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Minani S, Devleesschauwer B, Gasogo A, Ntirandekura JB, Gabriël S, Dorny P, Trevisan C. Assessing the burden of Taenia solium cysticercosis in Burundi, 2020. BMC Infect Dis 2022; 22:851. [PMCID: PMC9661784 DOI: 10.1186/s12879-022-07849-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 11/07/2022] [Indexed: 11/16/2022] Open
Abstract
Abstract
Background
Taenia solium cysticercosis is a zoonotic disease that is endemic in many low- and middle-income countries where risk factors for disease transmission are present. The economic impact of cysticercosis on public health and on the pig production sector is not well known in many of those countries, including Burundi. This study aimed at estimating the burden of T. solium cysticercosis in Burundi including data on humans and pigs.
Methods
Epidemiological and economic data were collected from literature up to July 30, 2021 and governmental and non-governmental agencies. Direct and indirect costs for neurocysticercosis (NCC)-associated epilepsy and losses due to porcine cysticercosis were estimated to assess the economic burden, while the health burden was estimated using zoonotic disability-adjusted life years (zDALYs). Different probability distributions (Uniform, Beta, Dirichlet and Gamma) were applied depending on the type of epidemiological parameter. Monte Carlo simulations and 100,000 iterations were used to calculate the 95% uncertainty interval (UI) for each parameter and perform sensitivity analyses.
Results
In Burundi, 4.26 million USD (95% UI, 1,858,308–8,190,951) were estimated as economic impact due to T. solium cysticercosis in humans and pigs, of which 40.2% (95% UI, 10.3–75.1) of the total costs were due to NCC-associated epilepsy and 59.8% (95% UI, 24.9–89.7) of the losses due to porcine cysticercosis. The cost per NCC-associated epilepsy case was 72 USD (95% UI, 25–168), representing 30.8% of the GDP per capita in 2020. The probable incident cases and deaths for NCC-associated epilepsy were 9065 (95% UI, 2370–16,716) and 61 (95% UI, 16–114), respectively. More than 2 zDALYs (95% UI, 1.1–3.4) per thousand person-years was estimated, of which an average of 1.3 DALYs [0;0] (95% UI, 0.3–2.6) was due to NCC- associated epilepsy and 0.8 animal loss equivalents (ALEs) (95% UI, 0.3–1.5) due to porcine cysticercosis.
Conclusions
This study provides evidence of a significant burden of T. solium cysticercosis for Burundi’s population. We urge policy makers to use these evidence-based results and put T. solium cysticercosis on the public health agenda of the country. This study recommends urgent action to find solutions for integrated control strategies for T. solium cysticercosis in Burundi.
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Dixon MA, Winskill P, Harrison WE, Basáñez MG. Taenia solium taeniasis/cysticercosis: From parasite biology and immunology to diagnosis and control. ADVANCES IN PARASITOLOGY 2021; 112:133-217. [PMID: 34024358 DOI: 10.1016/bs.apar.2021.03.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
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.
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Affiliation(s)
- Matthew A Dixon
- London Centre for Neglected Tropical Disease Research (LCNTDR), Department of Infectious Disease Epidemiology, Faculty of Medicine, School of Public Health, Imperial College London, London, United Kingdom; MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Faculty of Medicine, School of Public Health, Imperial College London, London, United Kingdom; Schistosomiasis Control Initiative Foundation (SCI Foundation), London, United Kingdom
| | - Peter Winskill
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Faculty of Medicine, School of Public Health, Imperial College London, London, United Kingdom
| | - Wendy E Harrison
- Schistosomiasis Control Initiative Foundation (SCI Foundation), London, United Kingdom
| | - Maria-Gloria Basáñez
- London Centre for Neglected Tropical Disease Research (LCNTDR), Department of Infectious Disease Epidemiology, Faculty of Medicine, School of Public Health, Imperial College London, London, United Kingdom; MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Faculty of Medicine, School of Public Health, Imperial College London, London, United Kingdom.
