalence of Angiostrongylus found in the present survey, indicates that the wild cycle of two different species of Angiostrongylus is present in the Basque Country. To our knowledge this is the first report of A. daskalovi in the Iberian Peninsula.

Finding of Parastrongylus cantonensis (Chen, 1935) in Rattus rattus in Tenerife, Canary Islands (Spain)

Parastrongylus cantonensis is a parasite of murid rodents that can infect humans and cause health problems as eosinophilic meningitis. Although it is endemic in south Asia, the Pacific islands, Australia, USA, and a few Caribbean islands, it has been extended to new geographical regions. In the Canary Islands (Spain) a survey of helminths of Rattus rattus, Rattus norvegicus and Mus musculus domesticus was carried out. Furthermore, five species of molluscs were examined for nematode larvae to determine whether they are potential intermediate hosts of P. cantonensis. Nematodes were found in the lungs of 15% of 67 R. rattus examined in Tenerife, one of the four studied islands, with a prevalence of 20% in the highest focus of infection. Based on morphological and molecular analysis, with the complete internal transcribed spacer 2 (ITS-2) and a fragment of the small subunit ribosomal RNA (SSU rRNA) nucleotide sequences, nematodes were identified as P. cantonensis. Larval nematodes found from snails and slugs were identified as third-stage (L(3)) Metastrongyloidea, but the molecular study showed that they did not belong to P. cantonensis. This is the first finding of angiostrongyliasis in rats in the Canary Islands (Spain). New molecular data for this species and Parastrongylus dujardini are reported. The presence of P. cantonensis in Tenerife could be of importance from the public health point of view. Further studies are required in order to look for other potential foci of infections in the Canary Islands.

PCR detection of Angiostrongylus vasorum in faecal samples of dogs and foxes

The cardiovascular nematode Angiostrongylus vasorum is spreading in the fox and dog populations of northern Europe. A. vasorum can result in severe clinical manifestations in dogs; therefore, specific diagnosis is crucial for assessing its prevalence. In the present study, faecal samples from foxes and domestic dogs were tested by a new polymerase chain reaction (PCR) targeting the second internal transcribed region of the ribosomal DNA (ITS2) of A. vasorum. Initial isolation of faecal larvae by sieving facilitated the processing of larger sample volumes and allowed for the recovery of dead larvae from frozen samples. The sieve-PCR method enabled the identification of a single larva per 2 g of faecal sample and did not amplify DNA of a range of canine helminths, thus presenting a non-invasive tool for wildlife surveillance and for confirmative diagnosis in dogs.

Angiostrongylus vasorumfrom South America and Europe represent distinct lineages

Angiostrongylus vasorumis a nematode parasite of sylvan and domestic species of the family Canidae. It has a broad but patchy distribution worldwide, and there is evidence for geographical spread and increasing incidence of infection in recent years. While historicallyAngiostrongylus-like nematodes identified in dogs and foxes have been described asA. vasorumin Europe andAngiocaulus raillietiin South America, more recent taxonomic revision has amalgamated these into a single species,A. vasorum. Here we report, for the first time, the molecular characterization of isolates ofA. vasorumfrom Germany, Portugal, Denmark and the United Kingdom on the basis of the mitochondrial COI gene and the second ribosomal internal transcribed spacer. When compared with isolates from Brazil, sequence analysis revealed 2 distinct genotypes. Estimated rates of evolution based on COI sequences for both nematode and host are consistent with the hypothesis that the presence ofA. vasorumin South America is a result of an ancient evolutionary event.Angiostrongylus vasorumin South America potentially represents a separate species to that observed in Europe.

