On the geographic genetic variants of the cestode Echinococcus multilocularis with reference to the original descriptions from Bowles et al. (1992) and Bowles and McManus (1993), and their use

Typing of Echinococcus multilocularis by Region-Specific Extraction and Next-Generation Sequencing of the mitogenome

Background

Infection by the fox tapeworm Echinococcus multilocularis may lead to a severe zoonosis in humans, alveolar echinococcosis, which may be fatal if left untreated. Typing is important to understand the epidemiology of this parasite, yet there is limited knowledge on the microdiversity of E. multilocularis on the local scale, since the typing resolution of established methods is restricted.

Methods

The mitogenome of E. multilocularis was used as the target regions to modify, apply and validate the Region-Specific Extraction (RSE) method in combination with Next-Generation Sequencing (NGS). Single Nucleotide Polymorphisms (SNPs) were detected in the mitochondrial DNA (mtDNA) and analysed bioinformatically. To validate the success and the accuracy of the RSE protocol, the mitogenomes of some E. multilocularis isolates were also analysed by the Whole-Genome Sequencing (WGS).

Results

With the chosen combination of methods, the entire mitogenome (~13 kb) of E. multilocularis could be captured and amplified. The read depth (median ≥ 156X) was sufficient to detect existing SNPs. The comparison of mitogenome sequences extracted by RSE with mitogenome sequences obtained by WGS showed that the accuracy of the RSE method was consistently comparable to direct Whole-Genome Sequencing.

Conclusion

The results demonstrate that the RSE method in combination with NGS is suitable to analyse the microdiversity of E. multilocularis at the whole mitogenome level. For the capture and sequencing of large (several kb) genomic regions of E. multilocularis and other applications, this method can be very helpful.

The A2 haplotype of Echinococcus multilocularis is the predominant variant infecting humans and dogs in Yili Prefecture, Xinjiang

Alveolar echinococcosis (AE), caused by Echinococcus multilocularis, is an important zoonotic disease. Yili Prefecture in Xinjiang is endemic for AE, however the molecular variability of E. multilocularis in this region is poorly understood. In this study, 127 samples were used for haplotypes analysis, including 79 tissues from humans, 43 liver tissues from small rodents, and 5 fecal samples from dogs. Genetic variability in E. multilocularis was studied using complete sequences of the mitochondrial (mt) genes of cytochrome b (cob), NADH dehydrogenase subunit 2 (nad2), and cytochrome c oxidase subunit 1 (cox1), using a total of 3558 bp per sample. The Asia haplotype 2 (A2) was the dominant haplotype, with 72.15% (57/79) prevalence in humans, 2.33% (1/43) in small rodents, and 80.00% (4/5) in dogs, followed by A5, the second most common haplotype, which infected 27.91% (12/43) small rodents. Haplotype network analysis showed that all haplotypes clustered together with the Asian group. Pairwise fixation index (FST) values showed lower level of genetic differentiation between different regions within the country. Compared with the sequences of E. multilocularis from North America and Europe, all concatenated sequences isolated from Yili Prefecture were highly differentiated and formed a single population. The A2 haplotype, analyzed using the cob, nad2, and cox1 genes of E. multilocularis, is the predominant variant in humans and dogs in Yili Prefecture.

Clair CC. Age-dependent relationships among diet, body condition, and Echinococcus multilocularis infection in urban coyotes

Urban coyotes (Canis latrans) in North America increasingly exhibit a high prevalence of Echinococcus multilocularis, a cestode of recent and rising public health concern that uses rodents as intermediate hosts and canids as definitive hosts. However, little is known about the factors that drive the high urban prevalence of this parasite. We hypothesized that the diet of urban coyotes may contribute to their higher E. multilocularis infection prevalence via either (a) greater exposure to the parasite from increased rodent consumption or (b) increased susceptibility to infection due to the negative health effects of consuming anthropogenic food. We tested these hypotheses by comparing the presence and intensity of E. multilocularis infection to physiological data (age, sex, body condition, and spleen mass), short-term diet (stomach contents), and long-term diet (δ13C and δ15N stable isotopes) in 112 coyote carcasses collected for reasons other than this study from Edmonton, Alberta and the surrounding area. Overall, the best predictor of infection status in this population was young age, where the likelihood of infection decreased with age in rural coyotes but not urban ones. Neither short- nor long-term measures of diet could predict infection across our entire sample, but we found support for our initial hypotheses in young, urban coyotes: both rodent and anthropogenic food consumption effectively predicted E. multilocularis infection in this population. The effects of these predictors were more variable in rural coyotes and older coyotes. We suggest that limiting coyote access to areas in which anthropogenic food and rodent habitat overlap (e.g., compost piles or garbage sites) may effectively reduce the risk of infection, deposition, and transmission of this emerging zoonotic parasite in urban areas.

