Advances in the treatment, diagnosis, control and scientific understanding of taeniid cestode parasite infections over the past 50 years

Extracts and Terpenoids from Stevia Species as Potential Anthelmintics for Neglected Tropical Diseases Caused by Cestode Parasites

Cestodes are etiological agents of neglected diseases such as echinococcosis and cysticercosis, which are major public health problems. Antiparasitic treatment relies on a small number of approved drugs, which are often only partially effective, poorly tolerated and require prolonged administration. Thus, the discovery of novel potential treatments is critical. The Stevia genus (Asteraceae) includes species that are recognized as a source of bioactive compounds, with many species associated with medicinal uses. In this study, the cestocidal activity of four South American Stevia species that previously showed antiprotozoal activity was analyzed using a motility assay on the laboratory cestode model, Mesocestoides vogae. The four Stevia extracts showed cestocidal activity, with S. alpina var. alpina as the most active. The sesquiterpene lactones estafietin and eupatoriopicrin were purified from S. alpina var. alpina and S. maimarensis, respectively, and tested on M. vogae. Estafietin showed cestocidal activity, inhibiting parasite viability in a dose-dependent manner, even from the first day of incubation. Consistent with the motility effects, the extract of S. alpina var. alpina and estafietin induced marked alterations in the morphology of the parasite. The results of this report show that Stevia species represent a source of new molecules with potential for the treatment of neglected tropical diseases caused by cestodes.

Evaluation of the In-Vitro Effects of Albendazole, Mebendazole, and Praziquantel Nanocapsules against Protoscolices of Hydatid Cyst

Cystic echinococcosis still remains a serious health and economic problem worldwide. The etiologic agent is Echinococcus granulosus sensu lato, giving origin to a fluid-filled cystic lesion. Therapy faces several challenges. Nanodrugs have shown promise as chemotherapeutics against hydatid cysts. The present study evaluated a highly safe lipid nano-polymeric capsule for its superior efficacy and ability to overcome drug resistance. Nanocapsule drugs were formulated into six groups: Albendazole, mebendazole, praziquantel, albendazole + mebendazole, albendazole + praziquantel, and praziquantel + mebendazole. The protoscolicidal effects of these six groups were assessed at 10, 60, and 120 min in three concentrations (1, 0.5, and 0.25 mg/mL). Drug formulations were evaluated via zeta potential, droplet size, solubility, particle size analyzer (PSA), and scanning electron microscopy. According to the PSA results, the mean size of the albendazole nanocapsules was 193.01 nm, mebendazole was 170.40 nm, and praziquantel was 180.44 nm. Albendazole + mebendazole showed the greatest protoscolicidal activity at a concentration of 1 mg/mL after 120 min. In contrast, each drug's 0.25 mg/mL single-dose times showed the least protoscolicidal activity after 120 min. With the right application of nanotechnology, it is possible to produce safe and effective drugs, such as the polymeric combination of albendazole and mebendazole, which has promising implications.

Anti-echinococcal effect of metformin in advanced experimental cystic echinococcosis: reprogrammed intermediary carbon metabolism in the parasite

Metformin, a safe biguanide derivative with antiproliferative properties, has shown antiparasitic efficacy against the Echinococcus larval stage. Hence, we assessed the efficacy of a dose of 250 mg kg-1 day-1 in experimental models of advanced CE, at 6 and 12 months post-infection with oral and intraperitoneal administration, respectively. At this high dose, metformin reached intracystic concentrations between 0.7 and 1.7 mM and triggered Eg-TOR inhibition through AMPK activation by AMP-independent and -dependent mechanisms, which are dependent on drug dose. Cystic metformin uptake was controlled by increased expression of organic cation transporters in the presence of the drug. In both experimental models, metformin reduced the weight of parasite cysts, altered the ultrastructural integrity of their germinal layers, and reduced the intracystic availability of glucose, limiting the cellular carbon and energy charge and the proliferative capacity of metacestodes. This glucose depletion in the parasite was associated with a slight increase in cystic uptake of 2-deoxiglucose and the transcriptional induction of GLUT genes in metacestodes. In this context, drastic glycogen consumption led to increased lactate production and altered intermediary metabolism in treated metacestodes. Specifically, the fraction of reducing soluble sugars decreased twofold, and the levels of non-reducing soluble sugars, such as sucrose and trehalose, were modified in both cystic fluid and germinal cells. Taken together, our findings highlight the relevance of metformin as a promising candidate for CE treatment and warrant further research to improve the therapeutic conditions of this chronic zoonosis in humans.

