RESUMO
Numerous Antarctic species are recognized as reservoirs for various pathogens, and their migratory behavior allows them to reach the Brazilian coast, potentially contributing to the emergence and circulation of new infectious diseases. To address the potential zoonotic risks, we conducted surveillance of influenza A virus (IAV) and coronaviruses (CoVs) in the Antarctic Peninsula, specifically focusing on different bird and mammal species in the region. During the summer of 2021/2022, as part of the Brazilian Antarctic Expedition, we collected and examined a total of 315 fecal samples to target these respiratory viruses. Although we did not detect the viruses of interest during this particular expedition, previous research conducted by our team has shown the presence of the H11N2 subtype of influenza A virus in penguin fecal samples from the same region. Given the continuous emergence of new viral strains worldwide, it is crucial to maintain active surveillance in the area, contributing to strengthening integrated One Health surveillance efforts.
Assuntos
Infecções por Coronavirus , Vírus da Influenza A , Influenza Aviária , Spheniscidae , Animais , Regiões Antárticas , Conduta Expectante , Influenza Aviária/epidemiologia , Filogenia , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/veterinária , MamíferosRESUMO
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.
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Didelphonema longispiculata (Hill, 1939), a gastric nematode parasite of the black-eared opossum, Didelphis marsupialis Linnaeus, 1758, collected from 2 municipalities of Mato Grosso state, Brazil, in the ecotone region of the Amazon and Cerrado biomes was analyzed with integrative taxonomy using light and scanning electron microscopy (SEM) for morphological studies and sequencing of the 18S small subunit ribosomal RNA for phylogenetic inference through maximum likelihood and Bayesian phylogenetic inference. Here details of the helminth surface, oral aperture with octagonal border, pseudo- and inter-labia, amphids, external cephalic papillae, 2 dorsal and ventral internal plates distally indented, and stoma with strongly chitinized wall are presented. Caudal male papillae, spicules, female vulva, anus, and caudal tip were detailed using SEM. Morphological characteristics and phylogenetic data corroborated the taxonomic placement of the genus Didelphonema within the subfamily Ascaropsinae.
Assuntos
Didelphis , Nematoides , Spiruroidea , Animais , Feminino , Masculino , Didelphis/parasitologia , Filogenia , Teorema de Bayes , Brasil/epidemiologiaRESUMO
We wish to report the occurrence of adult nematodes Ophidascaris arndti (Ascarididae) naturally infecting a new definitive host, the Fonseca's lancehead Bothrops fonsecai (Viperidae), and third-stage larvae of O. arndti parasitizing a new intermediate host, the montane grass mouse Akodon montensis (Cricetidae), both found in the Atlantic Forest of the state of Rio de Janeiro, Brazil. We elucidated the morphological characteristics of both adults and larvae using light and scanning electron microscopy (SEM). Taxonomic affinities between larvae and adult worms were assessed using MT-CO1 gene sequences. Adult and larval gene sequences formed a well-supported clade and had low pairwise p-distances, suggesting that they are conspecific. Our phylogenies also supported the 'arndti', 'filaria', and 'obconica' groups as independent lineages and confirmed the allocation of Ophidascaris within the family Ascarididae, although as an early offshoot. This is the first report of natural infection of this helminth's larvae in a wild intermediate host.
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Cruzia tentaculata is a helminth parasite of marsupials and has a wide geographic distribution from Mexico to Argentina. The aim of this study was to analyse the genetic population structure of this nematode along the Atlantic Forest biome. Cruzia tentaculata specimens were recovered from Didelphis aurita, Didelphis albiventris and Philander quica in 9 localities. Morphological and morphometric data were investigated for phenotypic diversity among localities and hosts using multivariate discriminant analysis of principal components. Phylogenetic relationships of C. tentaculata were determined using maximum likelihood and Bayesian inference. The population structure was analysed by fixation indices, molecular variance analysis, Tajima's D and Fu's Fs neutrality tests, Mantel tests and Bayesian clustering analysis. A higher significant morphometric difference for males was observed between localities. In the haplogroup networks, 2 groups were recovered, separating locations from the north and from the south/southeast. The morphometric variation in C. tentaculata between different localities was compatible with this north and southeast/south pattern, suggesting adaptation to different ecological conditions. Population genetic analyses suggested a pattern of evolutionary processes driven by Pleistocene glacial refugia in the northeast and southeast of the Atlantic Forest based on the distribution of genetic diversity.
