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Kwoba E, Oduori DO, Lambertini E, Thomas LF, Grace D, Mutua F. Food safety interventions in low- and middle-income countries in Asia: A systematic review. Zoonoses Public Health 2023; 70:187-200. [PMID: 36718488 DOI: 10.1111/zph.13028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 12/07/2022] [Accepted: 01/12/2023] [Indexed: 02/01/2023]
Abstract
Effective and sustainable interventions are necessary for long-term improvement of food safety. This review provides a summary of food safety interventions evaluated in selected low- and middle-income countries in Asia between 2000 and 2020. A systematic screening of published articles from PubMed and CabDirect databases was carried out with the aid of Rayyan QCRI software. A total of 25 studies were considered in the review. A 'before and after' study design was the most frequently used design (64%), while five studies (20%) used a randomized control trial (RCT) design. Interventions applied focused on training to improve knowledge, attitudes, and practices (KAP) towards safe food (60%) or on specific technologies (40%). Nine of the 25 studies were specific on the value chain considered: cattle (1), poultry (1), pigs (4) and fish value chains (3). Except for one study, all interventions reported some level of success; 17 were rated as having a high level of success, defined differently across studies. However, there is a clear evidence gap for the efficacy and cost-effectiveness of food safety interventions in market settings, both consumer- and vendor-facing. A rigorous and standardized assessment of intervention effectiveness and sustainability is recommended, to not only identify areas of improvement, but also to ensure scaling of interventions with demonstrated evidence of success and sustainability.
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Affiliation(s)
- Emmah Kwoba
- International Livestock Research Institute, Nairobi, Kenya
| | - David Obiero Oduori
- International Livestock Research Institute, Nairobi, Kenya.,Maasai Mara University, Narok, Kenya
| | | | - Lian Francesca Thomas
- International Livestock Research Institute, Nairobi, Kenya.,Institute of Infection Veterinary & Ecological Sciences, University of Liverpool, Leahurst Campus, Neston, UK
| | - Delia Grace
- International Livestock Research Institute, Nairobi, Kenya.,Natural Resources Institute, University of Greenwich, Kent, UK
| | - Florence Mutua
- International Livestock Research Institute, Nairobi, Kenya
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Van Damme I, Pray I, Mwape KE, Trevisan C, Coudenys F, Mubanga C, Mwelwa C, Vaernewyck V, Dorny P, O'Neal SE, Gabriël S. Movements of free-range pigs in rural communities in Zambia: an explorative study towards future ring interventions for the control of Taenia solium. Parasit Vectors 2022; 15:150. [PMID: 35477431 PMCID: PMC9044682 DOI: 10.1186/s13071-022-05264-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/30/2022] [Indexed: 11/13/2022] Open
Abstract
Background Taenia solium typically affects resource-poor communities where pigs are allowed to roam freely, and sanitation and hygiene levels are suboptimal. Sustainable, long-term strategies are urgently needed to control the disease. Geographically targeted interventions, i.e. screening or treatment of taeniosis among people living near infected pigs (defined as ring screening and ring treatment, respectively), have been shown to be effective control options in Peru. However, these results might not be directly generalizable to sub-Saharan African settings. Pig movements play a vital role in the transmission and, consequently, the success of ring interventions against T. solium. The aim of the present study was to explore roaming patterns of pigs in T. solium endemic communities in Zambia as a first step toward evaluating whether ring interventions should be considered as a treatment option in Zambia. Methods In total, 48 free-roaming pigs in two rural neighborhoods in the Eastern Province of Zambia were tracked using a Global Positioning System (GPS) receiver. Tracking took place in April (end of the rainy season) 2019 and October (end of the dry season) 2019. The number of revisitations and the time spent within rings of different radii (50, 100 and 250 m) around the coordinates of each pig owner’s household were calculated for each pig. Results The total tracking time for 43 pigs in the final analysis set ranged between 43 and 94 h. Pigs spent a median of 31% and 13% of the tracked time outside the 50- and 100-m radius, respectively, although large variations were observed between pigs. Overall, 25 pigs (58%) went outside the 250-m ring at least once, and individual excursions lasting up to 16 h were observed. In the dry season, 17 out of 23 pigs went outside the 250-m radius compared to only eight out of 20 pigs in the rainy season (P = 0.014). Conclusions In our study sites in Zambia, the majority of pigs spent most of their time within 50 or 100 m of their owner’s home, and these results are comparable with those on Peruvian pigs. Both radii could therefore be considered reasonable options in future ring interventions. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05264-0.
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Affiliation(s)
- Inge Van Damme
- Laboratory of Foodborne Parasitic Zoonoses, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - Ian Pray
- School of Public Health, Oregon Health & Science University-Portland State University, Portland, USA
| | - Kabemba E Mwape
- Department of Clinical Studies, School of Veterinary Medicine, University of Zambia, Lusaka, Zambia
| | - Chiara Trevisan
- Laboratory of Foodborne Parasitic Zoonoses, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium.,Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Fien Coudenys
- Laboratory of Foodborne Parasitic Zoonoses, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - Chishimba Mubanga
- Department of Clinical Studies, School of Veterinary Medicine, University of Zambia, Lusaka, Zambia
| | - Chembesofu Mwelwa
- Department of Clinical Studies, School of Veterinary Medicine, University of Zambia, Lusaka, Zambia
| | - Victor Vaernewyck
- Laboratory of Foodborne Parasitic Zoonoses, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - Pierre Dorny
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Seth E O'Neal
- School of Public Health, Oregon Health & Science University-Portland State University, Portland, USA.,Center for Global Health-Tumbes, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Sarah Gabriël
- Laboratory of Foodborne Parasitic Zoonoses, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium.
