1
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Klepac P, Hsieh JL, Ducker CL, Assoum M, Booth M, Byrne I, Dodson S, Martin DL, Turner CMR, van Daalen KR, Abela B, Akamboe J, Alves F, Brooker SJ, Ciceri-Reynolds K, Cole J, Desjardins A, Drakeley C, Ediriweera DS, Ferguson NM, Gabrielli AF, Gahir J, Jain S, John MR, Juma E, Kanayson P, Deribe K, King JD, Kipingu AM, Kiware S, Kolaczinski J, Kulei WJ, Laizer TL, Lal V, Lowe R, Maige JS, Mayer S, McIver L, Mosser JF, Nicholls RS, Nunes-Alves C, Panjwani J, Parameswaran N, Polson K, Radoykova HS, Ramani A, Reimer LJ, Reynolds ZM, Ribeiro I, Robb A, Sanikullah KH, Smith DRM, Shirima GG, Shott JP, Tidman R, Tribe L, Turner J, Vaz Nery S, Velayudhan R, Warusavithana S, Wheeler HS, Yajima A, Abdilleh AR, Hounkpatin B, Wangmo D, Whitty CJM, Campbell-Lendrum D, Hollingsworth TD, Solomon AW, Fall IS. Climate change, malaria and neglected tropical diseases: a scoping review. Trans R Soc Trop Med Hyg 2024; 118:561-579. [PMID: 38724044 PMCID: PMC11367761 DOI: 10.1093/trstmh/trae026] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 03/27/2024] [Accepted: 04/02/2024] [Indexed: 09/03/2024] Open
Abstract
To explore the effects of climate change on malaria and 20 neglected tropical diseases (NTDs), and potential effect amelioration through mitigation and adaptation, we searched for papers published from January 2010 to October 2023. We descriptively synthesised extracted data. We analysed numbers of papers meeting our inclusion criteria by country and national disease burden, healthcare access and quality index (HAQI), as well as by climate vulnerability score. From 42 693 retrieved records, 1543 full-text papers were assessed. Of 511 papers meeting the inclusion criteria, 185 studied malaria, 181 dengue and chikungunya and 53 leishmaniasis; other NTDs were relatively understudied. Mitigation was considered in 174 papers (34%) and adaption strategies in 24 (5%). Amplitude and direction of effects of climate change on malaria and NTDs are likely to vary by disease and location, be non-linear and evolve over time. Available analyses do not allow confident prediction of the overall global impact of climate change on these diseases. For dengue and chikungunya and the group of non-vector-borne NTDs, the literature privileged consideration of current low-burden countries with a high HAQI. No leishmaniasis papers considered outcomes in East Africa. Comprehensive, collaborative and standardised modelling efforts are needed to better understand how climate change will directly and indirectly affect malaria and NTDs.
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Affiliation(s)
- Petra Klepac
- Big Data Institute, Oxford University, Oxford, UK
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, UK
| | - Jennifer L Hsieh
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Camilla L Ducker
- Global Neglected Tropical Diseases Programme, World Health Organization, Geneva, Switzerland
| | - Mohamad Assoum
- The Kirby Institute, University of New South Wales, Sydney, Australia
| | - Mark Booth
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Isabel Byrne
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK
| | | | - Diana L Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - C Michael R Turner
- Global Neglected Tropical Diseases Programme, World Health Organization, Geneva, Switzerland
- Division of Infection and Immunity, University of Glasgow, Glasgow, UK
| | - Kim R van Daalen
- Barcelona Supercomputing Center (BSC), Barcelona, Spain
- British Heart Foundation Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
- Victor Phillip Dahdaleh Heart and Lung Research Institute, University of Cambridge, Cambridge, UK
| | - Bernadette Abela
- Global Neglected Tropical Diseases Programme, World Health Organization, Geneva, Switzerland
| | - Jennifer Akamboe
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Fabiana Alves
- Drugs for Neglected Diseases initiative, Geneva, Switzerland
| | - Simon J Brooker
- Neglected Tropical Diseases, Bill & Melinda Gates Foundation, Seattle, WA, USA
- Department of Global Health, University of Washington, Seattle, WA, USA
| | - Karen Ciceri-Reynolds
- Global Neglected Tropical Diseases Programme, World Health Organization, Geneva, Switzerland
| | | | - Aidan Desjardins
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK
| | - Dileepa S Ediriweera
- CHICAS, Lancaster University, Lancaster, UK
- Faculty of Medicine, University of Kelaniya, Kelaniya, Sri Lanka
| | - Neil M Ferguson
- School of Public Health, Imperial College London, London, UK
| | | | - Joshua Gahir
- Queen Elizabeth Hospital, Lewisham and Greenwich NHS Trust, London, UK
| | - Saurabh Jain
- Global Neglected Tropical Diseases Programme, World Health Organization, Geneva, Switzerland
| | - Mbaraka R John
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
| | - Elizabeth Juma
- Expanded Special Project for Elimination of Neglected Tropical Diseases, Regional Office for Africa, World Health Organization, Brazzaville, Republic of Congo
| | - Priya Kanayson
- Global Institute for Disease Elimination, Abu Dhabi, United Arab Emirates
| | - Kebede Deribe
- Department of Neglected Tropical Diseases, Children's Investment Fund Foundation, Addis Ababa, Ethiopia
| | - Jonathan D King
- Global Neglected Tropical Diseases Programme, World Health Organization, Geneva, Switzerland
| | - Andrea M Kipingu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
| | - Samson Kiware
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
- Research and Knowledge Management, Pan-African Mosquito Control Association, Nairobi, Kenya
| | - Jan Kolaczinski
- Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | - Winnie J Kulei
- Pure and Applied Mathematics, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
- Mathematics, Statistics and Actuarial Science, Karatina University, Karatina, Kenya
| | - Tajiri L Laizer
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
| | - Vivek Lal
- Global Leprosy Programme, World Health Organization, New Delhi, India
| | - Rachel Lowe
- Barcelona Supercomputing Center (BSC), Barcelona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
- Centre on Climate Change & Planetary Health and Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Janice S Maige
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
| | - Sam Mayer
- Global Strategic Partnerships, The END Fund, New York, NY, USA
| | - Lachlan McIver
- Médecins Sans Frontières, Operational Centre Geneva, Geneva, Switzerland
| | - Jonathan F Mosser
- Institute for Health Metrics and Evaluation, University of Washington, Seattle WA, USA
| | - Ruben Santiago Nicholls
- Department of Communicable Diseases Prevention, Control and Elimination, Pan American Health Organization, Washington DC, USA
| | | | | | - Nishanth Parameswaran
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Karen Polson
- Department of Social and Environmental Determinants of Health Equity, Pan American Health Organization, Washington DC, USA
| | | | - Aditya Ramani
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, UK
| | - Lisa J Reimer
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | | | - Isabela Ribeiro
- Drugs for Neglected Diseases initiative, Geneva, Switzerland
| | - Alastair Robb
- Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | - Kazim Hizbullah Sanikullah
- Integrated Communicable Disease Unit, Regional Office for the Western Pacific, World Health Organization, Manilla, Philippines
| | - David R M Smith
- Health Economics Research Centre, Nuffield Department of Population Health, University of Oxford, UK
| | - GloriaSalome G Shirima
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
- School of Computational and Communication Science and Engineering, The Nelson Mandela African Institution of Science and Technology, Arusha, United Republic of Tanzania
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Joseph P Shott
- Division of Neglected Tropical Diseases, Global Health Bureau, United States Agency for International Development, Washington DC, USA
| | - Rachel Tidman
- Science Department, World Organisation for Animal Health, Paris, France
| | - Louisa Tribe
- Department of Communications, Uniting to Combat Neglected Tropical Diseases, London, UK
| | | | - Susana Vaz Nery
- The Kirby Institute, University of New South Wales, Sydney, Australia
| | - Raman Velayudhan
- Global Neglected Tropical Diseases Programme, World Health Organization, Geneva, Switzerland
| | - Supriya Warusavithana
- Neglected Tropical Disease Control, Regional Office for the Eastern Mediterranean, World Health Organization, Cairo, Egypt
| | - Holly S Wheeler
- Office of Development Affairs, Presidential Court, Abu Dhabi, United Arab Emirates
| | - Aya Yajima
- Vector-Borne and Neglected Tropical Diseases Control, Regional Office for South-East Asia, World Health Organization, New Delhi, India
| | | | | | | | | | | | | | - Anthony W Solomon
- Global Neglected Tropical Diseases Programme, World Health Organization, Geneva, Switzerland
| | - Ibrahima Socé Fall
- Global Neglected Tropical Diseases Programme, World Health Organization, Geneva, Switzerland
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2
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Kyomuhangi I, Giorgi E. A threshold-free approach with age-dependency for estimating malaria seroprevalence. Malar J 2022; 21:1. [PMID: 34980109 PMCID: PMC8725324 DOI: 10.1186/s12936-021-04022-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 12/12/2021] [Indexed: 11/21/2022] Open
Abstract
Background In malaria serology analysis, the standard approach to obtain seroprevalence, i.e the proportion of seropositive individuals in a population, is based on a threshold which is used to classify individuals as seropositive or seronegative. The choice of this threshold is often arbitrary and is based on methods that ignore the age-dependency of the antibody distribution. Methods Using cross-sectional antibody data from the Western Kenyan Highlands, this paper introduces a novel approach that has three main advantages over the current threshold-based approach: it avoids the use of thresholds; it accounts for the age dependency of malaria antibodies; and it allows us to propagate the uncertainty from the classification of individuals into seropositive and seronegative when estimating seroprevalence. The reversible catalytic model is used as an example for illustrating how to propagate this uncertainty into the parameter estimates of the model. Results This paper finds that accounting for age-dependency leads to a better fit to the data than the standard approach which uses a single threshold across all ages. Additionally, the paper also finds that the proposed threshold-free approach is more robust against the selection of different age-groups when estimating seroprevalence. Conclusion The novel threshold-free approach presented in this paper provides a statistically principled and more objective approach to estimating malaria seroprevalence. The introduced statistical framework also provides a means to compare results across studies which may use different age ranges for the estimation of seroprevalence. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-04022-4.
