The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Phillip A Newmark - One of the best experts on this subject based on the ideXlab platform.
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region specific regulation of stem cell driven regeneration in tapeworms
eLife, 2019Co-Authors: Tania Rozario, Edward B Quinn, Richard E Davis, Phillip A Newmark, Jianbin WangAbstract:Many worms have remarkable abilities to regrow and repair their bodies. The parasitic tapeworms, for example, can reach lengths of several meters and grow much more quickly than tissues in humans and other complex animals. This growth allows tapeworms to counteract the continual loss of the segments that make up their bodies, known as proglottids – a process that happens throughout their lives. The capacity to regenerate thousands of lost body segments and maintain an overall body length suggests that tapeworms have groups of stem cells in their body which can grow and divide to produce the new body parts. Yet, regeneration in tapeworms has not been closely studied. Rozario et al. have now examined Hymenolepsis diminuta, the rat tapeworm, and identified the neck of the tapeworm as crucial for its ability to regrow lost body segments. Further analysis identified two genes, zmym3 and pogzl, that are essential for cell division during tapeworm growth. However, Rozario et al. showed that these genes are active elsewhere in the worm’s body and that it is the conditions found specifically in the tapeworm’s neck that create the right environment for stem cells to enable regeneration of new segments. Tapeworms provide a valuable example for studying the growth of stem cells and these findings highlight the important role that the cells’ surroundings play in driving stem cell activity. These findings could also lead to new insights into how stem cells behave in other animals and could potentially lead to new approaches to prevent or treat tapeworm infections.
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region specific regulation of stem cell driven regeneration in tapeworms
bioRxiv, 2018Co-Authors: Tania Rozario, Edward B Quinn, Richard E Davis, Phillip A Newmark, Jianbin WangAbstract:Tapeworms grow at rates that rival all metazoan tissues, including during embryonic and neoplastic growth. For example, the rat intestinal tapeworm, Hymenolepis diminuta , produces up to 2,200 proglottids (segments), increasing in length up to 3,400 fold, and weight up to 1.8 million fold within the first 15 days of infection. Tapeworms also regenerate: they shed large parts of their body, releasing their embryos to continue their life cycle, yet are able to continuously replenish proglottids and maintain an equilibrium length. Such remarkable growth and regeneration are fueled by adult somatic stem cells, which have yet to be characterized molecularly. Using H. diminuta as a laboratory model, we find that regeneration is limited to the tapeworm neck, making this tissue a prime source to identify stem cell genes. Using transcriptomic analyses and RNA interference (RNAi), we characterize and functionally validate the first molecular regulators of tapeworm growth and regeneration. However, we find no evidence that stem cells are restricted to the regeneration-competent neck. Instead, we find that lethally irradiated tapeworms can be rescued from death when cells from both regeneration-competent and regeneration-incompetent regions are transplanted into the neck. Furthermore, the persistence of regenerative ability over time requires signal(s) from the head, even though the head itself cannot regenerate and the head is not necessary for initial regeneration. Together, the head and neck tissue provide a microenvironment that regulates stem cells to enable region-specific regeneration in this tapeworm.
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A confocal microscopy-based atlas of tissue architecture in the tapeworm Hymenolepis diminuta.
Experimental Parasitology, 2015Co-Authors: Tania Rozario, Phillip A NewmarkAbstract:Abstract Tapeworms are pervasive and globally distributed parasites that infect millions of humans and livestock every year, and are the causative agents of two of the 17 neglected tropical diseases prioritized by the World Health Organization. Studies of tapeworm biology and pathology are often encumbered by the complex life cycles of disease-relevant tapeworm species that infect hosts such as foxes, dogs, cattle, pigs, and humans. Thus, studies of laboratory models can help overcome the practical, ethical, and cost-related difficulties faced by tapeworm parasitologists. The rat intestinal tapeworm Hymenolepis diminuta is easily reared in the laboratory and has the potential to enable modern molecular-based experiments that will greatly contribute to our understanding of multiple aspects of tapeworm biology, such as growth and reproduction. As part of our efforts to develop molecular tools for experiments on H. diminuta , we have characterized a battery of lectins, antibodies, and common stains that label different tapeworm tissues and organ structures. Using confocal microscopy, we have assembled an “atlas” of H. diminuta organ architecture that will be a useful resource for helminthologists. The methodologies we describe will facilitate characterization of loss-of-function perturbations using H. diminuta . This toolkit will enable a greater understanding of fundamental tapeworm biology that may elucidate new therapeutic targets toward the eradication of these parasites.