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Evaluation of an Antibody Detecting Point of Care Test for Diagnosis of Taenia solium Cysticercosis in a Zambian Rural Community: A Prospective Diagnostic Accuracy Study. Diagnostics (Basel) 2021; 11:diagnostics11112121. [PMID: 34829468 PMCID: PMC8618153 DOI: 10.3390/diagnostics11112121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 11/02/2021] [Accepted: 11/10/2021] [Indexed: 11/18/2022] Open
Abstract
The lack of cheap, easy-to-use, rapid diagnostic tests has led to the development of several rapid diagnostic tests for cysticercosis. The new prototype two-strip, Taenia solium point of care test (TS POC) detects antibodies against taeniosis (TS POC T) and cysticercosis (TS POC CC). This study evaluated the diagnostic performance of the TS POC CC in the Sinda district in eastern Zambia. A sample of 1254 participants was recruited and tested with the TS POC. Out of the 1249 participants with a valid TS POC result, 177 (14%) tested positive while 1072 (86%) tested negative. All individuals with a positive TS POC and a subset of negative TS POC participants were selected for serum sampling, and were subjected to the recombinant glycoprotein T24H enzyme-linked immunoelectrotransfer blot (rT24H EITB) and the serum B60/158 (serum Ag) enzyme-linked immunosorbent assay (Ag ELISA). Performance characteristics were estimated using a Bayesian approach with probabilistic constraints. Based on 255 complete cases, the estimated sensitivity and specificity of the TS POC CC test were 35% (95% CI: 14–63%) and 87% (95% CI: 83–90%), respectively. The diagnostic performance needs to be improved, possibly by titrating antigen and other reagents’ concentration in the strip to produce a performance similar to existing cysticercosis tests such as the rT24H EITB.
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Mubanga C, Trevisan C, Van Damme I, Schmidt V, Phiri IK, Zulu G, Noh J, Handali S, Mambo R, Chembensofu M, Masuku M, Reynders D, Jansen F, Bottieau E, Magnussen P, Winkler AS, Dorny P, Mwape KE, Gabriel S. Challenges Encountered When Evaluating an Antibody-Detecting Point-of-Care Test for Taeniosis in an Endemic Community in Zambia: A Prospective Diagnostic Accuracy Study. Diagnostics (Basel) 2021; 11:diagnostics11112039. [PMID: 34829386 PMCID: PMC8625551 DOI: 10.3390/diagnostics11112039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 11/01/2021] [Accepted: 11/01/2021] [Indexed: 11/16/2022] Open
Abstract
Taenia solium taeniosis diagnosis is challenging because current tests perform sub-optimally and/or are expensive, require sophisticated equipment, infrastructure and trained manpower, and therefore are not community deployable. A recently-developed, multi-strip, T. solium point-of-care test (TS POC) for simultaneous detection of tapeworm (TS POC T) and cysticercus (TS POC CC) human antibodies was evaluated for diagnostic accuracy on consecutively recruited community participants in Sinda district, Zambia. All participants were tested using the TS POC test. All test-positives and 20% of the test-negative participants were invited to give a blood and stool sample for reference testing. Three different reference tests were used for taeniosis diagnosis: recombinant rES33 enzyme-linked immunoelectrotransfer blot (rES33 EITB), copro PCR and copro Ag ELISA. Bayesian analysis with probabilistic constraints was used to estimate sensitivity and specificity. In total, 1254 participants were tested with the TS POC test, of whom 13 tested positive using the TS POC T. Based on 161 participants with complete data, the estimated sensitivity and specificity for the TS POC T test were 38% (95% CI: 5–93%) and 99% (95% CI: 98–100%), respectively. The challenge of highly variable inter-assay performance is highlighted. We recommend either increasing the sensitivity or redesigning the test.
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Affiliation(s)
- Chishimba Mubanga
- Department of Clinical Studies, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia or (C.M.); (I.K.P.); (G.Z.); (R.M.); (M.C.); (M.M.); (K.E.M.)
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium; (C.T.); (I.V.D.)
| | - Chiara Trevisan
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium; (C.T.); (I.V.D.)
- Department of Biomedical Sciences, Institute of Tropical Medicine, 2000 Antwerp, Belgium; (F.J.); (P.D.)
| | - Inge Van Damme
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium; (C.T.); (I.V.D.)
| | - Veronika Schmidt
- Department of Neurology, Center for Global Health, Faculty of Medicine, Technical University of Munich, 81675 Munich, Germany; (V.S.); (A.S.W.)
- Centre for Global Health, Institute of Health and Society, Faculty of Medicine, University of Oslo, 0450 Oslo, Norway
| | - Isaac K. Phiri
- Department of Clinical Studies, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia or (C.M.); (I.K.P.); (G.Z.); (R.M.); (M.C.); (M.M.); (K.E.M.)
| | - Gideon Zulu
- Department of Clinical Studies, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia or (C.M.); (I.K.P.); (G.Z.); (R.M.); (M.C.); (M.M.); (K.E.M.)
- Eastern Provincial Health Office, Ministry of Health, Chipata 510023, Zambia
| | - John Noh
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA; (J.N.); (S.H.)
| | - Sukwan Handali
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA; (J.N.); (S.H.)
| | - Richard Mambo
- Department of Clinical Studies, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia or (C.M.); (I.K.P.); (G.Z.); (R.M.); (M.C.); (M.M.); (K.E.M.)
- Eastern Provincial Health Office, Ministry of Health, Chipata 510023, Zambia
| | - Mwelwa Chembensofu
- Department of Clinical Studies, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia or (C.M.); (I.K.P.); (G.Z.); (R.M.); (M.C.); (M.M.); (K.E.M.)
| | - Maxwell Masuku
- Department of Clinical Studies, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia or (C.M.); (I.K.P.); (G.Z.); (R.M.); (M.C.); (M.M.); (K.E.M.)
| | - Dries Reynders
- Department of Applied Mathematics, Computer Science and Statistics, Faculty of Sciences, Ghent University, 9000 Ghent, Belgium;
| | - Famke Jansen
- Department of Biomedical Sciences, Institute of Tropical Medicine, 2000 Antwerp, Belgium; (F.J.); (P.D.)
| | - Emmanuel Bottieau
- Department of Clinical Sciences, Institute of Tropical Medicine, 2000 Antwerp, Belgium;
| | - Pascal Magnussen
- Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark;
| | - Andrea S. Winkler
- Department of Neurology, Center for Global Health, Faculty of Medicine, Technical University of Munich, 81675 Munich, Germany; (V.S.); (A.S.W.)
