Effectiveness of a community-based educational programme in reducing the cumulative incidence and prevalence of human Taenia solium cysticercosis in Burkina Faso in 2011-14 (EFECAB): a cluster-randomised controlled trial

We outside: Modeling equity-centered, antiracist, community-driven partnerships in resident education

Background

Community engagement is increasingly recognized as a necessity in addressing intractable racial and ethnic health disparities in the United States. However, institutions have not adequately trained resident physicians in developing symbiotic community partnerships that preserve community autonomy and identity without exploitation. Our goals were to highlight the experiences of expert academic emergency physicians in creating innovative, community-driven, and anti-racist solutions to achieving measurable equity in health outcomes and to introduce a novel framework entitled the Social Change Method to take a community-embedded intervention from concept to creation.

Methods

The methodology was based on the development of a didactic session at the 2023 SAEM Annual Meeting. The three novel initiatives discussed were Emergency Medicine Remix (EMR); Trust, Research, Access, and Prevention (TRAP) Medicine; and The Health Equity Accelerator (HEA). A team of multi-institutional experts convened to develop the session objectives through priority setting.

Results

Our expert panel discussed successes and challenges encountered while using evidence-informed strategies to conduct their community-based programming. Participant questions were centered on fostering sustainability, emphasizing the importance of carefully crafted interventions in the face of uncertain legislative challenges and strategies to empower others.

Conclusions

Emergency medicine residency education should incorporate training on methods to leverage community partnerships to improve individual and community health outcomes. The Social Change Method can be used as a conceptual framework to generate easily re-creatable and scalable partnerships that establish trust and forge relationships that honor identity and autonomy without exploiting community members.

The Vicious Worm education tool improves the knowledge of community health workers on Taenia solium cysticercosis in Rwanda

The pork tapeworm Taenia solium causes human taeniasis and cysticercosis when ingested as viable cysts and eggs, respectively. Despite its high health burden in low-income countries, knowledge of the parasite in endemic areas such as Rwanda is often limited. Here, we assess whether The Vicious Worm education software can increase knowledge in endemic areas of Rwanda. A cross-sectional mixed-methods study was conducted to evaluate knowledge about T. solium among community health workers trained using the Vicious Worm education software. Knowledge was assessed before, immediately after, and four weeks after the training. The health workers perceptions of the software were analysed thematically. A total of 207 community health workers were recruited from Nyamagabe district in Southern Province, Rwanda. Participants were composed of males (33.5%) and females (66.5%), aged between 22 and 68 years, and most (71%) had only completed primary education. Knowledge of cysticercosis at baseline was low, particularly knowledge of human cysticercosis and neurocysticercosis. The overall knowledge score increased significantly after training and was maintained four weeks after the training. Overall, insufficient knowledge was associated with neurocysticercosis-related questions, which after the training, remained relatively lower compared to questions of other categories. Participants reported the software to be user-friendly and educational. Digital illiteracy and the lack of smartphones were among the critical challenges highlighted in responses. This study has shown gaps in knowledge regarding T. solium infections within rural Rwanda, particularly neurocysticercosis. Health education using the Vicious Worm education software should be considered in integrated control programs.

Aggregation of Taenia solium cysticerci in pigs: Implications for transmission and control

Parasite aggregation within hosts is a fundamental feature of parasite distributions, whereby the majority of parasites are harboured by a minority of hosts. Parasite aggregation can influence their transmission and hence control. In this narrative review, possible sources of aggregation of Taenia solium cysticerci in pigs are discussed, along with implications for control of the parasite. While heavy T. solium infections in pigs could most likely be associated with ingestion of high doses of infective parasite eggs, consistent with coprophagic behaviour of pigs, lighter infections indicate a role of indirect routes of transmission to pigs, mostly from lower infection doses. Light infections are likely to be missed by commonly used diagnostic methods - tongue examination or meat inspection - and end up in the food chain. Hence, they entail a 'hidden' risk and are of a particular public health concern, especially in areas where meat is consumed raw or undercooked. To be effective and sustainable, control strategies against T. solium likely require a broader understanding of, and consideration for parasite transmission dynamics. More importantly, a holistic One Health approach incorporating interventions on humans, pigs and the environment will likely have a larger, more successful and sustainable impact.

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.

Geostatistical analysis of active human cysticercosis: Results of a large-scale study in 60 villages in Burkina Faso

Cysticercosis is a neglected tropical disease caused by the larval stage of the zoonotic tapeworm (Taenia solium). While there is a clear spatial component in the occurrence of the parasite, no geostatistical analysis of active human cysticercosis has been conducted yet, nor has such an analysis been conducted for Sub-Saharan Africa, albeit relevant for guiding prevention and control strategies. The goal of this study was to conduct a geostatistical analysis of active human cysticercosis, using data from the baseline cross-sectional component of a large-scale study in 60 villages in Burkina Faso. The outcome was the prevalence of active human cysticercosis (hCC), determined using the B158/B60 Ag-ELISA, while various environmental variables linked with the transmission and spread of the disease were explored as potential explanatory variables for the spatial distribution of T. solium. A generalized linear geostatistical model (GLGM) was run, and prediction maps were generated. Analyses were conducted using data generated at two levels: individual participant data and grouped village data. The best model was selected using a backward variable selection procedure and models were compared using likelihood ratio testing. The best individual-level GLGM included precipitation (increasing values were associated with an increased odds of positive test result), distance to the nearest river (decreased odds) and night land temperature (decreased odds) as predictors for active hCC, whereas the village-level GLGM only retained precipitation and distance to the nearest river. The range of spatial correlation was estimated at 45.0 [95%CI: 34.3; 57.8] meters and 28.2 [95%CI: 14.0; 56.2] km for the individual- and village-level datasets, respectively. Individual- and village-level GLGM unravelled large areas with active hCC predicted prevalence estimates of at least 4% in the south-east, the extreme south, and north-west of the study area, while patches of prevalence estimates below 2% were seen in the north and west. More research designed to analyse the spatial characteristics of hCC is needed with sampling strategies ensuring appropriate characterisation of spatial variability, and incorporating the uncertainty linked to the measurement of outcome and environmental variables in the geostatistical analysis. Trial registration: ClinicalTrials.gov; NCT0309339.

