Spatial transferability of an agent-based model to simulate Taenia solium control interventions.

BACKGROUND: Models can be used to study and predict the impact of interventions aimed at controlling the spread of infectious agents, such as Taenia solium, a zoonotic parasite whose larval stage causes epilepsy and economic loss in many rural areas of the developing nations. To enhance the credibility of model estimates, calibration against observed data is necessary. However, this process may lead to a paradoxical dependence of model parameters on location-specific data, thus limiting the model's geographic transferability. METHODS: In this study, we adopted a non-local model calibration approach to assess whether it can improve the spatial transferability of CystiAgent, our agent-based model of local-scale T. solium transmission. The calibration dataset for CystiAgent consisted of cross-sectional data on human taeniasis, pig cysticercosis and pig serology collected in eight villages in Northwest Peru. After calibration, the model was transferred to a second group of 21 destination villages in the same area without recalibrating its parameters. Model outputs were compared to pig serology data collected over a period of 2 years in the destination villages during a trial of T. solium control interventions, based on mass and spatially targeted human and pig treatments. RESULTS: Considering the uncertainties associated with empirical data, the model produced simulated pre-intervention pig seroprevalences that were successfully validated against data collected in 81% of destination villages. Furthermore, the model outputs were able to reproduce validated pig seroincidence values in 76% of destination villages when compared to the data obtained after the interventions. The results demonstrate that the CystiAgent model, when calibrated using a non-local approach, can be successfully transferred without requiring additional calibration. CONCLUSIONS: This feature allows the model to simulate both baseline pre-intervention transmission conditions and the outcomes of control interventions across villages that form geographically homogeneous regions, providing a basis for developing large-scale models representing T. solium transmission at a regional level.

Insights into the diagnosis, vaccines, and control of Taenia solium, a zoonotic, neglected parasite.

Taenia solium taeniasis/cysticercosis (TSTC) is a foodborne, zoonotic neglected tropical disease affecting predominately low- and middle-income countries. Humans are definitive hosts for T. solium, whereas pigs act as intermediate hosts. Taeniasis, i.e. intestinal infection with adult T. solium in the human host, occurs through ingestion of undercooked pork infected with the larval stage (porcine cysticercosis, PCC). Human cysticercosis occurs after humans ingest T. solium eggs, acting as accidental intermediate hosts. Migration of cysticerci to the human brain results in neurocysticercosis (NCC), manifesting in a variety of clinical symptoms, most notably epilepsy. NCC is the leading cause of acquired epilepsy cases in endemic areas. PCC results in reduced pork value because of condemnation or the risk of condemnation of the meat. Available serological diagnostic tests for porcine and human cysticercosis are characterized by low sensitivity and are not cost-effective. An effective vaccine for T. solium cysticercosis in pigs has been developed, although it is not yet commercially available in all endemic countries, and still no vaccine is available for use in humans. This primer highlights the recent development in the field of diagnostic tests and vaccine production and explores possible strategies for future control and eradication of T. solium. In the absence of highly specific diagnostic tests and human vaccines, treatment of infected pigs and tapeworm carriers and prevention of disease transmission remain the principal means to interrupt the zoonotic cycle of T. solium in endemic countries.

Community knowledge, attitudes and practices related to Taenia solium taeniosis and cysticercosis in Zambia.

