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Background: Neurocysticercosis is a common helminthic infection of the central nervous system and an important cause of adult-onset epilepsy in endemic countries. However, few studies have examined associations between neurologic symptoms, serology and radiographic findings on a community-level. Methodology: We conducted a population-based study of resident’s ≥2 years old in a highly endemic village in Peru (pop. 454). We applied a 14 -question neurologic screening tool and evaluated serum for antibodies against Taenia solium cysticercosis using enzyme-linked immunoelectrotransfer blot (LLGP-EITB). We invited all residents ≥18 years old to have non-contrast computerized tomography (CT) of the head. Principal findings: Of the 385 residents who provided serum samples, 142 (36.9%) were seropositive. Of the 256 residents who underwent CT scan, 48 (18.8%) had brain calcifications consistent with NCC; 8/48 (17.0%) reported a history of headache and/or seizures. Exposure to T. solium is very common in this endemic community where 1 out of 5 residents had brain calcifications. However, the vast majority of people with calcifications were asymptomatic. Conclusion: This study reports a high prevalence of NCC infection in an endemic community in Peru and confirms that a large proportion of apparently asymptomatic residents have brain calcifications that could provoke seizures in the future. [ABSTRACT FROM AUTHOR]

Background: Taenia solium, a parasitic cestode that affects humans and pigs, is the leading cause of preventable epilepsy in the developing world. T. solium eggs are released into the environment through the stool of humans infected with an adult intestinal tapeworm (a condition called taeniasis), and cause cysticercosis when ingested by pigs or other humans. A control strategy to intervene within high-risk foci in endemic communities has been proposed as an alternative to mass antihelminthic treatment. In this ring strategy, antihelminthic treatment is targeted to humans and pigs residing within a 100 meter radius of a pig heavily-infected with cysticercosis. Our aim was to describe the roaming ranges of pigs in this region, and to evaluate whether the 100 meter radius rings encompass areas where risk factors for T. solium transmission, such as open human defecation and dense pig activity, are concentrated. Methodology/Principal Findings: In this study, we used Global Positioning System (GPS) devices to track pig roaming ranges in two rural villages of northern Peru. We selected 41 pigs from two villages to participate in a 48-hour tracking period. Additionally, we surveyed all households to record the locations of open human defecation areas. We found that pigs spent a median of 82.8% (IQR: 73.5, 94.4) of their time roaming within 100 meters of their homes. The size of home ranges varied significantly by pig age, and 93% of the total time spent interacting with open human defecation areas occurred within 100 meters of pig residences. Conclusions/Significance: These results indicate that 100 meter radius rings around heavily-infected pigs adequately capture the average pig’s roaming area (i.e., home range) and represent an area where the great majority of exposure to human feces occurs. [ABSTRACT FROM AUTHOR]

Background: Taenia solium is a major cause of preventable epilepsy in developing nations. Screening and treatment of human intestinal stage infection (taeniasis) within high-risk foci may reduce transmission and prevent epilepsy by limiting human exposure to infective eggs. We piloted a ring-strategy that involves screening and treatment for taeniasis among households located nearby pigs heavily-infected with the larval stage (cysticercosis). These pigs mark areas of increased transmission and can be identified by tongue examination. Methodology: We selected two villages in northern Peru for a controlled prospective interventional cohort pilot study. In the intervention village (1,058 residents) we examined the tongues of all pigs every 4 months for nodules characteristic of cysticercosis. We then screened all residents living within 100-meters of any tongue-positive pig using enzyme-linked immunosorbent assay to detect Taenia antigens in stool. Residents with taeniasis were treated with niclosamide. In both the intervention and control (753 residents) we measured incidence of exposure by sampling the pig population every 4 months for serum antibodies against cysticercosis using enzyme-linked immunoelectrotransfer blot. Principal Findings: Baseline seroincidence among pigs born during the study was 22.6 cases per 100 pigs per-month (95% confidence interval [CI] 17.0–30.0) in the intervention and 18.1 (95% CI 12.7–25.9) in the control. After one year we observed a 41% reduction in seroincidence in the intervention village compared to baseline (incidence rate ratio 0.59, 95% CI 0.41–0.87) while the seroincidence in the control village remained unchanged. At study end, the prevalence of taeniasis was nearly 4 times lower in the intervention than in the control (prevalence ratio 0.28, 95% CI 0.08–0.91). Conclusions/Significance: Ring-screening reduced transmission of T. solium in this pilot study and may provide an effective and practical approach for regions where resources are limited. However, this strategy requires validation in larger populations over a greater period of time. Author Summary: Taenia solium is a zoonotic parasite which infects humans and pigs resulting in the cysticercosis/taeniasis duo of neglected tropical diseases. It is commonly known as the pork tapeworm. Infection of the human brain with this parasite causes up to a third of epilepsy in Latin America, Asia and Africa. Infection of pigs is a food-safety issue, as consumption of contaminated pork results in intestinal tapeworm infection in humans who may then transmit the parasite to others. Pig infection also results in economic harm to small landowners who cannot sell the contaminated pork. Despite increasing worldwide attention to these diseases, sustainable and effective control strategies have been elusive. One possible approach is to direct limited screening and treatment resources to specific subpopulations which have the highest risk of infection. In this study we found that screening for intestinal tapeworms among people who live nearby a heavily-infected pig reduced transmission of the parasite in the overall community by 40% over one year. This practical strategy could be implemented as a potentially sustainable community-based intervention in the poor rural regions of world where the disease is endemic. [ABSTRACT FROM AUTHOR]

