scholarly journals Bifurcation Analysis in Models for Vector-Borne Diseases with Logistic Growth

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Guihua Li ◽  
Zhen Jin
Keyword(s):  
Death Rate ◽  
Host Population ◽  
Backward Bifurcation ◽  
Logistic Growth ◽  
Natural Death ◽  
Vector Borne Diseases ◽  
Vector Population ◽  
Existence And Stability ◽  
Vector Borne ◽  
Parameter Varying

We establish and study vector-borne models with logistic and exponential growth of vector and host populations, respectively. We discuss and analyses the existence and stability of equilibria. The model has backward bifurcation and may have no, one, or two positive equilibria when the basic reproduction numberR0is less than one and one, two, or three endemic equilibria whenR0is greater than one under different conditions. Furthermore, we prove that the disease-free equilibrium is stable ifR0is less than 1, it is unstable otherwise. At last, by numerical simulation, we find rich dynamical behaviors in the model. By taking the natural death rate of host population as a bifurcation parameter, we find that the system may undergo a backward bifurcation, saddle-node bifurcation, Hopf bifurcation, Bogdanov-Takens bifurcation, and cusp bifurcation with the saturation parameter varying. The natural death rate of host population is a crucial parameter. If the natural death rate is higher, then the host population and the disease will die out. If it is smaller, then the host and vector population will coexist. If it is middle, the period solution will occur. Thus, with the parameter varying, the disease will spread, occur periodically, and finally become extinct.

scholarly journals Dynamics and Biocontrol: The Indirect Effects of a Predator Population on a Host-Vector Disease Model

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Fengyan Zhou ◽  
Hongxing Yao
Keyword(s):  
Disease Model ◽  
Transmitted Disease ◽  
Host Population ◽  
Uniform Persistence ◽  
Predator Population ◽  
Insect Vector ◽  
Vector Borne Diseases ◽  
Vector Population ◽  
Reproduction Numbers ◽  
Vector Borne

A model of the interactions among a host population, an insect-vector population, which transmits virus from hosts to hosts, and a vector predator population is proposed based on virus-host, host-vector, and prey (vector)-enemy theories. The model is investigated to explore the indirect effect of natural enemies on host-virus dynamics by reducing the vector densities, which shows the basic reproduction numbersR01(without predators) andR02(with predators) that provide threshold conditions on determining the uniform persistence and extinction of the disease in a host population. When the model is absent from predator, the disease is persistent ifR01>1; in such a case, by introducing predators of a vector, then the insect-transmitted disease will be controlled ifR02<1. From the point of biological control, these results show that an additional predator population of the vector may suppress the spread of vector-borne diseases. In addition, there exist limit cycles with persistence of the disease or without disease in presence of predators. Finally, numerical simulations are conducted to support analytical results.

scholarly journals Bayesian data assimilation provides rapid decision support for vector-borne diseases

2015 ◽  
Vol 12 (108) ◽  
pp. 20150367 ◽  
Author(s):  
Chris P. Jewell ◽  
Richard G. Brown
Keyword(s):  
Decision Support ◽  
Data Assimilation ◽  
Population Data ◽  
Disease Status ◽  
Host Population ◽  
Significant Advance ◽  
Model Parameters ◽  
Vector Borne Diseases ◽  
Vector Borne ◽  
Bayesian Data Assimilation

Predicting the spread of vector-borne diseases in response to incursions requires knowledge of both host and vector demographics in advance of an outbreak. Although host population data are typically available, for novel disease introductions there is a high chance of the pathogen using a vector for which data are unavailable. This presents a barrier to estimating the parameters of dynamical models representing host–vector–pathogen interaction, and hence limits their ability to provide quantitative risk forecasts. The Theileria orientalis (Ikeda) outbreak in New Zealand cattle demonstrates this problem: even though the vector has received extensive laboratory study, a high degree of uncertainty persists over its national demographic distribution. Addressing this, we develop a Bayesian data assimilation approach whereby indirect observations of vector activity inform a seasonal spatio-temporal risk surface within a stochastic epidemic model. We provide quantitative predictions for the future spread of the epidemic, quantifying uncertainty in the model parameters, case infection times and the disease status of undetected infections. Importantly, we demonstrate how our model learns sequentially as the epidemic unfolds and provide evidence for changing epidemic dynamics through time. Our approach therefore provides a significant advance in rapid decision support for novel vector-borne disease outbreaks.

scholarly journals A Dengue Vaccination Model for Immigrants in a Two-Age-Class Population

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Hengki Tasman ◽  
Asep K. Supriatna ◽  
Nuning Nuraini ◽  
Edy Soewono
Keyword(s):  
Disease Transmission ◽  
Disease Status ◽  
Host Population ◽  
Reproduction Ratio ◽  
Vaccination Programs ◽  
Vector Population ◽  
Dengue Transmission ◽  
Existence And Stability ◽  
Adult Classes ◽  
Disease Free

We develop a model of dengue transmission with some vaccination programs for immigrants. We classify the host population into child and adult classes, in regards to age structure, and into susceptible, infected and recovered compartments, in regards to disease status. Since migration plays important role in disease transmission, we include immigration and emigration factors into the model which are distributed in each compartment. Meanwhile, the vector population is divided into susceptible, exposed, and infectious compartments. In the case when there is no incoming infected immigrant, we obtain the basic reproduction ratio as a threshold parameter for existence and stability of disease-free and endemic equilibria. Meanwhile, in the case when there are some incoming infected immigrants, we obtain only endemic equilibrium. This indicates that screening for the immigrants is important to ensure the effectiveness of the disease control.