Innovative Research Offers New Hope for Managing African Swine Fever Better in Resource-Limited Smallholder Farming Settings: A Timely Update

African swine fever (ASF) in domestic pigs has, since its discovery in Africa more than a century ago, been associated with subsistence pig keeping with low levels of biosecurity. Likewise, smallholder and backyard pig farming in resource-limited settings have been notably affected during the ongoing epidemic in Eastern Europe, Asia, the Pacific, and Caribbean regions. Many challenges to managing ASF in such settings have been identified in the ongoing as well as previous epidemics. Consistent implementation of biosecurity at all nodes in the value chain remains most important for controlling and preventing ASF. Recent research from Asia, Africa, and Europe has provided science-based information that can be of value in overcoming some of the hurdles faced for implementing biosecurity in resource-limited contexts. In this narrative review we examine a selection of these studies elucidating innovative solutions such as shorter boiling times for inactivating ASF virus in swill, participatory planning of interventions for risk mitigation for ASF, better understanding of smallholder pig-keeper perceptions and constraints, modified culling, and safe alternatives for disposal of carcasses of pigs that have died of ASF. The aim of the review is to increase acceptance and implementation of science-based approaches that increase the feasibility of managing, and the possibility to prevent, ASF in resource-limited settings. This could contribute to protecting hundreds of thousands of livelihoods that depend upon pigs and enable small-scale pig production to reach its full potential for poverty alleviation and food security.

Foodborne zoonoses control in low- and middle-income countries: Identifying aspects of interventions relevant to traditional markets which act as hurdles when mitigating disease transmission

Globally, foodborne zoonoses are responsible for approximately one third of all foodborne disease burden and this picture is likely to worsen if consumption of animal source foods continues to rise with insufficient attention to risk mitigation. Traditional markets represent highly important nodes that can be targeted for risk mitigation; in this series of case studies, we discuss food safety interventions relevant to this nexus. We illustrate that to improve food safety within traditional markets it is essential to consider some of the motivations and incentives of the stakeholders involved and the cultural, social, and economic context in which interventions are undertaken, highlighting barriers, enablers future interventions should aim to avoid, embrace. We also conclude that a holistic approach to foodborne zoonoses control will require the institutionalization of One Health across food systems of which traditional markets are part.

Neurocysticercosis control for primary epilepsy prevention: a systematic review

Neurocysticercosis (NCC) is a leading cause of preventable epilepsy in lower- and upper- middle-income countries (LMICs/UMICs). NCC is a human-to-human transmitted disease caused by ingestion of Taenia solium eggs from a Taenia carrier. T. solium infection control is the key to reduce NCC incidence. This systematic review aims to identify T. solium control programs that can provide frameworks for endemic areas to prevent NCC-related epilepsy. A systematic search was conducted in PubMed/Medline, Embase, Web of Science, and Cochrane Library databases in March 2021. After title and abstract review, full texts were screened for qualitative analysis. Additional articles were identified via citation search. Of 1322 total results, 34 unique studies were included. Six major intervention types were identified: national policy (8.8%), community sanitation improvement (8.8%), health education (8.8%), mass drug administration (29.4%), pig vaccination and treatment (32.4%), and combined human and pig treatment (11.8%). Overall, 28 (82.4%) studies reported decreased cysticercosis prevalence following the intervention. Only health education and combined human and pig treatment were effective in all selected studies. NCC causes preventable epilepsy in LMICs/UMICs and its incidence can be reduced through T. solium control. Most interventions that disrupt the T. solium transmission cycle are effective. Long-term sustained results require comprehensive programs, ongoing surveillance, and collaborative effort among multisectoral agencies.

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.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07408-0.

Maximising Societal Benefit From the Control of Neglected Zoonoses: Identifying Synergies and Trade-Offs in the Control of Taenia solium

Interventions to control or eradicate neglected zoonoses are generally paid for through the public purse and when these interventions focus on the animal hosts, they are often expected to be performed and financed through the state veterinary service. The benefits of control, however, accrue across the human, animal, and environmental spaces and enhance both public and private interests. Additionally, disease control interventions do not take place in a vacuum and the indirect impacts of our actions should also be considered if the societal benefit of interventions is to be maximised. With the caveat that unintended consequences can and will occur, pre-identifying potential synergies and trade-offs in our disease control initiatives allows for them to be considered in intervention design and monitored during programme roll-out. In this paper, using a One Health approach with the example of Taenia solium control, we identify potential indirect impacts which may arise and how these may influence both our choice of intervention and opportunities to optimise the animal, environmental, and societal benefits of control through maximising synergies and minimising trade-offs.