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Ngowi HA, Winkler AS, Braae UC, Mdegela RH, Mkupasi EM, Kabululu ML, Lekule FP, Johansen MV. Taenia solium taeniosis and cysticercosis literature in Tanzania provides research evidence justification for control: A systematic scoping review. PLoS One 2019; 14:e0217420. [PMID: 31166983 PMCID: PMC6550401 DOI: 10.1371/journal.pone.0217420] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Accepted: 05/11/2019] [Indexed: 11/19/2022] Open
Abstract
Background Despite Taenia solium taeniosis/cysticercosis (TSTC) having been put high on the global agenda of neglected tropical diseases (NTDs), which over the last years has received a lot of attention, there has been no control programmes in place in sub-Saharan Africa, a highly endemic region. This could be attributed to lack of awareness of many stakeholders on the burden and impact of T. solium. This information is essential in guiding TSTC policies, practices and research agendas as well as encouraging cross-sectoral collaboration in the control of this important zoonotic parasite using a One Health approach. National elimination of the parasite is the foundation for global eradication. This will require that substantial country-level information is provided to all key stakeholders. We have mapped out TSTC research evidence in Tanzania to inform on disease burden and potential for integrated control measures. Methodology/Principal findings A scoping review of all TSTC studies undertaken in Tanzania and published up to December 2018 was conducted. The articles were searched from PUBMED, AJOL, Google Scholar and Google in general. Fifty-one (51) articles met the inclusion criteria and were reviewed. Prevalence of taeniosis of 2.3% - 5.2% was estimated based on copro-antigen ELISA while human cysticercosis of >16% was estimated based on serum antigen ELISA (Ag-ELISA) or IgG Western Blot. Neurocysticercosis (NCC) contributed significantly to epilepsy in adults. Farm prevalence of porcine cysticercosis were 6.0% - 17.4% (lingual examination) and 1.5% - 33.3% (Ag-ELISA). Slaughter-slab prevalence were 0% - 18.2% (routine meat inspection). Lacking latrines, watering pigs with river or pond water, and feeding pigs with potato peels were associated with porcine cysticercosis prevalence. Washing hands by dipping method increased the risk of human cysticercosis. In 2012, the number of DALYs/1000 person-years for NCC-associated epilepsy was 0.7 (95% UI, 0.2–1.6), around 5 million USD (95% UI, 797,535–16,933,477) were spent due to NCC-associated epilepsy and nearly 3 million USD (95% UI, 1,095,960–5,366,038) were potentially lost due to porcine cysticercosis. Three rounds of annual treatment of school-age children with praziquantel significantly reduced prevalence of taeniosis and porcine cysticercosis. Health education was efficacious in improving knowledge and attitudes favourable for control of TSTC while a single dose of oxfendazole 30 mg/kg body weight was efficacious in eliminating T. solium cysticerci from pig musculature. Conclusions/Significance The observed high burden of TSTC and the significant contribution of NCC to epilepsy in Tanzania warrant urgent interventions. Evaluation of best control options should make use of disease transmission dynamics models such as cystiSim, taking into account findings from the field based intervention studies. In addition, locally adapted management guidelines for people suffering from NCC are urgently needed.
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Affiliation(s)
- Helena Aminiel Ngowi
- Department of Veterinary Medicine and Public Health, Sokoine University of Agriculture, Morogoro, Tanzania
- * E-mail:
| | - Andrea Sylvia Winkler
- Center for Global Health, Department of Neurology, Technical University of Munich, Munich, Germany
- Centre for Global Health, Department of Community Medicine and Global Health, Institute of Health and Society, University of Oslo, Oslo, Norway
| | - Uffe Christian Braae
- One Health Center for Zoonoses and Tropical Veterinary Medicine, Ross University School of Veterinary Medicine, Basseterre, Saint Kitts and Nevis
- Department of Infectious Disease Epidemiology and Prevention, Statens Serum Institut, Copenhagen, Denmark
| | | | - Ernatus Martin Mkupasi
- Department of Veterinary Medicine and Public Health, Sokoine University of Agriculture, Morogoro, Tanzania
| | | | - Faustin Peter Lekule
- Department of Animal Science and Production, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Maria Vang Johansen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Overview of Taenia solium cysticercosis in West Africa. Acta Trop 2019; 190:329-338. [PMID: 30529447 DOI: 10.1016/j.actatropica.2018.12.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 12/06/2018] [Accepted: 12/06/2018] [Indexed: 12/15/2022]
Abstract
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.
