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Zhang T, Zhao XQ. Threshold dynamics of an almost periodic vector-borne disease model. J Math Biol 2023; 87:72. [PMID: 37848568 DOI: 10.1007/s00285-023-02002-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/17/2023] [Accepted: 09/18/2023] [Indexed: 10/19/2023]
Abstract
Many infectious diseases cannot be transmitted from human to human directly, and the transmission needs to be done via a vector. It is well known that vectors' life cycles are highly dependent on their living environment. In order to investigate dynamics of vector-borne diseases under environment influence, we propose a vector-borne disease model with almost periodic coefficients. We derive the basic reproductive number [Formula: see text] for this model and establish a threshold type result on its global dynamics in terms of [Formula: see text]. As an illustrative example, we consider an almost periodic model of malaria transmission. Our numerical simulation results show that the basic reproductive number may be underestimated if almost periodic coefficients are replaced by their average values . Finally, we use our model to study the dengue fever transmission in Guangdong, China. The parameters are chosen to fit the reported data available for Guangdong. Numerical simulations indicate that the annual dengue fever case in Guangdong will increase steadily in the near future unless more effective control measures are implemented. Sensitivity analysis implies that the parameters with strong impact on the outcome are recovery rate, mosquito recruitment rate, mosquito mortality rate, baseline transmission rates between mosquito and human. This suggests that the effective control strategies may include intensive treatment, mosquito control, decreasing human contact number with mosquitoes (e.g., using bed nets and preventing mosquito bites), and environmental modification.
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Affiliation(s)
- Tailei Zhang
- School of Science, Chang'an University, Xi'an, Shaanxi, 710064, China.
| | - Xiao-Qiang Zhao
- Department of Mathematics and Statistics, Memorial University of Newfoundland, St. John's, NL, A1C 5S7, Canada
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2
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Guo Z, Liu W, Liu X, Abudunaibi B, Luo L, Wu S, Deng B, Yang T, Huang J, Wu S, Lei L, Zhao Z, Li Z, Li P, Liu C, Zhan M, Chen T. Model-based risk assessment of dengue fever transmission in Xiamen City, China. Front Public Health 2023; 11:1079877. [PMID: 36860401 PMCID: PMC9969104 DOI: 10.3389/fpubh.2023.1079877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 01/25/2023] [Indexed: 02/15/2023] Open
Abstract
Background Quantitative assessment of the risk of local transmission from imported dengue cases makes a great challenge to the development of public health in China. The purpose of this study is to observe the risk of mosquito-borne transmission in Xiamen City through ecological and insecticide resistance monitoring. Quantitative evaluation of mosquito insecticide resistance, community population and the number of imported cases affecting the transmission of dengue fever (DF) in Xiamen was carried out based on transmission dynamics model, so as to reveal the correlation between key risk factors and DF transmission. Methods Based on the dynamics model and combined with the epidemiological characteristics of DF in Xiamen City, a transmission dynamics model was built to simulate the secondary cases caused by imported cases to evaluate the transmission risk of DF, and to explore the influence of mosquito insecticide resistance, community population and imported cases on the epidemic situation of DF in Xiamen City. Results For the transmission model of DF, when the community population is between 10,000 and 25,000, changing the number of imported DF cases and the mortality rate of mosquitoes will have an impact on the spread of indigenous DF cases, however, changing the birth rate of mosquitoes did not gain more effect on the spread of local DF transmission. Conclusions Through the quantitative evaluation of the model, this study determined that the mosquito resistance index has an important influence on the local transmission of dengue fever caused by imported cases in Xiamen, and the Brayton index can also affect the local transmission of the disease.
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Affiliation(s)
- Zhinan Guo
- Xiamen Center for Disease Control and Prevention, Xiamen, Fujian, China
| | - Weikang Liu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, Fujian, China
| | - Xingchun Liu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, Fujian, China
| | - Buasiyamu Abudunaibi
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, Fujian, China
| | - Li Luo
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, Fujian, China
| | - Sihan Wu
- Xiamen Center for Disease Control and Prevention, Xiamen, Fujian, China
| | - Bin Deng
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, Fujian, China
| | - Tianlong Yang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, Fujian, China
| | - Jiefeng Huang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, Fujian, China
| | - Shenggen Wu
- Fujian Provincial Center for Disease Control and Prevention, Fuzhou, Fujian, China
| | - Lei Lei
- Xiamen Center for Disease Control and Prevention, Xiamen, Fujian, China
| | - Zeyu Zhao
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, Fujian, China
| | - Zhuoyang Li
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, Fujian, China
| | - Peihua Li
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, Fujian, China
| | - Chan Liu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, Fujian, China
| | - Meirong Zhan
- Fujian Provincial Center for Disease Control and Prevention, Fuzhou, Fujian, China
| | - Tianmu Chen
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, Fujian, China
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3
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Ogunlade ST, Meehan MT, Adekunle AI, McBryde ES. A Systematic Review of Mathematical Models of Dengue Transmission and Vector Control: 2010-2020. Viruses 2023; 15:254. [PMID: 36680294 PMCID: PMC9862433 DOI: 10.3390/v15010254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 01/12/2023] [Accepted: 01/13/2023] [Indexed: 01/19/2023] Open
Abstract
Vector control methods are considered effective in averting dengue transmission. However, several factors may modify their impact. Of these controls, chemical methods, in the long run, may increase mosquitoes' resistance to chemicides, thereby decreasing control efficacy. The biological methods, which may be self-sustaining and very effective, could be hampered by seasonality or heatwaves (resulting in, e.g., loss of Wolbachia infection). The environmental methods that could be more effective than the chemical methods are under-investigated. In this study, a systematic review is conducted to explore the present understanding of the effectiveness of vector control approaches via dengue transmission models.
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Affiliation(s)
- Samson T. Ogunlade
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville 4811, Australia
- College of Medicine and Dentistry, James Cook University, Townsville 4811, Australia
| | - Michael T. Meehan
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville 4811, Australia
| | - Adeshina I. Adekunle
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville 4811, Australia
- Defence Science and Technology Group, Department of Defence, Melbourne 3207, Australia
| | - Emma S. McBryde
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville 4811, Australia
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4
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Zheng B. Impact of releasing period and magnitude on mosquito population in a sterile release model with delay. J Math Biol 2022; 85:18. [PMID: 35917035 DOI: 10.1007/s00285-022-01785-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 07/01/2022] [Accepted: 07/17/2022] [Indexed: 10/16/2022]
Abstract
Assuming that there are multiple batches of sterile males reared and released during the maturation period, we derive a switching delay differential model to study the fate of wild females under an impulsive and periodic release of sterile males. For the release magnitude of each batch c, we find two threshold values [Formula: see text] and [Formula: see text], and prove that when [Formula: see text], the model admits exactly two periodic solutions, among which one is asymptotically stable and the other is unstable. The trivial equilibrium, corresponding to the elimination of wild females, is locally asymptotically stable, and it becomes globally asymptotically stable when [Formula: see text]. One key step is to prove that every solution is sandwiched between two "good" solutions.