- Centre for Global Health, Institute of Health and Society, Faculty of Medicine, University of Oslo, 0450 Oslo, Norway
| | - Pierre Dorny
- Department of Biomedical Sciences, Institute of Tropical Medicine, 2000 Antwerp, Belgium; (F.J.); (P.D.)
| | - Kabemba E. Mwape
- Department of Clinical Studies, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia or (C.M.); (I.K.P.); (G.Z.); (R.M.); (M.C.); (M.M.); (K.E.M.)
| | - Sarah Gabriel
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium; (C.T.); (I.V.D.)
- Correspondence:
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Van Damme I, Trevisan C, Mwape KE, Schmidt V, Magnussen P, Zulu G, Mubanga C, Stelzle D, Bottieau E, Abatih E, Phiri IK, Johansen MV, Chabala C, Winkler AS, Dorny P, Gabriël S. Trial Design for a Diagnostic Accuracy Study of a Point-of-Care Test for the Detection of Taenia solium Taeniosis and (Neuro)Cysticercosis in Community Settings of Highly Endemic, Resource-Poor Areas in Zambia: Challenges and Rationale. Diagnostics (Basel) 2021; 11:diagnostics11071138. [PMID: 34206654 PMCID: PMC8306489 DOI: 10.3390/diagnostics11071138] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 06/10/2021] [Accepted: 06/19/2021] [Indexed: 11/16/2022] Open
Abstract
Field-applicable, high-quality, and low-cost diagnostic tools are urgently needed for Taenia solium. The aim of this paper is to describe the design, challenges, and rationale for the design of a diagnostic accuracy study in low-resource community settings in Zambia. The trial was designed as a prospective study with a two-stage design to evaluate a new point-of-care test (TS POC) for the detection of taeniosis and (neuro)cysticercosis. Participants within randomly selected households were tested with the TS POC test (index test). Participants who tested TS POC positive for taeniosis and/or cysticercosis and a subset of the negatives were requested to give blood and stool samples for reference testing, and to undergo clinical examination and a cerebral CT scan. The difficulties of conducting a clinical trial in settings with limited research and neuroimaging infrastructure as well as peculiarities specifically related to the disease (low prevalence of taeniosis and the lack of a gold standard) were taken into consideration for the design of this study. The two-stage design increased the efficiency of the study by reducing the number of samples, clinical examinations, and CT scans. Simplified flows and sampling processes were preferred over complex follow-up and randomization systems, aiming to reduce bias and increase the generalizability of the study.
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Affiliation(s)
- Inge Van Damme
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium; (C.T.); (C.M.)
- Correspondence: (I.V.D.); (S.G.)
| | - Chiara Trevisan
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium; (C.T.); (C.M.)
- Department of Biomedical Sciences, Institute of Tropical Medicine, 2000 Antwerp, Belgium;
| | - Kabemba E. Mwape
- Department of Clinical Studies, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia; (K.E.M.); (G.Z.); (I.K.P.)
| | - Veronika Schmidt
- Department of Neurology, Center for Global Health, Klinikum Rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (V.S.); (D.S.); (A.S.W.)
- Centre for Global Health, Institute of Health and Society, Faculty of Medicine, University of Oslo, 0450 Oslo, Norway
| | - Pascal Magnussen
- Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark;
| | - Gideon Zulu
- Department of Clinical Studies, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia; (K.E.M.); (G.Z.); (I.K.P.)
- Ministry of Health, Lusaka 10101, Zambia
| | - Chishimba Mubanga
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium; (C.T.); (C.M.)
- Department of Clinical Studies, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia; (K.E.M.); (G.Z.); (I.K.P.)
| | - Dominik Stelzle
- Department of Neurology, Center for Global Health, Klinikum Rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (V.S.); (D.S.); (A.S.W.)
| | - Emmanuel Bottieau
- Department of Clinical Sciences, Institute of Tropical Medicine, 2000 Antwerp, Belgium;
| | - Emmanuel Abatih
- Department of Applied Mathematics, Computer Sciences and Statistics, Faculty of Sciences, Ghent University, 9000 Ghent, Belgium;
| | - Isaac K. Phiri
- Department of Clinical Studies, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia; (K.E.M.); (G.Z.); (I.K.P.)
| | | | - Chishala Chabala
- Paediatrics and Child Health, Children’s Hospital, University Teaching Hospitals, Lusaka 10101, Zambia;
- Department of Paediatrics and Child Health, School of Medicine, University of Zambia, Lusaka 10101, Zambia
| | - Andrea S. Winkler
- Department of Neurology, Center for Global Health, Klinikum Rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (V.S.); (D.S.); (A.S.W.)
- Centre for Global Health, Institute of Health and Society, Faculty of Medicine, University of Oslo, 0450 Oslo, Norway
| | - Pierre Dorny
- Department of Biomedical Sciences, Institute of Tropical Medicine, 2000 Antwerp, Belgium;
| | - Sarah Gabriël
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium; (C.T.); (C.M.)
- Correspondence: (I.V.D.); (S.G.)