Disseminated angiostrongylosis with fatal cerebral haemorrhages in two dogs in Germany: a clinical case study

Canine angiostrongylosis is a nematode infection in domestic dogs and wild carnivores. Few single case reports describing the occurrence of this disease in Germany exist and until recently angiostrongylosis has not been considered endemic in this country. The present report focuses on clinical, pathological and parasitological findings in two cases of fatal disseminated canine angiostrongylosis associated with multifocal haemorrhages in the central nervous system. Both animals, which lived in Germany, presented with rapidly progressive neurological signs including depression, ataxia, unilateral central blindness and epileptic seizures. Blood work revealed grossly elevated D-dimers and mild thrombocytopenia. Both animals were subsequently euthanised due to progressive clinical aggravation. Necropsy showed cerebral and lung haemorrhages in both animals. Multiple sections of nematode larvae consistent with Angiostrongylus vasorum were identified on histopathological sections of the brain, heart, kidney and lung in both animals and a predominantly granulomatous inflammation with the occurrence of multinucleated giant cells was observed. Adult nematodes were found in the larger lung arteries of one dog and Angiostrongylus infection was subsequently confirmed by PCR-analysis and sequencing in both dogs. A. vasorum larvae were not detected by faecal Baermann examination performed in one of the dogs. It was concluded that canine angiostrongylosis should be considered as differential diagnosis in dogs in Germany, even if faecal examination is negative. There is currently still a lack of studies investigating the occurrence of angiostrongylosis in dogs and intermediate hosts in Germany which would be necessary to survey the endemic realities of this disease.

First record of molluscs naturally infected with Angiostrongylus cantonensis (Chen, 1935) (Nematoda: Metastrongylidae) in Brazil

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 São Vicente, state of São Paulo, also showed genetic profiles of this nematode. This is the first record of Brazilian molluscs infected with this nematode species.

Feline aelurostrongylosis and canine angiostrongylosis: a challenging diagnosis for two emerging verminous pneumonia infections

Aelurostrongylus abstrusus and Angiostrongylus vasorum (Nematoda, Metastrongyloidea) are causative agents of verminous feline and canine pneumonia. Both are presently emerging in several geographical areas and are of major clinical importance. Given the range of parasitic and non-parasitic pathogens which may cause cardio-respiratory distress in dogs and cats, the unequivocal specific diagnosis of both diseases is pivotal for unravelling their epidemiology and central to therapy and control. Several conventional clinico-pathologic, diagnostic imaging and parasitological approaches are currently used in practice, but all have major limitations in the specific diagnosis of these diseases. Serological methods have shown promise in the diagnosis of A. abstrusus and A. vasorum infections, but no clinically useful tests are currently available. Additionally, there have been major advances in the development of novel molecular diagnostic tools for feline aelurostrongylosis, but efforts to develop molecular diagnostic tests are still preliminary for angiostrongylosis. This article provides a review of A. abstrusus and A. vasorum infections in cats and dogs, focusing on the advantages and shortcomings of classical diagnostic methodologies and on present diagnostic advances as well as future perspectives instrumental to epidemiological and clinical studies.

The small subunit (SSU) ribosomal (r) RNA gene as a genetic marker for identifying infective 3rd juvenile stage Angiostrongylus cantonensis

We have developed a molecular method using PCR-direct sequencing to identify the infective 3rd juvenile stage of Angiostrongylus cantonensis, a nematode parasite of rodents that can accidentally infect humans and cause eosinophilic meningitis. We demonstrate that the 5' end of the small subunit (SSU) ribosomal (r) RNA gene is a suitable marker to identify A. cantonensis and distinguish it from other closely related Angiostrongylus species. When the SSU rRNA marker was employed on nematode populations extracted from the black slug Laevicaulis altae collected in 2 test sites in the Philippines, the infective 3rd juvenile stage A. cantonensis was detected without difficulty. The phylogenetic position of other non-angiostrongylid nematodes isolated was also determined. The molecular technique developed in this study provides a rapid and accurate method for the identification of A. cantonensis when morphological identification proves difficult or inadequate.

Canine pulmonary angiostrongylosis: an update

Canine pulmonary angiostrongylosis is an emerging snail-borne disease causing verminous pneumonia and coagulopathy in dogs. The parasite is found in Europe, North and South America and Africa, covering tropical, subtropical and temperate regions. Its distribution has been characterised by isolated endemic foci, with only sporadic occurrences outside these areas. In the last two decades, the literature has been dominated by several case reports and small case series describing sporadic disease in old or new endemic areas. Case reports and experimental studies with high doses of infective third stage larvae may not reflect what happens under field conditions. There is insufficient understanding of the spread of infection and the dynamic consequences of this parasite in the canine population. This review discusses the biology, epidemiology, clinical aspects and management of canine pulmonary angiostrongylosis.