1
|
Joseph D, Ramachandran R, Alzabut J, Jose SA, Khan H. A Fractional-Order Density-Dependent Mathematical Model to Find the Better Strain of Wolbachia. Symmetry (Basel) 2023. [DOI: 10.3390/sym15040845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023] Open
Abstract
The primary objective of the current study was to create a mathematical model utilizing fractional-order calculus for the purpose of analyzing the symmetrical characteristics of Wolbachia dissemination among Aedesaegypti mosquitoes. We investigated various strains of Wolbachia to determine the most sustainable one through predicting their dynamics. Wolbachia is an effective tool for controlling mosquito-borne diseases, and several strains have been tested in laboratories and released into outbreak locations. This study aimed to determine the symmetrical features of the most efficient strain from a mathematical perspective. This was accomplished by integrating a density-dependent death rate and the rate of cytoplasmic incompatibility (CI) into the model to examine the spread of Wolbachia and non-Wolbachia mosquitoes. The fractional-order mathematical model developed here is physically meaningful and was assessed for equilibrium points in the presence and absence of disease. Eight equilibrium points were determined, and their local and global stability were determined using the Routh–Hurwitz criterion and linear matrix inequality theory. The basic reproduction number was calculated using the next-generation matrix method. The research also involved conducting numerical simulations to evaluate the behavior of the basic reproduction number for different equilibrium points and identify the optimal CI value for reducing disease spread.
Collapse
Affiliation(s)
- Dianavinnarasi Joseph
- Centre for Nonlinear Systems, Chennai Institute of Technology, Chennai 600069, Tamil Nadu, India
| | - Raja Ramachandran
- Ramanujan Centre for Higher Mathematics, Alagappa University, Karaikudi 630004, India
- Department of Computer Science and Mathematics, Lebanese American University, Beirut 1102-2801, Lebanon
| | - Jehad Alzabut
- Department of Mathematics and Sciences, Prince Sultan University, Riyadh 11586, Saudi Arabia
- Department of Industrial Engineering, OSTIM Technical University, Ankara 06374, Turkey
| | - Sayooj Aby Jose
- Department of Mathematics, Alagappa University, Karaikudi 630004, India
- School of Mathematics & Statistics, Mahatma Gandhi University, Kottayam 686560, Kerala, India
| | - Hasib Khan
- Department of Mathematics and Sciences, Prince Sultan University, Riyadh 11586, Saudi Arabia
- Department of Mathematics, Shaheed Benazir Bhutto University Sheringal Dir Upper, Khyber Pakhtunkhwa 18000, Pakistan
| |
Collapse
|
2
|
Ogunlade ST, Adekunle AI, McBryde ES, Meehan MT. Modelling the ecological dynamics of mosquito populations with multiple co-circulating Wolbachia strains. Sci Rep 2022; 12:20826. [PMID: 36460676 PMCID: PMC9718785 DOI: 10.1038/s41598-022-25242-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 11/28/2022] [Indexed: 12/03/2022] Open
Abstract
Wolbachia intracellular bacteria successfully reduce the transmissibility of arthropod-borne viruses (arboviruses) when introduced into virus-carrying vectors such as mosquitoes. Despite the progress made by introducing Wolbachia bacteria into the Aedes aegypti wild-type population to control arboviral infections, reports suggest that heat-induced loss-of-Wolbachia-infection as a result of climate change may reverse these gains. Novel, supplemental Wolbachia strains that are more resilient to increased temperatures may circumvent these concerns, and could potentially act synergistically with existing variants. In this article, we model the ecological dynamics among three distinct mosquito (sub)populations: a wild-type population free of any Wolbachia infection; an invading population infected with a particular Wolbachia strain; and a second invading population infected with a distinct Wolbachia strain from that of the first invader. We explore how the range of possible characteristics of each Wolbachia strain impacts mosquito prevalence. Further, we analyse the differential system governing the mosquito populations and the Wolbachia infection dynamics by computing the full set of basic and invasive reproduction numbers and use these to establish stability of identified equilibria. Our results show that releasing mosquitoes with two different strains of Wolbachia did not increase their prevalence, compared with a single-strain Wolbachia-infected mosquito introduction and only delayed Wolbachia dominance.
