Genetic diversity and haplotypes of Echinococcus granulosus isolated from cattle and buffaloes and first report of E. ortleppi (G5) in buffaloes in Pakistan based on mitochondrial cytochrome c oxidase subunit-1 gene (mt-CO1) markers

Cystic echinococcosis (CE) is a parasitic disease that is caused by larval stage of Echinococcus granulosus tapeworm, one of the most important and neglected zoonotic disease. Although the echinococcosis is endemic in the neighboring countries, information regarding circulating genotypes of E. granulosus sensu lato is scarce in Pakistan. Therefore, the main purpose of this report was to contribute in molecular epidemiology and to find genetic variation and haplotypes of E. granulosus s.l. in cattle and buffalo isolates. To identify species circulating in country, parasite samples were collected from different slaughterhouses and butcher shops of two major cities, Rawalpindi and Peshawar located in Punjab and Khyber Pakhtunkhwa (KP) provinces, Pakistan, respectively. A total of 100 CE cyst samples were investigated from buffalo (n = 61), and cattle (n = 39) hosts. After genomic DNA extraction from individual cyst materials, mt-CO1 (875 bp) gene was amplified by PCR. After that, PCR products were electrophoresed on the agarose gel then purified and sequenced using forward primer. The sequences were trimmed (779 bp), aligned and matched with NCBI published sequences. E. granulosus s.s. (G1, G3) (71.4%; n = 20/28) was confirmed as the dominant species in buffalo and cattle. E. ortleppi (G5) (28.6%; n = 8/28) was recorded for the first time in both buffalo and cattle isolates from Rawalpindi. E. granulosus s.l. haplotype network showed single predominant haplotype, which comprised 40% of population. Tajima's D and Fu's Fs were negative and significant for E. ortleppi (G5), suggesting population expansion in Pakistan. Therefore, more studies using isolates of E. granulosus s.l. from various locations and intermediate hosts across Pakistan will add new data on molecular epidemiology and genotyping for effective control strategies of CE in Pakistan.

Global distribution of Echinococcus granulosus genotypes in domestic and wild canids: a systematic review and meta-analysis

The current systematic review and meta-analysis demonstrate the genotypic distribution of canine echinococcosis worldwide. Studies published from the inception until 21 May 2021 were screened, relevant articles were selected and the random-effect model was used to draw forest plots with 95% confidence intervals (CIs). Totally, 44 articles were included, mostly examined dogs (37 records), followed by wolf (8 records), jackal (7 records), fox (3 records), pump fox (3 records) and coyote (1 record). Echinococcus granulosus sensu stricto (G1–G3) and G6/7 cluster of Echinococcus canadensis were the most common genotypes among canids. Most studies were conducted in Asia and Europe with 17 and 15 datasets, respectively. Exclusively, Iran possessed the highest number of studies (10 records). Meta-analysis showed that the pooled molecular prevalence of echinococcosis was 33.82% (95% CI 24.50–43.83%). Also, the highest and lowest prevalence of canine echinococcosis was calculated for South America (66.03%; 95% CI 25.67–95.85%) and Europe (19.01%; 95% CI 9.95–30.16%). Additionally, there were statistically significant differences between the global prevalence of echinococcosis in canines and publication year, continent, country, sample type, host and molecular test. These findings will elevate our knowledge on the poorly known canine echinococcosis worldwide.

Genetic diversity of Echinococcus granulosus sensu stricto in Sardinia (Italy)

Cystic echinococcosis (CE) is a severe parasitic zoonosis caused by the metacestode of the tapeworm Echinococcus granulosus sensu lato (s.l.). The disease has a global distribution representing a significant public health concern. Based on mitochondrial DNA analysis E. granulosus s.l. has been subdivided into five species: E. granulosus sensu stricto (s.s.) (G1, G3 genotype), E. equinus (G4 genotype), E. ortleppi (G5 genotype), E. canadensis (G6-G8, G10 genotype) and E. felidis. E. granulosus s.s., and in particular G1, is the most widespread genotype and the major responsible of human CE cases worldwide. In Italy G1 genotype is higly represented with larger percentages in some hyperendemic areas such as Sardinia. Molecular studies represent a valuable tool to improve our understanding of the E. granulosus epidemiology and CE control strategies. In the present study we investigated genetic variability of E. granulosus s.s. in Sardinia. To this purpose 83 hydatid cysts were collected from different animal species including humans and the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene was partially sequenced (720 bp). Nucleotide sequences from Mediterranean basin were also analyzed for comparison. The phylogenetic network revealed 30 haplotypes grouped around a predominant isolate that had been already reported from other world regions. Haplotype diversity (0.8495 ± 0.0336) and nucleotide diversity (0.003305 ± 0.002014) were similar in Sardinia respect to other Mediterranean countries. Neutrality indices obtained by Tajima's D and Fu's Fs test were significantly negative (p ≤ .01) suggesting expansion of Sardinian population. Low Fixation indices (Fst), ranging from negative values (Algeria, Greece, Spain, other part of Italy) to 0.089 (Albania, France), indicated absence of genetic differentiation, and gene flow between Sardinia and other Mediterranean countries.

Molecular characterization of human Echinococcus isolates and the first report of E. canadensis (G6/G7) and E. multilocularis from the Punjab Province of Pakistan using sequence analysis

BACKGROUND

Echinococcosis is a zoonotic parasitic disease causing serious health problems in both humans and animals in different endemic regions across the world. There are two different forms of human echinococcosis: Cystic Echinococcosis (CE) and Alveolar Echinococcosis (AE). CE is caused by the larval stage of Echinococcus granulosus sensu lato and AE by the larval stage of Echinococcus multilocularis. Geographically, CE is universally distributed, while AE is prevalent in the northern hemisphere. Although the disease is endemic in neighboring countries (China, Iran and India) of Pakistan, there are limited reports from that country. Besides, there are no comprehensive data on the genotyping of Echinococcus species in humans based on sequence analysis. This study aimed to detect the presence of human CE and to identify Echinococcus spp. in human isolates through genetic characterization of hydatid cysts in the Punjab Province of Pakistan.

METHODS

Genetic analysis was performed on 38 human hydatid cyst samples collected from patients with echinococcosis using mitochondrial cytochrome c oxidase subunit 1 (cox1), cytochrome b (cytb) and NADH subunit 1 (nad1). Patient data including age, epidemiological history, sex, and location were obtained from hospital records.

RESULTS

According to the sequence analysis we detected E. granulosus sensu stricto (n = 35), E. canadensis (G6/G7) (n = 2), and E. multilocularis (n = 1). Thus, the majority of the patients (92.1%, 35/38) were infected with E. granulosus s.s. This is the first molecular confirmation of E. canadensis (G6/G7) and E. multilocularis in human subjects from Pakistan.

CONCLUSIONS

These findings suggested that E. granulosus s.s. is the dominant species in humans in Pakistan. In addition, E. canadensis (G6/G7) and E. multilocularis are circulating in the country. Further studies are required to explore the genetic diversity in both humans and livestock.