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Alroy KA, Arroyo G, Gilman RH, Gonzales-Gustavson E, Gallegos L, Gavidia CM, Verastegui M, Rodriguez S, Lopez T, Gomez-Puerta LA, Alroy J, Garcia HH, Gonzalez AE, For The Cysticercosis Working Group In Peru. Carotid Taenia solium Oncosphere Infection: A Novel Porcine Neurocysticercosis Model. Am J Trop Med Hyg 2018; 99:380-387. [PMID: 29893202 DOI: 10.4269/ajtmh.17-0912] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Neurocysticercosis (NCC), the infection of the human central nervous system (CNS) with larval cysts of Taenia solium causes widespread neurological morbidity. Animal models are crucial for studying the pathophysiology and treatment of NCC. Some drawbacks of current NCC models include differences in the pathogenesis of the model and wild-type parasite, low rates of infection efficiency and lack of reproducibility. We describe a novel porcine model that recreates infection in the CNS with high efficiency. Activated oncospheres, either in a high (45,000-50,000) or low (10,000) dose were inoculated in the common carotid artery of 12 pigs by ultrasound-guided catheterization. Following oncosphere injection, either a high (30 mL) or low (1-3 mL) volume of saline flush was also administered. Cyst burden in the CNS was evaluated independently according to oncosphere dose and flush volume. Neurocysticercosis was achieved in 8/12 (66.7%) pigs. Cyst burden in the CNS of pigs was higher in the high versus the low oncosphere dose category (median: 4.5; interquartile ranges [IQR]: 1-8 and median: 1; IQR: 0-4, respectively) and in the high versus the low flush volume category (median 5.5; IQR: 1-8 and median: 1; IQR: 0-2, respectively), although not statistically different. All cysts in the CNS were viable, whereas both viable and degenerated cysts were found in the musculature. Carotid injection of activated oncospheres in pigs is effective in reproducing NCC. Oncosphere entry into the CNS by way of vasculature mimics wild-type infection, and provides a useful alternative for future investigations on the pathogenesis and antiparasitic treatment of NCC.
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Affiliation(s)
- Karen A Alroy
- Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
| | - Gianfranco Arroyo
- School of Public Health and Management, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Robert H Gilman
- Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
| | | | - Linda Gallegos
- School of Veterinary Medicine, Universidad Nacional Mayor de San Marcos, Lima, Peru
| | - Cesar M Gavidia
- School of Veterinary Medicine, Universidad Nacional Mayor de San Marcos, Lima, Peru
| | - Manuela Verastegui
- Departments of Pathology, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Silvia Rodriguez
- Microbiology of the School of Science, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Teresa Lopez
- School of Veterinary Medicine, Universidad Nacional Mayor de San Marcos, Lima, Peru
| | - Luis A Gomez-Puerta
- School of Veterinary Medicine, Universidad Nacional Mayor de San Marcos, Lima, Peru
| | - Joseph Alroy
- School of Medicine, Tufts University, Boston, Massachusetts
| | - Hector H Garcia
- Microbiology of the School of Science, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Armando E Gonzalez
- Microbiology of the School of Science, Universidad Peruana Cayetano Heredia, Lima, Peru
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Cangalaya C, Bustos JA, Calcina J, Vargas-Calla A, Mamani J, Suarez D, Arroyo G, Gonzalez AE, Chacaltana J, Guerra-Giraldez C, Mahanty S, Nash TE, García HH. Radiological evolution of porcine neurocysticercosis after combined antiparasitic treatment with praziquantel and albendazole. PLoS Negl Trop Dis 2017; 11:e0005624. [PMID: 28575043 PMCID: PMC5470720 DOI: 10.1371/journal.pntd.0005624] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 06/14/2017] [Accepted: 05/04/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The onset of anthelmintic treatment of neurocysticercosis (NCC) provokes an acute immune response of the host, which in human cases is associated with exacerbation of neurological symptoms. This inflammation can occur at the first days of therapy. So, changes in the brain cysts appearance may be detected by medical imaging. We evaluated radiological changes in the appearance of brain cysts (enhancement and size) on days two and five after the onset of antiparasitic treatment using naturally infected pigs as a model for human NCC. METHODS AND RESULTS Contrast T1-weighted magnetic resonance imaging with gadolinium was performed before and after antiparasitic treatment. Eight NCC-infected pigs were treated with praziquantel plus albendazole and euthanized two (n = 4) and five (n = 4) days after