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Taenia hydatigena is a widespread tapeworm of canids (primarily dogs) that causes cysticercosis in ruminants (domestic and wild) and manifests as depression and weakness secondary to various hepatic damages and sometimes mortality in young animals, although, commonly encountered cases are asymptomatic. In most taeniids, genetic polymorphism has been found to impact host preferences, distribution, disease epidemiology and management. Recently, we identified two main mitochondrial lineages of T. hydatigena in China, and here, we examined the mitochondrial nad4‐nad5 genes of T. hydatigena from China, Nigeria, Pakistan and Sudan to assess the intraspecies variation of isolates from these countries and also the distribution of the distinct mitochondrial groups. In addition to China, haplogroup B variant was found in Pakistan, while haplogroup A demonstrated a widespread distribution. We then designed a PCR‐restriction fragment length polymorphism (PCR‐RFLP) assay using XmiI (AccI) and RsaI (AfaI) restriction enzymes to differentiate members of both haplogroups. This result provides more molecular evidence supporting the existence of distinct mitochondrial variants of T. hydatigena. The epidemiological significance of these different mitochondrial groups remains to be explored further. The current PCR‐RFLP assay offers a useful molecular approach for investigating the genetic population structure of T. hydatigena in enzootic regions and in identifying/discriminating the different mitochondrial groups (haplogroups A and B). [ABSTRACT FROM AUTHOR]

Cysticercosis caused by the metacestode larval stage of Taenia hydatigena formerly referred to as Cysticercus tenuicollis is a disease of veterinary importance that constitutes a significant threat to livestock production worldwide, especially in endemic regions due to condemnation of visceral organs and mortality rate of infected young animals. While the genetic diversity among parasites is found to be potentially useful in many areas of research including molecular diagnostics, epidemiology and control, that of T. hydatigena across the globe remains poorly understood. In this study, analysis of the mitochondrial DNA (mtDNA) of adult worms and larval stages of T. hydatigena isolated from dogs, sheep and a wild boar in China showed that the population structure consists of two major haplogroups with very high nucleotide substitutions involving synonymous and non-synonymous changes. Compared with other cestodes such as Echinococcus spp., the genetic variation observed between the haplogroups is sufficient for the assignment of major haplotype or genotype division as both groups showed a total of 166 point-mutation differences between the 12 mitochondrial protein-coding gene sequences. Preliminary analysis of a nuclear protein-coding gene (pepck) did not reveal any peculiar changes between both groups which suggests that these variants may only differ in their mitochondrial makeup. [ABSTRACT FROM AUTHOR]