BACKGROUND: Several studies on Taenia solium taeniosis / cysticercosis (TSTC) have been conducted in Zambia. However, none has assessed community knowledge, attitudes and practices related to TSTC and epilepsy. METHODS: A community-based cross-sectional study was conducted between November and December 2022. The design consisted of a questionnaire-based survey conducted in each of the 25 purposely selected villages in Chiparamba Rural Health Centre (RHC) catchment area in Chipata district of the Eastern Province. RESULTS: A total of 588 participants comprising 259 (44%) males and 329 (56%) females with median age of 42 years (range 17 to 92 years) were interviewed. Awareness of the signs and symptoms of taeniosis and human cysticercosis (HCC), including transmission and prevention measures was very low. Whilst the majority had heard about epilepsy, they were not able to link HCC to epilepsy. Most participants were aware of cysticerci in pigs (PCC) including its predilection sites but were not aware of mode of transmission and prevention measures. The pork meat inspection by trained professionals was also not a common practice in the area. Risk perception of T. solium infections was thus very low. Overall knowledge, attitude and practice scores related to T. solium infections and to epilepsy were very low with median scores of 0.38 (IQR 0.25-0.54) for knowledge, 0.25 (0.25-0.50) for attitudes, and 0.31 (0.25-0.44) for practices. Males had better knowledge on TSTC (median = 0.42, p = 0.017, r = 0.098) and better practice scores (median = 0.38, p = < 0.001, r = 0.154) compared to females though the effect size was small. With regards to sanitation and hygiene washing with soap and water was reported by many but only few had a hand washing facility near their latrines. CONCLUSION: The study shows overall poor knowledge, attitudes and practices related to TSTC among the community of Chiparamba RHC in Chipata district of the Eastern Province of Zambia. This poses a serious challenge for control and elimination of T. solium infections and thus efforts to improve knowledge, attitudes and practices should be made using a One Health approach for the control and elimination of TSTC. Educational programs about TSTC transmission, signs and symptoms, prevention, management and control need to be scaled up in the study area and Zambia as a whole.

[Epidemic trend and control progress of taeniasis and cysticercosis in Henan Province].

Henan Province is one of the provinces where taeniasis and cysticercosis were historically highly prevalent, and Taenia solium is the dominant species of tapeworm. Following the concerted efforts since 1970s, the prevalence of human taeniasis and cysticercosis has been maintained at a low level in Henan Province, which facilitates the national taeniasis and cysticercosis elimination program in China. Following the implementation of the policy of aeniasis and cysticercosis elimination and classified guidance, a great success has been achieved in aeniasis and cysticercosis control in Henan Province. With continuous promotion of the opening-up policy and the Belt and Road Initiative, there are still challenges in taeniasis and cysticercosis control. This review summarizes the control progress of taeniasis and cysticercosis and proposes the challenges of taeniasis and cysticercosis control in Henan Province.

The role of cooking practices in the transmission of the foodborne parasite Taenia solium: A qualitative study in an endemic area of Southern Tanzania.

The pork tapeworm Taenia solium is a zoonotic food-borne parasite endemic in many developing countries causing human cysticercosis and taeniosis as well as porcine cysticercosis. It mainly affects the health of rural smallholder pig farmers and their communities, resulting in lower health status, reduced pork quality, and economic loss due to condemnation of pigs or low pricing of pork. This qualitative study aimed to identify key food related practices linked to consumption of pork at village level, of importance for transmission of taeniosis. We used an interpretivist-constructivist paradigm in a multiple case study of exploratory qualitative research design. Data was acquired through guided and probing interviews with 64 pork cooks, and 14 direct observations in four villages in a T. solium endemic area of Mbeya Region in the Southern Highlands of Tanzania. The study showed that the informants were members of communities of practice through their pork cooking practices, one community of practice for the restaurant cooks and one for the home cooks, learning, sharing, and distributing their cooking skills. Furthermore, the analysis showed that the pork cooks generally had some awareness of there being something undesirable in raw pork, but they had very diverse understandings of what it was, or of its potential harm. Major potential transmission points were identified in restaurants and in home kitchens. It appears that the pork cooks act according to socio-cultural and economic factors guiding them in their actions, including pressure from customers in restaurants, the family values of tradition in the home kitchens, and the culturally guided risk perception and appraisal. These practices might generate potential transmission points. Future research on interventions aimed at preventing the spread of T. solium taeniosis should recognise the importance of tradition and culture in risky food practices.

Non-local validated parametrization of an agent-based model of local-scale Taenia solium transmission in North-West Peru.

The pork tapeworm, Taenia solium, is the cause of a preventable zoonotic disease, cysticercosis, affecting both pigs and humans. Continued endemic transmission of T. solium is a major contributor of epilepsy and other neurologic morbidity, and the source of important economic losses, in many rural areas of developing countries. Simulation modelling can play an important role in aiding the design and evaluation of strategies to control or even eliminate transmission of the parasite. In this paper, we present a new agent based model of local-scale T. solium transmission and a new, non-local, approach to the model calibration to fit model outputs to observed human taeniasis and pig cysticercosis prevalence simultaneously for several endemic villages. The model fully describes all relevant aspects of T. solium transmission, including the processes of pig and human infection, the spatial distribution of human and pig populations, the production of pork for human consumption, and the movement of humans and pigs in and out in several endemic villages of the northwest of Peru. Despite the high level of uncertainty associated with the empirical measurements of epidemiological data associated with T. solium, the non-local calibrated model parametrization reproduces the observed prevalences with an acceptable precision. It does so not only for the villages used to calibrate the model, but also for villages not included in the calibration process. This important finding demonstrates that the model, including its calibrated parametrization, can be successfully transferred within an endemic region. This will enable future studies to inform the design and optimization of T. solium control interventions in villages where the calibration may be prevented by the limited amount of empirical data, expanding the possible applications to a wider range of settings compared to previous models.