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Affiliation(s)
- Bo Zheng
- Center for Applied Mathematics, Guangzhou University, Guangzhou, 510006, China. .,College of Mathematics and Information Sciences, Guangzhou University, Guangzhou, 510006, China.
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5
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Zhao S, Musa SS, Meng J, Qin J, He D. The long-term changing dynamics of dengue infectivity in Guangdong, China, from 2008-2018: a modelling analysis. Trans R Soc Trop Med Hyg 2021; 114:62-71. [PMID: 31638154 DOI: 10.1093/trstmh/trz084] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 07/02/2019] [Accepted: 07/19/2019] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Dengue remains a severe threat to public health in tropical and subtropical regions. In China, over 85% of domestic dengue cases are in the Guangdong province and there were 53 139 reported cases during 2008-2018. In Guangdong, the 2014 dengue outbreak was the largest in the last 20 y and it was probably triggered by a new strain imported from other regions. METHODS We studied the long-term patterns of dengue infectivity in Guangdong from 2008-2018 and compared the infectivity estimates across different periods. RESULTS We found that the annual epidemics approximately followed exponential growth during 2011-2014. The transmission rates were at a low level during 2008-2012, significantly increased 1.43-fold [1.22, 1.69] during 2013-2014 and then decreased back to a low level after 2015. By using the mosquito index and the likelihood-inference approach, we found that the new strain most likely invaded Guangdong in April 2014. CONCLUSIONS The long-term changing dynamics of dengue infectivity are associated with the new dengue virus strain invasion and public health control programmes. The increase in infectiousness indicates the potential for dengue to go from being imported to becoming an endemic in Guangdong, China.
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Affiliation(s)
- Shi Zhao
- School of Nursing, Hong Kong Polytechnic University, Hong Kong, China.,Department of Applied Mathematics, Hong Kong Polytechnic University, Hong Kong, China
| | - Salihu S Musa
- Department of Applied Mathematics, Hong Kong Polytechnic University, Hong Kong, China
| | - Jiayi Meng
- School of Economics and Finance, Xi'an International Studies University, Xi'an, China
| | - Jing Qin
- School of Nursing, Hong Kong Polytechnic University, Hong Kong, China
| | - Daihai He
- Department of Applied Mathematics, Hong Kong Polytechnic University, Hong Kong, China
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Thongsripong P, Qu Z, Yukich JO, Hyman JM, Wesson DM. An Investigation of Human-Mosquito Contact Using Surveys and Its Application in Assessing Dengue Viral Transmission Risk. JOURNAL OF MEDICAL ENTOMOLOGY 2020; 57:1942-1954. [PMID: 32652036 DOI: 10.1093/jme/tjaa134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Indexed: 06/11/2023]
Abstract
Aedes-borne viral diseases such as dengue fever are surging in incidence in recent years. To investigate viral transmission risks, the availability of local transmission parameters is essential. One of the most important factors directly determining infection risk is human-mosquito contact. Yet the contact rate is not often characterized, compared with other risk metrics such as vector density, because of the limited research tool options. In this study, human-mosquito contact was assessed in two study sites in the Southern United States using self-administered standardized survey instruments. The fraction of mosquito bites attributed to important vector species was estimated by human landing sampling. The survey participants reported a significantly higher outdoor mosquito bite exposure than indoor. The reported bite number was positively correlated with outdoor time during at-risk periods. There was also a significant effect of the study site on outdoor bite exposure, possibly due to the differing vector density. Thus, the levels of human-mosquito contact in this study were influenced both by the mosquito density and human behaviors. A dengue virus transmission model demonstrated that the observed difference in the contact rates results in differential virus transmission risks. Our findings highlight the practicality of using surveys to investigate human-mosquito contact in a setting where bite exposure levels differ substantially, and serve as a basis for further evaluations. This study underscores a new avenue that can be used in combination with other field methods to understand how changes in human behavior may influence mosquito bite exposure which drives mosquito-borne virus transmission.
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Affiliation(s)
| | - Zhuolin Qu
- Department of Mathematics, Tulane University, New Orleans, LA
| | - Joshua O Yukich
- Department of Tropical Medicine, Tulane University, New Orleans, LA
| | - James M Hyman
- Department of Mathematics, Tulane University, New Orleans, LA
| | - Dawn M Wesson
- Department of Tropical Medicine, Tulane University, New Orleans, LA
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Cai Y, Zhao S, Niu Y, Peng Z, Wang K, He D, Wang W. Modelling the effects of the contaminated environments on tuberculosis in Jiangsu, China. J Theor Biol 2020; 508:110453. [PMID: 32949588 PMCID: PMC7493753 DOI: 10.1016/j.jtbi.2020.110453] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 08/11/2020] [Accepted: 08/13/2020] [Indexed: 02/06/2023]
Abstract
A tuberculosis model incorporating contaminated environments is developed. A threshold theorem of the model is established. The annual average of the basic reproduction number is obtained. TB in Jiangsu is an endemic disease and will persist for a long time.
Tuberculosis (TB) is still an important public health issue in Jiangsu province, China. In this study, based on the TB transmission routes and the statistical data of TB cases, we formulate a novel TB epidemic model accounting for the effects of the contaminated environments on TB transmission dynamics. The value of this study lies in two aspects. Mathematically, we define the basic reproduction number, R0, and prove that R0 can be used to govern the threshold dynamics of the model. Epidemiologically, we find that the annual average R0 is 1.13,>1 and TB in Jiangsu is an endemic disease. Therefore, in order to control the TB in Jiangsu efficiently, we must decrease the virus shedding rate or increase the recovery rates, and increase the environmental clearance rate.
