Control of cystic echinococcosis/hydatidosis: 1863-2002

A Ferritin-Based Eg95 Nanoparticle Vaccine Adjuvanted with pCpG Eliciting Robust Immune Responses Against Cystic Echinococcosis in Mice Model

Introduction

Cystic echinococcosis (CE), a chronic disabling parasitic zoonosis, poses a great threat to public health and livestock production and causes huge economic losses globally. The commercial Quil-A-adjuvanted Eg95 vaccine was empirically effective for CE control; however, it is expensive and has side effects and insufficient immunity.

Purpose

This study aimed to employ a novel adjuvant consisting of a delivery system and an immune potentiator and assess its adjuvanticity to Eg95 antigen, thereby developing a safe and cost-effective novel vaccine against the disease.

Methods

A ferritin-based Eg95 nanoparticle antigen was prepared and then mixed with a plasmid containing the TLR9 agonist CpG to formulate a novel nanovaccine. The safety and efficacy of the vaccine were evaluated in vitro and in vivo.

Results

The nanovaccine induced potent and enduring Eg95-specific humoral and cellular immune responses, as well as protective immunity-associated Th1 polarization supported by the higher ratios of IgG2a/IgG1 and IFN-γ/IL-4. Meanwhile, this nanovaccines exhibited favorable safety and economic profiles.

Conclusion

Our data demonstrated that the ferritin-CpG hybrid is a promising combination adjuvant to upgrade the traditional Quil-A and this combination adjuvant-based nanovaccine presents good potential as an alternative to the commercial one for practical CE control.

A scoping review on control strategies for Echinococcus granulosus sensu lato

Background

Cystic echinococcosis (CE) is a widespread neglected zoonotic disease caused by Echinococcus granulosus sensu lato (EG) with a global burden of control in the billions of dollars. E. granulosus' life cycle involves definitive, intermediate, and humans as dead-end hosts. Echinococcosis control programs use strategies that focus on any of these hosts. We aimed to provide a comprehensive and up-to-date overview of the EG control interventions worldwide.

Methods

We conducted a scoping review by mapping all studies on interventions for EG control following the Arksey and O'Malley Framework. We screened identified articles, and charted and coded selected papers. We classified the data based on target host, type of study, and control mechanism. We described the efficacy or safety outcomes, and the associated barriers/facilitators for the intervention. Critical appraisal was conducted.

Results

From 7,853 screened studies, we analyzed 45: seven centered on human interventions, 21 on animals, and 17 on both. Studies on humans focused on educational strategies and human CE monitoring. The studies on animals were field trials and most were based on Praziquantel (PZQ) for dogs. Studies focused on both animals and humans had, in general, more participants, lasted longer, and covered larger geographical areas. Overall, the quality of studies was moderate to low.

Conclusions

Available evidence suggests that long-term interventions aimed at both animals and humans can achieve significant reduction in EG transmission, particularly when PZQ treatment for dogs is included. Higher quality evidence, standardization of methodologies, and better reporting on post-intervention outcomes are necessary for drawing stronger conclusions. Further evidence is needed to assess the sustainability and scalability of control measures. Nonetheless, an integrative One Health approach is essential for overcoming the multiple challenges associated with sustaining long-term control efforts for Echinococcosis.

Funding

RCN was supported by the National Institute of Allergy and Infectious Diseases (grant nos. K01AI139284 and R01AI168291). LOC, JAB, and RCN were supported by the Fogarty International Center (grant no. D43TW012741). TAD, CG and JAB were supported by the Fogarty International Center (grant no. D43TW001140).

Author Summary

Cystic echinococcosis is a disease caused by the parasite Echinococcus granulosus sensu lato . This parasite can be found in specific areas on all continents, especially in poverty-stricken regions, increasing costs and losses. Some countries have achieved control, but most are still in the process. Our review provides a clear picture of what we currently know about these control strategies and points out where more research is needed. It highlights how the findings can improve control practices by showing what works best and address practical challenges. The review also identifies gaps in current knowledge and suggests that comparing different control methods could help find the most effective and cost-efficient solutions. Key areas needing attention include increasing support and funding for echinococcosis, as the disease is often overlooked. More research from different fields is needed to better understand and manage the disease's complexities. Better and ongoing surveillance is crucial for maintaining effective control strategies. Finally, comprehensive reviews that bring together findings from different studies are needed to identify what works best and improve and combine future control efforts.

Echinococcus granulosus sensu lato control measures: a specific focus on vaccines for both definitive and intermediate hosts

Echinococcosis, a neglected zoonotic disease caused by Echinococcus tapeworms, presents significant public health challenges worldwide. Cystic and alveolar echinococcosis has substantial health and economic impacts, necessitating effective prevention and control strategies. The present review provides a framework to expand our knowledge regarding key components of echinococcosis prevention and control, including phases, options, targets and available tools as well as current gaps and challenges in the field. Furthermore, we discuss the progress made in developing vaccines for the intermediate and definitive hosts and review the limitations and obstacles in vaccine development for definitive hosts. Abundant information is available on various aspects of the Echinococcus vaccine in sheep. Livestock vaccination effectively reduces Echinococcus transmission to sheep, offering a feasible control measure in intermediate hosts. However, vaccine development for the definitive host, i.e. dogs, exhibits significant challenges. Information gaps regarding the immune-mediated protective responses in dogs, repeatability of results, factors influencing the immune response, reinfection resistance, potential age-related decreases in worm burden and factors associated with the antifecundity effect are key challenges that should be addressed in canine vaccine development, and research collaboration, innovative technologies, and a deeper understanding of transmission dynamics are crucial. Multisectoral coordination under the One Health framework, with long-term political commitment and national and international cooperation, is critical for effective control in endemic areas.

Enhancing the therapeutic potential of P29 protein-targeted monoclonal antibodies in the management of alveolar echinococcosis through CDC-mediated mechanisms

Alveolar echinococcosis (AE) is a highly lethal helminth infection. Current chemotherapeutic strategies for AE primarily involve the use of benzimidazoles (BZs) such as mebendazole (MDZ) and albendazole (ABZ), which exhibit limited efficacy. In a previous study, the vaccine of recombinant Echinococcus granulosus P29 (rEgP29) showed significant immunoprotection against E. granulosus in both mice and sheep. In the current study, we utilized hybridoma technology to generate five monoclonal antibodies (mAbs) against P29, among which 4G10F4 mAb exhibited the highest antigen-specific binding capacity. This mAb was selected for further investigation of anti-AE therapy, both in vivo and in vitro. In vitro, 4G10F4 inhibited a noteworthy inhibition of E. multilocularis protoscoleces and primary cells viability through complement-dependent cytotoxicity (CDC) mechanism. In vivo, two experiments were conducted. In the first experiment, mice were intraperitoneally injected with Em protoscoleces, and subsequently treated with 4G10F4 mAb (2.5/5/10 mg/kg) at 12 weeks postinfection once per week for 8 times via tail vein injection. Mice that were treated with 4G10F4 mAb only in dosage of 5mg/kg exhibited a significant lower mean parasite burden (0.89±0.97 g) compared to isotype mAb treated control mice (2.21±1.30 g). In the second experiment, mice were infected through hepatic portal vein and treated with 4G10F4 mAb (5mg/kg) at one week after surgery once per week for 8 times. The numbers of hepatic metacestode lesions of the 4G10F4 treatment group were significantly lower in comparison to the isotype control group. Pathological analysis revealed severe disruption of the inner structure of the metacestode in both experiments, particularly affecting the germinal and laminated layers, resulting in the transformation into infertile vesicles after treatment with 4G10F4. In addition, the safety of 4G10F4 for AE treatment was confirmed through assessment of mouse weight and evaluation of liver and kidney function. This study presents antigen-specific monoclonal antibody immunotherapy as a promising therapeutic approach against E. multilocularis induced AE.

Successful control of Echinococcosis in Argentina and Chile through a One Health approach, including vaccination of the sheep intermediate host

Cystic echinococcosis control in South American countries requires a comprehensive integrative ‘One Health’ approach. While insular nations have seen successful in their elimination programmes, South American countries face persistent challenges in hostile environments, with Echinococcus granulosus s.l., posing a significant public health concern. Vaccination of intermediate hosts has demonstrated the efficacy of the EG95 vaccine in reducing transmission rates. For example, since 2009, Rio Negro Province in Argentina has added, with marked success, the EG95 vaccine to the control programme, supplementing dog deworming. The Aysen Region of Chile has also reported encouraging preliminary results in reducing cyst prevalence in vaccinated sheep after 3 years of vaccination. The challenges in aligning control strategies with socio-cultural factors, especially in indigenous communities, underlines the need for context-specific strategies. The Rio Negro programme demonstrated commendable compliance, underlining the importance of community engagement in achieving lasting success. The most promising strategies for effective echinococcosis control involved dog deworming and the routine vaccination of sheep and/or goats, underscoring the importance of sustained implementation until all grazing animals have been replaced. For lasting success, these interventions need to be combined with a robust surveillance system.