Global variation in force-of-infection trends for human Taenia solium taeniasis/cysticercosis.

Infection by Taenia solium poses a major burden across endemic countries. The World Health Organization (WHO) 2021-2030 Neglected Tropical Diseases roadmap has proposed that 30% of endemic countries achieve intensified T. solium control in hyperendemic areas by 2030. Understanding geographical variation in age-prevalence profiles and force-of-infection (FoI) estimates will inform intervention designs across settings. Human taeniasis (HTT) and human cysticercosis (HCC) age-prevalence data from 16 studies in Latin America, Africa, and Asia were extracted through a systematic review. Catalytic models, incorporating diagnostic performance uncertainty, were fitted to the data using Bayesian methods, to estimate rates of antibody (Ab)-seroconversion, infection acquisition and Ab-seroreversion or infection loss. HCC FoI and Ab-seroreversion rates were also estimated across 23 departments in Colombia from 28,100 individuals. Across settings, there was extensive variation in all-ages seroprevalence. Evidence for Ab-seroreversion or infection loss was found in most settings for both HTT and HCC and for HCC Ab-seroreversion in Colombia. The average duration until humans became Ab-seropositive/infected decreased as all-age (sero)prevalence increased. There was no clear relationship between the average duration humans remain Ab-seropositive and all-age seroprevalence. Marked geographical heterogeneity in T. solium transmission rates indicate the need for setting-specific intervention strategies to achieve the WHO goals.

Improving Health Knowledge Through Provision of Free Digital Health Education to Rural Communities in Iringa, Tanzania: Nonrandomized Intervention Study.

BACKGROUND: Community health education is one of the most effective measures to increase health literacy worldwide and can contribute to the achievement of specific targets of the Sustainable Development Goal 3. Digitalized health education materials can improve health knowledge as a dimension of health literacy and play an important role in disease prevention in rural sub-Saharan settings. OBJECTIVE: The objective of this research is to assess the effect of a digital health education intervention on the uptake and retention of knowledge related to HIV/AIDS, tuberculosis (TB), and Taenia solium (neuro)cysticercosis and taeniosis in rural communities in Iringa, Tanzania. METHODS: We conducted a nonrandomized intervention study of participants aged 15 to 45 years, randomly selected from 4 villages in Iringa, Tanzania. The intervention consisted of 2 parts. After the baseline assessment, we showed the participants 3 animated health videos on a tablet computer. After a period of 6 months, free access to community information spots (InfoSpots) with an integrated digital health education platform was provided to the intervention villages. Participants in the control group did not receive the intervention. The primary outcome was the difference in disease knowledge between the intervention and control groups, 12 months after baseline. Data were collected using an open-ended questionnaire, with correct or incorrect answers before and after intervention. RESULTS: Between April and May 2019, a total of 600 participants were recruited into the intervention (n=298, 49.7%) or control (n=302, 50.3%) groups. At baseline, no statistically significant differences in knowledge of the target diseases were observed. At 12 months after intervention, knowledge about HIV/AIDS, TB, and T. solium (neuro)cysticercosis and taeniosis was 10.2% (95% CI 5.0%-15.4%), 12% (95% CI 7.7%-16.2%), and 31.5% (95% CI 26.8%-36.2%) higher in the intervention group than in the control group, respectively. In all 4 domains (transmission, symptoms, treatment, and prevention), an increase in knowledge was observed in all the 3 diseases, albeit to varying degrees. The results were adjusted for potential confounders, and the significance of the primary results was maintained in the sensitivity analysis to assess dropouts. The participants who reported using the InfoSpots in the 12-month assessment further increased their knowledge about the target diseases by 6.8% (HIV/AIDS), 7.5% (TB), and 13.9% higher mean proportion of correct answers compared with the participants who did not use the InfoSpots. CONCLUSIONS: Digital health education based on animated health videos and the use of free InfoSpots has significant potential to improve health knowledge, especially in rural areas of low- and middle-income countries. TRIAL REGISTRATION: ClinicalTrials.gov NCT03808597; https://clinicaltrials.gov/ct2/show/NCT03808597. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.2196/25128.