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Ouma E, Dione M, Mtimet N, Lule P, Colston A, Adediran S, Grace D. Demand for Taenia solium Cysticercosis Vaccine: Lessons and Insights From the Pig Production and Trading Nodes of the Uganda Pig Value Chain. Front Vet Sci 2021; 8:611166. [PMID: 33987216 PMCID: PMC8110731 DOI: 10.3389/fvets.2021.611166] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 03/25/2021] [Indexed: 11/13/2022] Open
Abstract
Taenia solium cysticercosis disease remains a key challenge to the pig sector in low- and middle-income countries in sub-Saharan Africa, Latin America and South East Asia, resulting in both economic losses and public health impacts. The World Health Organization has ranked it first on the global scale of foodborne parasites. A One Health approach has been recommended for reduction of infection pressure and eradication in the longer term. A new vaccine TSOL18 (Cysvax™), applied in combination with oxfendazole (Paranthic 10%™), a dewormer drug has been developed and field tested for the control of T. solium cysticercosis, with high potential to break the disease cycle. It is however unclear whether the products can be marketed through a market driven approach, and if smallholder pig farmers would be willing to take up and pay for the vaccine–oxfendazole combination. A choice experiment methodology was used to assess the potential demand and willingness to pay for the vaccine—oxfendazole combination by Ugandan smallholder pig farmers, and demand for vaccinated pigs by pig traders. The results showed that farmers highly valued quality assurance attributes and were not keen on the vaccine if there were no associated returns in the form of premium price for vaccinated pigs during sales. They were willing to pay US$ 2.31 for the vaccine if it resulted in a premium price for vaccinated pigs. Furthermore, they preferred an accompanying vaccine viability detector as part of its quality assurance. The pig traders on the other hand preferred high carcass weight of pigs, potentially achieved by using oxfendazole. The results show that unless the pig market systems pay a premium price for vaccinated pigs, and quality assurance systems guarantee quality vaccine, uptake of the TSOL18 vaccine and oxfendazole by farmers through market mechanisms may be unsuccessful. The current pig marketing system does not reward food safety, the focus is mainly on carcass weight. Alternative delivery mechanisms for the vaccine through a mix of private–public investments needs to be explored, as the benefits of vaccinated pigs are societal and include reduction and elimination of neurocysticercosis in the long run.
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Affiliation(s)
- Emily Ouma
- Policies, Institutions and Livelihood Program, International Livestock Research Institute, Kampala, Uganda
| | - Michel Dione
- Animal and Human Health Program, International Livestock Research Institute, Dakar, Senegal
| | - Nadhem Mtimet
- International Fund for Agricultural Development (IFAD), Cairo, Egypt
| | - Peter Lule
- Policies, Institutions and Livelihood Program, International Livestock Research Institute, Kampala, Uganda
| | - Angie Colston
- Global Alliance for Livestock Veterinary Medicines, Nairobi, Kenya
| | - Samuel Adediran
- Global Alliance for Livestock Veterinary Medicines, Nairobi, Kenya.,Impact at Scale Program, International Livestock Research Institute, Addis Ababa, Ethiopia
| | - Delia Grace
- Animal and Human Health Program, International Livestock Research Institute, Nairobi, Kenya.,Food Safety Systems, Natural Resources Institute, University of Greenwich, Kent, United Kingdom
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Ramiandrasoa NS, Ravoniarimbinina P, Solofoniaina AR, Andrianjafy Rakotomanga IP, Andrianarisoa SH, Molia S, Labouche AM, Fahrion AS, Donadeu M, Abela-Ridder B, Rajaonatahina D. Impact of a 3-year mass drug administration pilot project for taeniasis control in Madagascar. PLoS Negl Trop Dis 2020; 14:e0008653. [PMID: 32946447 PMCID: PMC7500903 DOI: 10.1371/journal.pntd.0008653] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 07/28/2020] [Indexed: 01/15/2023] Open
Abstract
Taenia solium is endemic in Madagascar and presents a significant burden on the population and the health system. The parasite cycles through humans who host the adult tapeworm, and pigs that host the larval stages. Accidental infection of humans may occur with the larval stages which encyst in the nervous central system causing neurocysticercosis, a major cause of seizure disorders and a public health problem. One of the interventions to facilitate the control of the disease is mass drug administration (MDA) of the human population with taeniacide. Here we describe a pilot project conducted in Antanifotsy district of Madagascar from 2015 to 2017 where three annual rounds of MDA (praziquantel, 10mg/Kg) were undertaken in 52 villages. Changes in the prevalence of taeniasis were assessed before, during and after the treatments. A total of 221,308 treatments were given to all eligible people above 5 years of age representing a 95% coverage of the targeted population. No major adverse effects were notified related to the implementation of the MDA. The prevalence of taeniasis was measured using Kato-Katz and copro-antigen techniques. Analyses undertaken combining the results of the Kato-Katz with copro-antigen, or using the Kato-Katz results alone, showed that there was a significant reduction in taeniasis 4 months after the last MDA, but 12 months later (16 months after the last MDA) the taeniasis prevalence had returned to its original levels. Results of the pilot project emphasize the need of a multi-sectorial One-Health approach for the sustained control of T. solium. The parasite Taenia solium causes neurocysticercosis in humans in its larval stage and is the main cause of seizure disorders in poor communities that keep pigs (the intermediate host). Diagnosis and treatment of neurocysticercosis remains beyond the reach of the general population in Madagascar. Prevention is therefore the most suitable strategy for combating this disease. Mass drug administration (MDA) is used to treat communities for several parasitic diseases such as schistosomiasis. Infection with the T. solium tapeworm in people can be treated with MDA using praziquantel. Here, we conducted a pilot project in Madagascar, giving over 220,000 treatments to people in 52 villages once per year, for 3 consecutive years. The effects on taeniasis seemed to be encouraging when assessed 4 months after finishing the treatment, but 16 months later, the parasite’s prevalence had returned to its original level. MDA was effective in providing temporary control of taeniasis, but parasite transmission was not interrupted. With respect to T. solium, this highlights the need of incorporating other interventions such as vaccination and medication in pigs, improved pig husbandry and meat inspection to tackle the whole cycle of the parasite.