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Affiliation(s)
- Irene Kyomuhangi
- CHICAS, Lancaster University, Sir John Fisher Drive, Lancaster, UK.
| | - Emanuele Giorgi
- CHICAS, Lancaster University, Sir John Fisher Drive, Lancaster, UK
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Hurtado L, Cumbrera A, Rigg C, Perea M, Santamaría AM, Chaves LF, Moreno D, Romero L, Lasso J, Caceres L, Saldaña A, Calzada JE. Long-term transmission patterns and public health policies leading to malaria elimination in Panamá. Malar J 2020; 19:265. [PMID: 32703206 PMCID: PMC7376851 DOI: 10.1186/s12936-020-03329-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 07/09/2020] [Indexed: 11/23/2022] Open
Abstract
Background The present study provides a countrywide perspective of the malaria situation in Panamá over a long-term framework, with the purpose of identifying historical malaria resurgence events and their potential causes. Methods A descriptive-ecological study was conducted by analysing demographic and epidemiological annual malaria time series data in Panamá (1884–2019) using several data sources. Malaria intensity indicators were calculated during the study period. The effects of El Niño Southern Oscillation on malaria transmission were also analysed using a retrospective analysis of malaria cases between 1957 and 2019. Results Several factors were identified responsible for malaria resurgence in Panamá, mostly related with Malaria Control Programme weakening. During the past 20 years (2000–2019) malaria has progressively increased in prevalence within indigenous settlements, with a predominance of male cases and a high proportion (15% of total cases) in children less than 5 years old. During this period, a significant and increasing proportion of the Plasmodium falciparum cases were imported. Retrospective analysis (1957–2019) evidenced that ENSO had a significant impact on malaria transmission dynamics in Panamá. Conclusions Data analysis confirmed that although authorities have been successful in focalizing malaria transmission in the country, there are still neglected issues to be solved and important intercultural barriers that need to be addressed in order to achieve elimination of the disease by 2022. This information will be useful for targeting strategies by the National Malaria Elimination Programme.
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Affiliation(s)
- Lisbeth Hurtado
- Departamento de Análisis Epidemiológico y Bioestadísticas, Instituto Conmemorativo Gorgas de Estudios de la Salud, Panamá, República de Panamá.,Universidad de Panamá, Panamá, República de Panamá
| | - Alberto Cumbrera
- Dirección de Investigación y Desarrollo Tecnológico, Instituto Conmemorativo Gorgas de Estudios de la Salud, Panamá, República de Panamá
| | - Chystrie Rigg
- Departamento de Investigación en Parasitología, Instituto Conmemorativo Gorgas de Estudios de la Salud, Panamá, República de Panamá
| | - Milixa Perea
- Departamento de Investigación en Parasitología, Instituto Conmemorativo Gorgas de Estudios de la Salud, Panamá, República de Panamá
| | - Ana María Santamaría
- Departamento de Investigación en Parasitología, Instituto Conmemorativo Gorgas de Estudios de la Salud, Panamá, República de Panamá
| | - Luis Fernando Chaves
- Instituto Costarricense de Investigación Y Enseñanza en Nutrición Y Salud (INCIENSA), Tres Ríos, Cartago, Costa Rica
| | - Dianik Moreno
- Laboratorio Central de Referencia en Salud Publica, Instituto Conmemorativo Gorgas de Estudios de la Salud, Panamá, República de Panamá
| | - Luis Romero
- Laboratorio Central de Referencia en Salud Publica, Instituto Conmemorativo Gorgas de Estudios de la Salud, Panamá, República de Panamá
| | - Jose Lasso
- Departamento de Control de Vectores, Ministerio de Salud (MINSA), Panamá, República de Panamá
| | - Lorenzo Caceres
- Departamento de Investigación en Entomología Médica, Instituto Conmemorativo Gorgas de Estudios de la Salud, Panamá, República de Panamá
| | - Azael Saldaña
- Universidad de Panamá, Panamá, República de Panamá.,Departamento de Investigación en Parasitología, Instituto Conmemorativo Gorgas de Estudios de la Salud, Panamá, República de Panamá
| | - Jose E Calzada
- Universidad de Panamá, Panamá, República de Panamá. .,Departamento de Investigación en Parasitología, Instituto Conmemorativo Gorgas de Estudios de la Salud, Panamá, República de Panamá.
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4
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Malaria Elimination in Costa Rica: Changes in Treatment and Mass Drug Administration. Microorganisms 2020; 8:microorganisms8070984. [PMID: 32630155 PMCID: PMC7409053 DOI: 10.3390/microorganisms8070984] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/04/2020] [Accepted: 05/11/2020] [Indexed: 12/27/2022] Open
Abstract
Costa Rica is a candidate to eliminate malaria by 2020. The remaining malaria transmission hotspots are located within the Huétar Norte Region (HNR), where 90% of the country's 147 malaria cases have occurred since 2016, following a 33-month period without transmission. Here, we examine changes in transmission with the implementation of a supervised seven-day chloroquine and primaquine treatment (7DCPT). We also evaluate the impact of a focal mass drug administration (MDA) in January 2019 at Boca Arenal, the town in HNR reporting the greatest local transmission. We found that the change to a seven-day treatment protocol, from the prior five-day program, was associated with a 98% reduction in malaria transmission. The MDA helped to reduce transmission, keeping the basic reproduction number, RT, significantly below 1, for at least four months. However, following new imported cases from Nicaragua, autochthonous transmission resumed. Our results highlight the importance of appropriate treatment delivery to reduce malaria transmission, and the challenge that highly mobile populations, if their malaria is not treated, pose to regional elimination efforts in Mesoamerica and México.
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5
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Giesen C, Roche J, Redondo-Bravo L, Ruiz-Huerta C, Gomez-Barroso D, Benito A, Herrador Z. The impact of climate change on mosquito-borne diseases in Africa. Pathog Glob Health 2020; 114:287-301. [PMID: 32584659 PMCID: PMC7480509 DOI: 10.1080/20477724.2020.1783865] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Despite being one of the continents with the least greenhouse gas emissions, no continent
is being struck as severely by climate change (CC) as Africa. Mosquito-borne diseases
(MBD) cause major human diseases in this continent. Current knowledge suggests that MBD
range could expand dramatically in response to CC. This study aimed at assessing the
relationship between CC and MBD in Africa. Methods For this purpose, a systematic peer
review was carried out, considering all articles indexed in PubMed, Scopus, Embase and
CENTRAL. Search terms referring to MBD, CC and environmental factors were screened in
title, abstract and keywords.Results A total of twenty-nine studies were included, most of
them on malaria (61%), being Anopheles spp. (61%) the most
commonly analyzed vector, mainly in Eastern Africa (48%). Seventy-nine percent of these
studies were based on predictive models. Seventy-two percent of the reviewed studies
considered that CC impacts on MBD epidemiology. MBD prevalence will increase according to
69% of the studies while 17% predicted a decrease. MBD expansion throughout the continent
was also predicted. Most studies showed a positive relationship between observed or
predicted results and CC. However, there was a great heterogeneity in methodologies and a
tendency to reductionism, not integrating other variables that interact with both the
environment and MBD. In addition, most results have not yet been tested. A global health
approach is desirable in this kind of research. Nevertheless, we cannot wait for science
to approve something that needs to be addressed now to avoid greater effects in the
future.