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Affiliation(s)
- Yongli Cai
- School of Mathematics and Statistics, Huaiyin Normal University, Huaian 223300 PR China.
| | - Shi Zhao
- Division of Biostatistics, JC School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong 999077 PR China; Clinical Trials and Biostatistics Lab, Shenzhen Research Institute, Chinese University of Hong Kong, Shenzhen 518057 PR China
| | - Yun Niu
- School of Urban and Environmental Science, Huaiyin Normal University, Huaian 223300 PR China
| | - Zhihang Peng
- School of Public Health, Nanjing Medical University, Nanjing 211166 PR China.
| | - Kai Wang
- Department of Medical Engineering and Technology, Xinjiang Medical University, Urumqi 830011 PR China.
| | - Daihai He
- Department of Applied Mathematics, Hong Kong Polytechnic University, Hong Kong 999077 PR China.
| | - Weiming Wang
- School of Mathematics and Statistics, Huaiyin Normal University, Huaian 223300 PR China.
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8
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Liu Y, Lillepold K, Semenza JC, Tozan Y, Quam MBM, Rocklöv J. Reviewing estimates of the basic reproduction number for dengue, Zika and chikungunya across global climate zones. ENVIRONMENTAL RESEARCH 2020; 182:109114. [PMID: 31927301 DOI: 10.1016/j.envres.2020.109114] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 01/01/2020] [Accepted: 01/02/2020] [Indexed: 05/14/2023]
Abstract
BACKGROUND Globally, dengue, Zika virus, and chikungunya are important viral mosquito-borne diseases that infect millions of people annually. Their geographic range includes not only tropical areas but also sub-tropical and temperate zones such as Japan and Italy. The relative severity of these arboviral disease outbreaks can vary depending on the setting. In this study we explore variation in the epidemiologic potential of outbreaks amongst these climatic zones and arboviruses in order to elucidate potential reasons behind such differences. METHODOLOGY We reviewed the peer-reviewed literature (PubMed) to obtain basic reproduction number (R0) estimates for dengue, Zika virus, and chikungunya from tropical, sub-tropical and temperate regions. We also computed R0 estimates for temperate and sub-tropical climate zones, based on the outbreak curves in the initial outbreak phase. Lastly we compared these estimates across climate zones, defined by latitude. RESULTS Of 2115 studies, we reviewed the full text of 128 studies and included 65 studies in our analysis. Our results suggest that the R0 of an arboviral outbreak depends on climate zone, with lower R0 estimates, on average, in temperate zones (R0 = 2.03) compared to tropical (R0 = 3.44) and sub-tropical zones (R0 = 10.29). The variation in R0 was considerable, ranging from 0.16 to 65. The largest R0 was for dengue (65) and was estimated by the Ross-Macdonald model in the tropical zone, whereas the smallest R0 (0.16) was for Zika virus and was estimated statistically from an outbreak curve in the sub-tropical zone. CONCLUSIONS The results indicate climate zone to be an important determinant of the basic reproduction number, R0, for dengue, Zika virus, and chikungunya. The role of other factors as determinants of R0, such as methods, environmental and social conditions, and disease control, should be further investigated. The results suggest that R0 may increase in temperate regions in response to global warming, and highlight the increasing need for strengthening preparedness and control activities.
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Affiliation(s)
- Ying Liu
- School of International Business, Xiamen University Tan Kah Kee College, Zhangzhou, 363105, China.
| | - Kate Lillepold
- European Centre for Disease Prevention and Control, Stockholm, Sweden
| | - Jan C Semenza
- European Centre for Disease Prevention and Control, Stockholm, Sweden
| | - Yesim Tozan
- New York University, College of Global Public Health, New York, NY, USA.
| | - Mikkel B M Quam
- Department of Public Health and Clinical Medicine, Section of Sustainable Health, Umeå University, Umeå, Sweden
| | - Joacim Rocklöv
- Department of Public Health and Clinical Medicine, Section of Sustainable Health, Umeå University, Umeå, Sweden.
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Zhao S, Musa SS, Hebert JT, Cao P, Ran J, Meng J, He D, Qin J. Modelling the effective reproduction number of vector-borne diseases: the yellow fever outbreak in Luanda, Angola 2015-2016 as an example. PeerJ 2020; 8:e8601. [PMID: 32149023 PMCID: PMC7049463 DOI: 10.7717/peerj.8601] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 01/19/2020] [Indexed: 01/02/2023] Open
Abstract
The burden of vector-borne diseases (Dengue, Zika virus, yellow fever, etc.) gradually increased in the past decade across the globe. Mathematical modelling on infectious diseases helps to study the transmission dynamics of the pathogens. Theoretically, the diseases can be controlled and eventually eradicated by maintaining the effective reproduction number, (R eff ), strictly less than 1. We established a vector-host compartmental model, and derived (R eff ) for vector-borne diseases. The analytic form of the (R eff ) was found to be the product of the basic reproduction number and the geometric average of the susceptibilities of the host and vector populations. The (R eff ) formula was demonstrated to be consistent with the estimates of the 2015-2016 yellow fever outbreak in Luanda, and distinguished the second minor epidemic wave. For those using the compartmental model to study the vector-borne infectious disease epidemics, we further remark that it is important to be aware of whether one or two generations is considered for the transition "from host to vector to host" in reproduction number calculation.
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Affiliation(s)
- Shi Zhao
- School of Nursing, Hong Kong Polytechnic University, Hong Kong, China
- Division of Biostatistics, JC School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong, China
- Clinical Trials and Biostatistics Lab, Shenzhen Research Institute, Chinese University of Hong Kong, Shenzhen, China
| | - Salihu S. Musa
- Department of Applied Mathematics, Hong Kong Polytechnic University, Hong Kong, China
| | - Jay T. Hebert
- Department of Applied Mathematics, Hong Kong Polytechnic University, Hong Kong, China
| | - Peihua Cao
- Department of Hepatobiliary Surgery II, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Jinjun Ran
- School of Public Health, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
| | - Jiayi Meng
- School of Economics and Finance, Xi’an International Studies University, Xi’an, China
| | - Daihai He
- Department of Applied Mathematics, Hong Kong Polytechnic University, Hong Kong, China
| | - Jing Qin
- School of Nursing, Hong Kong Polytechnic University, Hong Kong, China
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Ullah S, Khan MF, Shah SAA, Farooq M, Khan MA, Mamat MB. Optimal control analysis of vector-host model with saturated treatment. EUROPEAN PHYSICAL JOURNAL PLUS 2020; 135:839. [PMID: 33101826 PMCID: PMC7567007 DOI: 10.1140/epjp/s13360-020-00855-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 10/09/2020] [Indexed: 05/22/2023]
Abstract
Vector-host infectious diseases remain a challenging issue and cause millions of deaths each year globally. In such outbreaks, many countries especially developing or underdevelopment faces a situation where the number of infected individuals is getting larger and the medical facilities are limited. In this paper, we construct an epidemic model to explore the transmission dynamics of vector-borne diseases with nonlinear saturated incidence rate and saturated treatment function. This type of incidence rate, as well as the saturated treatment function, is also known as the Holling type II form and describes the effect of delayed treatment. Initially, we formulate a mathematical model and then present the basic analysis of the model including the positivity and boundedness of the solution. The threshold quantity R 0 is presented and the stability analysis of the system is carried out for the model equilibria. The global stability results are shown using the Lyapunov function of Goh-Voltera type. The existence of backward bifurcation is discussed using the central manifold theory. Further, the global sensitivity analysis of the model is carried out using the Latin Hypercube sampling and the partial rank correlation coefficient techniques. Moreover, an optimal control problem is formulated and the necessary optimality conditions are investigated in order to eradicate the disease in a community. Four strategies are presented by choosing different set of controls combination for the disease minimization. Finally, the numerical simulations of each strategy are depicted to demonstrate the importance of suggesting control interventions on the disease dynamics and eradication.