The Interplay Between Neuroinfections, the Immune System and Neurological Disorders: A Focus on Africa

Neurological disorders related to neuroinfections are highly prevalent in Sub-Saharan Africa (SSA), constituting a major cause of disability and economic burden for patients and society. These include epilepsy, dementia, motor neuron diseases, headache disorders, sleep disorders, and peripheral neuropathy. The highest prevalence of human immunodeficiency virus (HIV) is in SSA. Consequently, there is a high prevalence of neurological disorders associated with HIV infection such as HIV-associated neurocognitive disorders, motor disorders, chronic headaches, and peripheral neuropathy in the region. The pathogenesis of these neurological disorders involves the direct role of the virus, some antiretroviral treatments, and the dysregulated immune system. Furthermore, the high prevalence of epilepsy in SSA (mainly due to perinatal causes) is exacerbated by infections such as toxoplasmosis, neurocysticercosis, onchocerciasis, malaria, bacterial meningitis, tuberculosis, and the immune reactions they elicit. Sleep disorders are another common problem in the region and have been associated with infectious diseases such as human African trypanosomiasis and HIV and involve the activation of the immune system. While most headache disorders are due to benign primary headaches, some secondary headaches are caused by infections (meningitis, encephalitis, brain abscess). HIV and neurosyphilis, both common in SSA, can trigger long-standing immune activation in the central nervous system (CNS) potentially resulting in dementia. Despite the progress achieved in preventing diseases from the poliovirus and retroviruses, these microbes may cause motor neuron diseases in SSA. The immune mechanisms involved in these neurological disorders include increased cytokine levels, immune cells infiltration into the CNS, and autoantibodies. This review focuses on the major neurological disorders relevant to Africa and neuroinfections highly prevalent in SSA, describes the interplay between neuroinfections, immune system, neuroinflammation, and neurological disorders, and how understanding this can be exploited for the development of novel diagnostics and therapeutics for improved patient care.

Spatial distribution and risk factors for human cysticercosis in Colombia

Background

Cysticercosis is a zoonotic neglected tropical disease (NTD) that affects humans and pigs following the ingestion of Taenia solium eggs. Human cysticercosis poses a substantial public health burden in endemic countries. The World Health Organization (WHO) aims to target high-endemicity settings with enhanced interventions in 17 countries by 2030. Between 2008 and 2010, Colombia undertook a national baseline serosurvey of unprecedented scale, which led to an estimated seroprevalence of T. solium cysticercus antibodies among the general population of 8.6%. Here, we use contemporary geostatistical approaches to analyse this unique dataset with the aim of understanding the spatial distribution and risk factors associated with human cysticercosis in Colombia to inform how best to target intervention strategies.

Methods

We used a geostatistical model to estimate individual and household risk factors associated with seropositivity to T. solium cysticercus antibodies from 29,253 people from 133 municipalities in Colombia. We used both independent and spatially structured random effects at neighbourhood/village and municipality levels to account for potential clustering of exposure to T. solium. We present estimates of the distribution and residual correlation of seropositivity at the municipality level.

Results

High seroprevalence was identified in municipalities located in the north and south of Colombia, with spatial correlation in seropositivity estimated up to approximately 140 km. Statistically significant risk factors associated with seropositivity to T. solium cysticercus were related to age, sex, educational level, socioeconomic status, use of rainwater, consumption of partially cooked/raw pork meat and possession of dogs.

Conclusions

In Colombia, the distribution of human cysticercosis is influenced by socioeconomic considerations, education and environmental factors related to the spread of T. solium eggs. This information can be used to tailor national intervention strategies, such as targeting spatial hotspots and more highly exposed groups, including displaced people and women. Large-scale seroprevalence surveys accompanied by geospatial mapping are an essential step towards reaching the WHO’s 2021‒2030 NTD roadmap targets.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-05092-8.

Geographically Targeted Interventions versus Mass Drug Administration to Control Taenia solium Cysticercosis, Peru

Optimal control strategies for Taenia solium taeniasis and cysticercosis have not been determined. We conducted a 2-year cluster randomized trial in Peru by assigning 23 villages to 1 of 3 geographically targeted intervention approaches. For ring screening (RS), participants living near pigs with cysticercosis were screened for taeniasis; identified cases were treated with niclosamide. In ring treatment (RT), participants living near pigs with cysticercosis received presumptive treatment with niclosamide. In mass treatment (MT), participants received niclosamide treatment every 6 months regardless of location. In each approach, half the villages received targeted or mass oxfendazole for pigs (6 total study arms). We noted significant reductions in seroincidence among pigs in all approaches (67.1% decrease in RS, 69.3% in RT, 64.7% in MT; p<0.001), despite a smaller proportion of population treated by targeted approaches (RS 1.4%, RT 19.3%, MT 88.5%). Our findings suggest multiple approaches can achieve rapid control of T. solium transmission.

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.

Data-driven analyses of behavioral strategies to eliminate cysticercosis in sub-Saharan Africa

Background

The multi-host taeniosis/cysticercosis disease system is associated with significant neurological morbidity, as well as economic burden, globally. We investigated whether lower cost behavioral interventions are sufficient for local elimination of human cysticercosis in Boulkiemdé, Sanguié, and Nayala provinces of Burkina Faso.