Robert H Gilman - One of the best experts on this subject based on the ideXlab platform.
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clustering of necropsy confirmed porcine cysticercosis surrounding taenia solium tapeworm carriers in peru
American Journal of Tropical Medicine and Hygiene, 2019Co-Authors: Andres G Lescano, Ian W Pray, Armando E Gonzalez, Robert H Gilman, Victor C W Tsang, Ricardo Gamboa, Claudia M GuezalaAbstract:The pork tapeworm, Taenia solium, is among the leading causes of preventable epilepsy in the world and is common in rural areas of developing countries where sanitation is limited and pigs have access to human feces. Prior studies in rural villages of Peru have observed clusters of T. solium cysticercosis among pigs that live near human tapeworm carriers. Such spatial analyses, however, have been limited by incomplete participation and substandard diagnostic tests. In this study, we evaluated the association between necropsy-confirmed cysticercosis in pigs and their distance to T. solium tapeworm carriers in six villages in northern Peru. A total of six (1.4%) tapeworm carriers were detected using copro-antigen enzyme-linked immunosorbent assay and seven of 10 (70%) pigs belonging to the tapeworm carriers were found with viable cyst infection on necropsy. This was significantly greater than the prevalence of viable cyst infection among pigs living 500 m (0.5%) from a tapeworm carrier (P 10 viable cysts, degenerated cyst infection, and serological outcomes. This investigation confirms that porcine cysticercosis clusters strongly around tapeworm carriers in endemic rural regions of northern Peru and supports interventions that target these hotspots.
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taenia solium infection in peru a collaboration between peace corps volunteers and researchers in a community based study
PLOS ONE, 2014Co-Authors: Nathaniel S Watts, Hector H Garcia, Manuela Verastegui, Monica Pajuelo, Taryn Clark, Mariacristina I Loader, Charles R Sterling, Jon S Friedland, Robert H GilmanAbstract:Background Neurocysticercosis is a leading cause of seizures and epilepsy in most of the world, and it occurs when Taenia solium larval cysts infect the central nervous system. T. solium tapeworm infection is endemic in much of Peru, but there are scarce data on the prevalence in many rural highland communities where it is likely to be hyper-endemic. Peace Corps Volunteers live and work in these communities; however, to our knowledge, they have not been used to facilitate public health research. Materials and Methods We utilized Peace Corps Volunteers to estimate the prevalence of T. solium tapeworm infection in seven rural communities in northern Peru. A convenience non-random sampling frame was used. Peace Corps Volunteers facilitated the collection of stool samples (N = 2,328), which were analyzed by sedimentation and microscopy. Niclosamide treatment and purgation preceded species identification, which was done by PCR-REA. Results Taenia sp. egg-positive stool samples were found in three of the seven communities we surveyed. The overall prevalence of Taenia sp. egg positivity was 2.1% (49/2,328) (95% CI = 1.6–2.8%) with prevalence up to 4.3% (42/977) (95% CI = 3.1–5.8%) by community. All 34 of the specimens tested by PCR-REA were T. solium. The overall prevalence of T. solium tapeworm infection was 1.5% (34/2,328) (95% CI = 1.0–2.0%). Prevalence up to 2.9% (28/977) (95% CI = 1.9–4.1%) by community was observed. Conclusion/Significance This study recorded high T. solium tapeworm prevalence, and identified hyper-endemic rural communities. It demonstrates that synergy between researchers and Peace Corps Volunteers can be an effective means to conducting large-scale, community-based studies in remote areas of Peru.