treatment; another group of four infected pigs served as untreated controls. For each lesion, gadolinium enhancement intensity (GEI) and cyst volume were measured at baseline and after antiparasitic treatment. Volume and GEI quantification ratios (post/pre-treatment measures) were used to appraise the effect of treatment. Cysts from untreated pigs showed little variations between their basal and post treatment measures. At days 2 and 5 there were significant increases in GEI ratio compared with the untreated group (1.32 and 1.47 vs 1.01, p = 0.021 and p = 0.021). Cyst volume ratios were significantly lower at days 2 and 5 compared with the untreated group (0.60 and 0.22 vs 0.95, p = 0.04 and p = 0.02). Cysts with lower cyst volume ratios showed more marked post-treatment inflammation, loss of vesicular fluid and cyst wall wrinkling. CONCLUSION/SIGNIFICANCE A significant and drastic reduction of cyst size and increased pericystic enhancement occur in the initial days after antiparasitic treatment as an effect of acute perilesional immune response. These significant changes showed that early anthelmintic efficacy (day two) can be detected using magnetic resonance imaging.
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Affiliation(s)
- Carla Cangalaya
- Laboratorio de Inmunopatología en Neurocisticercosis, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
- Facultad de Medicina Humana, Universidad Nacional Mayor de San Marcos, Lima, Peru
- * E-mail:
| | - Javier A. Bustos
- Unidad de Cisticercosis, Instituto Nacional de Ciencias Neurológicas, Lima, Peru
| | - Juan Calcina
- Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Lima, Peru
| | - Ana Vargas-Calla
- Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Lima, Peru
| | - Javier Mamani
- Facultad de Medicina Veterinaria y Zootecnia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Diego Suarez
- Facultad de Medicina, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Gianfranco Arroyo
- Unidad de Cisticercosis, Instituto Nacional de Ciencias Neurológicas, Lima, Peru
| | - Armando E. Gonzalez
- Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Lima, Peru
| | - Juan Chacaltana
- Departamento de Diagnóstico por imágenes, Instituto Nacional de Ciencias Neurológicas, Lima, Peru
| | - Cristina Guerra-Giraldez
- Laboratorio de Inmunopatología en Neurocisticercosis, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
- Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Siddhartha Mahanty
- Laboratorio de Inmunopatología en Neurocisticercosis, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Theodore E. Nash
- Laboratorio de Inmunopatología en Neurocisticercosis, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Héctor H. García
- Unidad de Cisticercosis, Instituto Nacional de Ciencias Neurológicas, Lima, Peru
- Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
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Trevisan C, Johansen MV, Mkupasi EM, Ngowi HA, Forkman B. Disease behaviours of sows naturally infected with Taenia solium in Tanzania. Vet Parasitol 2017; 235:69-74. [PMID: 28215871 PMCID: PMC5331889 DOI: 10.1016/j.vetpar.2017.01.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 12/14/2016] [Accepted: 01/11/2017] [Indexed: 10/26/2022]
Abstract
Neurocysticercosis (NCC) is a disease caused by the zoonotic parasite Taenia solium lodging in the central nervous system. Both humans and pigs can get NCC. The impact of the disease in pigs has so far been little explored. The aim of this study was to describe the effect of NCC on social and feeding behaviours as well as the pattern of activity as indicators of reduced welfare in naturally infected sows. In total 13 T. solium naturally infected and 15 non-infected control sows were videotaped for 2 consecutive weeks using close circuit television cameras at research facilities at Sokoine University of Agriculture, Morogoro, Tanzania. Videos were analysed at the beginning, in the middle and at the end of the 2 week recording period. For each time point, videos were analysed during feeding, while the enrichment was provided, and by recording every half an hour the sows' behaviours performed over the course of a whole day. Sows with NCC spent significantly less time at the feeding trough, especially during the second half of the feeding period. Infected sows were also more passive e.g. lying and standing still significantly more during a whole day period and showed social isolation compared to non-infected control sows by performing behaviours more distant to their nearest neighbour. Results of this study indicated that NCC changed the behaviour of infected sows. The behavioural changes are indicative of decreased welfare. Efforts to reinforce the animal welfare aspect are needed as this has so far been neglected.