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Affiliation(s)
- Saif Ullah
- Department of Mathematics, University of Peshawar, Peshawar, Khyber Pakhtunkhwa 25000 Pakistan
| | - Muhammad Farooq Khan
- Faculty of Informatics and Computing, Universiti Sultan Zainul Abidin, Gang Badak Campus, Kuala Terengganu, Malaysia
| | - Syed Azhar Ali Shah
- Department of Mathematics, University of Swabi, Khyber Pakhtunkhwa, Pakistan
| | - Muhammad Farooq
- Department of Mathematics, University of Peshawar, Peshawar, Khyber Pakhtunkhwa 25000 Pakistan
| | - Muhammad Altaf Khan
- Informetrics Research Group, Ton Duc Thang University, Ho Chi Minh City, Vietnam
- Faculty of Mathematics and Statistics, Ton Duc Thang University, Ho Chi Minh City, Vietnam
| | - Mustafa bin Mamat
- Faculty of Informatics and Computing, Universiti Sultan Zainul Abidin, Gang Badak Campus, Kuala Terengganu, Malaysia
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Ullah S, Khan MF, Shah SAA, Farooq M, Khan MA, Mamat MB. Optimal control analysis of vector-host model with saturated treatment. EUROPEAN PHYSICAL JOURNAL PLUS 2020. [PMID: 33101826 DOI: 10.1140/epjp/s13360-020-00615-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Vector-host infectious diseases remain a challenging issue and cause millions of deaths each year globally. In such outbreaks, many countries especially developing or underdevelopment faces a situation where the number of infected individuals is getting larger and the medical facilities are limited. In this paper, we construct an epidemic model to explore the transmission dynamics of vector-borne diseases with nonlinear saturated incidence rate and saturated treatment function. This type of incidence rate, as well as the saturated treatment function, is also known as the Holling type II form and describes the effect of delayed treatment. Initially, we formulate a mathematical model and then present the basic analysis of the model including the positivity and boundedness of the solution. The threshold quantity R 0 is presented and the stability analysis of the system is carried out for the model equilibria. The global stability results are shown using the Lyapunov function of Goh-Voltera type. The existence of backward bifurcation is discussed using the central manifold theory. Further, the global sensitivity analysis of the model is carried out using the Latin Hypercube sampling and the partial rank correlation coefficient techniques. Moreover, an optimal control problem is formulated and the necessary optimality conditions are investigated in order to eradicate the disease in a community. Four strategies are presented by choosing different set of controls combination for the disease minimization. Finally, the numerical simulations of each strategy are depicted to demonstrate the importance of suggesting control interventions on the disease dynamics and eradication.
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Affiliation(s)
- Saif Ullah
- Department of Mathematics, University of Peshawar, Peshawar, Khyber Pakhtunkhwa 25000 Pakistan
| | - Muhammad Farooq Khan
- Faculty of Informatics and Computing, Universiti Sultan Zainul Abidin, Gang Badak Campus, Kuala Terengganu, Malaysia
| | - Syed Azhar Ali Shah
- Department of Mathematics, University of Swabi, Khyber Pakhtunkhwa, Pakistan
| | - Muhammad Farooq
- Department of Mathematics, University of Peshawar, Peshawar, Khyber Pakhtunkhwa 25000 Pakistan
| | - Muhammad Altaf Khan
- Informetrics Research Group, Ton Duc Thang University, Ho Chi Minh City, Vietnam
- Faculty of Mathematics and Statistics, Ton Duc Thang University, Ho Chi Minh City, Vietnam
| | - Mustafa Bin Mamat
- Faculty of Informatics and Computing, Universiti Sultan Zainul Abidin, Gang Badak Campus, Kuala Terengganu, Malaysia
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Prediction model for dengue fever based on interactive effects between multiple meteorological factors in Guangdong, China (2008-2016). PLoS One 2019; 14:e0225811. [PMID: 31815950 PMCID: PMC6901221 DOI: 10.1371/journal.pone.0225811] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 11/13/2019] [Indexed: 02/03/2023] Open
Abstract
Introduction In order to improve the prediction accuracy of dengue fever incidence, we constructed a prediction model with interactive effects between meteorological factors, based on weekly dengue fever cases in Guangdong, China from 2008 to 2016. Methods Dengue fever data were derived from statistical data from the China National Notifiable Infectious Disease Reporting Information System. Daily meteorological data were obtained from the China Integrated Meteorological Information Sharing System. The minimum temperature for transmission was identified using data fitting and the Ross-Macdonald model. Correlations and interactive effects were examined using Spearman’s rank correlation and multivariate analysis of variance. A probit regression model to describe the incidence of dengue fever from 2008 to 2016 and forecast the 2017 incidence was constructed, based on key meteorological factors, interactive effects, mosquito-vector factors, and other important factors. Results We found the minimum temperature suitable for dengue transmission was ≥18°C, and as 97.91% of cases occurred when the minimum temperature was above 18 °C, the data were used for model training and construction. Epidemics of dengue are related to mean temperature, maximum/minimum and mean atmospheric pressure, and mean relative humidity. Moreover, interactions occur between mean temperature, minimum atmospheric pressure, and mean relative humidity. Our weekly probit regression prediction model is 0.72. Prediction of dengue cases for the first 41 weeks of 2017 exhibited goodness of fit of 0.60. Conclusion Our model was accurate and timely, with consideration of interactive effects between meteorological factors.