Assuntos
Ascaridídios , Didelphis , Marsupiais , Nematoides , Parasitos , Animais , Ascaridídios/anatomia & histologia , Teorema de Bayes , Didelphis/parasitologia , Florestas , Variação Genética , Genética Populacional , Masculino , Filogenia , América do SulRESUMO
BACKGROUND: The population genetics of parasites may be influenced by host specificity, life cycle, host geographical range, evolutionary history, and host population structure. The nematode Aspidodera raillieti infects different marsupial and rodent hosts in the Nearctic and Neotropical regions, implying a gene flow among populations. However, niche diversification of the main hosts of A. raillieti in superimposed areas may provide conditions for population genetic structuring within this parasite species. We examined the genetic structuring of A. raillieti infecting three marsupial species co-occurring along the South and Southeast Brazilian Atlantic Forest, a hotspot of biodiversity. METHODS: We employed morphometric analyses and partial mitochondrial cytochrome c oxidase I gene sequences (MT-CO1) to characterize populations via phylogenetic and phylogeographic analyses. RESULTS: Among 175 A. raillieti specimens recovered from the marsupial hosts Didelphis aurita, D. albiventris, and Philander quica, we identified 99 MT-CO1 haplotypes forming four haplogroups and four clades in networks and phylogenetic trees, respectively. Clades I and II encompassed parasites of D. albiventris from the South region, clade III comprised parasites of D. aurita from the South and Southeast regions, and clade IV encompassed parasites of D. aurita and D. albiventris from the South and Southeast regions and parasites of P. quica from the South region. High genetic differentiation between clades, with a high fixation index and greater genetic variation in the analysis of molecular variance (AMOVA), indicated low gene flow between clades. Haplotypes shared among host species revealed a lack of host specificity. A significant correlation in the Mantel test suggested parasite isolation by distance, while there was no evidence of geographical structure between populations. Negative neutrality test values for clades III and IV suggested recent population expansion. Morphometric differentiation between A. raillieti specimens recovered from different host species, as well as from different localities, was more evident in males. CONCLUSION: The genetic structure of A. raillieti populations in the South and Southeast Atlantic Forest resulted from historical events rather than from current geographical distribution or host specificity. We also demonstrate morphometric variation associated with host species and localities, suggesting phenotypic plasticity to host attributes and to spatial variables.
Assuntos
Ascaridídios , Didelphis , Marsupiais , Parasitos , Animais , Brasil , Didelphis/parasitologia , Florestas , Estruturas Genéticas , Variação Genética , Genética Populacional , Haplótipos , Masculino , Filogenia , FilogeografiaRESUMO
The life cycles of many parasitic nematodes include terrestrial gastropods as intermediate hosts. Over the past few decades, a number of cases of parasitism between molluscs and medically-important nematodes have been reported in Brazil, in particular, those involving the invasive giant African gastropod, Achatina fulica, and zoonoses caused by the nematodes Angiostrongylus cantonensis and Angiostrongylus costaricensis, the etiological agents of neuroangiostrongyliasis and abdominal angiostrongyliasis, respectively. In the present study, larvae found infecting A. fulica, Latipes erinaceus, and Thaumastus taunaisii, from two localities in the Brazilian state of Rio de Janeiro were characterized using light and scanning electron microscopy, and sequences of the 18S rRNA and MT-CO1 genes. Genetic markers allowed to identify the larvae collected in the present study as Cruzia tentaculata, whose adults parasitize didelphid marsupials in the Americas. These findings indicate that both native and non-native gastropods may act as intermediate hosts and represent a previously unnoticed heteroxenous life cycle of C. tentaculata.