Knowledge, attitudes and practices related to Taenia solium cysticercosis and taeniasis in Tanzania.

BACKGROUND: Taenia solium cysticercosis/taeniasis (TSCT) is reported to be endemic in pig producing areas around the world, causing significant disease burden and economic losses. METHODS: This cross-sectional study aimed at assessing Knowledge, Attitudes and Practices (KAP) regarding TSCT in four districts, namely Mbulu, Mpwapwa, Mbinga, and Rungwe in Tanzania. Data on KAP were collected through questionnaire-based interviews and household infrastructure observations. RESULTS: Knowledge about porcine cysticercosis was good, particularly among pig keepers across the districts. Many participants had heard about the pork tapeworm (T. solium taeniasis), and the knowledge about signs/symptoms and treatment was fair, but the means of transmission and prevention measures were often unknown. Whilst most participants were familiar with epilepsy, no one knew anything about human cysticercosis and the link between cysticercosis and epileptic seizures. A similar trend is reflected through the attitudes toward the low risk perception of cysticercosis infection. Not surprisingly, the risk perception of the infection with the pork tapeworm was low too. Many participants reported not washing their hands before eating or after using the toilet which highlights potential risks for the development of human cysticercosis. Albeit nearly every participant reported using the toilet always, household observations revealed that toilets were either lacking or had no complete walls. Generally, household observations revealed a discrepancy between questionnaire answers on the one hand and the availability of toilet and handwashing facilities and the confinement of pigs on the other hand. CONCLUSION: This study demonstrates knowledge gaps and adverse practices which may hinder and/or slow down the control/elimination of T. solium in endemic countries. The study results are also useful for appropriate designing of TSCT health interventions that need to be planned carefully, taking into account the local context and designing TSCT in partnership with the local communities from the beginning to the end applying a One Health approach to allow the possible sustained and best impacts.

[Effectiveness of training on Taenia solium taeniasis and cysticercosis control knowledge among medical professionals in disease-elimination pilot areas of Henan Province].

OBJECTIVE: To investigate the changes in the awareness rate of Taenia solium taeniasis and cysticercosis control knowledge among medical professionals before and after training in Fangcheng County, a disease-elimination pilot area of Henan Province, so as to evaluate the effectiveness of the training. METHODS: Three townships in Fangcheng County were randomly selected as the study townships, including Dushu, Bowang and Yangji townships, while Erlangmiao, Yanglou and Xiaoshidian townships in the county were randomly selected as the control townships. The grassroots medical professionals in the study townships were given once training on T. solium taeniasis and cysticercosis control knowledge each year from 2016 to 2020, while those in the control townships were given no interventions. All village-level doctors and a part of township-level public health professionals were sampled from the study and control townships as intervention and control groups. The baseline and final assessments of the awareness of T. solium taeniasis and cysticercosis control knowledge were performed using questionnaire survey in intervention and control groups in 2016 and 2020, and the awareness of T. solium taeniasis and cysticercosis control knowledge was compared between the two groups. RESULTS: A total of 663 medical professionals were investigated in Fangcheng County from 2016 to 2020, including 474 participants in the intervention group and 189 participants in the control group. Results from the 2016 baseline survey showed that the awareness rate of T. solium taeniasis and cysticercosis control knowledge was 28.83% (47/163) among grassroots medical professionals in Fangcheng County, and there were no significant differences in the awareness between the intervention (32.47%, 25/77) and control groups (25.58%, 22/86) (χ2 = 0.939, P > 0.05), between men (30.50%, 43/141) and women (18.18%, 4/22) (χ2 = 1.406, P > 0.05) or between village- (31.39%, 43/137) and township-level medical professionals (15.38%, 4/26) (χ2 = 2.727, P > 0.05), while significant differences were found in the awareness rate of T. solium taeniasis and cysticercosis control knowledge among medical professionals in terms of education levels (χ2 = 8.190, P < 0.05) and duration of working experiences (χ2 = 12.617, P < 0.05), and the awareness rate of T. solium taeniasis and cysticercosis control knowledge increased with education levels among medical professionals (χ2 = 6.768, P < 0.05). Only 5.52% (9/163) of the medical professionals had a history of diagnosis and therapy of T. solium taeniasis or cysticercosis, and only 1.23% (2/163) received training on T. solium taeniasis and cysticercosis control knowledge during the past 5 years. Results from the 2020 questionnaire survey showed a higher awareness rate of T. solium taeniasis and cysticercosis control knowledge among medical professionals in the intervention group (93.55%, 116/124) than in the control group (46.60%, 48/103) (χ2 = 61.845, P < 0.05), and no significant differences were seen in the awareness rate of T. solium taeniasis and cysticercosis control knowledge among medical professionals in terms of gender, level of medical professionals, duration of working experiences or history of diagnosis/therapy of T. solium taeniasis and cysticercosis in the intervention group (χ2 = 1.089, 0.140, 0.081 and 0.453, all P values > 0.05), while there was a significant difference in the awareness rate among medical professionals with different education levels (χ2 = 36.338, P < 0.05). In addition, the awareness rate of T. solium taeniasis and cysticercosis control knowledge significantly increased among medical professionals with various chracteristics in 2020 than in 2016. CONCLUSIONS: In the low-prevalence areas of T. solium taeniasis and cysticercosis, long-term and persistent training may improve the awareness of T. solium taeniasis and cysticercosis control knowledge among grassroots medical professionals, which facilitates the timely identification of T. solium taeniasis and cysticercosis and the establishment of a sensitive disease surveillance system.

