scholarly journals Human movement, cooperation and the effectiveness of coordinated vector control strategies

2017 ◽  
Vol 14 (133) ◽  
pp. 20170336 ◽  
Author(s):  
Chris M. Stone ◽  
Samantha R. Schwab ◽  
Dina M. Fonseca ◽  
Nina H. Fefferman
Keyword(s):  
Vector Control ◽  
Disease Transmission ◽  
Control Strategies ◽  
Virus Transmission ◽  
Human Movement ◽  
Vector Surveillance ◽  
Vector Borne Disease ◽  
Control Programmes ◽  
Vector Borne ◽  
Host Movement

Vector-borne disease transmission is often typified by highly focal transmission and influenced by movement of hosts and vectors across different scales. The ecological and environmental conditions (including those created by humans through vector control programmes) that result in metapopulation dynamics remain poorly understood. The development of control strategies that would most effectively limit outbreaks given such dynamics is particularly urgent given the recent epidemics of dengue, chikungunya and Zika viruses. We developed a stochastic, spatial model of vector-borne disease transmission, allowing for movement of hosts between patches. Our model is applicable to arbovirus transmission by Aedes aegypti in urban settings and was parametrized to capture Zika virus transmission in particular. Using simulations, we investigated the extent to which two aspects of vector control strategies are affected by human commuting patterns: the extent of coordination and cooperation between neighbouring communities. We find that transmission intensity is highest at intermediate levels of host movement. The extent to which coordination of control activities among neighbouring patches decreases the prevalence of infection is affected by both how frequently humans commute and the proportion of neighbouring patches that commits to vector surveillance and control activities. At high levels of host movement, patches that do not contribute to vector control may act as sources of infection in the landscape, yet have comparable levels of prevalence as patches that do cooperate. This result suggests that real cooperation among neighbours will be critical to the development of effective pro-active strategies for vector-borne disease control in today's commuter-linked communities.

Vector Control, Optimal Control, and Vector-Borne Disease Dynamics

2020 ◽  
pp. 267-288
Author(s):  
Michael B. Bonsall
Keyword(s):  
Optimal Control ◽  
Population Genetics ◽  
Population Dynamics ◽  
Vector Control ◽  
Cost Effective ◽  
Disease Suppression ◽  
Medical Interventions ◽  
Vector Borne Disease ◽  
Vector Borne

Understanding methods of vector control is essential to vector-borne disease (VBD) management. Vaccines or standard medical interventions for many VDBs do not exist or are poorly developed so disease control is focused on managing vector numbers and dynamics. This involves understanding not only the population dynamics but also the population genetics of vectors. Using mosquitoes as a case study, in this chapter, the modern genetics-based methods of vector control (self-limiting, self-sustaining) on mosquito population and disease suppression will be reviewed. These genetics-based methods highlight the importance of understanding the interplay between genetics and ecology to develop optimal, cost-effective solutions for control. The chapter focuses on how these genetics-based methods can be integrated with other interventions, and concludes with a summary of regulatory and policy perspectives about the use of these approaches in the management of VBDs.

scholarly journals Nextgen Vector Surveillance Tools: sensitive, specific, cost-effective and epidemiologically relevant

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Robert Farlow ◽  
Tanya L. Russell ◽  
Thomas R. Burkot
Keyword(s):  
Decision Making ◽  
Vector Control ◽  
Malaria Control ◽  
Cost Effective ◽  
Effective Control ◽  
Next Generation ◽  
Vector Data ◽  
Vector Surveillance ◽  
Current Vector ◽  
Control Programmes

