Historical Aspects of Echinococcosis

Sodium arsenite augments sensitivity of Echinococcus granulosus protoscoleces to albendazole

This study aimed to observe the effects of sodium arsenite (NaAsO₂) on apoptosis of Echinococcus granulosus protoscoleces induced by albendazole (ABZ), and to explore the potential mechanism of NaAsO₂. According to the following final concentrations, the experimental groups were divided into 10 μM NaAsO₂, 20 μM NaAsO₂, 80 μM ABZ, 10 μM NaAsO₂+80 μM ABZ, and 20 μM NaAsO₂+80 μM ABZ. Viability was detected with 0.1% eosin staining. The ultrastructural alterations were visualized by scanning electron microscopy. Caspase-3 activity was assessed with colorimetric assay. Meanwhile, ELISA or WST were applied to detect the activities of antioxidases in NaAsO₂ treatment groups. The maximum protoscolicidal effect was seen with the combination 20 μM NaAsO₂+80 μM ABZ. The ultrastructural damage detected after NaAsO₂+ABZ incubation were greater than those caused by ABZ alone and its primary damage site was the tegument of the parasite. The caspase-3 activity was clearly higher in protoscoleces treated with the combination of NaAsO₂+ABZ than when drugs were used separately. The activities of NQO-1, HO-1, GST, and SOD were significantly lower in protoscoleces incubated with NaAsO₂ than the untreated controls (P < 0.05). According to our results, ABZ could induce protoscoleces apoptosis, and NaAsO₂ could significantly augment sensitivity of protoscoleces to ABZ.

First Case of Human Primary Vertebral Cystic Echinococcosis Due to Echinococcus Ortleppi

Cystic echinococcosis (CE) is a cosmopolitan parasitic zoonosis affecting more than one million people worldwide. In humans, primary bone CE is rare and involvement of E. ortleppi is very uncommon. We report here the first case of primary vertebral cystic echinococcosis due to E. ortleppi in Burgundy, France.

Genetic Diversity in Echinococcus multilocularis From the Plateau Vole and Plateau Pika in Jiuzhi County, Qinghai Province, China

The Qinghai-Tibet Plateau is a highly endemic area of alveolar echinococcosis where a series of intermediate hosts, especially voles and pikas, are infected with Echinococcus multilocularis. The metacestodes of E. multilocularis are fluid-filled, asexually proliferating cysts, and they are mainly found in the host's liver in the form of tumor-like growths. In this study, we investigated the genetic variations of E. multilocularis in four mitochondrial (mt) genes, namely, NADH dehydrogenase subunit 5 (nad5), adenosine triphosphate subunit 6 (atp6), cytochrome c oxidase subunit 1 (cox1), and NADH dehydrogenase subunit 1 (nad1). The complete nad5, atp6, cox1, and nad1 genes were amplified separately from each hydatid cyst isolate using polymerase chain reaction (PCR) and then sequenced. Phylogenetic trees were then generated based on the combined mt genes using MrBayes 3.1.2 and PAUP version 4.0b10. The results showed that thirty of 102 voles and two of 49 pikas were infected with E. multilocularis. The genetic variation distances among all E. multilocularis samples were 0.1–0.4%, 0.2–0.4%, 0.1–0.6%, and 0.1–0.4% for nad5, atp6, nad1, and cox1, respectively. Compared to previous studies of the genetic diversity of E. multilocularis based on the cox1 gene, the genetic distances within the same group were 1.3–1.7% (Mongolia strain), 0.6–0.8% (North American strain), 0.3–0.6% (European strain), and 0.1–0.4% (Asian strain). Based on concatenated sequences of the nad5, atp6, cox1, and nad1 genes all haplotypes were divided into two clusters. In conclusion, the genetic diversity of E. multilocularis based on mt genes on a small local area is at low level but between different regions with long distance and different ecological environment each other, the genetic diversity is at relatively high level; genetic variation is higher in the nad1 gene than that in the other three mt genes. The results on a local scale provide basic information for further study of the molecular epidemiology, genetic differences and control of E. multilocularis in Qinghai Province, China.

Innovative tools for the diagnosis of Echinococcus granulosus in definitive hosts

The aim of this study was to develop and validate an innovative protocol for the diagnosis of Echinococcus granulosus and other Taeniidae in dogs. For this purpose, three experiments were performed, using faecal samples from naturally infected dogs. Firstly, the FLOTAC technique was calibrated with five flotation solutions: saturated sodium chloride (specific gravity, s.g. = 1.20), zinc sulphate (s.g. = 1.35), zinc chloride (s.g. = 1.45), Breza (s.g. = 1.30) and modified Breza (s.g. = 1.40). Then, FLOTAC was compared with four techniques of flotation in centrifuge using: zinc sulphate (s.g. = 1.20), Breza (s.g. = 1.30), modified Breza (s.g. = 1.40), and zinc chloride (s.g. = 1.45). Finally, four different protocols of DNA extraction were compared for Taeniidae identification: QIAamp Tissue Kit and QIAamp Stool from eggs; QIAamp Stool and Wizard Magnetic Purification System for Food from faeces. FLOTAC with zinc sulphate was the most efficient method to detect Taeniidae eggs, showing highest mean of eggs per gram (EPG) of faeces. The QIAamp Stool, using eggs concentrated by FLOTAC, was the best method for DNA extraction. The combination of these protocols provided the highest number of positive samples with PCR, i.e., 47/50 (94.0%). The three negative samples showed a low faecal egg count (2 EPG) below the detection limit (4 EPG) of the protocol. From sequencing of the 47 positive samples: 6 samples were identified as E. granulosus sensu stricto (s.s.), 28 as Taenia hydatigena and 6 as T. pisiformis. A co-infection between different genera of Taeniidae was found in 7 samples.

