Angiostrongylus Cantonensis Research Articles

Occurrence of Angiostrongylus cantonensis in rodents from the rice granary of the Philippines and associated risk factors for zoonotic transmission.

Rattus tanezumi and Rattus norvegicus are the most common rodent species in the Philippines, with the former mainly inhabiting agricultural land and the latter in urban areas. Generating information on the Angiostrongylus cantonensis harbored by these rodents would be useful for public health. A total of 600 rodents were collected from traps placed each month from July to December 2012 in selected villages of Muñoz, Nueva Ecija; the rice granary of the Philippines. The prevalence of A. cantonensis in R. tanezumi and R. norvegicus was, 100%; all the rodents from the five villages were infected. The study shows that regardless of stages, body weight and length, rodents are vulnerable to infection by Angiostrongylus cantonensis present in the environment. However in terms of sex, results revelead that the male and female in R. tanezumi has no statistically significance while R. norvegicus revealed that male and female has statistically significance.This study also show that, rodents that were caught in the agricultural area has higher mean intensity compared to rodents that were trapped in the residential areasbut found to be insignificant. Also through survey interviews the various risk factors with zoonotic implication of A. cantonensis in the area was also discussed.

Eosinophilic Meningoencephalitis Due to Angiostrongylus cantonensis Presenting as Fever of Unknown Origin

A previously healthy 19 month old female, former 34-week gestational age, was admitted to the acute care floor after a one month history of daily fevers to 39.4 C-40.0 C and new onset ataxia. She was seen on multiple occasions by her pediatrician for fever, initially diagnosed with a viral illness, and later completed a ten day course of amoxicillin for otitis media. Along with persistent daily fevers, she was noted by her mother to be progressively more irritable and off-balance, progressing to the point that she was unable to ambulate. She was living in Houston, …

Eosinophilic Meningoencephalitis Due to Angiostrongylus cantonensis Presenting as Fever of Unknown Origin

Eosinophilic Meningoencephalitis Due to Angiostrongylus cantonensis Presenting as Fever of Unknown Origin

Updated distribution and experimental life-history traits of the recently invasive snail Lissachatina fulica in Havana, Cuba

The giant African snail Lissachatina fulica has been reported invading Cuba since 2014 and is now well established in areas of Havana and several nearby regions. This invasive species is of major concern to health authorities given its role as an important vector of parasites such as Angiostrongylus cantonensis, the causative agent of eosinophilic meningoencephalitis in humans. Here, we update the distribution within Cuba. We also report on our studies of experimental life-history traits to assess the population dynamics and potential for spread of this species in Cuba. The experimental population had a very low probability of dying at first age intervals (Type I survival curve) with a life expectancy of 71 weeks. During our experiment, sexual maturity was reached after 22 weeks (individuals of 70 mm shell length) and eggs were laid regularly (mean batch size: 188 ± 111.79 SD). We failed to detect any deviations from the mortality curve and individuals reached an average of 77.3 mm (shell length) and weighted 57.7 g after one year. Predicted curve models indicate that snails reaching their average lifespan of five years should attain 10–12 cm (shell length) and weight 160 g. The spreading of this invasive and vector snail has been tracked for four years in Cuba showing a steady increase of invaded localities. How fast and how far this species develops in Cuba is unknown but the life history parameters indicated in this paper show that it has a large potential to invade all areas of Cuba quickly unless a systematic abatement strategy is developed.

Bulimulus tenuissimus (mollusca) as a new potential host of Angiostrogylus cantonensis (nematoda), a histological and metabolic study.

