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Memorias Do Instituto Oswaldo Cruz 2020Intermediate hosts are key organisms in maintaining parasite life cycles, because they can act as amplifiers in the transmission from natural reservoirs to humans. One... (Review)
Review
BACKGROUND
Intermediate hosts are key organisms in maintaining parasite life cycles, because they can act as amplifiers in the transmission from natural reservoirs to humans. One of the most important groups of intermediate hosts for zoonotic nematode infections are gastropods,slugs and snails. These are essential organisms in the larval development of Angiostrongylus species.
OBJECTIVES
The objective of this paper is to review reports of Angiostrongylus spp. in naturally infected gastropods from the Americas, taking into account the diagnostic methods used in their identification, to be able to provide more accurate list of their intermediate hosts. We also discuss the factors that aid the dispersion of Angiostrongylus spp. in the Americas.
METHODS
This study reviews scientific publications and book sections on Angiostrongylus spp. in the Americas, including original works assessing larvae of Angiostrongylus in intermediate hosts. The eligible reports were classified accordingly to their geographical location, year of first record, and the larvae identification methodologies used. Digital repositories were used for the search. The bioecological characteristics of the main intermediate hosts are summarised.
FINDINGS
A total of 29 gastropod species that are naturally infected with Angiostrongylus spp. have been reported as intermediate hosts, 16 of which are land snails, two are freshwater snails, and 11 land slugs.
MAIN CONCLUSIONS
This study highlights the importance of integrative studies, analysing both the etiological agent and its transmission dynamic in the environment, the biological and ecological characteristics of the hosts, and the impact on host populations. It is necessary to increase interdisciplinary studies to determine the potential epidemiological health risk of angiostrongyliasis in the Americas, and thus be able to establish prevention, monitoring and contingency strategies in the region.
Topics: Americas; Angiostrongylus; Angiostrongylus cantonensis; Animals; Disease Vectors; Gastropoda; Humans; Snails; Strongylida Infections; Zoonoses
PubMed: 33263610
DOI: 10.1590/0074-02760200236 -
Hawai'i Journal of Medicine & Public... Jun 2013Human infection with the rat lungworm, Angiostrongylus cantonensis, is characterized by a vigorous eosinophil response that gives the disease its name, eosinophilic... (Review)
Review
Human infection with the rat lungworm, Angiostrongylus cantonensis, is characterized by a vigorous eosinophil response that gives the disease its name, eosinophilic meningitis. The actual role eosinophils play, both protective and destructive, in this infectious process is still largely a mystery. Research since 2002 has indicated that eosinophils are a multifaceted granulocyte that contributes to a wide range of physiological and pathological processes depending on their location and activation status. This article suggests an expanded role for eosinophils as both classic antiparasitic effector cells and as immune regulatory cells in eosinophilic meningitis caused by Angiostrongylus cantonensis.
Topics: Angiostrongylus cantonensis; Animals; Eosinophilia; Eosinophils; Humans; Immunity, Cellular; Meningitis; Strongylida Infections
PubMed: 23901384
DOI: No ID Found -
Parasites & Vectors Mar 2016Nematodes of the genus Angiostrongylus are important causes of potentially life-threatening diseases in several animal species and humans. Angiostrongylus vasorum... (Review)
Review
BACKGROUND
Nematodes of the genus Angiostrongylus are important causes of potentially life-threatening diseases in several animal species and humans. Angiostrongylus vasorum affects the right ventricle of the heart and the pulmonary arteries in dogs, red foxes and other carnivores. The diagnosis of canine angiostrongylosis may be challenging due to the wide spectrum of clinical signs. Ocular manifestations have been seldom reported but have serious implications for patients.
METHODS
The clinical history of three cases of infection with A. vasorum in dogs diagnosed in UK, France and Italy, was obtained from clinical records provided by the veterinary surgeons along with information on the diagnostic procedures and treatment. Nematodes collected from the eyes of infected dogs were morphologically identified to the species level and molecularly analysed by the amplification of the nuclear 18S rRNA gene.
RESULTS
On admission, the dogs were presented with various degrees of ocular discomfort and hyphema because of the presence of a motile object in the eye. The three patients had ocular surgery during which nematodes were removed and subsequently morphologically and molecularly identified as two adult males and one female of A. vasorum.
CONCLUSIONS
Three new cases of canine ocular angiostrongylosis are reported along with a review of other published clinical cases to improve the diagnosis and provide clinical recommendation for this parasitic condition. In addition, the significance of migratory patterns of larvae inside the host body is discussed. Veterinary healthcare workers should include canine angiostrongylosis in the differential diagnosis of ocular diseases.