Abstract Background Vector surveillance provides critical data for decision-making to ensure that malaria control programmes remain effective and responsive to any threats to a successful control and elimination programme. The quality and quantity of data collected is dependent on the sampling tools and laboratory techniques used which may lack the sensitivity required to collect relevant data for decision-making. Here, 40 vector control experts were interviewed to assess the benefits and limitations of the current vector surveillance tools and techniques. In addition, experts shared ideas on “blue sky” indicators which encompassed ideas for novel methods to monitor presently used indicators, or to measure novel vector behaviours not presently measured. Algorithms for deploying surveillance tools and priorities for understanding vector behaviours are also needed for collecting and interpreting vector data. Results The available tools for sampling and analysing vectors are often hampered by high labour and resource requirements (human and supplies) coupled with high outlay and operating costs and variable tool performance across species and geographic regions. The next generation of surveillance tools needs to address the limitations of present tools by being more sensitive, specific and less costly to deploy to enable the collection and use of epidemiologically relevant vector data to facilitate more proactive vector control guidance. Ideas and attributes for Target Product Profiles (TPPs) generated from this analysis provide targets for research and funding to develop next generation tools. Conclusions More efficient surveillance tools and a more complete understanding of vector behaviours and populations will provide a basis for more cost effective and successful malaria control. Understanding the vectors’ behaviours will allow interventions to be deployed that target vulnerabilities in vector behaviours and thus enable more effective control. Through defining the strengths and weaknesses of the current vector surveillance methods, a foundation and initial framework was provided to define the TPPs for the next generation of vector surveillance methods. The draft TTPs presented here aim to ensure that the next generation tools and technologies are not encumbered by the limitations of present surveillance methods and can be readily deployed in low resource settings.

The effectiveness of pre-impregnated permethrin in military clothing in the prevention of insect bites

2018 ◽  
Vol 104 (2) ◽  
pp. 80-83
Author(s):  
D Biggs
Keyword(s):  
Disease Transmission ◽  
Integrated Approach ◽  
Negative Control ◽  
Vector Borne Disease ◽  
Volunteer Study ◽  
Significant Difference ◽  
Insect Mortality ◽  
Alternative Means ◽  
Vector Borne ◽  
Insect Bites

AbstractIntroductionWhen on operational deployment, or where a vector-borne disease threat has been identified, military personnel wear uniform that has been pre-impregnated with permethrin insecticide to prevent insect bites, as part of an integrated approach to bite avoidance in order to reduce disease non-battle injury. This article reports a study that was carried out to investigate whether the clothing treatments currently in use are effective at preventing insect bites.MethodsA human volunteer study was conducted using two different species of mosquito and clothing subjected to different washing schedules. The number of landing events and probing events, and insect mortality, were recorded.ResultsThere was a marked increase in mosquito activity as the amount of viable permethrin was reduced through washing. There was a statistically significant difference between 50 washes and the negative control, and between 50 and 5 washes. As clothing is increasingly washed, its effectiveness is reduced.ConclusionThe use of pre-impregnated uniform does not provide complete protection against biting insects throughout the life of the garment. No single means of protection will prevent personnel from being bitten, and a suite of personal and communal measures should be employed to reduce the risk of vector-borne disease, including the use of insect repellent, mosquito nets, anti-malarial chemoprophylaxis and re-treatment of clothing against biting insects in order to reduce the risk of disease transmission. Since this study, alternative means of clothing treatment have been sought to reinforce the pre-treated uniforms issued. Advice and direction is available, specific to the environment personnel are deploying to, based upon risk.

scholarly journals PO 8505 LEISHMANIASIS IN ANGOLA – AN EMERGING DISEASE?

2019 ◽  
Vol 4 (Suppl 3) ◽  
pp. A47.3-A48
Author(s):  
Sofia Cortes ◽  
André Pereira ◽  
Jocelyne Vasconcelos ◽  
Joana P Paixão ◽  
Joltim Quivinja ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Neglected Tropical Diseases ◽  
Epidemiological Studies ◽  
Sequencing Analysis ◽  
Vector Borne Disease ◽  
Health Authorities ◽  
African Patient ◽  
Control Programmes ◽  
Vector Borne ◽  
The Impact