Community Perception Regarding Mosquito-Borne Diseases in Some Selected Areas of Ganjam District of Odisha State, India

2021 ◽  
pp. 0272684X2110049
Author(s):  
Sisir K Nayak ◽  
Surya N Swain ◽  
T Sarita Achari ◽  
Tapan K Barik
Keyword(s):  
Disease Incidence ◽  
Basic Knowledge ◽  
Health Concern ◽  
Mosquito Vector ◽  
College Level ◽  
Community Perception ◽  
Vector Borne Diseases ◽  
Vector Population ◽  
Vector Borne ◽  
Ganjam District

Mosquito-borne diseases are a major public health concern. Because of absence of effective therapy and vaccination to treat and prevent such vector-borne diseases, these initial cases have triggered strong concerns within medical communities, turning a bad dream into reality. To date, reducing the mosquito vector population remains the main strategy to control the transmission of mosquito borne diseases. In this connection, community-based perception recognized as an essential tool for long-term vector control management. In this study, a community perception survey was carried out in six selected study areas of Ganjam district of Odisha. A total of 3257 inhabitants from randomly chosen 600 no. of houses from 06 selected study areas were interviewed using a pre-tested structured questionnaire about various mosquito vector-borne diseases. As an outcome, we found that only 36% of people have basic knowledge and idea about vector-borne diseases, out of which only 14% know Anopheles as a causative agent whereas Aedes and Culex were very least concern. Regarding the source of knowledge, electronic media was the principal source of information, while the involvements of health personnel were least mentioned. Results of the current study indicates the necessity to plan health education program to bring important perceptions regarding vector-borne diseases at school and college level because the infrequent source of knowledge is the main cause of an increase in the disease incidence.

scholarly journals ENTOMOLOGICAL PARAMETERS AND CHARACTERIZATION OF INSECTICIDE RESISTANCE IN DENGUE VECTOR AEDES AEGYPTI LARVAE FROM BENGKULU CITY, INDONESIA

2021 ◽  
Vol 21 (1) ◽  
pp. 96-102
Author(s):  
Dessy Triana ◽  
Fitaloca N Siregar ◽  
Eka Purnama Wulan Tri Utami ◽  
Tatik Suteky ◽  
Swandito Wicaksono
Keyword(s):  
Aedes Aegypti ◽  
Cross Sectional ◽  
Vector Borne Diseases ◽  
Control Programs ◽  
Vector Population ◽  
Who 1999 Criteria ◽  
Vector Borne ◽  
Dengue Control ◽  
Breeding Place

In Bengkulu, as in other areas of Indonesia, dengue is one of the most important vector-borne diseases. The primary strategy to control dengue is by reducing the vector population using insecticides. However, applications of insecticides becomes a contributing factor in the development of vector resistance. As there is no effective dengue drug or safe vaccine available, vector control remains the most effective intervention to reduce incidence and prevent transmission and outbreak. This study aimed to determine the entomological parameters and resistance status to temephos of Aedes aegypti larvae from Lingkar Barat village and Jalan Gedang village (dengue endemic areas). This study used cross-sectional and experimental with post-control only design. The sampling refers to the guidelines for dengue entomology surveys according to WHO 1999 criteria. Aedes aegypti eggs were collected by ovitraps and reared to larvae stage. Susceptibility test of larvae to the temephos was estimated using standard WHO. Mortality of larvae Ae. aegypti after 24 hours with multiple concentration of temephos indicative of highly resistant.  Entomological parameters for house index (HI), container index (CI) and container pupa index (CPI) in Jalan Gedang village and Lingkar Barat village were estimated: 7%, 12% for HI and 1.97%, 3.43% for CI, and 5%, 2% for CPI, respectively. The proportion of controllable sites is higher than disposable sites, it has a high risk as breeding places for mosquitoes indicates a high potential risk as breeding place and transmission of dengue. Awareness sanitation in the home and surrounding environment must be possessed by each individual community in order to prevent and overcome the incidence of dengue. These data should be of value in formulating dengue control programs.