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.

Epidemiological update of cystic echinococcosis in livestock and assessment of practices related to its control in the Mediterranean area

Cystic echinococcosis (CE), caused by the tapeworm Echinococcus granulosus, is a zoonotic parasitic disease that still represents a serious threat to human and animal health worldwide. The Mediterranean basin is recognized as one of the major hotspots of CE due to several factors, including the presence of diverse intermediate host species as well as socio-economic and cultural conditions of local communities. This study aims to take a closer look at epidemiological data on CE in the Mediterranean area and assess the knowledge attitudes and practices of shepherds towards this disease in four countries (Algeria, Greece, Italy and Tunisia), highly endemic for CE, with the final goal of identifying highly endemic risk areas and practices in use which might potentially allow the persistence of E. granulosus infection in these areas. To update the epidemiological scenario of CE in Mediterranean areas, a comprehensive review of peer-reviewed literature on CE prevalence data published during the 2017-2023 period was carried out and, through a geographical information system (GIS), a map displaying the current CE distribution in the Mediterranean area was generated. In addition, a questionnaire survey was conducted through in-depth interviews of the farmers to collect information on their management system as well as knowledge attitudes and practices towards CE. From the farmer-participatory survey some risky practices emerged including the non-regular deworming of dogs or the use of ineffective drugs or dosing, as well as the provision of uncooked animal viscera to dogs. Finally, lower levels of knowledge and awareness of the disease was observed among farmers from North Africa compared with those of European countries. In conclusion, the results obtained highlight that CE is still a very serious problem in Mediterranean areas and increased efforts are needed to promote awareness among farmers and to turn research results into policy in order to reduce the spread of this disease, according to the One Health perspective.

Baiting not-owned dogs against Echinococcus granulosus: innovative tools for integrated control

Cystic echinococcosis (CE), caused by the larval stage of the cestode Echinococcus granulosus, is one of the most widespread zoonoses in Mediterranean countries. Baiting not-owned dogs with praziquantel (PZQ), due to their key role in the maintaining the transmission of CE, currently appears to be the most effective way to limit the transmission of CE, as well as an important aspect to introduce for the control of this parasitic disease. Therefore, this study aims to test 3 types of PZQ-based baits by evaluating different parameters (integrity over time, attractiveness and palatability for dogs, and mechanical resistance after release to different altitudes) and the bait acceptance in field by target animals, i.e. not-owned dogs, by using camera traps. The double PZQ-laced baits (with a double layer of highly palatable chews) showed the greatest resistance in the environment while also preserving the attractiveness and palatability up to 10 days, also withstood heights of 25 m, thus resulting as the most suitable also for drone delivery. The results on the field showed that most of the baits were consumed by not-owned dogs (82.2%), while the remaining were consumed by wild boars (8.9%), foxes (6.7%), badgers (1.1%) and hedgehogs (1.1%), confirming the specific and high attractiveness of the double PZQ-laced baits for the target population and highlights how an anthelmintic baiting programme may be a viable tool for the management of E. granulosus among free-ranging dog populations in endemic rural areas.

The effect of hydatid cyst protoscolex somatic antigens on full-thickness skin wound healing in mouse

BACKGROUND

Wound healing has evolved in recent years, resulting in diverse therapeutic options.

OBJECTIVE

This study evaluated the effects of the somatic antigen of the hydatid cyst protoscolex on wound healing in mice with full-thickness skin wounds.

METHODS

Fifty-four adult mice, weighing 25 ± 5 g and approximately 60 days old, were divided into three groups (A, B, and C), each further divided into three subgroups. Subgroups A1, A2, and A3 were assigned negative controls. B1, B2, and B3 received hydatid cyst somatic antigen tests at 10 µg/SC, whereas C1, C2, and C3 received somatic antigen tests at 20 µg/SC. Under general anesthesia, a wound biopsy puncture of 9.8 mm in diameter was performed on the mice's back and spine. In the experimental group, antigen and alum adjuvant were administered subcutaneously around the wound, while the control group received Phosphate-Buffered Saline (PBS). Using digital images, a geometric assessment was conducted on days 0, 1, 3, 6, 9, 12, 15, 18, and 21 post-wounding. The obtained images were analyzed by Image J software and after analyzing the data by SPSS software.

