Dr. med. vet. Pavlo Maksimov (Greifswald / DE), Pablo Angulo Lara (Madrid / ES), Lokman Galal (Limoges / FR), Prof., Dr. Rafael Calero-Bernal (Madrid / ES), Mercedes Fernández-Escobar (Madrid / ES), Prof., Dr. Aurélien Mercier (Limoges / FR), Dr. Hernan Lorenzi (Bethesda, MD / US; Rockville, MD / US), Maike Joeres (Greifswald / DE), Prof., Dr. Bretislav Koudela (Brno / CZ), Prof., Dr. Radu Blaga (Maisons-Alfort / FR), Dr. Majda Globokar Vrhovec (Kornwestheim / DE), Dr. Kaya Stollberg (Berlin / DE), Dr. Nadja Bier (Berlin / DE), Prof., Dr. Smaro Sotiraki (Thessaloniki / GR), Dr. Jacek Sroka (Pulawy / PL), Dr. Weronika Piotrowska (Pulawy / PL), Prof., Dr. Petr Kodym (Prague / CZ), Dr. Walter Basso (Bern / CH), Prof. Dr. Franz J. Conraths (Greifswald / DE), Prof., Dr. Marie-Laure Dardé (Limoges / FR), Dr. Furio Spano (Rome / IT), Dr. Paolo Vatta (Rome / IT), Prof., Dr. Simone Caccio (Rome / IT), Dr. Pikka Jokelainen (Copenhagen / DK), Prof., Dr. Luis Miguel Ortega-Mora (Madrid / ES), Dr. Gereon Schares (Greifswald / DE)
Abstract text
Introduction:
Toxoplasma gondii is a highly prevalent protozoan parasite that globally infects a broad range of animals, including humans. A better knowledge of the genetic diversity and population structure of T. gondii may help to understand transmission routes and sources of infection for livestock and humans.
Objectives:
There is limited data on genome-wide comparisons of field isolates belonging to the same T. gondii clonal lineage. Therefore, the aim of the present study was to assess genome-wide genetic diversity among T. gondii Type II isolates from Europe, where this clonal lineage is predominant.
Materials and Methods:
The genomes of 75 European T. gondii Type II isolates, were assessed by whole genome sequencing (WGS) and compared to the Type II reference strain ME49.
Results:
At least 95% of the reads for each T. gondii European field isolate mapped to the reference whole genome sequence. Mapped reads covered over 99% of the reference genome with a read depth of > 70 per base. The total number of SNPs relative to reference varied between ~4000 and ~12000. Affinity propagation clustering (APC) analysis revealed 5 subpopulations among 75 T. gondii Type II isolates from Europe, whereas ADMIXTURE analysis showed the presence of 3 subpopulations. Subpopulations identified by both, APC and ADMIXTURE corresponded to each other. Interestingly, subpopulations were not equally distributed all over Europe but showed clustering in particular European regions.
Conclusion:
The European T. gondii Type II population is genetically more diverse than expected. Based on our experiences, WGS may be useful to better understand the molecular epidemiology of the parasite in Europe, to trace infection sources in outbreaks and to detect the introduction of exotic or the emergence of recombinant strains.
Funding
This work was done as part of TOXOSOURCES project, supported by funding from the
European Union"s Horizon 2020 Research and Innovation programme under grant agreement No
773830: One Health European Joint Programme.