Genome sequence of the cardiopulmonary canid nematode Angiostrongylus vasorum reveals species-specific genes with potential involvement in coagulopathy

Seek, and you will find: Cryptic diversity of the cardiopulmonary nematode Angiostrongylus vasorum in the Americas

Angiostrongylus vasorum is a metastrongylid parasite infecting wild canids and domestic dogs. Its patchy distribution, high pathogenicity and taxonomical classification makes the evolutionary history of A. vasorum intriguing and important to study. First larval stages of A. vasorum were recovered from feces of two grey foxes, Urocyon cinereoargenteus, from Costa Rica. Sequencing and phylogenetic and haplotypic analyses of the ITS2, 18S and cytochrome oxidase subunit 1 (cox1) fragments were performed. Then p- and Nei´s genetic distance, nucleotide substitution rates and species delimitation analyses were conducted with cox1 data of the specimens collected herein and other Angiostrongylus spp. Cophylogenetic congruence and coevolutionary events of Angiostrongylus spp. and their hosts were evaluated using patristic and phenetic distances and maximum parsimony reconciliations. Specimens from Costa Rica clustered in a separate branch from European and Brazilian A. vasorum sequences in the phylogenetic and haplotype network analyses using the ITS2 and cox1 data. In addition, cox1 p-distance of the sequences derived from Costa Rica were up to 8.6 % different to the ones from Europe and Brazil, a finding mirrored in Nei´s genetic distance PCoA. Species delimitation analysis supported a separate group with the sequences from Costa Rica, suggesting that these worms may represent cryptic variants of A. vasorum, a new undescribed taxon or Angiocaulus raillieti, a synonym species of A. vasorum described in Brazil. Moreover, nucleotide substitution rates in A. vasorum were up to six times higher than in the congener Angiostrongylus cantonensis. This finding and the long time elapsed since the last common ancestor between both species may explain the larger diversity in A. vasorum. Finally, cophylogenetic congruence was observed between Angiostrongylus spp. and their hosts, with cospeciation events occurring at deeper taxonomic branching of host order. Altogether, our data suggest that the diversity of the genus Angiostrongylus is larger than expected, since additional species may be circulating in wild canids from the Americas.

Hookworm genomics: dusk or dawn?

Hookworms are parasites, closely related to the model nematode Caenorhabditis elegans, that are a major economic and health burden worldwide. Primarily three hookworm species (Necator americanus, Ancylostoma duodenale, and Ancylostoma ceylanicum) infect humans. Another 100 hookworm species from 19 genera infect primates, ruminants, and carnivores. Genetic data exist for only seven of these species. Genome sequences are available from only four of these species in two genera, leaving 96 others (particularly those parasitizing wildlife) without any genomic data. The most recent hookworm genomes were published 5 years ago, leaving the field in a dusk. However, assembling genomes from single hookworms may bring a new dawn. Here we summarize advances, challenges, and opportunities for studying these neglected but important parasitic nematodes.

Microbiome dataset of the cardiopulmonary nematode Angiostrongylus vasorum

Angiostrongylus vasorum is an emerging parasitic nematode of dogs, red foxes, and other wild canids. The severity of infection in dogs ranges from subclinical to fatal cardiopulmonary and bleeding disorders collectively known as canine angiostrongylosis. A symbiotic relationship between microorganisms such as bacteria and their eukaryotic hosts is commonly observed in nature. The mutualistic role of bacteria has been documented in plant-parasitic nematodes, gastrointestinal nematodes, and filarial nematodes. The importance of the bacteria for the survival of these parasites has been demonstrated with antibiotic treatments. To characterize associated bacteria of adult A. vasorum parasites, 36 individual worm samples were used. The worms were extracted from foxes hunted either in the city or in the rural regions within the Canton of Zurich, Switzerland. DNA was isolated and the V3/V4 hypervariable region of the bacterial 16S rRNA gene was amplified. Sequenced Illumina MiSeq reads were analysed using QIIME2. The data were used to profile the abundance and diversity of microbial communities in worms originating from either rural or urban foxes.