Collapse
Affiliation(s)
- Samson T. Ogunlade
- grid.1011.10000 0004 0474 1797Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, QLD Australia ,grid.1011.10000 0004 0474 1797College of Medicine and Dentistry, James Cook University, Townsville, QLD Australia
| | - Adeshina I. Adekunle
- grid.1011.10000 0004 0474 1797Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, QLD Australia ,grid.431245.50000 0004 0385 5290Department of Defence, Defence Science and Technology Group, Melbourne, VIC Australia
| | - Emma S. McBryde
- grid.1011.10000 0004 0474 1797Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, QLD Australia
| | - Michael T. Meehan
- grid.1011.10000 0004 0474 1797Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, QLD Australia
| |
Collapse
|
3
|
Aguiar M, Anam V, Blyuss KB, Estadilla CDS, Guerrero BV, Knopoff D, Kooi BW, Srivastav AK, Steindorf V, Stollenwerk N. Mathematical models for dengue fever epidemiology: A 10-year systematic review. Phys Life Rev 2022; 40:65-92. [PMID: 35219611 PMCID: PMC8845267 DOI: 10.1016/j.plrev.2022.02.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 02/08/2022] [Indexed: 01/11/2023]
Abstract
Mathematical models have a long history in epidemiological research, and as the COVID-19 pandemic progressed, research on mathematical modeling became imperative and very influential to understand the epidemiological dynamics of disease spreading. Mathematical models describing dengue fever epidemiological dynamics are found back from 1970. Dengue fever is a viral mosquito-borne infection caused by four antigenically related but distinct serotypes (DENV-1 to DENV-4). With 2.5 billion people at risk of acquiring the infection, it is a major international public health concern. Although most of the cases are asymptomatic or mild, the disease immunological response is complex, with severe disease linked to the antibody-dependent enhancement (ADE) - a disease augmentation phenomenon where pre-existing antibodies to previous dengue infection do not neutralize but rather enhance the new infection. Here, we present a 10-year systematic review on mathematical models for dengue fever epidemiology. Specifically, we review multi-strain frameworks describing host-to-host and vector-host transmission models and within-host models describing viral replication and the respective immune response. Following a detailed literature search in standard scientific databases, different mathematical models in terms of their scope, analytical approach and structural form, including model validation and parameter estimation using empirical data, are described and analyzed. Aiming to identify a consensus on infectious diseases modeling aspects that can contribute to public health authorities for disease control, we revise the current understanding of epidemiological and immunological factors influencing the transmission dynamics of dengue. This review provide insights on general features to be considered to model aspects of real-world public health problems, such as the current epidemiological scenario we are living in.
Collapse
Affiliation(s)
- Maíra Aguiar
- Basque Center for Applied Mathematics, Alameda de Mazarredo 14, Bilbao, E-48009, Basque Country, Spain; Dipartimento di Matematica, Università degli Studi di Trento, Via Sommarive 14, Povo, Trento, 38123, Italy; Ikerbasque, Basque Foundation for Science, Bilbao, Spain.