scholarly journals Clustered Breeding Sites: Shelters for Vector-Borne Diseases

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
J. C. A. Dias ◽  
L. H. A. Monteiro
Keyword(s):  
Host Population ◽  
Spatial Distributions ◽  
Breeding Sites ◽  
Vector Borne Diseases ◽  
Vector Abundance ◽  
Probabilistic Cellular Automaton ◽  
Time Variations ◽  
Vector Borne ◽  
Clustered Distributions ◽  
Homogeneous Distributions

Here, the propagation of vector-borne diseases is modeled by using a probabilistic cellular automaton. Numerical simulations considering distinct spatial distributions and time variations of the vector abundance are performed, in order to investigate their impacts on the number of infected individuals of the host population. The main conclusion is as follows: in the clustered distributions, the prevalence is lower, but the eradication is more difficult to be achieved, as compared to homogeneous distributions. This result can be relevant in the implementation of preventive surveillance measures.

scholarly journals What is known about modified insects for disease prevention?: a systematic review

2018 ◽  
Author(s):  
Teresa Nazareth ◽  
Isabel Craveiro ◽  
Alanny Moutinho ◽  
Cátia Gonçalves ◽  
Luzia Gonçalves ◽  
...  
Keyword(s):  
Systematic Review ◽  
Disease Prevention ◽  
Vector Borne Diseases ◽  
Promising Tool ◽  
Vector Population ◽  
Field Evidence ◽  
Vector Borne ◽  
Long Term Impact ◽  
Transgenic Mosquitoes

The modification and release of insects to suppress or replace natural insect vectors constitutes a promising tool for vector control and disease prevention, facing the unprecedented global emergence of vector-borne diseases. Little is known regarding these innovative modification strategies and available evidence is not standardized turning it difficult to reflect on their actual efficacy and eventual effects. This work conducted a systematic review, gathering and analyzing research articles from PubMed and Biblioteca Virtual em Saúde databases whose results directly report efficacy and effects of the use of modified insects for disease prevention until 2016. Within more than 1500 publications that were screened a total of 349 where analyzed. A total of 12/3.4% reported field-based evidence, and 41/11.7% covered modification stretagies’ efficacy after insects’ release, their epidemiology impact or its long-term efficacy. Examples of successful results were the replacement of natural field populations by wolbachia-infected mosquitoes in 5 weeks, and the elimination of a population in laboratory cages after transgenic mosquitoes release over 10–20 weeks. Variability in the effective results were described (90/25.7%) questioning its reproducibility in different settings. We also found 38/10.9% publications reporting reversal outcomes, such as an increase of vector population after release. Ecological effects such as horizontal transfer events to non-target species (54/15.5%), and wolbachia-induced worsening pathogenesis on mammal filarial diseases (10/2.9%) were also reported. Present work revealed promising outcomes of both suppressing and replacing approaches. However, it also revealed a need of field-based evidence mainly regarding epidemiologic and long-term impact of insect modification strategies. It pointed out some eventual irreversible and important effects that must not be ignored when considering open-field releases, and that may constitute constraints to generate the missing field evidence. Moreover, the level of variability of existing evidence suggests the need of local/specific evidence in each setting of an eventual release.

scholarly journals Transgenesis of Bioluminescence (BL) Gene and Its Potential Use for Malaria Residual Transmission Issue and Other Vector Borne Diseases: New Considerations for Vector and Vector Borne Diseases (VBD) Control

2021 ◽  
pp. 6-19
Author(s):  
G. Carnevale ◽  
P. Carnevale
Keyword(s):  
Green Fluorescent Protein ◽  
Vector Control ◽  
Fluorescent Protein ◽  
Breeding Site ◽  
Human Beings ◽  
Vector Borne Diseases ◽  
Vector Population ◽  
Mark Release Recapture ◽  
Vector Borne ◽  
Green Fluorescent

The present article considers the potential of transgenesis of the bioluminescent gene for malaria and other vector borne diseases (VBD) control. Vector control is an important component of every vector control operations for the vector borne disease control. Actually the bioluminescence phenomena and the green fluorescent protein GPF open great field of researches and “On December 10, 2008 Osamu Shimomura, Martin Chalfie and Roger Tsien were awarded the Nobel Prize in Chemistry for "the discovery and development of the green fluorescent protein, GFP". Bio-molecular technologies and transgenesis open the field for getting BL mosquitoes such as Plasmodium (several references) for “Transmission Reducing Activity” (TRA) without any hazard on human beings and ecological level. For exemple BL mosquitoes would be of paramount importance for mark-release-recapture becoming easier to implement and giving more relevant and reliable data on relation between density (size of the population) and distance (and wind) as the vector population size decrease with increasing distance from the source of production (breeding site) or release point. BL appeared already of great interest to understand the relation vector/parasite and to assess transmission intensity. Our idea is to genetically produce “Bioluminescent Mosquitoes” allowing a better identification of their presence, behavior, densities, infected specimens, risk of transmission before/after vector control operations which could be greatly improved thanks to the targeting of mosquitoes resting site or flight range and any other biological component.

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