Echinococcus equinus, Williams & Sweatman, 1963

Wassermann, Marion, Aschenborn, Ortwin, Aschenborn, Julia, Mackenstedt, Ute & Romig, Thomas, 2015, A sylvatic lifecycle of Echinococcus equinus in the Etosha National Park, Namibia, International Journal for Parasitology: Parasites and Wildlife 4 (1), pp. 97-103 : 100

3.3. Phylogenetic and haplotype analyses of Echinococcus equinus

Comparative analysis of the E. equinus sequences (nad1 and cox1 genes) showed only a small number of polymorphic sites. Five haplotypes could be identified within the 894 bp long sequence of the complete nad1 gene of the Namibian samples (submitted to GenBank under accession numbers KP161211–KP161216). A sixth haplotype was represented by the horse samples from Italy, whereas the German haplotype (and the sequence of the UK reference) was also present among our Namibian samples. The 1608 bp long cox1 gene showed less variance with only 4 haplotypes (accession numbers KP161207–KP161210), including the Italian and German isolates ( Tables 2 and 3, Fig. 2 ). Cox1 and nad1 haplotypes showed a high degree of correlation, so the combination of both did not result in a drastic increase of haplotype numbers (six variants from Namibia and one additional from each Italy and UK) ( Table 2). The combined (concatenated) haplotype sequences were used for the phylogenetic ML analysis ( Fig. 3 ).

Figures

Fig. 2. Haplotype networks of the complete mitochondrial cox1 (n = 19) and nad1 (n = 27) sequences of E.equinus isolates obtained in this study. Circle sizes are proportional to the number of Namibian zebra isolates, non-Namibian haplotypes are added as dots only (Nam = Namibia, Ger = Germany, Ita = Italy; * = reference isolate, accession number NC020374). For haplotype numbers (I–VI) see Table 2.

Fig. 3. Phylogenetic tree of the genus Echinococcus obtained by maximum likelihood analysis. Phylogram inferred from the concatenated nucleotide sequences of the mitochondrial cox1 and nad1 genes.The scale bar represents the estimated number of nucleotide substitutions per nucleotide site. Nam = Namibia, Ita = Italy, Ger = Germany, UK = United Kingdom. For haplotype letters (A–F) see Table 2. For accession numbers of sequences used for species other than E.equinus see text.