Implementation of Taenia solium control measures in Bali, Indonesia: Survey findings and a historical overview.

Historically, cysticercosis cases caused by infection with the larval stage of the Taenia solium tapeworm have occurred sporadically in Bali, with taeniasis carriers found primarily in villages located in the Kubu subdistrict of Karangasem. As Bali is a well-known tourist destination, living standards are relatively high on the island, except for an area located beneath the northeast slope of the active volcano Mt. Agung (Alt. 3031 m), which includes Kubu. Over the last 30 years, pigs originating from this area have been found with T. solium cysticerci, whereas pigs from other parts of the island have not been shown to be infected. Out of 108 individuals screened via fecal sample examination in Kubu during 2019, 3 cases of T. solium taeniasis (2.8%) were identified. There was no significant difference in taeniasis prevalence from surveys conducted in 2011-2016 (1.0%, 11/1089) (p = 0.123). Out of 110 humans and 140 pigs tested serologically in Kubu during 2019, no cases of cysticercosis were identified. This is in contrast to a seroprevalence of 4.1% (42/1025) in humans during 2011-2016 and a seroprevalence of 13.1% (43/329) in pigs during 2011-2013. Over the last decade, improved drinking water and sanitary systems have been employed in addition to health education targeting primary school children, including emphasis on washing hands before eating and after defecation. This review provides previously unpublished survey data and a historical overview of T. solium infection in Bali and offers guidance on best practices to ensure that remaining pockets of transmission are addressed.

Guideline for preventive chemotherapy for the control of Taenia solium Taeniasis

The larval stage of the parasite Taenia solium can encyst in the central nervous system causing neurocysticercosis, which is the main cause of acquired epilepsy in the countries in which the parasite is endemic. Endemic areas are those with the presence (or likely presence) of the full life cycle of Taenia solium. The parasite is most prevalent in poor and vulnerable communities in which pigs roam free, open defecation is practiced, basic sanitation is deficient, and health education is absent or limited. Several tools are available for the control of Taenia solium. Preventive chemotherapy for Taenia solium taeniasis, which is directed at the adult tapeworm, is one of them. Other tools focus on pig management, pig vaccination and treatment, sanitation and hygiene, and community education. Three potential drugs­niclosamide, praziquantel, and albendazole­have been considered for use for preventive chemotherapy in Taenia solium taeniasis control programs through mass drug administration or targeted chemotherapy. In this Guideline, we provide recommendations for preventive chemotherapy in Taenia solium-endemic areas using niclosamide, praziquantel, or albendazole, including at which dose and in which population groups. The development of this Guideline is based on the latest standard World Health Organization methods for guideline development, including the use of systematic search strategies, synthesis, quality assessment of the available evidence to support the recommendations, and participation of experts and stakeholders in the Guideline Development Group and External Review Group. The recommendations are intended for a wide audience, including policymakers and their expert advisers, and technical and program staff at governmental institutions and organizations involved in the planning, implementation, monitoring, and evaluation of preventive chemotherapy programs for the control of Taenia solium. Guideline for Preventive Chemotherapy for the Control of Taenia solium Taeniasis

A qualitative assessment of the context and enabling environment for the control of Taenia solium infections in endemic settings.