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The nematode family Spirocercidae Chitwood and Wehr, 1932, comprises three subfamilies, Spirocercinae Chitwood and Wehr, 1932; Ascaropsinae Alicata and McIntosh, 1933; and Mastophorinae Quentin, 1970, which occur worldwide. Spirocercids infect canids and can cause severe illness. The crab-eating fox, Cerdocyon thous (Linnaeus, 1766), is a canid that inhabits most of South America, including Brazil and is a host for several parasitic worms, in particular, nematodes. However, few reports or genetic data are available on the spirocercids found in this host. In the present study, we describe a new species of Spirobakerus Chabaud and Bain 1981, from the intestine of two crab-eating foxes from two different biomes in Brazil. Spirobakerus sagittalis sp. nov. presents a) unequal spicules, with a long, thin left spicule with a lanceolated shape at the tip; b) a pair of sessile papillae and a median unpaired papillae located anteriorly of the cloaca, and c) a tuft without spines at the tip of the tail in females. The molecular phylogenetic analysis indicated that S. sagittalis sp. nov. is basal to the other species of the subfamily Ascaropsinae, which was not recovered as monophyletic. Our phylogenies also indicated that Spirocercidae is paraphyletic, given that Mastophorinae did not group with Ascaropsinae and Spirocercinae. We provide the first molecular data on the genus Spirobakerus and expand the molecular database of the spirocercids. However, further studies, including the sequences of other spirocercid taxa, are still needed to infer the relationships within this family more accurately.
Assuntos
Canidae/parasitologia , Filogenia , Infecções por Spirurida/veterinária , Spiruroidea/classificação , Animais , Brasil , DNA de Helmintos/genética , Feminino , Masculino , Especificidade da Espécie , Infecções por Spirurida/parasitologia , Spiruroidea/citologia , Spiruroidea/genéticaRESUMO
In semi-arid areas of northeastern Brazil, Chagas disease vectors of Triatoma brasiliensis species complex comprise a monophyletic group of kissing bugs that inhabit rock outcrops. Most of them exhibit allopatric or parapatric distribution; the exception is T. petrocchiae, which is found in cohabitation with T. brasiliensis in rock outcrops. We used vertebrate mitochondrial gene sequencing applied to DNA isolated from bug midgut to identify the insect blood meal sources via BLAST procedure. Fourteen sylvatic insects from four geographic districts in the states of Rio Grande do Norte and Paraíba had their blood meal sources detected. While T. brasiliensis is recorded to be associated mainly (52-71%) with rodents, T. petrocchiae samples were strongly associated (86%) with reptiles of Tropidurus and Hemidactylus genera. We suggest that T. petrocchiae is the single member within this complex to be associated with reptiles, indicating a distinct niche occupation related to the trophic resources.
Assuntos
Interações Hospedeiro-Parasita , Répteis/parasitologia , Triatoma/fisiologia , Animais , Brasil , Doença de Chagas/transmissão , Ecossistema , Insetos Vetores/genética , Roedores/parasitologia , Triatoma/genéticaRESUMO
Tick-borne protozoans of the genus Hepatozoon are obligate hemoparasites that can infect domestic and wild terrestrial vertebrates. Main hepatozoonosis affects canids and involves mainly Hepatozoon canis and Hepatozoon americanum. However, molecular studies revealed the capacity of H. canis to infect a wide range of wild mammals. In July 2018, we conducted an epidemiological survey for tick-borne pathogens in wild hosts, assaying Hepatozoon sp. occurrence in 34 bats captured in different habitats within a conservation unit in the state of Espírito Santo, southeastern Brazil. Blood and spleen tissue DNA samples were submitted to PCR amplifications of Babesia/Theileria and Hepatozoon 18S rRNA gene and 21% (7/34) were positive for Hepatozoon sp. Phylogenetic inferences grouped the obtained sequences from Seba's short-tailed bat (Carollia perspicillata) with the H. canis cluster, and from the great fruit-eating bat (Artibeus lituratus) with rodent-associated Hepatozoon cluster. Further studies are needed to characterize the epidemiological role of Seba's short-tailed bat and the great fruit-eating bat in the wild transmission cycle of these hemoparasites in Brazil.