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

Intrathecal activation of the lectin pathway in patients with eosinophilic meningitis by Angiostrongylus cantonensis

Eosinophilic meningitis produced by Angiostrongylus cantonensis is an emerging disease in Western hemisphere. MBL and H‐ and M‐ficolins are starters of the lectin pathway.ObjectiveTo determine if MBL and H‐ and M‐ficolins can be synthesizedin central nervous system in patients suffering from eosinophilic meningitis due to Angiostrongylus cantonensis.Methods19 serum and CSF paired samples were obtained from pediatric patients with the diagnosis of eosinophilic meningitis by Angiostrongylus cantonensis. Cerebrospinal fluid was obtained by lumbar puncture and serum from blood was taken by venopuncture. Serum and CSF was stored frozen in aliquots at −80°C until analysis.The local ethics committee approved this study and all patients' tutors gave informed consent.CSF and serum albumin were quantified by immunochemical nephelometry with kinetic analysis. MBL and H‐ and M‐ficolins were measured by commercial enzyme‐linked immunosorbent assay (ELISA) kit.The MBL reibergram was employed in order to determine if MBL can be synthesized inthecentral nervous system or not. The H‐ and M‐ficolins regressions were employed in order to determine if H‐ and M‐ficolins can be synthesized in the central nervous system or not.Results8 patients do not have dysfunction of blood/CSF barrier and 4 patients have intratecal synthesis of MBL.One patient do not have intrathecal synthesis of H‐ficolin (Figure 2A) and all patients have intrathecal synthesis of M‐ficolin (Figure 2B).ConclusionsIntrathecal activation of the lectin pathway by at least one of the quantified starters in this group of patients with eosinophilic meningitis due to Angiostrongylus cantonensis.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Hurdles in the evolutionary epidemiology of Angiostrongylus cantonensis: Pseudogenes, incongruence between taxonomy and DNA sequence variants, and cryptic lineages.

Angiostrongylus cantonensis, the rat lungworm, is a zoonotic pathogen that is one of the leading causes of eosinophilic meningitis worldwide. This parasite is regarded as an emerging pathogen with a global range expansion out of southeastern Asia post‐WWII. To date, molecular systematic/phylogeographic studies on A. cantonensis have mainly used two mitochondrial (mtDNA) markers, cytochrome c oxidase 1 (CO1) and cytochrome b (CYTB), where the focus has largely been descriptive in terms of reporting local patterns of haplotype variants. In order to look for more global evolutionary patterns, we herein provide a collective phylogenetic assessment using the six available whole mtDNA genome samples that have been tagged as A. cantonensis, A. malaysiensis, or A. mackerrasae along with all other GenBank CO1 and CYTB partial sequences that carry these species identifiers. The results reveal three important complications that researchers will need to be aware of, or will need to resolve, prior to conducting future molecular evolutionary studies on A. cantonensis. These three problems are (i) incongruence between taxonomic identifications and mtDNA variants (haplotypes or whole mtDNA genome samples), (ii) the presence of a CYTB mtDNA pseudogene, and (iii) the need to verify A. mackerrasae as a species along with other possible cryptic lineages, of which there is suggestive evidence (i.e., A. cantonensis could be a species complex). We provided a discussion of how these complications are hurdles to our understanding of the global epidemiology of angiostrongyliasis. We call for future studies to be more explicit in morphological traits used for identifications (e.g., provide measurements). Moreover, it will be necessary to repeat prior morphological and life‐history studies while simultaneously using sequence data in order to assess possible associations between critical epidemiological data (e.g., biogeography, virulence/pathology, host species use) and specific lineages.

Invasive Pomacea snails as important intermediate hosts of Angiostrongylus cantonensis in Laos, Cambodia and Vietnam: Implications for outbreaks of eosinophilic meningitis

The rat lungworm Angiostrongylus cantonensis causes human eosinophilic meningitis and it is endemic in Southeast Asia, but little is known about its distribution in Laos, Cambodia and Vietnam. We conducted a multi-country survey for A. cantonensis in these countries to estimate its prevalence in snails along the Mekong River and the east coast of Vietnam. We identified Angiostrongylus species by morphological and molecular analysis. We found A. cantonensis in the invasive snail, Pomacea spp. The wide accessibility of Pomacea snails, along with their infection by A. cantonensis, indicates that this snail species could be used in surveillance for preventing outbreaks of eosinophilic meningitis.