BackgroundPoverty, lack of resources, inadequate treatments and control programmes exacerbate the impact of infectious diseases in the developing world. Leishmaniasis is a vector-borne disease that is among the ten major neglected tropical diseases. Although endemic in more than 90 countries, the ones most affected, representing over 90% of new cases, are Bangladesh, Brazil, Ethiopia, India, Kenya, Nepal, and Sudan. In Africa south of the equator, the impact of leishmaniasis is much lower. In several countries, like Angola, little is known about this infectious neglected disease. In the 1970s, a group of Portuguese researchers described three cases of cutaneous leishmaniasis in children from Huambo district and in the 1990s visceral leishmaniasis was diagnosed in an African patient. More recently a canine survey in Luanda revealed two Leishmania-infected dogs.After some suspected cases of human cutaneous leishmaniasis in Huambo region in 2017, the Angola health authorities and the Instituto de Higiene e Medicina Tropical (IHMT), Lisbon, Portugal, established a collaboration to analyse samples from some suspected cases.MethodsThree paraffin-embedded human skin samples from dermatological lesions were sent to IHMT for molecular analysis. After DNA extraction, PCR was performed by using four protocols with different molecular markers.ResultsOne PCR protocol using a nested approach was positive in two of the samples. Sequencing analysis confirmed Leishmania sp. DNA.ConclusionThis was the first time that suspected human cutaneous samples were screened for leishmaniasis by molecular methods with detection of Leishmania sp. DNA. These preliminary studies highlight the need for higher awareness of health professionals for leishmaniasis clinical forms, to recognise risk factors and the epidemiological features of leishmaniasis in the Huambo province. It would be relevant to perform further epidemiological studies to confirm if this vector-borne disease could be emergent in this country.

scholarly journals Assessment of the Public Health Threats Posed by Vector-Borne Disease in the United Kingdom (UK)

2018 ◽  
Vol 15 (10) ◽  
pp. 2145 ◽  
Author(s):  
Jolyon Medlock ◽  
Kayleigh Hansford ◽  
Alexander Vaux ◽  
Ben Cull ◽  
Emma Gillingham ◽  
...  
Keyword(s):  
Public Health ◽  
United Kingdom ◽  
Disease Risk ◽  
Surveillance Systems ◽  
Mosquito Vector ◽  
Vector Surveillance ◽  
Vector Borne Disease ◽  
The United Kingdom ◽  
Vector Borne ◽  
The Uk

In recent years, the known distribution of vector-borne diseases in Europe has changed, with much new information also available now on the status of vectors in the United Kingdom (UK). For example, in 2016, the UK reported their first detection of the non-native mosquito Aedes albopictus, which is a known vector for dengue and chikungunya virus. In 2010, Culex modestus, a principal mosquito vector for West Nile virus was detected in large numbers in the Thames estuary. For tick-borne diseases, data on the changing distribution of the Lyme borreliosis tick vector, Ixodes ricinus, has recently been published, at a time when there has been an increase in the numbers of reported human cases of Lyme disease. This paper brings together the latest surveillance data and pertinent research on vector-borne disease in the UK, and its relevance to public health. It highlights the need for continued vector surveillance systems to monitor our native mosquito and tick fauna, as well as the need to expand surveillance for invasive species. It illustrates the importance of maintaining surveillance capacity that is sufficient to ensure accurate and timely disease risk assessment to help mitigate the UK’s changing emerging infectious disease risks, especially in a time of climatic and environmental change and increasing global connectivity.

scholarly journals Temperature explains broad patterns of Ross River virus transmission

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Marta Strecker Shocket ◽  
Sadie J Ryan ◽  
Erin A Mordecai
Keyword(s):  
Disease Transmission ◽  
Pacific Islands ◽  
Nonlinear Models ◽  
Mechanistic Model ◽  
Virus Transmission ◽  
Thermal Response ◽  
Ross River Virus ◽  
Vector Borne ◽  
High And Low Temperatures ◽  
The Tropics

Thermal biology predicts that vector-borne disease transmission peaks at intermediate temperatures and declines at high and low temperatures. However, thermal optima and limits remain unknown for most vector-borne pathogens. We built a mechanistic model for the thermal response of Ross River virus, an important mosquito-borne pathogen in Australia, Pacific Islands, and potentially at risk of emerging worldwide. Transmission peaks at moderate temperatures (26.4°C) and declines to zero at thermal limits (17.0 and 31.5°C). The model accurately predicts that transmission is year-round endemic in the tropics but seasonal in temperate areas, resulting in the nationwide seasonal peak in human cases. Climate warming will likely increase transmission in temperate areas (where most Australians live) but decrease transmission in tropical areas where mean temperatures are already near the thermal optimum. These results illustrate the importance of nonlinear models for inferring the role of temperature in disease dynamics and predicting responses to climate change.

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