Genetische Diversität von Dirofilaria repens und D. immitis

Kurzbezeichnung

Genetische Diversität von Dirofilarien

Einrichtung Vetmeduni

Zentrum für Pathobiologie

Art der Forschung

Grundlagenforschung

Forschungsschwerpunkt

Infektionsmedizin

Abstract

Dirofilariasis is an expanding zoonotic disease caused by Dirofilaria spp. nematodes vectored by mosquitoes with dogs as main reservoir hosts. The geographic distribution of these nematodes (and disease) changes dynamically, also because of climate change. Two main parasite species are Dirofilaria repens and Dirofilaria immitis (canine heartworm) and their distribution differs, with heartworm being found in warmer regions than D. repens (Capelli et al. 2018, Alsarraf et al. 2021, Fuehrer et al. 2021). Humans can be infected by the range of Dirofilaria species, however, molecular identification of parasites from human cases is very limited and urgently needed. Despite being cosmopolitan parasites, the knowledge on the genetic diversity of D. repens and D. immitis, occurrence of subspecies/cryptic species or distinct genetic variants is still insufficient (Alsarraf et al. 20023ab).The main aim of the current study is to evaluate the genetic diversity of D. repens and D. immitis from different countries and continents using modern molecular techniques, including metabarcoding and whole genome sequencing. Second main aim is to genotype and identify species and haplotypes of nematodes infecting humans for better understanding of transmission routes.Research hypotheses and detailed aims:H.1. Genetic diversity of Dirofilaria repens and Dirofilaria immitis is related to their geographic originAims: • Metabarcoding: determination of genetic diversity based on several mitochondrial and nuclear markers (COI, NAD, 12S rDNA, ITS)• Mitochondrial genomics (mt genomics): sequencing a mt genome, including Single Long-Range PCR and analysis of mitochondrial protein coding genes (PCGs)• Phylogenetic analyses to decipher evolutionary history of nematodes and recognition of new (sub)species (i.e. cryptic species)• Population genetics and special analyses of genotypes/haplotypes distribution• Comparison of genomes of Dirofilaria spp. from selected regions of the World by Whole Genome Sequencing (WGS) of adult nematodes from distant geographic areas.H.2. Humans can be infected by several species of Dirofilaria and specific haplotypes/variants of D. repens/ D. immitisAims: • Molecular typing of nematodes derived from human cases from different regions of the wWorld• Molecular typing (metabarcoding, mt genomics) of human-originated Dirofilaria for comparisons with animal isolates• WGS of selected nematodes derived from human cases for better recognition of (sub)species- cryptic speciesH.3. Multiple adult worms of the same species infecting an individual canine host can be genetically different (and able to produce genetically different microfilariae)Aim: Genotyping of adult worms infecting the same individual host using droplet digital PCR and other molecular techniques.