Efficacy of ursolic acid against Echinococcus granulosus in vitro and in a murine infection model

BACKGROUND

Cystic echinococcosis is a global public health problem; however, the drugs (albendazole and mebendazole) currently recommended by WHO for its treatment, have limited efficacy. Therefore, novel drugs are required to provide more choices for the treatment of this disease.

METHODS

The anthelmintic effects of ursolic acid (UA) were tested on Echinococcus granulosus protoscoleces, germinal cells and metacestodes in vitro. The in vivo efficacy of UA was investigated in mice following secondary infection with E. granulosus. Furthermore, the corresponding ultrastructural damage induced by UA was evaluated by electron microscopy.

RESULTS

In vitro, 45.95 ± 5.30% of protoscoleces were killed by UA at 40 μg/ml, while the growth of more than 90% of germinal cells was inhibited by UA at 10 to 40 μg/ml. The same effect was observed in metacestodes 7 days after treatment with UA at 10, 20 and 40 μg/ml, and more than 50% of metacestodes showed loss of integrity at the end of the experiment. In vivo, metacestode weight was significantly reduced following oral administration of UA at 200 and 100 mg/kg (39.5 and 38.3%, respectively). Additionally, ultrastructural damage, such as alternations in germinal cell morphology and formation of vacuoles and lipid granules were observed in parasites treated with UA in vitro, while detachment of the germinal layer from the laminated layer was also seen in metacestodes in vivo.

CONCLUSIONS

UA was demonstrated to exert parasiticidal activity against E. granulosus in vitro and in vivo, thus implicating UA as a potential anti-echinococcosis agent.

Genetic characterization of Echinococcus granulosus strains isolated from humans based on nad1 and cox1 gene analysis in Isfahan, central Iran

Cystic echinococcosis (CE) is a medically important parasite-caused human disease. Humans may acquire the infection accidentally by ingestion of E. granulosus eggs. The parasite has a broad range of hosts and genotypes, which may affect its aetiological and biological characteristics. The present study aimed to determine the genetic characteristics of human isolates of E. granulosus in Isfahan, Iran. In this cross-sectional study, 50 surgically removed hydatid cysts were collected from hospitalized patients in Al-Zahra Hospital, Isfahan, Iran, over a period of 2 years (2015-2017). DNA was extracted from cyst material, and polymerase chain reactions (PCR) were performed targeting cox1 and nad1 genes. Amplicons were sequenced directly and the resulting sequences were aligned and analysed. Phylogenetic and genetic diversity analyses were also performed. Among the isolates, 43 (86%), 3 (6%) and 4 (8%) out of 50 were E. granulosus (G1), E. granulosus (G3) and E. intermedius (G6), respectively. In total, nine and eight haplotypes were identified by nad1 and cox1 gene analysis, respectively. The haplotype diversity index was higher by cox1 gene analysis (0.547) in G1 strains compared with nad1 (0.433). The G1 genotype was the most predominant isolate from human cases of CE, and the presence of G6 is indicative of an important role of camels in the development of human CE in Isfahan. This is the first report of the G3 genotype causing human CE in Isfahan. Moreover, cox1 gene analysis enables a higher resolution of the genetic diversity of the E. granulosus population compared with nad1 gene analysis.

Prevalence of and risk factors for cystic echinococcosis among herding families in five provinces in western China: a cross-sectional study

Echinococcosis is a severe zoonosis that endangers the health of herdsmen in China’s western provinces. This study aimed to examine the prevalence of this disease and identify potential factors associated with human echinococcosis among herding families.

A cross-sectional study was conducted in five provinces in western China from May 1, 2016 to November 30, 2016, and 1500 herding families participated in the study. A total of 1211 completed questionnaires were analyzed. The prevalence of Cystic echinococcosis (CE) among surveyed herding families was 1.55%. The results of multivariate analysis revealed that the sheep immunization (OR=0.35, 95%CI 0.21-0.58), being concerned about family members echinococcosis (OR=0.49, 95%CI 0.28-0.84) were protective factors, while allowing dogs to roam free (OR=3.17, 95%CI 1.89-5.31), feeding dogs with viscera (OR=3.04, 95%CI 1.83, 5.03), slaughter at home (OR=3.53, 95%CI 2.04-6.12), drinking non-boiled water (OR=2.15, 95%CI 1.28-3.63), eating raw vegetables (OR=1.87, 95%CI 1.13-3.10), not washing hands before meals (OR=3.08, 95%CI 1.68-5.65), and often seeing stray dogs (OR=2.60 95%CI 1.38-4.91) and wild animals (OR=1.92, 95%CI 1.17-3.14) near habitations were more associated with increased risk of infection.

Immunizing sheep, appropriately managing domestic and stray dogs, and improving living environments and behavioral factors may help to reduce the risk of human echinococcosis in western China.