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Affiliation(s)
- Chiara Trevisan
- Department of Veterinary and Animal Sciences, University of Copenhagen, Dyrlægevej 100, 1870 Frederiksberg C, Denmark.
| | - Maria Vang Johansen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Dyrlægevej 100, 1870 Frederiksberg C, Denmark.
| | - Ernatus Martin Mkupasi
- Department of Veterinary Medicine and Public Health, Sokoine University of Agriculture, P.O. Box 3021, Morogoro, Tanzania.
| | - Helena Aminel Ngowi
- Department of Veterinary Medicine and Public Health, Sokoine University of Agriculture, P.O. Box 3021, Morogoro, Tanzania.
| | - Björn Forkman
- Department of Veterinary and Animal Sciences, University of Copenhagen, Grønnegårdsvej 8, 1870 Frederiksberg C, Denmark.
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Trevisan C, Devleesschauwer B, Schmidt V, Winkler AS, Harrison W, Johansen MV. The societal cost of Taenia solium cysticercosis in Tanzania. Acta Trop 2017; 165:141-154. [PMID: 26756713 DOI: 10.1016/j.actatropica.2015.12.021] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 12/11/2015] [Accepted: 12/29/2015] [Indexed: 10/22/2022]
Abstract
Taenia solium is a zoonotic parasite prevalent in many low income countries throughout Latin America, Asia and sub-Saharan Africa, including Tanzania. The parasite is recognized as a public health threat; however the burden it poses on populations of Tanzania is unknown. The aim of this study was to estimate the societal cost of T. solium cysticercosis in Tanzania, by assessing both the health and economic burden. The societal cost of T. solium cysticercosis was assessed in humans and pigs based on data obtained by a systematic review. Experts' opinion was sought in cases where data were not retrievable. The health burden was assessed in terms of annual number of neurocysticercosis (NCC) associated epilepsy incident cases, deaths and disability-adjusted life years (DALYs), while the economic burden was assessed in terms of direct and indirect costs imposed by NCC-associated epilepsy and potential losses due to porcine cysticercosis. Based on data retrieved from the systematic review and burden assessments, T. solium cysticercosis contributed to a significant societal cost for the population. The annual number of NCC-associated epilepsy incident cases and deaths were 17,853 (95% Uncertainty Interval (UI), 5666-36,227) and 212 (95% UI, 37-612), respectively. More than 11% (95% UI, 6.3-17) of the pig population was infected with the parasite when using tongue examination as diagnostic method. For the year 2012 the number of DALYs per thousand person-years for NCC-associated epilepsy was 0.7 (95% UI, 0.2-1.6). Around 5 million USD (95% UI, 797,535-16,933,477) were spent due to NCC-associated epilepsy and nearly 3 million USD (95% UI, 1,095,960-5,366,038) were potentially lost due to porcine cysticercosis. Our results show that T. solium imposes a serious public health, agricultural and economic threat for Tanzania. We urge that a One Health approach, which involves the joint collaboration and effort of veterinarians, medical doctors, agricultural extension officers, researchers and relevant governmental agencies, is taken to find sustainable solutions for prevention, control and elimination of T. solium.