Heterologous expression of three antigenic proteins from Angiostrongylus cantonensis: ES-7, Lec-5, and 14-3-3 in mammalian cells

Angiostrongylus cantonensis is a parasitic nematode and the main causative agent of human cerebral eosinophilic meningoencephalitis (EoM). A definitive diagnosis of EoM usually requires serologic or molecular analysis of the patient’s clinical sample. Currently, a 31 kDa antigen is used in immunological tests for this purpose, however as a crude antigen preparation it may present cross-reactivity with other helminthic infections, especially echinococcosis. Heterologous expression studies using prokaryotic systems failed on producing antigenic proteins. The aim of this study was to express and purify three recombinant glycoproteins representing A. cantonensis antigens: ES-7, Lec-5, and 14-3-3, in Chinese hamster ovary (CHO) cells and ES-7 in human embryonic kidney (HEK) cells to develop a source of specific antigens to be used in the diagnosis of angiostrongyliasis. The potential diagnostic value of these three proteins was subsequently characterized in one- and two-dimensional electrophoresis and Western blot to dot blot analyses, with Angiostrongylus-positive sera, normal human sera (NHS), and a pool of Echinococcus-positive sera (included as a specificity control) used for detection. In addition, recognition of these three proteins following treatment with N-glycosidase F was examined. The ES-7 proteins that were expressed in HEK and CHO cells, and the Lec-5 protein that was expressed in CHO cells, were specifically recognized by A. cantonensis-positive sera in the 2D electrophoresis analysis. This recognition was shown to be dependent on the presence of glycidic portions, making mammalian cells a very promising source of heterologous expression antigenic proteins from Angiostrongylus.

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

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. To develop a qPCR multiple test to identify the three pathogenic species of Angiostrongylus. 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. 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%). A multiple qPCR was standardized at the laboratory for three clinically significant species of Angiostrongylus.

Genotyping and polymorphism analysis of cytochrome c oxidase subunit Ⅰ gene of Pomacea canaliculata from Lincang City in Yunnan Province

To analyze the genetic diversity of Pomacea canaliculata based on the mitochondria DNA cytochrome c oxidase subunit Ⅰ (mtDNA COⅠ) gene as a molecular marker in Lincang City of Yunnan Province, so as to provide the scientific data for monitoring Angiostrongylus cantonensis in local areas. The genotypes and polymorphisms of 38 specimens of P. canaliculata collected from Mengding Town of Lincang City were analyzed by sequencing COⅠ gene. The phylogenetic tree and genetic distances were produced based on the haplotypes from GenBank and the present study by using the neighbourjoining method with the software MEGA version 6.06. Totally 31 sequences were acquired in the present study and they produced 3 unique haplotypes. Haplotype 1 showed a higher frequency compared to the others and it accounted for 83.9 % (26/31). The data showed that the least genetic distances ranged from 0 to 0.052 between P. canaliculata and 3 haplotypes, as well as the largest genetic distances ranged from 0.021 to 0.239 between Pila conica and 3 haplotypes. Otherwise, the analysis of the phylogenetic trees based on COⅠ gene sequences of P. canaliculata indicated that all of 3 haplotypes clustered into one big clade with that from Japan (GenBank accession number: AB433769), China (GenBank accession number: KT313034) and USA (GenBank accession number: EU523129), which owned the closet relationship amongst them. Their genetic relationships were distantly related to the GenBank's reference sequences of P. insularum (GenBank accession number: EF514942), P. camena (GenBank accession number: EF515059) and so on. There is a P. canaliculata species in Lincang City of Yunnan Province as well as a high genetic diversity amongst the acquired 3 haplotypes in this study.

CASE REPORT: ANGIOSTRONGYLIASIS IN A PALLAS’S SQUIRREL (CALLOSCIURUS ERYTHRAEUS)

This is a rare case of a wild squirrel that was diagnosed with angiostrongyliasis characterized by the presence of larvae-induced eosinophilic meningoencephalomyelitis. A wild, intact, male Pallas’s squirrel (Callosciurus erythraeus) of unknown age was presented with a history of progressive paralysis in both forelimbs and hindlimbs. Gradually, the squirrel showed signs of deterioration, found dead and submitted for a complete pathological diagnosis. Necropsy revealed the presence of severe and diffuse congestion in the subarachnoid space of the brain and mild congestion in the spinal cord. Microscopically, severe meningoencephalomyelitis and interstitial pneumonia were consistent with lesions induced by Angiostrongylus cantonensis (A. cantonensis). Although A. cantonensis has been widely studied in rabbits, mice and humans, infection in squirrels has not been documented. This may be the first reported case of angiostrongyliasis in the Pallas’s squirrel.