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Apicomplexa/genética , Quirópteros/parasitologia , Infecções Protozoárias em Animais/parasitologia , Doenças Transmitidas por Carrapatos/veterinária , Animais , Apicomplexa/isolamento & purificação , Brasil/epidemiologia , Filogenia , Infecções Protozoárias em Animais/epidemiologia , Floresta Úmida , Doenças Transmitidas por Carrapatos/epidemiologia , Doenças Transmitidas por Carrapatos/parasitologiaRESUMO
Currently, there are 21 species of Angiostrongylus that parasitize the pulmonary or mesenteric arteries of wild and domestic rodents, felids, canids and human. Species of Angiostrongylus have cosmopolitan distribution covering tropical, subtropical and temperate regions. The procyonid Nasua nasua (coati) is a reservoir host for a wide variety of parasites that may be harmful to its populations or may contain etiological agents with zoonotic potential. In urban areas, coatis are usually found in close association with humans and domestic animals. We morphologically and molecularly characterized a new species of Angiostrongylus found in N. nasua in a protected area within Belo Horizonte, Brazil. The new species of Angiostrongylus differs from other species of the same genus in terms of the length and bifurcation level of the lateral and ventral rays, the length of spicules and female tail morphology. Molecular phylogenetic results based on the mitochondrial cytochrome c oxidase subunit 1 gene suggest that the newly identified species belongs to a genetic lineage that is separate from other species of Angiostrongylus. This new species was collected from the mesenteric arteries of N. nasua. It was named Angiostrongylus minasensis n. sp..
Assuntos
Angiostrongylus , Procyonidae/parasitologia , Angiostrongylus/anatomia & histologia , Angiostrongylus/classificação , Angiostrongylus/genética , Animais , Brasil , Feminino , Masculino , Filogenia , Reação em Cadeia da Polimerase , População UrbanaRESUMO
Abstract Currently, there are 21 species of Angiostrongylus that parasitize the pulmonary or mesenteric arteries of wild and domestic rodents, felids, canids and human. Species of Angiostrongylus have cosmopolitan distribution covering tropical, subtropical and temperate regions. The procyonid Nasua nasua (coati) is a reservoir host for a wide variety of parasites that may be harmful to its populations or may contain etiological agents with zoonotic potential. In urban areas, coatis are usually found in close association with humans and domestic animals. We morphologically and molecularly characterized a new species of Angiostrongylus found in N. nasua in a protected area within Belo Horizonte, Brazil. The new species of Angiostrongylus differs from other species of the same genus in terms of the length and bifurcation level of the lateral and ventral rays, the length of spicules and female tail morphology. Molecular phylogenetic results based on the mitochondrial cytochrome c oxidase subunit 1 gene suggest that the newly identified species belongs to a genetic lineage that is separate from other species of Angiostrongylus. This new species was collected from the mesenteric arteries of N. nasua. It was named Angiostrongylus minasensis n. sp..
Resumo Existem 21 espécies de Angiostrongylus que parasitam as artérias pulmonares ou mesentéricas de roedores silvestres e domésticos, felídeos, canídeos e homem. Espécies de Angiostrongylus têm uma distribuição cosmopolita que abrange regiões tropicais, subtropicais e temperadas. O procionídeo Nasua nasua (quati) é hospedeiro de vários parasitos que podem ser prejudiciais para suas populações ou conter agentes etiológicos com potencial zoonótico. Nas áreas urbanas, os quatis podem ser encontrados em estreita associação com seres humanos e animais domésticos. Nós caracterizamos morfológica e molecularmente uma nova espécie de Angiostrongylus encontrada em N. nasua de uma área protegida na cidade de Belo Horizonte, Brasil. A nova espécie de Angiostrongylus difere de outras espécies do mesmo gênero pelo comprimento e nível de bifurcação dos raios lateral e ventral, o comprimento dos espículos e a morfologia da cauda da fêmea. Resultados moleculares e filogenéticos baseados no gene mitocondrial citocromo c oxidase subunidade 1 indicam que a espécie recém-identificada pertence a uma linhagem genética separada de outras espécies de Angiostrongylus. O presente relato descreve uma nova espécie de Angistrongylus coletada das artérias mesentéricas de N. nasua, denominada Angiostrongylus minasensis n. sp..