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Chen Y, Gao J, Yang L, Li C, Chen R, Xie Z, Ren R. A predominant dengue virus-1 endemic strain and the vector competence of Aedes albopictus from Guangzhou City, China. Acta Trop 2019; 199:104975. [PMID: 30943381 DOI: 10.1016/j.actatropica.2019.03.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 03/13/2019] [Accepted: 03/29/2019] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Dengue has been a serious public health burden and dengue virus-1 (DENV-1) is the predominant strain in Guangdong province, China. Differences exist in the transmission dynamics amongAedes albopictus and DENV in different geographical regions. However, little is known about the vector competence of indigenous Aedes albopictus for the predominant dengue strain in Guangdong province, China. METHODOLOGY In this study, the field-derivedAedes albopictus collected from Guangzhou city, Guangdong province were infected with the predominant DENV endemic strain DENV-1 GZ201401 by feeding on serially diluted artificial infectious blood or infected suckling mice. DENV-infected mosquitoes were evaluated for viral load at five-time intervals in three tissues, the head, body and legs using reverse transcription-quantitative PCR (RT-qPCR). The vertical transmission of DENV in Ades albopictus was also analysed. Suckling mice were used to assess the transmission of DENV by Aedes albopictus. RESULTS There was no difference in infection rates between mosquitoes infected by infected suckling mice or by artificial infectious blood. The proportion of DENV-1 positive mosquitoes increased over time after an infectious blood meal, but there was no difference in the positive rate beyond 7days after the blood meal. The positive rate of DENV-1 infected mosquitoes increased with the DENV titer in the blood meal. Most of the infections the infected mosquitoes were disseminated more than 7 days after imbibing the artificial infectious blood. The median infective doses (MID50) at 7,14,21 and 28 days after artificial infectious blood meal [7, 14, 21 and 28 days post-infection (dpi)] were 7.86 × 107, 1.57 × 107, 6.39 × 106 and 4.96 × 106 TCID50 (50% tissue culture infective dose)/ml, respectively. The mosquitoes can spread DENV-1 GZ201401 to hosts as early as 3 dpi. The vertical transmission of DENV-1 was documented with a cumulative rate of 17.61%. CONCLUSION Our results demonstrated that Aedes albopictus mosquitoes are competent vectors for DENV-1, and are capable of maintaining autochthonous dengue outbreaks in Guangdong province, China, which may have been promoted by vertical transmission.
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Yi B, Chen Y, Ma X, Rui J, Cui JA, Wang H, Li J, Chan SF, Wang R, Ding K, Xie L, Zhang D, Jiao S, Lao X, Chiang YC, Su Y, Zhao B, Xu G, Chen T. Incidence dynamics and investigation of key interventions in a dengue outbreak in Ningbo City, China. PLoS Negl Trop Dis 2019; 13:e0007659. [PMID: 31415559 PMCID: PMC6711548 DOI: 10.1371/journal.pntd.0007659] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 08/27/2019] [Accepted: 07/24/2019] [Indexed: 11/19/2022] Open
Abstract
Background The reported incidence of dengue fever increased dramatically in recent years in China. This study aimed to investigate and to assess the effectiveness of intervention implemented in a dengue outbreak in Ningbo City, Zhejiang Province, China. Methods Data of a dengue outbreak were collected in Ningbo City in China by a field epidemiological survey according to a strict protocol and case definition. Serum specimens of all cases were collected for diagnosis and the virological characteristics were detected by using polymerase chain reaction (PCR) and gene sequencing. Vector surveillance was implemented during the outbreak to collect the larva and adult mosquito densities to calculate the Breteau Index (BI) and human biting rate (HBR), respectively. Data of monthly BI and light-trap density in 2018 were built to calculate the seasonality of the vector. A transmission mathematical model was developed to dynamic the incidence of the disease. The parameters of the model were estimated by the data of the outbreak and vector surveillance data in 2018. The effectiveness of the interventions implemented during the outbreak was assessed by the data and the modelling. Results From 11 August to 8 September, 2018, a dengue outbreak was reported with 27 confirmed cases in a population of 5536-people community (community A) of Ningbo City. Whole E gene sequences were obtained from 24 cases and were confirmed as dengue virus type 1 (DENV-1). The transmission source of the outbreak was origin from community B where a dengue case having the same E gene sequence was onset on 30 July. Aedes albopictus was the only vector species in the area. The value of BI and HBR was 57.5 and 12 per person per hour respectively on 18 August, 2018 and decreased dramatically after interventions. The transmission model fitted well (χ2 = 6.324, P = 0.388) with the reported cases data. With no intervention, the total simulated number of the cases would be 1728 with a total attack rate (TAR) of 31.21% (95%CI: 29.99%– 32.43%). Case isolation and larva control (LC) have almost the same TAR and duration of outbreak (DO) as no intervention. Different levels of reducing HBR (rHBR) had different effectiveness with TARs ranging from 1.05% to 31.21% and DOs ranging from 27 days to 102 days. Adult vector control (AVC) had a very low TAR and DO. “LC+AVC” had a similar TAR and DO as that of AVC. “rHBR100%+LC”, “rHBR100%+AVC”, “rHBR100%+LC+AVC” and “rHBR100%+LC+AVC+Iso” had the same effectiveness. Conclusions Without intervention, DENV-1 could be transmitted rapidly within a short period of time and leads to high attack rate in community in China. AVC or rHBR should be recommended as primary interventions to control rapid transmission of the dengue virus at the early stage of an outbreak. Dengue has led to heavy disease burden in China. The reported incidence of the disease increased dramatically in recent years and cases have expanded from southern to central and northern part of China. In this study, the findings include that DENV-1 can transmit rapidly with a short period of time and leads to high attack rate in community, and that rHBR or AVC should be recommended as primary interventions to control rapid transmission of dengue virus at the early stage of an outbreak. Therefore, dengue outbreak is at high risk in many areas in China because of the potential high receptivity (widely distribution of Ae. albopictus) and vulnerability (high frequency of the importation) of the transmission. The high transmissibility of the virus makes it hard and urgent to control the outbreak. Delayed intervention (larvae control or case isolation) is hard to show its effectiveness and the interventions without delay are strongly recommended. Bed net or mosquito repellents were encouraged to use in the community to reduce HBR, and space spraying of insecticides were recommended to control adult vector during the outbreak.