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Perilesional Inflammation in Neurocysticercosis - Relationship Between Contrast-Enhanced Magnetic Resonance Imaging, Evans Blue Staining and Histopathology in the Pig Model. PLoS Negl Trop Dis 2016; 10:e0004869. [PMID: 27459388 PMCID: PMC4961384 DOI: 10.1371/journal.pntd.0004869] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 06/30/2016] [Indexed: 11/19/2022] Open
Abstract
Background Disease manifestations in neurocysticercosis (NCC) are frequently due to inflammation of degenerating Taenia solium brain cysts. Exacerbated inflammation post anthelmintic treatment is associated with leakage of the blood brain barrier (BBB) using Evans blue (EB) staining. How well EB extravasation into the brain correlates with magnetic resonance imaging (MRI) using gadolinium (Gd) enhancement as a contrast agent and pericystic inflammation was analyzed in pigs harboring brain cysts of Taenia solium. Methodology/Principal Findings Three groups of 4 naturally infected pigs were assessed. The first and second groups were treated with both praziquantel plus albendazole and sacrificed two and five days post treatment, respectively. A third untreated group remained untreated. Pigs were injected with EB two hours prior to evaluation by Gd-enhanced T1-MRI, and euthanized. The EB staining for each cyst capsule was scored (EB grades were 0: 0%; 1: up to 50%; 2: over 50% but less than 100%; 3: 100%). Similarly, the Gd enhancement around each cyst was qualitatively and quantitatively scored from the MRI. The extent of pericystic inflammation on histology was scored in increasing severity as IS1, IS2, IS3 and IS4. Grade 3 EB staining and enhancement was only seen in treated capsules. Also, treated groups had higher Gd intensity than the untreated group. Grades of enhancement correlated significantly with Gd enhancement intensity. EB staining was correlated with Gd enhancement intensity and with IS4 in the treated groups. These correlations were stronger in internally located cysts compared to superficial cysts in treated groups. Significance EB staining and Gd enhancement strongly correlate. The intensity of enhancement determined by MRI is a good indication of the degree of inflammation. Similarly, EB staining highly correlates with the degree of inflammation and may be applied to study inflammation in the pig model of NCC. Neurocysticercosis (NCC) is a frequent parasitic infection of the human brain in developing countries. The symptomatology of human NCC after antiparasitic treatment is generally related to inflammation. The presence and degree of enhancement after intravascular injection of the contrast agent gadolinium in magnetic resonance imaging (MRI) is commonly considered an evidence of blood brain barrier (BBB) leakage. Experimentally, the presence and degree of extravasation of Evans blue (EB) after intravascular injection into the tissues of the brain is a direct measure of blood brain barrier leakage. The BBB leakage of gadolinium in neurocysticercosis is commonly used as an indirect measure of inflammation but has never been experimentally proven. Here we evaluated the relationship between contrast T1-MRI, EB staining and histology findings in naturally infected pigs. There was a strong correlation between EB staining, contrast MRI and histopathology findings after antiparasitic treatment. This correlation was stronger when cysts were internally located in the brain than in superficial cysts partly located in the subarachnoid space (meninges). Contrast-enhanced MRI is a non invasive tool used in diagnosis and follow up of NCC patients. This study shows that the use of EB staining allows for the same conclusions as when using MRI post-treatment, and that both techniques correlate with histopathology findings. These results support the use of EB staining to study NCC using the porcine model as well as validate MRI enhancement to assess brain inflammation in patients.
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Severe seizures in pigs naturally infected with Taenia solium in Tanzania. Vet Parasitol 2016; 220:67-71. [PMID: 26995723 PMCID: PMC4819911 DOI: 10.1016/j.vetpar.2016.02.025] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Revised: 01/27/2016] [Accepted: 02/25/2016] [Indexed: 11/28/2022]
Abstract
Pigs with neurocysticercosis can develop clinical signs and suffer from seizures. Autonomic signs were chewing motions with foamy salivation and ear stiffening. Motor signs included tonic muscle contractions and tremor. Stereotypic walking in circles was observed on several occasions.