Plasma Circulating Cell-Free DNA Facilitated the Detection of an Alveolar Echinococcosis Patient Initially Misdiagnosed as Cystic Echinococcosis: A Case Report

Echinococcosis, especially alveolar echinococcosis (AE), is becoming an emerging/re-emerging disease with a growing number of cases reported globally. The diagnosis of echinococcosis is based mainly on imaging, which may be challenging when the image presentation is atypical. We reported one patient with suspected cystic echinococcosis (CE) by imaging. The cell-free DNA (cfDNA) obtained from sequencing the patient's plasma before the operation showed that this patient probably had AE with 45 reads mapped to the Echinococcus multilocularis reference genome (Read-Pairs Per Million = 0.24). The patients underwent surgery, and the pathological result showed that the patient had AE. The conventional polymerase chain reaction (PCR) of her lesion sample extraction also indicated that the infection was caused by Echinococcus multilocularis. The follow-up ultrasound after three months indicated no recurrence. We demonstrated that the differentiation of CE and AE by imaging may not be that easy, with further elaboration on the differentiation between AE and CE in different aspects. We demonstrated that it is possible to use patients' plasma cfDNA mapped to Echinococcus references before the operation to obtain the objective clue of the lesion to facilitate diagnosis.

An innovative strategy for deworming dogs in Mediterranean areas highly endemic for cystic echinococcosis

BACKGROUND

Cystic echinococcosis (CE), caused by the larval stage of Echinococcus granulosus sensu lato, is a zoonotic parasitic disease of economic and public health importance worldwide, especially in the Mediterranean area. Canids are the main definitive hosts of the adult cestode contaminating the environment with parasite eggs released with feces. In rural and peri-urban areas, the risk of transmission to livestock as well as humans is high because of the free-roaming behavior of owned/not owned dogs. Collecting data on animal movements and behavior using GPS dataloggers could be a milestone to contain the spread of this parasitosis. Thus, this study aims to develop a comprehensive control strategy, focused on deworming a dog population in a pilot area of southern Italy (Campania region) highly endemic for CE.

METHODS

Accordingly, five sheep farms, tested to be positive for CE, were selected. In each sheep farm, all shepherd dogs present were treated every 2 months with praziquantel. Furthermore, 15 GPS dataloggers were applied to sheep and dogs, and their movements were tracked for 1 month; the distances that they traveled and their respective home ranges were determined using minimum convex polygon (MCP) analysis with a convex hull geometry as output.

RESULTS

The results showed that the mean daily walking distances traveled by sheep and dogs did not significantly differ. Over 90% of the point locations collected by GPS fell within 1500 mt of the farm, and the longest distances were traveled between 10:00 and 17:00. In all the sheep farms monitored, the area traversed by the animals during their daily activities showed an extension of < 250 hectares. Based on the home range of the animals, the area with the highest risk of access from canids (minimum safe convex polygon) was estimated around the centroid of each farm, and a potential scheme for the delivery of praziquantel-laced baits for the treatment of not owned dogs gravitating around the grazing area was designed.

CONCLUSIONS

This study documents the usefulness of geospatial technology in supporting parasite control strategies to reduce disease transmission.

Changes in intestinal flora of mice induced by rEg.P29 epitope peptide vaccines

OBJECTIVE

Cystic echinococcosis (CE), a zoonotic parasitic disease caused by Echinococcus granulosus, remains a public health and socioeconomic issue worldwide, making its prevention and treatment of vital importance. The aim of this study was to investigate changes in the intestinal microbiota of mice immunized with three peptide vaccines based on the recombinant antigen of E. granulosus, P29 (rEg.P29), with the hope of providing more valuable information for the development of vaccines against CE.

METHODS

Three peptide vaccines, rEg.P29T , rEg.P29B , and rEg.P29T + B , were prepared based on rEg.P29, and a subcutaneous immunization model was established. The intestinal floras of mice in the different immunization groups were analyzed by 16 S rRNA gene sequencing.

RESULTS

The intestinal microbiota analysis at both immunization time points revealed that Firmicutes, Bacteroidota, and Verrucomicrobiota were the predominant flora at the phylum level, while at the genus level, Akkermansia, unclassified_Muribaculaceae, Lachnospiraceae_NK4A136_group, and uncultured_rumen bacterium were the dominant genera. Some probiotics in the intestines of mice were significantly increased after immunization with the peptide vaccines, such as Lactobacillus_taiwanensis, Lactobacillus_reuteri, Lachnospiraceae_NK4A136_group, Bacteroides_acidifaciens, and so forth. Meanwhile, some harmful or conditionally pathogenic bacteria were decreased, such as Turicibacter sanguinis, Desulfovibrio_fairfieldensis, Clostridium_sp, and so forth, most of which are associated with inflammatory or infectious diseases. Kyoto Encyclopaedia of Genes and Genomes enrichment analysis revealed that the differential flora were enriched in multiple metabolic pathways, primarily biological systems, human diseases, metabolism, cellular processes, and environmental information processing.

CONCLUSION

In this study, we comprehensively analyzed and compared changes in the intestinal microbiota of mice immunized with three peptide vaccines as well as their related metabolic pathways, providing a theoretical background for the development of novel vaccines against E. granulosus.

IgG glycomic profiling identifies potential biomarkers for diagnosis of echinococcosis

Echinococcosis caused by larval stage of the genus Echinococcus, is a serious and potentially fatal parasitic zoonosis distributed globally. The two types of the disease in human are cystic echinococcosis (CE) and alveolar echinococcosis (AE). As the biological and encysting characteristics of the parasite, early diagnosis remains to address. In the present study, we demonstrate the value of Immunoglobulin G (IgG) glycome as a potential diagnostic biomarker for echinococcosis. Serum IgG glycome profiles were analyzed by ultra-performance liquid chromatography in a cohort comprised of 127 echinococcosis patients, of them 98 were diagnosed as CE and 29 as AE. IgG N-glycome analysis in pretreatment serum of echinococcosis patients presents 25 glycans and 64 derived traits. Compared with IgG glycans of healthy control group, neutral glycans, fucosylation and agalactosylated N-glycans increased while sialylation and galactosylation decreased in echinococcosis patients. Combined with a machine-learning-based approach, we built three biomarker combinations to distinguish CE, AE and healthy controls. Meanwhile, galactosylation, sialylation and A2BG2S1 in IgG glycan profiles were evidently associated with different types of CE (from CE1 to CE5). Our findings suggest that the alterations in IgG N-glycome may be of value in CE and AE diagnosis and follow-up CE disease progress. The role of IgG N-glycans as diagnostic biomarker remains to be verified in future study.

First isolation of Echinococcus granulosus sensu lato genotype 7 in the archipelago of Cape Verde

There are no scientific data available on the occurrence of the Echinococcus granulosus sensu lato (s.l.) cluster in definitive hosts (domestic dogs), intermediate hosts (domestic livestock) nor humans in Cape Verde. In this pilot study, environmental dog fecal samples (n = 369) were collected around food markets, official slaughterhouses, as well as home and small business slaughter spots in 8 of the 9 inhabited islands from the Cape Verde archipelago, between June 2021 and March 2022. Additionally, during the same period, 40 cysts and tissue lesions were opportunistically collected from 5 islands, from locally slaughtered cattle (n = 7), goats (n = 2), sheep (n = 1) and pigs (n = 26). Genetic characterization by a multiplex polymerase chain reaction assay targeting the 12S rRNA gene confirmed the presence of E. granulosus s.l. in fecal and tissue material. In total, 17 cyst samples from Santiago (n = 9), Sal (n = 7) and São Vicente (n = 1) and 8 G6/G7-positive dog fecal samples from Santiago (n = 4) and Sal (n = 4) were identified as E. granulosus s.l. G7 by sequence analysis (nad2, nad5 and nad1 genes). This study discloses the transmission of E. granulosus s.l. G7, in pig, cattle and dog in Cape Verde.

Environmental Influence on the Occurrence of Multi-Organ Cystic Echinococcosis Infection in a Patient from Sardinia, Italy

An uncommon clinical case of an adult woman who was referred to the hospital with severe symptoms attributable to cystic echinococcosis (CE) is described in this report. According to a questionnaire, the subject was exposed to a high risk of infection since she was employed on a farm about 20 years before diagnosis. She lived close to several animal species and handled vegetables in inadequate hygienic conditions. Medical and laboratory investigations confirmed the presence of massive echinococcal cystic lesions in each lung and in the liver. Given the peculiarity of the case, pharmacological and surgical treatments were the only conceivable option. The association of pharmacological treatment, surgery, and interventional radiology procedure represented a reliable and effective way to handle a complex case of human hydatidosis. A multi-disciplinary approach was mandatory, resulting in a clear and conclusive diagnosis of CE caused by the zoonotic parasite E. granulosus sensu stricto of the G1 genotype.