BACKGROUND: Taenia solium (T. solium), is a zoonotic helminth causing three diseases namely; taeniasis (in humans), neurocysticercosis (NCC, in humans) and porcine cysticercosis (PCC, in pigs) and is one of the major foodborne diseases by burden. The success or failure of control options against this parasite in terms of reduced prevalence or incidence of the diseases may be attributed to the contextual factors which underpin the design, implementation, and evaluation of control programmes. METHODOLOGY/PRINCIPAL FINDINGS: The study used a mixed method approach combining systematic literature review (SLR) and key informant interviews (KII). The SLR focused on studies which implemented T. solium control programmes and was used to identify the contextual factors and enabling environment relevant to successful inception, planning and implementation of the interventions. The SLR used a protocol pre-registered at the International prospective register of systematic reviews (PROSPERO) number CRD42019138107 and followed PRISMA guidelines on reporting of SLR. To further highlight the importance and interlinkage of these contextual factors, KII were conducted with researchers/implementers of the studies included in the SLR. The SLR identified 41 publications that had considerations of the contextual factors. They were grouped into efficacy (10), effectiveness (28) and scale up or implementation (3) research studies. The identified contextual factors included epidemiological, socioeconomic, cultural, geographical and environmental, service and organizational, historical and financial factors. The enabling environment was mainly defined by policy and strategies supporting T. solium control. CONCLUSION/SIGNIFICANCE: Failure to consider the contextual factors operating in target study sites was shown to later present challenges in project implementation and evaluation that negatively affected expected outcomes. This study highlights the importance of fully considering the various domains of the context and integrating these explicitly into the plan for implementation and evaluation of control programmes. Explicit reporting of these aspects in the resultant publication is also important to guide future work. The contextual factors highlighted in this study may be useful to guide future research and scale up of disease control programmes and demonstrates the importance of close multi-sectoral collaboration in a One Health approach.

Taenia solium taeniasis/cysticercosis: From parasite biology and immunology to diagnosis and control.

Infection with the pork tapeworm (Taenia solium) is responsible for a substantial global burden of disease, not only restricted to its impact on human health, but also resulting in a considerable economic burden to smallholder pig farmers due to pig cysticercosis infection. The life-cycle, parasitology and immunology of T. solium are complex, involving pigs (the intermediate host, harbouring the larval metacestode stage), humans (the definitive host, harbouring the adult tapeworm, in addition to acting as accidental intermediate hosts) and the environment (the source of infection with eggs/proglottids). We review the parasitology, immunology, and epidemiology of the infection associated with each of the T. solium life-cycle stages, including the pre-adult/adult tapeworm responsible for human taeniasis; post-oncosphere and cysticercus associated with porcine and human cysticercosis, and the biological characteristics of eggs in the environment. We discuss the burden associated, in endemic settings, with neurocysticercosis (NCC) in humans, and the broader cross-sectoral economic impact associated both with NCC and porcine cysticercosis, the latter impacting food-value chains. Existing tools for diagnostics and control interventions that target different stages of the T. solium transmission cycle are reviewed and their limitations discussed. Currently, no national T. solium control programmes have been established in endemic areas, with further work required to identify optimal strategies according to epidemiological setting. There is increasing evidence suggesting that cross-sectoral interventions which target the parasite in both the human and pig host provide the most effective approaches for achieving control and ultimately elimination. We discuss future avenues for research on T. solium to support the attainment of the goals proposed in the revised World Health Organisation neglected tropical diseases roadmap for 2021-2030 adopted at the 73rd World Health Assembly in November 2020.

Combined use of two separate but protective vaccine antigens provides protection against Taenia ovis infection in lambs in the presence of protective maternal antibody.

