Incidence of Echinococcus granulosus in Domestic Dogs in Palestine as Revealed by Copro-PCR

Abstract

Hydatidosis or echinococcosisis considered a neglected zoonotic disease despite its high burden in the livestock industry and the high risk of infection by humans in endemic areas. In a cross-sectional study we estimated the copro-Incidence and also genotyped Echinococcus granulosus isolates from domestic dogs using polymerase chain reaction (PCR). Medical archives in nine major hospitals in Palestine were reviewed to determine incidence of E. granulosus infection detected in humans during surgery. Faecal samples were collected from 93 domestic dogs in three districts with the highest number of human cases: Al-Khalil (Hebron), Tubas and Jenin. Genomic DNA was extracted from dog faecal samples and amplified by PCR targeting the repeat DNA sequence (EgG1 Hae III) followed by sequencing of five positive samples. Genotyping was determined by sequencing and BLAST searching of mitochondrial cytochrome c oxidase subunit (CO1). The incidence of E. granulosus infection detected in humans at surgery was 1.2 per 100,000 in the West Bank and 1.0 per 100,000 in Gaza Strip. Seventeen of 93 domestic dogs (18%) were positive, based upon comparison with the Echinococcus DNA control. The five sequenced samples were confirmed to be E. granulosus. Successfully genotyped sample belonged to E.granulosus sensu stricto (formerly G1-G3 complex, sheep strain). For domestic dogs, age group (13-24 months) and sex were identified as two risk factors for contracting E. granulosus. The study identified the high incidence of E. granulosus sensu stricto in dogs in Palestine.

Fig 1. Distribution of sampled domestic dogs: Map of Palestine West Bank and Gaza showing in brackets the number of human cases reviewed in the medical archives and the three districts from which dog fecal samples were collected.

First number indicates positive results while the second one represents the total number of sampled dogs.

Fig 2. Results of copro-polymerase chain reaction with fecal samples from domestic dogs and controls.

(a) Diagnostic 133 base pair-Hae III target (b) 269 base pair- Hae III target. J-8 and K-8 were shown to be Echinococcus granulosus by sequencing (c) 446 base pair- CO1 target gene for genotyping. Sequencing of Q-8 PCR products revealed a G1 (sheep strain) genotype of Echinococcus granulosus senso stricto.