Identification of Omega-class glutathione transferases in helminths of the Taeniidae family

Glutathione transferase enzymes (GSTs) are believed to be a major detoxification system in helminth parasites and have been associated with immunomodulation of the host response. Echinococcus granulosus sensu lato (s.l.) is a cestode parasite known to express at least five different GSTs, but no Omega-class enzymes have been reported in this parasite or in any other cestode. Herein we report the identification of a new member of the GST superfamily in E. granulosus s.l., which is phylogenetically related to the Omega-class: EgrGSTO. Through mass spectrometry, we showed that the 237 amino acids protein EgrGSTO is expressed by the parasite. Moreover, we identified homologues of EgrGSTO in other eight members of the Taeniidae family, including E. canadensis, E. multilocularis, E. oligarthrus, Hydatigera taeniaeformis, Taenia asiatica, T. multiceps, T. saginata and T. solium. A manual sequence inspection and rational modification yielded eight Taeniidae's GSTO sequences, each one encoding for a 237 aa polypeptide showing 80.2% overall identity. To the best of our knowledge, this is the first description of genes encoding for Omega-class GSTs in worms belonging to the Taeniidae family -that at least in E. granulosus s.l. is expressed as a protein- suggesting the gene encodes for a functional protein.

Improvement of Antialveolar echinococcosis efficacy of novel Albendazole-Bile acids Derivatives with Enhanced Oral Bioavailability

Alveolar echinococcosis (AE) is a chronic and fatal infectious parasitic disease, which has not been well-researched. Current recommended therapies for AE by the World Health Organization include complete removal of the infected tissue followed by two years of albendazole (ABZ), administered orally, which is the only effective first-line anti-AE drug. Unfortunately, in most cases, complete resection of AE lesions is impossible, requiring ABZ administration for even longer periods. Only one-third of patients experienced complete remission or cure with such treatments, primarily due to ABZ's low solubility and low bioavailability. To improve ABZ bioavailability, albendazole bile acid derivative (ABZ-BA) has been designed and synthesized. Its structure was identified by mass spectrometry and nuclear magnetic resonance. Its physicochemical properties were evaluated by wide-angle X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and polarizing microscopy; it was compared with ABZ to assess its solubilization mechanism at the molecular level. To avoid the effects of bile acid on the efficacy of albendazole, the inhibitory effect of ABZ-BA on protoscolex (PSCs)s was observed in vitro. The inhibitory effect of ABZ-BA on PSCs was evaluated by survival rate, ultrastructural changes, and the expression of key cytokines during PSC apoptosis. The results showed that ABZ-BA with 4-amino-1-butanol as a linker was successfully prepared. Physicochemical characterization demonstrated that the molecular arrangement of ABZ-BA presents a short-range disordered amorphous state, which changes the drug morphology compared with crystalline ABZ. The equilibrium solubility of ABZ-BA was 4-fold higher than ABZ in vitro. ABZ-BA relative bioavailability (Frel) in Sprague-Dawley (SD) rats was 26-fold higher than ABZ in vivo. The inhibitory effect of ABZ-BA on PSCs was identical to that of ABZ, indicating that adding bile acid did not affect the efficacy of anti-echinococcosis. In the pharmacodynamics study, it was found that the ABZ-BA group had 2.7-fold greater than that of Albenda after 1 month of oral administration. The relative bioavailability of ABZ-BA is significantly better than ABZ due to the transformation of the physical state from a crystalline state to an amorphous state. Furthermore, sodium-dependent bile acid transporter (ASBT) expressed in the apical small intestine has a synergistic effect through the effective transport of bile acids. Therefore, we concluded that the NC formulation could potentially be developed to improve anti-AE drug therapy.

Food-borne zoonotic echinococcosis: A review with special focus on epidemiology

Echinococcosis is a neglected, WHO-listed cyclozoonotic parasitic disease that is caused by a number of species belonging to the genus Echinococcus. This disease is widespread across the globe, resulting in heavy economic losses for farmers and cystic disease in aberrant human hosts. This review paper briefly discussed taxonomy, a brief history, the magnitude of economic losses, host spectrum and life cycle, risk factors, and clinical manifestations. Furthermore, the copro- and sero-ELISA-based prevalence of echinococcosis on different continents was summarized. Finally, the authors analyzed the frequency and use of molecular epidemiology in the taxonomy of Echinococcus species based on molecular markers. This review will serve as a quick reference to Echinococcus.

Does the trained immune system play an important role in the extreme longevity that is seen in the Sardinian blue zone?

Villages in the island of Sardinia in the Mediterranean that display exceptional longevity are clustered within a defined mountainous region. Because of their unique location we hypothesize that these villages had a unique infectious disease exposure relevant to the observed successful longevity. These highland villages had a significant exposure to malaria in the first half of the 20th century after which malaria was eliminated due to vector control mechanisms. In addition, there is likely a high incidence of Helicobacter pylori infections among shepherds in Sardinia, the primary occupation of many living in the LBZ, as well as helminth infections among children. This suggests that individuals living in the LBZ had a unique infectious disease exposure. Specifically, we hypothesize that the continued high exposure of residents in the LBZ to these infectious agents prior to the 1950s lead to the generation of a uniquely trained (or imprinted) immune system. Once some of these diseases were eliminated in the latter half of the century, individuals within the LBZ were equipped with a trained immune system that was uniquely capable of not only responding effectively to common infections but also responding in a manner that maximized maintaining tissue health. In addition, there are lifestyle factors that also favor such a trained immune system. This hypothesis may help explain the slow progression of chronic immune mediated diseases as well as other chronic non-transmissible age-related diseases seen in the Sardinian LBZ and serve as a template for future studies that support or refute this hypothesis.

Societal drivers of human echinococcosis in China

BACKGROUND

Echinococcosis is a parasitic zoonotic disease that threatens human health and economic development. In China, 370 counties are endemic for echinococcosis. Qinghai-Tibet Plateau has the most patients and people at risk. Therefore, analyzing the societal factors related to susceptibility to the disease is critical for efficient prevention and control of echinococcosis.

METHODS

The demographic characteristics and lifestyle of echinococcosis cases were clustered using K-means cluster analysis to determine the main factors of risk of echinococcosis.

RESULTS

Middle-aged and young people as well as those with a low education level and herdsmen are at risk of contracting echinococcosis. Nomadism, domestic and feral dogs in the surrounding environment, and drinking heavily polluted natural surface water are the main behavioral risk factors. The cystic echinococcosis (CE) and alveolar echinococcosis (AE) cluster analysis focused on female, middle-aged, and young people, winter settlement and summer nomadism, and domestic and feral dogs in the surrounding environment. There were significant differences in lifestyle between Qinghai-Tibet Plateau cases and non-Qinghai-Tibet-Plateau cases.

CONCLUSION

According to the distribution of cases and CE and AE, this study identified the factors of risk of echinococcosis in the Qinghai-Tibet Plateau and non-Qinghai-Tibet Plateau. Adapted control techniques appropriate for the various epidemic areas should be established to serve as a reference for echinococcosis prevention.

The economic evaluation of Cystic echinococcosis control strategies focused on zoonotic hosts: A scoping review

BACKGROUND

Cystic echinococcosis (CE) is a zoonotic neglected tropical disease (zNTD) which imposes considerable financial burden to endemic countries. The 2021-2030 World Health Organization's roadmap on NTDs has proposed that intensified control be achieved in hyperendemic areas of 17 countries by 2030. Successful interventions for disease control, and the scale-up of programmes applying such interventions, rely on understanding the associated costs and relative return for investment. We conducted a scoping review of existing peer-reviewed literature on economic evaluations of CE control strategies focused on Echinococcus granulosus zoonotic hosts.

METHODOLOGY/PRINCIPAL FINDINGS

Database searches of Scopus, PubMed, Web of Science, CABI Direct and JSTOR were conducted and comprehensively reviewed in March 2022, using predefined search criteria with no date, field or language restrictions. A total of 100 papers were initially identified and assessed for eligibility against strict inclusion and exclusion criteria, following the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines. Bibliography review of included manuscripts was used to identify additional literature. Full review of the final manuscript selection (n = 9) was performed and cost data for control interventions were extracted.

CONCLUSIONS/SIGNIFICANCE

There are very little published data pertaining to the cost and cost effectiveness of CE control interventions targeting its zoonotic hosts. Data given for costs are often incomplete, thus we were unable to perform an economic analysis and cost effectiveness study, highlighting a pressing need for this information. There is much scope for future work in this area. More detailed information and disaggregated costings need to be collected and made available. This would increase the accuracy of any cost-effective analyses to be performed and allow for a greater understanding of the opportunity cost of healthcare decisions and resource allocation by stakeholders and policy makers for effective and cost-effective CE control.

Laparoscopic Treatment Strategies for Liver Echinococcosis

Liver echinococcosis is clinically mainly composed of hepatic cystic echinococcosis (CE) and hepatic alveolar echinococcosis (AE). At present, laparoscopy has been comprehensively applied in the treatment of two types of liver echinococcosis. For hepatic CE treatment, both laparoscopic total pericystectomy and laparoscopic hepatectomy can achieve radical results, but the former is considered the first choice owing to its being more minimally invasive; laparoscopic subtotal pericystectomy and laparoscopic partial pericystectomy can be accepted as complementary options, considering the presence of complicated cysts and the level of laparoscopic technique in remote hospitals; laparoscopic cystectomy is simple, but it is not currently recommended for treatment of hepatic CE owing to poor efficacy and high risk of postoperative complications. For hepatic AE treatment, laparoscopy not only achieves the same radical effect as open surgery in selected patients, but also is more minimally invasive, so it has a better prospect.