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Affiliation(s)
- Christine Giesen
- Unidad de Medicina Preventiva, Hospital Universitario Infanta Sofía , Madrid, Spain
| | - Jesús Roche
- Escuela Nacional de Sanidad, Instituto de Salud Carlos III (ISCIII) , Madrid, Spain
| | - Lidia Redondo-Bravo
- Servicio de Medicina Preventiva, Hospital Universitario la Paz , Madrid, Spain
| | - Claudia Ruiz-Huerta
- Servicio de Medicina Preventiva, Hospital Universitario de la Cruz Roja , Madrid, Spain
| | - Diana Gomez-Barroso
- Centro Nacional de Epidemiología, Instituto de Salud Carlos III (ISCIII) , Madrid, Spain.,Consorcio de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP) , Madrid, Spain
| | - Agustin Benito
- Centro Nacional de Medicina Tropical, Instituto de Salud Carlos III (ISCIII) , Madrid, Spain.,Red de Investigación Cooperativa en Enfermedades Tropicales (RICET) , Madrid, Spain
| | - Zaida Herrador
- Centro Nacional de Medicina Tropical, Instituto de Salud Carlos III (ISCIII) , Madrid, Spain.,Red de Investigación Cooperativa en Enfermedades Tropicales (RICET) , Madrid, Spain
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6
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Kamau A, Mogeni P, Okiro EA, Snow RW, Bejon P. A systematic review of changing malaria disease burden in sub-Saharan Africa since 2000: comparing model predictions and empirical observations. BMC Med 2020; 18:94. [PMID: 32345315 PMCID: PMC7189714 DOI: 10.1186/s12916-020-01559-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 03/16/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The most widely used measures of declining burden of malaria across sub-Saharan Africa are predictions from geospatial models. These models apply spatiotemporal autocorrelations and covariates to parasite prevalence data and then use a function of parasite prevalence to predict clinical malaria incidence. We attempted to assess whether trends in malaria cases, based on local surveillance, were similar to those captured by Malaria Atlas Project (MAP) incidence surfaces. METHODS We undertook a systematic review (PROSPERO International Prospective Register of Systematic Reviews; ID = CRD42019116834) to identify empirical data on clinical malaria in Africa since 2000, where reports covered at least 5 continuous years. The trends in empirical data were then compared with the trends of time-space matched clinical malaria incidence from MAP using the Spearman rank correlation. The correlations (rho) between changes in empirically observed and modelled estimates of clinical malaria were displayed by forest plots and examined by meta-regression. RESULTS Sixty-seven articles met our inclusion criteria representing 124 sites from 24 African countries. The single most important factor explaining the correlation between empirical observations and modelled predictions was the slope of empirically observed data over time (rho = - 0.989; 95% CI - 0.998, - 0.939; p < 0.001), i.e. steeper declines were associated with a stronger correlation between empirical observations and modelled predictions. Factors such as quality of study, reported measure of malaria and endemicity were only slightly predictive of such correlations. CONCLUSIONS In many locations, both local surveillance data and modelled estimates showed declines in malaria burden and hence similar trends. However, there was a weak association between individual surveillance datasets and the modelled predictions where stalling in progress or resurgence of malaria burden was empirically observed. Surveillance data were patchy, indicating a need for improved surveillance to strengthen both empiric reporting and modelled predictions.
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Affiliation(s)
- Alice Kamau
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
| | | | | | - Robert W Snow
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Philip Bejon
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
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7
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Abstract
Costa Rica is near malaria elimination. This achievement has followed shifts in malaria health policy. Here, we evaluate the impacts that different health policies have had on malaria transmission in Costa Rica from 1913 to 2018. We identified regime shifts and used regression models to measure the impact of different health policies on malaria transmission in Costa Rica using annual case records. We found that vector control and prophylactic treatments were associated with a 50% malaria case reduction in 1929-1931 compared with 1913-1928. DDT introduction in 1946 was associated with an increase in annual malaria case reduction from 7.6% (1942-1946) to 26.4% (1947-1952). The 2006 introduction of 7-day supervised chloroquine and primaquine treatments was the most effective health policy between 1957 and 2018, reducing annual malaria cases by 98% (2009-2018) when compared with 1957-1968. We also found that effective malaria reduction policies have been sensitive to natural catastrophes and extreme climatic events, both of which have increased malaria transmission in Costa Rica. Currently, outbreaks follow malaria importation into vulnerable areas of Costa Rica. This highlights the need to timely diagnose and treat malaria, while improving living standards, in the affected areas.
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8
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Cook J, Owaga C, Marube E, Baidjoe A, Stresman G, Migiro R, Cox J, Drakeley C, Stevenson JC. Risk factors for Plasmodium falciparum infection in the Kenyan Highlands: a cohort study. Trans R Soc Trop Med Hyg 2020; 113:152-159. [PMID: 30496556 PMCID: PMC6391934 DOI: 10.1093/trstmh/try122] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 09/06/2018] [Accepted: 11/22/2018] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Malaria transmission in African highland areas can be prone to epidemics, with minor fluctuations in temperature or altitude resulting in highly heterogeneous transmission. In the Kenyan Highlands, where malaria prevalence has been increasing, characterising malaria incidence and identifying risk factors for infection is complicated by asymptomatic infection. METHODS This all-age cohort study, one element of the Malaria Transmission Consortium, involved monthly follow-up of 3155 residents of the Kisii and Rachuonyo South districts during June 2009-June 2010. Participants were tested for malaria using rapid diagnostic testing at every visit, regardless of symptoms. RESULTS The incidence of Plasmodium falciparum infection was 0.2 cases per person, although infections were clustered within individuals and over time, with the majority of infections detected in the last month of the cohort study. Overall, incidence was higher in the Rachuonyo district and infections were detected most frequently in 5-10-year-olds. The majority of infections were asymptomatic (58%). Travel away from the study area was a notable risk factor for infection. CONCLUSIONS Identifying risk factors for malaria infection can help to guide targeting of interventions to populations most likely to be exposed to malaria.
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Affiliation(s)
- Jackie Cook
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Chrispin Owaga
- Evidence Action, Ngong Road, Nairobi, Kenya.,Kenya Medical Research Institute (KEMRI), KEMRI-Wellcome Trust Research Programme, Kemri Square, Kilifi, Kenya
| | | | | | - Gillian Stresman
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Robin Migiro
- Kenya Medical Research Institute (KEMRI), KEMRI-Wellcome Trust Research Programme, Kemri Square, Kilifi, Kenya
| | - Jon Cox
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Chris Drakeley
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Jennifer C Stevenson
- Macha Research Trust, Choma, Southern Province, Zambia.,Johns Hopkins Malaria Research Institute, Bloomberg School of Public Health, Baltimore, USA
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9
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Wang Y, Yim SHL, Yang Y, Morin CW. The effect of urbanization and climate change on the mosquito population in the Pearl River Delta region of China. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2020; 64:501-512. [PMID: 31811391 DOI: 10.1007/s00484-019-01837-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 11/19/2019] [Accepted: 11/21/2019] [Indexed: 06/10/2023]
Abstract
The rising incidence of mosquito-borne diseases is a global concern. Changes in regional climate, due to urbanization and global greenhouse gas concentrations, may affect the ecology of mosquitoes and mosquito-transmitted pathogens. The effects of changes in climate on mosquito population dynamics are complex but critical and urgent for implementing more effective public health policies. This study quantified the impact of urbanization and global climate change on the population of the mosquito species, Culex quinquefasciatus, in the Pearl River Delta region in southern China-an area that has undergone substantial urbanization and is expected to experience changes in climate. This study employed a mechanistic model to simulate mosquito population dynamics under various greenhouse gas emission and land-cover change scenarios based on climate data provided by a state-of-the-art regional climate model. Our results show a 12.6% decrease in the annual mosquito population in newly urbanized areas and a 5.9% increase in the annual mosquito population in existing urban areas. Furthermore, changing climate conditions are projected to cause a 15-17% reduction in the total annual mosquito population; however, the change will not be uniform throughout the year. Peak months exhibit a reduction in population, whereas non-peak months show a significant increase. These findings suggest mosquito control strategies may need to be adjusted to respond to the impacts of urbanization and climate change on mosquito population dynamics to maximize effectiveness. Region specific, quantitative analyses of environmental impacts on mosquito-borne disease ecology, like this study, are needed to provide policy makers with a scientific reference to guide the formation of effective transmission intervention strategies.