Validation by qPCR of Reference Genes for Reproductive Studies in the Invasive Apple SnailPomacea canaliculata

The South American freshwater gastropod Pomacea canaliculata is a highly invasive species. In introduced areas, it is a serious crop pest, responsible for great economic loss and ecological damage. It is also a vector of the nematode Angiostrongylus cantonensis that causes human meningoencephalitis. Many aspects and particularly its reproduction have been extensively studied, but little research has been conducted on this species regarding gene expression. To meaningfully interpret quantitative PCR, a powerful technique to develop this kind of study, validation of reference genes is essential but until now has not been undertaken. We selected the female albumen gland for its major role in egg production in order to evaluate the expression stability of the candidate reference genes EF1-α, RPL7, His H3.3, TUBB, 18S RNA, ACTB and GAPDH. Stability was analyzed under different reproductive activity conditions and defined based on three approaches: geNorm, NormFinder and the comparative ΔCt method. NormFinder selected GAPDH and ACTB as the best option to be used for normalization, whereas geNorm and the comparative ΔCt method indicate RPL7, GAPDH, and 18S RNA as the most stable genes under the conditions studied. These results will facilitate reproductive studies, particularly those using qPCR to evaluate factors that may affect fecundity of this conspicuous invasive species.

Correction: Diverse Gastropod Hosts of Angiostrongylus cantonensis, the Rat Lungworm, Globally and with a Focus on the Hawaiian Islands.

[This corrects the article DOI: 10.1371/journal.pone.0094969.].

Role of Gastropod Mucus in the Transmission of Angiostrongylus cantonensis, a Potentially Serious Neurological Infection.

Angiostrongylus cantonensis, the rat lungworm, is endemic to Hawaii. A recent increase in the number of cases has drawn intense local and national media attention. As a result there is an increased fear of acquiring the disease from local produce, which has the potential to adversely affect the income of local farmers. The most common means of transmission is by the ingestion of an infected intermediate host. Other modes of transmission have been suggested including infectious larvae being released into the mucus trail of gastropods. This literature review indicates that mucus trails from infected gastropods poses a minimal risk to humans.

Achatina fulica infected by Angiostrongylus cantonensis on beaches, in the west zone of Rio de Janeiro, Brazil.

ABSTRACT Angiostrongylus cantonensis is considered the main etiological agent of eosinophilic meningitis in humans. At present, this zoonosis is considered an emerging disease mainly in the Americas. The aim of this study was to determine the prevalence of Achatina fulica infected by Angiostrongylus cantonensis in restinga areas along beaches in the west zone of Rio de Janeiro city, Brazil. The study areas included the following beaches: Barra da Tijuca, Recreio dos Bandeirantes, Reserva, Prainha and Grumari. Ninety specimens of Achatina fulica were collected. Positive molluscs were found only in Barra da Tijuca. Infection prevalence was 5.5%. The presence of this parasite in the beachfront areas, in the west zone of Rio de Janeiro city demonstrates the potential risk of infection for visitors and the expansion of this helminth in the State of Rio de Janeiro.

Diagnosing and Understanding Angiostrongyliasis, A Zoonotic Cause of Meningitis.

Eosinophilic meningitis caused by Angiostrongylus cantonensis is spreading worldwide, and it can manifest as a severe neurological disease. Angiostrongyliasis is a food- and water-borne parasitosis that usually exhibits a seasonal and circumscribed geographical distribution. To improve control and treatment of these infections, further studies of transmission dynamics under natural conditions and the development of better diagnostic tools and treatment options are needed.