Assessment of echinococcosis control in Tibet Autonomous Region, China

BACKGROUND

In China the highest prevalence of echinococcosis is in Tibet Autonomous Region (TAR). The government has issued documents and implemented comprehensive prevention and control measures focusing on controlling the source of infection of echinococcosis. It was very important to understand the implementation and effect of infectious source control measures. The purpose of this study was to examine the implementation of measures to control infectious source (domestic and stray dogs) in TAR and to assess their effectiveness.

METHODS

We collected data on domestic dog registration and deworming and stray dog sheltering in 74 counties/districts in the TAR from 2017 to 2019. Fecal samples from domestic dogs were collected from randomly selected towns to determine Echinococcus infection in dogs using coproantigen ELISA. We analyzed the data to compare the canine rate of infection between 2016 and 2019. The data analysis was performed by SPSS statistical to compare dog infection rate in 2016 and 2019 by chi-square test, and ArcGIS was used for mapping.

RESULTS

From 2017 to 2019, 84 stray dog shelters were built in TAR, and accumulatively 446,660 stray or infected dogs were arrested, sheltered, or disposed of. The number of domestic dogs went downward, with an increased registration management rate of 78.4% (2017), 88.8% (2018), and 99.0% (2019). Dogs were dewormed 5 times in 2017, 12 times in 2018, and 12 times in 2019. The dog infection rate was 1.7% (252/14,584) in 2019, significantly lower than 7.3% (552/7564) from the survey of echinococcosis prevalence in Tibet in 2016 (P < 0.05).

CONCLUSION

Between 2017 and 2019, the number of stray dogs and infection rate of Echinococcus spp. in domestic dogs decreased significantly, indicating that dogs were effectively controlled as a source of infection in TAR and reflecting a significant decrease in the risk of echinococcosis transmission.

Assessment of the Vaccination Program against Cystic Echinococcosis in Sheep in the Pehuenche Community of Central Chile

Echinococcosis is a neglected zoonosis that uses dogs and sheep as its main hosts in Chile. The Eg95 vaccine against sheep infection has been included in some control programs. Here, we assess the efficacy of the vaccination program in the hyperendemic Alto Biobío commune after 3 years of execution. Fisher’s test and generalized linear models were used in the assessment. The program tried to offer a first dose at 2 months of age, a booster 1 month later, and yearly vaccination. Given logistic difficulties, important delays in vaccination occurred, and most animals did not receive the first booster. Dog deworming was not included in the program. Likely due to the aforementioned factors, the overall frequency of infection was not lower, but the proportion of large (>5 mm) cysts and fertile cysts was smaller after the program. The frequency of infection and/or the number of cysts were lower when the age at first dose was younger and the first booster was administered 1 month after the first dose. The results suggest that vaccination affects both cyst development after the larvae reach the target organs, as well as the development of the protoscolex once the cysts start developing.

Cystic Echinococcosis of Liver and Spleen Communicating to the Lung: A Rare Case

The annual cystic echinococcosis (CE) incidence in endemic countries is between 1 and 200 per 100,000 population. The clinical manifestations of CE are associated with damage or dysfunction of target organs and affect primarily the liver in around 70% of cases and lungs in around 20% of cases. The involvement of the spleen is rarely seen, representing 2 to 6% of all CE cases. We describe a 60-year-old female patient who presented with 15 days' history of intermittent fever and abdominal distension, having significant hepatosplenomegaly. CE was diagnosed involving the liver, spleen, and lungs and was confirmed radiologically and microbiologically. CE is caused by the larval or cystic stage of the zoonotic dog-tapeworm. Humans can be infected by ingestion of contaminated food or water. At present, there are nine species under the genus Echinococcus with E. granulosus sensu stricto having worldwide distribution, while the rest are focally distributed. CE involving multiple organs is rare. CE should be taken into consideration in patients with these symptoms in endemic areas.

In vivo and in vitro anti-hydatidosis effect of garlic: a systematic review

Background:

Hydatidosis is a parasitic disease caused by the larval stage of Echinococcus granulosus sensu lato. The aim of the current systematic review study was to clarify the effect of garlic on hydatid cyst in vivo and in vitro.

Method:

We performed our analyses up to Feb 20, 2021, in accordance with the PRISMA guideline. We systematically searched five English databases (Science Direct, PubMed, Scopus, Ovid and Cochrane) and four Persian databases (Scientific Information Database [SID], Iran Medex, Iran Doc, and Magiran) with appropriate syntax. The data was extracted from the relevant articles and analyzed.

Results:

From 160 studies obtained by initial search, nine studies were selected for further analysis. Among 6 in vitro study, 3 (50%) used methanolic extract, 2 (34%) hydroalcoholic and chloroformic extract, and 1 (16%) chloroformic extract. Two (67%) studies used BALB/c mice, and one study (33%) used Swiss albino mice. The method of treatment of mice in all studies was oral. The results showed that garlic has mild to potent effect on hydatidosis and this effect was more considerable in vitro than in vivo.

Conclusion:

Based on the results of various studies, it can be concluded that Allium sativum extract can be used as a suitable alternative to drugs such as Albendazole or can be used as complementary treatment to reduce the dose of the current drugs.

Status and prospect of novel treatment options toward alveolar and cystic echinococcosis

Cystic echinococcosis (CE) and alveolar echinococcosis (AE) are the two most important global parasitic infectious diseases caused by species of Echinococcus granulosus and E. multilocularis, respectively. Although numerous trials have been performed in search of novel therapeutic options to curb the neglected zoonosis, no other nonsurgical options are currently available to replace the licensed anti echinococcal drugs albendazole (ABZ) and mebendazole (MBZ). A safer and more effective treatment plan for echinococcosis is therefore urgently needed to compensate for this therapeutic shortfall. Here, we present a review of the literature for state-of-the-art valuable anti-parasitic compounds and novel strategies that have proved effective against CE and AE, which includes details about the pharmaceutical type, practical approach, experimental plan, model application and protoscolecidal effects in vivo and in vitro. The content includes the current application of traditional clinical chemicals, the preparation of new compounds with various drug loadings, repurposing findings, combined programs, the prospects for Chinese herbal medicines, non-drug administrations and the exploration of target inhibitors based on open-source information for parasitic genes. Next the conventional experimental projects and pharmacodynamic evaluation methods are systematically summarized and evaluated. The demands to optimize the construction of the echinococcosis model and improve the dynamic monitoring method in vivo are also discussed given the shortcomings of in vivo models and monitoring methods.

Genetic diversity and haplotypes of paediatric hydatid cyst isolates and first occurrence of E. canadensis (G6/G7) in paediatric cases in Turkey

Cystic echinococcosis (CE) is a neglected zoonotic tropical disease caused by Echinococcus granulosus sensu lato. The aim of this study was to investigate the genetic variation of hydatid cyst isolates obtained from surgically confirmed paediatric cases originating from two different regions in eastern Turkey. Seventeen paediatric cases aged between 6 and 16 were operated by open surgery, and the germinal layers of their cysts were obtained for further molecular analyses. After genomic DNA isolation, 875 bp mt-CO1 gene fragments were amplified in all samples by PCR. Then, the unidirectional sequence analyses of the PCR products were carried out. According to the BLAST analyses of 17 sequences, 16 of these sequences were matched with E. granulosus sensu stricto, while one sequence was identified as E. canadensis (G6/G7) for the first time in paediatric cases in Turkey. High haplotype diversity and low nucleotide diversity were observed in the E. granulosus s.s. sequences.

Expression and distribution of glutathione transferases in protoscoleces of Echinococcus granulosus sensu lato

Glutathione transferases (GSTs) belong to a diverse superfamily of multifunctional proteins involved in metabolic detoxification. In helminth parasite, GSTs are particularly relevant since they are also involved in host immunomodulation. Echinococcus granulosus sensu lato (s.l.) is a cestode parasite known to express at least three phylogenetically distant cytosolic GSTs: EgGST1 and EgGST2 previously grouped within Mu and Sigma classes, respectively; and EgGST3 related to both Omega and Sigma classes. To better characterize E. granulosus s.l. GSTs, herein their expression and distribution were assessed in the pre-adult protoscolex (PSC) parasite stage. Potential transcriptional regulatory mechanisms of the corresponding EgGST genes were also explored. Firstly, the transcription of the three EgGSTs was significantly induced during the early stages of the murine model of infection, suggesting a potential role during parasite establishment. EgGST1 was detected in the parenchyma of PSCs and its expression increased after H₂O₂ exposure, supporting its role in detoxification. EgGST2 was mainly detected on the PSCs tegument, strategically localized for potential immunoregulation functions due to its Sigma-class characteristics. In addition, its expression increased after anthelmintic treatment, suggesting a role in chemotherapy resistance. Finally, the Omega-related EgGST3 was localized throughout the entire PSC body, including suckers and tegument, and since its expression also increased after H₂O₂ treatment, a potential role in oxidative stress response could also be ascribed. On the other hand, known cis-acting regulatory motifs were detected in EgGST genes, suggesting similar transcription processes to other eukaryotes. The results herein reported provide additional data regarding the roles of EgGSTs in E. granulosus s.l. biology, contributing to a better understanding of its host-parasite interaction.