Three recombinant Taenia ovis antigens (To45, To16, To18) each induce protective immunity in lambs or ewes against infection with T. ovis metacestodes. The degree and duration of immunity were assessed in lambs born from vaccinated ewes. Treatment group sizes varied, typically not fewer than 5 animals per group. Ewes were immunised with one T. ovis recombinant protein prior to lambing and the degree and duration of passive immunity in their lambs was assessed by challenge infection up to 18 weeks. Lambs were fully protected up to 6 weeks of age but immunity waned from 6 to 12 weeks and there was no protection when lambs were challenged at 15 weeks. Immunisation of lambs with the homologous recombinant antigen was not effective when vaccinations were given when maternal antibody was high. Lambs were effectively immunised in the presence of passively protective antibody when vaccinated with an antigen that was different to that given to ewes. Vaccination of lambs with a combination of two proteins, To16 and To18, was more effective than giving these single antigens and gave a significant reduction of cyst numbers when lambs were challenged 12 months after immunisation. These results indicate that the use of combinations of T. ovis recombinant antigens could enable complete protection of lambs against infection, if a delivery system becomes available that will maintain antibody at protective levels for 12 months. Alternatively, a third injection given at 6 months may promote the anamnestic response to give long lasting protection.

Are current practices of yak herdsmen adequate to combat Coenurosis in Laya Bhutan?

BACKGROUND: Coenurosis, known commonly as gid, is caused by a tapeworm Taenia multiceps. It is a disease of small ruminants globally but also occurs in large ruminants, especially in yak in the Himalaya. Gid is a pathological condition in young yaks, mostly below 3 years of age. The infected animal displays a circling movement with the head tilting towards the location of the cyst of a tapeworm on the cerebral surface of the brain. OBJECTIVE: We conducted a study with the primary aim to gain an insight into yak herdsmen's practices to manage Coenurosis in the Laya administrative block of Bhutan. METHODS: All seven villages of Laya were included for sampling. Seventy-five out of 182 households owned yaks, and 54 yak-owning households were selected randomly. The government livestock officials of nine yak-rearing highland districts were also included in the study. A cross-sectional study was conducted based on a questionnaire survey and focussed mainly on herdsmen's practices to manage gid. Two sets of questionnaires were used for yak herders and livestock officials. Each predesigned questionnaire was semi-structured and consisted of both open- and closed-ended questions. RESULTS: The study revealed gid as a major cause of yak mortality. Gid occurred more in winter during migration and most herders lost one to three yaks annually. Herdsmen kept an average of two watchdogs and dewormed them once annually. Similarly, calves were also dewormed once annually. The carcasses of dead yaks were fed to dogs. Livestock officials were optimistic about controlling the disease in the future, despite the yak areas being difficult to access. Most herders had not attended the gid awareness programme. The animal health worker visited herds once annually. In absence of animal health workers, most herdsmen resorted to different practices to treat affected yaks -the most common practice being surgery. Gid was mentioned to harm herdsmen's economy. CONCLUSIONS: The study concluded that for effective management of gid in Laya, livestock agencies must create more awareness on gid, increase the frequency of visits by animal health workers to yak herds, and increase the frequency of deworming of watchdogs and calves.

[Current status and challenges for taeniasis and cysticercosis control in China].

In the WHO new road map for neglected tropical diseases 2021-2030, the disease-specific targets are classified into control, elimination as a public health problem, elimination and eradication, and taeniasis and cysticercosis are targeted for control. The overall prevalence of taeniasis and cysticercosis is low in China, and varies remarkably in regions and populations; however, there are many challenges for elimination of taeniasis and cysticercosis in China. Based on previous taeniasis and cysticercosis control programs, developing a sensitive taeniasis and cysticercosis surveillance-response system, updating criteria for diagnosis of taeniasis and cysticercosis, proposing a national guideline for treatment of taeniasis and cysticercosis, and strengthening interdisciplinary and intersectoral communications and collaborations are urgently needed under the One Health concept.

[Effectiveness of health education interventions targeting taeniasis and cysticercosis among primary school students in disease-elimination pilot areas of Henan Province].