RESULTS

A significant difference in terms of epithelization was observed in the antigen treatment group with a dose of 20 µg on days 3 and 6 (P < 0.05). Furthermore, the 20 µg antigen group was significantly higher than the 10 µg antigen group in terms of this factor on day 3 (P < 0.05). Skin samples were taken from all wounds on days 3, 10 and 21 for microscopic evaluation. Regarding epithelization, on day 10, a significant difference was observed in the treatment group with a concentration of 10 µg with the control group and the treatment group with a concentration of 20 µg (P < 0.05).

CONCLUSION

Based on the results of the present study, it can be concluded that somatic antigens of protoscolex hydatid cyst are dose-dependent and antigens with a dose of 20 µg by subcutaneous injection accelerate wound healing and epithelialization.

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.

Serological Comparison of Native Antigen ELISAs with Rapid ICT Test Kits for the Diagnosis of Human Alveolar and Cystic Echinococcosis in China

BACKGROUND

The aim of this study was to compare the diagnostic performance of native antigen ELISAs and ADAMU-AE/CE commercial ICT test kits in subjects either exposed to Echinococcus infection or with clinically diagnosed alveolar (AE) or cystic (CE) echinococcosis.

METHODS

A total of 370 subjects with a previous clinical confirmation of CE or AE from northwestern China were recruited. Serum samples were also obtained from 3923 children/teenagers during a community survey. All sera were tested using native antigen ELISAs. The ADAMU-AE/CE test kits were subsequently used for the serology of the 370 clinically confirmed individuals and of 251 children/teenagers that were ELISA antibody-positive for both Echinococcus species but ultrasound-negative during baseline survey. An analysis of the association between the serological tests and ultrasound classification was carried out amongst 89 AE and 164 CE cases. A Kappa consistency analysis was undertaken to compare the diagnostic performance of the native antigen ELISAs and the ADAMU kits and the ultrasound imaging results. The χ² test was also used for a comparison of the different seropositivity rates between the groups.

FINDINGS

There was poor consistency (Kappa = 0.26 and 0.28 for AE and CE respectively) between the native antigen ELISAs and the ADAMU kits for the diagnosis of AE and CE among the cases and the surveyed children/teenagers, but a relatively good consistency (Kappa = 0.63) between the ADAMU-AE kit and ultrasound observations for the AE cases. Additionally, of the 251 teenagers co-positive for both AE and CE antibodies by the native antigen ELISAs, only one was found positive by the ADAMU-AE kit, verified as a new AE case on subsequent ultrasound follow-up. The remainder (N = 250) were negative by serology using the ADAMU-AE/CE kits and by ultrasound examination. The two native antigen ELISAs did not discriminate well between cases of clinically diagnosed AE and CE. In contrast, ADAMU-AE and ADAMU-CE commercial ICT test kits readily differentiated cases of AE from CE with specificities of 99% for AE and 100% for CE.

CONCLUSIONS

The ADAMU-AE/CE kits proved reliable, accurate, and amenable diagnostic tools in the clinical setting for confirmation of suspected AE/CE cases. The native antigen ELISAs tests can provide useful information on the level of human exposure to Echinococcus infection.

Working towards the development of vaccines and chemotherapeutics against neosporosis-With all of its ups and downs-Looking ahead

Neospora caninum is an apicomplexan and obligatory intracellular parasite, which is the leading cause of reproductive failure in cattle and affects other farm and domestic animals, but also induces neuromuscular disease in dogs of all ages. In cattle, neosporosis is an important health problem, and has a considerable economic impact. To date there is no protective vaccine or chemotherapeutic treatment on the market. Immuno-prophylaxis has long been considered as the best control measure. Proteins involved in host cell interaction and invasion, as well as antigens mediating inflammatory responses have been the most frequently assessed vaccine targets. However, despite considerable efforts no effective vaccine has been introduced to the market to date. The development of effective compounds to limit the effects of vertical transmission of N. caninum tachyzoites has emerged as an alternative or addition to vaccination, provided suitable targets and safe and efficacious drugs can be identified. Additionally, the combination of both treatment strategies might be interesting to further increase protectivity against N. caninum infections and to decrease the duration of treatment and the risk of potential drug resistance. Well-established and standardized animal infection models are key factors for the evaluation of promising vaccine and compound candidates. The vast majority of experimental animal experiments concerning neosporosis have been performed in mice, although in recent years the numbers of experimental studies in cattle and sheep have increased. In this review, we discuss the recent findings concerning the progress in drug and vaccine development against N. caninum infections in mice and ruminants.

