Population genetic structure and morphological diversity of Cruzia tentaculata (Nematoda: Ascaridida), a parasite of marsupials (Didelphinae), along the Atlantic Forest on the eastern coast of South America.

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.

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.

Population genetic structure and phenotypic diversity of Aspidodera raillieti (Nematoda: Heterakoidea), a parasite of Didelphini marsupials in Brazil's South and Southeast Atlantic Forest.

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.

MORPHOLOGICAL AND GENETIC CHARACTERIZATION OF DIDELPHONEMA LONGISPICULATA (NEMATODA: SPIRUROIDEA) IN THE BLACK-EARED OPOSSUM DIDELPHIS MARSUPIALIS.

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.

New hosts for a snake's helminth: First report of intermediate and definitive hosts naturally infected by Ophidascaris arndti (Ascarididae) in the wild.

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.

Angiostrongylus minasensis n. sp.: new species found parasitizing coatis (Nasua nasua) in an urban protected area in Brazil.

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..

New morphological and genetic data of Gigantorhynchus echinodiscus (Diesing, 1851) (Acanthocephala: Archiacanthocephala) in the giant anteater Myrmecophaga tridactyla Linnaeus, 1758 (Pilosa: Myrmecophagidae).

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.

Pathogenic Leptospira species are widely disseminated among small mammals in Atlantic Forest biome.

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.

Angiostrongylus minasensis n. sp.: new species found parasitizing coatis (Nasua nasua) in an urban protected area in Brazil / Angiostrongylus minasensis n. sp.: nova espécie encontrada parasitando quatis (Nasua nasua) em área de proteção urbana no Brasil

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..