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Affiliation(s)
- Bo Yi
- Ningbo Municipal Center for Disease Control and Prevention, Ningbo City, Zhejiang Province, People’s Republic of China
| | - Yi Chen
- Ningbo Municipal Center for Disease Control and Prevention, Ningbo City, Zhejiang Province, People’s Republic of China
| | - Xiao Ma
- Ningbo Municipal Center for Disease Control and Prevention, Ningbo City, Zhejiang Province, People’s Republic of China
| | - Jia Rui
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen City, Fujian Province, People’s Republic of China
| | - Jing-An Cui
- School of Science, Beijing University of Civil Engineering and Architecture, Beijing, People's Republic of China
| | - Haibin Wang
- Haishu District Center for Disease Control and Prevention, Ningbo City, Zhejiang Province, People’s Republic of China
| | - Jia Li
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen City, Fujian Province, People’s Republic of China
| | - Soi-Fan Chan
- Center for Disease Control and Prevention, Health Bureau, Macao SAR, People’s Republic of China
| | - Rong Wang
- Ningbo Municipal Center for Disease Control and Prevention, Ningbo City, Zhejiang Province, People’s Republic of China
| | - Keqin Ding
- Ningbo Municipal Center for Disease Control and Prevention, Ningbo City, Zhejiang Province, People’s Republic of China
| | - Lei Xie
- Ningbo Municipal Center for Disease Control and Prevention, Ningbo City, Zhejiang Province, People’s Republic of China
| | - Dongliang Zhang
- Ningbo Municipal Center for Disease Control and Prevention, Ningbo City, Zhejiang Province, People’s Republic of China
| | - Shuli Jiao
- Ningbo Municipal Center for Disease Control and Prevention, Ningbo City, Zhejiang Province, People’s Republic of China
| | - Xuying Lao
- Ningbo Municipal Center for Disease Control and Prevention, Ningbo City, Zhejiang Province, People’s Republic of China
| | - Yi-Chen Chiang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen City, Fujian Province, People’s Republic of China
| | - Yanhua Su
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen City, Fujian Province, People’s Republic of China
| | - Benhua Zhao
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen City, Fujian Province, People’s Republic of China
| | - Guozhang Xu
- Ningbo Municipal Center for Disease Control and Prevention, Ningbo City, Zhejiang Province, People’s Republic of China
| | - Tianmu Chen
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen City, Fujian Province, People’s Republic of China
- * E-mail:
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Wu H, Wu C, Lu Q, Ding Z, Xue M, Lin J. Evaluating the effects of control interventions and estimating the inapparent infections for dengue outbreak in Hangzhou, China. PLoS One 2019; 14:e0220391. [PMID: 31393899 PMCID: PMC6687121 DOI: 10.1371/journal.pone.0220391] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 07/15/2019] [Indexed: 11/19/2022] Open
Abstract
Background The number of dengue fever (DF) cases and the number of dengue outbreaks have increased in recent years in Zhejiang Province, China. An unexpected dengue outbreak was reported in Hangzhou in 2017 and caused more than one thousand dengue cases. This study was undertaken to evaluate the effectiveness of the actual control measures, estimate the proportion of inapparent infections during this outbreak and simulate epidemic development based on different levels of control measures taking inapparent infections into consideration. Methods The epidemic data of dengue cases in Hangzhou, Zhejiang Province, in 2017 and the number of the people exposed to the outbreaks were obtained from the China Information Network System of Disease Prevention and Control. The epidemic without intervention measures was used to estimate the unknown parameters. A susceptible-exposed-infectious/inapparent-recovered (SEIAR) model was used to estimate the effectiveness of the control interventions. The inapparent infections were also evaluated at the same time. Results In total, 1137 indigenous dengue cases were reported in Hangzhou in 2017. The number of indigenous dengue cases was estimated by the SEIAR model. This number was predicted to reach 6090 by the end of November 2, 2017, if no control measures were implemented. The total number of reported cases was reduced by 81.33% in contrast to the estimated incidence without intervention. The number of average daily inapparent cases was 10.18 times higher than the number of symptomatic cases. The earlier and more rigorously the vector control interventions were implemented, the more effective they were. The results showed that implementing vector control continuously for more than twenty days was more effective than every few days of implementation. Case isolation is not sufficient enough for epidemic control and only reduced the incidence by 38.10% in contrast to the estimated incidence without intervention, even if case isolation began seven days after the onset of the first case. Conclusions The practical control interventions in the outbreaks that occurred in Hangzhou City were highly effective. The proportion of inapparent infections was large, and it played an important role in transmitting the disease during this epidemic. Early, continuous and high efficacy vector control interventions are necessary to limit the development of a dengue epidemic. Timely diagnosis and case reporting are important in the intervention at an early stage of the epidemic.
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Affiliation(s)
- Haocheng Wu
- Zhejiang Province Center for Disease Control and Prevention, Hangzhou, Zhejiang Province, China
- Key Laboratory for Vaccine, Prevention and Control of Infectious Disease of Zhejiang Province, Hangzhou, Zhejiang Province, China
| | - Chen Wu
- Zhejiang Province Center for Disease Control and Prevention, Hangzhou, Zhejiang Province, China
| | - Qinbao Lu
- Zhejiang Province Center for Disease Control and Prevention, Hangzhou, Zhejiang Province, China
| | - Zheyuan Ding
- Zhejiang Province Center for Disease Control and Prevention, Hangzhou, Zhejiang Province, China
| | - Ming Xue
- Hangzhou Centre for Disease Control and Prevention, Hangzhou, Zhejiang, Province, China
| | - Junfen Lin
- Zhejiang Province Center for Disease Control and Prevention, Hangzhou, Zhejiang Province, China
- Key Laboratory for Vaccine, Prevention and Control of Infectious Disease of Zhejiang Province, Hangzhou, Zhejiang Province, China
- * E-mail:
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Zheng B, Liu X, Tang M, Xi Z, Yu J. Use of age-stage structural models to seek optimal Wolbachia-infected male mosquito releases for mosquito-borne disease control. J Theor Biol 2019; 472:95-109. [PMID: 30991073 DOI: 10.1016/j.jtbi.2019.04.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 04/08/2019] [Accepted: 04/10/2019] [Indexed: 12/31/2022]
Abstract
Due to the lack of vaccines and effective clinical cures, current methods to control mosquito-borne viral diseases such as dengue and Zika are primarily targeting to eradicate the major mosquito vectors. However, traditional means, including larval source reduction and applications of insecticides etc, are not sufficient to keep vector population density below the epidemic risk threshold. An innovative and operational strategy is to release Wolbachia-infected male mosquitoes into wild areas to sterilize wild female mosquitoes by cytoplasmic incompatibility. To help design optimal release strategies before large scale and expensive operations, we started with an age-stage discrete model to track daily abundances of wild female mosquitoes, which fitted the field data collected by Guangzhou Center for Disease Control and Prevention from 2015 to 2017 with an average Pearson correlation coefficient 0.7283. Then, we modeled the Wolbachia interference by introducing the proportional releases of Wolbachia-infected males, and eight optimal release policies which guarantee more than 95% suppression efficiency were sought. Finally, we assessed the robustness of the optimality of the eight release policies by allowing the migration of females or the contamination of Wolbachia-infected females by two further extended mathematical models.
