1
|
Wang Y, Chitnis N, Fairbanks EL. Optimizing malaria vector control in the Greater Mekong Subregion: a systematic review and mathematical modelling study to identify desirable intervention characteristics. Parasit Vectors 2024; 17:162. [PMID: 38553759 PMCID: PMC10981350 DOI: 10.1186/s13071-024-06234-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 03/04/2024] [Indexed: 04/01/2024] Open
Abstract
BACKGROUND In the Greater Mekong Subregion (GMS), new vector-control tools are needed to target mosquitoes that bite outside during the daytime and night-time to advance malaria elimination. METHODS We conducted systematic literature searches to generate a bionomic dataset of the main malaria vectors in the GMS, including human blood index (HBI), parity proportion, sac proportion (proportion with uncontracted ovary sacs, indicating the amount of time until they returned to host seeking after oviposition) and the resting period duration. We then performed global sensitivity analyses to assess the influence of bionomics and intervention characteristics on vectorial capacity. RESULTS Our review showed that Anopheles minimus, An. sinensis, An. maculatus and An. sundaicus display opportunistic blood-feeding behaviour, while An. dirus is more anthropophilic. Multivariate regression analysis indicated that environmental, climatic and sampling factors influence the proportion of parous mosquitoes, and resting duration varies seasonally. Sensitivity analysis highlighted HBI and parity proportion as the most influential bionomic parameters, followed by resting duration. Killing before feeding is always a desirable characteristic across all settings in the GMS. Disarming is also a desirable characteristic in settings with a low HBI. Repelling is only an effective strategy in settings with a low HBI and low parity proportion. Killing after feeding is only a desirable characteristic if the HBI and parity proportions in the setting are high. CONCLUSIONS Although in general adopting tools that kill before feeding would have the largest community-level effect on reducing outdoor transmission, other modes of action can be effective. Current tools in development which target outdoor biting mosquitoes should be implemented in different settings dependent on their characteristics.
Collapse
Affiliation(s)
- Yuqian Wang
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Kreuzstrasse 2, Allschwill, 4123, Basel, Switzerland
- University of Basel, Petersplatz 1, 4001, Basel, Switzerland
| | - Nakul Chitnis
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Kreuzstrasse 2, Allschwill, 4123, Basel, Switzerland
- University of Basel, Petersplatz 1, 4001, Basel, Switzerland
| | - Emma L Fairbanks
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Kreuzstrasse 2, Allschwill, 4123, Basel, Switzerland.
- University of Basel, Petersplatz 1, 4001, Basel, Switzerland.
| |
Collapse
|
2
|
Bationo C, Cissoko M, Katilé A, Sylla B, Ouédraogo A, Ouedraogo JB, Tougri G, Kompaoré SCB, Moiroux N, Gaudart J. Malaria in Burkina Faso: A comprehensive analysis of spatiotemporal distribution of incidence and environmental drivers, and implications for control strategies. PLoS One 2023; 18:e0290233. [PMID: 37703223 PMCID: PMC10499254 DOI: 10.1371/journal.pone.0290233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 08/05/2023] [Indexed: 09/15/2023] Open
Abstract
BACKGROUND The number of malaria cases worldwide has increased, with over 241 million cases and 69,000 more deaths in 2020 compared to 2019. Burkina Faso recorded over 11 million malaria cases in 2020, resulting in nearly 4,000 deaths. The overall incidence of malaria in Burkina Faso has been steadily increasing since 2016. This study investigates the spatiotemporal pattern and environmental and meteorological determinants of malaria incidence in Burkina Faso. METHODS We described the temporal dynamics of malaria cases by detecting the transmission periods and the evolution trend from 2013 to 2018. We detected hotspots using spatial scan statistics. We assessed different environmental zones through a hierarchical clustering and analyzed the environmental and climatic data to identify their association with malaria incidence at the national and at the district's levels through generalized additive models. We also assessed the time lag between malaria peaks onset and the rainfall at the district level. The environmental and climatic data were synthetized into indicators. RESULTS The study found that malaria incidence had a seasonal pattern, with high transmission occurring during the rainy seasons. We also found an increasing trend in the incidence. The highest-risk districts for malaria incidence were identified, with a significant expansion of high-risk areas from less than half of the districts in 2013-2014 to nearly 90% of the districts in 2017-2018. We identified three classes of health districts based on environmental and climatic data, with the northern, south-western, and western districts forming separate clusters. Additionally, we found that the time lag between malaria peaks onset and the rainfall at the district level varied from 7 weeks to 17 weeks with a median at 10 weeks. Environmental and climatic factors have been found to be associated with the number of cases both at global and districts levels. CONCLUSION The study provides important insights into the environmental and spatiotemporal patterns of malaria in Burkina Faso by assessing the spatio temporal dynamics of Malaria cases but also linking those dynamics to the environmental and climatic factors. The findings highlight the importance of targeted control strategies to reduce the burden of malaria in high-risk areas as we found that Malaria epidemiology is complex and linked to many factors that make some regions more at risk than others.
Collapse
Affiliation(s)
- Cédric Bationo
- Aix Marseille Univ, INSERM, IRD, ISSPAM, SESSTIM, UMR1252, Marseille, France
- MIVEGEC, Univ. Montpellier, CNRS, IRD, Montpellier, France
| | - Mady Cissoko
- Aix Marseille Univ, INSERM, IRD, ISSPAM, SESSTIM, UMR1252, Marseille, France
- Malaria Research and Training Center—Ogobara, Doumbo (MRTC-OD), FMOS-FAPH, Mali-NIAID-ICER, Université des Sciences, des Techniques et des Technologies de Bamako Mali, Bamako, Mali
| | - Abdoulaye Katilé
- Aix Marseille Univ, INSERM, IRD, ISSPAM, SESSTIM, UMR1252, Marseille, France
- Malaria Research and Training Center—Ogobara, Doumbo (MRTC-OD), FMOS-FAPH, Mali-NIAID-ICER, Université des Sciences, des Techniques et des Technologies de Bamako Mali, Bamako, Mali
| | - Bry Sylla
- Direction des Systèmes d’Information en Santé, Ministère de la Santé du Burkina Faso, Ouagadougou, Burkina Faso
| | - Ambroise Ouédraogo
- Programme National de Lutte contre le Paludisme, Ministère de la Santé du Burkina Faso, Ouagadougou, Burkina Faso
| | - Jean Baptiste Ouedraogo
- Programme National de Lutte contre le Paludisme, Ministère de la Santé du Burkina Faso, Ouagadougou, Burkina Faso
| | - Gauthier Tougri
- Programme National de Lutte contre le Paludisme, Ministère de la Santé du Burkina Faso, Ouagadougou, Burkina Faso
| | - Sidzabda C. B. Kompaoré
- Programme National de Lutte contre le Paludisme, Ministère de la Santé du Burkina Faso, Ouagadougou, Burkina Faso
| | - Nicolas Moiroux
- MIVEGEC, Univ. Montpellier, CNRS, IRD, Montpellier, France
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo Dioulasso, Burkina Faso
| | - Jean Gaudart
- Malaria Research and Training Center—Ogobara, Doumbo (MRTC-OD), FMOS-FAPH, Mali-NIAID-ICER, Université des Sciences, des Techniques et des Technologies de Bamako Mali, Bamako, Mali
- Aix Marseille Univ, INSERM, IRD, ISSPAM, SESSTIM, UMR1252, APHM, Hop Timone, BioSTIC, Biostatistic & ICT, Marseille, France
| |
Collapse
|
3
|
Ngonghala CN. The impact of temperature and decay in insecticide-treated net efficacy on malaria prevalence and control. Math Biosci 2023; 355:108936. [PMID: 36356891 DOI: 10.1016/j.mbs.2022.108936] [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: 07/12/2022] [Revised: 10/28/2022] [Accepted: 10/31/2022] [Indexed: 11/09/2022]
Abstract
Insecticide-treated nets (ITNs) have been useful and effective in mitigating the risk of malaria globally. However, due to misuse and normal/human-induced physical and chemical wear, the effectiveness of ITNs in combating malaria has been declining. Underlying heterogeneities in the nature of malaria, combined with environmental factors such as temperature lead to complex malaria transmission and control dynamics. In particular, temperature plays a significant role in determining the risk of malaria since it influences the growth and survival of mosquitoes and the malaria parasite. Here, a unifying mechanistic framework that integrates malaria dynamics with waning ITN-efficacy and temperature change is developed and used to assess the impact of interactions between significant sources of variation (e.g., temperature) and waning ITN-efficacy on the risk of malaria transmission and the success of ITN programs. The model exhibits a backward bifurcation when ITN-efficacy is constant implying that control efforts must be stepped up and sustained a bit longer even when the reproduction number is slightly less than one. The study shows that malaria is more effectively controlled with ITNs that have a longer lifespan and if ITNs are replaced before the end of their expiration period. Also, failing to account for waning ITN-efficacy leads to an underestimation of disease risk, burden, and effort level required to contain the disease. Local and global sensitivity analyses show that control and temperature-related parameters are primary drivers of the reproduction number and the human disease burden, highlighting the significance of temperature on malaria dynamics. Furthermore, the study shows that the human disease burden is optimal at a temperature of ≈28°C and that high seasonal variations can trigger major malaria outbreaks even in regions with low mean temperatures. Additionally, accounting for both seasonality and decay in ITN-efficacy leads to complex malaria patterns. To sum it up, insights into the sensitivity of malaria dynamics on temperature are useful in assessing the potential impact of changes in temperature on malaria risk. Also, a malaria control program, which ensures that ITNs are replaced regularly and early enough, and that educates at risk populations on proper use and care for ITNs is necessary for reducing the burden of malaria.
Collapse
Affiliation(s)
- Calistus N Ngonghala
- Department of Mathematics, University of Florida, Gainesville, FL 32611, USA; Emerging Pathogens Institute, University of Florida, Gainesville, FL 32610, USA; Center for African Studies, University of Florida, Gainesville, FL 32611, USA.
| |
Collapse
|
4
|
Agyekum TP, Arko-Mensah J, Botwe PK, Hogarh JN, Issah I, Dwomoh D, Billah MK, Dadzie SK, Robins TG, Fobil JN. Effects of Elevated Temperatures on the Growth and Development of Adult Anopheles gambiae (s.l.) (Diptera: Culicidae) Mosquitoes. JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:1413-1420. [PMID: 35452118 PMCID: PMC9278826 DOI: 10.1093/jme/tjac046] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Indexed: 06/01/2023]
Abstract
Higher temperatures expected in a future warmer climate could adversely affect the growth and development of mosquitoes. This study investigated the effects of elevated temperatures on longevity, gonotrophic cycle length, biting rate, fecundity, and body size of Anopheles gambiae (s.l.) (Diptera: Culicidae) mosquitoes. Anopheles gambiae (s.l.) eggs obtained from laboratory established colonies were reared under eight temperature regimes (25, 28, 30, 32, 34, 36, 38, and 40°C), and 80 ± 10% RH. All adults were allowed to feed on a 10% sugar solution soaked in cotton wool; however, some mosquitoes were provided blood meal using guinea pig. Longevity was estimated for both blood-fed and non-blood-fed mosquitoes and analyzed using the Kaplan-Meier survival analysis. One-way ANOVA was used to test the effect of temperature on gonotrophic cycle length, biting rate, and fecundity. Adult measurement data were log-transformed and analyzed using ordinary least square regression with robust standard errors. Increasing temperature significantly decreased the longevity of both blood-fed (Log-rank test; X2(4) = 904.15, P < 0.001) and non-blood-fed (Log-rank test; X2(4) = 1163.60, P < 0.001) mosquitoes. In addition, the fecundity of mosquitoes decreased significantly (ANOVA; F(2,57) = 3.46, P = 0.038) with an increase in temperature. Body size (β = 0.14, 95% CI, 0.16, 0.12, P < 0.001) and proboscis length (β = 0.13, 95% CI, 0.17, 0.09, P < 0.001) significantly decreased with increasing temperature from 25 to 34°C. Increased temperatures expected in a future warmer climate could cause some unexpected effects on mosquitoes by directly influencing population dynamics and malaria transmission.