Topics: Angiostrongylus; Animals; DNA, Helminth; DNA, Ribosomal; Dog Diseases; Dogs; Eye; Eye Diseases; France; Italy; Locomotion; Molecular Diagnostic Techniques; Parasitology; RNA, Ribosomal, 18S; Sequence Analysis, DNA; Strongylida Infections; United Kingdom
PubMed: 27000634
DOI: 10.1186/s13071-016-1440-6 -
Veterinary Parasitology Dec 2022Angiostrongylus vasorum is a widely distributed cardiopulmonary parasite of canids in Europe. Clinical signs in dogs can be highly variable and diagnostically...
Adult parasite burden and excretion of first-stage larvae of Angiostrongylus vasorum in dogs: Methodologically relevant diagnostic aspects and associations with serological detection of parasite antigen and specific antibodies.
Angiostrongylus vasorum is a widely distributed cardiopulmonary parasite of canids in Europe. Clinical signs in dogs can be highly variable and diagnostically challenging. A correct and early diagnosis is hence indispensable to adequately manage affected patients. First-stage larvae (L1) are excreted in the faeces of definitive hosts and conventionally identified using the Baermann technique. Moreover, ELISAs for the detection of circulating antigen and specific antibodies have been presented. The current study aimed at i) quantitatively assessing larval migration in the Baermann funnel after 12 h and 24 h; ii) investigating the influence of sample storage at 4 °C over the course of three days on the number of detected L1; iii) evaluating potential associations of adult worm burdens with larval shedding in dogs and ELISA optical density (OD) values for circulating parasite antigen and specific antibodies. Faecal samples were obtained from naturally infected dogs (n = 21) and Baermann funnels were set up in duplicate over the course of four consecutive days (days 0-3) starting with the day of sample collection. Funnels were harvested on days 1-4 after 12 and 24 h, respectively, and the number of L1 per gram faeces (LPG) was determined. The LPG did not differ between larval harvest after 12 h from harvest after 24 h. Storage of faecal samples at 4 °C for two and three days entailed a considerable decrease in LPG. Adult worm burdens and larval excretion data from previous experiments demonstrated a correlation between worm burden and LPG. In contrast, no correlations between worm burden and the level of parasite antigen and specific antibody OD values, respectively, were identified. Thus, OD values of both antigen and antibody ELISA did not allow for conclusions on infection intensity reflected by the number of adult parasites. For the detection of L1 in faeces, 12 or 24 h of larval migration time was not discriminating for A. vasorum positivity. Thus, early processing of faecal samples is essential, since larval detection and hence sensitivity of the approach considerably decreased over the course of three days of storage. Therefore, the common recommendation to collect faecal samples for three consecutive days and to subsequently analyse them needs to be reconsidered. The results of this study can be readily translated into precise recommendations for daily practice to adequately assess A. vasorum infected dogs.
Topics: Dogs; Animals; Angiostrongylus; Parasites; Larva; Strongylida Infections; Antibodies, Helminth; Antigens, Helminth; Dog Diseases
PubMed: 36274434
DOI: 10.1016/j.vetpar.2022.109814 -
Parasites & Vectors Feb 2024The closely related Angiostrongylus cantonensis and Angiostrongylus malaysiensis have been reported to coexist in Thailand and share similar hosts and life cycles....
BACKGROUND
The closely related Angiostrongylus cantonensis and Angiostrongylus malaysiensis have been reported to coexist in Thailand and share similar hosts and life cycles. Recently, in an angiostrongyliasis outbreak in Thailand, both A. cantonensis and A. malaysiensis were found in the cerebrospinal fluid of affected patients. Morphological similarities, overlapping distribution, shared hosts and habitats, and the close genetics of the two Angiostrongylus species can complicate accurate species identification. Addressing these challenges, this study aims to evaluate whether a correlation between the morphological and genetic identities of A. cantonensis and A. malaysiensis can improve species identification accuracy.
METHODS
Angiostrongylus spp. specimens from five zoogeographical regions in Thailand were subjected to morphological and molecular identification using the mitochondrial cytochrome b gene and the nuclear internal transcribed spacer 2 region (ITS2). The morphological characters for males and females were then validated using the species identity obtained from the nuclear ITS2 region.
RESULTS
The results revealed that morphological misidentifications between these two closely related species are common due to overlapping morphological characters. Although certain male traits such as body length and width aided species differentiation, female traits were found to be less reliable. Furthermore, hybrid forms (8.2%) were revealed through the ITS2 results, which can further complicate morphological identification. Mito-nuclear discordance was also present in 1.9% of the Angiostrongylus specimens from Thailand, suggesting a complex historical interbreeding between the species.