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taenia solium cysticercosis hotspots surrounding tapeworm carriers clustering on human seroprevalence but not on seizures
PLOS Neglected Tropical Diseases, 2009Co-Authors: Andres G Lescano, Robert H Gilman, Victor C W Tsang, Hector H Garcia, Cesar M Gavidia, Silvia RodriguezAbstract:Background: Neurocysticercosis accounts for 30%–50% of all late-onset epilepsy in endemic countries. We assessed the clustering patterns of Taenia solium human cysticercosis seropositivity and seizures around tapeworm carriers in seven rural communities in Peru. Methodology: The presence of T. solium–specific antibodies was defined as one or more positive bands in the enzymelinked immunoelectrotransfer blot (EITB). Neurocysticercosis-related seizures cases were diagnosed clinically and had positive neuroimaging or EITB. Principal Findings: Eleven tapeworm carriers were identified by stool microscopy. The seroprevalence of human cysticercosis was 24% (196/803). Seroprevalence was 21% .50 m from a carrier and increased to 32% at 1–50 m (p=0.047), and from that distance seroprevalence had another significant increase to 64% at the homes of carriers (p=0.004). Seizure prevalence was 3.0% (25/837) but there were no differences between any pair of distance ranges (p=0.629, Wald test 2 degrees of freedom). Conclusion/Significance: We observed a significant human cysticercosis seroprevalence gradient surrounding current tapeworm carriers, although cysticercosis-related seizures did not cluster around carriers. Due to differences in the timing of the two outcomes, seroprevalence may reflect recent T. solium exposure more accurately than seizure frequency.
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swine cysticercosis hotspots surrounding taenia solium tapeworm carriers
American Journal of Tropical Medicine and Hygiene, 2007Co-Authors: Andres G Lescano, Robert H Gilman, Victor C W Tsang, Claudia M Guezala, Hector H Garcia, Cesar M Gavidia, Silvia Rodriguez, Lawrence H MoultonAbstract:We estimated the Taenia solium swine cysticercosis risk gradient surrounding tapeworm carriers in seven rural communities in Peru. At baseline, the prevalences of taeniasis by microscopy and swine cysticercosis by serology were 1.2% (11 of 898) and 30.8% (280 of 908), respectively. The four-month cumulative seroincidence was 9.8% (30 of 307). The unadjusted swine seroprevalence and seroincidence rates increased exponentially by 12.0% (95% confidence [CI] = 9.7-14.3%) and 32.8% (95% CI = 25.0-41.0%), respectively when distance to carriers decreased by half. Swine seroprevalence was 18.4% at > 500 meters from a carrier, 36.5% between 51 and 500 meters, and 68.9% within 50 meters (P < 0.001). Swine seroincidence also displayed a strong gradient near tapeworm carriers (3.8%, 12.2%, and 44.0%; P < 0.001). Within 50 meters, swine seroprevalence appeared unaffected if the owners harbored tapeworms, although pigs owned by a tapeworm carrier had a four times higher seroincidence compared with other pigs (P = 0.005). In rural areas, swine cysticercosis occurs in high-risk hotspots around carriers where control interventions could be delivered.
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development of a serologic assay to detect taenia solium taeniasis
American Journal of Tropical Medicine and Hygiene, 1999Co-Authors: Patricia P Wilkins, Armando E Gonzalez, Robert H Gilman, Hector H Garcia, J C Allan, Manuela Verastegui, Mariela Acosta, Adam G Eason, Victor C W TsangAbstract:We developed a serologic assay to identify adult Taenia solium tapeworm carriers using excretory/secretory (TSES) antigens collected from in vitro cultured T. solium tapeworms. To identify taeniasis-specific antigens we used an immunoblot assay with serum samples from T. solium tapeworm carriers and cysticercosis patients. Antigens were identified that reacted with antibodies present in serum samples from taeniasis cases and not with those from cysticercosis patients. Using serum samples collected from persons with confirmed T. solium tapeworm infections, the test was determined to be 95% (69 of 73) sensitive. Serum samples (n = 193) from persons with other parasitic infections, including T. saginata tapeworm infections, do not contain cross-reacting antibodies to TSES, indicating that the assay is 100% specific. These data suggest that the immunoblot assay using TSES antigens can be used to identify persons with current or recent T. solium tapeworm infections and provides a new, important tool for epidemiologic purposes, including control and prevention strategies.