Prevalence of cystic echinococcosis among livestock in pastoral and agro-pastoral areas in Uganda

Cystic echinococcosis (CE) remains a significant challenge in Uganda with precise status largely undocumented in most communities. To determine CE prevalence, post-mortem examination was done on 14 937 livestock (5873 goats, 1377 sheep, 3726 zebu cattle and 3054 Ankole cattle) slaughtered in abattoirs in the districts of Moroto in Karamoja region, Kumi in Teso region and Nakasongola and Luwero in Buganda region. The overall CE prevalence was 21.9% in sheep, 15.2% in zebu cattle, 5.5% in goats and 2.1% in Ankole cattle. Moroto district had a higher prevalence of CE than other districts with 31.3% in zebu cattle, sheep 28%, goats 29.1% and (0%) in Ankole cattle. On organ locations, the lungs were the most affected in all livestock in all the study areas. Considering cyst fertility, 33.9, 1.7 and 6.4% of Ankole cattle, sheep and zebu cattle respectively had fertile cysts in the liver while 4.5% of goats and 4% Ankole cattle had fertile cysts in the lungs. In conclusion, CE is widespread and occurs among cattle, sheep and goats in pastoral and agro-pastoral areas in Uganda. Therefore, there is an urgent need to create awareness among the communities on role of livestock in CE epidemiology and transmission.

Challenges and Prospective of Enhancing Hydatid Cyst Chemotherapy by Nanotechnology and the Future of Nanobiosensors for Diagnosis

Hydatid cysts have been widely recognized for decades as a common medical problem that affects millions of people. A revolution in medical treatment may be on the prospect of nanotechnology enhancing chemotherapy against hydatid cysts. An overview of nanotechnology's impact on chemotherapeutics is presented in the current review. It discusses some of the challenges as well as some of the opportunities. The application of nanotechnology to enhance chemotherapy against hydatid cysts is what this review will explore. Nanotechnology is a critical component of delivering therapeutic agents with greater precision and efficiency and targeting hydatid cysts with better efficacy, and minimizing interference with surrounding tissue. However, there are biodistribution challenges, toxicity, and resistance problems associated with nanotherapeutics. Additionally, nanobiosensors are being investigated to enable the early diagnosis of hydatid cysts. A nanobiosensor can detect hydatid cysts by catching them early, non-invasively, rapidly, and accurately. The sensitivity and specificity of diagnostic tests can be enhanced with nanobiosensors because they take advantage of the unique properties of nanomaterials. By providing more precise and customized treatment options for hydatid cysts, nanotechnology may improve therapeutic options and strategies for diagnosing the disease. In conclusion, treatment with nanotechnology to treat hydatid cysts is potentially effective but presents many obstacles. Furthermore, nanobiosensors are being integrated into diagnostic techniques, as well as helping to diagnose patients earlier and more accurately.

Watch-and-wait approach for inactive echinococcal cysts: scoping review update since the issue of the WHO-IWGE Expert Consensus and current perspectives

PURPOSE OF REVIEW

This work aims to provide an update of knowledge on the evolution of inactive cystic echinococcosis (CE) cysts (CE4-CE5) managed by 'watch-and-wait', by means of a scoping review of the literature published after the publication of the WHO-IWGE (Informal Working Group on Echinococcosis) Expert Consensus document in 2010.

