Cystic echinococcosis in Pakistan: Identification and genotyping of Echinococcus Granulosus Sensu Stricto in human cyst isolates

Abstract

Few studies have analysed the current status of cystic echinococcosis (CE) in Pakistan. The study aimed to molecularly characterise Echinococcus infections in humans in Khyber Pakhtunkhwa (KP), Pakistan. A total of 251 formalin-fixed, paraffin-embedded (FFPE) CE cysts, with the clinical data of patients, were collected from four major hospitals in Peshawar, KP, during 2007-2021. The genomic DNAs (gDNA) containing 106 samples were successfully extracted. A multiplex PCR and a real-time PCR assay were performed to detect Echinococcus species. All 106 samples were confirmed as E. granulosus sensu lato and identified as E. granulosus sensu stricto (s.s.). Further analysis by using SNP genotyping showed that the G1 (79.3 %) genotype was the most prevalent compared to G3 (20.7 %). The study pointed out that E. granulosus s.s. G1 genotype is the primary cause of cystic echinococcosis (CE) in Peshawar, highlighting sheep as a major transmission source. The findings underscore the persistent zoonotic risk due to human-livestock interactions over 14 years. The limited access to healthcare facilities for early diagnosis and treatment, poor awareness about the disease among the population, and traditional livestock management practices may be possibly considered as the major factors causing the persistence of human disease in this area. To reduce the disease's impact on human health and economic losses in livestock, further epidemiological studies are essential to support effective control programs against this zoonotic disease in Pakistan.

Keywords: Cystic echinococcosis; E. granulosus sensu stricto; Formalin-fixed; Pakistan; Paraffin-embedded; SNP genotyping; Zoonotic disease.