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Zhou G, Githure J, Lee MC, Zhong D, Wang X, Atieli H, Githeko AK, Kazura J, Yan G. Malaria transmission heterogeneity in different eco-epidemiological areas of western Kenya: a region-wide observational and risk classification study for adaptive intervention planning. Malar J 2024; 23:74. [PMID: 38475793 PMCID: PMC10935946 DOI: 10.1186/s12936-024-04903-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 03/05/2024] [Indexed: 03/14/2024] Open
Abstract
BACKGROUND Understanding of malaria ecology is a prerequisite for designing locally adapted control strategies in resource-limited settings. The aim of this study was to utilize the spatial heterogeneity in malaria transmission for the designing of adaptive interventions. METHODS Field collections of clinical malaria incidence, asymptomatic Plasmodium infection, and malaria vector data were conducted from 108 randomly selected clusters which covered different landscape settings including irrigated farming, seasonal flooding area, lowland dryland farming, and highlands in western Kenya. Spatial heterogeneity of malaria was analyzed and classified into different eco-epidemiological zones. RESULTS There was strong heterogeneity and detected hot/cold spots in clinical malaria incidence, Plasmodium prevalence, and vector abundance. The study area was classified into four zones based on clinical malaria incidence, parasite prevalence, vector density, and altitude. The two irrigated zones have either the highest malaria incidence, parasite prevalence, or the highest malaria vector density; the highlands have the lowest vector density and parasite prevalence; and the dryland and flooding area have the average clinical malaria incidence, parasite prevalence and vector density. Different zones have different vector species, species compositions and predominant species. Both indoor and outdoor transmission may have contributed to the malaria transmission in the area. Anopheles gambiae sensu stricto (s.s.), Anopheles arabiensis, Anopheles funestus s.s., and Anopheles leesoni had similar human blood index and malaria parasite sporozoite rate. CONCLUSION The multi-transmission-indicator-based eco-epidemiological zone classifications will be helpful for making decisions on locally adapted malaria interventions.
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Affiliation(s)
- Guofa Zhou
- Program in Public Health, University of California, Irvine, CA, USA.
| | - John Githure
- Sub-Saharan International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, Kenya
| | - Ming-Chieh Lee
- Program in Public Health, University of California, Irvine, CA, USA
| | - Daibin Zhong
- Program in Public Health, University of California, Irvine, CA, USA
| | - Xiaoming Wang
- Program in Public Health, University of California, Irvine, CA, USA
| | - Harrysone Atieli
- Sub-Saharan International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, Kenya
| | - Andrew K Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - James Kazura
- Center for Global Health and Diseases, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Guiyun Yan
- Program in Public Health, University of California, Irvine, CA, USA
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Chan K, Konan KAC, Doudou DT, Kouadio GB, Lines J, Aunger R, N'Guessan R, Tusting LS. Rice farmers' knowledge, attitudes and practices towards mosquitoes in irrigation schemes in Côte d'Ivoire: a qualitative study. Malar J 2023; 22:352. [PMID: 37974248 PMCID: PMC10655379 DOI: 10.1186/s12936-023-04785-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 11/06/2023] [Indexed: 11/19/2023] Open
Abstract
BACKGROUND Irrigated rice cultivation in sub-Saharan Africa not only brings more malaria vectors to nearby communities, but also greater malaria risk. To aid the implementation of mosquito control in rice-growing communities, it is necessary to understand how farmers understand, view and manage their responsibility in mosquito generation and whether they are interested in coordinating to minimize it. METHODS Qualitative methods (observation grids, semi-structured in-depth interviews and focus group discussions) were used to reveal the perceptions of mosquitoes and their control in two irrigated rice farming communities in central Côte d'Ivoire near the M'bé and Lokapli irrigation schemes. RESULTS All rice farmers viewed mosquitoes as severe nuisances, and most acknowledged that they caused djèkouadjo (malaria) and were less numerous during harmattan (dry season). Many study participants believed that mosquitoes originated from grasses and stagnant water around villages. Only those living closer in proximity (~ 1 km) to the paddies believed that mosquitoes came from the bas-fonds (irrigated lowlands). However, they did not associate mosquito production with rice cultivation. Some farmers believed that there were more mosquitoes in recent years than historically because of the dam construction, but remarked on the importance of the dam (and bas-fonds) for their livelihood. Many farmers were not convinced that mosquito control could occur at farm-level. CONCLUSIONS To enhance accountability amongst rice farmers, there is a need for greater awareness on the rice-mosquito link, and emphasis that the link does not imply a trade-off between food production and health. Training should not only be directed towards farming communities, but also agricultural and health extension workers. Future riceland mosquito control methods must focus on improving crop productivity and address collective action problems that may occur.