Neurocysticercosis (NCC) caused by Taenia solium is a serious neurological disease. In humans neurological symptoms have been thoroughly studied and documented, however, there is limited information on clinical signs in pigs infected with T. solium cysticerci. Among the scientific community, it is in fact believed that pigs with NCC rarely show neurological signs. The aim of this study was to describe clinical manifestations associated with NCC in pigs and correlate the manifestations to the number and distribution of cysticerci in brains of naturally infected pigs in Tanzania. Sixteen infected and 15 non-infected control pigs were observed for 14 days during daylight hours, and subsequently videotaped for another 14 consecutive days using close circuit television cameras. All occurrences of abnormal behaviour (trembling, twitching, mouth and ear paralysis, ataxia, dribbling, salivating, eye blinking, walking in circles) were recorded. At the end of the recording period, pigs were slaughtered and their brains dissected, cysticerci counted and locations noted. During the recording period, two infected pigs were observed having seizures. Some of the observed autonomic signs during a seizure were chewing motions with foamy salivation and ear stiffening. Motor signs included tonic muscle contractions followed by a sudden diminution in all muscle function leading to collapse of the animal. Stereotypic walking in circles was observed on several occasions. At dissection, both pigs had a high number of brain cysticerci (241 and 247 cysticerci). The two pigs with seizures were also older (36 months) compared to the others (18.3 months, ± 8.2 standard deviation). Results of this study have shown that pigs with NCC can develop clinical signs and suffer from seizures like humans with symptomatic NCC. Results of this study could potentially open up a new experimental pathway to explore the aetiology of neurological symptoms in humans with NCC associated epilepsy.
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Cangalaya C, Zimic M, Marzal M, González AE, Guerra-Giraldez C, Mahanty S, Nash TE, García HH. Inflammation Caused by Praziquantel Treatment Depends on the Location of the Taenia solium Cysticercus in Porcine Neurocysticercosis. PLoS Negl Trop Dis 2015; 9:e0004207. [PMID: 26658257 PMCID: PMC4689503 DOI: 10.1371/journal.pntd.0004207] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 10/12/2015] [Indexed: 12/04/2022] Open
Abstract
Background Neurocysticercosis (NCC), infection of the central nervous system by Taenia solium cysticerci, is a pleomorphic disease. Inflammation around cysticerci is the major cause of disease but is variably present. One factor modulating the inflammatory responses may be the location and characteristics of the brain tissue adjacent to cysticerci. We analyzed and compared the inflammatory responses to cysticerci located in the parenchyma to those in the meninges or cysticerci partially in contact with both the parenchyma and the meninges (corticomeningeal). Methodology/Principal Findings Histological specimens of brain cysticerci (n = 196) from 11 pigs naturally infected with Taenia solium cysticerci were used. Four pigs were sacrificed after 2 days and four after 5 days of a single dose of praziquantel; 3 pigs did not receive treatment. All pigs were intravenously injected with Evans Blue to assess disruption of the blood-brain barrier. The degree of inflammation was estimated by use of a histological score (ISC) based on the extent of the inflammation in the pericystic areas as assessed in an image composed of several photomicrographs taken at 40X amplification. Parenchymal cysticerci provoked a significantly greater level of pericystic inflammation (higher ISC) after antiparasitic treatment compared to meningeal and corticomeningeal cysticerci. ISC of meningeal cysticerci was not significantly affected by treatment. In corticomeningeal cysticerci, the increase in ISC score was correlated to the extent of the cysticercus adjacent to the brain parenchyma. Disruption of the blood-brain barrier was associated with treatment only in parenchymal tissue. Significance Inflammatory response to cysticerci located in the meninges was significantly decreased compared to parenchymal cysticerci. The suboptimal inflammatory response to cysticidal drugs may be the reason subarachnoid NCC is generally refractory to treatment compared to parenchymal NCC. The cystic larvae of the pork tapeworm Taenia solium may affect the human brain causing neurocysticercosis (NCC), a very frequent cause of neurological symptoms in developing countries. The clinical expression and response to treatment of human NCC are related to the location of cysticerci inside (intraparenchymal) or outside the brain parenchyma (extraparenchymal NCC). We used a naturally infected pig model to assess the characteristics of inflammation around brain cysticerci of parenchymal, meningeal and mixed locations. There were no major differences in inflammation without treatment. After antiparasitic treatment with praziquantel, inflammation around parenchymal brain cysticerci increased in comparison to meningeal located cysticerci. Cysticerci partially surrounded by both brain parenchyma and meninges showed increased inflammation in relation to the extent of the cysticercus in the brain parenchyma. The location of cysticerci within the brain is a factor that determines the extent and degree of the immune response following anticysticidal treatment. Similar changes may occur in treated human infections. Our work could contribute to explain the differences in response to antiparasitic treatment in different forms of human neurocysticercosis.