Collapse
Affiliation(s)
| | - John Arko-Mensah
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Paul K Botwe
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Jonathan N Hogarh
- Department of Environmental Science, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Ibrahim Issah
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Duah Dwomoh
- Department of Biostatistics, School of Public Health, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Maxwell K Billah
- Department of Animal Biology and Conservation Science, University of Ghana, Accra, Ghana
| | - Samuel K Dadzie
- Parasitology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Thomas G Robins
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Julius N Fobil
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Accra, Ghana
| |
Collapse
|
5
|
Marti-Soler H, Máquina M, Opiyo M, Alafo C, Sherrard-Smith E, Malheia A, Cuamba N, Sacoor C, Rabinovich R, Aide P, Saúte F, Paaijmans K. Effect of wall type, delayed mortality and mosquito age on the residual efficacy of a clothianidin-based indoor residual spray formulation (SumiShield™ 50WG) in southern Mozambique. PLoS One 2021; 16:e0248604. [PMID: 34351936 PMCID: PMC8341595 DOI: 10.1371/journal.pone.0248604] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 07/06/2021] [Indexed: 11/22/2022] Open
Abstract
Indoor residual spraying (IRS) is one of the main malaria vector control strategies in Mozambique alongside the distribution of insecticide treated nets. As part of the national insecticide resistance management strategy, Mozambique introduced SumiShield™ 50WG, a third generation IRS product, in 2018. Its residual efficacy was assessed in southern Mozambique during the 2018-2019 malaria season. Using a susceptible Anopheles arabiensis strain, residual efficacy was assessed on two different wall surfaces, cement and mud-plastered walls, using standard WHO (World Health Organization) cone bioassay tests at three different heights. Female mosquitoes of two age groups (2-5 and 13-26 day old) were exposed for 30 minutes, after which mortality was observed 24h, 48h, 72h, and 96h and 120h post-exposure to assess (delayed) mortality. Lethal times (LT) 90, LT50 and LT10 were estimated using Bayesian models. Mortality 24h post exposure was consistently below 80%, the current WHO threshold value for effective IRS, in both young and old mosquitoes, regardless of wall surface type. Considering delayed mortality, residual efficacies (mosquito mortality equal or greater than 80%) ranged from 1.5 to ≥12.5 months, with the duration depending on mortality time post exposure, wall type and mosquito age. Looking at mortality 72h after exposure, residual efficacy was between 6.5 and 9.5 months, depending on wall type and mosquito age. The LT50 and LT10 (i.e. 90% of the mosquitoes survive exposure to the insecticides) values were consistently higher for older mosquitoes (except for LT10 values for 48h and 72h post-exposure mortality) and ranged from 0.9 to 5.8 months and 0.2 to 7.8 months for LT50 and LT10, respectively. The present study highlights the need for assessing mosquito mortality beyond the currently recommended 24h post exposure. Failure to do so may lead to underestimation of the residual efficacy of IRS products, as delayed mortality will lead to a further reduction in mosquito vector populations and potentially negatively impact disease transmission. Monitoring residual efficacy on relevant wall surfaces, including old mosquitoes that are ultimately responsible for malaria transmission, and assessing delayed mortalities are critical to provide accurate and actionable data to guide vector control programmes.
Collapse
Affiliation(s)
| | - Mara Máquina
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Mercy Opiyo
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Celso Alafo
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
- Goodbye Malaria, Tchau Tchau Malaria Foundation, Mozambique
| | - Ellie Sherrard-Smith
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, United Kingdom
| | - Arlindo Malheia
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Nelson Cuamba
- Programa Nacional de Controlo da Malária, Ministério da Saúde, Maputo, Mozambique
- PMI VectorLink Project, Abt Associates Inc., Maputo, Mozambique
| | - Charfudin Sacoor
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Regina Rabinovich
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain
- Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Pedro Aide
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
- Instituto Nacional da Saúde, Ministério da Saúde, Maputo, Mozambique
| | - Francisco Saúte
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Krijn Paaijmans
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
- Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- The Biodesign Center for Immunotherapy, Vaccines, and Virotherapy, Arizona State University, Tempe, Arizona, United States of America
| |
Collapse
|
6
|
Agyekum TP, Botwe PK, Arko-Mensah J, Issah I, Acquah AA, Hogarh JN, Dwomoh D, Robins TG, Fobil JN. A Systematic Review of the Effects of Temperature on Anopheles Mosquito Development and Survival: Implications for Malaria Control in a Future Warmer Climate. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:7255. [PMID: 34299706 PMCID: PMC8306597 DOI: 10.3390/ijerph18147255] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 06/17/2021] [Accepted: 06/22/2021] [Indexed: 12/17/2022]
Abstract
The rearing temperature of the immature stages can have a significant impact on the life-history traits and the ability of adult mosquitoes to transmit diseases. This review assessed published evidence of the effects of temperature on the immature stages, life-history traits, insecticide susceptibility, and expression of enzymes in the adult Anopheles mosquito. Original articles published through 31 March 2021 were systematically retrieved from Scopus, Google Scholar, Science Direct, PubMed, ProQuest, and Web of Science databases. After applying eligibility criteria, 29 studies were included. The review revealed that immature stages of An. arabiensis were more tolerant (in terms of survival) to a higher temperature than An. funestus and An. quadriannulatus. Higher temperatures resulted in smaller larval sizes and decreased hatching and pupation time. The development rate and survival of An. stephensi was significantly reduced at a higher temperature than a lower temperature. Increasing temperatures decreased the longevity, body size, length of the gonotrophic cycle, and fecundity of Anopheles mosquitoes. Higher rearing temperatures increased pyrethroid resistance in adults of the An. arabiensis SENN DDT strain, and increased pyrethroid tolerance in the An. arabiensis SENN strain. Increasing temperature also significantly increased Nitric Oxide Synthase (NOS) expression and decreased insecticide toxicity. Both extreme low and high temperatures affect Anopheles mosquito development and survival. Climate change could have diverse effects on Anopheles mosquitoes. The sensitivities of Anopeheles mosquitoes to temperature differ from species to species, even among the same complex. Notwithstanding, there seem to be limited studies on the effects of temperature on adult life-history traits of Anopheles mosquitoes, and more studies are needed to clarify this relationship.
Collapse
Affiliation(s)
- Thomas P. Agyekum
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra 00233, Ghana; (P.K.B.); (J.A.-M.); (I.I.); (A.A.A.); (J.N.F.)
| | - Paul K. Botwe
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra 00233, Ghana; (P.K.B.); (J.A.-M.); (I.I.); (A.A.A.); (J.N.F.)
| | - John Arko-Mensah
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra 00233, Ghana; (P.K.B.); (J.A.-M.); (I.I.); (A.A.A.); (J.N.F.)
| | - Ibrahim Issah
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra 00233, Ghana; (P.K.B.); (J.A.-M.); (I.I.); (A.A.A.); (J.N.F.)
| | - Augustine A. Acquah
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra 00233, Ghana; (P.K.B.); (J.A.-M.); (I.I.); (A.A.A.); (J.N.F.)
| | - Jonathan N. Hogarh
- Department of Environmental Science, Kwame Nkrumah University of Science and Technology, Kumasi 00233, Ghana;
| | - Duah Dwomoh
- Department of Biostatistics, School of Public Health, College of Health Sciences, University of Ghana, Accra 00233, Ghana;
| | - Thomas G. Robins
- Department of Environmental Health Sciences, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109, USA;
| | - Julius N. Fobil
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra 00233, Ghana; (P.K.B.); (J.A.-M.); (I.I.); (A.A.A.); (J.N.F.)
| |
Collapse
|
7
|
Thongsripong P, Hyman JM, Kapan DD, Bennett SN. Human-Mosquito Contact: A Missing Link in Our Understanding of Mosquito-Borne Disease Transmission Dynamics. ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA 2021; 114:397-414. [PMID: 34249219 PMCID: PMC8266639 DOI: 10.1093/aesa/saab011] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Indexed: 05/26/2023]
Abstract
Despite the critical role that contact between hosts and vectors, through vector bites, plays in driving vector-borne disease (VBD) transmission, transmission risk is primarily studied through the lens of vector density and overlooks host-vector contact dynamics. This review article synthesizes current knowledge of host-vector contact with an emphasis on mosquito bites. It provides a framework including biological and mathematical definitions of host-mosquito contact rate, blood-feeding rate, and per capita biting rates. We describe how contact rates vary and how this variation is influenced by mosquito and vertebrate factors. Our framework challenges a classic assumption that mosquitoes bite at a fixed rate determined by the duration of their gonotrophic cycle. We explore alternative ecological assumptions based on the functional response, blood index, forage ratio, and ideal free distribution within a mechanistic host-vector contact model. We highlight that host-vector contact is a critical parameter that integrates many factors driving disease transmission. A renewed focus on contact dynamics between hosts and vectors will contribute new insights into the mechanisms behind VBD spread and emergence that are sorely lacking. Given the framework for including contact rates as an explicit component of mathematical models of VBD, as well as different methods to study contact rates empirically to move the field forward, researchers should explicitly test contact rate models with empirical studies. Such integrative studies promise to enhance understanding of extrinsic and intrinsic factors affecting host-vector contact rates and thus are critical to understand both the mechanisms driving VBD emergence and guiding their prevention and control.
Collapse
Affiliation(s)
- Panpim Thongsripong
- Department of Microbiology, California Academy of Sciences, 55 Music Concourse Drive, San Francisco, CA 94118, USA
| | - James M Hyman
- Department of Mathematics, Tulane University, 6823 St. Charles Avenue, New Orleans, LA 70118, USA
| | - Durrell D Kapan
- Department of Entomology and Center for Comparative Genomics, Institute of Biodiversity Sciences and Sustainability, California Academy of Sciences, 55 Music Concourse Drive, San Francisco, CA 94118, USA
- Center for Conservation and Research Training, Pacific Biosciences Research Center, University of Hawai’i at Manoa, 3050 Maile Way, Honolulu, HI 96822
| | - Shannon N Bennett
- Department of Microbiology, California Academy of Sciences, 55 Music Concourse Drive, San Francisco, CA 94118, USA
| |
Collapse
|
8
|
Athni TS, Shocket MS, Couper LI, Nova N, Caldwell IR, Caldwell JM, Childress JN, Childs ML, De Leo GA, Kirk DG, MacDonald AJ, Olivarius K, Pickel DG, Roberts SO, Winokur OC, Young HS, Cheng J, Grant EA, Kurzner PM, Kyaw S, Lin BJ, López RC, Massihpour DS, Olsen EC, Roache M, Ruiz A, Schultz EA, Shafat M, Spencer RL, Bharti N, Mordecai EA. The influence of vector-borne disease on human history: socio-ecological mechanisms. Ecol Lett 2021; 24:829-846. [PMID: 33501751 PMCID: PMC7969392 DOI: 10.1111/ele.13675] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/08/2020] [Accepted: 12/09/2020] [Indexed: 01/14/2023]
Abstract
Vector-borne diseases (VBDs) are embedded within complex socio-ecological systems. While research has traditionally focused on the direct effects of VBDs on human morbidity and mortality, it is increasingly clear that their impacts are much more pervasive. VBDs are dynamically linked to feedbacks between environmental conditions, vector ecology, disease burden, and societal responses that drive transmission. As a result, VBDs have had profound influence on human history. Mechanisms include: (1) killing or debilitating large numbers of people, with demographic and population-level impacts; (2) differentially affecting populations based on prior history of disease exposure, immunity, and resistance; (3) being weaponised to promote or justify hierarchies of power, colonialism, racism, classism and sexism; (4) catalysing changes in ideas, institutions, infrastructure, technologies and social practices in efforts to control disease outbreaks; and (5) changing human relationships with the land and environment. We use historical and archaeological evidence interpreted through an ecological lens to illustrate how VBDs have shaped society and culture, focusing on case studies from four pertinent VBDs: plague, malaria, yellow fever and trypanosomiasis. By comparing across diseases, time periods and geographies, we highlight the enormous scope and variety of mechanisms by which VBDs have influenced human history.