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Affiliation(s)
- Kallista Chan
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK.
| | - Kouadio Aimé-Charles Konan
- Centre de Recherche Pour le Développement (CRD)/Laboratoire de Santé, Société et Développement, Université Alassane Ouattara, BP 01 V 18, Bouaké, Côte d'Ivoire
| | - Dimi Théodore Doudou
- Centre de Recherche Pour le Développement (CRD)/Laboratoire de Santé, Société et Développement, Université Alassane Ouattara, BP 01 V 18, Bouaké, Côte d'Ivoire
| | - Ghislain Brou Kouadio
- Centre de Recherche Pour le Développement (CRD)/Laboratoire de Santé, Société et Développement, Université Alassane Ouattara, BP 01 V 18, Bouaké, Côte d'Ivoire
| | - Jo Lines
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK
| | - Robert Aunger
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK
| | - Raphael N'Guessan
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK
- Institut Pierre Richet, Bouaké, Côte d'Ivoire
| | - Lucy S Tusting
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK
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Derua YA, Tungu PK, Malima RC, Mwingira V, Kimambo AG, Batengana BM, Machafuko P, Sambu EZ, Mgaya YD, Kisinza WN. Laboratory and semi-field evaluation of the efficacy of Bacillus thuringiensis var. israelensis (Bactivec®) and Bacillus sphaericus (Griselesf®) for control of mosquito vectors in northeastern Tanzania. CURRENT RESEARCH IN PARASITOLOGY & VECTOR-BORNE DISEASES 2022; 2:100089. [PMID: 35664894 PMCID: PMC9157456 DOI: 10.1016/j.crpvbd.2022.100089] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 04/11/2022] [Accepted: 04/27/2022] [Indexed: 10/25/2022]
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Rulisa A, van Kempen L, Mutesa L, Hakizimana E, Ingabire CM, Kateera F, Koenraadt CJM, van Vugt M, van den Borne B. Willingness to Contribute to Bio-Larviciding in the Fight against Malaria: A Contingent Valuation Study among Rice Farmers in Rwanda. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:11575. [PMID: 34770086 PMCID: PMC8583195 DOI: 10.3390/ijerph182111575] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/25/2021] [Accepted: 10/31/2021] [Indexed: 01/17/2023]
Abstract
There is broad consensus that successful and sustained larval source management (LSM) interventions, including bio-larviciding campaigns, require embeddedness in local community institutions. Ideally, these community structures should also be capable of mobilizing local resources to (co-)finance interventions. To date, farmer cooperatives, especially cooperatives of rice growers whose economic activity facilitates mosquito breeding, have remained under the radar in designing community-based bio-larviciding campaigns. This study explores the potential of rice farmer cooperatives in Bugesera district, Rwanda, to take up the aforementioned roles. To this purpose, we surveyed 320 randomly selected rice farmers who belonged to one of four rice cooperatives in the area and elicited their willingness-to-pay (WTP) for application of Bti, a popular bio-larvicide, in their rice paddies. Results from a (non-incentivized) bidding game procedure, which tested two alternative contribution schemes showed that financial contributions would be significantly different from zero and sufficient to carry a co-financing share of 15-25 per cent. A strong heterogeneity in mean WTP is revealed across cooperatives, in addition to variation among individual farmers, which needs to be anticipated when engaging farmer cooperatives in LSM.