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Affiliation(s)
- Yongli Wang
- Institute of Environment, Energy and Sustainability, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
| | - Steve Hung Lam Yim
- Institute of Environment, Energy and Sustainability, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
- Department of Geography and Resource Management, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
- Stanley Ho Big Data Decision Analytics Research Centre, The Chinese University of Hong Kon, Shatin, N.T., Hong Kong, China.
| | - Yuanjian Yang
- Institute of Environment, Energy and Sustainability, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
| | - Cory W Morin
- Department of Global Health, University of Washington, Seattle, WA, USA
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Sankaran S, Majumder S, Viswanathan A, Guttal V. Clustering and correlations: Inferring resilience from spatial patterns in ecosystems. Methods Ecol Evol 2019. [DOI: 10.1111/2041-210x.13304] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sumithra Sankaran
- Centre for Ecological Sciences Indian Institute of Science Bengaluru India
| | - Sabiha Majumder
- Centre for Ecological Sciences Indian Institute of Science Bengaluru India
- Institut für Integrative Biologie ETH Zurich Zürich Switzerland
| | - Ashwin Viswanathan
- Centre for Ecological Sciences Indian Institute of Science Bengaluru India
- Nature Conservation Foundation Bengaluru India
| | - Vishwesha Guttal
- Centre for Ecological Sciences Indian Institute of Science Bengaluru India
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Hurtado LA, Rigg CA, Calzada JE, Dutary S, Bernal D, Koo SI, Chaves LF. Population Dynamics of Anopheles albimanus (Diptera: Culicidae) at Ipetí-Guna, a Village in a Region Targeted for Malaria Elimination in Panamá. INSECTS 2018; 9:insects9040164. [PMID: 30453469 PMCID: PMC6316695 DOI: 10.3390/insects9040164] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 07/16/2018] [Accepted: 07/17/2018] [Indexed: 11/20/2022]
Abstract
Anopheles albimanus Wiedemann is a major malaria vector in Mesoamerica and the Caribbean whose population dynamics, in response to changing environments, has been relatively poorly studied. Here, we present monthly adult and larvae data collected from May 2016 to December 2017 in Ipetí-Guna, a village within an area targeted for malaria elimination in the República de Panamá. During the study period we collected a total of 1678 Anopheles spp. mosquitoes (1602 adults and 76 larvae). Over 95% of the collected Anopheles spp. mosquitoes were An. albimanus. Using time series analysis techniques, we found that population dynamics of larvae and adults were not significantly correlated with each other at any time lag, though correlations were highest at one month lag between larvae and adults and four months lag between adults and larvae. Larvae population dynamics had cycles of three months and were sensitive to changes in temperature with 5 months lag, while adult abundance was correlated with itself (1 month lag) and with the normalized difference vegetation index (NDVI) with three months lag. A key observation from our study is the absence of both larvae and adults of An. albimanus between January and April from environments associated with Guna population’s daily activities, which suggests this time window could be the best time to implement elimination campaigns aimed at clearing Plasmodium spp. parasites from Guna populations using, for example, mass drug administration.
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Affiliation(s)
- Lisbeth Amarilis Hurtado
- Departamento de Análisis Epidemiológico y Bioestadísticas, Instituto Conmemorativo Gorgas de Estudios de la Salud, Apartado Postal 0816-02593, Panamá, Republic of Panama.
| | - Chystrie A Rigg
- Departamento de Investigación en Parasitología, Instituto Conmemorativo Gorgas de Estudios de la Salud, Apartado Postal 0816-02593, Panamá, Republic of Panama.
| | - José E Calzada
- Departamento de Investigación en Parasitología, Instituto Conmemorativo Gorgas de Estudios de la Salud, Apartado Postal 0816-02593, Panamá, Republic of Panama.
| | - Sahir Dutary
- Departamento de Análisis Epidemiológico y Bioestadísticas, Instituto Conmemorativo Gorgas de Estudios de la Salud, Apartado Postal 0816-02593, Panamá, Republic of Panama.
| | - Damaris Bernal
- Departamento de Investigación en Entomología Médica, Instituto Conmemorativo Gorgas de Estudios de la Salud, Apartado Postal 0816-02593, Panamá, Republic of Panama.
| | - Susana Isabel Koo
- Departamento de Investigación en Entomología Médica, Instituto Conmemorativo Gorgas de Estudios de la Salud, Apartado Postal 0816-02593, Panamá, Republic of Panama.
| | - Luis Fernando Chaves
- Instituto Costarricense de Investigación y Enseñanza en Nutrición y Salud (INCIENSA), Apartado Postal 4-2250, Tres Ríos, Cartago, Costa Rica.
- Programa de Investigación en Enfermedades Tropicales (PIET), Escuela de Medicina Veterinaria, Universidad Nacional, Apartado Postal 304-3000, Heredia, Costa Rica.
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Hutter SE, Käsbohrer A, González SLF, León B, Brugger K, Baldi M, Mario Romero L, Gao Y, Chaves LF. Assessing changing weather and the El Niño Southern Oscillation impacts on cattle rabies outbreaks and mortality in Costa Rica (1985-2016). BMC Vet Res 2018; 14:285. [PMID: 30223839 PMCID: PMC6142330 DOI: 10.1186/s12917-018-1588-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 08/21/2018] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Rabies is a major zoonotic disease affecting humans, domestic and wildlife mammals. Cattle are the most important domestic animals impacted by rabies virus in the New World, leading to thousands of cattle deaths per year and eliciting large economic losses. In the New World, virus transmission in cattle is primarily associated with Desmodus rotundus, the common vampire bat. This study analyses the association of weather fluctuations and the El Niño Southern Oscillation (ENSO), with the occurrence and magnitude, in terms of associated mortality, of cattle rabies outbreaks. Data from the 100 cattle rabies outbreaks recorded between 1985 and 2016 in Costa Rica were analyzed. Periodograms for time series of rabies outbreaks and the El Niño 4 index were estimated. Seasonality was studied using a seasonal boxplot. The association between epidemiological and climatic time series was studied via cross wavelet coherence analysis. Retrospective space-time scan cluster analyses were also performed. Finally, seasonal autoregressive time series models were fitted to study linear associations between monthly number of outbreaks, monthly mortality rates and the El Niño 4 index, temperature, and rainfall. RESULTS Large rabies mortality occurred towards the Atlantic basin of the country. Outbreak occurrence and size were not directly associated with ENSO, but were sensitive to weather variables impacted by ENSO. Both, ENSO phases and rabies outbreaks, showed a similar 5 year period in their oscillations. Cattle rabies mortality and outbreak occurrence increased with temperature, whereas outbreak occurrence decreased with rainfall. These results suggest that special weather conditions might favor the occurrence of cattle rabies outbreaks. CONCLUSIONS Further efforts are necessary to articulate the mechanisms underpinning the association between weather changes and cattle rabies outbreaks. One hypothesis is that exacerbation of cattle rabies outbreaks might be mediated by impacts of weather conditions on common vampire bat movement and access to food resources on its natural habitats. Further eco-epidemiological field studies could help to understand rabies virus transmission ecology, and to propose sound interventions to control this major veterinary public health problem.