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Affiliation(s)
- Noromanana Sylvia Ramiandrasoa
- Service de Lutte contre les Maladies Epidémiques et Négligées, Ministère de la Santé Publique Analakely, Antananarivo, Madagascar
- * E-mail: (NSR); (MD)
| | - Pascaline Ravoniarimbinina
- Service de Lutte contre les Maladies Epidémiques et Négligées, Ministère de la Santé Publique Analakely, Antananarivo, Madagascar
| | - Armand Rafalimanantsoa Solofoniaina
- Service de Lutte contre les Maladies Epidémiques et Négligées, Ministère de la Santé Publique Analakely, Antananarivo, Madagascar
- Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | - Iharilanto Patricia Andrianjafy Rakotomanga
- Service de Lutte contre les Maladies Epidémiques et Négligées, Ministère de la Santé Publique Analakely, Antananarivo, Madagascar
- Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | | | | | - Anne-Marie Labouche
- Department of the Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Anna Sophie Fahrion
- Department of the Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Meritxell Donadeu
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Australia
- Initiative for Neglected Animal Diseases (INAND), Midrand, South Africa
- * E-mail: (NSR); (MD)
| | - Bernadette Abela-Ridder
- Department of the Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Davidra Rajaonatahina
- Centre Hospitalier Universitaire Joseph Ravoahangy Andrianavalona, Antananarivo, Madagascar
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Gabriël S, Mwape KE, Hobbs EC, Devleesschauwer B, Van Damme I, Zulu G, Mwelwa C, Mubanga C, Masuku M, Mambwe M, De Coster T, Phiri IK, Berkvens DL, Colston A, Bottieau E, Speybroeck N, Ketzis JK, Willingham AL, Trevisan C, Dorny P. Evidence for potential elimination of active Taenia solium transmission in Africa? N Engl J Med 2020; 383:396-397. [PMID: 32699455 PMCID: PMC7289521 DOI: 10.1056/nejmc1909955] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
| | | | - Emma C Hobbs
- Ross University School of Veterinary Medicine, Basseterre, St. Kitts
| | | | | | | | | | | | | | | | | | | | | | - Angie Colston
- Global Alliance for Livestock Veterinary Medicines, Nairobi, Kenya
| | | | | | - Jennifer K Ketzis
- Ross University School of Veterinary Medicine, Basseterre, St. Kitts
| | - A Lee Willingham
- Ross University School of Veterinary Medicine, Basseterre, St. Kitts
| | | | - Pierre Dorny
- Institute of Tropical Medicine, Antwerp, Belgium
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Chambaro HM, Sasaki M, Sinkala Y, Gonzalez G, Squarre D, Fandamu P, Lubaba C, Mataa L, Shawa M, Mwape KE, Gabriël S, Chembensofu M, Carr MJ, Hall WW, Qiu Y, Kajihara M, Takada A, Orba Y, Simulundu E, Sawa H. Evidence for exposure of asymptomatic domestic pigs to African swine fever virus during an inter-epidemic period in Zambia. Transbound Emerg Dis 2020; 67:2741-2752. [PMID: 32434281 DOI: 10.1111/tbed.13630] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 04/05/2020] [Accepted: 05/14/2020] [Indexed: 11/29/2022]
Abstract
African swine fever (ASF) causes persistent outbreaks in endemic and non-endemic regions in Zambia. However, the epidemiology of the disease is poorly understood, particularly during the inter-epidemic periods. We conducted surveillance for ASF in asymptomatic domestic pigs and soft ticks in selected Zambian provinces. While serum samples (n = 1,134) were collected from crossbred pigs from all study sites between 2014 and 2017, whole blood (n = 300) was collected from both crossbred and indigenous pigs in Eastern Province (EP) in 2017. Soft ticks were collected from Mosi-oa-Tunya National Park in Southern Province (SP) in 2019. Sera were screened for antibodies against ASF by ELISA while genome detection in whole blood and soft ticks was conducted by PCR. Ticks were identified morphologically and by phylogenetic analysis of the 16S rRNA gene. Seroprevalence was highest in EP (50.9%, 95% CI [47.0-54.9]) compared to significantly lower rates in SP (2.9%, 95% CI [1.6-5.1]). No antibodies to ASFV were detected in Lusaka Province. In EP, the prevalence of ASFV genome was 11.7% (35/300), significantly higher (OR = 6.2, 95% CI [2.4-16.6]) in indigenous pigs compared to crossbred pigs. The pooled prevalence of ASFV genome in ticks was 11.0%, 95% CI [8.5-13.9]. Free-range husbandry system was the only factor that was significantly associated with seropositive (p < .0001, OR = 39.3) and PCR-positive results (p < .001, OR = 5.7). Phylogenetically, based on the p72 gene, ASFV from Ornithodoros moubata ticks detected in this study belonged to genotype I, but they separated into two distinct clusters. Besides confirming ASF endemicity in EP and the presence of ASFV-infected ticks in SP, these results provide evidence for exposure of domestic pigs to ASFV in non-endemic regions during the inter-epidemic period.