Spread of anthelmintic resistance in intestinal helminths of dogs and cats is currently less pronounced than in ruminants and horses - Yet it is of major concern

Anthelmintic resistance (AR) has thus far only rarely been reported for intestinal helminths of dogs and cats, in contrast to parasites of livestock and horses. We highlight possible reasons for this striking and important discrepancy, including ecological, biological and genetic factors and/or intervention regimens of key intestinal helminths concerning both host groups. In view of the current knowledge related to the genetics, mechanisms and principles of AR development, we point at issues which in our view contribute to a comparatively lower risk of AR development in intestinal helminths of dogs and cats. Finally, we specify research needs and provide recommendations by which, based on the available information about AR in ruminant and equine helminths, the development of AR in dog and cat helminths may best be documented, prevented or at least postponed.

Smart deworming collar: A novel tool for reducing Echinococcus infection in dogs

Echinococcosis is a serious zoonotic parasitic disease transmitted from canines to humans and livestock. Periodic deworming is recommended by the WHO/OIE as a highly effective measure against echinococcosis. However, manual deworming involves significant challenges, particularly in remote areas with scarce resources. The insufficient awareness delivering praziquantel (PZQ) baits for dogs leads to low compliance rate. The aim of this study was therefore to develop a novel smart collar for dogs to address these challenges. We developed a smart Internet of Things (IoT)-based deworming collar which can deliver PZQ baits for dogs automatically, regularly, quantitatively with predominant characteristics of being waterproof, anti-collision, cold-proof and long life battery. Its performance was tested in two remote locations on the Tibetan Plateau. A cross-sectional survey was conducted to evaluate the compliance of the dog owners. Further, a randomized controlled study was performed to evaluate the difference between smart-collar deworming and manual deworming. The collar's effectiveness was further assessed on the basis of Generalized Estimation Equations (GEE). The testing and evaluation was done for 10 smart deworming collars in factory laboratory, 18 collars attached for 18 dogs in Seni district, Tibet Autonomous Region, China, and 523 collars attached for 523 dogs in Hezuo city, Gansu province, China. The anti-collision, waterproof, and coldproof proportion of the smart collars were 100.0%, 99.5%, and 100.0%, respectively. When compared to manual deworming, the dogs' risk of infection with Echinococcus on smart-collar deworming is down to 0.182 times (95% CI: 0.049, 0.684) in Seni district and 0.355 (95%CI: 0.178, 0.706) in Hezuo city, the smart collar has a significant protective effect. The owners' overall compliance rate to attach the smart collars for their dogs was 89%. The smart deworming collar could effectively reduce the dogs' risk of infection with Echinococcus in dogs, significantly increase the deworming frequency and coverage and rapidly remove worm biomass in dogs. Thus, it may be a promising alternative to manual deworming, particularly in remote areas on the Tibetan Plateau.

Educational Intervention for the Awareness Improvement and Control Programme Design on Echinococcosis in Izmir, Turkey

In Turkey, cyst hydatid disease (CHD) or cystic echinococcosis (CE) is publicly known as “dog cyst”, a fatal and serious disease not only affects livestock husbandry and human health but also brings about economic loss to our country. According to the data of the Ministry of Health; number of annual cases was 408 in 2008, and this number reached 1,867 by the end of 2019. Cystic echinococcosis is especially taken up during childhood and emerged at an older age. They become exposed to the eggs of the tapeworm after close contact with an infected dog or its contaminated environment. The infected dogs also pass in their feces E. granulosus eggs that adhere to the dogs’ hairs, and pass on to the children who are in the course of playful and intimate contact with the infected dogs. This study was to create the awareness of risk factors of CE among 10 different districts of Izmir province. Awareness raising seminars are essential component of this study because local people living in CE endemic areas, are crucial to continue and sustain the long-time effort that is needed to tackle this disease. In each district, 3 awareness raising seminars were held to the target groups: (a) in schools for students, teachers, administrators, (b) for general public, (c) for healthcare professionals. 4090 students attended to the trainings, 242 administrators and teachers who attended to the presentations together with the students, 524 people were attended to the trainings and 327 health workers attended to the trainings from different institutions. This study helped improving this situation by organising educational events for the rural populations for preventing transmission of the disease. This is the first educational intervention study regarding creating awareness on CE in Izmir Province which includes 10 districts between January 2019 to January 2020.

Prevalence and spatial distribution patterns of human echinococcosis at the township level in Sichuan Province, China

Background

Echinococcosis is a global zoonotic parasitic disease caused by Echinococcus larvae. This disease is highly endemic in Sichuan Province, China. This study investigates the prevalence and spatial distribution characteristics of human echinococcosis at the township level in Sichuan Province, geared towards providing a future reference for the development of precise prevention and control strategies.

Methods

Human prevalence of echinococcosis was evaluated using the B-ultrasonography diagnostic method in Sichuan Province between 2016 and 2019. All data were collected, collated, and analyzed. A spatial distribution map was drawn to intuitively analyze the spatial distribution features. Eventually, the spatial autocorrelation was specified and local indicators of spatial association (LISA) clustering map was drawn to investigate the spatial aggregation of echinococcosis at the township level in Sichuan Province.

Results

The prevalence of echinococcosis in humans of Sichuan Province was 0.462%, among which the occurrence of cystic echinococcosis (CE) was 0.221%, while that of alveolar echinococcosis (AE) was 0.244%. Based on the results of the spatial distribution map, a predominance of echinococcosis in humans decreased gradually from west to east and from north to south. The Global Moran’s I index was 0.77 (Z = 32.07, P < 0.05), indicating that the prevalence of echinococcosis in humans was spatially clustered, exhibiting a significant spatial positive correlation. Further, the findings of local spatial autocorrelation analysis revealed that the “high–high” concentration areas were primarily located in some townships in the northwest of Sichuan Province. However, the “low–low” concentration areas were predominantly located in some townships in the southeast of Sichuan Province.

Conclusions

Our findings demonstrated that the prevalence of echinococcosis in humans of Sichuan Province follows a downward trend, suggesting that the current prevention and control work has achieved substantial outcomes. Nevertheless, the prevalence in humans at the township level is widely distributed and differs significantly, with a clear clustering in space. Therefore, precise prevention and control strategies should be formulated for clusters, specifically strengthening the “high–high” clusters at the township level.

Graphic Abstract

Community Based Assessment of Behavior and Awareness of Risk Factors of Cystic Echinococcosis in Major Cities of Pakistan: A One Health Perspective

Background: The parasitic disease, cystic echinococcosis (CE), is a serious health problem in Pakistan. Risk of disease transmission is increased by economic and political instability, poor living conditions, and limited awareness of hygienic practices. The current study aimed to investigate the community perception and awareness regarding the risk factors of CE in Pakistan, from a One Health perspective. Methods: We conducted a community-based survey involving 454 participants in the major cities of Pakistan. Quantitative data based on knowledge, attitude, and practices (KAP), the One Health concept, risk factors, and community perception of CE among the general population of the major cities of Pakistan were collected. The questions included those related to knowledge, attitude, practices, One Health concept, risk factors, and community perception. The Chi-squared test was applied to determine the associations regarding KAPs across socio-demographic parameters. Results: KAPs had no significant associations with sociodemographic aspects such as age, sex, religion, ethnicity, education, marital status, occupation, or financial status of the participants. The findings indicated a lack of awareness about CE among the participants. Respondents were unaware of the risk factors and the One Health concept of CE. However, the community attitude and perception were positive toward the control of CE. Conclusion: Illiteracy, deficient sanitation systems and lack of awareness are the contributing factors to CE in Pakistan. It is necessary to make the community aware regarding CE and its importance. Increasing this awareness represents an important step toward the eradication and control of CE.

Vaccination with rEGVac elicits immunoprotection against different stages of Echinococcus granulosus life cycle: A pilot study

Vaccination against dog-sheep transmission cycle is necessary to control cystic echinococcosis (CE) infection. A multi-epitope multi-antigenic recombinant vaccine was developed-comprising the three putative vaccine antigens EG95, Eg14-3-3 and EgEnolase-was cloned and expressed. In a pilot experiment, the multi-antigen vaccine was assessed in 15 dogs and 15 sheep (five experimental groups and three animals in each group) by two subcutaneous doses 28 days apart. To evaluate the efficacy of the vaccine candidate first immunological analysis were done comprising IgG and IgE antibodies and the cytokine IL-4 in sera of the immunized dogs and sheep. Serum IgG, IgE, and IL-4, in particular in the dogs, were increased after the two rounds of vaccine candidate injection, while the total number of hydatid cysts was reduced (~85.43%). This pilot trial indicated significant immune protection efficacy against E. granulosus especially in dogs, while its efficacy in sheep was not as high as dogs. The multi-antigenic candidate vaccine is proposed as a protective vaccine modality in both dogs and sheep.