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Affiliation(s)
- Sabine E. Hutter
- Institute of Veterinary Public Health, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Veterinärplatz 1, 1210 Wien, Austria
| | - Annemarie Käsbohrer
- Institute of Veterinary Public Health, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Veterinärplatz 1, 1210 Wien, Austria
| | | | - Bernal León
- Servicio Nacional de Salud Animal (SENASA), Heredia, Costa Rica
| | - Katharina Brugger
- Institute of Veterinary Public Health, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Veterinärplatz 1, 1210 Wien, Austria
| | - Mario Baldi
- Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Austria
| | - L. Mario Romero
- Centro de Investigación en Enfermedades Tropicales (CIET), Universidad de Costa Rica, San Pedro de Montes de Oca, Costa Rica
| | - Yan Gao
- Centro de Investigaciones en Geografía Ambiental, Universidad Nacional Autónoma de México, 58190 Morelia, Michoacán Mexico
| | - Luis Fernando Chaves
- Instituto Costarricense de Investigación y Enseñanza en Nutrición y Salud, Apartado Postal 4-2250, Tres Ríos, Cartago, Costa Rica
- Programa de Investigación en Enfermedades Tropicales (PIET), Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
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Hurtado LA, Calzada JE, Rigg CA, Castillo M, Chaves LF. Climatic fluctuations and malaria transmission dynamics, prior to elimination, in Guna Yala, República de Panamá. Malar J 2018; 17:85. [PMID: 29463259 PMCID: PMC5819664 DOI: 10.1186/s12936-018-2235-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 02/13/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria has historically been entrenched in indigenous populations of the República de Panamá. This scenario occurs despite the fact that successful methods for malaria elimination were developed during the creation of the Panamá Canal. Today, most malaria cases in the República de Panamá affect the Gunas, an indigenous group, which mainly live in autonomous regions of eastern Panamá. Over recent decades several malaria outbreaks have affected the Gunas, and one hypothesis is that such outbreaks could have been exacerbated by climate change, especially by anomalous weather patterns driven by the EL Niño Southern Oscillation (ENSO). RESULTS Monthly malaria cases in Guna Yala (1998-2016) were autocorrelated up to 2 months of lag, likely reflecting parasite transmission cycles between humans and mosquitoes, and cyclically for periods of 4 months that might reflect relapses of Plasmodium vivax, the dominant malaria parasite transmitted in Panamá. Moreover, malaria case number was positively associated (P < 0.05) with rainfall (7 months of lag), and negatively with the El Niño 4 index (15 months of lag) and the Normalized Difference Vegetation Index, NDVI (8 months of lag), the sign and magnitude of these associations likely related to the impacts of weather patterns and vegetation on the ecology of Anopheles albimanus, the main malaria vector in Guna Yala. Interannual cycles, of approximately 4-year periods, in monthly malaria case numbers were associated with the El Niño 4 index, a climatic index associated with weather and vegetation dynamics in Guna Yala at seasonal and interannual time scales. CONCLUSION The results showed that ENSO, rainfall and NDVI were associated with the number of malaria cases in Guna Yala during the study period. These results highlight the vulnerability of Guna populations to malaria, an infection sensitive to climate change, and call for further studies about weather impacts on malaria vector ecology, as well as the association of malaria vectors with Gunas paying attention to their socio-economic conditions of poverty and cultural differences as an ethnic minority.
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Affiliation(s)
- Lisbeth Amarilis Hurtado
- Unidad de Análisis Epidemiológico y Bioestadísticas, Instituto Commemorativo Gorgas de Estudios de la Salud, Panamá, República de Panamá
| | - José E Calzada
- Departamento de Investigación en Parasitología, Instituto Commemorativo Gorgas de Estudios de la Salud, Panamá, República de Panamá
| | - Chystrie A Rigg
- Departamento de Investigación en Parasitología, Instituto Commemorativo Gorgas de Estudios de la Salud, Panamá, República de Panamá
| | - Milagros Castillo
- Unidad de Análisis Epidemiológico y Bioestadísticas, Instituto Commemorativo Gorgas de Estudios de la Salud, Panamá, República de Panamá
| | - Luis Fernando Chaves
- Instituto Costarricense de Investigación y Enseñanza en Nutrición y Salud (INCIENSA), Apartado 4-2250, Tres Ríos, Cartago, Costa Rica.
- Programa de Investigación en Enfermedades Tropicales (PIET), Escuela de Medicina Veterinaria, Universidad Nacional, Apartado Postal 304-3000, Heredia, Costa Rica.
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Chuang TW, Soble A, Ntshalintshali N, Mkhonta N, Seyama E, Mthethwa S, Pindolia D, Kunene S. Assessment of climate-driven variations in malaria incidence in Swaziland: toward malaria elimination. Malar J 2017; 16:232. [PMID: 28571572 PMCID: PMC5455096 DOI: 10.1186/s12936-017-1874-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 05/24/2017] [Indexed: 12/01/2022] Open
Abstract
Background Swaziland aims to eliminate malaria by 2020. However, imported cases from neighbouring endemic countries continue to sustain local parasite reservoirs and initiate transmission. As certain weather and climatic conditions may trigger or intensify malaria outbreaks, identification of areas prone to these conditions may aid decision-makers in deploying targeted malaria interventions more effectively. Methods Malaria case-surveillance data for Swaziland were provided by Swaziland’s National Malaria Control Programme. Climate data were derived from local weather stations and remote sensing images. Climate parameters and malaria cases between 2001 and 2015 were then analysed using seasonal autoregressive integrated moving average models and distributed lag non-linear models (DLNM). Results The incidence of malaria in Swaziland increased between 2005 and 2010, especially in the Lubombo and Hhohho regions. A time-series analysis indicated that warmer temperatures and higher precipitation in the Lubombo and Hhohho administrative regions are conducive to malaria transmission. DLNM showed that the risk of malaria increased in Lubombo when the maximum temperature was above 30 °C or monthly precipitation was above 5 in. In Hhohho, the minimum temperature remaining above 15 °C or precipitation being greater than 10 in. might be associated with malaria transmission. Conclusions This study provides a preliminary assessment of the impact of short-term climate variations on malaria transmission in Swaziland. The geographic separation of imported and locally acquired malaria, as well as population behaviour, highlight the varying modes of transmission, part of which may be relevant to climate conditions. Thus, the impact of changing climate conditions should be noted as Swaziland moves toward malaria elimination. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1874-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ting-Wu Chuang
- Department of Molecular Parasitology and Tropical Diseases, School of Medicine, College of Medicine, Taipei Medical University, No. 250, Wuxing St. Sinyi District, Taipei, 100, Taiwan.
| | - Adam Soble
- Clinton Health Access Initiative, Manzini, Swaziland
| | | | - Nomcebo Mkhonta
- National Malaria Control Programme, Ministry of Health, Manzini, Swaziland
| | - Eric Seyama
- Swaziland Meteorological Service, Mbabane, Swaziland
| | - Steven Mthethwa
- National Malaria Control Programme, Ministry of Health, Manzini, Swaziland
| | | | - Simon Kunene
- National Malaria Control Programme, Ministry of Health, Manzini, Swaziland
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Lockaby G, Noori N, Morse W, Zipperer W, Kalin L, Governo R, Sawant R, Ricker M. Climatic, ecological, and socioeconomic factors associated with West Nile virus incidence in Atlanta, Georgia, U.S.A. JOURNAL OF VECTOR ECOLOGY : JOURNAL OF THE SOCIETY FOR VECTOR ECOLOGY 2016; 41:232-243. [PMID: 27860011 DOI: 10.1111/jvec.12218] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 06/17/2016] [Indexed: 05/14/2023]
Abstract
The integrated effects of the many risk factors associated with West Nile virus (WNV) incidence are complex and not well understood. We studied an array of risk factors in and around Atlanta, GA, that have been shown to be linked with WNV in other locations. This array was comprehensive and included climate and meteorological metrics, vegetation characteristics, land use / land cover analyses, and socioeconomic factors. Data on mosquito abundance and WNV mosquito infection rates were obtained for 58 sites and covered 2009-2011, a period following the combined storm water - sewer overflow remediation in that city. Risk factors were compared to mosquito abundance and the WNV vector index (VI) using regression analyses individually and in combination. Lagged climate variables, including soil moisture and temperature, were significantly correlated (positively) with vector index as were forest patch size and percent pine composition of patches (both negatively). Socioeconomic factors that were most highly correlated (positively) with the VI included the proportion of low income households and homes built before 1960 and housing density. The model selected through stepwise regression that related risk factors to the VI included (in the order of decreasing influence) proportion of houses built before 1960, percent of pine in patches, and proportion of low income households.
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Affiliation(s)
- Graeme Lockaby
- Auburn University, School of Forestry and Wildlife Sciences, Auburn, AL, U.S.A
| | - Navideh Noori
- University of Georgia, Odum School of Ecology, Athens, GA, U.S.A
| | - Wayde Morse
- Auburn University, School of Forestry and Wildlife Sciences, Auburn, AL, U.S.A
| | - Wayne Zipperer
- USDA Forest Service Southern Research Station, Gainesville, FL, U.S.A
| | - Latif Kalin
- Auburn University, School of Forestry and Wildlife Sciences, Auburn, AL, U.S.A
| | - Robin Governo
- Auburn University, School of Forestry and Wildlife Sciences, Auburn, AL, U.S.A
| | - Rajesh Sawant
- Auburn University, School of Forestry and Wildlife Sciences, Auburn, AL, U.S.A
| | - Matthew Ricker
- University of Pennsylvania, Department of Environmental, Geographical, and Geologic Sciences, Bloomsburg, PA, U.S.A
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Onyango EA, Sahin O, Awiti A, Chu C, Mackey B. An integrated risk and vulnerability assessment framework for climate change and malaria transmission in East Africa. Malar J 2016; 15:551. [PMID: 27835976 PMCID: PMC5105305 DOI: 10.1186/s12936-016-1600-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 11/04/2016] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Malaria is one of the key research concerns in climate change-health relationships. Numerous risk assessments and modelling studies provide evidence that the transmission range of malaria will expand with rising temperatures, adversely impacting on vulnerable communities in the East African highlands. While there exist multiple lines of evidence for the influence of climate change on malaria transmission, there is insufficient understanding of the complex and interdependent factors that determine the risk and vulnerability of human populations at the community level. Moreover, existing studies have had limited focus on the nature of the impacts on vulnerable communities or how well they are prepared to cope. In order to address these gaps, a systems approach was used to present an integrated risk and vulnerability assessment framework for studies of community level risk and vulnerability to malaria due to climate change. RESULTS Drawing upon published literature on existing frameworks, a systems approach was applied to characterize the factors influencing the interactions between climate change and malaria transmission. This involved structural analysis to determine influential, relay, dependent and autonomous variables in order to construct a detailed causal loop conceptual model that illustrates the relationships among key variables. An integrated assessment framework that considers indicators of both biophysical and social vulnerability was proposed based on the conceptual model. CONCLUSIONS A major conclusion was that this integrated assessment framework can be implemented using Bayesian Belief Networks, and applied at a community level using both quantitative and qualitative methods with stakeholder engagement. The approach enables a robust assessment of community level risk and vulnerability to malaria, along with contextually relevant and targeted adaptation strategies for dealing with malaria transmission that incorporate both scientific and community perspectives.