| | - Vizda Anam
- Basque Center for Applied Mathematics, Alameda de Mazarredo 14, Bilbao, E-48009, Basque Country, Spain
| | - Konstantin B Blyuss
- VU University, Faculty of Science, De Boelelaan 1085, NL 1081, HV Amsterdam, the Netherlands
| | - Carlo Delfin S Estadilla
- Basque Center for Applied Mathematics, Alameda de Mazarredo 14, Bilbao, E-48009, Basque Country, Spain
| | - Bruno V Guerrero
- Basque Center for Applied Mathematics, Alameda de Mazarredo 14, Bilbao, E-48009, Basque Country, Spain
| | - Damián Knopoff
- Basque Center for Applied Mathematics, Alameda de Mazarredo 14, Bilbao, E-48009, Basque Country, Spain; Centro de Investigaciones y Estudios de Matemática CIEM, CONICET, Medina Allende s/n, Córdoba, 5000, Argentina
| | - Bob W Kooi
- University of Sussex, Department of Mathematics, Falmer, Brighton, UK
| | - Akhil Kumar Srivastav
- Basque Center for Applied Mathematics, Alameda de Mazarredo 14, Bilbao, E-48009, Basque Country, Spain
| | - Vanessa Steindorf
- Basque Center for Applied Mathematics, Alameda de Mazarredo 14, Bilbao, E-48009, Basque Country, Spain
| | - Nico Stollenwerk
- Basque Center for Applied Mathematics, Alameda de Mazarredo 14, Bilbao, E-48009, Basque Country, Spain; Dipartimento di Matematica, Università degli Studi di Trento, Via Sommarive 14, Povo, Trento, 38123, Italy
| |
Collapse
|
4
|
Local and Global Stability Analysis of Dengue Disease with Vaccination and Optimal Control. Symmetry (Basel) 2021. [DOI: 10.3390/sym13101917] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Dengue fever is a disease that has spread all over the world, including Thailand. Dengue is caused by a virus and there are four distinct serotypes of the virus that cause dengue DENV-1, DENV-2, DENV-3, and DENV-4. The dengue viruses are transmitted by two species of the Aedes mosquitoes, the Aedes aegypti, and the Aedes albopictus. Currently, the dengue vaccine used in Thailand is chimeric yellow tetravalent dengue (CYD-TDV). This research presents optimal control which studies the vaccination only in individuals with a documented past dengue infection (seropositive), regardless of the serotypes of infection causing the initial infection by the disease. The analysis of dengue transmission model is used to establish the local asymptotically stabilities. The property of symmetry in the Lyapunov function an import role in achieving this global asymptotically stabilities. The optimal control systems are shown in numerical solutions and conclusions. The result shows that the control resulted in a significant reduction in the number of infected humans and infected vectors.
Collapse
|
5
|
Ndii MZ, Mage AR, Messakh JJ, Djahi BS. Optimal vaccination strategy for dengue transmission in Kupang city, Indonesia. Heliyon 2020; 6:e05345. [PMID: 33204872 PMCID: PMC7648192 DOI: 10.1016/j.heliyon.2020.e05345] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 06/24/2020] [Accepted: 10/22/2020] [Indexed: 11/22/2022] Open
Abstract
Dengue is a public health problem with around 390 million cases annually and is caused by four distinct serotypes. Infection by one of the serotypes provides lifelong immunity to that serotype but have a higher chance of attracting the more dangerous forms of dengue in subsequent infections. Therefore, a perfect strategy against dengue is required. Dengue vaccine with 42-80% efficacy level has been licensed for the use in reducing disease transmission. However, this may increase the likelihood of obtaining the dangerous forms of dengue. In this paper, we have developed single and two-serotype dengue mathematical models to investigate the effects of vaccination on dengue transmission dynamics. The model is validated against dengue data from Kupang city, Indonesia. We investigate the effects of vaccination on seronegative and seropositive individuals and perform a global sensitivity analysis to determine the most influential parameters of the model. A sensitivity analysis suggests that the vaccination rate, the transmission probability and the biting rate have greater effects on the reduction of the proportion of dengue cases. Interestingly, with vaccine implementation, the mosquito-related parameters do not have significant impact on the reduction in the proportion of dengue cases. If the vaccination is implemented on seronegative individuals only, it may increase the likelihood of obtaining the severe dengue. To reduce the proportion of severe dengue cases, it is better to vaccinate seropositive individuals. In the context of Kupang City where the majority of individuals have been infected by at least one dengue serotype, the implementation of vaccination strategy is possible. However, understanding the serotype-specific differences is required to optimise the delivery of the intervention.