Methodology/Principal findings

Province-specific data on human behaviors (i.e., latrine use and pork consumption) and serological prevalence of human and pig disease were used to inform a deterministic, compartmental model of the taeniosis/cysticercosis disease system. Parameters estimated via Bayesian melding provided posterior distributions for comparing transmission rates associated with human ingestion of Taenia solium cysticerci due to undercooking and human exposure to T. solium eggs in the environment. Reductions in transmission via these pathways were modeled to determine required effectiveness of a market-focused cooking behavior intervention and a community-led sanitation and hygiene program, independently and in combination, for eliminating human cysticercosis as a public health problem (<1 case per 1000 population). Transmission of cysticerci due to consumption of undercooked pork was found to vary significantly across transmission settings. In Sanguié, the rate of transmission due to undercooking was 6% higher than that in Boulkiemdé (95% CI: 1.03, 1.09; p-value < 0.001) and 35% lower than that in Nayala (95% CI: 0.64, 0.66; p-value < 0.001). We found that 67% and 62% reductions in undercooking of pork consumed in markets were associated with elimination of cysticercosis in Nayala and Sanguié, respectively. Elimination of active cysticercosis in Boulkiemdé required a 73% reduction. Less aggressive reductions of 25% to 30% in human exposure to Taenia solium eggs through sanitation and hygiene programs were associated with elimination in the provinces.

Conclusions/Significance

Despite heterogeneity in effectiveness due to local transmission dynamics and behaviors, education on the importance of proper cooking, in combination with community-led sanitation and hygiene efforts, has implications for reducing morbidity due to cysticercosis and neurocysticercosis.

It is important to consider context-specific behaviors and transmission pathways when designing scalable and sustainable intervention strategies for neglected tropical diseases (NTDs). To reduce the morbidity and mortality associated with cysticercosis, suites of interventions have been recommended but are inconsistently implemented due to cost and feasibility-related constraints. This study investigated the potential of a cooking intervention to interrupt transmission via undercooked pork in marketplaces of Burkina Faso. The sensitivity of Taenia solium parasite to temperatures attainable via improved cooking strategies provides a low-cost, human-centered approach to prevent consumption of infected pork meals. By accounting for differential behavior and the relative role of this transmission route across three provinces, we show how the potential of cysticercosis elimination (as a public health problem) varies across behavior-focused interventions. Further investigation into intervention strategies against human and pig cysticercosis warrants data-driven analyses that account for local variation in transmission behaviors.

Zoonotic Taenia infections with focus on cysticercosis due to Taenia solium in swine and humans

Zoonotic taeniasis caused by the adult stage of Taenia solium, Taenia saginata or Taenia asiatica are considered neglected tropical diseases by the World Health Organization. The life cycle of these 3 metazoan species is very similar and includes an intermediate host: pigs in the case of T. solium and T. asiatica, and cattle in the case of T. saginata. By eating meat (pork/T. solium, T. asiatica; beef/T. saginata) containing live cysticerci, humans develop taeniasis, which is practically asymptomatic but is the main risk factor for intermediate hosts to become infected. T. saginata causes bovine cysticercosis, while T. solium and T. asiatica cause swine cysticercosis, of veterinary and economic importance. T. solium cysticerci cause neurological disease in humans: neurocysticercosis. Cysticerci develop after ingesting microscopic eggs released from a human tapeworm carrier. Here we describe the life stages of the parasites, diagnosis, pathogenesis, symptomatology of neurocysticercosis, and prevention and control measures. Highlighting the need to validate diagnostic tools, treatments and vaccination in endemic areas, with the challenge of addressing the most vulnerable populations that lack resources. If people understand the transmission route, avoid eating uncooked or insufficiently cooked meat and have adequate hygienic habits, the life cycle of the 3 zoonotic Taenia species may be interrupted. In addition, we describe the growing field of immune response and immunomodulation elicited by the parasites, which may provide essential tools for diagnosis, treatment, control of taeniasis/cysticercosis, as well as for identification of parasite-derived immunomodulators that could aid in the treatment of emerging inflammatory diseases worldwide.

Effects of 'The Vicious Worm' educational software on Taenia solium knowledge among key pork supply chain workers in Zambia

The neglected zoonotic cestode Taenia solium is endemic in many low- and middle-income countries, including Zambia. The parasite infects humans and pigs, inflicting high socioeconomic and disease burdens in endemic areas. Health education is regarded as an important component in T. solium control and previous studies indicate that ‘The Vicious Worm’ may be an effective T. solium health education tool for Tanzanian medical and agricultural professionals and Zambian primary school students. This study aimed to assess the effects of health education using ‘The Vicious Worm’ among Zambian pork supply chain workers, because the pork supply chain greatly influences food safety and security in Zambia. Half-day educational workshops using ‘The Vicious Worm’ and subsequent follow-up sessions were organized in the Lusaka and Katete districts of Zambia in March and April 2019. Questionnaires were administered before, after, and three weeks after the use of ‘The Vicious Worm’ to assess the program’s impact on knowledge uptake and short-term retention. Focus group discussions were conducted to assess the program’s user experience and the participants’ beliefs, attitudes, and insights. In total, 47 pork supply chain workers participated: 25 from Lusaka and 22 from Katete. Overall, knowledge about T. solium was significantly higher (p<0.001) both immediately after, and three weeks after the use of ‘The Vicious Worm’ compared to baseline knowledge. Focus group discussions indicated incipient attitudinal and behavioral change, as well as a positive reception of the software; with participants describing the software as simple, educative, and useful to share knowledge. The study results indicate that workshops using ‘The Vicious Worm’ may be effective for short-term T. solium health education among key pork supply chain workers. Follow-up studies are required to assess long-term effects, transfer of knowledge and behavioral change. However, educational interventions with ‘The Vicious Worm’ could be considered for integrated T. solium control programs in sub-Saharan Africa, especially if the educational content is further simplified and clarified.