Collapse
Affiliation(s)
- Tejas S. Athni
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Marta S. Shocket
- Department of Biology, Stanford University, Stanford, CA, USA
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
| | - Lisa I. Couper
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Nicole Nova
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Iain R. Caldwell
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, Australia
| | - Jamie M. Caldwell
- Department of Biology, Stanford University, Stanford, CA, USA
- Department of Biology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Jasmine N. Childress
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Marissa L. Childs
- Emmett Interdisciplinary Program in Environment and Resources, Stanford University, Stanford, CA, USA
| | - Giulio A. De Leo
- Hopkins Marine Station of Stanford University, Pacific Grove, CA, USA
- Woods Institute for the Environment, Stanford University, Stanford, CA, USA
| | - Devin G. Kirk
- Department of Biology, Stanford University, Stanford, CA, USA
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Andrew J. MacDonald
- Bren School of Environmental Science and Management, University of California, Santa Barbara, CA, USA
- Earth Research Institute, University of California, Santa Barbara, CA, USA
| | | | - David G. Pickel
- Department of Classics, Stanford University, Stanford, CA, USA
| | | | - Olivia C. Winokur
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Hillary S. Young
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Julian Cheng
- Department of Biology, Stanford University, Stanford, CA, USA
| | | | | | - Saw Kyaw
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Bradford J. Lin
- Department of Biology, Stanford University, Stanford, CA, USA
| | | | | | - Erica C. Olsen
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Maggie Roache
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Angie Ruiz
- Department of Biology, Stanford University, Stanford, CA, USA
| | | | - Muskan Shafat
- Department of Biology, Stanford University, Stanford, CA, USA
| | | | - Nita Bharti
- Department of Biology, Center for Infectious Disease Dynamics, Penn State University, University Park, PA, USA
| | | |
Collapse
|
9
|
Cheng YC, Lee FJ, Hsu YT, Slud EV, Hsiung CA, Chen CH, Liao CL, Wen TH, Chang CW, Chang JH, Wu HY, Chang TP, Lin PS, Ho HP, Hung WF, Chou JD, Tsou HH. Real-time dengue forecast for outbreak alerts in Southern Taiwan. PLoS Negl Trop Dis 2020; 14:e0008434. [PMID: 32716983 PMCID: PMC7384612 DOI: 10.1371/journal.pntd.0008434] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 05/29/2020] [Indexed: 11/18/2022] Open
Abstract
Dengue fever is a viral disease transmitted by mosquitoes. In recent decades, dengue fever has spread throughout the world. In 2014 and 2015, southern Taiwan experienced its most serious dengue outbreak in recent years. Some statistical models have been established in the past, however, these models may not be suitable for predicting huge outbreaks in 2014 and 2015. The control of dengue fever has become the primary task of local health agencies. This study attempts to predict the occurrence of dengue fever in order to achieve the purpose of timely warning. We applied a newly developed autoregressive model (AR model) to assess the association between daily weather variability and daily dengue case number in 2014 and 2015 in Kaohsiung, the largest city in southern Taiwan. This model also contained additional lagged weather predictors, and developed 5-day-ahead and 15-day-ahead predictive models. Our results indicate that numbers of dengue cases in Kaohsiung are associated with humidity and the biting rate (BR). Our model is simple, intuitive and easy to use. The developed model can be embedded in a "real-time" schedule, and the data (at present) can be updated daily or weekly based on the needs of public health workers. In this study, a simple model using only meteorological factors performed well. The proposed real-time forecast model can help health agencies take public health actions to mitigate the influences of the epidemic. Meteorological conditions are the most frequently mentioned factors in the study of dengue fever. Some of the main factors other than the purely meteorological about which the public-health authorities might have data, such as numbers of cases or other current measurements of dengue outbreaks in neighboring cities, had been used in some of the past dengue studies. In this study, we developed models for predicting dengue case number based on past dengue case data and meteorological data. The goal of the models is to provide early warning of the occurrence of dengue fever to assist public health agencies in preparing an epidemic response plan.
Collapse
Affiliation(s)
- Yu-Chieh Cheng
- Division of Biostatistics and Bioinformatics, Institute of Population Health Sciences, National Health Research Institutes, Miaoli County, Taiwan
| | - Fang-Jing Lee
- National Mosquito-Borne Diseases Control Research Center, National Health Research Institutes, Miaoli County, Taiwan
| | - Ya-Ting Hsu
- Division of Biostatistics and Bioinformatics, Institute of Population Health Sciences, National Health Research Institutes, Miaoli County, Taiwan
| | - Eric V. Slud
- Department of Mathematics, University of Maryland, College Park, Maryland, United States of America
| | - Chao A. Hsiung
- Division of Biostatistics and Bioinformatics, Institute of Population Health Sciences, National Health Research Institutes, Miaoli County, Taiwan
| | - Chun-Hong Chen
- National Mosquito-Borne Diseases Control Research Center, National Health Research Institutes, Miaoli County, Taiwan
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli County, Taiwan
| | - Ching-Len Liao
- National Mosquito-Borne Diseases Control Research Center, National Health Research Institutes, Miaoli County, Taiwan
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli County, Taiwan
| | - Tzai-Hung Wen
- Department of Geography, National Taiwan University, Taipei, Taiwan
| | - Chiu-Wen Chang
- Department of Health, Kaohsiung City Government, Kaohsiung City, Taiwan
| | - Jui-Hun Chang
- Environmental Protection Bureau, Kaohsiung City Government, Kaohsiung City, Taiwan
| | - Hsiao-Yu Wu
- Division of Biostatistics and Bioinformatics, Institute of Population Health Sciences, National Health Research Institutes, Miaoli County, Taiwan
| | - Te-Pin Chang
- National Mosquito-Borne Diseases Control Research Center, National Health Research Institutes, Miaoli County, Taiwan
| | - Pei-Sheng Lin
- Division of Biostatistics and Bioinformatics, Institute of Population Health Sciences, National Health Research Institutes, Miaoli County, Taiwan
| | - Hui-Pin Ho
- Department of Health, Kaohsiung City Government, Kaohsiung City, Taiwan
| | - Wen-Feng Hung
- Soil and groundwater pollution remediation center, CPC Corporation, Taiwan
| | - Jing-Dong Chou
- Environmental Protection Bureau, Kaohsiung City Government, Kaohsiung City, Taiwan
| | - Hsiao-Hui Tsou
- Division of Biostatistics and Bioinformatics, Institute of Population Health Sciences, National Health Research Institutes, Miaoli County, Taiwan
- Graduate Institute of Biostatistics, College of Public Health, China Medical University, Taichung, Taiwan
- * E-mail:
| |
Collapse
|
10
|
Siya A, Kalule BJ, Ssentongo B, Lukwa AT, Egeru A. Malaria patterns across altitudinal zones of Mount Elgon following intensified control and prevention programs in Uganda. BMC Infect Dis 2020; 20:425. [PMID: 32552870 PMCID: PMC7301530 DOI: 10.1186/s12879-020-05158-5] [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: 02/12/2020] [Accepted: 06/12/2020] [Indexed: 12/22/2022] Open
Abstract
Background Malaria remains a major tropical vector-borne disease of immense public health concern owing to its debilitating effects in sub-Saharan Africa. Over the past 30 years, the high altitude areas in Eastern Africa have been reported to experience increased cases of malaria. Governments including that of the Republic of Uganda have responded through intensifying programs that can potentially minimize malaria transmission while reducing associated fatalities. However, malaria patterns following these intensified control and prevention interventions in the changing climate remains widely unexplored in East African highland regions. This study thus analyzed malaria patterns across altitudinal zones of Mount Elgon, Uganda. Methods Times-series data on malaria cases (2011–2017) from five level III local health centers occurring across three altitudinal zones; low, mid and high altitude was utilized. Inverse Distance Weighted (IDW) interpolation regression and Mann Kendall trend test were used to analyze malaria patterns. Vegetation attributes from the three altitudinal zones were analyzed using Normalized Difference Vegetation Index (NDVI) was used to determine the Autoregressive Integrated Moving Average (ARIMA) model was used to project malaria patterns for a 7 year period. Results Malaria across the three zones declined over the study period. The hotspots for malaria were highly variable over time in all the three zones. Rainfall played a significant role in influencing malaria burdens across the three zones. Vegetation had a significant influence on malaria in the higher altitudes. Meanwhile, in the lower altitude, human population had a significant positive correlation with malaria cases. Conclusions Despite observed decline in malaria cases across the three altitudinal zones, the high altitude zone became a malaria hotspot as cases variably occurred in the zone. Rainfall played the biggest role in malaria trends. Human population appeared to influence malaria incidences in the low altitude areas partly due to population concentration in this zone. Malaria control interventions ought to be strengthened and strategically designed to achieve no malaria cases across all the altitudinal zones. Integration of climate information within malaria interventions can also strengthen eradication strategies of malaria in such differentiated altitudinal zones.
Collapse
Affiliation(s)
- Aggrey Siya
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P.O. Box 7062, Kampala, Uganda. .,Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa.
| | - Bosco John Kalule
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P.O. Box 7062, Kampala, Uganda
| | - Benard Ssentongo
- College of Agricultural and Environmental Sciences, Makerere University, P.O. Box 7062, Kampala, Uganda
| | - Akim Tafadzwa Lukwa
- Faculty of Health Sciences, School of Public Health and Family Medicine, Health Economics Unit, University of Cape Town, Cape Town, South Africa
| | - Anthony Egeru
- College of Agricultural and Environmental Sciences, Makerere University, P.O. Box 7062, Kampala, Uganda
| |
Collapse
|
11
|
Mayton EH, Tramonte AR, Wearing HJ, Christofferson RC. Age-structured vectorial capacity reveals timing, not magnitude of within-mosquito dynamics is critical for arbovirus fitness assessment. Parasit Vectors 2020; 13:310. [PMID: 32539759 PMCID: PMC7296759 DOI: 10.1186/s13071-020-04181-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 06/10/2020] [Indexed: 12/20/2022] Open
Abstract
Background Transmission dynamics of arboviruses like Zika virus are often evaluated by vector competence (the proportion of infectious vectors given exposure) and the extrinsic incubation period (EIP, the time it takes for a vector to become infectious), but vector age is another critical driver of transmission dynamics. Vectorial capacity (VC) is a measure of transmission potential of a vector-pathogen system, but how these three components, EIP, vector competence and vector age, affect VC in concert still needs study. Methods The interaction of vector competence, EIP, and mosquito age at the time of infection acquisition (Ageacquisition) was experimentally measured in an Aedes aegypti-ZIKV model system, as well as the age-dependence of probability of survival and the willingness to bite. An age-structured vectorial capacity framework (VCage) was then developed using both EIPMin and EIPMax, defined as the time to first observed minimum proportion of transmitting mosquitoes and the time to observed maximum proportion of transmitting mosquitoes. Results The within-mosquito dynamics of vector competence/EIP were not significant among treatments where mosquitoes were exposed at different ages. However, VCage revealed: (i) age-dependence in vector-virus interactions is important for transmission success; (ii) lower vector competence but at shorter EIPs was sufficient for transmission perpetuation; and (iii) R0 may be overestimated by using non-age-structured VC. Conclusions The results indicate that ultimately the temporal component of the virus-vector dynamics is most critical, especially when exposure occurred at advanced mosquito age. While our study is limited to a single virus-vector system, and a multitude of other factors affect both vector competence and mosquito mortality, our methods can be extrapolated to these other scenarios. Results indicate that how ‘highly’ or ‘negligibly’ competent vectors are categorized may need adjustment.![]()
Collapse
Affiliation(s)
- E Handly Mayton
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
| | - A Ryan Tramonte
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
| | - Helen J Wearing
- Departments of Biology and Mathematics & Statistics, University of New Mexico, Albuquerque, NM, USA
| | - Rebecca C Christofferson
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA. .,Center for Computation and Technology, Louisiana State University, Baton Rouge, LA, USA.