Collapse
Affiliation(s)
- Meksianis Z Ndii
- Department of Mathematics, The University of Nusa Cendana, Kupang-NTT, Indonesia
| | - Ananda R Mage
- Department of Mathematics, The University of Nusa Cendana, Kupang-NTT, Indonesia
| | - Jakobis J Messakh
- Department of Building Engineering Education, The University of Nusa Cendana, Kupang-NTT, Indonesia
| | - Bertha S Djahi
- Department of Computer Science, The University of Nusa Cendana, Kupang-NTT, Indonesia
| |
Collapse
|
6
|
Ogunlade ST, Adekunle AI, Meehan MT, Rojas DP, McBryde ES. Modeling the potential of wAu-Wolbachia strain invasion in mosquitoes to control Aedes-borne arboviral infections. Sci Rep 2020; 10:16812. [PMID: 33033285 PMCID: PMC7544821 DOI: 10.1038/s41598-020-73819-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 09/22/2020] [Indexed: 12/18/2022] Open
Abstract
Arboviral infections such as dengue, Zika and chikungunya are fast spreading diseases that pose significant health problems globally. In order to control these infections, an intracellular bacterium called Wolbachia has been introduced into wild-type mosquito populations in the hopes of replacing the vector transmitting agent, Aedes aegypti with one that is incapable of transmission. In this study, we developed a Wolbachia transmission model for the novel wAu strain which possesses several favourable traits (e.g., enhanced viral blockage and maintenance at higher temperature) but not cyctoplasmic incompatibility (CI)-when a Wolbachia-infected male mosquito mates with an uninfected female mosquito, producing no viable offspring. This model describes the competitive dynamics between wAu-Wolbachia-infected and uninfected mosquitoes and the role of imperfect maternal transmission. By analysing the system via computing the basic reproduction number(s) and stability properties, the potential of the wAu strain as a viable strategy to control arboviral infections is established. The results of this work show that enhanced maintenance of Wolbachia infection at higher temperatures can overcome the lack of CI induction to support wAu-Wolbachia infected mosquito invasion. This study will support future arboviral control programs, that rely on the introduction of new Wolbachia variants.
Collapse
Affiliation(s)
- Samson T Ogunlade
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, QLD, Australia.
- College of Medicine and Dentistry, James Cook University, Townsville, QLD, Australia.
| | - Adeshina I Adekunle
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, QLD, Australia
| | - Michael T Meehan
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, QLD, Australia
| | - Diana P Rojas
- College of Public Health, Medical and Veterinary Sciences, Division of Tropical Health and Medicine, James Cook University, Townsville, QLD, Australia
| | - Emma S McBryde
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, QLD, Australia
| |
Collapse
|
7
|
The role of increased gonotrophic cycles in the establishment of Wolbachia in Anopheles populations. THEOR ECOL-NETH 2020. [DOI: 10.1007/s12080-020-00457-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
8
|
Modelling the Use of Vaccine and Wolbachia on Dengue Transmission Dynamics. Trop Med Infect Dis 2020; 5:tropicalmed5020078. [PMID: 32413992 PMCID: PMC7345660 DOI: 10.3390/tropicalmed5020078] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/30/2020] [Accepted: 05/06/2020] [Indexed: 01/09/2023] Open
Abstract
The use of vaccine and Wolbachia has been proposed as strategies against dengue. Research showed that the Wolbachia intervention is highly effective in areas with low to moderate transmission levels. On the other hand, the use of vaccine is strongly effective when it is implemented on seropositive individuals and areas with high transmission levels. The question that arises is could the combination of both strategies result in higher reduction in the number of dengue cases? This paper seeks to answer the aforementioned question by the use of a mathematical model. A deterministic model in the presence of vaccine and Wolbachia has been developed and analysed. Numerical simulations were presented and public health implications were discussed. The results showed that the performance of Wolbachia in reducing the number of dengue cases is better than that of vaccination if the vaccine efficacy is low, otherwise, the use of vaccine is sufficient to reduce dengue incidence and hence the combination of Wolbachia and vaccine is not necessary.
