Cystic echinococcosis in Nigeria: first insight into the genotypes of Echinococcus granulosus in animals.

Background: Cystic echinococcosis (CE) is a zoonosis caused by cestodes of Echinococcus granulosus (sensu lato) complex. In Nigeria, reports on the prevalence of CE, although limited, have been found to vary with location and host with higher prevalence and fertility rate observed in camels than other livestock. Until now, information regarding the molecular characteristics, genetic population structure, and genotypes of Echinococcus is lacking. Therefore, this study was aimed at addressing these gaps in knowledge.

Methods: We describe the genetic status of 31 Echinococcus isolates collected from slaughtered livestock (camels, cattle and goats) based on the full-length mitochondrial cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 1 (nad1) genes.

Results: The resulting nucleotide sequences via the NCBI BLAST algorithm and Bayesian phylogeny of cox1 and cox1-nad1 genes using MrBayes v.3.1.2 showed that all isolates were clearly E. canadensis (G6/G7) and were 99-100% identical to previously reported G6/G7 haplotypes across Europe, Asia, North and East Africa.

Conclusions: Although, the G1 genotype is believed to be responsible for the majority of global CE burden, reports from a number of West African countries including Nigeria suggest that E. canadensis G6/G7 genotype could be the major causative agent of CE in the subregion. This study provides for the first time insight into the genetic population structure of Echinococcus species as well as implications for CE control in Nigeria.