| |
Collapse
|
12
|
Cáceres Carrera L, Victoria C, Ramirez JL, Jackman C, Calzada JE, Torres R. Study of the epidemiological behavior of malaria in the Darien Region, Panama. 2015-2017. PLoS One 2019; 14:e0224508. [PMID: 31730618 PMCID: PMC6857920 DOI: 10.1371/journal.pone.0224508] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 10/15/2019] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Malaria is endemic in Darién and an assessment of the different factors affecting its epidemiology is crucial for the development of adequate strategies of surveillance, prevention, and disease control. The objective of this study was to determine the main characteristics of the epidemiological behavior of malaria in the Darien region. METHODS This research was comprised of a retrospective analysis to determine the incidence and malaria distribution in the Darien region from 2015 to 2017. We evaluated malaria indicators, disease distribution, incidence (by age group and sex), diagnostic methods, treatment, and control measures. In addition, we examined the cross-border migration activity and its possible contribution to the maintenance and distribution of malaria. RESULTS During the period of 2015-2017, we examined 41,141 thick blood smear samples, out of which 501 tested positive for malaria. Plasmodium vivax was responsible for 92.2% of those infections. Males comprised 62.7% of the total diagnosed cases. Meanwhile, a similar percentage, 62.7%, of the total cases were registered in economically active ages. The more frequent symptoms included fever (99.4%) and chills (97.4%), with 53.1% of cases registering between 2,000 and 6,000 parasites/μl of blood. The annual parasitic incidence (API) average was 3.0/1,000 inhabitants, while the slide positivity rate (SPR) was 1.2% and the annual blood examination rate (ABER) 22.5%. In Darién there is a constant internal and cross-border migration movement between Panama and Colombia. Malaria control measures consisted of the active and passive search of suspected cases and of the application of vector control measures. CONCLUSION This study provides an additional perspective on malaria epidemiology in Darién. Additional efforts are required to intensify malaria surveillance and to achieve an effective control, eventually moving closer to the objective of malaria elimination. At the same time, there is a need for more eco-epidemiological, entomological and migratory studies to determine how these factors contribute to the patterns of maintenance and dissemination of malaria.
Collapse
Affiliation(s)
- Lorenzo Cáceres Carrera
- Department of Medical Entomology, Gorgas Memorial Institute of Health Studies, Panama City, Panama
- * E-mail:
| | | | - Jose L. Ramirez
- Crop Bioprotection Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, United States Department of Agriculture, Peoria, Illinois, United States of America
| | - Carmela Jackman
- Epidemiology Department of the Darién Region, Ministry of Health, Panama City, Panama
| | - José E. Calzada
- Direcction of Research and Technological Development, Gorgas Memorial Institute of Health Studies, Panama City, Panama
| | - Rolando Torres
- Department of Medical Entomology, Gorgas Memorial Institute of Health Studies, Panama City, Panama
| |
Collapse
|
13
|
Catano-Lopez A, Rojas-Diaz D, Laniado H, Arboleda-Sánchez S, Puerta-Yepes ME, Lizarralde-Bejarano DP. An alternative model to explain the vectorial capacity using as example Aedes aegypti case in dengue transmission. Heliyon 2019; 5:e02577. [PMID: 31687486 PMCID: PMC6820089 DOI: 10.1016/j.heliyon.2019.e02577] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 05/01/2019] [Accepted: 10/01/2019] [Indexed: 11/30/2022] Open
Abstract
Vectorial capacity (VC), as a concept that describes the potential of a vector to transmit a pathogen, has had historical problems related to lacks in dimensional significance and high error propagation from parameters that take part in the model to output. Hence, values estimated with those equations are not sufficiently reliable to consider in control strategies or vector population study. In this paper, we propose a new VC model consistent at dimensional level, i.e., the definition and the equation of VC have same and consistent units, with a parameter estimation method and mathematical structure that reduces the uncertainty in model output, using as a case of study an Aedes aegypti population of the municipality of Bello, Colombia. After a literature review, we selected one VC equation following biological, measurability and dimensional criteria, then we rendered a local and global sensitivity analysis, identifying the mortality rate of mosquitoes as a target component of the equation. Thus, we studied the Weibull and Exponential distributions as probabilistic models that represent the expectation of mosquitoes infective life, intending to include the best distribution in a selected VC structure. The proposed mortality rate estimation method includes a new parameter that represents an increase or decrease in vector mortality, as it may apply. We noticed that its estimation reduces the uncertainty associated with the expectation of mosquitoes' infective life expression, which also reduces the output range and variance in almost a half.
Collapse
Affiliation(s)
- Alexandra Catano-Lopez
- Departamento de Ciencias Matemáticas, Escuela de Ciencias, Universidad EAFIT, Carrera 49 No. 7 Sur-50, Medellín 050022, Colombia
| | - Daniel Rojas-Diaz
- Departamento de Ciencias Biológicas, Escuela de Ciencias, Universidad EAFIT, Carrera 49 No. 7 Sur-50, Medellín 050022, Colombia
| | - Henry Laniado
- Departamento de Ciencias Matemáticas, Escuela de Ciencias, Universidad EAFIT, Carrera 49 No. 7 Sur-50, Medellín 050022, Colombia
| | - Sair Arboleda-Sánchez
- Grupo de Biología y Control de Enfermedades Infecciosas-BCEI, Universidad de Antioquia, Calle 70 No. 52-21, Medellín 050010, Colombia
| | - María Eugenia Puerta-Yepes
- Departamento de Ciencias Matemáticas, Escuela de Ciencias, Universidad EAFIT, Carrera 49 No. 7 Sur-50, Medellín 050022, Colombia
| | - Diana Paola Lizarralde-Bejarano
- Departamento de Ciencias Matemáticas, Escuela de Ciencias, Universidad EAFIT, Carrera 49 No. 7 Sur-50, Medellín 050022, Colombia
| |
Collapse
|
14
|
Barreaux AMG, Oumbouke WA, Tia IZ, Brou N, Koffi AA, N'guessan R, Thomas MB. Semi-field evaluation of the cumulative effects of a "Lethal House Lure" on malaria mosquito mortality. Malar J 2019; 18:298. [PMID: 31470873 PMCID: PMC6716835 DOI: 10.1186/s12936-019-2936-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Accepted: 08/24/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND There is growing interest in the potential to modify houses to target mosquitoes with insecticides or repellents as they search for human hosts. One version of this 'Lethal House Lure' approach is the In2Care® EaveTube, which consists of a section of polyvinyl chloride (PVC) pipe fitted into a closed eave, with an insert comprising electrostatic netting treated with insecticide powder placed inside the tube. Preliminary evidence suggests that when combined with screening of doors and windows, there is a reduction in entry of mosquitoes and an increase in mortality. However, the rate of overnight mortality remains unclear. The current study used a field enclosure built around experimental huts to investigate the mortality of cohorts of mosquitoes over multiple nights. METHODS Anopheles gambiae sensu lato mosquitoes were collected from the field as larvae and reared through to adult. Three-to-five days old adult females were released inside an enclosure housing two modified West African style experimental huts at a field site in M'be, Côte d'Ivoire. Huts were either equipped with insecticide-treated tubes at eave height and had closed windows (treatment) or had open windows and open tubes (controls). The number of host-seeking mosquitoes entering the huts and cumulative mortality were monitored over 2 or 4 days. RESULTS Very few (0-0.4%) mosquitoes were able to enter huts fitted with insecticide-treated tubes and closed windows. In contrast, mosquitoes continually entered the control huts, with a cumulative mean of 50-80% over 2 to 4 days. Baseline mortality with control huts was approximately 2-4% per day, but the addition of insecticide-treated tubes increased mortality to around 25% per day. Overall cumulative mortality was estimated to be up to 87% over 4 days when huts were fitted with tubes. CONCLUSION Only 20-25% of mosquitoes contacted insecticide-treated tubes or entered control huts in a given night. However, mosquitoes continue to host search over sequential nights, and this can lead to high cumulative mortality over 2 to 4 days. This mortality should contribute to community-level reduction in transmission assuming sufficient coverage of the intervention.
Collapse
Affiliation(s)
- Antoine M G Barreaux
- Department of Entomology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA, 16802, USA.
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK.
| | - Welbeck A Oumbouke
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Innocent Zran Tia
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
| | - N'guessan Brou
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
| | - Alphonsine A Koffi
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
| | - Raphaël N'guessan
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Matthew B Thomas
- Department of Entomology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA, 16802, USA
| |
Collapse
|
15
|
Waite JL, Suh E, Lynch PA, Thomas MB. Exploring the lower thermal limits for development of the human malaria parasite, Plasmodium falciparum. Biol Lett 2019; 15:20190275. [PMID: 31238857 PMCID: PMC6597502 DOI: 10.1098/rsbl.2019.0275] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The rate of malaria transmission is strongly determined by parasite development time in the mosquito, known as the extrinsic incubation period (EIP), since the quicker parasites develop, the greater the chance that the vector will survive long enough for the parasite to complete development and be transmitted. EIP is known to be temperature-dependent but this relationship is surprisingly poorly characterized. There is a single degree-day model for EIP of Plasmodium falciparum that derives from a limited number of poorly controlled studies conducted almost a century ago. Here, we show that the established degree-day model greatly underestimates the rate of development of P. falciparum in both Anopheles stephensi and An. gambiae mosquitoes at temperatures in the range of 17–20°C. We also show that realistic daily temperature fluctuation further speeds parasite development. These novel results challenge one of the longest standing models in malaria biology and have potentially important implications for understanding the impacts of future climate change.
Collapse
Affiliation(s)
- Jessica L Waite
- 1 Center for Infectious Disease Dynamics and Department of Entomology, The Pennsylvania State University , University Park, PA 16802 , USA
| | - Eunho Suh
- 1 Center for Infectious Disease Dynamics and Department of Entomology, The Pennsylvania State University , University Park, PA 16802 , USA
| | - Penelope A Lynch
- 2 College of Life and Environmental Sciences, University of Exeter , Penryn Campus, Cornwall TR10 9FE , UK
| | - Matthew B Thomas
- 1 Center for Infectious Disease Dynamics and Department of Entomology, The Pennsylvania State University , University Park, PA 16802 , USA
| |
Collapse
|
16
|
Wang X, Zou X. Modeling the Potential Role of Engineered Symbiotic Bacteria in Malaria Control. Bull Math Biol 2019; 81:2569-2595. [PMID: 31161557 DOI: 10.1007/s11538-019-00619-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 05/25/2019] [Indexed: 11/29/2022]
Abstract
Recent experimental study suggests that the engineered symbiotic bacteria Serratia AS1 may provide a novel, effective and sustainable biocontrol of malaria. These recombinant bacteria have been shown to be able to rapidly disseminate throughout mosquito populations and to efficiently inhibit development of malaria parasites in mosquitoes in controlled laboratory experiments. In this paper, we develop a climate-based malaria model which involves both vertical and horizontal transmissions of the engineered Serratia AS1 bacteria in mosquito population. We show that the dynamics of the model system is totally determined by the vector reproduction ratio [Formula: see text], and the basic reproduction ratio [Formula: see text]. If [Formula: see text], then the mosquito-free state is globally attractive. If [Formula: see text] and [Formula: see text], then the disease-free periodic solution is globally attractive. If [Formula: see text] and [Formula: see text], then the positive periodic solution is globally attractive. Numerically, we verify the obtained analytic result and evaluate the effects of releasing the engineered Serratia AS1 bacteria in field by conducting a case study for Douala, Cameroon. We find that ideally, by using Serratia AS1 alone, it takes at least 25 years to eliminate malaria from Douala. This implies that continued long-term investment is needed in the fight against malaria and confirms the necessity of integrating multiple control measures.