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Affiliation(s)
- Carla Cangalaya
- Laboratorio de Inmunopatología en Neurocisticercosis, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
- * E-mail:
| | - Mirko Zimic
- Laboratorio de Bioinformática y Biología Molecular, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
- Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Miguel Marzal
- Laboratorio de Inmunopatología en Neurocisticercosis, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Armando E. González
- Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Lima, Perú
| | - Cristina Guerra-Giraldez
- Laboratorio de Inmunopatología en Neurocisticercosis, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
- Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Siddhartha Mahanty
- Laboratorio de Inmunopatología en Neurocisticercosis, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Theodore E. Nash
- Laboratorio de Inmunopatología en Neurocisticercosis, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Hector H. García
- Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
- Unidad de Cisticercosis, Instituto Nacional de Ciencias Neurológicas, Lima, Perú
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Braae UC, Saarnak CFL, Mukaratirwa S, Devleesschauwer B, Magnussen P, Johansen MV. Taenia solium taeniosis/cysticercosis and the co-distribution with schistosomiasis in Africa. Parasit Vectors 2015; 8:323. [PMID: 26065414 PMCID: PMC4465723 DOI: 10.1186/s13071-015-0938-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 06/05/2015] [Indexed: 12/03/2022] Open
Abstract
Background This study aimed to map the distribution of Taenia solium taeniosis/cysticercosis and the co-distribution with schistosomiasis in Africa. These two major neglected tropical diseases are presumed to be widely distributed in Africa, but currently the level of co-distribution is unclear. Methods A literature search on T. solium taeniosis/cysticercosis was performed to compile all known studies on the presence of T. solium and apparent prevalence of taeniosis and porcine cysticercosis in Africa. Studies were geo-referenced using an online gazetteer. A Bayesian framework was used to combine the epidemiological data on the apparent prevalence with external information on test characteristics to estimate informed district-level prevalence of taeniosis and porcine cysticercosis. Districts with T. solium taeniosis/cysticercosis presence were cross-referenced with the Global Neglected Tropical Diseases Database for schistosomiasis presence. Results The search strategies identified 141 reports of T. solium in Africa from 1985 to 2014 from a total of 476 districts in 29 countries, 20 with porcine cysticercosis, 22 with human cysticercosis, and 16 with taeniosis, in addition to 2 countries identified from OIE reports. All 31 countries were considered, on national scale, to have co-distribution with schistosomiasis. Presence of both parasites was confirmed in 124 districts in 17 countries. The informed prevalence of taeniosis and porcine cysticercosis were estimated for 14 and 41 districts in 10 and 13 countries, respectively. Conclusions With the paucity of data, T. solium infection is grossly under-reported and expected to be more widespread than this study suggests. In areas where co-distribution occurs there is a need for increased emphasis on evaluation of integrated intervention approaches for these two helminth infections and allocation of resources for evaluating the extent of adverse effects caused by mass drug administration. Electronic supplementary material The online version of this article (doi:10.1186/s13071-015-0938-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Uffe Christian Braae
- Department of Veterinary Disease Biology, Section for Parasitology and Aquatic Diseases, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870, Frederiksberg, Denmark.
| | - Christopher F L Saarnak
- Department of Veterinary Disease Biology, Section for Parasitology and Aquatic Diseases, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870, Frederiksberg, Denmark.
| | - Samson Mukaratirwa
- School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa.
| | - Brecht Devleesschauwer
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, 9820, Merelbeke, Belgium. .,Institute of Health and Society (IRSS), Université catholique de Louvain, 1200, Brussels, Belgium.
| | - Pascal Magnussen
- Department of Veterinary Disease Biology, Section for Parasitology and Aquatic Diseases, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870, Frederiksberg, Denmark. .,Centre for Medical Parasitology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1353, Copenhagen, Denmark.
| | - Maria Vang Johansen
- Department of Veterinary Disease Biology, Section for Parasitology and Aquatic Diseases, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870, Frederiksberg, Denmark.
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