Genetic diversity and transmission patterns of Echinococcus granulosussensu stricto among domestic ungulates of Sardinia, Italy

Naunain Mehmood,Gaelle Joanny,Antonio Scala,Antonio Varcasia,Claudia Tamponi,Fahad Ahmed,Maria Grazia Cappai,Giorgia Dessì

doi:10.1007/s00436-021-07186-9

Naunain Mehmood, Gaelle Joanny + Show 6 more

Open Access

https://doi.org/10.1007/s00436-021-07186-9

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Abstract

Cystic echinococcosis (CE), a parasitic zoonosis of public health and economic concern, is highly endemic in Sardinia, Italy. The study involved examining the intraspecific variability and demographic structure of Echinococcus granulosussensu stricto (s.s.) in common hosts of this parasite. Molecular surveillance included the fragment amplification of a partial mitochondrial gene, cox1 (750 bp), for a total of 69 isolates derived from sheep (n = 52), cattle (n = 11), pigs (n = 4), and goats (n = 2). It was ascertained that E. granulosus s.s. was the primary agent of infection among these ungulates and G1 genotype was highly prevalent (79.71%). Considerable intraspecific variation was found, revealing the existence of 22 haplotypes with relatively high haplotype (0.8555 ± 0.033) and low nucleotide diversities (0.00281 ± 0.00030). Population demographics indicated an expanding parasitic population signifying negative deviation from neutrality indices. Little genetic differentiation was found between the subpopulations of E. granulosus s.s. in the island. Moreover, the geographic dispersal of genotypes G1 and G3 also indicated similarity between Sardinian and mainland Echinococcus granulosus s.s. populations reaffirming the sympatric occurrence and efficient transmission of G1 and G3 genotypes. Molecular survey of CE has the potential to yield baseline information on the infective genotypes among the intermediate hosts and helps in devising suitable control strategies for curtailing the disease.

Highlights

Cystic echinococcosis (CE) is a globally widespread zoonosis caused by the larval stages of a tapeworm Echinococcus granulosus sensu lato (s.l.)
A maximum likelihood (ML) tree was constructed for phylogenetic resolution of the obtained sequences which clearly positioned the obtained sequences among E. granulosus s.s. (G1 and G3 strains) reference sequences (Fig. 2)
The present study provides a compelling evidence on predominant involvement of E. granulosus s.s. in cystic echinococcosis on Sardinia island

Summary

Introduction

Cystic echinococcosis (CE) is a globally widespread zoonosis caused by the larval stages of a tapeworm Echinococcus granulosus sensu lato (s.l.). Taxonomy of the genus Echinococcus has remained a challenging issue for decades due to striking intraspecific genetic diversity, morphology, life cycle, and host range differences (Romig et al 2015). G3 genotype, which was initially suggested to be buffalo specific (Bowles et al 1992), was subsequently identified in multiple intermediate hosts like sheep, cattle, goats, camels, and wild boars implying the transmission potential of G3 beyond buffalo (Sharbatkhori et al 2011; Laurimäe et al 2019; Mehmood et al 2020). High prevalence of the G3 strain is being recorded in Italy and Sardinia compared to other European and Mediterranean countries indicating its spread beyond the Indian region (Capuano et al 2006; Busi et al 2007; Kinkar et al 2018a)

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