The tapeworm Taenia solium causes epilepsy and severe headaches in humans and economic losses to smallholder farmers in endemic areas where free-roaming pigs, poor sanitation and informal animal slaughter are prevalent. Treatment of human taeniosis and interventions in pigs (vaccination and anthelmintic treatment) have been established as essential tools to achieve short-term control, but health education will be crucial to sustain long-term control. ‘The Vicious Worm’ is a specific T. solium health education tool aiming to convey simple and meaningful messages concerning disease prevention and control. Previous studies found significant knowledge increases after the use of the educational tool in Tanzanian medical and agricultural professionals, and Zambian primary school students. We organized half-day educational workshops using ‘The Vicious Worm’ for pork supply chain workers at two study sites in Zambia, with follow-up visits three weeks later. We found a significant increase in participants’ knowledge, both immediately and three weeks after the health education. Furthermore, the program was well received and potentially led to attitudinal and behavioral change that could deter the propagation of T. solium. We conclude that ‘The Vicious Worm’ educational interventions may contribute to a safer pork supply chain and we encourage its implementation in future T. solium control strategies.

Perceptions and acceptability of piloted Taenia solium control and elimination interventions in two endemic communities in eastern Zambia

Infections with Taenia solium cause significant public health and economic losses worldwide. Despite effective control tools, long-term sustained control/elimination of the parasite has not been demonstrated to date. Success of intervention programs is dependent on their acceptability to local communities. Focus group discussions (FGDs) and questionnaires (QS) were conducted in two study communities in eastern Zambia to assess local perceptions and acceptance of two piloted intervention strategies: one targeting pigs only ('control' study arm), and one integrated human- and pig-based ('elimination') strategy. QS (n = 227) captured data regarding participation in project activities, knowledge and perceptions of T. solium and of the interventional drugs used in the study. FGDs (n = 18) discussed perceived advantages and disadvantages of the interventions and of the project's delivery and value. QS data revealed 67% of respondents participated in at least one educational activity, and 80% correctly identified at least one disease targeted by the education. All elimination study arm respondents (n = 113) had taken the human treatment, and 98% intended to do so next time. Most (70%) indicated willingness to pay for future treatments (median 0.20 USD per dose). Of pig-owning respondents, 11/12 (92%) had allowed their pigs to be treated/vaccinated and all intended to do so again next time. Four pig owners indicated willingness to pay 0.10-0.50 USD per dose of treatment or vaccine. FGD feedback revealed positive perceptions of interventions; people reported improved health in themselves and their pigs, and fewer cysticerci in pork. Latrine use, hand washing, meat inspection and proper cooking of pork had reportedly increased since the program's inception. Preliminary assessment indicates that the piloted intervention methods are generally acceptable to the communities. The reported willingness of many respondents to pay for the medications would contribute to the feasibility of long-term, government-led T. solium intervention programs in future.

Taenia solium Cysticercosis and Its Impact in Neurological Disease

Taenia solium neurocysticercosis (NCC) is endemic in most of the world and contributes significantly to the burden of epilepsy and other neurological morbidity. Also present in developed countries because of immigration and travel, NCC is one of few diseases targeted for eradication. This paper reviews all aspects of its life cycle (taeniasis, porcine cysticercosis, human cysticercosis), with a focus on recent advances in its diagnosis, management, and control. Diagnosis of taeniasis is limited by poor availability of immunological or molecular assays. Diagnosis of NCC rests on neuroimaging findings, supported by serological assays. The treatment of NCC should be approached in the context of the particular type of infection (intra- or extraparenchymal; number, location, and stage of lesions) and has evolved toward combined symptomatic and antiparasitic management, with particular attention to modulating inflammation. Research on NCC and particularly the use of recently available genome data and animal models of infection should help to elucidate mechanisms of brain inflammation, damage, and epileptogenesis.

Reinventing the Wheel of Echinococcus granulosus sensu lato Transmission to Humans

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

To Really Know the Disease: Creating a Participatory Community Education Workshop about Taenia solium Focused on Physical, Economic, and Epidemiologic Evidence

Cysticercosis, caused by Taenia solium, is a neglected disease that causes preventable epilepsy. We conducted an experiential learning workshop in northern Peru to educate community members on T. solium transmission and motivate participation in community-led prevention and control. The workshop included presentation of local economic and epidemiologic data, followed by hands-on participation in pig dissection, group discussion of the T. solium life cycle, and viewing of eggs and nascent tapeworms with light microscopes. Among heads of household, we used community survey data to compare knowledge of the three-stage parasite life cycle at baseline and 2 months postworkshop. Knowledge of the life cycle increased significantly after the workshop, with greater gains for workshop attendees than non-attendees. Prior knowledge and workshop attendance were significant predictors of postworkshop knowledge. The use of local evidence and experiential learning positively affected knowledge of T. solium transmission, laying the foundation for subsequent community-engaged control efforts.