RECENT FINDINGS

A total of 31 articles were included. Population ultrasound-based studies showed that spontaneously inactivated CE cysts represent 50.2% (95% confidence interval 38.7-61.8) of all detected untreated CE cysts, and that the prevalence of CE4-CE5 cysts tends to increase with age. Four longitudinal population-based studies showed that CE cysts naturally tend to evolve towards inactivation and that spontaneously inactivated cysts reactivate in a minority of cases. This was confirmed by four hospital-based studies, showing that spontaneously inactivated cysts reactivate rarely, while rate of reactivation is higher if inactivity was obtained posttreatment. It was not possible to drive conclusions on any difference in the clinical course of infection in immunocompromised or pregnant patients.

SUMMARY

CE cysts tend to evolve spontaneously to inactivation over time. The published literature supports the safety of the watch-and-wait approach for inactive cysts, sparing treatment to a substantial proportion of asymptomatic patients. A regular follow-up with ultrasound of all inactive cysts is required to detect reactivations.

'No cyst, no echinococcosis': a scoping review update on the diagnosis of cystic echinococcosis after the issue of the WHO-IWGE Expert Consensus and current perspectives

PURPOSE OF REVIEW

In 2010, the WHO-Informal Working Group on Echinococcosis (IWGE) published an Expert Consensus on the diagnosis and treatment of echinococcal infections. We provide an update on the diagnosis of cystic echinococcosis through a scoping review of the literature published after the release of the WHO-IWGE document.

RECENT FINDINGS

Ultrasound accurately and reliably depicts the pathognomonic signs of cystic echinococcosis (CE) stages compared with other imaging techniques. Among these, T2-wighted MRI is to be preferred to computed tomography, which has poor performance for the etiological diagnosis of CE. A negative serology cannot exclude the diagnosis of CE, while a positive serology, applied after the visualization of a CE-compatible lesion, may confirm a CE diagnosis. Serology alone must not be used to define 'CE' nor as 'screening' tool for infection. Other imaging and laboratory techniques did not show clinically applicable performances.

SUMMARY

In the absence of a focal lesion compatible with a CE cyst, no diagnosis of CE should be attempted. There is urgent need to achieve univocal CE case definitions and consensus diagnostic algorithm, as well as standardization of diagnostic methods and issue of a Target Product Profile of CE diagnostics, as advocated by the WHO in the 2021-2030 roadmap for neglected tropical diseases (NTDs).

EgSeverin and Eg14-3-3zeta from Echinococcus granulosus are potential antigens for serological diagnosis of echinococcosis in dogs and sheep

Cystic echinococcosis (CE) is a zoonotic parasitic disease caused by the metacestode larva of Echinococcus granulosus. In this study, two-dimensional gel electrophoresis (2-DE) coupled with immunoblot analysis revealed that E. granulosus severin and 14-3-3zeta proteins (named EgSeverin and Eg14-3-3zeta, respectively) might be two potential biomarkers for serological diagnosis of echinococcosis. The recombinant EgSeverin (rEgSeverin, 45 kDa) and Eg14-3-3zeta (rEg14-3-3zeta, 35 kDa) were administered subcutaneously to BALB/c mice to obtain polyclonal antibodies for immunofluorescence analyses (IFAs). And IFAs showed that both proteins were located on the surface of protoscoleces (PSCs). Western blotting showed that both proteins could react with sera from E. granulosus-infected sheep, dog, and mice. Indirect ELISAs (rEgSeverin- and rEg14-3-3zeta-iELISA) were developed, respectively, with sensitivities and specificities ranging from 83.33% to 100% and a coefficient of variation (CV %) of less than 10%. The rEgSeverin-iELISA showed cross-reaction with both E. granulosus and E. multilocularis, while the rEg14-3-3zeta-iELISA showed no cross-reaction with other sera except for the E. granulosus-infected ones. The field sheep sera from Xinjiang and Qinghai were analyzed using rEgSeverin-iELISA, rEg14-3-3zeta-iELISA, and a commercial kit respectively, and no significant differences were found among the three methods (p > 0.05). However, the CE positive rates in sheep sera from Qinghai were significantly higher than those from Xinjiang (p < 0.01). Overall, the results suggest that EgSeverin and Eg14-3-3zeta could be promising diagnostic antigens for E. granulosus infection.

