First report of Echinococcus granulosus G8 in Eurasia and a reappraisal of the phylogenetic relationships of ‘genotypes’ G5-G10

Abstract

In this study, we investigated the presence of the larval stage of the tapeworm Echinococcus granulosus in wild ungulates in Estonia, genetically characterized E. granulosus isolates using mitochondrial gene sequences and used the sequence data, together with those available in a public database, to infer the phylogenic relationships of E. granulosus 'genotypes' G5-G10. While 0.8% of the 2038 moose (Alces alces) examined were found to be infected with E. granulosus, the parasite was not detected in other wild ungulates, such as roe deer (Capreolus capreolus: 1044 specimens examined) and wild boar (Sus scrofa: 442 specimens). Genetic analyses of concatenated atp6, nad1 and cox1 gene (1028 bp) sequences revealed that 2 novel E. granulosus haplotypes, namely E8 (11 samples: 69%) and E10 (5 samples: 31%), grouped with E. granulosus G8 and G10, respectively, are present in Estonia. This is the first record of an E. granulosus G8 in Eurasia. Phylogenetic analyses, using 4 different methods, demonstrated with considerable statistical support that E. granulosus G6/7 forms a subgroup together with G10, whereas G8 is a sister taxon to G6/7-G10.

Global Distribution of Alveolar and Cystic Echinococcosis

“…Later, economic and social changes caused a decrease in the numbers of family farms, (Moks et al, 2008). Of these, 11 belonged to genotype G8 and 5 to genotype G10.…”

Genetic Characterization of Echinococcus granulosus from a Large Number of Formalin-Fixed, Paraffin-Embedded Tissue Samples of Human Isolates in Iran

“…Consequently, a taxonomic reappraisal relying mainly on mitochondrial data has proposed that E. granulosus species splits to four valid species including: 1) E. granulosus sensu stricto (G1-G3 complex), 2) E. equines (G4), 3) E. ortleppi (G5), and 4) E. canadensis (G6-G10). 17,21,22 Moreover, E. felidis (lion strain) is closely related to E. granulosus sensu stricto and is placed within the E. granulosus complex. 23 Recently, based on more complex data containing nuclear sequences and the epidemiological aspects, it was recommended that genotypes G6-G10 should be broken into two distinct species including E. canadensis (G8 and G10 genotypes) and E. intermedius (G6/ G7 genotypes).…”

Biology and Systematics of Echinococcus

“…These informal groupings were retained for many years but with the advent of molecular characterization they were shown to be genetically distinct (Thompson and McManus, 2001). PCR-based techniques using a variety of genetic loci, and sequencing of nuclear and mitochondrial DNA, coupled with molecular epidemiological studies in endemic areas, confirmed the genetic and morphological distinctness of the host-adapted strains and revealed phylogenetic relationships which support a robust, meaningful taxonomy based on a previously documented nomenclature (Table 2; Bowles et al, 1994;Cruz-Reyes et al, 2007;Harandi et al, 2002;Huttner et al, 2009;Jenkins et al, 2005Lavikainen et al, 2003Moks et al, 2008;Nakao et al, 2013;Pednekar et al, 2009;Romig et al, 2006Romig et al, , 2015Saarma et al, 2009;Thompson et al, 1995Thompson et al, , 2006Thompson, 2001Thompson, , 2008Thompson and McManus, 2002;Tigre et al, 2016). Interestingly, the nomenclature used for these 'species' conforms to that proposed by observational parasitologists in the 1920se60s, before molecular tools were available to confirm and support their morphological descriptions and epidemiological observations Thompson and McManus, 2002;Thompson, 2008).…”