CONCLUSIONS
Based on our findings, we suggest that nuclear ITS2 is a reliable marker for species identification of A. cantonensis and A. malaysiensis, especially in regions where both species coexist. Additionally, the scope and consequences of hybridization between the two closely related Angiostrongylus species should be further investigated in Thailand.
Topics: Humans; Animals; Male; Female; Angiostrongylus; Angiostrongylus cantonensis; Phylogeny; Phenotype; Strongylida Infections
PubMed: 38326886
DOI: 10.1186/s13071-024-06140-9 -
Tropical Biomedicine Dec 2014The rat lungworm Angiostrongylus cantonensis, a food-borne zoonotic parasite, has been recognized as the primary pathogen associated with human eosinophilic meningitis... (Review)
Review
The rat lungworm Angiostrongylus cantonensis, a food-borne zoonotic parasite, has been recognized as the primary pathogen associated with human eosinophilic meningitis or eosinophilic meningoencephalitis. This neurotropic nematode has a definitive rodent host and a molluscan intermediate host. The adult worms live in the pulmonary arteries of rats. Human is a non-permissive, accidental host. Transmission to humans is by eating of infected raw or undercooked snails, poorly cleaned contaminated vegetables or other infected paratenic hosts such as freshwater prawns, crabs, frogs or monitor lizards. Thousands of diagnosed cases of eosinophilic meningitis caused by A. cantonensis have been reported worldwide. Angiostrongyliasis is of increasing public health importance as globalization contributes to the geographical spread and more international travelers encounter the disease. The parasite is on the move. It has spread from its traditional endemic areas of Asia and the Pacific Basin to the American continent including the USA, Brazil and Caribbean islands. Recently, the incidence of human infections has increased rapidly. Most reports of the disease are from Thailand and Taiwan with increasing reports from mainland China. The rapid global spread of the parasite and the emerging occurrence of the infection pose challenges in clinical and laboratory diagnosis, and in epidemiology and basic biology. Enhanced understanding of the epidemiology of angiostrongyliasis, increased public awareness about the risks associated with eating raw or undercooked food, and enhanced food safety measures are needed. Therefore, current knowledge on various aspects of the parasite and the disease it causes, as well as recent epidemiological status together with significant progress in laboratory investigation of A. cantonensis infection, are overviewed to promote understanding and awareness of this emerging neglected disease.
Topics: Angiostrongylus cantonensis; Animals; Communicable Diseases, Emerging; Foodborne Diseases; Global Health; Humans; Incidence; Meningitis; Neglected Diseases; Strongylida Infections
PubMed: 25776582
DOI: No ID Found -
Hawai'i Journal of Medicine & Public... Jun 2013The metastrongyloid nematode genus Angiostrongylus includes 18 species, two of which are relevant from a medical standpoint, Angiostrongylus costaricensis and...
The metastrongyloid nematode genus Angiostrongylus includes 18 species, two of which are relevant from a medical standpoint, Angiostrongylus costaricensis and Angiostrongylus cantonensis. The first was described from Costa Rica in 1971 and causes abdominal angiostrongyliasis in the Americas, including in Brazil. Angiostrongylus cantonensis, first described in 1935 from Canton, China, is the causative agent of eosinophilic meningitis. The natural definitive hosts are rodents, and molluscs are the intermediate hosts. Paratenic or carrier hosts include crabs, freshwater shrimp, amphibians, flatworms, and fish. Humans become infected accidentally by ingestion of intermediate or paratenic hosts and the parasite does not complete the life cycle as it does in rats. Worms in the brain cause eosinophilic meningitis. This zoonosis, widespread in Southeast Asia and the Pacific islands, has now been reported from other regions. In the Americas there are records from the United States, Cuba, Jamaica, Brazil, Ecuador, and Haiti. In Brazil seven human cases have been reported since 2007 from the southeastern and northeastern regions. Epidemiological studies found infected specimens of Rattus norvegicus and Rattus rattus as well as many species of molluscs, including the giant African land snail, Achatina fulica, from various regions of Brazil. The spread of angiostrongyliasis is currently a matter of concern in Brazil.