Background: Neurocysticercosis is a leading cause of preventable epilepsy in the developing world. Sustainable community-based interventions are urgently needed to control transmission of the causative parasite, Taenia solium. We examined the geospatial relationship between live pigs with visible cysticercotic cysts on their tongues and humans with adult intestinal tapeworm infection (taeniasis) in a rural village in northern Peru. The objective was to determine whether tongue-positive pigs could indicate high-risk geographic foci for taeniasis to guide targeted screening efforts. This approach could offer significant benefit compared to mass intervention. Methods: We recorded geographic coordinates of all village houses, collected stool samples from all consenting villagers, and collected blood and examined tongues of all village pigs. Stool samples were processed by enzyme-linked immunosorbent assay (ELISA) for presence of Taenia sp. coproantigens indicative of active taeniasis; serum was processed by enzyme-linked immunoelectrotransfer blot for antibodies against T. solium cysticercosis (EITB LLGP) and T. solium taeniasis (EITB rES33). Findings: Of 548 pigs, 256 (46.7%) were positive for antibodies against cysticercosis on EITB LLGP. Of 402 fecal samples, 6 (1.5%) were positive for the presence of Taenia sp. coproantigens. The proportion of coproantigen-positive individuals differed significantly between residents living within 100-meters of a tongue-positive pig (4/79, 5.1%) and residents living >100 meters from a tongue-positive pig (2/323, 0.6%) (p = 0.02). The prevalence of taeniasis was >8 times higher among residents living within 100 meters of a tongue-positive pig compared to residents living outside this range (adjusted PR 8.1, 95% CI 1.4–47.0). Conclusions: Tongue-positive pigs in endemic communities can indicate geospatial foci in which the risk for taeniasis is increased. Targeted screening or presumptive treatment for taeniasis within these high-risk foci may be an effective and practical control intervention for rural endemic areas. Author Summary: Taenia solium, aka the pork tapeworm, is an important cause of epilepsy in developing nations. People with intestinal tapeworms, a condition known as taeniasis, pass infectious eggs in their feces which contaminate the environment. These eggs can cause serious disease in both humans and pigs if they are ingested. Treating taeniasis is one way to potentially control transmission of the parasite in affected communities. However, this is difficult because people with taeniasis usually have no symptoms and therefore don't know they are infected. As a result, control programs may resort to offering treatment to entire communities in order to reach a few tapeworm carriers. Focusing detection and treatment on high-risk subgroups is another approach which might reduce unnecessary treatments. In this study, we found that people with taeniasis are more likely to be found living nearby pigs with visible signs of infection, specifically tapeworm cysts on their tongues. This suggests that routine tongue examination by pig owners and buyers could identify neighborhoods where detection and treatment of taeniasis may be more efficient. [ABSTRACT FROM AUTHOR]

Taenia solium is the most common helminthic infection of the central nervous system and a leading cause of epilepsy in developing nations. Little is known about neurocysticercosis in refugees from Southeast Asia which is endemic for T solium. We present two cases in a single household of refugees from Burma. [ABSTRACT FROM AUTHOR]