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Affiliation(s)
- Alexis Rulisa
- Medical Research Centre Division, Rwanda Biomedical Centre, Kigali 7162, Rwanda;
- Department of Cultural Anthropology and Development Studies, Radboud University, 6525 Nijmegen, The Netherlands
| | - Luuk van Kempen
- Department of Cultural Anthropology and Development Studies, Radboud University, 6525 Nijmegen, The Netherlands
| | - Leon Mutesa
- Center for Human Genetics, College of Medicine and Health Sciences, University of Rwanda, Kigali 4285, Rwanda;
| | - Emmanuel Hakizimana
- Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Center, Kigali 7162, Rwanda;
| | - Chantal M. Ingabire
- Medical Research Centre Division, Rwanda Biomedical Centre, Kigali 7162, Rwanda;
| | - Fredrick Kateera
- Academic Medical Center, Department of Infectious Diseases, University of Amsterdam, 1012 Amsterdam, The Netherlands;
| | | | - Michèle van Vugt
- Center for Tropical Medicine and Travel Medicine, Academic Medical Center, University of Amsterdam, 1012 Amsterdam, The Netherlands;
| | - Bart van den Borne
- Department of Health Education & Promotion, Maastricht University, 6211 Maastricht, The Netherlands;
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Runge M, Mapua S, Nambunga I, Smith TA, Chitnis N, Okumu F, Pothin E. Evaluation of different deployment strategies for larviciding to control malaria: a simulation study. Malar J 2021; 20:324. [PMID: 34315473 PMCID: PMC8314573 DOI: 10.1186/s12936-021-03854-4] [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: 02/13/2021] [Accepted: 07/16/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Larviciding against malaria vectors in Africa has been limited to indoor residual spraying and insecticide-treated nets, but is increasingly being considered by some countries as a complementary strategy. However, despite progress towards improved larvicides and new tools for mapping or treating mosquito-breeding sites, little is known about the optimal deployment strategies for larviciding in different transmission and seasonality settings. METHODS A malaria transmission model, OpenMalaria, was used to simulate varying larviciding strategies and their impact on host-seeking mosquito densities, entomological inoculation rate (EIR) and malaria prevalence. Variations in coverage, duration, frequency, and timing of larviciding were simulated for three transmission intensities and four transmission seasonality profiles. Malaria transmission was assumed to follow rainfall with a lag of one month. Theoretical sub-Saharan African settings with Anopheles gambiae as the dominant vector were chosen to explore impact. Relative reduction compared to no larviciding was predicted for each indicator during the simulated larviciding period. RESULTS Larviciding immediately reduced the predicted host-seeking mosquito densities and EIRs to a maximum that approached or exceeded the simulated coverage. Reduction in prevalence was delayed by approximately one month. The relative reduction in prevalence was up to four times higher at low than high transmission. Reducing larviciding frequency (i.e., from every 5 to 10 days) resulted in substantial loss in effectiveness (54, 45 and 53% loss of impact for host-seeking mosquito densities, EIR and prevalence, respectively). In seasonal settings the most effective timing of larviciding was during or at the beginning of the rainy season and least impactful during the dry season, assuming larviciding deployment for four months. CONCLUSION The results highlight the critical role of deployment strategies on the impact of larviciding. Overall, larviciding would be more effective in settings with low and seasonal transmission, and at the beginning and during the peak densities of the target species populations. For maximum impact, implementers should consider the practical ranges of coverage, duration, frequency, and timing of larviciding in their respective contexts. More operational data and improved calibration would enable models to become a practical tool to support malaria control programmes in developing larviciding strategies that account for the diversity of contexts.