Collapse
|
9
|
Zhang H, Lui R. Releasing Wolbachia-infected Aedes aegypti to prevent the spread of dengue virus: A mathematical study. Infect Dis Model 2020; 5:142-160. [PMID: 31956742 PMCID: PMC6962337 DOI: 10.1016/j.idm.2019.12.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 12/10/2019] [Accepted: 12/10/2019] [Indexed: 01/11/2023] Open
Abstract
Wolbachia is a bacterium that is present in 60% of insects but it is not generally found in Aedes aegypti, the primary vector responsible for the transmission of dengue virus, Zika virus, and other human diseases caused by RNA viruses. Wolbachia has been shown to stop the growth of a variety of RNA viruses in Drosophila and in mosquitoes. Wolbachia-infected Ae. aegypti have both reproductive advantages and disadvantages over wild types. If Wolbachia-infected females are fertilized by either normal or infected males, the offspring are healthy and Wolbachia-positive. On the other hand, if Wolbachia-negative females are fertilized by Wolbachia-positive males, the offspring do not hatch. This phenomenon is called cytoplasmic incompatibility. Thus, Wolbachia-positive females have a reproductive advantage, and the Wolbachia is expanded in the population. On the other hand, Wolbachia-infected mosquitoes lay fewer eggs and generally have a shorter lifespan. In recent years, scientists have successfully released these Wolbachia-adapted mosquitoes into the wild in several countries and have achieved a high level of replacement with Wolbachia-positive mosquitoes. Here, we propose a minimal mathematical model to investigate the feasibility of such a release method. The model has five steady-states two of which are locally asymptotically stable. One of these stable steady-states has no Wolbachia-infected mosquitoes while for the other steady-state, all mosquitoes are infected with Wolbachia. We apply optimal control theory to find a release method that will drive the mosquito population close to the steady-state with only Wolbachia-infected mosquitoes in a two-year time period. Because some of the model parameters cannot be accurately measured or predicted, we also perform uncertainty and sensitivity analysis to quantify how variations in our model parameters affect our results.
Collapse
Affiliation(s)
- Hong Zhang
- Merck Research Laboratories, Rahway, NJ, 07065, USA
| | - Roger Lui
- Department of Mathematical Sciences, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
- Corresponding author.
| |
Collapse
|
10
|
Leftwich PT, Edgington MP, Harvey-Samuel T, Carabajal Paladino LZ, Norman VC, Alphey L. Recent advances in threshold-dependent gene drives for mosquitoes. Biochem Soc Trans 2018; 46:1203-1212. [PMID: 30190331 PMCID: PMC6195636 DOI: 10.1042/bst20180076] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 07/17/2018] [Accepted: 07/18/2018] [Indexed: 01/09/2023]
Abstract
Mosquito-borne diseases, such as malaria, dengue and chikungunya, cause morbidity and mortality around the world. Recent advances in gene drives have produced control methods that could theoretically modify all populations of a disease vector, from a single release, making whole species less able to transmit pathogens. This ability has caused both excitement, at the prospect of global eradication of mosquito-borne diseases, and concern around safeguards. Drive mechanisms that require individuals to be released at high frequency before genes will spread can therefore be desirable as they are potentially localised and reversible. These include underdominance-based strategies and use of the reproductive parasite Wolbachia Here, we review recent advances in practical applications and mathematical analyses of these threshold-dependent gene drives with a focus on implementation in Aedes aegypti, highlighting their mechanisms and the role of fitness costs on introduction frequencies. Drawing on the parallels between these systems offers useful insights into practical, controlled application of localised drives, and allows us to assess the requirements needed for gene drive reversal.