Andres G Lescano - One of the best experts on this subject based on the ideXlab platform.
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clustering of necropsy confirmed porcine cysticercosis surrounding taenia solium tapeworm carriers in peru
American Journal of Tropical Medicine and Hygiene, 2019Co-Authors: Andres G Lescano, Ian W Pray, Armando E Gonzalez, Robert H Gilman, Victor C W Tsang, Ricardo Gamboa, Claudia M GuezalaAbstract:The pork tapeworm, Taenia solium, is among the leading causes of preventable epilepsy in the world and is common in rural areas of developing countries where sanitation is limited and pigs have access to human feces. Prior studies in rural villages of Peru have observed clusters of T. solium cysticercosis among pigs that live near human tapeworm carriers. Such spatial analyses, however, have been limited by incomplete participation and substandard diagnostic tests. In this study, we evaluated the association between necropsy-confirmed cysticercosis in pigs and their distance to T. solium tapeworm carriers in six villages in northern Peru. A total of six (1.4%) tapeworm carriers were detected using copro-antigen enzyme-linked immunosorbent assay and seven of 10 (70%) pigs belonging to the tapeworm carriers were found with viable cyst infection on necropsy. This was significantly greater than the prevalence of viable cyst infection among pigs living 500 m (0.5%) from a tapeworm carrier (P 10 viable cysts, degenerated cyst infection, and serological outcomes. This investigation confirms that porcine cysticercosis clusters strongly around tapeworm carriers in endemic rural regions of northern Peru and supports interventions that target these hotspots.
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taenia solium cysticercosis hotspots surrounding tapeworm carriers clustering on human seroprevalence but not on seizures
PLOS Neglected Tropical Diseases, 2009Co-Authors: Andres G Lescano, Robert H Gilman, Victor C W Tsang, Hector H Garcia, Cesar M Gavidia, Silvia RodriguezAbstract:Background: Neurocysticercosis accounts for 30%–50% of all late-onset epilepsy in endemic countries. We assessed the clustering patterns of Taenia solium human cysticercosis seropositivity and seizures around tapeworm carriers in seven rural communities in Peru. Methodology: The presence of T. solium–specific antibodies was defined as one or more positive bands in the enzymelinked immunoelectrotransfer blot (EITB). Neurocysticercosis-related seizures cases were diagnosed clinically and had positive neuroimaging or EITB. Principal Findings: Eleven tapeworm carriers were identified by stool microscopy. The seroprevalence of human cysticercosis was 24% (196/803). Seroprevalence was 21% .50 m from a carrier and increased to 32% at 1–50 m (p=0.047), and from that distance seroprevalence had another significant increase to 64% at the homes of carriers (p=0.004). Seizure prevalence was 3.0% (25/837) but there were no differences between any pair of distance ranges (p=0.629, Wald test 2 degrees of freedom). Conclusion/Significance: We observed a significant human cysticercosis seroprevalence gradient surrounding current tapeworm carriers, although cysticercosis-related seizures did not cluster around carriers. Due to differences in the timing of the two outcomes, seroprevalence may reflect recent T. solium exposure more accurately than seizure frequency.