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Affiliation(s)
- Herman M Chambaro
- Division of Molecular Pathobiology, Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan.,Ministry of Fisheries and Livestock, Lusaka, Zambia.,Virology Unit, Central Veterinary Research Institute, Lusaka, Zambia
| | - Michihito Sasaki
- Division of Molecular Pathobiology, Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Yona Sinkala
- Ministry of Fisheries and Livestock, Lusaka, Zambia
| | - Gabriel Gonzalez
- Division of Bioinformatics, Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - David Squarre
- Wildlife Veterinary Unit, Department of National Parks and Wildlife, Lusaka, Zambia.,Division of Collaboration and Education, Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan.,Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, Scotland
| | - Paul Fandamu
- Ministry of Fisheries and Livestock, Lusaka, Zambia
| | | | | | - Misheck Shawa
- Division of Infection and Immunity, Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Kabemba E Mwape
- Department of Clinical Studies, School of Veterinary Medicine, University of Zambia, Lusaka, Zambia
| | - Sarah Gabriël
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Mwelwa Chembensofu
- Department of Paraclinical Studies, School of Veterinary Medicine, University of Zambia, Lusaka, Zambia
| | - Michael J Carr
- Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo, Japan.,National Virus Reference Laboratory, School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland
| | - William W Hall
- Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo, Japan.,National Virus Reference Laboratory, School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland.,Global Virus Network, Baltimore, MD, USA
| | - Yongjin Qiu
- Hokudai Center for Zoonosis Control in Zambia, School of Veterinary Medicine, University of Zambia, Lusaka, Zambia
| | - Masahiro Kajihara
- Hokudai Center for Zoonosis Control in Zambia, School of Veterinary Medicine, University of Zambia, Lusaka, Zambia
| | - Ayato Takada
- Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo, Japan.,Division of Global Epidemiology, Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan.,Department of Disease Control, School of Veterinary Medicine, University of Zambia, Lusaka, Zambia
| | - Yasuko Orba
- Division of Molecular Pathobiology, Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Edgar Simulundu
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, Lusaka, Zambia
| | - Hirofumi Sawa
- Division of Molecular Pathobiology, Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan.,Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo, Japan.,Global Virus Network, Baltimore, MD, USA
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10
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Rossi GAM, Van Damme I, Gabriël S. Systematic review and meta-analysis of bovine cysticercosis in Brazil: current knowledge and way forward. Parasit Vectors 2020; 13:92. [PMID: 32085721 PMCID: PMC7035740 DOI: 10.1186/s13071-020-3971-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 02/14/2020] [Indexed: 12/21/2022] Open
Abstract
Background Taenia saginata taeniosis/cysticercosis has been well studied in several countries. Brazil is one of the most important beef exporting countries and has one of the highest cattle population size in the world. In this country, bovine cysticercosis (BCC) remains the most frequent reported zoonosis detected during post-mortem inspection, resulting in costs for the beef sector and public health. We performed a systematic literature review regarding data about BCC epidemiology in Brazil and meta-analyses for its prevalence in different administrative regions and the distribution over time, and based on this discussed possible control strategies. Methods A systematic review was conducted to obtain data about BCC in Brazil using the words “bovine cysticercosis” and “Brazil” to construct the search phrase. The inclusion criteria used to select articles were: (i) published from 2000 to 2018; (ii) full text available online in Portuguese or English; and (iii) contain information at least regarding one of the following aspects of BCC in Brazil: prevalence, incidence, spatial distribution, risk-factors, economic burden and measures for control. Results A set of 42 articles was included, covering the prevalence of BCC in Brazil, ranging between 0.01–18.75%. Prevalence results of 40 articles were included in a meta-analysis per administrative region. The highest prevalence was found in the South (3.4%; 95% CI: 2.0–5.2%), followed by the Southeast (2.7%; 95% CI: 1.9–3.6%), Northeast (1.5%; 95% CI: 0.6–2.7%), Central-western (0.9%; 95% CI: 0.3–1.7%) and North (0.0%; 95% CI: 0.0–0.6%) region. In addition, a reduction in prevalence over time was observed in all the evaluated states except for Alagoas and Pará. Conclusions Besides the large availability of data, a critical lack of information about BCC epidemiology remains in Brazil. Nevertheless, the available data on prevalence, high risk-areas and risk factors should contribute to a better understanding of transmission and the formulation of recommendations for control. A One Health approach will be required to reduce T. saginata taeniosis/cysticercosis prevalence and the consequent economic burden for the beef sector in Brazil, one of the most important beef exporters in the world.![]()
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Affiliation(s)
- Gabriel Augusto Marques Rossi
- Centro Universitário Central Paulista (UNICEP), Rua Miguel Petroni 5111, Postal Code 13563-470, São Carlos, São Paulo, Brazil.
| | - Inge Van Damme
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Sarah Gabriël
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
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11
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Dixon MA, Braae UC, Winskill P, Devleesschauwer B, Trevisan C, Van Damme I, Walker M, Hamley JID, Ramiandrasoa SN, Schmidt V, Gabriël S, Harrison W, Basáñez MG. Modelling for Taenia solium control strategies beyond 2020. Bull World Health Organ 2020; 98:198-205. [PMID: 32132754 PMCID: PMC7047036 DOI: 10.2471/blt.19.238485] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 12/15/2019] [Accepted: 12/27/2019] [Indexed: 01/06/2023] Open
Abstract
The cestode Taenia solium is responsible for a considerable cross-sectoral health and economic burden due to human neurocysticercosis and porcine cysticercosis. The 2012 World Health Organization (WHO) roadmap for neglected tropical diseases called for the development of a validated strategy for control of T. solium; however, such a strategy is not yet available. In 2019, WHO launched a global consultation aimed at refining the post-2020 targets for control of T. solium for a new roadmap for neglected tropical diseases. In response, two groups working on taeniasis and cysticercosis mathematical models (cystiSim and EPICYST models), together with a range of other stakeholders organized a workshop to provide technical input to the WHO consultation and develop a research plan to support efforts to achieve the post-2020 targets. The workshop led to the formation of a collaboration, CystiTeam, which aims to tackle the population biology, transmission dynamics, epidemiology and control of T. solium through mathematical modelling approaches. In this paper, we outline developments in T. solium control and in particular the use of modelling to help achieve post-2020 targets for control of T. solium. We discuss the steps involved in improving confidence in the predictive capacities of existing mathematical and computational models on T. solium transmission, including model comparison, refinement, calibration and validation. Expanding the CystiTeam partnership to other research groups and stakeholders, particularly those operating in different geographical and endemic areas, will enhance the prospects of improving the applicability of T. solium transmission models to inform taeniasis and cysticercosis control strategies.