Immunogenicity of peptide-based vaccine composed of epitopes from Echinococcus granulosus rEg.P29

Echinococcus granulosus is one of the main causes of economic loss in the livestock industry because of its food-borne transmission. Cutting off the transmission route is a valid prevention method, and vaccines are the most effective means of controlling and eliminating infectious diseases. However, no human-related vaccine has been yet marketed. As a genetic engineering vaccine, recombinant protein P29 of E. granulosus (rEg.P29) could provide protection against deadly challenges. In this study, we generated peptide vaccines (rEg.P29_T , rEg.P29_B , and rEg.P29_T+B ) based on rEg.P29 and an immunized model was established by subcutaneous immunization. Further evaluation showed that peptide vaccine immunization in mice induced T helper type 1 (Th1)-mediated cellular immune responses, leading to high levels of rEg.P29 or rEg.P29_B -specific antibodies. In addition, rEg.P29_T+B immunization can induce a higher antibody and cytokine production level than single-epitope vaccines, and immune memory is also longer. Collectively, these results suggest that rEg.P29_T+B has the potential to be developed as an efficient subunit vaccine for use in areas where E. granulosus is endemic.

Comparison of multiplex copro PCR with coproscopy followed by PCR on recovered eggs for the detection of Echinococcus granulosus and Taenia spp. infection in dogs

Echinococcosis and taeniasis are important helminth diseases that carry considerable impact on human and animal health. Domestic dogs and other canids are definitive hosts for several parasites of this group, including Echinococcus granulosus, Taenia multiceps, T. ovis, T. hydatigena and E. multilocularis. Detection of infection in dog populations is imperative for estimating the risk to susceptible humans and animals, and for its mitigation through prevention measures in dogs, other animals and humans. To date, identification of taeniid eggs, antigens or DNA in fecal samples are the most practical diagnostic modalities available for canine definitive hosts. Although widely used for this purpose, there is limited information comparing copro PCR and combined coproscopy-PCR protocols for the detection of taeniids. In the current study, a widely used multiplex PCR was performed on a large number of dog fecal samples using DNA extracted directly from feces. The samples were also tested by fecal flotation and coproscopy, eggs were isolated from microscopically-positive samples and extracted DNA was tested using the same multiplex PCR. The total number of taeniid positive samples detected using both methods was 46/317 (14.5%), including 10/317 (3.2%) E. granulosus positive samples. Both copro PCR and coproscopy have identified an equal number of samples as taeniid positive (n = 32). However, for the purpose of identification to species level, the copro PCR was significantly more sensitive than coproscopy followed by PCR on isolated eggs (sensitivity 0.7 vs. 0.41, p = 0.012), with 32/317 (10.1%) and 19/317 (6%) positive samples identified, respectively. The difference in identification of E. granulosus was highly apparent, as the majority of the E. granulosus positive samples (8/10) were detected by the copro PCR only. Coproscopy and egg PCR have identified 5/317 (1.6%) positive samples not detected by the copro PCR, including only a single sample (0.3%) positive for E. granulosus. Adding these positive samples to those identified by the copro PCR did not significantly improve the overall sensitivity (p = 0.074). Therefore, using both copro PCR and coproscopy in parallel may not be advantageous for taeniid detection and identification, at least until the egg PCR is further optimized and performs better. These results should be weighed against the different advantages that coproscopy based approach may offer.

Alterations in Gut Microbiota Profiles of Mice Infected with Echinococcus granulosus sensu lato Microbiota Profiles of Mice Infected with E. granulosus s.l

OBJECTIVE

Cystic echinococcosis is a kind of parasitic disease that seriously endangers human and animal health. At present, its prevention and treatment still do not achieve the desired results. The aims of this study were to explore the effect of CE on intestinal microflora in mice.

METHODS

In this study, 16S rRNA metagenome sequencing and bioinformatics were used to analyze the intestinal flora of mice infected with E. granulosus s.l. Changes in intestinal microbial community abundance were investigated and the differences in microbial populations of mice infected with E. granulosus s.l. were screened.

