Cystic echinococcosis in Poland: genetic variability and the first record of Echinococcus granulosus sensu stricto (G1 genotype) in the country

Species and genotypes belonging to Echinococcus granulosus sensu lato complex causing human cystic echinococcosis in Europe (2000-2021): a systematic review

BACKGROUND

This study aimed to fill a gap of knowledge by providing a quantitative measure of molecularly identified species and genotypes belonging to Echinococcus granulosus sensu lato (s.l.) causing human cystic echinococcosis (CE) in Europe during the period 2000-2021. As these species and genotypes are characterized by genetic, animal host and geographical differences, studying the E. granulosus s.l. complex is epidemiologically relevant.

METHODS

A systematic review (SR) was conducted on the basis of both scientific and grey literature considering primary studies between 2000 and 2021 in four databases. From a total of 1643 scientific papers, 51 records were included in the SR. The main inclusion criterion for this study was the molecular confirmation of E. granulosus s.l. at the genotype/species level as a causative agent of human CE cases in selected European countries.

RESULTS

Relevant data were obtained from 29 out of 39 eligible European countries. This SR identified 599 human molecularly confirmed echinococcal cysts: 460 (76.8%) identified as E. granulosus sensu stricto (s.s.), 130 (21.7%) as E. canadensis cluster (G6/7 and G10), 7 (1.2%) as E. ortleppi (G5), and 2 as E. vogeli (0.3%). Three geographical hotspots of human CE caused by different species of the E. granulosus s.l. complex were identified: (1) E. granulosus s.s. in Southern and South-eastern Europe (European-Mediterranean and Balkan countries); (2) E. canadensis (G6/7) in Central and Eastern Europe; (3) E. ortleppi in Central and Western Europe. This SR also identified data gaps that prevented a better definition of the geographical distribution of the Echinococcus granulosus s.l. species complex in Europe: western Balkan countries, part of Central Europe, and Baltic countries.

CONCLUSIONS

These results mandate longitudinal, multi-centre, intersectoral and transdisciplinary studies which consider both molecular and clinical epidemiology in animals and humans. Such studies would be valuable for a better understanding of the transmission of the E. granulosus s.l. species complex and their potential clinical impact on humans.

Molecular Study of Echinococcus granulosus Cestodes in Ukraine and the First Genetic Identification of Echinococcus granulosus Sensu Stricto (G1 Genotype) in the Country

INTRODUCTION

Cystic echinococcosis is a globally distributed zoonotic disease of great medical and veterinary importance, which is caused by the cestode Echinococcus granulosus sensu lato. In Ukraine, two areas of the prominent circulation of the parasite are established, the southern steppe zone with sheep as the main transmitter, and the northern forest-steppe zone and Polissia, where pigs are mainly responsible for maintaining the E. granulosus transmission.

METHODS

Given that only a few studies have so far addressed the genetic diversity of the parasite in Ukraine, we have sequenced partial mitochondrial genes of cytochrome c oxidase 1 (789 bp), NADH dehydrogenase 1 (602 bp) and 12S rRNA (333-334 bp) in pig metacestodes from the Sumy region (farms close to Sumy, northeastern Ukraine) and the Kyiv region (a farm in Bila Tserkva, central Ukraine).

RESULTS

Four isolates from four pigs in the Sumy region were identified as E. canadensis (G7 genotype), the major E. granulosus s.l. species circulating in Eastern Europe, including the three microvariants (G7A, G7B, G7C). Three isolates from the two pigs in the Kyiv region were classified as E. granulosus s.s. (G1 genotype), including one microvariant (G1A).

CONCLUSION

To our knowledge, this is the first genetic record of E. granulosus s.s. with the presumed highest infectivity and virulence among the E. granulosus s.l. species in Ukraine. The finding has implications for public health as local control programmes should take into consideration different development rate of this parasite in dogs and the greater risk of the species for human infection.

Echinococcus granulosus sensu lato Genotypes in Different Hosts Worldwide: A Systematic Review

INTRODUCTION

The aim of this study was to develop a synthesis of the evidence available regarding verified E. granulosus sensu lato (s.l.) genotypes in different species worldwide.