Collapse
Affiliation(s)
| | | | | | | | | | - Luke Alphey
- The Pirbright Institute, Pirbright, Woking, Surrey, U.K.
- Department of Zoology, University of Oxford, Oxford, U.K
| |
Collapse
|
11
|
Dorigatti I, McCormack C, Nedjati-Gilani G, Ferguson NM. Using Wolbachia for Dengue Control: Insights from Modelling. Trends Parasitol 2018; 34:102-113. [PMID: 29183717 PMCID: PMC5807169 DOI: 10.1016/j.pt.2017.11.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Revised: 11/01/2017] [Accepted: 11/02/2017] [Indexed: 12/23/2022]
Abstract
Dengue is the most common arboviral infection of humans, responsible for a substantial disease burden across the tropics. Traditional insecticide-based vector-control programmes have limited effectiveness, and the one licensed vaccine has a complex and imperfect efficacy profile. Strains of the bacterium Wolbachia, deliberately introduced into Aedes aegyptimosquitoes, have been shown to be able to spread to high frequencies in mosquito populations in release trials, and mosquitoes infected with these strains show markedly reduced vector competence. Thus, Wolbachia represents an exciting potential new form of biocontrol for arboviral diseases, including dengue. Here, we review how mathematical models give insight into the dynamics of the spread of Wolbachia, the potential impact of Wolbachia on dengue transmission, and we discuss the remaining challenges in evaluation and development.
Collapse
Affiliation(s)
- Ilaria Dorigatti
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London W2 1PG, UK; These authors made equal contributions
| | - Clare McCormack
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London W2 1PG, UK; These authors made equal contributions
| | - Gemma Nedjati-Gilani
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London W2 1PG, UK; These authors made equal contributions
| | - Neil M Ferguson
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London W2 1PG, UK.
| |
Collapse
|
12
|
Ndii MZ, Allingham D, Hickson RI, Glass K. The effect of Wolbachia on dengue outbreaks when dengue is repeatedly introduced. Theor Popul Biol 2016; 111:9-15. [PMID: 27217229 DOI: 10.1016/j.tpb.2016.05.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 05/09/2016] [Accepted: 05/11/2016] [Indexed: 02/01/2023]
Abstract
Use of the Wolbachia bacterium is a proposed new strategy to reduce dengue transmission, which results in around 390 million individuals infected annually. In places with strong variations in climatic conditions such as temperature and rainfall, dengue epidemics generally occur only at a certain time of the year. Where dengue is not endemic, the time of year in which imported cases enter the population plays a crucial role in determining the likelihood of outbreak occurrence. We use a mathematical model to study the effects of Wolbachia on dengue transmission dynamics and dengue seasonality. We focus in regions where dengue is not endemic but can spread due to the presence of a dengue vector and the arrival of people with dengue on a regular basis. Our results show that the time-window in which outbreaks can occur is reduced in the presence of Wolbachia-carrying Aedes aegypti mosquitoes by up to six weeks each year. We find that Wolbachia reduces overall case numbers by up to 80%. The strongest effect is obtained when the amplitude of the seasonal forcing is low (0.02-0.30). The benefits of Wolbachia also depend on the transmission rate, with the bacteria most effective at moderate transmission rates ranging between 0.08-0.12. Such rates are consistent with fitted estimates for Cairns, Australia.
Collapse
Affiliation(s)
- Meksianis Z Ndii
- School of Mathematical and Physical Sciences, The University of Newcastle, Australia; Department of Mathematics, Nusa Cendana University, Kupang-NTT, Indonesia.
| | - David Allingham
- School of Mathematical and Physical Sciences, The University of Newcastle, Australia.
| | - R I Hickson
- School of Mathematical and Physical Sciences, The University of Newcastle, Australia; IBM Research - Australia, Melbourne, Australia.
| | - Kathryn Glass
- National Centre for Epidemiology and Population Health, The Australian National University, Canberra, Australia.
| |
Collapse
|