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Affiliation(s)
- Manuela Runge
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
| | - Salum Mapua
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Ismail Nambunga
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Thomas A Smith
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Nakul Chitnis
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Fredros Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Emilie Pothin
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland.,Clinton Health Access Initiative, Boston, USA
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Cissoko M, Sagara I, Sankaré MH, Dieng S, Guindo A, Doumbia Z, Allasseini B, Traore D, Fomba S, Bendiane MK, Landier J, Dessay N, Gaudart J. Geo-Epidemiology of Malaria at the Health Area Level, Dire Health District, Mali, 2013-2017. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E3982. [PMID: 32512740 PMCID: PMC7312793 DOI: 10.3390/ijerph17113982] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/25/2020] [Accepted: 05/26/2020] [Indexed: 12/28/2022]
Abstract
Background: According to the World Health Organization, there were more than 228 million cases of malaria globally in 2018, with 93% of cases occurring in Africa; in Mali, a 13% increase in the number of cases was observed between 2015 and 2018; this study aimed to evaluate the impact of meteorological and environmental factors on the geo-epidemiology of malaria in the health district of Dire, Mali. Methods: Meteorological and environmental variables were synthesized using principal component analysis and multiple correspondence analysis, the relationship between malaria incidence and synthetic indicators was determined using a multivariate general additive model; hotspots were detected by SaTScan. Results: Malaria incidence showed high inter and intra-annual variability; the period of high transmission lasted from September to February; health areas characterized by proximity to the river, propensity for flooding and high agricultural yield were the most at risk, with an incidence rate ratio of 2.21 with confidence intervals (95% CI: 1.85-2.58); malaria incidence in Dire declined from 120 to 20 cases per 10,000 person-weeks between 2013 and 2017. Conclusion: The identification of areas and periods of high transmission can help improve malaria control strategies.
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Affiliation(s)
- Mady Cissoko
- Malaria Research and Training Center—Ogobara K. Doumbo (MRTC-OKD), FMOS-FAPH, Mali-NIAID-ICER, Université des Sciences, des Techniques et des Technologies de Bamako, Bamako 1805, Mali; (I.S.); (A.G.); (J.G.)
- Aix Marseille Université (AMU), Institut national de la santé et de la recherche médicale (INSERM), Institut de Recherche pour le Développement (IRD), 13005 Marseille, France; (S.D.); (M.K.B.); (J.L.)
- Direction Régionale de la Santé de Tombouctou, Tombouctou 59, Mali; (M.H.S.); (Z.D.); (B.A.)
| | - Issaka Sagara
- Malaria Research and Training Center—Ogobara K. Doumbo (MRTC-OKD), FMOS-FAPH, Mali-NIAID-ICER, Université des Sciences, des Techniques et des Technologies de Bamako, Bamako 1805, Mali; (I.S.); (A.G.); (J.G.)
- Aix Marseille Université (AMU), Institut national de la santé et de la recherche médicale (INSERM), Institut de Recherche pour le Développement (IRD), 13005 Marseille, France; (S.D.); (M.K.B.); (J.L.)
| | - Moussa H. Sankaré
- Direction Régionale de la Santé de Tombouctou, Tombouctou 59, Mali; (M.H.S.); (Z.D.); (B.A.)
| | - Sokhna Dieng
- Aix Marseille Université (AMU), Institut national de la santé et de la recherche médicale (INSERM), Institut de Recherche pour le Développement (IRD), 13005 Marseille, France; (S.D.); (M.K.B.); (J.L.)
| | - Abdoulaye Guindo
- Malaria Research and Training Center—Ogobara K. Doumbo (MRTC-OKD), FMOS-FAPH, Mali-NIAID-ICER, Université des Sciences, des Techniques et des Technologies de Bamako, Bamako 1805, Mali; (I.S.); (A.G.); (J.G.)
- Mère et Enfant face aux Infections Tropicales (MERIT), IRD, Université Paris 5, 75006 Paris, France
| | - Zoumana Doumbia
- Direction Régionale de la Santé de Tombouctou, Tombouctou 59, Mali; (M.H.S.); (Z.D.); (B.A.)
| | - Balam Allasseini
- Direction Régionale de la Santé de Tombouctou, Tombouctou 59, Mali; (M.H.S.); (Z.D.); (B.A.)
| | - Diahara Traore
- Programme National de la Lutte contre le Paludisme (PNLP Mali), Bamako 233, Mali; (D.T.); (S.F.)
| | - Seydou Fomba
- Programme National de la Lutte contre le Paludisme (PNLP Mali), Bamako 233, Mali; (D.T.); (S.F.)