Background: Taeniasis and cysticercosis are major causes of seizures and epilepsy. Infection by the causative parasite Taenia solium requires transmission between humans and pigs. The disease is considered to be eradicable, but data on attempts at regional elimination are lacking. We conducted a three-phase control program in Tumbes, Peru, to determine whether regional elimination would be feasible.Methods: We systematically tested and compared elimination strategies to show the feasibility of interrupting the transmission of T. solium infection in a region of highly endemic disease in Peru. In phase 1, we assessed the effectiveness and feasibility of six intervention strategies that involved screening of humans and pigs, antiparasitic treatment, prevention education, and pig replacement in 42 villages. In phase 2, we compared mass treatment with mass screening (each either with or without vaccination of pigs) in 17 villages. In phase 3, we implemented the final strategy of mass treatment of humans along with the mass treatment and vaccination of pigs in the entire rural region of Tumbes (107 villages comprising 81,170 people and 55,638 pigs). The effect of the intervention was measured after phases 2 and 3 with the use of detailed necropsy to detect pigs with live, nondegenerated cysts capable of causing new infection. The necropsy sampling was weighted in that we preferentially included more samples from seropositive pigs than from seronegative pigs.Results: Only two of the strategies implemented in phase 1 resulted in limited control over the transmission of T. solium infection, which highlighted the need to intensify the subsequent strategies. After the strategies in phase 2 were implemented, no cyst that was capable of further transmission of T. solium infection was found among 658 sampled pigs. One year later, without further intervention, 7 of 310 sampled pigs had live, nondegenerated cysts, but no infected pig was found in 11 of 17 villages, including all the villages in which mass antiparasitic treatment plus vaccination was implemented. After the final strategy was implemented in phase 3, a total of 3 of 342 pigs had live, nondegenerated cysts, but no infected pig was found in 105 of 107 villages.Conclusions: We showed that the transmission of T. solium infection was interrupted on a regional scale in a highly endemic region in Peru. (Funded by the Bill and Melinda Gates Foundation and others.). [ABSTRACT FROM AUTHOR]

Mercury, a potent toxin that poses serious risks to human health, particularly for pregnant women and young children, is widely present due to artisanal and small-scale gold mining (ASGM), which impacts water quality. The objective of this study was to evaluate methylmercury exposure among pregnant women in communities downstream from ASGM sites. We characterized hair total mercury (THg) concentrations among 148 pregnant women across 24 communities in the Tumbes region of Peru, downstream from ASGM sites in Ecuador. Using purposeful sampling, we classified communities into three exposure risk zones: Puyango-Tumbes River watershed, Coast, and Zarumilla. The mean THg concentration was 2.08 µg/g ± 1.36, with 45% of participants (67/148) exceeding UNEP/WHO exposure limits (>2.0 µg/g). The median was 1.84 with an interquartile range (IQR) from 1.01 to 2.83. Median THg levels were significantly higher in the Puyango-Tumbes River region (2.72 µg/g; IQR: 1.66-3.55) compared with Zarumilla (1.61 µg/g; IQR: 0.67-2.63; P = 0.001) and to the Coast (1.71 µg/g; IQR: 1.13-2.50; P = 0.01), suggesting that living close to the Puyango-Tumbes River may be associated with a higher mercury exposure risk. After controlling for potential confounders, individuals in the Puyango-Tumbes watershed exhibited a significant 57% higher expected geometric mean of hair THg compared with Zarumilla (95% CI: 0.1-146.2%). These findings underscore the importance of identifying high-risk regional populations and ongoing biomonitoring of the Puyango-Tumbes River watershed.

Background: Mass drug administration (MDA) with niclosamide (NSM) can be used to control taeniasis, the cause of neurocysticercosis. NSM is 84.3% effective against taeniasis and is considered safe as it is not absorbed from the intestinal tract. However, information on its safety and effectiveness during MDA is limited. We evaluated the effectiveness of NSM and reported adverse events (AEs) during a cysticercosis elimination program in Tumbes, Peru., Methods: Three rounds of NSM at 4-month intervals were offered to 77,397 eligible residents. We revisited all participants in their homes 72 h after each round to collect information regarding AEs. We also collected post-treatment stool samples to diagnose taeniasis after the first round, followed by a second sample at 30 days from those infected to evaluate NSM's effectiveness., Findings: During implementation, 68,751 individuals were administered at least one dose of NSM (mean age 29 years, SD 20; 52% male), and 65,551 (95.3%) were visited post-treatment. 988 (1.5%) reported experiencing at least one AE. Almost all AEs (99.2%) were of mild intensity, with no severe AEs recorded. Of 211 participants diagnosed with taeniasis, 188 provided a follow-up stool sample 30-days after treatment and 141 were cured (treatment effectiveness 75.0%). Older age and higher coproantigen levels were significantly associated with treatment failure., Interpretation: MDA with NSM is safe in Taenia solium endemic settings. However, the effectiveness following one dose is lower than expected, which suggests additional treatment may be necessary to enhance the infection control efforts., Funding: The Bill and Melinda Gates Foundation., Competing Interests: RG, PV, CM, and LMM were partially supported by the US National Institutes of Health, the Fogarty International Center (TW001140), AGL was supported by Emerge, the Emerging Diseases Epidemiology Research Training of the US National Institutes of Health, the Fogarty International Center (D43 TW007393), and MTW was supported by the National Center for Advancing Translational Sciences of the US National Institutes of Health under award number (TL1TR00237). HG was supported by a Wellcome Trust International Senior Research Fellowship in Public Health and Tropical Medicine. All authors declare no conflicts of interests., (© 2024 The Author(s).)