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swine cysticercosis hotspots surrounding taenia solium tapeworm carriers
American Journal of Tropical Medicine and Hygiene, 2007Co-Authors: Andres G Lescano, Robert H Gilman, Victor C W Tsang, Claudia M Guezala, Hector H Garcia, Cesar M Gavidia, Silvia Rodriguez, Lawrence H MoultonAbstract:We estimated the Taenia solium swine cysticercosis risk gradient surrounding tapeworm carriers in seven rural communities in Peru. At baseline, the prevalences of taeniasis by microscopy and swine cysticercosis by serology were 1.2% (11 of 898) and 30.8% (280 of 908), respectively. The four-month cumulative seroincidence was 9.8% (30 of 307). The unadjusted swine seroprevalence and seroincidence rates increased exponentially by 12.0% (95% confidence [CI] = 9.7-14.3%) and 32.8% (95% CI = 25.0-41.0%), respectively when distance to carriers decreased by half. Swine seroprevalence was 18.4% at > 500 meters from a carrier, 36.5% between 51 and 500 meters, and 68.9% within 50 meters (P < 0.001). Swine seroincidence also displayed a strong gradient near tapeworm carriers (3.8%, 12.2%, and 44.0%; P < 0.001). Within 50 meters, swine seroprevalence appeared unaffected if the owners harbored tapeworms, although pigs owned by a tapeworm carrier had a four times higher seroincidence compared with other pigs (P = 0.005). In rural areas, swine cysticercosis occurs in high-risk hotspots around carriers where control interventions could be delivered.
Hector H Garcia - One of the best experts on this subject based on the ideXlab platform.
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spatial relationship between taenia solium tapeworm carriers and necropsy cyst burden in pigs
PLOS Neglected Tropical Diseases, 2017Co-Authors: Ian W Pray, Ricardo Gamboa, Viterbo Ayvar, Claudio Muro, Luz M Moyano, Victor Benavides, Robert H Flecker, Hector H Garcia, Seth E OnealAbstract:Background Taenia solium, a parasite that affects humans and pigs, is the leading cause of preventable epilepsy in the developing world. Geographic hotspots of pigs testing positive for serologic markers of T. solium exposure have been observed surrounding the locations of human tapeworm carriers. This clustered pattern of seropositivity in endemic areas formed the basis for geographically targeted control interventions, which have been effective at reducing transmission. In this study, we further explore the spatial relationship between human tapeworm carriers and infected pigs using necroscopic examination as a quantitative gold-standard diagnostic to detect viable T. solium cyst infection in pigs. Methodology/principal findings We performed necroscopic examinations on pigs from 7 villages in northern Peru to determine the number of viable T. solium cysts in each pig. Participating humans in the study villages were tested for T. solium tapeworm infection (i.e., taeniasis) with an ELISA coproantigen assay, and the distances from each pig to its nearest human tapeworm carrier were calculated. We assessed the relationship between proximity to a tapeworm carrier and the prevalence of light, moderate, and heavy cyst burden in pigs. The prevalence of pig infection was greatest within 50 meters of a tapeworm carrier and decreased monotonically as distance increased. Pigs living less than 50 meters from a human tapeworm carrier were 4.6 times more likely to be infected with at least one cyst than more distant pigs. Heavier cyst burdens, however, were not more strongly associated with proximity to tapeworm carriers than light cyst burdens. Conclusion/significance Our study shows that human tapeworm carriers and pigs with viable T. solium cyst infection are geographically correlated in endemic areas. This finding supports control strategies that treat humans and pigs based on their proximity to other infected individuals. We did not, however, find sufficient evidence that heavier cyst burdens in pigs would serve as improved targets for geographically focused control interventions.