Feasibility and acceptability of a new integrated approach to control cystic echinococcosis in Morocco: Vaccination of sheep and anthelmintic treatment of dogs

Cystic echinococcosis (CE) or hydatidosis is a common parasitic disease worldwide, especially in poor and developing countries. In Morocco, CE is a major zoonosis, despite the implementation of a national control program since 2007. Therefore, in 2016, a field trial that associates the EG95 vaccine (lambs) and anthelmintic treatment (dogs) was started in the Mid Atlas, the most endemic region in Morocco, with preliminary positive results. Here, a qualitative approach was used to analyze the feasibility and social acceptability of this strategy. Fifteen focus group discussions were separately conducted with breeders and with their wives, and forty-two individual interviews were performed with private-sector veterinarians and officers from structures responsible for the CE control program. Recordings were transcribed and analyzed with the R software, using the RQDA package. This qualitative research was validated using the credibility, transferability, dependability and confirmability criteria. This study showed that the professionals' views on sheep vaccination and anthelmintic treatment were divided between acceptability and concerns. Conversely, breeders and their wives highlighted the issue of the costs of procedures the utility of which was not immediately clear to them. All participants proposed solutions to improve this strategy, and also stressed the lack of education on CE. By bringing together the views of the communities and the professionals, this study traced the main lines (targeting the different aspects of CE and taking into account the local socio-cultural beliefs) that must be taken into account to ensure the short- and long-term CE control in Morocco.

Endocystectomy as a conservative surgical treatment for hepatic cystic echinococcosis: A systematic review with single-arm meta-analysis

BACKGROUND

In patients with hepatic cystic echinococcosis (CE), treatment effectiveness, outcomes, complications, and recurrence rate are controversial. Endocystectomy is a conservative surgical approach that adequately removes cyst contents without loss of parenchyma. This conservative procedure has been modified in several ways to prevent complications and to improve surgical outcomes. This systematic review aimed to evaluate the intraoperative and postoperative complications of endocysectomy for hepatic CE as well as the hepatic CE recurrence rate following endocystectomy.

METHODS

A systematic search was made for all studies reporting endocystectomy to manage hepatic CE in PubMed, Web of Science, and Cochrane CENTRAL databases. Study quality was assessed using the methodological index for non-randomized studies (MINORS) criteria and the Cochrane revised tool to assess risk of bias in randomized trials (RoB2). The random-effects model was used for meta-analysis and the arscine-transformed proportions were used to determine complication-, mortality-, and recurrence rates. This study is registered with PROSPERO (number CRD42020181732).

RESULTS

Of 3,930 retrieved articles, 54 studies reporting on 4,058 patients were included. Among studies reporting preoperative anthelmintic treatment (31 studies), albendazole was administered in all of them. Complications were reported in 19.4% (95% CI: 15.9-23.2; I2 = 84%; p-value <0.001) of the patients; biliary leakage (10.1%; 95% CI: 7.5-13.1; I2 = 81%; p-value <0.001) and wound infection (6.6%; 95% CI: 4.6-9; I2 = 27%; p-value = 0.17) were the most common complications. The post-endocystectomy mortality rate was 1.2% (95% CI: 0.8-1.8; I2 = 21%; p-value = 0.15) and the recurrence rate was 4.8% (95% CI: 3.1-6.8; I2 = 87%; p-value <0.001). Thirty-nine studies (88.7%) had a mean follow-up of more than one year after endocystectomy, and only 14 studies (31.8%) had a follow-up of more than five years.

CONCLUSION

Endocystectomy is a conservative and feasible surgical approach. Despite previous disencouraging experiences, our results suggest that endocystectomy is associated with low mortality and recurrence.

Cystic echinococcosis: an emerging zoonosis in southern regions of Khyber Pakhtunkhwa, Pakistan

Background

Cystic echinococcosis (CE) is one of the principal causes of economic loss to the livestock industry because of its morbidity and mortality of food-producing animals and condemnation of important visceral organs. Pakistan being an agricultural country having an extensive livestock sector, is mostly practiced by poor people, which has a fundamental role in the economy. The present study was aimed to conduct a cross-sectional survey and PCR based confirmation of Echinococcus granulosus in sheep, goats, cows, and buffaloes from southern regions (three districts: Lakki Marwat, Bannu, and Karak) of Khyber Pakhtunkhwa, Pakistan. During the study, a total of 2833 animals were examined randomly including; sheep (n = 529), goats (n = 428), cows (n = 1693), and buffaloes (n = 183). Hydatid cysts were collected and examined for the presence of protoscoleces using microscopy. Detection of DNA was performed by using PCR and two mitochondrial genetic markers namely; NAD-1 and COX-1 were amplified.

Results

The overall prevalence of CE was found to be (9%) among the examined animals. The hydatid cyst infection was highly prevalent in buffaloes (12%), followed by sheep (10%), cows (9%), and goats (5.1%). Cystic echinococcosis was more prevalent (10%; 96/992) in district Lakki Marwat followed by district Bannu (9%; 112/1246) and Karak (7%; 39/595). Female animals were more likely to be infected with CE (11.6%) than male animals (5.3%) (p = 0.001). Similarly, the infection was higher in the older group of animals as compared to younger (p = 0.001). Mostly (52.2%; n = 129) of hydatid cysts were found in the liver, while (64.4%; n = 159) cysts of the infected animals were infertile. PCR based identification confirmed the presence of E. granulosus sensu stricto (s.s) in the study area.

Conclusion

Cystic echinococcosis was found to be highly prevalent in southern regions of Khyber Pakhtunkhwa and could be a potential threat to human health. Moreover, molecular sequencing and phylogenetic analyses should be carried out in future to identify the prevailing genotype (s) of E. granulosus s.s.

Dynamic modeling and optimal control of cystic echinococcosis

BACKGROUND

Cystic echinococcosis is one of the most severe helminth zoonosis with a drastic impact on human health and livestock industry. Investigating optimal control strategy and assessing the crucial factors are essential for developing countermeasures to mitigate this disease.

METHODS

Two compartment models were formulated to study the dynamics of cystic echinococcosis transmission, to evaluate the effectiveness of various control measures, and to find the optimal control strategy. Sensitive analyses were conducted by obtaining PRCCs and contour plot was used to evaluate the effect of key parameters on the basic reproduction number. Based on forward-backward sweep method, numerical simulations were employed to investigate effects of key factors on the transmission of cystic echinococcosis and to obtain the optimal control strategy.

RESULTS

The food resources of stray dog and invalid sheep vaccination rate, which are always neglected, were significant to the transmission and control of cystic echinococcosis. Numerical simulations suggest that, the implementation of optimal control strategy can significantly reduce the infections. Improving the cost of health education and domestic dog deworming could not decrease human infections.

CONCLUSIONS

Our study showed that only a long-term use of the optimal control measures can eliminate the disease. Meanwhile, during the intervention, sheep vaccination and stray dogs disposing should be emphasized ahead of domestic dogs deworming to minimize the control cost. Simultaneously reducing other wild intermediate hosts and strengthening the sheep vaccination as well as disposing the stray dogs would be most effective.

Control of cystic echinococcosis in the Middle Atlas, Morocco: Field evaluation of the EG95 vaccine in sheep and cesticide treatment in dogs

BACKGROUND

Cystic echinococcosis (CE) is an important cause of human morbidity and mortality worldwide, particularly in Morocco and other North African countries.

METHODOLOGY/PRINCIPAL FINDINGS

We investigated the potential of three strategies to reduce Echinococcus granulosus transmission: (1) 4-monthly treatment of dogs with praziquantel, (2) vaccination of sheep with the EG95 vaccine and (3) a combination of both measures. These measures were implemented during four consecutive years in different areas of the Middle Atlas Mountains in Morocco. The outcome of the interventions was assessed through hydatid cyst (viable and non-viable) counts in liver and lungs using necropsy or in vivo ultrasound examination of the liver. A total of 402 lambs were recruited for annual vaccination with the EG95 anti-E. granulosus vaccine and 395 similar lambs were selected as non-vaccinated controls. At approximately four years of age the relative risk (estimated as odds ratio) for vaccinated sheep to have viable hydatid cysts compared with non-vaccinated controls was 3% (9.37% of the vaccinated sheep were found infected while 72.82% of the controls were infected; p = 0.002). The number of viable cysts in vaccinated animals was reduced by approximately 97% (mean counts were 0.28 and 9.18 respectively; p<0.001). An average of 595 owned dogs received 4-monthly treatment during the 44 months trial, corresponding to 91% of the owned dog population. Approximately, 5% of them were examined for E. granulosus adult worms by arecoline purge or eggs in feces (confirmed by PCR). The proportion of infected dogs significantly decreased after treatment (12% versus 35%; p<0.001). Post-treatment incidence of re-infestation corresponded to a monthly risk of 4% (95% CI: 3-6%). Treatment of owned dogs on a 4-monthly basis did not reduce the level of transmission of E. granulosus to sheep, nor did it enhance the level of control generated by vaccination of sheep with EG95, possibly because of unowned dogs and wild canids were not treated.

CONCLUSIONS/SIGNIFICANCE

These data suggest that vaccination of sheep with EG95 has the potential to reduce the level of CE in Morocco and in other parts of the world with similar transmission dynamics. Under the epidemiological circumstances existing in the trial area, 4-monthly treatment of owned dogs with praziquantel was insufficient to have a major impact of E. granulosus transmission to sheep.