OBJECTIVE: To compare the changes of knowledge, attitude and practice (KAP) related to taeniasis and cysticercosis among primary school students before and after health education interventions in disease-elimination pilot areas of Henan Province, so as to evaluate the effectiveness of health education interventions. METHODS: A primary school was selected from each of Dushu, Bowang and Yangji townships, Fangcheng County, Henan Province from 2017 to 2019; then, 2 to 3 classes were randomly selected from grade 4 to 6 in each primary school, and finally, all students in these classes were enrolled as study subjects. A thematic health education lecture pertaining to taeniasis and cysticercosis was given once each year by means of "health education in class". The KAP towards taeniasis and cysticercosis was investigated among primary school students using selffilled structured questionnaires, and the changes of awareness of taeniasis and cysticercosis control knowledge and percentage of healthy behaviors formation were compared in primary school students among years and following various frequencies of health education interventions. RESULTS: More than 10 thousand person-time primary school students received health education interventions during the period from 2017 to 2019, and a total of 1 223 person-time primary school students were investigated during the 3-year study period, including 633 person-time men and 590 person-time women and 88.55% of primary school students at ages of 10 to 12 years. The proportion of households raising pigs and using dry toiliets decreased from 5.30% (24/453) and 18.10% (82/453) in 2017 to 3.60% (13/361) and 11.08% (40/361) in 2019, respectively. The awareness rate of taeniasis and cysticercosis control knowledge increased significantly from 0.22% (1/453) in 2017 to 62.59% (256/409) in 2018 and 76.73% (277/361) in 2019 (χ2 = 567.60, P < 0.001), and the awareness rate was 85.25% (104/122) among primary school students attending the thematic special health education courses for successive three times. The awareness rates of taeniasis and cysticercosis control knowledge were 0.44% (1/225), 58.00% (116/200) and 71.63% (149/208) among male students and 0 (0/338), 66.99% (140/209) and 83.66% (128/153) among female students from 2017 to 2019, and there was a significant difference in the awareness of taeniasis and cysticercosis control knowledge between male and female students in 2019 (χ2 = 7.14, P = 0.01). On-site teaching by doctors was the students' favorite way to receive health education interventions (70.07%, 857/1 223), followed by watching health education videos (58.63%, 717/1 223) and seeing parasite specimens (48.9%, 598/1 223). The proportion of students' families who used cutting boards for raw and cooked food separately increased from 7.28% (33/453) in 2017 to 47.37% (171/361) in 2019, was 67.21% (82/122) among students attending the health education courses for successive three times. The proportion of students who frequently washed their hands before meals and after using toilet increased from 71.96% (324/453) in 2017 to 89.47% (319/361) in 2019 and was 95.90% (117/122) among students attending the health education courses for successive three times. In addition, the percentage of students washing hands frequently in families using dry toilets was significantly lower in those who did not use dry toilets (χ2 = 9.21, P = 0.002), and the proportion of students with a habit of eating raw or undercooked meat decreased significantly from 35.76% (162/453) in 2017 to 6.65% (24/361) in 2019 (χ2 = 69.11, P < 0.01). CONCLUSIONS: The thematic health education activity of "health education in class" contributes greatly to the increase in the awareness of taeniasis and cysticercosis control knowledge and the rate of healthy behaviors formation among primary school students in diseaseelimination pilot areas of Henan Province.

Bisphenol A induces protection through modulation of the immune response against the helminth parasite Taenia crassiceps.

AIMS: Industrial growth has increased the exposure to endocrine disruptor compounds (EDCs) in all organisms. Bisphenol A (BPA), an EDC, has been demonstrated to be involved in the susceptibility to parasite infections. However, few studies have analysed this connection in more depth. The aim of this study was to determine whether early BPA exposure in female mice affects the systemic immune response and the susceptibility to Taenia crassiceps infection. METHODS AND RESULTS: BALB/c mice were exposed to BPA at post-natal day 3. At 6 weeks of age, they were inoculated with T crassiceps larvae and, 2 weeks later, were euthanized. The number of parasites was quantified. By flow cytometry, in the spleen, the peripheral and mesenteric lymph nodes, the different innate and adaptive immune cell modulation was analysed, and RT-PCR cytokine expression was also evaluated. BPA induced a reduction of 40% in parasite load. BPA treatment modulated some lineages of the innate immune response and caused slight changes in cells belonging to the adaptive immune response. Additionally, BPA enhanced the type 2 cytokine profile. CONCLUSION: Neonatal BPA treatment in female mice affects not only the percentage of different immune cells but also their ex vivo cytokine gene expression, decreasing T crassiceps cysticercosis susceptibility.