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Affiliation(s)
- Esther Achieng Onyango
- Centre for Environment and Population Health, Griffith University, School of Environment, 170 Kessels Road, Nathan, 4111 Australia
| | - Oz Sahin
- School of Engineering, Griffith University, Gold Coast, 4222 Australia
- Griffith Climate Change Response Program, Griffith University, Gold Coast, 4222 Australia
| | - Alex Awiti
- East African Institute, Aga Khan University East Africa, 2nd Parklands Avenue, Nairobi, 00100 Kenya
| | - Cordia Chu
- Centre for Environment and Population Health, Griffith University, School of Environment, 170 Kessels Road, Nathan, 4111 Australia
| | - Brendan Mackey
- Griffith Climate Change Response Program, Griffith University, Gold Coast, 4222 Australia
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Ruybal JE, Kramer LD, Kilpatrick AM. Geographic variation in the response of Culex pipiens life history traits to temperature. Parasit Vectors 2016; 9:116. [PMID: 26928181 PMCID: PMC4772444 DOI: 10.1186/s13071-016-1402-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 02/22/2016] [Indexed: 11/17/2022] Open
Abstract
Background Climate change is predicted to alter the transmission of many vector-borne pathogens. The quantitative impact of climate change is usually estimated by measuring the temperature-performance relationships for a single population of vectors, and then mapping this relationship across a range of temperatures or locations. However, life history traits of different populations often differ significantly. Specifically, performance across a range of temperatures is likely to vary due to local adaptation to temperature and other factors. This variation can cause spatial variation in pathogen transmission and will influence the impact of climate change on the transmission of vector-borne pathogens. Methods We quantified variation in life history traits for four populations of Culex pipiens (Linnaeus) mosquitoes. The populations were distributed along altitudinal and latitudinal gradients in the eastern United States that spanned ~3 °C in mean summer temperature, which is similar to the magnitude of global warming expected in the next 3–5 decades. We measured larval and adult survival, development rate, and biting rate at six temperatures between 16 and 35 °C, in a common garden experiment. Results Temperature had strong and consistent non-linear effects on all four life history traits for all four populations. Adult female development time decreased monotonically with increasing temperature, with the largest decrease at cold temperatures. Daily juvenile and adult female survival also decreased with increasing temperature, but the largest decrease occurred at higher temperatures. There was significant among-population variation in the thermal response curves for the four life history traits across the four populations, with larval survival, adult survival, and development rate varying up to 45, 79, and 84 % among populations, respectively. However, variation was not correlated with local temperatures and thus did not support the local thermal adaptation hypothesis. Conclusion These results suggest that the impact of climate change on vector-borne disease will be more variable than previous predictions, and our data provide an estimate of this uncertainty. In addition, the variation among populations that we observed will shape the response of vectors to changing climates. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1402-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jordan E Ruybal
- Department Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95064, USA.
| | - Laura D Kramer
- New York State Department of Health, Wadsworth Center, Slingerlands, NY, 12159, USA. .,State University of New York at Albany, Albany, NY, USA.
| | - A Marm Kilpatrick
- Department Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95064, USA.
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Karuri SW, Snow RW. Forecasting paediatric malaria admissions on the Kenya Coast using rainfall. Glob Health Action 2016; 9:29876. [PMID: 26842613 PMCID: PMC4740093 DOI: 10.3402/gha.v9.29876] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 11/29/2015] [Accepted: 12/29/2015] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Malaria is a vector-borne disease which, despite recent scaled-up efforts to achieve control in Africa, continues to pose a major threat to child survival. The disease is caused by the protozoan parasite Plasmodium and requires mosquitoes and humans for transmission. Rainfall is a major factor in seasonal and secular patterns of malaria transmission along the East African coast. OBJECTIVE The goal of the study was to develop a model to reliably forecast incidences of paediatric malaria admissions to Kilifi District Hospital (KDH). DESIGN In this article, we apply several statistical models to look at the temporal association between monthly paediatric malaria hospital admissions, rainfall, and Indian Ocean sea surface temperatures. Trend and seasonally adjusted, marginal and multivariate, time-series models for hospital admissions were applied to a unique data set to examine the role of climate, seasonality, and long-term anomalies in predicting malaria hospital admission rates and whether these might become more or less predictable with increasing vector control. RESULTS The proportion of paediatric admissions to KDH that have malaria as a cause of admission can be forecast by a model which depends on the proportion of malaria admissions in the previous 2 months. This model is improved by incorporating either the previous month's Indian Ocean Dipole information or the previous 2 months' rainfall. CONCLUSIONS Surveillance data can help build time-series prediction models which can be used to anticipate seasonal variations in clinical burdens of malaria in stable transmission areas and aid the timing of malaria vector control.
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Affiliation(s)
- Stella Wanjugu Karuri
- Spatial Health Metrics Group, Kenya Medical Research Institute-Wellcome Trust Research Programme, Nairobi, Kenya;
| | - Robert W Snow
- Spatial Health Metrics Group, Kenya Medical Research Institute-Wellcome Trust Research Programme, Nairobi, Kenya.,Nuffield Department of Clinical Medicine, Centre for Tropical Medicine & Global Health, University of Oxford, Oxford, United Kingdom
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Cooke MK, Kahindi SC, Oriango RM, Owaga C, Ayoma E, Mabuka D, Nyangau D, Abel L, Atieno E, Awuor S, Drakeley C, Cox J, Stevenson J. 'A bite before bed': exposure to malaria vectors outside the times of net use in the highlands of western Kenya. Malar J 2015; 14:259. [PMID: 26109384 PMCID: PMC4479228 DOI: 10.1186/s12936-015-0766-4] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 06/06/2015] [Indexed: 12/25/2022] Open
Abstract
Background The human population in the highlands of Nyanza Province, western Kenya, is subject to sporadic epidemics of Plasmodium falciparum. Indoor residual spraying (IRS) and long-lasting insecticide treated nets (LLINs) are used widely in this area. These interventions are most effective when Anopheles rest and feed indoors and when biting occurs at times when individuals use LLINs. It is therefore important to test the current assumption of vector feeding preferences, and late night feeding times, in order to estimate the extent to which LLINs protect the inhabitants from vector bites. Methods Mosquito collections were made for six consecutive nights each month between June 2011 and May 2012. CDC light-traps were set next to occupied LLINs inside and outside randomly selected houses and emptied hourly. The net usage of residents, their hours of house entry and exit and times of sleeping were recorded and the individual hourly exposure to vectors indoors and outdoors was calculated. Using these data, the true protective efficacy of nets (P*), for this population was estimated, and compared between genders, age groups and from month to month. Results Primary vector species (Anopheles funestus s.l. and Anopheles arabiensis) were more likely to feed indoors but the secondary vector Anopheles coustani demonstrated exophagic behaviour (p < 0.05). A rise in vector biting activity was recorded at 19:30 outdoors and 18:30 indoors. Individuals using LLINs experienced a moderate reduction in their overall exposure to malaria vectors from 1.3 to 0.47 bites per night. The P* for the population over the study period was calculated as 51% and varied significantly with age and season (p < 0.01). Conclusions In the present study, LLINs offered the local population partial protection against malaria vector bites. It is likely that P* would be estimated to be greater if the overall suppression of the local vector population due to widespread community net use could be taken into account. However, the overlap of early biting habit of vectors and human activity in this region indicates that additional methods of vector control are required to limit transmission. Regular surveillance of both vector behaviour and domestic human-behaviour patterns would assist the planning of future control interventions in this region. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0766-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mary K Cooke
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
| | - Sam C Kahindi
- Kenya Medical Research Institute Centre for Global Health Research/Centers for Disease Control and Prevention, Kisumu, Kenya.