Assuntos
Animais , Masculino , Feminino , Procyonidae/parasitologia , Angiostrongylus/anatomia & histologia , Angiostrongylus/classificação , Angiostrongylus/genética , Filogenia , População Urbana , Brasil , Reação em Cadeia da PolimeraseRESUMO
Gigantorhynchus echinodiscus (Diesing, 1851) is a parasite of anteaters in South America. Although described by Diesing in 1851, there is still a lack of taxonomic and phylogenetic information regarding this species. In the present study, we redescribe G. echinodiscus collected from a giant anteater, Myrmecophaga tridactyla Linnaeus, 1758, from the Brazilian Cerrado (Savannah) in the State of São Paulo by light and scanning electron microscopy. In addition, phylogenies were inferred from partial DNA gene sequence of the nuclear large subunit ribosomal RNA gene (28S rRNA). We provide for the first time details of the proboscis with a crown having 18 large hooks and numerous small hooks, a lateral papilla at the base of the proboscis, a ringed pseudo-segmented body, large testes, cemented glands in pairs, and a non-segmented region in the posterior end of the body, which contributed to the diagnosis of the species. Molecular phylogenetic analyses recovered G. echinodiscus forming a well-supported monophyletic group with Mediorhynchus sp., which was congruent with morphological studies that allocate both genera within the family Gigantorhynchidae. In conclusion, the present work adds new morphological and molecular information, emphasizing the importance of adopting integrative taxonomic approaches in studies of Acanthocephala.
RESUMO
The nematode genus Bidigiticauda has 2 species (Bidigiticauda vivipara and Bidigiticauda embryophilum), which are parasites of bats from the Neotropical region. The present paper describes a new species of Bidigiticauda from a male Artibeus planirostris specimen collected in the Pratigi Environmental Protection Area in Bahia state, Brazil. The new species, Bidigiticauda serrafreirei n. sp., differs from B. embryophilum by having longer spicules, rays 5 and 6 arising from a common trunk and bifurcating in its first third, rays 3 and 4 emerging slightly separated from each other, and dorsal rays reaching the margin of the caudal bursa. The new species also differs from B. vivipara by the dorsal ray bifurcating at the extremity of the trunk. A molecular phylogenetic analysis was conducted to determine the evolutionary affinities of Bidigiticauda serrafreirei n. sp. within the Strongylida, which identified a clade that grouped Bidigiticauda with the other members of the Anoplostrongylinae. However, the molineid subfamilies did not group together, indicating that the family Molineidae is polyphyletic. Further analyses, which include additional taxa and genetic markers, should elucidate the complex relationships within the Molineidae, in particular its subfamilies and the evolution of the traits that define these groups.
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Quirópteros/parasitologia , Filogenia , Trichostrongyloidea/classificação , Tricostrongiloidíase/veterinária , Animais , Teorema de Bayes , Brasil , Código de Barras de DNA Taxonômico/veterinária , DNA de Helmintos/química , DNA de Helmintos/isolamento & purificação , Complexo IV da Cadeia de Transporte de Elétrons/genética , Feminino , Florestas , Masculino , Mitocôndrias/enzimologia , RNA Ribossômico 28S/genética , Trichostrongyloidea/anatomia & histologia , Trichostrongyloidea/genética , Trichostrongyloidea/isolamento & purificação , Tricostrongiloidíase/parasitologiaRESUMO
Leptospirosis is an important worldwide zoonosis, caused by a bacterium of the genus Leptospira. For a better understanding of the disease, it is relevant the application of the one health concept. The Atlantic Forest is considered a biodiversity hotspot, with a great endemism of species and despite its importance and proximity to urban areas, the potential role of its fauna as carriers of infectious agents is still poorly understood. Although it is well-known that rats and mice are key reservoirs of leptospires, particularly Rattus norvegicus, wild rodents have also been revealed as reservoirs of leptospiral strains. Thus, the purpose of this study was to investigate the role of the sigmodontine rodents from genera Akodon and Oligoryzomys as pathogenic Leptospira carriers in the Atlantic Forest. We studied 52 Akodon spp. and 15 Oligoryzomys spp. from three areas. Overall 30% were PCR-positive for pathogenic Leptospira, 27% (14/52) Akodon spp. and 40% (6/15) Oligoryzomys spp. DNA sequencing of LipL32 gene confirmed nine species as pathogenic Leptospira. This remarkable incidence of leptospiral carriage within wild genera emphasizes the role of these rodents as carriers of leptospires throughout in this environment.