MATERIAL AND METHODS

A systematic review was performed including studies concerning genotypes of E. granulosus s.l. without language or genotyped method restriction, published between 1990 and 2020. A systematic search was carried out in Trip Database, BIREME, SciELO, LILACS, IBECS, PAHO-WHO, EMBASE, PubMed, Scopus, and WoS. Variables of interest were year of publication, country, number of samples, and hosts; genotypes, molecular marker, haplotypes and molecular biology techniques used. Descriptive statistics were applied.

RESULTS

2411 articles were analyzed, however 135 met the selection criteria, representing 8643 liver and lung samples. Of the samples selected 24% were human, the remaining samples pertained to non-human animal hosts; cattle and sheep prevailed with 28.6% and 26.6% of the studied samples, respectively. The reported evidence is mainly from Iran, Turkey, Argentina, China and Chile; with 50, 11, 6, 6 and 5 studies, respectively, published between 1992 and 2020 [most frequently during 2015-2020 (76/135 studies; 56.3%)]. The mitochondrial gene cox1 was generally sequenced and informative (91.8%). Genotypes most frequently identified were E. granulosus sensu stricto (s.s.) (83.2%).

CONCLUSIONS

Based on this overall evidence, it can be concluded that publications related to genotypes of E. granulosus s.l. are heterogeneous. E. granulosus ss accounts for the vast majority of the global burden of E. granulosus s.l. worldwide. Further studies including larger number of cases and adequate internal validity are required to specify the distribution of genotypes in various host species.

TRIAL REGISTRATION

PROSPERO CRD42018099827.

Genotypes of Echinococcus Species from Cattle in Tanzania

Cystic echinococcosis is a zoonotic parasitic disease caused by Echinococcus species. Tanzania is one of the endemic countries with cystic echinococcosis. This study focussed on identifying genotypes of Echinococcus spp. in Tanzania. We collected 7 cysts from cattle in Mwanza municipal (n=4) and Loliondo district (n=3). The cysts from Mwanza were all E. ortleppi and fertile. In contrast, the cysts from Loliondo were all E. granulosus sensu stricto and sterile. Two from the 4 cysts were a new haplotype of E. ortleppi (G5). These results can improve the preventive and control programs for humans and livestock in Tanzania. To our knowledge, this study is considered the first to identify the genotype and haplotype of Echinococcus spp. in Tanzania.

The Molecular Epidemiology of Cystic and Alveolar Echinococcosis in Southeast Turkey

Background

The migration of humans and climatic and environmental changes cause the emergence of infectious diseases. This study aimed to investigate the changes in the molecular epidemiology of the echinococcosis in the southeast region of Turkey after migrations.

Methods

Overall, 159 tissues samples were taken from suspected cases of echinococcosis at the Kilis State Hospital in the southeast region of Turkey. All of the tissues samples were analyzed using histopathology methods, PCR, Real-time PCR methods, DNA sequencing, and phylogenetic analyses in laboratories.

Results

The positivity values of the histopathology, the polymerase chain reaction, and the Real-time PCR methods were found to be 14.5% (23/159),15.7% (25/159), and 16.9% (27/159), respectively. 32.0 % (8/25) E. multilocularis of Echinococcus isolates and 68% (17/25) E. granulosus of Echinococcus isolates were identified using PCR methods. 58.8% (10/17) of the E. granulosus isolates were found to be Genotype 1% and 41.2% (7/17) E. granulosus isolates were found to be Genotype 3.

Conclusion

Molecular methods play an important role in the epidemiology, treatment, and diagnosis of diseases. Increasing immigration in a geographical area may create social, economic, and health problems in that area. For this reason, epidemiological studies of infectious diseases should be updated in areas with immigration.