RESULTS

Our results show that at the phylum level, nine abundant taxa were identified, the relative abundance of Firmicutes and Proteobacteria were enriched in infected mice, whereas Bacteroidetes and Patescibacteria were enriched in control mice (P < 0.01). At the class level, 13 abundant taxa were identified, the relative abundance of Bacilli was enriched in control mice, but decreased in infected mice (P < 0.01). At the order level, 15 abundant taxa were identified, the relative abundance of Lactobacillales was enriched in control mice, but decreased in infected mice (P < 0.01). At the family level, 28 abundant taxa were identified, enriched bacteria in the infected mice was Streptococcaceae, while the enriched bacteria in the control group was Lactobacillaceae (P < 0.01). At the genus level, 79 abundant taxa were identified, enriched bacteria in the infected mice was Streptococcus, while the enriched bacteria in the control group was uncultured_bacterium_f_Eggerthellaceae (P < 0.01). At the species level, 80 abundant taxa were identified, enriched bacteria in the infected mice was uncultured_bacterium_g_Streptococcus, while the enriched bacteria in the control group was uncultured_bacterium_f_Eggerthellaceae (P < 0.01). 39 KEGG pathways were identified that were differentially enriched between the infected and control mice.

CONCLUSION

This study comprehensively demonstrates the differential intestinal microbiota of infected mice and analyzes the metabolic pathways related to the specific microbiota. This could provide new targets and research direction for the treatment and prevention of diseases caused by E. granulosus s.l.

Managing host-parasite interactions in humans and wildlife in times of global change

Global change in the Anthropocene has modified the environment of almost any species on earth, be it through climate change, habitat modifications, pollution, human intervention in the form of mass drug administration (MDA), or vaccination. This can have far-reaching consequences on all organisational levels of life, including eco-physiological stress at the cell and organism level, individual fitness and behaviour, population viability, species interactions and biodiversity. Host-parasite interactions often require highly adapted strategies by the parasite to survive and reproduce within the host environment and ensure efficient transmission among hosts. Yet, our understanding of the system-level outcomes of the intricate interplay of within host survival and among host parasite spread is in its infancy. We shed light on how global change affects host-parasite interactions at different organisational levels and address challenges and opportunities to work towards better-informed management of parasite control. We argue that global change affects host-parasite interactions in wildlife inhabiting natural environments rather differently than in humans and invasive species that benefit from anthropogenic environments as habitat and more deliberate rather than erratic exposure to therapeutic drugs and other control efforts.

Cystic echinococcosis in northern Tanzania: a pilot study in Maasai livestock-keeping communities

Background

There are close similarities between the life-cycles of Echinococcus granulosus sensu lato (E. granulosus s.l.) that causes cystic echinococcosis (CE) in humans and Taenia multiceps/Coenurus cerebralis that causes cerebral coenurosis in small ruminants. Recent evidence highlights that livestock in Maasai communities of northern Tanzania are suffering from increases in the prevalence of cerebral coenurosis, leading to concerns about a possible concurrent increased risk of human CE. The aim of this study was to estimate the prevalence of human abdominal CE and the prevalence and species/genotypes of E. granulosus s.l. in livestock in Maasai communities.

Methods

Human CE was diagnosed by abdominal ultrasound on volunteers aged ≥ 7 years in five villages in the Longido and Ngorongoro Districts in northern Tanzania. Infection in ruminants was evaluated through inspection in local abattoirs, followed by molecular identification of one cyst per animal, with a priority for hepatic cysts, using PCR targeting of the cytochrome c oxidase I gene (COX1), followed by restriction fragment length polymorphism and multiplex PCR, and sequencing of non-E. granulosus s.l. samples.

Results

Ultrasound was performed on 823 volunteers (n = 352 in two villages in Longido District, and n = 471 in three villages of Ngorongoro). Hepatic CE cases were diagnosed only in Ngorongoro (n = 6; 1.3%), of which three had active cysts. Village-level prevalence of CE ranged between 0 and 2.4%. Of the 697 ruminants inspected, 34.4% had parasitic cysts. Molecular identification was achieved for 140 of the 219 (63.9%) cysts sampled. E. granulosus s.l. and T. hydatigena/Cysticercus tenuicollis were identified in 51.4% and 48.6%, respectively, of livestock cysts. E. granulosus s.l. was identified in livestock from both Longido (35.3% of 116 genotyped cysts) and Ngorongoro (91.2% of 34 genotyped cysts). Of the total of 72 E. granuslosus s.l. cysts identified in livestock, 87.5% were E. granulosus sensu stricto (G1–G3 genotypes), 9.7% were E. ortleppi (G5) and one cyst was E. canadensis (G6–10). The three active human cysts, which were removed surgically, were G1–G3 genotypes.

