Genetic diversity of Echinococcus spp. in wild carnivorous animals in Kazakhstan

Abstract

Background and Aim: The study of Echinococcus infection among farm animals in Kazakhstan was carried out to monitor the invasion among livestock and map the data obtained. Unfortunately, there are only partial data on the study of echinococcosis among wild carnivores in Kazakhstan, which makes it difficult to conduct a comparative analysis of the epidemiological situation among wild animals. The present study aimed to estimate the genetic diversity of Echinococcus spp. (Leuckart, 1863) in Kazakhstan based on sequence analysis of cytochrome c oxidase subunit 1 (cox1) and dehydrogenase subunit 1 (nad1) of worms isolated from wild carnivorous animals wolf (Canis lupus), red fox (Vulpes vulpes) and corsac (Vulpes corsac). Materials and Methods: DNA from parasite tissue was used as a template for the amplification of the two mitochondrial genes cox1 and nad1. Sequencing was performed according to the manual for the Seq Studio Genetic Analyzer. The multiple alignments of obtained sequences were performed using the ClustalW algorithm in Mega (v.11) software. Alignments were exported as a Nexus extension and used as input for TCS v1.21 for the identification of haplotypes. The phylogenetic analysis was constructed according to the neighbor-joining method using Mega (v.11) software. Results: Analysis of the extensiveness of echinococcosis invasion showed that 6.3% were wolves, 18.2% were corsacs, and 85% were foxes. In total, 159 adults of Echinococcus spp. from the three species of animals in different parts of Kazakhstan were analyzed, and 17 individual biological samples were successfully sequenced. Sequence analysis of cox1 and nad1 genes revealed two types of echinococcosis – Echinococcus granulosus in red foxes and wolves, and Echinococcus multilocularis in corsacs. Sequencing of a portion of the mitochondrial genome made it possible to determine seven haplotypes of the pathogen in the studied samples of E. granulosus. Molecular analysis of cox1 and nad1 genes of E. multilocularis revealed three new haplotypes, which have significant variability compared with other studied Asian haplotypes. Conclusion: This study made it possible to fill the gaps in understanding the localization of the foci of the spread of the echinococcosis pathogen among the main wild carnivores and to determine the species reservoir of the pathogen in the greater territory of Kazakhstan.