Soluble programmed death-1 (sPD-1) as predictor of early surgical outcomes of paediatric cystic echinococcosis

AIMS

Following treatment, cystic echinococcosis (CE) exhibits a relatively high relapse rate. Here, we evaluated the value of soluble programmed death-1 (sPD-1), sPD-1 ligand (sPD-L1) and anti-recP29 antibody concentrations, as predictors of early surgical treatment outcomes in young CE-affected patients.

METHODS AND RESULTS

This prospective study included 59 Tunisian children (177 plasmas), where CE was surgically treated and monitored for 3 post-operative years. Based on CE post-surgical development, patients were clustered into a 'No relapsed' CE (NRCE; n = 39) and a 'Relapsed' CE (RCE; n = 20) group. Plasma levels of sPD-1, sPD-L1 and anti-recP29 IgG were measured using ELISA. In the NRCE group, sPD-1, sPD-L1 and anti-recP29 IgG concentrations were significantly lower at D365 than at D30. By contrast, in the RCE group, no significant difference was observed between D0, D30 and D365. When considering individual variations, the probability to be 'relapse-free' was 67% and 73% when anti-recP29 IgG and sPD-L1 level, respectively, decreased between D30 and D365. The probability to be 'relapse-free' was 86% when the sPD-1 level decreased between D30 and D365 (P = .003; chi-square test).

CONCLUSION

sPD-1 may be a useful biomaker for the early evaluation of surgical procedure efficacy in paediatric CE cases.

Echinococcus granulosus sensu lato and Echinococcus multilocularis: A review

Echinococcus spp. have a global distribution and are found on every continent except Antarctica. Infections with these parasites are considered extremely serious, contributing to significant morbidity and mortality in addition to substantial economic losses to the livestock industry. Echinococcus granulosus sensu lato (s.l.) and Echinococcus multilocularis, causing cystic echinococcosis (CE) and alveolar echinococcosis (AE) respectively, are the two main species of interest from a human and veterinary perspective. This review collates the current state-of-the-art understanding of these two parasites within four key areas of relevance to human and veterinary professionals: transmission and epidemiology, clinical signs and pathogenesis, diagnosis, and treatment and prevention. This review should serve as a broad introduction to the most important Echinococcus spp. The reader is advised to seek out specific literature on individual diseases and their causative parasites for a deeper understanding.

Spatial epidemiology of cystic echinococcosis in livestock from a hyper-endemic region in southern Chile

Cystic echinococcosis (CE) is a parasitic zoonosis, caused by the larval stage of Echinococcus granulosus. This disease has a worldwide distribution and is considered an important zoonosis in Chile, especially in regions where raising livestock dominates. We aimed to describe the spatial distribution and risk factors for CE in cattle and sheep slaughtered in the Aysén Region, Chile between 2015 and 2016, to inform disease control in this hyper-endemic region. Clustering and hotspot analyses of CE at the farm-level were performed (Moran's global index, local indicator of spatial autocorrelation (LISA), and the scan statistic Poisson model), and we used spatial interpolation to display areas with a higher risk of CE. Mixed effects logistic regression models were fit to assess the association between municipality of origin and age of animals and CE detected at slaughter, with the farm of origin included as a random effect. Overall, data from 1532 cattle farms (1078 geocoded) and 30,805 cattle were analyzed, with a 64 % and 39 % CE prevalence at the farm and animal-level, respectively. For sheep farms, data from 381 (296 geocoded) farms and 58,223 sheep were analyzed, with a 71 % and 18 % CE prevalence at the farm and animal-level, respectively. Globally, the CE prevalence in both cattle and sheep farms was not clustered. However, we found 14 cattle and 23 sheep farms with high prevalence that were locally clustered. We also detected 6 and 11 clusters in cattle and sheep farms, respectively. Risk of reported CE varied according to municipalities of origin, and the age of animals. This study confirms that the Aysén region is a hyper-endemic region for CE. It demonstrates the usefulness of the traceability of animals slaughtered for understanding the epidemiology of CE. The results suggest that in this hyper-endemic region in which there are limited financial resources available, that intervention activities - at the beginning of a control program - should be focused on farms with high prevalence and identified disease clusters.

The effects of dog management on Echinococcus spp. prevalence in villages on the eastern Tibetan Plateau, China

BACKGROUND

The pastoral area of the eastern Tibetan Plateau is highly endemic for human echinococcosis. Domestic dogs are the main definitive host for the transmission of both Echinococcus granulosus (sensu lato) and E. multilocularis to humans. To control the infection risks, a national-level canine echinococcosis prevention and control programme has been implemented since 2015 in Shiqu County, Ganze Tibetan Autonomous Prefecture, Sichuan, China. The objective of this study was to evaluate its effect on Echinococcus spp. prevalence in dogs.

METHODS

We surveyed 69 households with 84 owned dogs, for dog fecal samples and dog keeping information in the villages of Rizha and Eduoma. A total of 105 dog fecal samples (75 from owned dogs and 30 unknown dog fecal samples) were collected between 2015-2017 to determine Echinococcus spp. prevalence using copro-PCR. Eight variables based on household surveys were included into a logistic regression model for significant risk factors to canine echinococcosis prevalence in dogs.

RESULTS

Between 2015-2017, the overall Echinococcus spp. copro-DNA prevalence decreased significantly in dogs from 51.2% (2015) to 20.0% (2017) in Rizha, and insignificantly from 11.5% (2016) to 4.3% (2017) in Eduoma. Echinococcus multilocularis was the most prevalent species continually copro-DNA detected during the entire study period, while E. granulosus was rare and not detected in 2017. Echinococcus shiquicus copro-DNA prevalence (a probable non-zoonotic wildlife species) was as high in dogs as that of E. multilocularis, although only detected in 2015 in Rizha. Unleashed dog feces were mainly collected in Rizha in 2015. Although 93.2% of owned dogs were leashed, and the monthly praziquantel dosing rate reached 97%, E. multilocularis infection could still be detected in 11.1% of owned dogs in 2017. Monthly deworming, leashing dogs 24 h per day, and the avoidance of dogs feeding on livestock viscera were significant measures to prevent canine echinococcosis infection in owned dogs.

CONCLUSIONS

Carrying out a canine echinococcosis prevention and control programme can significantly decrease Echinococcus spp. prevalence. The potential contact between leashed dogs and wild small mammals is still a risk for re-infection of owned dogs with E. multilocularis. This study shows that the long-term application of regular dog treatment with praziquantel in the vast and remote echinococcosis endemic areas of the eastern Tibetan Plateau can reduce transmission in dogs but remains a challenging intervention.

Identification of potential 'hot spots' of cystic echinococcosis transmission in the province of Río Negro, Argentina

Cystic echinococcosis (CE) is a parasitic zoonosis caused by Echinococcus granulosus. The control program of CE of Rio Negro province, Argentina, involves annual surveillance using ultrasound (US) screening in school children, and five-year cross-sectional surveys to detect livestock farms with parasitized dogs by coproELISA with confirmation tests (Western Blot or PCR). Control program is based on deworming of dogs with praziquantel and the aim is to identify areas at risk of Cystic echinococcosis transmission to humans, using all available data sources. The information was spatially distributed in 13 program areas and, at a smaller geographical scale, in 80 Primary Health Care Centers. CoproELISA surveys involved three randomized sampling periods (2003-05, 2009-10, 2017-18), with 1790 canine fecal samples. The US surveys were conducted in 2003-08, 2009-16 and 2017-18 in 34,515 children. Heat maps were created at the smallest geographic scale with QGIS 3.4.6. For the consecutive sampling periods, prevalence of positive canine fecal samples from livestock farms were 14.7, 12.1 and 7.8%, respectively, and children prevalence was 0.4, 0.2 and 0.1%, respectively. The study has been developed on a scale according to which the temporal-spatial distribution of CE allows to adjust control strategies in those areas of potential transmission of the zoonosis to humans.

Reinventing the Wheel of Echinococcus granulosus sensu lato Transmission to Humans

Control of cystic echinococcosis (CE) relies on interrupting Echinococcus granulosus sensu lato transmission through interventions in dogs and livestock. However, primary prevention measures aimed at avoiding ingestion of Echinococcus eggs may help reduce the burden of human CE. CE is generally considered, to variable extents, to be foodborne, but there is little evidence on the actual contamination of matrices and sociocultural factors involved in parasite transmission. An overall appraisal of published literature suggests that environmental contamination, possibly through hand-to-mouth transmission, may be of primary importance. While in most endemic areas sufficient epidemiological information is available to start CE control programs, identifying the main sources of infection to humans would allow optimization of site-specific interventions while avoiding irrelevant health education messages.

Toxocara: Protecting pets and improving the lives of people

Toxocara sp. are zoonotic parasitic roundworms that cause infection and morbidity in both developed and developing countries. In humans, infection is thought to be most common in children, particularly those living in poverty, and usually results from consumption of soil contaminated with parasite eggs deposited by dog or cat faeces. Infection in humans results in different clinical manifestations, some more overt like visceral or ocular larva migrans and others more cryptic like neurocognitive delay. Despite its pervasiveness, toxocariasis has become a neglected infection. We review the dynamics of the human-animal interface in the context of this parasite, discuss the challenges in controlling transmission to humans, and cite key areas of research that could enable improved interventions. With political will and proper resource allocation, we propose that effective interventions are possible in the near term.