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Affiliation(s)
- Bo Zheng
- College of Mathematics and Information Sciences, Guangzhou University, Guangzhou 510006, PR China; Center for Applied Mathematics, Guangzhou University, Guangzhou 510006, China
| | - Xiaoping Liu
- College of Mathematics and Information Sciences, Guangzhou University, Guangzhou 510006, PR China; Center for Applied Mathematics, Guangzhou University, Guangzhou 510006, China
| | - Moxun Tang
- Department of Mathematics, Michigan State University, East Lansing, MI 48824, USA
| | - Zhiyong Xi
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Jianshe Yu
- College of Mathematics and Information Sciences, Guangzhou University, Guangzhou 510006, PR China; Center for Applied Mathematics, Guangzhou University, Guangzhou 510006, China.
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Zhu G, Liu T, Xiao J, Zhang B, Song T, Zhang Y, Lin L, Peng Z, Deng A, Ma W, Hao Y. Effects of human mobility, temperature and mosquito control on the spatiotemporal transmission of dengue. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 651:969-978. [PMID: 30360290 DOI: 10.1016/j.scitotenv.2018.09.182] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 09/14/2018] [Accepted: 09/14/2018] [Indexed: 05/06/2023]
Abstract
Dengue transmission exhibits evident geographic variations and seasonal differences. Such heterogeneity is caused by various impact factors, in which temperature and host/vector behaviors could drive its spatiotemporal transmission, but mosquito control could stop its progression. These factors together contribute to the observed distributions of dengue incidence from surveillance systems. To effectively and efficiently monitor and response to dengue outbreak, it would be necessary to systematically model these factors and their impacts on dengue transmission. This paper introduces a new modeling framework with consideration of multi-scale factors and surveillance data to clarify the hidden dynamics accounting for dengue spatiotemporal transmission. The model is based on compartmental system which takes into account the biting-based interactions among humans, viruses and mosquitoes, as well as the essential impacts of human mobility, temperature and mosquito control. This framework was validated with real epidemic data by applying retrospectively to the 2014 dengue epidemic in the Pearl River Delta (PRD) in southern China. The results indicated that suitable condition of temperature could be responsible for the explosive dengue outbreak in the PRD, and human mobility could be the causal factor leading to its spatial transmission across different cities. It was further found that mosquito intervention has significantly reduced dengue incidence, where a total of 52,770 (95% confidence interval [CI]: 29,231-76,308) dengue cases were prevented in the PRD in 2014. The findings can offer new insights for improving the predictability and risk assessment of dengue epidemics. The model also can be readily extended to investigate the transmission dynamics of other mosquito-borne diseases.
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Affiliation(s)
- Guanghu Zhu
- Department of Medical Statistics and Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China; Department of Mathematics and Computing Science, Guilin University of Electronic Technology, Guilin 541004, China; Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China
| | - Tao Liu
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China
| | - Jianpeng Xiao
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China
| | - Bing Zhang
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China
| | - Tie Song
- Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, China
| | - Yonghui Zhang
- Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, China
| | - Lifeng Lin
- Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, China
| | - Zhiqiang Peng
- Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, China
| | - Aiping Deng
- Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, China
| | - Wenjun Ma
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China.
| | - Yuantao Hao
- Department of Medical Statistics and Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China.
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Zheng B, Yu J. Characterization of Wolbachia enhancing domain in mosquitoes with imperfect maternal transmission. JOURNAL OF BIOLOGICAL DYNAMICS 2018; 12:596-610. [PMID: 30025503 DOI: 10.1080/17513758.2018.1499969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 07/03/2018] [Indexed: 06/08/2023]
Abstract
A novel method to reduce the burden of dengue is to seed wild mosquitoes with Wolbachia-infected mosquitoes in dengue-endemic areas. Concerns in current mathematical models are to locate the Wolbachia introduction threshold. Our recent findings manifest that the threshold is highly dependent on the initial population size once Wolbachia infection alters the logistic control death rate of infected females. However, counting mosquitoes is beyond the realms of possibility. A plausible method is to monitor the infection frequency. We propose the concept of Wolbachia enhancing domain in which the infection frequency keeps increasing. A detailed description of the domain is presented. Our results suggest that both the initial population size and the infection frequency should be taken into account for optimal release strategies. Both Wolbachia fixation and extinction permit the oscillation of the infection frequency.
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Affiliation(s)
- Bo Zheng
- a College of Mathematics and Information Sciences , Guangzhou University , Guangzhou , People's Republic of China
- b Center for Applied Mathematics , Guangzhou University , Guangzhou , People's Republic of China
| | - Jianshe Yu
- a College of Mathematics and Information Sciences , Guangzhou University , Guangzhou , People's Republic of China
- b Center for Applied Mathematics , Guangzhou University , Guangzhou , People's Republic of China
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Zou L, Chen J, Feng X, Ruan S. Analysis of a Dengue Model with Vertical Transmission and Application to the 2014 Dengue Outbreak in Guangdong Province, China. Bull Math Biol 2018; 80:2633-2651. [PMID: 30083966 DOI: 10.1007/s11538-018-0480-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 07/23/2018] [Indexed: 11/25/2022]
Abstract
There is evidence showing that vertical transmission of dengue virus exists in Aedes mosquitoes. In this paper, we propose a deterministic dengue model with vertical transmission in mosquitoes by including aquatic mosquitoes (eggs, larvae and pupae), adult mosquitoes (susceptible, exposed and infectious) and human hosts (susceptible, exposed, infectious and recovered). We first analyze the existence and stability of disease-free equilibria, calculate the basic reproduction number and discuss the existence of the disease-endemic equilibrium. Then, we study the impact of vertical transmission of the virus in mosquitoes on the spread dynamics of dengue. We also use the model to simulate the reported infected human data from the 2014 dengue outbreak in Guangdong Province, China, carry out sensitivity analysis of the basic reproduction number in terms of the model parameters, and seek for effective control measures for the transmission of dengue virus.