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Affiliation(s)
- Matthew A Dixon
- Department of Infectious Disease Epidemiology, London Centre for Neglected Tropical Disease Research and MRC Centre for Global Infectious Disease Analysis, Imperial College London, London W2 1PG, England
| | - Uffe C Braae
- Department of Infectious Disease Epidemiology and Prevention, Statens Serum Institut, Copenhagen, Denmark
| | - Peter Winskill
- Department of Infectious Disease Epidemiology, London Centre for Neglected Tropical Disease Research and MRC Centre for Global Infectious Disease Analysis, Imperial College London, London W2 1PG, England
| | | | - Chiara Trevisan
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Inge Van Damme
- Department of Veterinary Public Health and Food Safety, Ghent University, Merelbeke, Belgium
| | - Martin Walker
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, England
| | - Jonathan I D Hamley
- Department of Infectious Disease Epidemiology, London Centre for Neglected Tropical Disease Research and MRC Centre for Global Infectious Disease Analysis, Imperial College London, London W2 1PG, England
| | - Sylvia N Ramiandrasoa
- Service de Lutte contre les Maladies Endémiques et Négligées, Ministry of Public Health, Antananarivo, Madagascar
| | - Veronika Schmidt
- Department of Neurology, Technical University Munich, Munich, Germany
| | - Sarah Gabriël
- Department of Veterinary Public Health and Food Safety, Ghent University, Merelbeke, Belgium
| | - Wendy Harrison
- Schistosomiasis Control Initiative Foundation, London, England
| | - Maria-Gloria Basáñez
- Department of Infectious Disease Epidemiology, London Centre for Neglected Tropical Disease Research and MRC Centre for Global Infectious Disease Analysis, Imperial College London, London W2 1PG, England
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12
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Neurocysticercosis Among Zambian Children and Adolescents With Human Immunodeficiency Virus: A Geographic Information Systems Approach. Pediatr Neurol 2020; 102:36-43. [PMID: 31492585 PMCID: PMC7864625 DOI: 10.1016/j.pediatrneurol.2019.07.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 07/27/2019] [Accepted: 07/29/2019] [Indexed: 11/20/2022]
Abstract
BACKGROUND Neurocysticercosis is the most common parasitic infection of the brain and a leading cause of epilepsy in resource-limited settings. Although neurocysticercosis and human immunodeficiency virus coinfections have commonly been reported, there are few data on how they interact. As part of an observational study of human immunodeficiency virus and cognition in Lusaka, Zambia, we identified a cluster of subjects with neurocysticercosis. We hypothesized that the neighborhood of residence may be an important factor driving clustering of neurocysticercosis and used a geographic information systems approach to investigate this association. METHODS A total of 34 subjects with human immunodeficiency virus and 13 subjects without human immunodeficiency virus (aged eight to 17 years) enrolled in the HIV-Associated Neurocognitive Disorders in Zambia study, had magnetic resonance imaging of the brain performed, and were evaluated for neurocysticercosis. Quantitative geographic information systems was utilized to investigate the relationship between neighborhood of residence, HIV, and neurocysticercosis. RESULTS Three of 34 subjects with human immunodeficiency virus (8.82%) and one of 13 controls were found to have neurocysticercosis. Geographic cluster analysis demonstrated that all subjects with neurocysticercosis were clustered in two adjacent neighborhoods (Chawama and Kanyama) with lower rates of piped water (Chawama: 22.8%, Kanyama: 26.7%) and flush toilets (Chawama: 14.0%, Kanyama: 14.0%) than the surrounding neighborhoods. CONCLUSION We describe a cluster of patients with both neurocysticercosis and human immunodeficiency virus in Lusaka. Cases of neurocysticercosis clustered in neighborhoods with low rates of piped water and limited access to flush toilets. Geographic information systems may be a useful approach for studying the relationship between human immunodeficiency virus and neurocysticercosis. Larger studies are necessary to further investigate this association.
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13
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The World Health Organization 2030 goals for Taenia solium: Insights and perspectives from transmission dynamics modelling: CystiTeam Group for Epidemiology and Modelling of Taenia solium Taeniasis/Cysticercosis. Gates Open Res 2019; 3:1546. [PMID: 31701092 PMCID: PMC6820453 DOI: 10.12688/gatesopenres.13068.2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2019] [Indexed: 12/14/2022] Open
Abstract
Taenia solium (TS), responsible for porcine cysticercosis, human taeniasis and (neuro)cysticercosis, was included in the World Health Organization neglected tropical disease (NTD) roadmap published in 2012. Targets set in this roadmap have not been met, but T. solium has been included in the consultation process for the new 2030 goals proposed for priority NTDs. Taenia solium transmission dynamics models can contribute to this process. A recent review has compared existing T. solium transmission models, identifying their similarities and differences in structure, parameterization and modelled intervention approaches. While a formal model comparison to investigate the impact of interventions is yet to be conducted, the models agree on the importance of coverage for intervention effectiveness and on the fact that human- and pig-focused interventions can be optimally combined. One of these models, cystiSim, an individual-based, stochastic model has been used to assess field-applicable interventions, some currently under evaluation in on-going trials in Zambia. The EPICYST, population-based, deterministic model has highlighted, based on simulating a generic sub-Saharan Africa setting, the higher efficacy (measured as the percentage of human cysticercosis cases prevented) of biomedical interventions (human and pig treatment and pig vaccination) compared to improved husbandry, sanitation, and meat inspection. Important questions remain regarding which strategies and combinations thereof provide sustainable solutions for severely resource-constrained endemic settings. Defining realistic timeframes to achieve feasible targets, and establishing suitable measures of effectiveness for these targets that can be quantified with current monitoring and evaluation tools, are current major barriers to identifying validated strategies. Taenia solium transmission models can support setting achievable 2030 goals; however, the refinement of these models is first required. Incorporating socio-economic elements, improved understanding of underlying biological processes, and consideration of spatial dynamics are key knowledge gaps that need addressing to support model development.