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taenia solium infection in peru a collaboration between peace corps volunteers and researchers in a community based study
PLOS ONE, 2014Co-Authors: Nathaniel S Watts, Hector H Garcia, Manuela Verastegui, Monica Pajuelo, Taryn Clark, Mariacristina I Loader, Charles R Sterling, Jon S Friedland, Robert H GilmanAbstract:Background Neurocysticercosis is a leading cause of seizures and epilepsy in most of the world, and it occurs when Taenia solium larval cysts infect the central nervous system. T. solium tapeworm infection is endemic in much of Peru, but there are scarce data on the prevalence in many rural highland communities where it is likely to be hyper-endemic. Peace Corps Volunteers live and work in these communities; however, to our knowledge, they have not been used to facilitate public health research. Materials and Methods We utilized Peace Corps Volunteers to estimate the prevalence of T. solium tapeworm infection in seven rural communities in northern Peru. A convenience non-random sampling frame was used. Peace Corps Volunteers facilitated the collection of stool samples (N = 2,328), which were analyzed by sedimentation and microscopy. Niclosamide treatment and purgation preceded species identification, which was done by PCR-REA. Results Taenia sp. egg-positive stool samples were found in three of the seven communities we surveyed. The overall prevalence of Taenia sp. egg positivity was 2.1% (49/2,328) (95% CI = 1.6–2.8%) with prevalence up to 4.3% (42/977) (95% CI = 3.1–5.8%) by community. All 34 of the specimens tested by PCR-REA were T. solium. The overall prevalence of T. solium tapeworm infection was 1.5% (34/2,328) (95% CI = 1.0–2.0%). Prevalence up to 2.9% (28/977) (95% CI = 1.9–4.1%) by community was observed. Conclusion/Significance This study recorded high T. solium tapeworm prevalence, and identified hyper-endemic rural communities. It demonstrates that synergy between researchers and Peace Corps Volunteers can be an effective means to conducting large-scale, community-based studies in remote areas of Peru.
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taenia solium cysticercosis hotspots surrounding tapeworm carriers clustering on human seroprevalence but not on seizures
PLOS Neglected Tropical Diseases, 2009Co-Authors: Andres G Lescano, Robert H Gilman, Victor C W Tsang, Hector H Garcia, Cesar M Gavidia, Silvia RodriguezAbstract:Background: Neurocysticercosis accounts for 30%–50% of all late-onset epilepsy in endemic countries. We assessed the clustering patterns of Taenia solium human cysticercosis seropositivity and seizures around tapeworm carriers in seven rural communities in Peru. Methodology: The presence of T. solium–specific antibodies was defined as one or more positive bands in the enzymelinked immunoelectrotransfer blot (EITB). Neurocysticercosis-related seizures cases were diagnosed clinically and had positive neuroimaging or EITB. Principal Findings: Eleven tapeworm carriers were identified by stool microscopy. The seroprevalence of human cysticercosis was 24% (196/803). Seroprevalence was 21% .50 m from a carrier and increased to 32% at 1–50 m (p=0.047), and from that distance seroprevalence had another significant increase to 64% at the homes of carriers (p=0.004). Seizure prevalence was 3.0% (25/837) but there were no differences between any pair of distance ranges (p=0.629, Wald test 2 degrees of freedom). Conclusion/Significance: We observed a significant human cysticercosis seroprevalence gradient surrounding current tapeworm carriers, although cysticercosis-related seizures did not cluster around carriers. Due to differences in the timing of the two outcomes, seroprevalence may reflect recent T. solium exposure more accurately than seizure frequency.
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swine cysticercosis hotspots surrounding taenia solium tapeworm carriers
American Journal of Tropical Medicine and Hygiene, 2007Co-Authors: Andres G Lescano, Robert H Gilman, Victor C W Tsang, Claudia M Guezala, Hector H Garcia, Cesar M Gavidia, Silvia Rodriguez, Lawrence H MoultonAbstract:We estimated the Taenia solium swine cysticercosis risk gradient surrounding tapeworm carriers in seven rural communities in Peru. At baseline, the prevalences of taeniasis by microscopy and swine cysticercosis by serology were 1.2% (11 of 898) and 30.8% (280 of 908), respectively. The four-month cumulative seroincidence was 9.8% (30 of 307). The unadjusted swine seroprevalence and seroincidence rates increased exponentially by 12.0% (95% confidence [CI] = 9.7-14.3%) and 32.8% (95% CI = 25.0-41.0%), respectively when distance to carriers decreased by half. Swine seroprevalence was 18.4% at > 500 meters from a carrier, 36.5% between 51 and 500 meters, and 68.9% within 50 meters (P < 0.001). Swine seroincidence also displayed a strong gradient near tapeworm carriers (3.8%, 12.2%, and 44.0%; P < 0.001). Within 50 meters, swine seroprevalence appeared unaffected if the owners harbored tapeworms, although pigs owned by a tapeworm carrier had a four times higher seroincidence compared with other pigs (P = 0.005). In rural areas, swine cysticercosis occurs in high-risk hotspots around carriers where control interventions could be delivered.