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Reservatórios de Doenças/veterinária , Leptospira/isolamento & purificação , Leptospirose/veterinária , Doenças dos Roedores/epidemiologia , Animais , Brasil/epidemiologia , Reservatórios de Doenças/microbiologia , Rim/microbiologia , Leptospirose/epidemiologia , Leptospirose/microbiologia , Prevalência , Doenças dos Roedores/microbiologia , SigmodontinaeRESUMO
The echimyid rodents of the genus Thrichomys vary considerably in their behavior and feeding ecology, reflecting their occurrence in environments as different as the Caatinga, Cerrado, Pantanal, and Chaco biomes. While the genus was originally classified as monospecific, a number of Thrichomys species have been recognized in recent decades, based on morphometric, cytogenetic, and molecular analyses. While Thrichomys is well studied, the variation found in its cranial morphology is poorly understood, given the taxonomic and ecological complexities of the genus. Using a geometric morphometric approach, we characterized the differences found in the cranial morphology of four Thrichomys taxonomic units, including three established species, Thrichomys apereoides, Thrichomys fosteri, and Thrichomys laurentius, and one operational taxonomic unit (OTU), Thrichomys aff. laurentius. No significant differences were found among these units in cranium size, but significant variation was found in skull shape. The Procrustes distances provided a quantification of the differences in the shape of the skull, with the largest distances being found between T. aff. laurentius and T. fosteri in the dorsal view, and between T. aff. laurentius and T. apereoides in the ventral view. A Discriminant Function Analysis (DFA) with cross-validation determined that the pairings with the highest correct classification were T. aff. laurentius vs. T. apereoides and T. aff. laurentius vs. T. fosteri, in both views. The principal variation in skull shape was found in the posterior region and the zygomatic arch, which may be related to differences in diet.
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Roedores/anatomia & histologia , Crânio/anatomia & histologia , Animais , EcossistemaRESUMO
Leptospirosis is a common worldwide bacterial zoonosis and has been studied in One Health approaches. Small mammals are described as the most important maintenance reservoirs of several pathogens in nature, including leptospires. The aim of this study was to identify infection by leptospires among small mammals on the Atlantic forest biome and evaluate their potential as carriers of these spirochetes. A total of 153 small mammals belonging to orders Rodentia and Didelphimorphia (distributed on 17 genera and 22 species) were captured. Blood and kidney samples were collected from animals and a conventional PCR targeted on lipL32 gene was conducted on renal tissues. Species identification was performed in eight samples by sequencing of rrs gene. A total of 28% of the animals presented lipL32 PCR-positive, and four pathogenic Leptospira species (L. interrogans, L. borgpetersenii, L. santarosai and L. noguchii) were identified. This study highlights the role of small mammals as carriers of leptospires on the Atlantic Forest representing a potential source of pathogenic Leptospira spp infection for both humans and domestic animals.
