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Rosser JI, Tarpenning MS, Bramante JT, Tamhane A, Chamberlin AJ, Mutuku PS, De Leo GA, Ndenga B, Mutuku F, LaBeaud AD. Development of a trash classification system to map potential Aedes aegypti breeding grounds using unmanned aerial vehicle imaging. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:41107-41117. [PMID: 38842780 PMCID: PMC11189966 DOI: 10.1007/s11356-024-33801-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 05/20/2024] [Indexed: 06/07/2024]
Abstract
Aedes aegypti mosquitos are the primary vector for dengue, chikungunya, and Zika viruses and tend to breed in small containers of water, with a propensity to breed in small piles of trash and abandoned tires. This study piloted the use of aerial imaging to map and classify potential Ae. aegypti breeding sites with a specific focus on trash, including discarded tires. Aerial images of coastal and inland sites in Kenya were obtained using an unmanned aerial vehicle. Aerial images were reviewed for identification of trash and suspected trash mimics, followed by extensive community walk-throughs to identify trash types and mimics by description and ground photography. An expert panel reviewed aerial images and ground photos to develop a classification scheme and evaluate the advantages and disadvantages of aerial imaging versus walk-through trash mapping. A trash classification scheme was created based on trash density, surface area, potential for frequent disturbance, and overall likelihood of being a productive Ae. aegypti breeding site. Aerial imaging offers a novel strategy to characterize, map, and quantify trash at risk of promoting Ae. aegypti proliferation, generating opportunities for further research on trash associations with disease and trash interventions.
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Affiliation(s)
- Joelle I Rosser
- School of Medicine, Division of Infectious Diseases, Stanford University, Stanford, CA, USA.
| | | | | | | | - Andrew J Chamberlin
- Hopkins Marine Institute, Department of Earth System Sciences and Department of Oceans, Stanford University, Stanford, CA, USA
| | - Paul S Mutuku
- Division of Vector Borne Disease Control Unit, Msambweni County Referral Hospital, Msambweni, Kenya
| | - Giulio A De Leo
- Hopkins Marine Institute, Department of Earth System Sciences and Department of Oceans, Stanford University, Stanford, CA, USA
| | - Bryson Ndenga
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Francis Mutuku
- Department of Environment and Health Sciences, Technical University of Mombasa, Mombasa, Kenya
| | - Angelle Desiree LaBeaud
- School of Medicine, Division of Pediatric Infectious Diseases, Stanford University, Stanford, CA, USA
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Kiener M, Shayegh N, Nyathi SV, Ndenga BA, Mutuku FM, LaBeaud AD. Low Rate of Asymptomatic Dengue Infection Detected in Coastal Kenya Using Pooled Polymerase Chain Reaction Testing. Am J Trop Med Hyg 2024; 110:738-740. [PMID: 38471167 PMCID: PMC10993852 DOI: 10.4269/ajtmh.23-0650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 12/24/2023] [Indexed: 03/14/2024] Open
Abstract
Asymptomatic dengue virus (DENV) infections have important public health implications but are challenging to identify. We performed a cross-sectional study of reverse transcription quantitative polymerase chain reaction on pooled sera of asymptomatic individuals from the south coast of Kenya at two time periods to identify cases of asymptomatic viremia. Among 2,460 samples tested in pools of 9 or 10, we found only one positive case (0.04% incidence). Although pooling of samples has the potential to be a cost-effective and time-efficient method for asymptomatic DENV detection, mass cross-sectional pooled testing may not provide accurate data on rates of asymptomatic infection, likely owing to a decrease in the sensitivity with pooling of samples, a short period of viremia, or testing in the absence of an outbreak.
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Affiliation(s)
- Melanie Kiener
- Department of Medicine, Division of Infectious Diseases, Stanford University School of Medicine, Stanford, California
| | - Nader Shayegh
- Howard University College of Medicine, Washington, District of Columbia
| | - Sindiso Victor Nyathi
- Department of Medicine, Division of Infectious Diseases, Stanford University School of Medicine, Stanford, California
| | | | | | - Angelle Desiree LaBeaud
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Stanford University School of Medicine, Stanford, California
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Peña-García VH, Desiree LaBeaud A, Ndenga BA, Mutuku FM, Bisanzio DA, Mordecai EA, Andrews JR. Non-household environments make a major contribution to dengue transmission: Implications for vector control. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.01.08.24301016. [PMID: 38260355 PMCID: PMC10802645 DOI: 10.1101/2024.01.08.24301016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Aedes-borne pathogens have been increasing in incidence in recent decades despite vector control activities implemented in endemic settings. Vector control for Aedes-transmitted arboviruses typically focuses on households because vectors breed in household containers and bite indoors. Yet, our recent work shows a high abundance of Aedes spp. vectors in public spaces. To investigate the impact of non-household environments on dengue transmission and control, we used field data on the number of water containers and abundance of Aedes mosquitoes in Household (HH) and Non-Household (NH) environments in two Kenyan cities, Kisumu and Ukunda, from 2019-2022. Incorporating information on human activity space, we developed an agent-based model to simulate city-wide conditions considering HH and five types of NH environments in which people move and interact with other humans and vectors during peak biting times. We additionally evaluated the outcome of vector control activities implemented in different environments in preventive (before an epidemic) and reactive (after an epidemic commences) scenarios. We estimated that over half of infections take place in NH environments, where the main spaces for transmission are workplaces, markets, and recreational locations. Accordingly, results highlight the important role of vector control activities at NH locations to reduce dengue. A greater reduction of cases is expected as control activities are implemented earlier, at higher levels of coverage, with greater effectiveness when targeting only NH as opposed to when targeting only HH. Further, local ecological factors such as the differential abundance of water containers within cities are also influential factors to consider for control. This work provides insight into the importance of vector control in both household and non-household environments in endemic settings. It highlights a specific approach to inform evidence-based decision making to target limited vector control resources for optimal control.