The World Health Organization 2030 goals for Taenia solium: Insights and perspectives from transmission dynamics modelling: CystiTeam Group for Epidemiology and Modelling of Taenia solium Taeniasis/Cysticercosis

Taenia solium (TS), responsible for porcine cysticercosis, human taeniasis and (neuro)cysticercosis, was included in the World Health Organization neglected tropical disease (NTD) roadmap published in 2012. Targets set in this roadmap have not been met, but T. solium has been included in the consultation process for the new 2030 goals proposed for priority NTDs. Taenia solium transmission dynamics models can contribute to this process. A recent review has compared existing T. solium transmission models, identifying their similarities and differences in structure, parameterization and modelled intervention approaches. While a formal model comparison to investigate the impact of interventions is yet to be conducted, the models agree on the importance of coverage for intervention effectiveness and on the fact that human- and pig-focused interventions can be optimally combined. One of these models, cystiSim, an individual-based, stochastic model has been used to assess field-applicable interventions, some currently under evaluation in on-going trials in Zambia. The EPICYST, population-based, deterministic model has highlighted, based on simulating a generic sub-Saharan Africa setting, the higher efficacy (measured as the percentage of human cysticercosis cases prevented) of biomedical interventions (human and pig treatment and pig vaccination) compared to improved husbandry, sanitation, and meat inspection. Important questions remain regarding which strategies and combinations thereof provide sustainable solutions for severely resource-constrained endemic settings. Defining realistic timeframes to achieve feasible targets, and establishing suitable measures of effectiveness for these targets that can be quantified with current monitoring and evaluation tools, are current major barriers to identifying validated strategies. Taenia solium transmission models can support setting achievable 2030 goals; however, the refinement of these models is first required. Incorporating socio-economic elements, improved understanding of underlying biological processes, and consideration of spatial dynamics are key knowledge gaps that need addressing to support model development.

The World Health Organization 2030 goals for Taenia solium: Insights and perspectives from transmission dynamics modelling: CystiTeam Group for Epidemiology and Modelling of Taenia solium Taeniasis/Cysticercosis

Taenia solium (TS), responsible for porcine cysticercosis, human taeniasis and (neuro)cysticercosis, was included in the World Health Organization neglected tropical disease (NTD) roadmap published in 2012. Targets set in this roadmap have not been met, but T. solium has been included in the consultation process for the new 2030 goals proposed for priority NTDs. Taenia solium transmission dynamics models can contribute to this process. A recent review has compared existing T. solium transmission models, identifying their similarities and differences in structure, parameterization and modelled intervention approaches. While a formal model comparison to investigate the impact of interventions is yet to be conducted, the models agree on the importance of coverage for intervention effectiveness and on the fact that human- and pig-focused interventions can be optimally combined. One of these models, cystiSim, an individual-based, stochastic model has been used to assess field-applicable interventions, some currently under evaluation in on-going trials in Zambia. The EPICYST, population-based, deterministic model has highlighted, based on simulating a generic sub-Saharan Africa setting, the higher efficacy (measured as the percentage of human cysticercosis cases prevented) of biomedical interventions (human and pig treatment and pig vaccination) compared to improved husbandry, sanitation, and meat inspection. Important questions remain regarding which strategies and combinations thereof provide sustainable solutions for severely resource-constrained endemic settings. Defining realistic timeframes to achieve feasible targets, and establishing suitable measures of effectiveness for these targets that can be quantified with current monitoring and evaluation tools, are current major barriers to identifying validated strategies. Taenia solium transmission models can support setting achievable 2030 goals; however, the refinement of these models is first required. Incorporating socio-economic elements, improved understanding of underlying biological processes, and consideration of spatial dynamics are key knowledge gaps that need addressing to support model development.

Factors Associated with the 18-Month Cumulative Incidence of Seroconversion of Active Infection with Taenia solium Cysticercosis: A Cohort Study among Residents of 60 Villages in Burkina Faso

Taeniasis/cysticercosis (CC) is an important disease complex with significant burden. This large-scale cohort study aimed at estimating and exploring individual- and village-level factors associated with the cumulative incidences of seroconversion (SC) and seroreversion (SR) of active human CC in three provinces of Burkina Faso. In 60 villages, blood samples were collected and interviews regarding sociodemographic variables and knowledge, attitude, and practices toward the disease complex were conducted at baseline and 18-month follow-up (N = 2,211), with the presence of active CC being determined using the B158/B60 antigen enzyme-linked immunosorbent assay (Ag-ELISA). The 18-month Ag SC and SR were estimated at 3.3% (95% confidence interval [CI]: 2.6; 4.2%) and 35.8% (95% CI: 24.5; 48.5%), respectively. Marked provincial differences were found for the 18-month Ag SC (Boulkiemde: cumulative incidence ratio [CIR]: 2.41 (95% CI: 1.21; 4.78) and Nayala: CIR: 3.28 (95% CI: 1.37; 7.84), compared with Sanguie), while not being significantly associated with other sociodemographic factors. A continued refraining from pork consumption was associated with a lower 18-month Ag SC (CIR: 0.55 [95% CI: 0.28; 1.07]), whereas at the village level, the percentage of households owning pigs was associated with a higher 18-month Ag SC (CIR: 1.03 [95% CI: 1.01; 1.05]). In conclusion, this is one of few cohort studies and the first to have enough power to assess possible causal links between individual- and village-level variables and CC in humans. Variables linked to province, pig raising, and pork consumption behaviors were found to cause Ag SC in humans. The latter results further support the importance of adopting a One Health approach to the control of CC.