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development of a serologic assay to detect taenia solium taeniasis
American Journal of Tropical Medicine and Hygiene, 1999Co-Authors: Patricia P Wilkins, Armando E Gonzalez, Robert H Gilman, Hector H Garcia, J C Allan, Manuela Verastegui, Mariela Acosta, Adam G Eason, Victor C W TsangAbstract:We developed a serologic assay to identify adult Taenia solium tapeworm carriers using excretory/secretory (TSES) antigens collected from in vitro cultured T. solium tapeworms. To identify taeniasis-specific antigens we used an immunoblot assay with serum samples from T. solium tapeworm carriers and cysticercosis patients. Antigens were identified that reacted with antibodies present in serum samples from taeniasis cases and not with those from cysticercosis patients. Using serum samples collected from persons with confirmed T. solium tapeworm infections, the test was determined to be 95% (69 of 73) sensitive. Serum samples (n = 193) from persons with other parasitic infections, including T. saginata tapeworm infections, do not contain cross-reacting antibodies to TSES, indicating that the assay is 100% specific. These data suggest that the immunoblot assay using TSES antigens can be used to identify persons with current or recent T. solium tapeworm infections and provides a new, important tool for epidemiologic purposes, including control and prevention strategies.
Victor C W Tsang - One of the best experts on this subject based on the ideXlab platform.
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clustering of necropsy confirmed porcine cysticercosis surrounding taenia solium tapeworm carriers in peru
American Journal of Tropical Medicine and Hygiene, 2019Co-Authors: Andres G Lescano, Ian W Pray, Armando E Gonzalez, Robert H Gilman, Victor C W Tsang, Ricardo Gamboa, Claudia M GuezalaAbstract:The pork tapeworm, Taenia solium, is among the leading causes of preventable epilepsy in the world and is common in rural areas of developing countries where sanitation is limited and pigs have access to human feces. Prior studies in rural villages of Peru have observed clusters of T. solium cysticercosis among pigs that live near human tapeworm carriers. Such spatial analyses, however, have been limited by incomplete participation and substandard diagnostic tests. In this study, we evaluated the association between necropsy-confirmed cysticercosis in pigs and their distance to T. solium tapeworm carriers in six villages in northern Peru. A total of six (1.4%) tapeworm carriers were detected using copro-antigen enzyme-linked immunosorbent assay and seven of 10 (70%) pigs belonging to the tapeworm carriers were found with viable cyst infection on necropsy. This was significantly greater than the prevalence of viable cyst infection among pigs living 500 m (0.5%) from a tapeworm carrier (P 10 viable cysts, degenerated cyst infection, and serological outcomes. This investigation confirms that porcine cysticercosis clusters strongly around tapeworm carriers in endemic rural regions of northern Peru and supports interventions that target these hotspots.