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Affiliation(s)
- Victor Hugo Peña-García
- Department of Biology, Stanford University, Stanford, CA, USA
- School of Medicine, Stanford University, Stanford, CA, USA
| | | | | | - Francis M Mutuku
- Department of Environmental and Health Sciences, Technical University of Mombasa, Mombasa, Kenya
| | | | - Erin A Mordecai
- Department of Biology, Stanford University, Stanford, CA, USA
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Christofferson RC, Turner EA, Peña-García VH. Identifying Knowledge Gaps through the Systematic Review of Temperature-Driven Variability in the Competence of Aedes aegypti and Ae. albopictus for Chikungunya Virus. Pathogens 2023; 12:1368. [PMID: 38003832 PMCID: PMC10675276 DOI: 10.3390/pathogens12111368] [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: 10/31/2023] [Revised: 11/10/2023] [Accepted: 11/13/2023] [Indexed: 11/26/2023] Open
Abstract
Temperature is a well-known effector of several transmission factors of mosquito-borne viruses, including within mosquito dynamics. These dynamics are often characterized by vector competence and the extrinsic incubation period (EIP). Vector competence is the intrinsic ability of a mosquito population to become infected with and transmit a virus, while EIP is the time it takes for the virus to reach the salivary glands and be expectorated following an infectious bloodmeal. Temperatures outside the optimal range act on life traits, decreasing transmission potential, while increasing temperature within the optimal range correlates to increasing vector competence and a decreased EIP. These relatively well-studied effects of other Aedes borne viruses (dengue and Zika) are used to make predictions about transmission efficiency, including the challenges presented by urban heat islands and climate change. However, the knowledge of temperature and chikungunya (CHIKV) dynamics within its two primary vectors-Ae. aegypti and Ae. albopictus-remains less characterized, even though CHIKV remains a virus of public-health importance. Here, we review the literature and summarize the state of the literature on CHIKV and temperature dependence of vector competence and EIP and use these data to demonstrate how the remaining knowledge gap might confound the ability to adequately predict and, thus, prepare for future outbreaks.
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Affiliation(s)
| | - Erik A. Turner
- School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA;
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Nyangau PN, Nzuma JM, Irungu P, Junglen S, Kassie M. Health education impact on knowledge and management of arboviral diseases in Kenya: Evidence from randomised control trials. Glob Public Health 2023; 18:2274436. [PMID: 37902054 DOI: 10.1080/17441692.2023.2274436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 10/18/2023] [Indexed: 10/31/2023]
Abstract
Communities' knowledge and management strategies are crucial for mitigating and controlling the threat of existing and emerging diseases. In this study, we conducted randomised control trials (RCT) to examine the impact of health education on households' knowledge and management of three Arboviral Diseases (ADs); Rift Valley fever, Chikungunya fever, and Dengue fever in Kenya. The study was based on a sample of 629 households drawn from the three of Kenya's AD hotspot counties; Baringo, Kwale, and Kilifi. Employing a difference-in-difference method, our findings indicate that health education intervention significantly improved households' understanding of ADs transmission modes, causes, and prevention strategies. However, this intervention did not sufficiently influence households' disease management behaviour. We recommend the implementation of community engagement and outreach initiatives which have the potential to drive behavioural changes at the household level, thus enhancing the management and control of ADs in Kenya.
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Affiliation(s)
- Paul Nyamweya Nyangau
- Department of Agricultural Economics, Faculty of Agriculture, University of Nairobi, Nairobi, Kenya
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Jonathan Makau Nzuma
- Department of Agricultural Economics, Faculty of Agriculture, University of Nairobi, Nairobi, Kenya
| | - Patrick Irungu
- Department of Agricultural Economics, Faculty of Agriculture, University of Nairobi, Nairobi, Kenya
| | - Sandra Junglen
- Berlin Institute of Health, Institute of Virology, Charité - Universitätsmedizin Berlin, Corporate Member of Free University Berlin, Humboldt-University Berlin, Berlin, Germany
- German Centre for Infection Research (DZIF), Associated Partner Site Charité, Berlin, Germany
| | - Menale Kassie
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
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