Control of Taenia solium; A Case for Public and Private Sector Investment

The zoonotic helminth T. solium is one of the leading causes of acquired epilepsy in endemic countries, resulting in a high burden both in human health and social stigma of affected people (1-3). In 2012 T. solium was highlighted as a priority for control in the World Health Assembly resolution 66.12 (4). Despite a call for validated control strategies by 2015 and a "Tool Kit" of control options being available, relatively few examples of successfully implemented and sustainable control programs are available (5-7). A minimal control strategy focusing solely on the porcine host has also been proposed although the cost-effectiveness of such has yet to be explored (8). Although acknowledgment has been made of the need for initiatives to be sustainable, we are yet to see sufficient consideration of the balance between the provision of public and private goods, and the need for engagement of the people and organizations in the pork value chains within T. solium control strategies. We utilized a food chain risk analysis model to determine the incremental cost-effectiveness ratio (ICER) in terms of $/infective meal avoided, of combining a pharmaceutical intervention in pigs with strengthened meat hygiene services. The addition of a vaccination and treatment protocol, at an additional 10.3% cost, was illustrated to have the potential to improve the ICER of improving meat inspection by 74.6%. The vaccination and treatment protocol also had the potential to reduce the losses borne by the pork industry of condemned meat by 66%, highlighting the potential to leverage private sector investment in T. solium control.

Effects of 'The Vicious Worm' educational tool on Taenia solium knowledge retention in Zambian primary school students after one year

BACKGROUND

Taenia solium is a neglected zoonotic parasite endemic throughout many low-income countries worldwide, including Zambia, where it causes human and pig diseases with high health and socioeconomic burdens. Lack of knowledge is a recognized risk factor, and consequently targeted health educational programs can decrease parasite transmission and disease occurrence in endemic areas. Preliminary assessment of the computer-based education program 'The Vicious Worm' in rural areas of eastern Zambia indicated that it was effective at increasing knowledge of T. solium in primary school students. The aim of this study was to evaluate the impact of 'The Vicious Worm' on knowledge retention by re-assessing the same primary school students one year after the initial education workshops.

METHODOLOGY/PRINCIPAL FINDINGS

Follow-up questionnaires were administered in the original three primary schools in eastern Zambia in 2017, 12 months after the original workshops. In total, 86 pupils participated in the follow-up sessions, representing 87% of the initial workshop respondents. Knowledge of T. solium at 'follow-up' was significantly higher than at the initial 'pre' questionnaire administered during the Vicious Worm workshop that took place one year earlier. While some specifics of the parasite's life cycle were not completely understood, the key messages for disease prevention, such as the importance of hand washing and properly cooking pork, remained well understood by the students, even one year later.

CONCLUSIONS/SIGNIFICANCE

Results of this study indicate that 'The Vicious Worm' may be an effective tool for both short- and long-term T. solium education of rural primary school students in Zambia. Inclusion of educational workshops using 'The Vicious Worm' could be recommended for integrated cysticercosis control/elimination programs in sub-Saharan Africa, particularly if the content is simplified to focus on the key messages for prevention of disease transmission.

Taenia solium control in Zambia: The potholed road to success

The taeniosis/cysticercosis neglected zoonotic disease complex is caused by Taenia solium, and is associated with significant economic and public health impacts. This paper reviews the current knowledge on T. solium in Zambia and the control strategies already studied, covering almost 20 years of research, and explores the way forward. Studies on occurrence of porcine cysticercosis indicated very high prevalences, ranging from 15 to 34% based on detection of circulating antigens, and of 46% to 68% based on full carcass dissection in slaughter age pigs. Taeniosis prevalences have been reported to range from 6.3% to 12% based on copro-Ag-ELISA. Human cysticercosis prevalence results ranged from 5.8% to 13% based on serum Ag-ELISA, and from 34% to 39% based on sero-antibody detection. Later on, a study in people with epilepsy suggested neurocysticercosis to be the single most important cause of epilepsy in this T. solium endemic area, with 57% of the people with active epilepsy diagnosed with probable or definite neurocysticercosis. While the need to reduce the disease burden of T. solium in Zambia is obvious, the exact short and long term goals, and the strategies to achieve these goals, are not clear. We have selected the most promising control/elimination strategies from reviews and assessed these for feasibility via discussions with local stakeholders from both medical and veterinary sectors. The proposed measures were evaluated using the newly developed agent-based disease transmission model, cystiSim and optimised using Zambian demographic and disease data. As a control option, yearly porcine treatments were selected as best option, while the preferred strategy for elimination was determined to be the combination of human and porcine mass drug administration combined with porcine vaccination of all eligible people and pigs, in a schedule of six iterations of four monthly interventions. These interventions are currently being field tested, combined with education. Several other hurdles to control, such as cost and socio-political factors and the need for an improved advocacy and awareness creation are discussed.