Conclusions

Multiple species/genotypes of E. granulosus s.l. are circulating in Maasai communities of northern Tanzania. Human CE was detected in villages of Ngorongoro District and a high prevalence of echinococcal cysts was observed in livestock in both districts. More precise estimation of the prevalence in this area and a better understanding of the specific risk factors for CE among Maasai communities in northern Tanzania is needed. Interventions targeting transmission routes common to both E. granulosus s.l. and T. multiceps would have dual benefits for preventing both human and livestock disease.

Graphical Abstract

Targeting Echinococcus multilocularis PIM kinase for improving anti-parasitic chemotherapy

BACKGROUND

The potentially lethal zoonosis alveolar echinococcosis (AE) is caused by the metacestode larval stage of the tapeworm Echinococcus multilocularis. Current AE treatment options are limited and rely on surgery as well as on chemotherapy involving benzimidazoles (BZ). BZ treatment, however, is mostly parasitostatic only, must be given for prolonged time periods, and is associated with adverse side effects. Novel treatment options are thus urgently needed.

METHODOLOGY/PRINCIPAL FINDINGS

By applying a broad range of kinase inhibitors to E. multilocularis stem cell cultures we identified the proto-oncogene PIM kinase as a promising target for anti-AE chemotherapy. The gene encoding the respective E. multilocularis ortholog, EmPim, was characterized and in situ hybridization assays indicated its expression in parasite stem cells. By yeast two-hybrid assays we demonstrate interaction of EmPim with E. multilocularis CDC25, indicating an involvement of EmPim in parasite cell cycle regulation. Small molecule compounds SGI-1776 and CX-6258, originally found to effectively inhibit human PIM kinases, exhibited detrimental effects on in vitro cultured parasite metacestode vesicles and prevented the formation of mature vesicles from parasite stem cell cultures. To improve compound specificity for EmPim, we applied a high throughput in silico modelling approach, leading to the identification of compound Z196138710. When applied to in vitro cultured metacestode vesicles and parasite cell cultures, Z196138710 proved equally detrimental as SGI-1776 and CX-6258 but displayed significantly reduced toxicity towards human HEK293T and HepG2 cells.

CONCLUSIONS/SIGNIFICANCE

Repurposing of kinase inhibitors initially designed to affect mammalian kinases for helminth disease treatment is often hampered by adverse side effects of respective compounds on human cells. Here we demonstrate the utility of high throughput in silico approaches to design small molecule compounds of higher specificity for parasite cells. We propose EmPim as a promising target for respective approaches towards AE treatment.

Evaluation of Serological Markers in Alveolar Echinococcosis Emphasizing the Correlation of PET-CTI Tracer Uptake with RecEm18 and Echinococcus-Specific IgG

Human alveolar echinococcosis (AE), which is caused by the cestode Echinococcus (E.) multilocularis, is an epidemiologically relevant issue in modern medicine and still poses a diagnostic and therapeutic challenge. Since diagnosis mainly relies on imaging procedures and serological testing, we retrospectively and comparatively analyzed the performance of an Echinococcus IgG screening ELISA, whole serum IgE, and two specific confirmatory ELISA platforms using the defined E. multilocularis antigens Em2-Em18 (Em2+) and recombinant Em18 (recEm18). With special emphasis on the clinical usefulness of recEm18, we correlated the laboratory results with clinical characteristics and imaging findings in a large and well-characterized cohort of N = 124 AE patients, who were followed over several years after either surgical plus subsequent pharmacological treatment or pharmacotherapy alone. All patients had routinely received PET-CTI every two years. Our data reveal strong correlations for both Echinococcus IgG and recEm18 with tracer uptake in PET-CTI and parasitic lesion size and number, suggesting additional clinical usefulness of recEm18 for certain constellations only, while IgG and Em2+ still appear reasonable and sensitive screening methods for initial diagnosis of AE. With this study, we aim to contribute to further optimizing medical care of AE patients. For instance, it might be reasonable to consider the replacement of some PET-CTI follow-ups by imaging procedures with less radiation exposure or serological means alone. Further studies that clarify the correlation of serological markers with ultrasound criteria might be particularly useful, and further retrospective as well as prospective investigations are justified in this context.