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The World Health Organization 2030 goals for Taenia solium: Insights and perspectives from transmission dynamics modelling: CystiTeam Group for Epidemiology and Modelling of Taenia solium Taeniasis/Cysticercosis. Gates Open Res 2019. [PMID: 31701092 DOI: 10.12688/gatesopenres.13068.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Taenia solium (TS), responsible for porcine cysticercosis, human taeniasis and (neuro)cysticercosis, was included in the World Health Organization neglected tropical disease (NTD) roadmap published in 2012. Targets set in this roadmap have not been met, but T. solium has been included in the consultation process for the new 2030 goals proposed for priority NTDs. Taenia solium transmission dynamics models can contribute to this process. A recent review has compared existing T. solium transmission models, identifying their similarities and differences in structure, parameterization and modelled intervention approaches. While a formal model comparison to investigate the impact of interventions is yet to be conducted, the models agree on the importance of coverage for intervention effectiveness and on the fact that human- and pig-focused interventions can be optimally combined. One of these models, cystiSim, an individual-based, stochastic model has been used to assess field-applicable interventions, some currently under evaluation in on-going trials in Zambia. The EPICYST, population-based, deterministic model has highlighted, based on simulating a generic sub-Saharan Africa setting, the higher efficacy (measured as the percentage of human cysticercosis cases prevented) of biomedical interventions (human and pig treatment and pig vaccination) compared to improved husbandry, sanitation, and meat inspection. Important questions remain regarding which strategies and combinations thereof provide sustainable solutions for severely resource-constrained endemic settings. Defining realistic timeframes to achieve feasible targets, and establishing suitable measures of effectiveness for these targets that can be quantified with current monitoring and evaluation tools, are current major barriers to identifying validated strategies. Taenia solium transmission models can support setting achievable 2030 goals; however, the refinement of these models is first required. Incorporating socio-economic elements, improved understanding of underlying biological processes, and consideration of spatial dynamics are key knowledge gaps that need addressing to support model development.
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15
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Braae UC, Lightowlers MW, Donadeu M. Can We Recommend Practical Interventions to Prevent Neurocysticercosis? Trends Parasitol 2019; 35:592-595. [PMID: 31151880 DOI: 10.1016/j.pt.2019.04.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 04/29/2019] [Accepted: 04/30/2019] [Indexed: 10/26/2022]
Abstract
The cystiSim model was used to compare strategies for the control of Taenia solium. A three-monthly intervention in pigs for 3 years was substantially more effective than biannual treatment for taeniasis in the human population for 5 years. The intervention period could be shortened further by combining pig and human interventions.
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Affiliation(s)
- Uffe Christian Braae
- Department of Infectious Disease Epidemiology and Prevention, Statens Serum Institut, DK-2300, Copenhagen, Denmark; One Health Center for Zoonoses and Tropical Veterinary Medicine, Ross University School of Veterinary Medicine, Basseterre, Saint Kitts and Nevis
| | - Marshall W Lightowlers
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, 250 Princes Highway, Werribee, Victoria 3030, Australia.
| | - Meritxell Donadeu
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, 250 Princes Highway, Werribee, Victoria 3030, Australia; Initiative for Neglected Animal Diseases (INAND), Whitby Manor Office Estate, 14th Road, Midrand, South Africa
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Strategies for tackling Taenia solium taeniosis/cysticercosis: A systematic review and comparison of transmission models, including an assessment of the wider Taeniidae family transmission models. PLoS Negl Trop Dis 2019; 13:e0007301. [PMID: 30969966 PMCID: PMC6476523 DOI: 10.1371/journal.pntd.0007301] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 04/22/2019] [Accepted: 03/13/2019] [Indexed: 01/03/2023] Open
Abstract
Background The cestode Taenia solium causes the neglected (zoonotic) tropical disease cysticercosis, a leading cause of preventable epilepsy in endemic low and middle-income countries. Transmission models can inform current scaling-up of control efforts by helping to identify, validate and optimise control and elimination strategies as proposed by the World Health Organization (WHO). Methodology/Principal findings A systematic literature search was conducted using the PRISMA approach to identify and compare existing T. solium transmission models, and related Taeniidae infection transmission models. In total, 28 modelling papers were identified, of which four modelled T. solium exclusively. Different modelling approaches for T. solium included deterministic, Reed-Frost, individual-based, decision-tree, and conceptual frameworks. Simulated interventions across models agreed on the importance of coverage for impactful effectiveness to be achieved. Other Taeniidae infection transmission models comprised force-of-infection (FoI), population-based (mainly Echinococcus granulosus) and individual-based (mainly E. multilocularis) modelling approaches. Spatial structure has also been incorporated (E. multilocularis and Taenia ovis) in recognition of spatial aggregation of parasite eggs in the environment and movement of wild animal host populations. Conclusions/Significance Gaps identified from examining the wider Taeniidae family models highlighted the potential role of FoI modelling to inform model parameterisation, as well as the need for spatial modelling and suitable structuring of interventions as key areas for future T. solium model development. We conclude that working with field partners to address data gaps and conducting cross-model validation with baseline and longitudinal data will be critical to building consensus-led and epidemiological setting-appropriate intervention strategies to help fulfil the WHO targets. Taenia solium infection in humans (taeniosis and neurocysticercosis) and pigs (cysticercosis) presents a significant global public health and economic challenge. The World Health Organization has called for validated strategies and wider consensus on which strategies are suitable for different epidemiological settings to support successful T. solium control and elimination efforts. Transmission models can be used to inform these strategies. Therefore, a modelling review was undertaken to assess the current state and gaps relating to T. solium epidemiological modelling. The literature surrounding models for other Taeniidae family infections was also considered, identifying approaches to aid further development of existing T. solium models. A variety of different modelling approaches have been used for T. solium including differences in structural and parametric assumptions associated with T. solium transmission biology. Despite these differences, all models agreed on the importance of coverage on intervention effectiveness. Other Taeniidae family models highlighted the need for incorporating spatial structure when necessary to capture aggregation of transmission stages in the environment and movement of animal hosts.
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