Collapse
Affiliation(s)
- Xiunan Wang
- Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, AB, T6G 2G1, Canada.
| | - Xingfu Zou
- Department of Applied Mathematics, University of Western Ontario, London, ON, N6A 5B7, Canada
| |
Collapse
|
17
|
Ng V, Rees EE, Lindsay LR, Drebot MA, Brownstone T, Sadeghieh T, Khan SU. Could exotic mosquito-borne diseases emerge in Canada with climate change? CANADA COMMUNICABLE DISEASE REPORT = RELEVE DES MALADIES TRANSMISSIBLES AU CANADA 2019; 45:98-107. [PMID: 31285699 PMCID: PMC6587696 DOI: 10.14745/ccdr.v45i04a04] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Of the 3,500 species of mosquitoes worldwide, only a small portion carry and transmit the mosquito-borne diseases (MBDs) that cause approximately half a million deaths annually worldwide. The most common exotic MBDs, such as malaria and dengue, are not currently established in Canada, in part because of our relatively harsh climate; however, this situation could evolve with climate change. Mosquitoes native to Canada may become infected with new pathogens and move into new regions within Canada. In addition, new mosquito species may move into Canada from other countries, and these exotic species may bring exotic MBDs as well. With high levels of international travel, including to locations with exotic MBDs, there will be more travel-acquired cases of MBDs. With climate change, there is the potential for exotic mosquito populations to become established in Canada. There is already a small area of Canada where exotic Aedes mosquitoes have become established although, to date, there is no evidence that these carry any exotic (or already endemic) MBDs. The increased risks of spreading MBDs, or introducing exotic MBDs, will need a careful clinical and public health response. Clinicians will need to maintain a high level of awareness of current trends, to promote mosquito bite prevention strategies, and to know the laboratory tests needed for early detection and when to report laboratory results to public health. Public health efforts will need to focus on ongoing active surveillance, public and professional awareness and mosquito control. Canadians need to be aware of the risks of acquiring exotic MBDs while travelling abroad as well as the risk that they could serve as a potential route of introduction for exotic MBDs into Canada when they return home.
Collapse
Affiliation(s)
- V Ng
- National Microbiology Laboratory, Public Health Agency of Canada, Guelph, ON, St. Hyacinthe, QC and Winnipeg, MB
| | - EE Rees
- National Microbiology Laboratory, Public Health Agency of Canada, Guelph, ON, St. Hyacinthe, QC and Winnipeg, MB
| | - LR Lindsay
- National Microbiology Laboratory, Public Health Agency of Canada, Guelph, ON, St. Hyacinthe, QC and Winnipeg, MB
| | - MA Drebot
- National Microbiology Laboratory, Public Health Agency of Canada, Guelph, ON, St. Hyacinthe, QC and Winnipeg, MB
| | - T Brownstone
- National Microbiology Laboratory, Public Health Agency of Canada, Guelph, ON, St. Hyacinthe, QC and Winnipeg, MB
- Dalla Lana School of Public Health, University of Toronto, Toronto, ON
| | - T Sadeghieh
- National Microbiology Laboratory, Public Health Agency of Canada, Guelph, ON, St. Hyacinthe, QC and Winnipeg, MB
- Department of Population Medicine, University of Guelph, Guelph, ON
| | - SU Khan
- National Microbiology Laboratory, Public Health Agency of Canada, Guelph, ON, St. Hyacinthe, QC and Winnipeg, MB
- Department of Population Medicine, University of Guelph, Guelph, ON
| |
Collapse
|
18
|
Ewing DA, Purse BV, Cobbold CA, Schäfer SM, White SM. Uncovering mechanisms behind mosquito seasonality by integrating mathematical models and daily empirical population data: Culex pipiens in the UK. Parasit Vectors 2019; 12:74. [PMID: 30732629 PMCID: PMC6367758 DOI: 10.1186/s13071-019-3321-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 01/28/2019] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Many mosquito-borne diseases exhibit substantial seasonality, due to strong links between environmental variables and vector and pathogen life-cycles. Further, a range of density-dependent and density-independent biotic and abiotic processes affect the phenology of mosquito populations, with potentially large knock-on effects for vector dynamics and disease transmission. Whilst it is understood that density-independent and density-dependent processes affect seasonal population levels, it is not clear how these interact temporally to shape the population peaks and troughs. Due to this, the paucity of high-resolution data for validation, and the difficulty of parameterizing density-dependent processes, models of vector dynamics may poorly estimate abundances, which has knock-on effects for our ability predict vector-borne disease outbreaks. RESULTS We present a rich dataset describing seasonal abundance patterns of each life stage of Culex pipiens, a widespread vector of West Nile virus, at a field site in southern England in 2015. Abundance of immature stages was measured three times per week, whilst adult traps were run four nights each week. This dataset is integrated with an existing delay-differential equation model predicting Cx. pipiens seasonal abundance to improve understanding of observed seasonal abundance patterns. At our field site, the outcome of our model fitting suggests interspecific predation on mosquito larvae and temperature-dependent larval mortality combine to act as the main sources of population regulation throughout the active season, whilst competition for resources is a relatively small source of larval mortality. CONCLUSIONS The model suggests that density-independent mortality and interspecific predation interact to shape patterns of mosquito seasonal abundance in a permanent aquatic habitat and we propose that competition for resources is likely to be important where periods of high rainfall create transient habitats. Further, we highlight the importance of challenging population abundance models with data from across all life stages of the species of interest if reliable inferences are to be drawn from these models, particularly when considering mosquito control and vector-borne disease transmission.
Collapse
Affiliation(s)
- David A. Ewing
- Centre for Ecology & Hydrology, Benson Lane, Crowmarsh Gifford, Wallingford, OX10 8BB UK
- Department of Mathematics and Statistics, University of Glasgow, University Place, Glasgow, G12 8QQ UK
- Present address: Biomathematics and Statistics Scotland, James Clerk Maxwell Building, Peter Guthrie Tate Road, The King’s Buildings, Edinburgh, EH9 3FD UK
| | - Bethan V. Purse
- Centre for Ecology & Hydrology, Benson Lane, Crowmarsh Gifford, Wallingford, OX10 8BB UK
| | - Christina A. Cobbold
- Department of Mathematics and Statistics, University of Glasgow, University Place, Glasgow, G12 8QQ UK
- The Boyd Orr Centre for Population and Ecosystem Health, University of Glasgow, University Avenue, Glasgow, G12 8QQ UK
| | - Stefanie M. Schäfer
- Centre for Ecology & Hydrology, Benson Lane, Crowmarsh Gifford, Wallingford, OX10 8BB UK
| | - Steven M. White
- Centre for Ecology & Hydrology, Benson Lane, Crowmarsh Gifford, Wallingford, OX10 8BB UK
- The Wolfson Centre for Mathematical Biology, Mathematical Institute, Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG UK
| |
Collapse
|
19
|
Osman MAREN, Li J. Analysis of a vector-bias malaria transmission model with application to Mexico, Sudan and Democratic Republic of the Congo. J Theor Biol 2018; 464:72-84. [PMID: 30586553 DOI: 10.1016/j.jtbi.2018.12.033] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 10/08/2018] [Accepted: 12/22/2018] [Indexed: 01/31/2023]
Abstract
Malaria is a deadly disease transmitted to human through the bite of infected female mosquitoes. The aim of this paper is to study the different vector-bias values between low and high transmission areas with the examples of Mexico (low) and Sudan, Democratic Republic of the Congo (Congo, DR) (high) during malaria transmission. We develop a malaria transmission model with vector-bias and investigate the basic reproduction number, the existence of equilibria and the corresponding globally asymptotically stable. Then, we simulate the reported cases of Mexico and Sudan, Democratic Republic of the Congo by World Health Organization (WHO) (WHO, 0000) and predict the direction of the disease. Our simulation results show that the most endemic country is Congo, DR with the highest vector-bias and R0 values, followed by Sudan and Mexico with less, respectively and that the disease will die out in Mexico and persist in Sudan and Congo, DR. Furthermore, we perform sensitivity analysis of R0 and give some useful comments on reducing the cases of the disease.
Collapse
Affiliation(s)
| | - Jinhui Li
- School of Mathematics and Statistics, Central China Normal University, Wuhan 430079, China.
| |
Collapse
|
20
|
Eikenberry SE, Gumel AB. Mathematical modeling of climate change and malaria transmission dynamics: a historical review. J Math Biol 2018; 77:857-933. [PMID: 29691632 DOI: 10.1007/s00285-018-1229-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 03/16/2018] [Indexed: 12/24/2022]
Abstract
Malaria, one of the greatest historical killers of mankind, continues to claim around half a million lives annually, with almost all deaths occurring in children under the age of five living in tropical Africa. The range of this disease is limited by climate to the warmer regions of the globe, and so anthropogenic global warming (and climate change more broadly) now threatens to alter the geographic area for potential malaria transmission, as both the Plasmodium malaria parasite and Anopheles mosquito vector have highly temperature-dependent lifecycles, while the aquatic immature Anopheles habitats are also strongly dependent upon rainfall and local hydrodynamics. A wide variety of process-based (or mechanistic) mathematical models have thus been proposed for the complex, highly nonlinear weather-driven Anopheles lifecycle and malaria transmission dynamics, but have reached somewhat disparate conclusions as to optimum temperatures for transmission, and the possible effect of increasing temperatures upon (potential) malaria distribution, with some projecting a large increase in the area at risk for malaria, but others predicting primarily a shift in the disease's geographic range. More generally, both global and local environmental changes drove the initial emergence of P. falciparum as a major human pathogen in tropical Africa some 10,000 years ago, and the disease has a long and deep history through the present. It is the goal of this paper to review major aspects of malaria biology, methods for formalizing these into mathematical forms, uncertainties and controversies in proper modeling methodology, and to provide a timeline of some major modeling efforts from the classical works of Sir Ronald Ross and George Macdonald through recent climate-focused modeling studies. Finally, we attempt to place such mathematical work within a broader historical context for the "million-murdering Death" of malaria.
Collapse
Affiliation(s)
- Steffen E Eikenberry
- Global Security Initiative, Arizona State University, Tempe, AZ, USA. .,School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ, USA.
| | - Abba B Gumel
- School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ, USA
| |
Collapse
|
21
|
Mallya S, Sander B, Roy-Gagnon MH, Taljaard M, Jolly A, Kulkarni MA. Factors associated with human West Nile virus infection in Ontario: a generalized linear mixed modelling approach. BMC Infect Dis 2018; 18:141. [PMID: 29587649 PMCID: PMC5872497 DOI: 10.1186/s12879-018-3052-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 03/20/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND West Nile Virus (WNV) is a mosquito-borne pathogen that has become established in North America. Risk for human infection varies geographically in accordance with climate and population factors. Though often asymptomatic, human WNV infection can cause febrile illness or, rarely, neurologic disease. WNV has become a public health concern in Canada since its introduction in 2001. METHODS To identify predictors of human WNV incidence at the public health unit (PHU) level in Ontario, Canada, we combined data on environmental and population characteristics of PHUs with historical mosquito and human surveillance records from 2002 to 2013. We examined the associations between annual WNV incidence and monthly climate indices (e.g. minimum and maximum temperature, average precipitation), land cover (e.g. deciduous forest, water), population structure (e.g. age and sex composition) and the annual percentage of WNV-positive mosquito pools from 2002 to 2013. We then developed a generalized linear mixed model with a Poisson distribution adjusting for spatial autocorrelation and repeat measures. Further to this, to examine potential 'early season' predictors of WNV incidence in a given year, we developed a model based on winter and spring monthly climate indices. RESULTS Several climate indices, including mean minimum temperature (o C) in February (RR = 1.58, CI: [1.42, 1.75]), and the annual percentage of WNV-positive mosquito pools (RR = 1.07, CI: [1.04, 1.11]) were significantly associated with human WNV incidence at the PHU level. Higher winter minimum temperatures were also strongly associated with annual WNV incidence in the 'early season' model (e.g. February minimum temperature (RR = 1.91, CI: [1.73, 2.12]). CONCLUSIONS Our study demonstrates that early season temperature and precipitation indices, in addition to the percentage of WNV-positive mosquito pools in a given area, may assist in predicting the likelihood of a more severe human WNV season in southern regions of Ontario, where WNV epidemics occur sporadically.