Overview of Taenia solium cysticercosis in West Africa

Human and porcine cysticercosis is endemic in West Africa, where epilepsy is relatively common, but rarely reported due to fear of stigmatization. Neurocysticercosis, caused by Taenia solium, tends to affect the poor in developing countries and control is hampered by inadequate infrastructure and financial resources coupled with lack of adequate information about its significance and distribution. The risk factors for human cysticercosis are closely associated with the characteristics of smallholder or backyard pig farming systems prevalent in this region. Poverty, ignorance and lack of political will militate against successful eradication, while tools for effective diagnosis, prevention and treatment, including vaccines for pigs, are not yet available in many countries. Cysticercosis was targeted for control by The World Health Organization global plan for 2008-2015; however, measures for control are yet to be undertaken in a coordinated manner in West Africa. Diagnostic tools, including neuroimaging facilities, should be strategically situated and made accessible to rural populations in West Africa. Community education in combination with a multipronged approach consisting of vaccination of pigs using TSOL18 vaccine and treatment with oxfendazole along with mass chemotherapy of humans with praziquantel could eliminate taeniasis and should be considered. In-depth and extensive epidemiological studies are required in West Africa in order to fully elucidate the prevalence of T. solium and to support more coordinated and effective control of human and porcine cysticercosis.

Estimating the association between being seropositive for cysticercosis and the prevalence of epilepsy and severe chronic headaches in 60 villages of rural Burkina Faso

Background

Individuals diagnosed with neurocysticercosis often present with epilepsy and sometimes with progressively worsening severe chronic headaches (WSCH). While cross-sectional associations between seropositivity to cysticercal antigens and epilepsy have been reported, few large scale studies have been conducted in West Africa and none have measured the association between seropositivity to cysticercal antigens and headaches. This study aimed at filling these knowledge gaps by estimating the strength of the cross-sectional association between seropositivity to cysticercal antigens and the prevalence of epilepsy and WSCH in 60 villages of Burkina Faso, West Africa.

Methodology/Principal findings

Baseline data from a cluster randomized controlled trial collected from January 2011 to February 2012 in 60 villages across three provinces in Burkina Faso were used. Between 78 and 80 individuals were screened for epilepsy and WSCH in each village, and those screened positive were confirmed by a physician. Seventy-five percent of all participants were asked to provide a blood sample to test for Taenia solium cysticercus circulating antigens. Hierarchical multivariable logistic models were used to measure the association between seropositivity to cysticercal antigens and epilepsy (lifetime and active) as well as WSCH. Among 3696 individuals who provided a blood sample, 145 were found to have epilepsy only, 140 WSCH only and 19 both. There were positive associations between seropositivity to cysticercal antigens and active epilepsy (prevalence odds ratio (POR): 2.40 (95%CI: 1.15–5.00)) and WSCH (POR: 2.59 (1.34–4.99)).

Conclusions/Significance

Our study is the first to demonstrate a cross-sectional association between seropositivity to cysticercal antigens and WSCH in a large community-based study conducted in West Africa. The measured cross-sectional association had a strength similar to the ones previously observed between seropositivity to cysticercal antigens and lifetime or active epilepsy. As a result, preventing new cysticercosis cases in communities may reduce the prevalence of these two important neurological disorders.

Taenia solium is a parasite that can be transmitted between humans and pigs in areas with poor sanitation and pig management practices. When this parasite infects the human brain, it can cause epilepsy or severe headaches. Our study aimed to measure the association between being seropositive to cysticercal antigens and having epilepsy (lifetime and active) or severe headaches in 60 villages of Burkina Faso. We found that active epilepsy and severe headaches were associated with seropositivity to cysticercal antigens. These results confirm prior studies which suggested an association between being seropositive for cysticercal antigens and these two neurological symptoms. Preventing cysticercosis could reduce new cases of these two neurological symptoms from occurring.

Recent advancements in the control of Taenia solium: A systematic review

The combined health and economic impact of Taenia solium urges for control and, if possible, elimination of this neglected parasitic zoonosis. Up till now there is still no consensus about the most cost-effective and feasible approaches for control. The objective of this systematic review is to identify and summarize the evidence in English scientific literature on the control and elimination of T. solium since 2014, based on the rapidly evolving field of evidence on control and elimination of T. solium. The search resulted in the identification of 458 records of which 31 were included, covering 13 field trials and 18 articles containing experimental data, mathematical models, and other information directly relevant the control of T. solium.

Recent field studies confirm that combinations of interventions or multiple rounds are more successful in obtaining rapid reductions in transmission and parasite occurrence, with the quick impact of the combination of human and pig treatment confirmed in a South Asian and Peruvian context. Moreover, elimination of transmission through a one-year intensive program, combining human and pig treatment/vaccination was described in a Peruvian study. Recent studies also provide more data on the positive impact of specific health education, as well as newly developed electronic educational tools, providing opportunities for area specific community-engaged participatory interventions.

Once control has been achieved, monitoring of migration of both potentially infected people and pigs from outside the control area is important for sustained disease control.

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Combined intervention field studies demonstrate sharp decreases in disease occurrence.

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New, specific, efficient, electronic educational tools are available.

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Elimination of Taenia solium in a Peruvian endemic area has been described.

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Integration of Taenia solium control in other NTD control programs can be effective.