| | - Marc Karim Bendiane
- Aix Marseille Université (AMU), Institut national de la santé et de la recherche médicale (INSERM), Institut de Recherche pour le Développement (IRD), 13005 Marseille, France; (S.D.); (M.K.B.); (J.L.)
| | - Jordi Landier
- Aix Marseille Université (AMU), Institut national de la santé et de la recherche médicale (INSERM), Institut de Recherche pour le Développement (IRD), 13005 Marseille, France; (S.D.); (M.K.B.); (J.L.)
| | - Nadine Dessay
- ESPACE-DEV, UMR228 IRD/UM/UR/UG/UA, Institut de Recherche pour le Développement (IRD), 34093 Montpellier, France;
| | - Jean Gaudart
- Malaria Research and Training Center—Ogobara K. Doumbo (MRTC-OKD), FMOS-FAPH, Mali-NIAID-ICER, Université des Sciences, des Techniques et des Technologies de Bamako, Bamako 1805, Mali; (I.S.); (A.G.); (J.G.)
- Aix Marseille Université, APHM, INSERM, IRD, SESSTIM, Hop Timone, BioSTIC, Biostatistic & ICT, 13005 Marseille, France
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Derua YA, Kweka EJ, Kisinza WN, Githeko AK, Mosha FW. Bacterial larvicides used for malaria vector control in sub-Saharan Africa: review of their effectiveness and operational feasibility. Parasit Vectors 2019; 12:426. [PMID: 31470885 PMCID: PMC6716942 DOI: 10.1186/s13071-019-3683-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 08/23/2019] [Indexed: 12/19/2022] Open
Abstract
Several trials and reviews have outlined the potential role of larviciding for malaria control in sub-Saharan Africa (SSA) to supplement the core indoor insecticide-based interventions. It has been argued that widespread use of long-lasting insecticide-treated nets (LLINs) and indoor residual spraying (IRS) interventions in many parts of Africa result in many new areas with low and focal malaria transmission that can be targeted with larvicides. As some countries in SSA are making good progress in malaria control, larval source management, particularly with bacterial larvicides, could be included in the list of viable options to maintain the gains achieved while paving the way to malaria elimination. We conducted a review of published literature that investigated the application of bacterial larvicides, Bacillus thuringiensis var. israelensis (Bti) and/or Bacillus sphaericus (Bs) for malaria vector control in SSA. Data for the review were identified through PubMed, the extensive files of the authors and reference lists of relevant articles retrieved. A total of 56 relevant studies were identified and included in the review. The findings indicated that, at low application rates, bacterial larvicide products based on Bti and/or Bs were effective in controlling malaria vectors. The larvicide interventions were found to be feasible, accepted by the general community, safe to the non-target organisms and the costs compared fairly well with those of other vector control measures practiced in SSA. Our review suggests that larviciding should gain more ground as a tool for integrated malaria vector control due to the decline in malaria which creates more appropriate conditions for the intervention and to the recognition of limitations of insecticide-based vector control tools. The advancement of new technology for mapping landscapes and environments could moreover facilitate identification and targeting of the numerous larval habitats preferred by the African malaria vectors. To build sustainable anti-larval measures in SSA, there is a great need to build capacity in relevant specialties and develop organizational structures for governance and management of larval source management programmes.
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Affiliation(s)
- Yahya A Derua
- Kilimanjaro Christian Medical University College, Tumaini University Makumira, Moshi, Tanzania. .,National Institute for Medical Research, Amani Research Centre, Muheza, Tanga, Tanzania.
| | - Eliningaya J Kweka
- Division of Livestock and Human Diseases Vector Control, Tropical Pesticides Research Institute, Arusha, Tanzania.,Department of Medical Parasitology and Entomology, Catholic University of Health and Allied Sciences, Mwanza, Tanzania
| | - William N Kisinza
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanga, Tanzania
| | - Andrew K Githeko
- Climate and Human Health Research Unit, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Franklin W Mosha
- Kilimanjaro Christian Medical University College, Tumaini University Makumira, Moshi, Tanzania
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