Collapse
Affiliation(s)
- Shruti Mallya
- School of Epidemiology & Public Health, University of Ottawa, 600 Peter Morand Cres, Ottawa, ON Canada
| | - Beate Sander
- Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON Canada
- Public Health Ontario, Toronto, ON Canada
- Institute for Clinical and Evaluative Sciences, Toronto, ON Canada
| | - Marie-Hélène Roy-Gagnon
- School of Epidemiology & Public Health, University of Ottawa, 600 Peter Morand Cres, Ottawa, ON Canada
| | - Monica Taljaard
- School of Epidemiology & Public Health, University of Ottawa, 600 Peter Morand Cres, Ottawa, ON Canada
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON Canada
| | - Ann Jolly
- School of Epidemiology & Public Health, University of Ottawa, 600 Peter Morand Cres, Ottawa, ON Canada
| | - Manisha A. Kulkarni
- School of Epidemiology & Public Health, University of Ottawa, 600 Peter Morand Cres, Ottawa, ON Canada
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON Canada
| |
Collapse
|
22
|
Hamlet A, Jean K, Perea W, Yactayo S, Biey J, Van Kerkhove M, Ferguson N, Garske T. The seasonal influence of climate and environment on yellow fever transmission across Africa. PLoS Negl Trop Dis 2018; 12:e0006284. [PMID: 29543798 PMCID: PMC5854243 DOI: 10.1371/journal.pntd.0006284] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 01/30/2018] [Indexed: 11/19/2022] Open
Abstract
Background Yellow fever virus (YFV) is a vector-borne flavivirus endemic to Africa and Latin America. Ninety per cent of the global burden occurs in Africa where it is primarily transmitted by Aedes spp, with Aedes aegypti the main vector for urban yellow fever (YF). Mosquito life cycle and viral replication in the mosquito are heavily dependent on climate, particularly temperature and rainfall. We aimed to assess whether seasonal variations in climatic factors are associated with the seasonality of YF reports. Methodology/Principal findings We constructed a temperature suitability index for YFV transmission, capturing the temperature dependence of mosquito behaviour and viral replication within the mosquito. We then fitted a series of multilevel logistic regression models to a dataset of YF reports across Africa, considering location and seasonality of occurrence for seasonal models, against the temperature suitability index, rainfall and the Enhanced Vegetation Index (EVI) as covariates alongside further demographic indicators. Model fit was assessed by the Area Under the Curve (AUC), and models were ranked by Akaike’s Information Criterion which was used to weight model outputs to create combined model predictions. The seasonal model accurately captured both the geographic and temporal heterogeneities in YF transmission (AUC = 0.81), and did not perform significantly worse than the annual model which only captured the geographic distribution. The interaction between temperature suitability and rainfall accounted for much of the occurrence of YF, which offers a statistical explanation for the spatio-temporal variability in transmission. Conclusions/Significance The description of seasonality offers an explanation for heterogeneities in the West-East YF burden across Africa. Annual climatic variables may indicate a transmission suitability not always reflected in seasonal interactions. This finding, in conjunction with forecasted data, could highlight areas of increased transmission and provide insights into the occurrence of large outbreaks, such as those seen in Angola, the Democratic Republic of the Congo and Brazil. In this article, we describe the development of a model to quantify the seasonal dynamics of yellow fever virus (YFV) transmission across Africa. YFV is a flavivirus transmitted, within Africa, primarily by Aedes spp where it causes an estimated 78,000 deaths a year despite the presence of a safe and effective vaccine. The importance of sufficient vaccination, made difficult by a global shortage, has been highlighted by recent large scale, devastating, outbreaks in Angola, the Democratic Republic of the Congo and Brazil. Here we describe a novel way of parameterising the effect of temperature on YFV transmission and implement statistical models to predict both the geographic and temporal heterogeneities in transmissions, while demonstrating their robustness in comparison to models simply predicting geographic distribution. We believe this quantification of seasonality could lead to more precise applications of vaccination campaigns and vector-control programmes. In turn this would help maximise their impact, especially vital with limited resources, and could contribute to lessening the risk of large scale outbreaks. Not only this, but the methods described here could be applied to other Aedes-borne diseases and as such provide a useful tool in understanding, and combatting, several other important diseases such as dengue and zika.
Collapse
Affiliation(s)
- Arran Hamlet
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
- * E-mail:
| | - Kévin Jean
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
- Laboratoire MESuRS, Conservatoire National des Arts et Métiers, Paris, France
| | - William Perea
- WHO, Infectious Hazard Management, Geneva, Switzerland
| | | | - Joseph Biey
- WHO-AFRO, IST/WA, Ouagadougou, Burkina, Faso
| | - Maria Van Kerkhove
- WHO, Infectious Hazard Management, Geneva, Switzerland
- Centre for Global Health, Institut Pasteur, Paris, France
| | - Neil Ferguson
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Tini Garske
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| |
Collapse
|
23
|
Ohm JR, Baldini F, Barreaux P, Lefevre T, Lynch PA, Suh E, Whitehead SA, Thomas MB. Rethinking the extrinsic incubation period of malaria parasites. Parasit Vectors 2018. [PMID: 29530073 PMCID: PMC5848458 DOI: 10.1186/s13071-018-2761-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The time it takes for malaria parasites to develop within a mosquito, and become transmissible, is known as the extrinsic incubation period, or EIP. EIP is a key parameter influencing transmission intensity as it combines with mosquito mortality rate and competence to determine the number of mosquitoes that ultimately become infectious. In spite of its epidemiological significance, data on EIP are scant. Current approaches to estimate EIP are largely based on temperature-dependent models developed from data collected on parasite development within a single mosquito species in the 1930s. These models assume that the only factor affecting EIP is mean environmental temperature. Here, we review evidence to suggest that in addition to mean temperature, EIP is likely influenced by genetic diversity of the vector, diversity of the parasite, and variation in a range of biotic and abiotic factors that affect mosquito condition. We further demonstrate that the classic approach of measuring EIP as the time at which mosquitoes first become infectious likely misrepresents EIP for a mosquito population. We argue for a better understanding of EIP to improve models of transmission, refine predictions of the possible impacts of climate change, and determine the potential evolutionary responses of malaria parasites to current and future mosquito control tools.
Collapse
Affiliation(s)
- Johanna R Ohm
- Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA, USA.
| | - Francesco Baldini
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, UK
| | - Priscille Barreaux
- Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA, USA
| | - Thierry Lefevre
- MIVEGEC, IRD, CNRS, University of Montpellier, Montpellier, France
| | - Penelope A Lynch
- College of Life and Environmental Sciences, Penryn Campus, University of Exeter, Cornwall, UK
| | - Eunho Suh
- Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA, USA
| | - Shelley A Whitehead
- Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA, USA
| | - Matthew B Thomas
- Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA, USA
| |
Collapse
|
24
|
Laureano-Rosario AE, Duncan AP, Mendez-Lazaro PA, Garcia-Rejon JE, Gomez-Carro S, Farfan-Ale J, Savic DA, Muller-Karger FE. Application of Artificial Neural Networks for Dengue Fever Outbreak Predictions in the Northwest Coast of Yucatan, Mexico and San Juan, Puerto Rico. Trop Med Infect Dis 2018; 3:tropicalmed3010005. [PMID: 30274404 PMCID: PMC6136605 DOI: 10.3390/tropicalmed3010005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/18/2017] [Accepted: 01/02/2018] [Indexed: 11/16/2022] Open
Abstract
Modelling dengue fever in endemic areas is important to mitigate and improve vector-borne disease control to reduce outbreaks. This study applied artificial neural networks (ANNs) to predict dengue fever outbreak occurrences in San Juan, Puerto Rico (USA), and in several coastal municipalities of the state of Yucatan, Mexico, based on specific thresholds. The models were trained with 19 years of dengue fever data for Puerto Rico and six years for Mexico. Environmental and demographic data included in the predictive models were sea surface temperature (SST), precipitation, air temperature (i.e., minimum, maximum, and average), humidity, previous dengue cases, and population size. Two models were applied for each study area. One predicted dengue incidence rates based on population at risk (i.e., numbers of people younger than 24 years), and the other on the size of the vulnerable population (i.e., number of people younger than five years and older than 65 years). The predictive power was above 70% for all four model runs. The ANNs were able to successfully model dengue fever outbreak occurrences in both study areas. The variables with the most influence on predicting dengue fever outbreak occurrences for San Juan, Puerto Rico, included population size, previous dengue cases, maximum air temperature, and date. In Yucatan, Mexico, the most important variables were population size, previous dengue cases, minimum air temperature, and date. These models have predictive skills and should help dengue fever mitigation and management to aid specific population segments in the Caribbean region and around the Gulf of Mexico.
Collapse
Affiliation(s)
- Abdiel E Laureano-Rosario
- Institute for Marine Remote Sensing, University of South Florida, College of Marine Science, 140 7th Avenue South, Saint Petersburg, FL 33701, USA.
| | - Andrew P Duncan
- Centre for Water Systems, University of Exeter, Harrison Building, North Park Road, Exeter EX4 4QF, UK.
| | - Pablo A Mendez-Lazaro
- Environmental Health Department, Graduate School of Public Health, University of Puerto Rico, Medical Sciences Campus, P.O. Box 365067, San Juan, PR 00936, USA.
| | - Julian E Garcia-Rejon
- Centro de Investigaciones Regionales, Lab de Arbovirologia, Unidad Inalámbrica, Universidad Autonoma de Yucatan, Calle 43 No. 613 x Calle 90, Colonia Inalambrica, Merida C.P. 97069, Yucatan, Mexico.
| | - Salvador Gomez-Carro
- Servicios de Salud de Yucatan, Hospital General Agustin O'Horan Unidad de Vigilancia Epidemiologica, Avenida Itzaes s/n Av. Jacinto Canek, Centro, Merida C.P. 97000, Yucatan, Mexico.
| | - Jose Farfan-Ale
- Centro de Investigaciones Regionales, Lab de Arbovirologia, Unidad Inalámbrica, Universidad Autonoma de Yucatan, Calle 43 No. 613 x Calle 90, Colonia Inalambrica, Merida C.P. 97069, Yucatan, Mexico.
| | - Dragan A Savic
- Centre for Water Systems, University of Exeter, Harrison Building, North Park Road, Exeter EX4 4QF, UK.
| | - Frank E Muller-Karger
- Institute for Marine Remote Sensing, University of South Florida, College of Marine Science, 140 7th Avenue South, Saint Petersburg, FL 33701, USA.
| |
Collapse
|
25
|
Wang X, Zhao XQ. A climate-based malaria model with the use of bed nets. J Math Biol 2017; 77:1-25. [PMID: 28965238 DOI: 10.1007/s00285-017-1183-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 05/03/2017] [Indexed: 11/26/2022]
Abstract
Insecticide-treated bed nets (ITNs) are among the most important and effective intervention measures against malaria. In order to investigate the impact of bed net use on disease control, we formulate a periodic vector-bias malaria model incorporating the juvenile stage of mosquitoes and the use of ITNs. We derive the vector reproduction ratio [Formula: see text] and the basic reproduction ratio [Formula: see text]. We show that the global dynamics of the model is completely determined by these two reproduction ratios. More precisely, the mosquito-free periodic solution is globally attractive if [Formula: see text]; the unique disease-free periodic solution is globally attractive if [Formula: see text] and [Formula: see text]; and the model admits a unique positive periodic solution and it is globally attractive if [Formula: see text] and [Formula: see text]. Numerically, we study the malaria transmission case in Port Harcourt, Nigeria. Our findings show that the use of ITNs has a positive effect on reducing [Formula: see text], and that malaria may be eliminated from this area if over 75% of the human population were to use ITNs. The simulation about the long term behavior of solutions has good agreement with the obtained analytic result. Moreover, we find that the ignorance of the vector-bias effect may result in underestimation of the basic reproduction ratio [Formula: see text]. Another notable result is that the infection risk would be underestimated if the basic reproduction ratio [Formula: see text] of the time-averaged autonomous system were used.