Control of cystic echinococcosis: Background and prospects

Cystic echinococcosis (CE), caused by Echinococcus granulosus, is a chronic and debilitating zoonotic larval cestode infection in humans, which is principally transmitted between dogs and domestic livestock, particularly sheep. Human CE occurs in almost all pastoral communities and rangeland areas of the underdeveloped and developed world. Control programmes against CE have been implemented in several endemic countries to reduce or eliminate the disease. New Zealand and Tasmania are examples of some of the first programmes to be undertaken (in insular territories) and which were very successful in the elimination of CE. The advent and proven effectiveness of praziquantel, plus the experience of insular models, produced high expectations for rapid advances in a second generation of control programmes undertaken in continental areas (Argentina, Uruguay and Chile). Nevertheless, only moderate gains in CE control have been made and the impact on prevalence among humans has been slight. A major impediment to the adoption of procedures that were successful in New Zealand and Tasmania has been the requirement to administer praziquantel to dogs in rural areas eight times per year over numerous years. In addition, there have been clear technological improvements made in the diagnosis of canine echinococcosis for surveillance, the genetic characterization of parasite strains and in vaccination against CE infection in livestock. In order to establish new paradigms and appropriate combinations of control strategies, we have carried out a review and discussion of the available control tools and control models. Control strategies must be suitable and sustainable to benefit the Echinococcosis-endemic areas primarily, which at the same time are the poorest regions of the world.

The pattern of cystic echinococcosis in children in an endemic area in Morocco

Cystic echinococcosis is a parasitic infection of major public health concern. The infection is generally acquired during childhood and the disease incubation period can last many years. The occurrence and characteristics of the disease in children were not well studied. The present study aimed to explore the pattern and features of cystic echinococcosis in children in rural and urban environments in Morocco. A total of 338 children diagnosed and treated for cystic echinococcosis were investigated. The trend of the infection, risk and exposure factors and the distribution of the anatomic locations of cysts were studied. A non-uniform decrease in proportions of infected children was found. Children from rural environs had significantly higher infection rates than children from urban environs (p < 0.001). Males were significantly more infected than females. Children aged 7-11 years were the most affected. For cysts locations, single organ involvement was found in 94.4% of the children versus 5.6% with multi-organ localization. Despite control program, active transmission of echinococcosis still occurred in children and remains a major public health problem. The infection in younger population may have some features that need to be considered in the prevention and control programs in endemic areas.

Echinococcosis: Advances in the 21st Century

Echinococcosis is a zoonosis caused by cestodes of the genus Echinococcus (family Taeniidae). This serious and near-cosmopolitan disease continues to be a significant public health issue, with western China being the area of highest endemicity for both the cystic (CE) and alveolar (AE) forms of echinococcosis. Considerable advances have been made in the 21st century on the genetics, genomics, and molecular epidemiology of the causative parasites, on diagnostic tools, and on treatment techniques and control strategies, including the development and deployment of vaccines. In terms of surgery, new procedures have superseded traditional techniques, and total cystectomy in CE, ex vivo resection with autotransplantation in AE, and percutaneous and perendoscopic procedures in both diseases have improved treatment efficacy and the quality of life of patients. In this review, we summarize recent progress on the biology, epidemiology, diagnosis, management, control, and prevention of CE and AE. Currently there is no alternative drug to albendazole to treat echinococcosis, and new compounds are required urgently. Recently acquired genomic and proteomic information can provide a platform for improving diagnosis and for finding new drug and vaccine targets, with direct impact in the future on the control of echinococcosis, which continues to be a global challenge.

Estimating the prevalence of Echinococcus in domestic dogs in highly endemic for echinococcosis

BACKGROUND

Cystic echinococcosis (CE) and alveolar echinococcosis (AE) are highly endemic in Xiji County of Ningxia Hui Autonomous Region (NHAR) in China where the control campaign based on dog de-worming with praziquantel has been undertaken over preceding decades. This study is to determine the current prevalence of Echinococcus granulosus and E. multilocularis in domestic dogs and monitor the echinococcosis transmission dynamics.

METHODS

Study villages were selected using landscape patterns (Geographic Information System, GIS) for Echinococcus transmission "hot spots", combined with hospital records identifying risk areas for AE and CE. A survey of 750 domestic dogs, including copro-sampling and owner questionnaires, from 25 selected villages, was undertaken in 2012. A copro-multiplex PCR assay was used for the specific diagnosis of E. granulosus and E. multilocularis in the dogs. Data analysis, using IBM SPSS Statistics, was undertaken, to compare the prevalence of the two Echinococcus spp. in dogs between four geographical areas of Xiji by the χ2 test. Univariate analysis of the combinations of outcomes from the questionnaire and copro-PCR assay data was carried out to determine the significant risk factors for dog infection.

RESULTS

The highest de-worming rate of 84.0% was found in the northwest area of Xiji County, and significant differences (P <  0.05) in the de-worming rates among dogs from the four geographical areas of Xiji were detected. The highest prevalence (19.7%, 59/300) of E. multilocularis occurred in northwest Xiji, though the highest prevalence (18.1%, 38/210) of E. granulosus occurred in southwest Xiji. There was no significant difference (P >  0.05) in the prevalence of E. granulosus in dogs from the northwest, southwest, northeast, and southeast of Xiji, but there were significant differences (P <  0.05) between dogs infected with E. multilocularis from the four areas. None of the other independent variables was statistically significant.

CONCLUSIONS

The results from this study indicate a high prevalence of both E. granulosus and E. muiltilocularis in dogs in Xiji County, NHAR. Transmission of E. multilocularis was more impacted by geographical risk-factors in Xiji County than that of E. granulosus. Dogs have the potential to maintain the transmission of both species of Echinococcus within local Xiji communities, and the current praziquantel dosing of dogs appears to be ineffective or poorly implemented in this area.

Dog vaccination with EgM proteins against Echinococcus granulosus

Background

Dogs play a pivotal role in the transmission of cystic echinococcosis (CE), a zoonosis caused by the tapeworm Echinococcus granulosus. We showed previously that dogs vaccinated with two E. granulosus adult-worm specific proteins, EgM9 and EgM123, emulsified with Freund’s adjuvants induced significant protective efficacy in terms of reduction in worm burden and egg production after 45 days post-infection. It was not known whether this protection can be sustained using adjuvants suitable for use in dogs.

Methods

Recombinant EgM9 and EgM123 were mixed with Quil A or ISCOMs for vaccinating dogs. After three vaccine injections, all the dogs were orally challenge-infected with 200 000 protoscoleces of E. granulosus. After 45 days of infection, all the dogs were euthanized and necropsied for collecting and counting E. granulosus worms. Immunoglobins, including the IgG subclasses IgG1 and IgG2, were detected in the sera of vaccinated dogs by ELISA. To determine whether the protection efficacy could be maintained after 45 days post-infection, we implemented a longevity trial to count eggs in dog faeces for 170 days after infection.

Results

The dogs vaccinated with EgM9 and EgM123 mixed with Quil A and ISCOMs showed similar protective efficacy as the proteins emulsified with Freund’s adjuvants in our previous study in terms of reduction of worms and eggs at 45 days post-infection. The longevity trial showed that EgM9 protein-vaccinated group released lower number of eggs per gram compared with the egg counts in the control dogs during the dog trial study.

Conclusion

EgM9 and EgM123 are thus suitable vaccine candidates against E. granulosus infection in dogs.

Electronic supplementary material

The online version of this article (10.1186/s40249-018-0425-4) contains supplementary material, which is available to authorized users.

Global phylogeography and genetic diversity of the zoonotic tapeworm Echinococcus granulosus sensu stricto genotype G1

Echinococcus granulosus sensu stricto (s.s.) is the major cause of human cystic echinococcosis worldwide and is listed among the most severe parasitic diseases of humans. To date, numerous studies have investigated the genetic diversity and population structure of E. granulosus s.s. in various geographic regions. However, there has been no global study. Recently, using mitochondrial DNA, it was shown that E. granulosus s.s. G1 and G3 are distinct genotypes, but a larger dataset is required to confirm the distinction of these genotypes. The objectives of this study were to: (i) investigate the distinction of genotypes G1 and G3 using a large global dataset; and (ii) analyse the genetic diversity and phylogeography of genotype G1 on a global scale using near-complete mitogenome sequences. For this study, 222 globally distributed E. granulosus s.s. samples were used, of which 212 belonged to genotype G1 and 10 to G3. Using a total sequence length of 11,682 bp, we inferred phylogenetic networks for three datasets: E. granulosus s.s. (n = 222), G1 (n = 212) and human G1 samples (n = 41). In addition, the Bayesian phylogenetic and phylogeographic analyses were performed. The latter yielded several strongly supported diffusion routes of genotype G1 originating from Turkey, Tunisia and Argentina. We conclude that: (i) using a considerably larger dataset than employed previously, E. granulosus s.s. G1 and G3 are indeed distinct mitochondrial genotypes; (ii) the genetic diversity of E. granulosus s.s. G1 is high globally, with lower values in South America; and (iii) the complex phylogeographic patterns emerging from the phylogenetic and geographic analyses suggest that the current distribution of genotype G1 has been shaped by intensive animal trade.