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Affiliation(s)
- Lan Zou
- Department of Mathematics, Sichuan University, Chengdu, 610064, Sichuan, China
| | - Jing Chen
- Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, 3301 College Ave., Fort Lauderdale, FL, 33314, USA
| | - Xiaomei Feng
- Department of Mathematics, Yuncheng University, Yuncheng, 044000, Shanxi, China
| | - Shigui Ruan
- Department of Mathematics, University of Miami, Coral Gables, FL, 33146, USA.
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Zhu G, Xiao J, Zhang B, Liu T, Lin H, Li X, Song T, Zhang Y, Ma W, Hao Y. The spatiotemporal transmission of dengue and its driving mechanism: A case study on the 2014 dengue outbreak in Guangdong, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 622-623:252-259. [PMID: 29216466 DOI: 10.1016/j.scitotenv.2017.11.314] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 11/15/2017] [Accepted: 11/27/2017] [Indexed: 05/19/2023]
Abstract
Dengue transmission is a complex spatiotemporal process with hidden interactions between hosts, vectors, and viruses as well as environment. This study aims to identify the transmission patterns and the driving mechanism that contributed to the dengue epidemics occurred in Guangdong Province of China in 2014. Based on the city-specific epidemiological, meteorological, demographic and geographic data, we first performed wavelet analysis and then integrated the key dynamics (i.e., mosquito population dynamics, human movement, virus transmission, and parameter estimation) into a transmission model. Using these methods, we found a clear temporal sequence and correlation of dengue transmission between cities, and such relationship is associated with socioeconomic factors. We further obtained the specific component of dengue incidence data in each city, and presented the underlying infectivity networks for characterizing how dengue transmits from one location to another. The results showed that the communication of in-out infections with Guangzhou and Foshan could be responsible for the large-scale diffusion of dengue epidemics in Guangdong in 2014. Our findings can offer new insights into how to improve the predictability and risk assessment of dengue transmission.
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Affiliation(s)
- Guanghu Zhu
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China; Department of Medical Statistics and Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Jianpeng Xiao
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China
| | - Bing Zhang
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China
| | - Tao Liu
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China
| | - Hualiang Lin
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China
| | - Xing Li
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China
| | - Tie Song
- Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China
| | - Yonghui Zhang
- Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China
| | - Wenjun Ma
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China.
| | - Yuantao Hao
- Department of Medical Statistics and Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China.
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Liu T, Zhu G, He J, Song T, Zhang M, Lin H, Xiao J, Zeng W, Li X, Li Z, Xie R, Zhong H, Wu X, Hu W, Zhang Y, Ma W. Early rigorous control interventions can largely reduce dengue outbreak magnitude: experience from Chaozhou, China. BMC Public Health 2017; 18:90. [PMID: 28768542 PMCID: PMC5541667 DOI: 10.1186/s12889-017-4616-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Accepted: 07/20/2017] [Indexed: 01/03/2023] Open
Abstract
Background Dengue fever is a severe public heath challenge in south China. A dengue outbreak was reported in Chaozhou city, China in 2015. Intensified interventions were implemented by the government to control the epidemic. However, it is still unknown the degree to which intensified control measures reduced the size of the epidemics, and when should such measures be initiated to reduce the risk of large dengue outbreaks developing? Methods We selected Xiangqiao district as study setting because the majority of the indigenous cases (90.6%) in Chaozhou city were from this district. The numbers of daily indigenous dengue cases in 2015 were collected through the national infectious diseases and vectors surveillance system, and daily Breteau Index (BI) data were reported by local public health department. We used a compartmental dynamic SEIR (Susceptible, Exposed, Infected and Removed) model to assess the effectiveness of control interventions, and evaluate the control effect of intervention timing on dengue epidemic. Results A total of 1250 indigenous dengue cases was reported from Xiangqiao district. The results of SEIR modeling using BI as an indicator of actual control interventions showed a total of 1255 dengue cases, which is close to the reported number (n = 1250). The size and duration of the outbreak were highly sensitive to the intensity and timing of interventions. The more rigorous and earlier the control interventions implemented, the more effective it yielded. Even if the interventions were initiated several weeks after the onset of the dengue outbreak, the interventions were shown to greatly impact the prevalence and duration of dengue outbreak. Conclusions This study suggests that early implementation of rigorous dengue interventions can effectively reduce the epidemic size and shorten the epidemic duration.
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Affiliation(s)
- Tao Liu
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, No. 160, Qunxian Road, Panyu District, Guangzhou, 511430, China
| | - Guanghu Zhu
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, No. 160, Qunxian Road, Panyu District, Guangzhou, 511430, China
| | - Jianfeng He
- Guangdong Provincial Center for Disease Control and Prevention, No. 160, Qunxian Road, Panyu District, Guangzhou, 511430, China
| | - Tie Song
- Guangdong Provincial Center for Disease Control and Prevention, No. 160, Qunxian Road, Panyu District, Guangzhou, 511430, China
| | - Meng Zhang
- Guangdong Provincial Center for Disease Control and Prevention, No. 160, Qunxian Road, Panyu District, Guangzhou, 511430, China
| | - Hualiang Lin
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, No. 160, Qunxian Road, Panyu District, Guangzhou, 511430, China
| | - Jianpeng Xiao
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, No. 160, Qunxian Road, Panyu District, Guangzhou, 511430, China
| | - Weilin Zeng
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, No. 160, Qunxian Road, Panyu District, Guangzhou, 511430, China
| | - Xing Li
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, No. 160, Qunxian Road, Panyu District, Guangzhou, 511430, China
| | - Zhihao Li
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, No. 160, Qunxian Road, Panyu District, Guangzhou, 511430, China
| | - Runsheng Xie
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, No. 160, Qunxian Road, Panyu District, Guangzhou, 511430, China
| | - Haojie Zhong
- Guangdong Provincial Center for Disease Control and Prevention, No. 160, Qunxian Road, Panyu District, Guangzhou, 511430, China
| | - Xiaocheng Wu
- Guangdong Provincial Center for Disease Control and Prevention, No. 160, Qunxian Road, Panyu District, Guangzhou, 511430, China.,Faculty of Medical Statistics and Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, China
| | - Wenbiao Hu
- School of Public Health and Social Work & Institute of Health and Biomedical Innovation, Queensland University of Technology, QLD, Brisbane, Australia
| | - Yonghui Zhang
- Guangdong Provincial Center for Disease Control and Prevention, No. 160, Qunxian Road, Panyu District, Guangzhou, 511430, China.
| | - Wenjun Ma
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, No. 160, Qunxian Road, Panyu District, Guangzhou, 511430, China.
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