Enzyme-linked immunoelectrotransfer blot (EITB) detects antibodies against seven Taenia solium larvae antigens in three protein families (GP50, T24/42, and 8-kDa) with different structures and functions. EITB banding patterns against these antigens in pigs provide information about the course of infection and may discriminate viable cysticercosis. We analyzed the banding patterns and infection outcomes (presence of viable cysts, degenerated cysts, and any cysts) of 512 rural pigs. Banding patterns were grouped into homogenous classes using latent class analysis, and relationships with infection outcomes were assessed. Four classes were identified: 1 ( n = 308, EITB-negative or positive for the GP50 family), 2 ( n = 127, positive for GP50 (GP50 family), GP42-39 and GP24 (T24/42 family), but negative for 8-kDa antigens), 3 ( n = 22, positive for GP50 and T24/42 antigens (GP42-39 and GP24), as well as to 8-kDa bands GP13, GP14, and GP18, but negative for GP21), and 4 ( n = 55, positive for GP50 and T24/42 antigens, as well as to 8-kDa antigens GP21 and GP18 in combination). Pigs in classes 3 and 4 were more likely to have viable cysts (72.6% and 96.4%, respectively) than pigs in classes 1 and 2 (0.7% and 27.6%, respectively; p < 0.001). The number of infections with any cysts was higher in classes 3 and 4 (77.3% and 98.2%, respectively) and lower in classes 2 and 1 (34.7% and 4.9%, respectively; p < 0.001). Pigs with viable cysts represented >90% of pigs with any cysts in classes 3 and 4 (94.1% and 98.2%, respectively), while degenerated cysts were frequent among pigs with any cysts in classes 1, 3, and 2 (86.7%, 47.1%, and 43.2%, respectively; p < 0.001). EITB banding patterns strongly correlate with cysticercosis infection status in rural pigs, with classes 3 and 4 being more predictive of viable infections.

Introduction: The Taenia solium tapeworm is responsible for cysticercosis, a neglected tropical disease presenting as larvae in the body of a host following taenia egg ingestion. Neurocysticercosis (NCC), the name of the disease when it affects the human central nervous system, is a major cause of epilepsy in developing countries, and can also cause intracranial hypertension, hydrocephalus and death. Simulation models can help identify the most cost-effective interventions before their implementation. Modelling NCC should enable the comparison of a broad range of interventions, from treatment of human taeniasis (presence of an adult taenia worm in the human intestine) to NCC mitigation. It also allows a focus on the actual impact of the disease, rather than using proxies as is the case for other models., Methods: This agent-based model is the first model that simulates human NCC and associated pathologies. It uses the output of another model, CystiAgent, which simulates the evolution of pig cysticercosis and human taeniasis, adding human and cyst agents, including a model of cyst location and stage, human symptoms, and treatment. CystiHuman also accounts for delays in the appearance of NCC-related symptoms. It comprises three modules detailing cyst development, seizure probability and timing, and intracranial hypertension/hydrocephalus, respectively. It has been implemented in Java MASON and calibrated in three endemic villages in Peru, then applied to another village (Rica Playa) to compare simulation results with field data in that village., Results and Discussion: Despite limitations in available field data, parameter values found through calibration are plausible and simulated outcomes in Rica Playa are close to actual values for NCC prevalence and the way it increases with age and cases with single lesions. Initial simulations further suggest that short-term interventions followed by a rapid increase in taeniasis prevalence back to original levels may have limited impacts on NCC prevalence., Competing Interests: The authors have declared that no competing interests exist.

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.