Assuntos
Ecossistema , Leptospira/isolamento & purificação , Leptospirose/veterinária , Gambás/microbiologia , Roedores/microbiologia , Animais , Florestas , Humanos , Leptospira/patogenicidade , Leptospirose/epidemiologia , Leptospirose/microbiologia , ZoonosesRESUMO
Nematode parasites of the cardiopulmonary system of livestock and pet animals have been receiving attention due to the pathogenic effects they produce in the course of the infection. However, parasitism in wild animals by metastrongilid nematodes has been neglected, resulting in potential risk to wildlife. Heterostrongylus heterostrongylus is the etiological agent of bronchial pneumonia in the black-eared opossum, Didelphis aurita, a widely distributed marsupial frequently reported to inhabit areas from wild environments to peri-urban spaces. In this study, we reassessed the taxonomy of H. heterostrongylus, describing and comparing morphology of L1 and L3 larvae and adult worms with closely related angiostrongilids, and inferring phylogenetic affinities within the family Angiostrongylidae; we also detailed histopathological reactions under natural infection. Ultrastructural morphology and light microscopy confirmed cephalic structures with well-developed trilobed lips, patterns of caudal bursa rays, spicules shape, terminal anal aperture and presence of the ventral protuberance in L3 larvae, characteristics present for the family Angiostrongylidae. Our molecular phylogenetic analyses, based on the partial small subunit (SSU) 18S rRNA gene, suggested that H. heterostrongylus and Didelphostrongylus hayesi are closely related. Pathological analyses agreed with previous findings, showing that cardiopulmonary parasitism provokes verminous pneumonia and mucous bronchiolitis with hypertrophy of the smooth bronchiolar muscle. These data confirmed that H. heterostrongylus represents a pulmonary pathogen in D. aurita, produces severe pathological effects, and may represent risk to domestic and wild animals.
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Didelphis/parasitologia , Metastrongyloidea/classificação , Infecções por Strongylida/veterinária , Animais , DNA de Helmintos/química , DNA de Helmintos/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Feminino , Pulmão/parasitologia , Pulmão/patologia , Masculino , Metastrongyloidea/genética , Metastrongyloidea/isolamento & purificação , Metastrongyloidea/ultraestrutura , Microscopia Eletrônica de Varredura/veterinária , Filogenia , Análise de Sequência de DNA , América do Sul , Infecções por Strongylida/diagnóstico , Infecções por Strongylida/parasitologiaRESUMO
BACKGROUND: The thin-spined porcupine, also known as the bristle-spined rat, Chaetomys subspinosus (Olfers, 1818), the only member of its genus, figures among Brazilian endangered species. In addition to being threatened, it is poorly known, and even its taxonomic status at the family level has long been controversial. The genus Chaetomys was originally regarded as a porcupine in the family Erethizontidae, but some authors classified it as a spiny-rat in the family Echimyidae. Although the dispute seems to be settled in favor of the erethizontid advocates, further discussion of its affinities should be based on a phylogenetic framework. In the present study, we used nucleotide-sequence data from the complete mitochondrial cytochrome b gene and karyotypic information to address this issue. Our molecular analyses included one individual of Chaetomys subspinosus from the state of Bahia in northeastern Brazil, and other hystricognaths. RESULTS: All topologies recovered in our molecular phylogenetic analyses strongly supported Chaetomys subspinosus as a sister clade of the erethizontids. Cytogenetically, Chaetomys subspinosus showed 2n = 52 and FN = 76. Although the sexual pair could not be identified, we assumed that the X chromosome is biarmed. The karyotype included 13 large to medium metacentric and submetacentric chromosome pairs, one small subtelocentric pair, and 12 small acrocentric pairs. The subtelocentric pair 14 had a terminal secondary constriction in the short arm, corresponding to the nucleolar organizer region (Ag-NOR), similar to the erethizontid Sphiggurus villosus, 2n = 42 and FN = 76, and different from the echimyids, in which the secondary constriction is interstitial. CONCLUSION: Both molecular phylogenies and karyotypical evidence indicated that Chaetomys is closely related to the Erethizontidae rather than to the Echimyidae, although in a basal position relative to the rest of the Erethizontidae. The high levels of molecular and morphological divergence suggest that Chaetomys belongs to an early radiation of the Erethizontidae that may have occurred in the Early Miocene, and should be assigned to its own subfamily, the Chaetomyinae.