Assessment of a 10-year dog deworming programme on the transmission of Echinococcus multilocularis in Tibetan communities in Sichuan Province, China

Presence of Echinococcus eggs in the environment and food: a review of current data and future prospects

Cystic and alveolar echinococcosis are considered the second and third most significant foodborne parasitic diseases worldwide. The microscopic eggs excreted in the feces of the definitive host are the only source of contamination for intermediate and dead-end hosts, including humans. However, estimating the respective contribution of the environment, fomites, animals or food in the transmission of Echinococcus eggs is still challenging. Echinococcus granulosus and E. multilocularis seem to have a similar survival capacity regarding temperature under laboratory conditions. In addition, field experiments have reported that the eggs can survive several weeks to years outdoors, with confirmation of the relative susceptibility of Echinococcus eggs to desiccation. Bad weather (such as rain and wind), invertebrates and birds help scatter Echinococcus eggs in the environment and may thus impact human exposure. Contamination of food and the environment by taeniid eggs has been the subject of renewed interest in the past decade. Various matrices from endemic regions have been found to be contaminated by Echinococcus eggs. These include water, soil, vegetables and berries, with heterogeneous rates highlighting the need to acquire more robust data so as to obtain an accurate assessment of the risk of human infection. In this context, it is essential to use efficient methods of detection and to develop methods for evaluating the viability of eggs in the environment and food.

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.

Arecoline induces neurotoxicity in HT22 cells via the promotion of endoplasmic reticulum stress and downregulation of the Nrf2/HO-1 pathway

Arecoline, the predominant bioactive substance extracted from areca nut (AN), is the world's fourth most frequently used psychoactive material. Research has revealed that chewing AN can affect the central nervous system (CNS) and may lead to neurocognitive deficits that are possibly linked to the action of arecoline. However, the mechanism behind the neurotoxicity caused by arecoline remains unclear. This study aimed to investigate the neurotoxic effects of arecoline and its underlying mechanism. The results showed that arecoline caused cytotoxicity against HT22 cells in a dose-dependent manner and induced apoptosis by upregulating the expression of pro-apoptotic caspase and Bcl-2 family proteins. Furthermore, arecoline escalated intracellular reactive oxygen species (ROS) levels and Ca2+ concentration with increasing doses, thereby motivating endoplasmic reticulum stress (ERS) and ERS-associated apoptotic protein expression. Additionally, the study found that arecoline attenuates intracellular antioxidant defense by inhibiting the translocation of NF-E2-related factor-2 (Nrf2) into the nucleus and decreasing downstream Heme oxygenase-1 (HO-1) levels. The specific inhibitor Sodium 4-phenylbutyrate (4-PBA) can dramatically attenuate arecoline-mediated cell apoptosis and ERS-associated apoptotic pathway expression by blocking ERS. The antioxidant N-Acetylcysteine (NAC) also effectively reverses the arecoline-mediated increase of ERS-related apoptotic pathway protein levels by scavenging intracellular ROS accumulation. In conclusion, this study suggests that arecoline induces neurotoxicity in HT22 cells via ERS mediated by oxidative stress- and Ca2+ disturbance, as well as by downregulation of the Nrf2/HO-1 pathway.

Prevalence of Intestinal Parasites in Dog Faecal Samples from Public Environments in Qinghai Province, China

Dogs are popular companions in our daily lives for company, hunting, protection or shepherding, but they also serve as reservoirs for zoonotic parasites. We analysed faecal samples from urban and rural environments in Qinghai Province on the Qinghai-Tibet Plateau of China to determine the prevalence of intestinal parasites. A total of 682 faecal samples were collected from four urban and two rural environments from October 2019 to December 2020. The samples were analysed for common intestinal parasites using a species-specific PCR approach. The total number of samples with parasites was 40 (5.87%): 23 (3.37%) were positive for helminths, and 17 (2.49%) were positive for protozoa. The following parasites were identified, and their respective prevalence rates were calculated: Cryptosporidium canis (1.32%), Giardia duodenalis (1.17%, assemblages D (n = 6) and C (n = 2)), Taenia hydatigena (1.03%), Taenia multiceps (0.59%), Toxocara canis (0.59%), Echinococcus shiquicus (0.29%), Dipylidium caninum (0.29%), Taenia pisiformis (0.15%), Mesocestoides lineatus (0.15%), Trichuris vulpis (0.15%), and Ancylostoma spp. (0.15%). The overall prevalence was significantly higher in dog faecal samples from rural environments than in those from urban environments (16.19% vs. 3.99%). E. shiquicus, T. pisiformis, M. lineatus, T. vulpis, and Ancylostoma spp. were only found in dog faecal samples from rural environments. The results of the present study indicate that intestinal parasite-positive dogs are important sources of environmental contamination, suggesting a significant zoonotic infection risk in humans and other animals. This has implications for the ongoing control of intestinal parasite infections in dogs in Qinghai Province, China.

Geographical Detector-based influence factors analysis for Echinococcosis prevalence in Tibet, China

Echinococcosis, caused by genus Echinococcus, is the most pathogenic zoonotic parasitic disease in the world. In Tibet of the People's Republic of China, echinococcosis refers principally to two types of severe zoonosis, cystic echinococcosis (CE) and alveolar echinococcosis (AE), which place a serious burden on public health and economy in the local community. However, research on the spatial epidemiology of echinococcosis remains inadequate in Tibet, China. Based on the recorded human echinococcosis data, maps of the spatial distribution of human CE and AE prevalence in Tibet were produced at city level and county level respectively, which show that the prevalence of echinococcosis in northern and western Tibet was much higher than that in other regions. We employ a geographical detector to explore the influencing factors for causing CE and AE while sorting information on the maps of disease prevalence and environment factors (e.g. terrain, population, and yak population). The results of our analysis showed that biological factors have the most impact on the prevalence of echinococcosis, of which the yak population contributes the most for CE, while the dog population contributes the most for AE. In addition, the interaction between various factors, as we found out, might further explain the disease prevalence, which indicated that the echinococcosis prevalence is not simply affected by one single factor, but by multiple factors that are correlated with each other complicatedly. Our results will provide an important reference for the evaluation of the echinococcosis risk, control projects, and prevention programs in Tibet.