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taenia solium cysticercosis hotspots surrounding tapeworm carriers clustering on human seroprevalence but not on seizures
PLOS Neglected Tropical Diseases, 2009Co-Authors: Andres G Lescano, Robert H Gilman, Victor C W Tsang, Hector H Garcia, Cesar M Gavidia, Silvia RodriguezAbstract:Background: Neurocysticercosis accounts for 30%–50% of all late-onset epilepsy in endemic countries. We assessed the clustering patterns of Taenia solium human cysticercosis seropositivity and seizures around tapeworm carriers in seven rural communities in Peru. Methodology: The presence of T. solium–specific antibodies was defined as one or more positive bands in the enzymelinked immunoelectrotransfer blot (EITB). Neurocysticercosis-related seizures cases were diagnosed clinically and had positive neuroimaging or EITB. Principal Findings: Eleven tapeworm carriers were identified by stool microscopy. The seroprevalence of human cysticercosis was 24% (196/803). Seroprevalence was 21% .50 m from a carrier and increased to 32% at 1–50 m (p=0.047), and from that distance seroprevalence had another significant increase to 64% at the homes of carriers (p=0.004). Seizure prevalence was 3.0% (25/837) but there were no differences between any pair of distance ranges (p=0.629, Wald test 2 degrees of freedom). Conclusion/Significance: We observed a significant human cysticercosis seroprevalence gradient surrounding current tapeworm carriers, although cysticercosis-related seizures did not cluster around carriers. Due to differences in the timing of the two outcomes, seroprevalence may reflect recent T. solium exposure more accurately than seizure frequency.
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swine cysticercosis hotspots surrounding taenia solium tapeworm carriers
American Journal of Tropical Medicine and Hygiene, 2007Co-Authors: Andres G Lescano, Robert H Gilman, Victor C W Tsang, Claudia M Guezala, Hector H Garcia, Cesar M Gavidia, Silvia Rodriguez, Lawrence H MoultonAbstract:We estimated the Taenia solium swine cysticercosis risk gradient surrounding tapeworm carriers in seven rural communities in Peru. At baseline, the prevalences of taeniasis by microscopy and swine cysticercosis by serology were 1.2% (11 of 898) and 30.8% (280 of 908), respectively. The four-month cumulative seroincidence was 9.8% (30 of 307). The unadjusted swine seroprevalence and seroincidence rates increased exponentially by 12.0% (95% confidence [CI] = 9.7-14.3%) and 32.8% (95% CI = 25.0-41.0%), respectively when distance to carriers decreased by half. Swine seroprevalence was 18.4% at > 500 meters from a carrier, 36.5% between 51 and 500 meters, and 68.9% within 50 meters (P < 0.001). Swine seroincidence also displayed a strong gradient near tapeworm carriers (3.8%, 12.2%, and 44.0%; P < 0.001). Within 50 meters, swine seroprevalence appeared unaffected if the owners harbored tapeworms, although pigs owned by a tapeworm carrier had a four times higher seroincidence compared with other pigs (P = 0.005). In rural areas, swine cysticercosis occurs in high-risk hotspots around carriers where control interventions could be delivered.
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development of a serologic assay to detect taenia solium taeniasis
American Journal of Tropical Medicine and Hygiene, 1999Co-Authors: Patricia P Wilkins, Armando E Gonzalez, Robert H Gilman, Hector H Garcia, J C Allan, Manuela Verastegui, Mariela Acosta, Adam G Eason, Victor C W TsangAbstract:We developed a serologic assay to identify adult Taenia solium tapeworm carriers using excretory/secretory (TSES) antigens collected from in vitro cultured T. solium tapeworms. To identify taeniasis-specific antigens we used an immunoblot assay with serum samples from T. solium tapeworm carriers and cysticercosis patients. Antigens were identified that reacted with antibodies present in serum samples from taeniasis cases and not with those from cysticercosis patients. Using serum samples collected from persons with confirmed T. solium tapeworm infections, the test was determined to be 95% (69 of 73) sensitive. Serum samples (n = 193) from persons with other parasitic infections, including T. saginata tapeworm infections, do not contain cross-reacting antibodies to TSES, indicating that the assay is 100% specific. These data suggest that the immunoblot assay using TSES antigens can be used to identify persons with current or recent T. solium tapeworm infections and provides a new, important tool for epidemiologic purposes, including control and prevention strategies.