Topics: Angiostrongylus cantonensis; Animal Distribution; Animals; Brazil; Communicable Diseases, Emerging; Eosinophilia; Humans; Life Cycle Stages; Meningitis; Rats; Snails; Strongylida Infections
PubMed: 23901376
DOI: No ID Found -
Hawai'i Journal of Medicine & Public... Jun 2013Angiostrongylus Eosinophilic Meningitis is caused by human infection with larvae of the rat lungworm, Angiostrongylus cantonensis. The clinical presentation includes a... (Review)
Review
Angiostrongylus Eosinophilic Meningitis is caused by human infection with larvae of the rat lungworm, Angiostrongylus cantonensis. The clinical presentation includes a spectrum of disease, from meningitis through radiculitis, cranial nerve abnormalities, ataxia, encephalitis, coma, and rarely death. The condition is diagnosed by recognizing the triad of: the clinical syndrome, eosinophils in the cerebrospinal fluid or blood, and exposure history. A history of eating raw or poorly cooked snails is classic, but ingestion of other intermediate hosts or unwashed produce (such as lettuce) harboring hosts is not uncommon. Several serologic tests exist but none has yet been fully validated. There is good evidence that a 2 week course of high dose corticosteroids shortens the duration and severity of symptoms. There is somewhat weaker evidence that albendazole reduces symptoms. The combination of prednisolone and albendazole is being used more commonly for treatment. Some suggestions for future research are given.
Topics: Angiostrongylus cantonensis; Animals; Eosinophilia; Humans; Meningitis; Strongylida Infections
PubMed: 23901382
DOI: No ID Found -
Hawai'i Journal of Medicine & Public... Jun 2013Angiostrongylus cantonensis, the rat lungworm, is a major cause of eosinophilic meningitis in humans. This short paper reviews what is known about the pathways of... (Review)
Review
Angiostrongylus cantonensis, the rat lungworm, is a major cause of eosinophilic meningitis in humans. This short paper reviews what is known about the pathways of infection and assesses the probable importance of each in causing disease. Rats are the definitive hosts. People can become infected by eating, both deliberately and inadvertently, raw or under-cooked intermediate hosts (snails or slugs) or paratenic hosts such as freshwater shrimp, crabs and frogs. Food preparation prior to cooking can leave debris from which infection can also occur. It may be possible to become infected by consuming snail/slug slime (mucus) on produce or by transferring mucus from hands to mouth after handling snails/slugs. Infection from consuming drinking water contaminated by snails/slugs and infection via open wounds may be theoretically possible but no cases have been reported. The severity of the disease is probably related to the number of infective larvae ingested as well as to the precise location of the worms in the host and the host's inflammatory response. Strategies for reducing human infection should include snail and slug control to reduce chances of accidental ingestion, cooking of intermediate and paratenic hosts, and public education on food preparation.
Topics: Angiostrongylus cantonensis; Animals; Anura; Brachyura; Cooking; Eosinophilia; Food Parasitology; Humans; Meningitis; Mucus; Penaeidae; Shellfish; Snails; Strongylida Infections; Vegetables; Water
PubMed: 23901388
DOI: No ID Found -
Journal of Invertebrate Pathology Jan 2014The effect of concurrent infection by Echinostoma paraensei and Angiostrongylus cantonensis on the activity of the enzymes alanine aminotransferase (ALT) and aspartate...
The effect of concurrent infection by Echinostoma paraensei and Angiostrongylus cantonensis on the activity of the enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and the concentration of total proteins, uric acid and urea in the hemolymph of Biomphalaria glabrata were investigated. Additionally, histopathological studies were conducted to better understand the dynamics of ontogenic development of both helminths in the host and the possible biochemical effects. Co-infections by helminths and other parasites often occur due to the wide distribution of helminths and the chronic nature of the infection. The biochemical parameters were measured at the end of the seventh week after exposure. The co-infection resulted in a significant decrease in the total proteins concentration in the hemolymph of snails as well as an increase in the nitrogen excretion products, these results showed that the infection leads to exhaustion of free circulating and stored carbohydrates and the infected snails make use alternative substrates, such as free amino acids. So, the protein degradation to release free amino acids causes a decrease in the content of total proteins in the snail host and an amino acids deamination process, increasing the content of ammonium, which needs to be detoxified. This occurs by increasing the urea and uric acid contents. This observation is corroborated by the increase of ALT and AST activities, enzymes directly related to amino group from an amino acid to an α- ketoacid an important step to generate new carbon skeleton for glucose synthesis de novo, as well as new intermediates to the Krebs cycle. Additionally, reduction in the recovery of L3 from the co-infected group (A + E) was observed, since in this association the burden was higher than in the other. Histopathological results showed a change in the distribution of A. cantonensis in the presence of E. paraensei, indicating that the presence of this trematode impairs the dynamic transmission of A. cantonensis.
Topics: Angiostrongylus cantonensis; Animals; Biomphalaria; Echinostoma; Echinostomiasis; Strongylida Infections
PubMed: 24513030
DOI: 10.1016/j.jip.2013.10.005