MicroRNA profile in immune response of alveolar and cystic echinococcosis patients

It is known that miRNAs are effective in immune response in the diagnosis and treatment of many infectious diseases. However, the miRNAs profile is unknown in Alveolar and Cystic Echinococcosis which can be fatal if left untreated. The miRNAs profile that activates the T and B cells forming the immune system in Alveolar and Cystic Echinococcosis patients was investigated in this study. A total of 50 liver tissue samples were obtained from Alveolar and Cystic Echinococcosis patients in Kilis State Hospital Pathology Laboratory in southeast of Turkey. The circulating cell-free miRNAs were evaluated by a quantitative real-time polymerase chain reaction, statistically calculated within ΔΔCt values and fold changes were evaluated by Welch T test, in which P < .05 was considered to be significant. Twenty-five microRNAs, including let-7a-5p, let-7c, let-7e-5p, miR-15b-5p, miR16, miR-17-5p, miR-23a-5p, miR-24-3p, miR-25-3p, miR-26a-3p, miR-26b-3p, miR-29b-3p, miR-29c-3p, miR-30a-5p, miR-30b-5p, miR-30c-5p, miR-30d-5p, miR-30e-5p, miR-98-5p, miR-101-3p, miR-106b-5p, miR-125b-5p, miR-142-5p, miR-222-3p and miR-223-3p, were found as down-regulated in Alveolar and Cystic Echinococcosis patients than control groups. Twelve miRNAs, including miR-15a-5p, miR-21-5p, miR-27a-3p, miR-29a-3p, miR-146a-5p, miR-181a-5p, miR-181b-5p, miR-181d, miR-181c-5p, miR-195-5p, miR-214-3p and miR-365-3p, were found as up-regulated in Alveolar and Cystic Echinococcosis patients than healthy person. It has been shown that T- and B-cell activities are related in the progressive of both Alveolar and Cystic Echinococcosis in this study. The miRNA panel activated by T and B cells may be important for exploring the mechanisms underlying early development in Alveolar and Cystic Echinococcosis providing novel information that may be used to discover new therapeutics for these diseases.

PET/CT helps to determine treatment duration in patients with resected as well as inoperable alveolar echinococcosis

PURPOSE

The aim of the study was to determine the role of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) at the end of benzimidazole therapy in alveolar echinococcosis.

METHODS

A total of 22 patients undergoing PET/CT at the end of benzimidazole therapy were retrospectively registered. Maximum standardized uptake values (SUV_max) were measured in remaining echinococcus manifestations and compared to normal liver tissue. Long-term clinical follow-up was performed, and recorded data included laboratory parameters, clinical information and imaging.

RESULTS

All patients had no detectable levels of Em-18 antibodies and all echinococcus manifestations were negative on PET/CT, i.e. without focally increased FDG uptake or uptake higher than normal/non-infected liver tissue. All manifestations displayed significantly less FDG-uptake than normal liver tissue, i.e. SUVmax 1.8 (interquartile range (IQR) 1.5-3.5) vs. 3.0 (IQR 2.6-5.7), (p < 0.001). Patients were clinically followed for a median of 9.5 years (IQR 6.5-32.0 years) after their initial diagnosis and for 4.5 years (IQR 3.0-14.0 years) after discontinuation of benzimidazole therapy. No patient showed signs of recurrent infection at the last clinical visit. The 10-year and 20-year freedom from all-cause mortality was 95.0% (95% confidence interval 69.5% - 99.3%), for both. Two events occurred in 292 patient years of follow-up; i.e. two patients (9%) died, one because of pancreatic cancer, the other one because of unknown reasons with no detectable antibody levels.

CONCLUSIONS

Negative FDG-PET/CT results combined with no detectable levels of Em-18 antibodies may allow for the safe discontinuation of benzimidazole therapy in patients with alveolar echinococcosis.