| | - Robin M Oriango
- Kenya Medical Research Institute Centre for Global Health Research/Centers for Disease Control and Prevention, Kisumu, Kenya.
| | - Chrispin Owaga
- Kenya Medical Research Institute Centre for Global Health Research/Centers for Disease Control and Prevention, Kisumu, Kenya.
| | - Elizabeth Ayoma
- Kenya Medical Research Institute Centre for Global Health Research/Centers for Disease Control and Prevention, Kisumu, Kenya.
| | - Danspaid Mabuka
- Kenya Medical Research Institute Centre for Global Health Research/Centers for Disease Control and Prevention, Kisumu, Kenya.
| | - Dennis Nyangau
- Kenya Medical Research Institute Centre for Global Health Research/Centers for Disease Control and Prevention, Kisumu, Kenya.
| | - Lucy Abel
- Kenya Medical Research Institute Centre for Global Health Research/Centers for Disease Control and Prevention, Kisumu, Kenya.
| | - Elizabeth Atieno
- Kenya Medical Research Institute Centre for Global Health Research/Centers for Disease Control and Prevention, Kisumu, Kenya.
| | - Stephen Awuor
- Kenya Medical Research Institute Centre for Global Health Research/Centers for Disease Control and Prevention, Kisumu, Kenya.
| | - Chris Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
| | - Jonathan Cox
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
| | - Jennifer Stevenson
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK. .,Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health/Macha Research Trust, Choma, Zambia.
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Hurtado LA, Cáceres L, Chaves LF, Calzada JE. When climate change couples social neglect: malaria dynamics in Panamá. Emerg Microbes Infect 2014; 3:e27. [PMID: 26038518 PMCID: PMC4008768 DOI: 10.1038/emi.2014.27] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 02/28/2014] [Accepted: 03/03/2014] [Indexed: 11/09/2022]
Abstract
A major challenge of infectious disease elimination is the need to interrupt pathogen transmission across all vulnerable populations. Ethnic minorities are among the key vulnerable groups deserving special attention in disease elimination initiatives, especially because their lifestyle might be intrinsically linked to locations with high transmission risk. There has been a renewed interest in malaria elimination, which has ignited a quest to understand factors necessary for sustainable malaria elimination, highlighting the need for diverse approaches to address epidemiological heterogeneity across malaria transmission settings. An analysis of malaria incidence among the Guna Amerindians of Panamá over the last 34 years showed that this ethnic minority was highly vulnerable to changes that were assumed to not impact malaria transmission. Epidemic outbreaks were linked with El Niño Southern Oscillations and were sensitive to political instability and policy changes that did not ensure adequate attention to the malaria control needs of the Gunas. Our results illustrate how the neglect of minorities poses a threat to the sustainable control and eventual elimination of malaria in Central America and other areas where ethnic minorities do not share the benefits of malaria control strategies intended for dominant ethnic groups.
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Affiliation(s)
- Lisbeth Amarilis Hurtado
- Departamento de Parasitología, Instituto Conmemorativo Gorgas de Estudios de la Salud (ICGES), Apartado Postal No. 0816-02593 , Ciudad de Panamá, República de Panamá
| | - Lorenzo Cáceres
- Departamento de Entomología Médica, Instituto Conmemorativo Gorgas de Estudios de la Salud (ICGES), Apartado Postal No. 0816-02593 , Ciudad de Panamá, República de Panamá
| | - Luis Fernando Chaves
- Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto , Nagasaki 852-8523, Japan ; Programa de Investigación en Enfermedades Tropicales (PIET), Escuela de Medicina Veterinaria, Universidad Nacional, Apartado Postal No. 304-3000 , Heredia, Costa Rica
| | - José E Calzada
- Departamento de Parasitología, Instituto Conmemorativo Gorgas de Estudios de la Salud (ICGES), Apartado Postal No. 0816-02593 , Ciudad de Panamá, República de Panamá
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Baum E, Badu K, Molina DM, Liang X, Felgner PL, Yan G. Protein microarray analysis of antibody responses to Plasmodium falciparum in western Kenyan highland sites with differing transmission levels. PLoS One 2013; 8:e82246. [PMID: 24312649 PMCID: PMC3846730 DOI: 10.1371/journal.pone.0082246] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 10/22/2013] [Indexed: 01/01/2023] Open
Abstract
Malaria represents a major public health problem in Africa. In the East African highlands, the high-altitude areas were previously considered too cold to support vector population and parasite transmission, rendering the region particularly prone to epidemic malaria due to the lack of protective immunity of the population. Since the 1980’s, frequent malaria epidemics have been reported and these successive outbreaks may have generated some immunity against Plasmodium falciparum amongst the highland residents. Serological studies reveal indirect evidence of human exposure to the parasite, and can reliably assess prevalence of exposure and transmission intensity in an endemic area. However, the vast majority of serological studies of malaria have been, hereto, limited to a small number of the parasite’s antigens. We surveyed and compared the antibody response profiles of age-stratified sera from residents of two endemic areas in the western Kenyan highlands with differing malaria transmission intensities, during two distinct seasons, against 854 polypeptides of P. falciparum using high-throughput proteomic microarray technology. We identified 107 proteins as serum antibody targets, which were then characterized for their gene ontology biological process and cellular component of the parasite, and showed significant enrichment for categories related to immune evasion, pathogenesis and expression on the host’s cell and parasite’s surface. Additionally, we calculated age-fitted annual seroconversion rates for the immunogenic proteins, and contrasted the age-dependent antibody acquisition for those antigens between the two sampling sites. We observed highly immunogenic antigens that produce stable antibody responses from early age in both sites, as well as less immunogenic proteins that require repeated exposure for stable responses to develop and produce different seroconversion rates between sites. We propose that a combination of highly and less immunogenic proteins could be used in serological surveys to detect differences in malaria transmission levels, distinguishing sites of unstable and stable transmission.
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Affiliation(s)
- Elisabeth Baum
- Department of Medicine, Division of Infectious Diseases, University of California Irvine, Irvine, California, United States of America
- * E-mail:
| | - Kingsley Badu
- Department of Immunology, Noguchi Memorial Institute for Medical Sciences, College of Health Science, University of Ghana, Accra, Ghana
| | - Douglas M. Molina
- Antigen Discovery Inc., Irvine, California, United States of America
| | - Xiaowu Liang
- Antigen Discovery Inc., Irvine, California, United States of America
| | - Philip L. Felgner
- Department of Medicine, Division of Infectious Diseases, University of California Irvine, Irvine, California, United States of America
| | - Guiyun Yan
- Program in Public Health, University of California Irvine, Irvine, California, United States of America
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Abstract
Emerging vector-borne diseases are an important issue in global health. Many vector-borne pathogens have appeared in new regions in the past two decades, while many endemic diseases have increased in incidence. Although introductions and emergence of endemic pathogens are often considered to be distinct processes, many endemic pathogens are actually spreading at a local scale coincident with habitat change. We draw attention to key differences between dynamics and disease burden that result from increased pathogen transmission after habitat change and after introduction into new regions. Local emergence is commonly driven by changes in human factors as much as by enhanced enzootic cycles, whereas pathogen invasion results from anthropogenic trade and travel where and when conditions (eg, hosts, vectors, and climate) are suitable for a pathogen. Once a pathogen is established, ecological factors related to vector characteristics can shape the evolutionary selective pressure and result in increased use of people as transmission hosts. We describe challenges inherent in the control of vector-borne zoonotic diseases and some emerging non-traditional strategies that could be effective in the long term.
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Affiliation(s)
- A Marm Kilpatrick
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA.