Angiostrongyliasis or Rat Lungworm Disease: a Perspective From Hawai'i

Purpose of Review Angiostrongyliasis is contracted by the ingestion of or exposure to the zoonotic parasite Angiostrongylus cantonensis, which requires two hosts to complete its life cycle. Rats are known to be the definitive hosts and mollusks are intermediate hosts. It is the intermediate host, or infected paratenic hosts that can pass the infective stage of the disease to humans and other susceptible animals. The purpose of this review is to examine the growing threat of A. cantonensis and its consequences, with particular emphasis on Hawai'i.

Chi3l3: a potential key orchestrator of eosinophil recruitment in meningitis induced by Angiostrongylus cantonensis

BackgroundAngiostrongylus cantonensis, an important foodborne parasite, can induce serious eosinophilic meningitis in non-permissive hosts, such as mouse and human. However, the characteristics and mechanisms of the infection are still poorly understood. This study sought to determine the key molecules and its underlying mechanism in inducing brain eosinophilic infiltration caused by Angiostrongylus cantonensis.MethodsMathematical models were established for prediction of significantly changing genes and the functional associated protein with RNA-seq data in Angiostrongylus cantonensis infection. The expression level of Chi3l3, the predicted key molecule, was verified using Western blotting and real-time quantitative PCR. Critical cell source of Chi3l3 and its relationship with eosinophils were identified with flow cytometry, immunohistochemistry, and further verified by macrophage depletion using liposomal clodronate. The role of soluble antigens of Angiostrongylus cantonensis in eosinophilic response was identified with mice airway allergy model by intranasal administration of Alternaria alternate. The relationship between Chi3l3 and IL-13 was identified with flow cytometry, Western blotting, and Seahorse Bioscience extracellular flux analyzer.ResultsWe analyzed the skewed cytokine pattern in brains of Angiostrongylus cantonensis-infected mice and found Chi3l3 to be an important molecule, which increased sharply during the infection. The percentage of inflammatory macrophages, the main source of Chi3l3, also increased, in line with eosinophils percentage in the brain. Network analysis and mathematical modeling predirect a functional association between Chi3l3 and IL-13. Further experiments verified that the soluble antigen of Angiostrongylus cantonensis induce brain eosinophilic meningitis via aggravating a positive feedback loop between IL-13 and Chi3l3.ConclusionsWe present evidences in favor of a key role for macrophave-derived Chi3l3 molecule in the infection of Angiostrongylus cantonensis, which aggravates eosinophilic meningitis induced by Angiostrongylus cantonensis via a IL-13-mediated positive feedback loop. These reported results constitute a starting point for future research of angiostrongyliasis pathogenesis and imply that targeting chitinases and chitinase-like-proteins may be clinically beneficial in Angiostrongylus cantonensis-induced eosinophilic meningitis.

Challenging the dogma of the ‘Island Syndrome’: a study of helminth parasites of feral cats and black rats on Christmas Island

ABSTRACTMany island ecosystems are exposed to ecological threats through invasive species and the parasites they harbour. Parasites can impact endemic island populations whether they are stable populations or ones already in decline. The ‘Island Syndrome’ hypothesis proposes that richness and diversity of introduced parasites differ from mainland populations with lower parasite species diversity on islands due to the founder effect. To examine the role of ‘Island Syndrome’ and impacts for faunal and human communities on a tropical island, helminth parasites were identified from feral cats (Felis catus) (n = 66) and black rats (Rattus rattus) (n = 101) on Christmas Island. Sixty-one (92 per cent) of cats and 85 (84 per cent) of rats harboured one or more helminth species with total infra-community richness (TICR) ranging over zero to six species in cats and zero to seven species in rats, including species of zoonotic significance (Angiostrongylus cantonensis, Toxocara cati, Ancylostoma braziliense, Taenia taeniaeformis, Moniliformis moniliformis and Hymenolepis nana). High parasite prevalence and TICR were expected in island populations; however, high parasite richness in cats and rats on Christmas Island was counter to the ‘Island Syndrome’. These results suggest that introduced cats and rats may be responsible for maintaining an increased parasitological threat to fauna and human communities in certain ecosystems.