Collapse
Affiliation(s)
- Xiunan Wang
- Department of Mathematics and Statistics, Memorial University of Newfoundland, St. John's, NL, A1C 5S7, Canada.
| | - Xiao-Qiang Zhao
- Department of Mathematics and Statistics, Memorial University of Newfoundland, St. John's, NL, A1C 5S7, Canada
| |
Collapse
|
26
|
Pergantas P, Tsatsaris A, Malesios C, Kriparakou G, Demiris N, Tselentis Y. A spatial predictive model for malaria resurgence in central Greece integrating entomological, environmental and social data. PLoS One 2017; 12:e0178836. [PMID: 28662158 PMCID: PMC5490999 DOI: 10.1371/journal.pone.0178836] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 05/19/2017] [Indexed: 01/17/2023] Open
Abstract
Malaria constitutes an important cause of human mortality. After 2009 Greece experienced a resurgence of malaria. Here, we develop a model-based framework that integrates entomological, geographical, social and environmental evidence in order to guide the mosquito control efforts and apply this framework to data from an entomological survey study conducted in Central Greece. Our results indicate that malaria transmission risk in Greece is potentially substantial. In addition, specific districts such as seaside, lakeside and rice field regions appear to represent potential malaria hotspots in Central Greece. We found that appropriate maps depicting the basic reproduction number, R0, are useful tools for informing policy makers on the risk of malaria resurgence and can serve as a guide to inform recommendations regarding control measures.
Collapse
Affiliation(s)
| | - Andreas Tsatsaris
- Technological Educational Institute of Athens, Department of Department of Civil, Surveying and Geoinformatics Engineering, Athens, Greece
| | - Chrisovalantis Malesios
- Democritus University of Thrace, Department of Rural Development, Orestiada, Greece
- * E-mail:
| | | | - Nikolaos Demiris
- Athens University of Economics and Business, Department of Statistics, Athens, Greece
| | - Yiannis Tselentis
- University of Crete, Regional Public Health Laboratory, Faculty of Medicine, Heraklion, Greece
| |
Collapse
|
27
|
Abiodun GJ, Witbooi P, Okosun KO. Modeling and analyzing the impact of temperature and rainfall on mosquito population dynamics over Kwazulu-Natal, South Africa. INT J BIOMATH 2017. [DOI: 10.1142/s1793524517500553] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Malaria parasites are strongly dependent on Anopheles mosquitoes for transmission; for this reason, mosquito population dynamics are a crucial determinant of malaria risk. However, temperature and rainfall play a significant role in both aquatic and adult stages of the Anopheles. Consequently, it is important to understand the biology of malaria vector mosquitoes in the study of malaria transmission. In this study, we develop a climate-based, ordinary-differential-equation model to analyze how rainfall and temperature determine mosquito population size. In the model, we consider in detail the influence of ambient temperature on gonotrophic and sporogonic cycles over Amajuba District, Kwazulu-Natal Province, South Africa. In particular, we further use the model to simulate the spatial distribution of the mosquito biting rate over the study region. Our results reflect high seasonality of the population of An. gambiae over the region and also demonstrate the influence of climatic factors on the mosquito population dynamics.
Collapse
Affiliation(s)
- Gbenga J. Abiodun
- Department of Mathematics and Applied Mathematics, University of the Western Cape, Private Bag X17, Bellville 7535, Republic of South Africa
| | - Peter Witbooi
- Department of Mathematics and Applied Mathematics, University of the Western Cape, Private Bag X17, Bellville 7535, Republic of South Africa
| | - Kazeem O. Okosun
- Department of Mathematics, Vaal University of Technology, Private Bag X021, Vanderbijlpark, Andries Potgieter Blvrd-1900, Republic of South Africa
| |
Collapse
|
28
|
Shragai T, Tesla B, Murdock C, Harrington LC. Zika and chikungunya: mosquito-borne viruses in a changing world. Ann N Y Acad Sci 2017; 1399:61-77. [PMID: 28187236 DOI: 10.1111/nyas.13306] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Revised: 11/21/2016] [Accepted: 12/02/2016] [Indexed: 12/16/2022]
Abstract
The reemergence and growing burden of mosquito-borne virus infections have incited public fear and growing research efforts to understand the mechanisms of infection-associated health outcomes and to provide better approaches for mosquito vector control. While efforts to develop therapeutics, vaccines, and novel genetic mosquito-control technologies are underway, many important underlying ecological questions remain that could significantly enhance our understanding and ability to predict and prevent transmission. Here, we review the current knowledge about the transmission ecology of two recent arbovirus invaders, the chikungunya and Zika viruses. We introduce the viruses and mosquito vectors, highlighting viral biology, historical routes of transmission, and viral mechanisms facilitating rapid global invasion. In addition, we review factors contributing to vector global invasiveness and transmission efficiency. We conclude with a discussion of how human-induced biotic and abiotic environmental changes facilitate mosquito-borne virus transmission, emphasizing critical gaps in understanding. These knowledge gaps are tremendous; much of our data on basic mosquito ecology in the field predate 1960, and the mosquitoes themselves, as well as the world they live in, have substantially changed. A concerted investment in understanding the basic ecology of these vectors, which serve as the main drivers of pathogen transmission in both wildlife and human populations, is now more important than ever.
Collapse
Affiliation(s)
- Talya Shragai
- Department of Entomology, Cornell University, Ithaca, New York
| | - Blanka Tesla
- Department of Infectious Diseases and Odum School of Ecology, University of Georgia, Athens, Georgia
| | - Courtney Murdock
- Department of Infectious Diseases and Odum School of Ecology, University of Georgia, Athens, Georgia
| | | |
Collapse
|
29
|
Rawal R, Vijay S, Kadian K, Singh J, Pande V, Sharma A. Towards a Proteomic Catalogue and Differential Annotation of Salivary Gland Proteins in Blood Fed Malaria Vector Anopheles culicifacies by Mass Spectrometry. PLoS One 2016; 11:e0161870. [PMID: 27602567 PMCID: PMC5014347 DOI: 10.1371/journal.pone.0161870] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 08/13/2016] [Indexed: 01/09/2023] Open
Abstract
In order to understand the importance of functional proteins in mosquito behavior, following blood meal, a baseline proteomic dataset is essential for providing insights into the physiology of blood feeding. Therefore, in this study as first step, in solution and 1-D electrophoresis digestion approach combined with tandem mass spectrometry (nano LC-MS/MS) and computational bioinformatics for data mining was used to prepare a baseline proteomic catalogue of salivary gland proteins of sugar fed An. culicifacies mosquitoes. A total of 106 proteins were identified and analyzed by SEQUEST algorithm against mosquito protein database from Uniprot/NCBI. Importantly, D7r1, D7r2, D7r4, salivary apyrase, anti-platelet protein, calreticulin, antigen 5 family proteins were identified and grouped on the basis of biological and functional roles. Secondly, differential protein expression and annotations between salivary glands of sugar fed vs blood fed mosquitoes was analyzed using 2-Delectrophoresis combined with MALDI-TOF mass spectrometry. The alterations in the differential expression of total 38 proteins was observed out of which 29 proteins like beclin-1, phosphorylating proteins, heme oxygenase 1, ferritin, apoptotic proteins, coagulation and immunity like, serine proteases, serpins, c-type lectin and protein in regulation of blood feeding behavior were found to be up regulated while 9 proteins related to blood feeding, juvenile hormone epoxide hydrolase ii, odorant binding proteins and energy metabolic enzymes were found to be down regulated. To our knowledge, this study provides a first time baseline proteomic dataset and functional annotations of An. culicifacies salivary gland proteins that may be involved during the blood feeding. Identification of differential salivary proteins between sugar fed and blood fed mosquitoes and their plausible role may provide insights into the physiological processes associated with feeding behavior and sporozoite transmission during the process of blood feeding.
Collapse
Affiliation(s)
- Ritu Rawal
- Protein Biochemistry and Structural Biology, National Institute of Malaria Research (ICMR), Sector-8, Dwarka, New Delhi, India
| | - Sonam Vijay
- Protein Biochemistry and Structural Biology, National Institute of Malaria Research (ICMR), Sector-8, Dwarka, New Delhi, India
| | - Kavita Kadian
- Protein Biochemistry and Structural Biology, National Institute of Malaria Research (ICMR), Sector-8, Dwarka, New Delhi, India
| | - Jagbir Singh
- Protein Biochemistry and Structural Biology, National Institute of Malaria Research (ICMR), Sector-8, Dwarka, New Delhi, India
| | - Veena Pande
- Department of Biotechnology, Kumaun University, Nainital, Uttarakhand, 263001, India
| | - Arun Sharma
- Protein Biochemistry and Structural Biology, National Institute of Malaria Research (ICMR), Sector-8, Dwarka, New Delhi, India
- * E-mail:
| |
Collapse
|
30
|
Assessing the Role of Climate Change in Malaria Transmission in Africa. Malar Res Treat 2016; 2016:7104291. [PMID: 27066290 PMCID: PMC4811621 DOI: 10.1155/2016/7104291] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 01/22/2016] [Accepted: 02/23/2016] [Indexed: 11/18/2022] Open
Abstract
The sensitivity of vector borne diseases like malaria to climate continues to raise considerable concern over the implications of climate change on future disease dynamics. The problem of malaria vectors shifting from their traditional locations to invade new zones is of important concern. A mathematical model incorporating rainfall and temperature is constructed to study the transmission dynamics of malaria. The reproduction number obtained is applied to gridded temperature and rainfall datasets for baseline climate and future climate with aid of GIS. As a result of climate change, malaria burden is likely to increase in the tropics, the highland regions, and East Africa and along the northern limit of falciparum malaria. Falciparum malaria will spread into the African highlands; however it is likely to die out at the southern limit of the disease.
Collapse
|
31
|
O’Regan SM, Lillie JW, Drake JM. Leading indicators of mosquito-borne disease elimination. THEOR ECOL-NETH 2015; 9:269-286. [PMID: 27512522 PMCID: PMC4960289 DOI: 10.1007/s12080-015-0285-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 11/12/2015] [Indexed: 12/03/2022]
Abstract
Mosquito-borne diseases contribute significantly to the global disease burden. High-profile elimination campaigns are currently underway for many parasites, e.g., Plasmodium spp., the causal agent of malaria. Sustaining momentum near the end of elimination programs is often difficult to achieve and consequently quantitative tools that enable monitoring the effectiveness of elimination activities after the initial reduction of cases has occurred are needed. Documenting progress in vector-borne disease elimination is a potentially important application for the theory of critical transitions. Non-parametric approaches that are independent of model-fitting would advance infectious disease forecasting significantly. In this paper, we consider compartmental Ross-McDonald models that are slowly forced through a critical transition through gradually deployed control measures. We derive expressions for the behavior of candidate indicators, including the autocorrelation coefficient, variance, and coefficient of variation in the number of human cases during the approach to elimination. We conducted a simulation study to test the performance of each summary statistic as an early warning system of mosquito-borne disease elimination. Variance and coefficient of variation were highly predictive of elimination but autocorrelation performed poorly as an indicator in some control contexts. Our results suggest that tipping points (bifurcations) in mosquito-borne infectious disease systems may be foreshadowed by characteristic temporal patterns of disease prevalence.