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Landoh ED, Tchamdja P, Saka B, Tint KS, Gitta SN, Wasswa P, Christiaan DJ. Morbidity and mortality due to malaria in Est Mono district, Togo, from 2005 to 2010: a times series analysis. Malar J 2012; 11:389. [PMID: 23173765 PMCID: PMC3519571 DOI: 10.1186/1475-2875-11-389] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 11/21/2012] [Indexed: 11/18/2022] Open
Abstract
Background In 2004, Togo adopted a regional strategy for malaria control that made use of insecticide-treated nets (ITNs), followed by the use of rapid diagnostic tests (RDTs), artemisinin-based combination therapy (ACT). Community health workers (CHWs) became involved in 2007. In 2010, the impact of the implementation of these new malaria control strategies had not yet been evaluated. This study sought to assess the trends of malaria incidence and mortality due to malaria in Est Mono district from 2005 to 2010. Methods Secondary data on confirmed and suspected malaria cases reported by health facilities from 2005 to 2010 were obtained from the district health information system. Rainfall and temperature data were provided by the national Department of Meteorology. Chi square test or independent student’s t-test were used to compare trends of variables at a 95% confidence interval. An interrupted time series analysis was performed to assess the effect of meteorological factors and the use of ACT and CHWs on morbidity and mortality due to malaria. Results From January 2005 to December 2010, 114,654 malaria cases (annual mean 19,109 ± 6,622) were reported with an increase of all malaria cases from 10,299 in 2005 to 26,678 cases in 2010 (p<0.001). Of the 114,654 malaria cases 52,539 (45.8%) were confirmed cases. The prevalence of confirmed malaria cases increased from 23.1 per 1,000 in 2005 to 257.5 per 1,000 population in 2010 (p <0.001). The mortality rate decreased from 7.2 per 10,000 in 2005 to 3.6 per 10,000 in 2010 (p <0.001), with a significant reduction of 43.9% of annual number of death due to malaria. Rainfall (β-coefficient = 1.6; p = 0.05) and number of CHWs trained (β-coefficient = 6.8; p = 0.002) were found to be positively correlated with malaria prevalence. Conclusion This study showed an increase of malaria prevalence despite the implementation of the use of ACT and CHW strategies. Multicentre data analysis over longer periods should be carried out in similar settings to assess the impact of malaria control strategies on the burden of the disease. Integrated malaria vector control management should be implemented in Togo to reduce malaria transmission.
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Affiliation(s)
- Essoya D Landoh
- Division de l'Epidémiologie, Ministère de la Santé du Togo, BP: 1396, Lomé, Togo.
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Himeidan YE, Kweka EJ. Malaria in East African highlands during the past 30 years: impact of environmental changes. Front Physiol 2012; 3:315. [PMID: 22934065 PMCID: PMC3429085 DOI: 10.3389/fphys.2012.00315] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Accepted: 07/18/2012] [Indexed: 11/29/2022] Open
Abstract
East African highlands are one of the most populated regions in Africa. The population densities in the highlands ranged between 158 persons/km2 in Ethiopia and 410 persons/km2 in Rwanda. According to the United Nations Population Fund, the region has the world's highest population growth rate. These factors are likely behind the high rates of poverty among the populations. As there were no employment opportunities other than agricultural, this demographic pressure of poor populations have included in an extensive unprecedented land use and land cover changes such as modification of bushland, woodland, and grassland on hillsides to farmland and transformation of papyrus swamps in valley bottoms to dairy pastures and cropland and changing of fallows on hillsides from short or seasonal to longer or perennial. Areas harvested for food crops were therefore increased by more than 100% in most of the highlands. The lost of forest areas, mainly due to subsistence agriculture, between 1990 and 2010 ranged between 8000 ha in Rwanda and 2,838,000 ha in Ethiopia. These unmitigated environmental changes in the highlands led to rise temperature and optimizing the spread and survival of malaria vectors and development of malaria parasites. Malaria in highlands was initially governed by low ambient temperature, trend of malaria transmission was therefore increased and several epidemics were observed in late 1980s and early 2000s. Although, malaria is decreasing through intensified interventions since mid 2000s onwards, these environmental changes might expose population in the highlands of east Africa to an increase risk of malaria and its epidemic particularly if the current interventions are not sustained.
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Affiliation(s)
- Yousif E Himeidan
- Entomology Unit, Faculty of Agriculture and Natural Resources, University of Kassala New Halfa, Sudan
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Ramasamy R, Surendran SN. Global climate change and its potential impact on disease transmission by salinity-tolerant mosquito vectors in coastal zones. Front Physiol 2012; 3:198. [PMID: 22723781 PMCID: PMC3377959 DOI: 10.3389/fphys.2012.00198] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 05/22/2012] [Indexed: 11/19/2022] Open
Abstract
Global climate change can potentially increase the transmission of mosquito vector-borne diseases such as malaria, lymphatic filariasis, and dengue in many parts of the world. These predictions are based on the effects of changing temperature, rainfall, and humidity on mosquito breeding and survival, the more rapid development of ingested pathogens in mosquitoes and the more frequent blood feeds at moderately higher ambient temperatures. An expansion of saline and brackish water bodies (water with <0.5 ppt or parts per thousand, 0.5–30 ppt and >30 ppt salt are termed fresh, brackish, and saline respectively) will also take place as a result of global warming causing a rise in sea levels in coastal zones. Its possible impact on the transmission of mosquito-borne diseases has, however, not been adequately appreciated. The relevant impacts of global climate change on the transmission of mosquito-borne diseases in coastal zones are discussed with reference to the Ross–McDonald equation and modeling studies. Evidence is presented to show that an expansion of brackish water bodies in coastal zones can increase the densities of salinity-tolerant mosquitoes like Anopheles sundaicus and Culex sitiens, and lead to the adaptation of fresh water mosquito vectors like Anopheles culicifacies, Anopheles stephensi, Aedes aegypti, and Aedes albopictus to salinity. Rising sea levels may therefore act synergistically with global climate change to increase the transmission of mosquito-borne diseases in coastal zones. Greater attention therefore needs to be devoted to monitoring disease incidence and preimaginal development of vector mosquitoes in artificial and natural coastal brackish/saline habitats. It is important that national and international health agencies are aware of the increased risk of mosquito-borne diseases in coastal zones and develop preventive and mitigating strategies. Application of appropriate counter measures can greatly reduce the potential for increased coastal transmission of mosquito-borne diseases consequent to climate change and a rise in sea levels. It is proposed that the Jaffna peninsula in Sri Lanka may be a useful case study for the impact of rising sea levels on mosquito vectors in tropical coasts.
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Affiliation(s)
- Ranjan Ramasamy
- Institute of Health Sciences, Universiti Brunei Darussalam, Gadong Brunei Darussalam
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Hashizume M, Chaves LF, Minakawa N. Indian Ocean Dipole drives malaria resurgence in East African highlands. Sci Rep 2012; 2:269. [PMID: 22355781 PMCID: PMC3280600 DOI: 10.1038/srep00269] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Accepted: 01/20/2012] [Indexed: 11/17/2022] Open
Abstract
Malaria resurgence in African highlands in the 1990s has raised questions about the underlying drivers of the increase in disease incidence including the role of El-Niño-Southern Oscillation (ENSO). However, climatic anomalies other than the ENSO are clearly associated with malaria outbreaks in the highlands. Here we show that the Indian Ocean Dipole (IOD), a coupled ocean-atmosphere interaction in the Indian Ocean, affected highland malaria re-emergence. Using cross-wavelet coherence analysis, we found four-year long coherent cycles between the malaria time series and the dipole mode index (DMI) in the 1990s in three highland localities. Conversely, we found a less pronounced coherence between malaria and DMI in lowland localities. The highland/lowland contrast can be explained by the effects of mesoscale systems generated by Lake Victoria on its climate basin. Our results support the need to consider IOD as a driving force in the resurgence of malaria in the East African highlands.
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Affiliation(s)
- Masahiro Hashizume
- Institute of Tropical Medicine (NEKKEN) and the Global Center of Excellence program on Tropical and Emerging Infectious Diseases, Nagasaki University, Nagasaki, Japan
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Afrane YA, Githeko AK, Yan G. The ecology of Anopheles mosquitoes under climate change: case studies from the effects of deforestation in East African highlands. Ann N Y Acad Sci 2012; 1249:204-10. [PMID: 22320421 DOI: 10.1111/j.1749-6632.2011.06432.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Climate change is expected to lead to latitudinal and altitudinal temperature increases. High-elevation regions such as the highlands of Africa and those that have temperate climate are most likely to be affected. The highlands of Africa generally exhibit low ambient temperatures. This restricts the distribution of Anopheles mosquitoes, the vectors of malaria, filariasis, and O'nyong'nyong fever. The development and survival of larval and adult mosquitoes are temperature dependent, as are mosquito biting frequency and pathogen development rate. Given that various Anopheles species are adapted to different climatic conditions, changes in climate could lead to changes in species composition in an area that may change the dynamics of mosquito-borne disease transmission. It is important to consider the effect of climate change on rainfall, which is critical to the formation and persistence of mosquito breeding sites. In addition, environmental changes such as deforestation could increase local temperatures in the highlands; this could enhance the vectorial capacity of the Anopheles. These experimental data will be invaluable in facilitating the understanding of the impact of climate change on Anopheles.
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Affiliation(s)
- Yaw A Afrane
- Climate and Human Health Research Unit, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.
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