Factors influencing the spatial distribution of cystic echinococcosis in Tibet, China

Cystic echinococcosis (CE), which is caused by Echinococcus granulosus, is a worldwide helminthozoonosis that is highly endemic in the Tibet Autonomous Region of China and has important public health and economic impacts. However, the spatial epidemiological characteristics of CE in Tibet are still unclear. Based on recorded human CE cases and the use of a geographic information system, the spatial distribution patterns of CE prevalence at three different scales were analyzed. In addition, a spatial agglomeration map of CE prevalence was generated based on cold/hot spot analysis. By combining maps of environmental and biological covariates with information about known human CE cases, the links between CE prevalence and relevant covariates were explored, revealing that the annual average precipitation, elevation, water accessibility and animal population (dog and yak) were associated with the prevalence of CE at the significance level of P < 0.05. Our results provide a novel insight and better understanding of the current situation of and the factors influencing CE in Tibet, which can help public health authorities develop disease prevention and control strategies.

A Pilot Comparative Study Between Serological and Genetic Investigations in Relationship to Clinical Outcomes on Patients with Cystic Echinococcosis

The aim of this study was to investigate whether Enzyme-Linked Immunosorbent Assays (ELISA) and Western Blotting (WB) methods could contribute to the assessment of clinical outcomes in genotype-defined cystic echinococcosis (CE) patients. Twenty-nine human isolates and blood samples have been taken from patients who underwent surgery or percutaneous aspiration (PAIR) for therapeutic purposes at Ege University and Manisa Celal Bayar University Hospitals. All sera of patients were screened for the presence of E. granulosus IgG antibodies using in-house approved ELISA and WB methods. According to the ELISA results, five patients had high, thirteen patients had medium and eight patients had low specific antibody level response which ranged 1/640 -1/5000. Despite confirmed WB positivity three patients were found to be negative by ELISA. Immunoblot analysis of EgAg showed many protein bands with size of 8, 12, 20, 22, 24, 36, 75 and 90 kDa. Among of them, 8 - 12 kDa bands (90 %), 20 - 22 kDa and 36 kDa bands presented strong reactivity against human serum specimens. No serum samples from healthy control reacted with EgAg. Phylogenetic analysis of resulting COX1 and NAD1sequences has revealed that all patients in our study were infected with the E. granulosus G1-G3 genotype. There was no consistent correlation between results of ELISA and WB, the number or size of cysts and genotype. Our study brings a unique contribution in terms of relationship between serological investigation, disease genotypes and clinical outcomes.

Differentiation between hepatic cystic echinococcosis types 1 and simple hepatic cysts: A retrospective analysis

This study aims to evaluate the clinic value of ultrasound, computed tomography (CT) and serological testing in the differentiation between hepatic Cystic Echinococcosis (CE) types 1 and simple hepatic cysts.Totally 50 patients with CE Types 1 and 50 patients with simple hepatic cysts were included. All patients examined by ultrasound, CT and serological testing respectively. The receiver operating characteristic (ROC) curve of diagnosis methods was drawn and their sensitivity, specificity, Youden index, positive likelihood ratio, negative likelihood ratio, positive predictive value and negative predictive value were compared. Pathology result was used as golden standard.The area under ROC curve of ultrasound was 0.97 and of CT and serological testing was 0.79 and 0.71 respectively. The sensitivity of ultrasound in the diagnosis of CE Types 1 was 96.00%, specificity was 98.00%, the positive likelihood ratio was 48.00, and negative likelihood ratio was 0.04. Disease prevalence was 50%, positive predictive value was 97.96%, and negative predictive value was 96.08%. The sensitivity of CT was 80.00%, specificity was 62.00%, positive likelihood ratio was 2.11, and negative likelihood ratio was 0.32. Disease prevalence was 50%, positive predictive value was 67.80%, and negative predictive value was 75.61%. The sensitivity of immunological test was 86.00%, specificity was 72.00%, positive likelihood ratio was 3.07, and negative likelihood ratio was 0.19. Disease prevalence was 50%, positive predictive value was 75.44%, and negative predictive value was 83.72%. Combined ultrasound and immunological test, the sensitivity and the specificity was 82% and 100% respectively. Combined CT and immunological test, the sensitivity the specificity was 70% and 82% respectively.In the differentiate diagnosis of CE Types 1 and simple hepatic cyst, ultrasound is better than CT with high sensitivity and specificity, therefore recommended. Immunological examination is an important complement to the imaging examination.