Collapse
Affiliation(s)
- Suzanne M. O’Regan
- Odum School of Ecology, University of Georgia, Athens, GA 30602-2202 USA
- National Institute for Mathematical and Biological Synthesis (NIMBioS), 1122 Volunteer Boulevard, University of Tennessee, Knoxville, TN 37996-3410 USA
| | | | - John M. Drake
- Odum School of Ecology, University of Georgia, Athens, GA 30602-2202 USA
| |
Collapse
|
32
|
Parham PE, Waldock J, Christophides GK, Hemming D, Agusto F, Evans KJ, Fefferman N, Gaff H, Gumel A, LaDeau S, Lenhart S, Mickens RE, Naumova EN, Ostfeld RS, Ready PD, Thomas MB, Velasco-Hernandez J, Michael E. Climate, environmental and socio-economic change: weighing up the balance in vector-borne disease transmission. Philos Trans R Soc Lond B Biol Sci 2015; 370:rstb.2013.0551. [PMID: 25688012 DOI: 10.1098/rstb.2013.0551] [Citation(s) in RCA: 143] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Arguably one of the most important effects of climate change is the potential impact on human health. While this is likely to take many forms, the implications for future transmission of vector-borne diseases (VBDs), given their ongoing contribution to global disease burden, are both extremely important and highly uncertain. In part, this is owing not only to data limitations and methodological challenges when integrating climate-driven VBD models and climate change projections, but also, perhaps most crucially, to the multitude of epidemiological, ecological and socio-economic factors that drive VBD transmission, and this complexity has generated considerable debate over the past 10-15 years. In this review, we seek to elucidate current knowledge around this topic, identify key themes and uncertainties, evaluate ongoing challenges and open research questions and, crucially, offer some solutions for the field. Although many of these challenges are ubiquitous across multiple VBDs, more specific issues also arise in different vector-pathogen systems.
Collapse
Affiliation(s)
- Paul E Parham
- Department of Public Health and Policy, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 3GL, UK Grantham Institute for Climate Change, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, St Mary's Campus, London W2 1PG, UK
| | - Joanna Waldock
- The Cyprus Institute, Nicosia, Cyprus Imperial College London, London SW7 2AZ, UK
| | | | - Deborah Hemming
- Meteorological Office Hadley Centre, UK Meteorological Office, Fitzroy Road, Exeter, EX1 3PB, UK
| | - Folashade Agusto
- Department of Mathematics, Austin Peay State University, Clarksville, TN 37044, USA
| | - Katherine J Evans
- Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831, USA
| | - Nina Fefferman
- Department of Ecology, Evolution and Natural Resources, Rutgers University, New Brunswick, NJ 08901, USA
| | - Holly Gaff
- Department of Biological Sciences, Old Dominium University, Norfolk, VA 23529, USA
| | - Abba Gumel
- Simon A. Levin Mathematical, Computational and Modeling Sciences Center, Arizona State University, Tempe, AZ 85287-1904, USA School of Mathematical and Natural Sciences, Arizona State University, Phoenix, AZ 85069-7100, USA
| | - Shannon LaDeau
- Cary Institute of Ecosystem Studies, PO Box AB, Millbrook, NY 12545-0129, USA
| | - Suzanne Lenhart
- Department of Mathematics, University of Tennessee, Knoxville, TN 37996-1300, USA
| | - Ronald E Mickens
- Department of Physics, Clark Atlanta University, PO Box 172, Atlanta, GA 30314, USA
| | - Elena N Naumova
- Department of Civil and Environmental Engineering, Tufts University School of Engineering, Medford, MA 02155, USA
| | - Richard S Ostfeld
- Cary Institute of Ecosystem Studies, PO Box AB, Millbrook, NY 12545-0129, USA
| | - Paul D Ready
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Matthew B Thomas
- Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA
| | - Jorge Velasco-Hernandez
- Universidad Nacional Autnoma de Mexico Institute of Mathematics Mexico City, Distrito Federal, Mexico
| | - Edwin Michael
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556-0369, USA
| |
Collapse
|
33
|
Christiansen-Jucht CD, Parham PE, Saddler A, Koella JC, Basáñez MG. Larval and adult environmental temperatures influence the adult reproductive traits of Anopheles gambiae s.s. Parasit Vectors 2015; 8:456. [PMID: 26382035 PMCID: PMC4573685 DOI: 10.1186/s13071-015-1053-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 08/19/2015] [Indexed: 01/10/2023] Open
Abstract
Background Anopheles mosquito life-history parameters and population dynamics strongly influence malaria transmission, and environmental factors, particularly temperature, strongly affect these parameters. There are currently some studies on how temperature affects Anopheles gambiae s.s. survival but very few exist examining other life-history traits. We investigate here the effect of temperature on population dynamics parameters. Methods Anopheles gambiae s.s. immatures were reared individually at 23 ± 1 °C, 27 ± 1 °C, 31 ± 1 °C, and 35 ± 1 °C, and adults were held at their larval temperature or at one of the other temperatures. Larvae were checked every 24 h for development to the next stage and measured for size; wing length was measured as a proxy for adult size. Females were blood fed three times, and the number of females feeding and laying eggs was counted. The numbers of eggs and percentage of eggs hatched were recorded. Results Increasing temperatures during the larval stages resulted in significantly smaller larvae (p = 0.005) and smaller adults (p < 0.001). Adult temperature had no effect on the time to egg laying, and the larval temperature of adults only affected the incubation period of the first egg batch. Temperature influenced the time to hatching of eggs, as well as the time to development at every stage. The number of eggs laid was highest when adults were kept at 27 °C, and lowest at 31 °C, and higher adult temperatures decreased the proportion of eggs hatching after the second and third blood meal. Higher adult temperatures significantly decreased the probability of blood feeding, but the larval temperature of adults had no influence on the probability of taking a blood meal. Differences were observed between the first, second, and third blood meal in the times to egg laying and hatching, number of eggs laid, and probabilities of feeding and laying eggs. Conclusions Our study shows that environmental temperature during the larval stages as well as during the adult stages affects Anopheles life-history parameters. Data on how temperature and other climatic factors affect vector life-history parameters are necessary to parameterise more reliably models predicting how global warming may influence malaria transmission. Electronic supplementary material The online version of this article (doi:10.1186/s13071-015-1053-5) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Céline D Christiansen-Jucht
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, Norfolk Place, London, W2 1PG, UK.
| | - Paul E Parham
- Department of Public Health and Policy, Faculty of Health and Life Sciences, University of Liverpool, 33 Finsbury Square, London, EC2A 1AG, UK.
| | - Adam Saddler
- Department of Epidemiology and Public Health, Health Interventions Unit, Swiss TPH, Basel, Switzerland.
| | - Jacob C Koella
- Faculté des Sciences, Institut de Biologie, Université de Neuchâtel, Rue Emile-Argand 11, CH-2000, Neuchâtel, Switzerland.
| | - María-Gloria Basáñez
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, Norfolk Place, London, W2 1PG, UK.
| |
Collapse
|
34
|
Pollitt LC, Bram JT, Blanford S, Jones MJ, Read AF. Existing Infection Facilitates Establishment and Density of Malaria Parasites in Their Mosquito Vector. PLoS Pathog 2015; 11:e1005003. [PMID: 26181518 PMCID: PMC4504473 DOI: 10.1371/journal.ppat.1005003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 06/04/2015] [Indexed: 02/06/2023] Open
Abstract
Very little is known about how vector-borne pathogens interact within their vector and how this impacts transmission. Here we show that mosquitoes can accumulate mixed strain malaria infections after feeding on multiple hosts. We found that parasites have a greater chance of establishing and reach higher densities if another strain is already present in a mosquito. Mixed infections contained more parasites but these larger populations did not have a detectable impact on vector survival. Together these results suggest that mosquitoes taking multiple infective bites may disproportionally contribute to malaria transmission. This will increase rates of mixed infections in vertebrate hosts, with implications for the evolution of parasite virulence and the spread of drug-resistant strains. Moreover, control measures that reduce parasite prevalence in vertebrate hosts will reduce the likelihood of mosquitoes taking multiple infective feeds, and thus disproportionally reduce transmission. More generally, our study shows that the types of strain interactions detected in vertebrate hosts cannot necessarily be extrapolated to vectors.
Collapse
Affiliation(s)
- Laura C. Pollitt
- Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
- Center for Infectious Disease Dynamics, Departments of Biology and Entomology, Pennsylvania State University, State College, Pennsylvania, United States of America
- * E-mail:
| | - Joshua T. Bram
- Center for Infectious Disease Dynamics, Departments of Biology and Entomology, Pennsylvania State University, State College, Pennsylvania, United States of America
| | - Simon Blanford
- Center for Infectious Disease Dynamics, Departments of Biology and Entomology, Pennsylvania State University, State College, Pennsylvania, United States of America
| | - Matthew J. Jones
- Center for Infectious Disease Dynamics, Departments of Biology and Entomology, Pennsylvania State University, State College, Pennsylvania, United States of America
| | - Andrew F. Read
- Center for Infectious Disease Dynamics, Departments of Biology and Entomology, Pennsylvania State University, State College, Pennsylvania, United States of America
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
| |
Collapse
|
35
|
LaDeau SL, Allan BF, Leisnham PT, Levy MZ. The ecological foundations of transmission potential and vector-borne disease in urban landscapes. Funct Ecol 2015; 29:889-901. [PMID: 26549921 PMCID: PMC4631442 DOI: 10.1111/1365-2435.12487] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Urban transmission of arthropod-vectored disease has increased in recent decades. Understanding and managing transmission potential in urban landscapes requires integration of sociological and ecological processes that regulate vector population dynamics, feeding behavior, and vector-pathogen interactions in these unique ecosystems. Vectorial capacity is a key metric for generating predictive understanding about transmission potential in systems with obligate vector transmission. This review evaluates how urban conditions, specifically habitat suitability and local temperature regimes, and the heterogeneity of urban landscapes can influence the biologically-relevant parameters that define vectorial capacity: vector density, survivorship, biting rate, extrinsic incubation period, and vector competence.Urban landscapes represent unique mosaics of habitat. Incidence of vector-borne disease in urban host populations is rarely, if ever, evenly distributed across an urban area. The persistence and quality of vector habitat can vary significantly across socio-economic boundaries to influence vector species composition and abundance, often generating socio-economically distinct gradients of transmission potential across neighborhoods.Urban regions often experience unique temperature regimes, broadly termed urban heat islands (UHI). Arthropod vectors are ectothermic organisms and their growth, survival, and behavior are highly sensitive to environmental temperatures. Vector response to UHI conditions is dependent on regional temperature profiles relative to the vector's thermal performance range. In temperate climates UHI can facilitate increased vector development rates while having countervailing influence on survival and feeding behavior. Understanding how urban heat island (UHI) conditions alter thermal and moisture constraints across the vector life cycle to influence transmission processes is an important direction for both empirical and modeling research.There remain persistent gaps in understanding of vital rates and drivers in mosquito-vectored disease systems, and vast holes in understanding for other arthropod vectored diseases. Empirical studies are needed to better understand the physiological constraints and socio-ecological processes that generate heterogeneity in critical transmission parameters, including vector survival and fitness. Likewise, laboratory experiments and transmission models must evaluate vector response to realistic field conditions, including variability in sociological and environmental conditions.
Collapse
Affiliation(s)
| | - Brian F. Allan
- Department of Entomology, University of Illinois, Urbana, IL, USA
| | - Paul T. Leisnham
- Concentration in Ecosystem Health and Natural Resource Management, Department of Environmental Science & Technology, University of Maryland, College Park, MD, USA
| | - Michael Z. Levy
- Department of Biostatistics & Epidemiology, University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|
36
|
Sternberg ED, Thomas MB. Local adaptation to temperature and the implications for vector-borne diseases. Trends Parasitol 2014; 30:115-22. [DOI: 10.1016/j.pt.2013.12.010] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 12/24/2013] [Accepted: 12/28/2013] [Indexed: 12/29/2022]
|