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 The effect of resource limitation on the temperature dependence of mosquito population fitness

2021 ◽  
Vol 288 (1949) ◽  
Author(s):  
Paul J. Huxley ◽  
Kris A. Murray ◽  
Samraat Pawar ◽  
Lauren J. Cator
Keyword(s):  
Disease Transmission ◽  
Resource Limitation ◽  
Adult Size ◽  
Population Modelling ◽  
Juvenile Mortality ◽  
Low Resource ◽  
Vector Borne Disease ◽  
High Resource ◽  
Optimal Resource ◽  
Vector Borne

Laboratory-derived temperature dependencies of life-history traits are increasingly being used to make mechanistic predictions for how climatic warming will affect vector-borne disease dynamics, partially by affecting abundance dynamics of the vector population. These temperature–trait relationships are typically estimated from juvenile populations reared on optimal resource supply, even though natural populations of vectors are expected to experience variation in resource supply, including intermittent resource limitation. Using laboratory experiments on the mosquito Aedes aegypti , a principal arbovirus vector, combined with stage-structured population modelling, we show that low-resource supply in the juvenile life stages significantly depresses the vector's maximal population growth rate across the entire temperature range (22–32°C) and causes it to peak at a lower temperature than at high-resource supply. This effect is primarily driven by an increase in juvenile mortality and development time, combined with a decrease in adult size with temperature at low-resource supply. Our study suggests that most projections of temperature-dependent vector abundance and disease transmission are likely to be biased because they are based on traits measured under optimal resource supply. Our results provide compelling evidence for future studies to consider resource supply when predicting the effects of climate and habitat change on vector-borne disease transmission, disease vectors and other arthropods.

scholarly journals The impact of industrial activities on vector-borne disease transmission

Acta Tropica ◽  
2018 ◽  
Vol 188 ◽  
pp. 142-151 ◽  
Author(s):  
Robert T. Jones ◽  
Lucy S. Tusting ◽  
Hugh M.P. Smith ◽  
Sylvester Segbaya ◽  
Michael B. Macdonald ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Industrial Activities ◽  
Vector Borne Disease ◽  
Vector Borne ◽  
The Impact

scholarly journals Assessing the potential impact of vector-borne disease transmission following heavy rainfall events: a mathematical framework

2019 ◽  
Vol 374 (1775) ◽  
pp. 20180272 ◽  
Author(s):  
G. Chowell ◽  
K. Mizumoto ◽  
J. M. Banda ◽  
S. Poccia ◽  
C. Perrings
Keyword(s):  
Disease Transmission ◽  
Disease Outbreaks ◽  
Theme Issue ◽  
Rainfall Events ◽  
Transmission Season ◽  
Vector Borne Disease ◽  
Infectious Disease Outbreaks ◽  
Vector Borne ◽  
The Impact ◽  
Heavy Rainfall Events

Predicting the impact of natural disasters such as hurricanes on the transmission dynamics of infectious diseases poses significant challenges. In this paper, we put forward a simple modelling framework to investigate the impact of heavy rainfall events (HREs) on mosquito-borne disease transmission in temperate areas of the world such as the southern coastal areas of the USA. In particular, we explore the impact of the timing of HREs relative to the transmission season via analyses that test the sensitivity of HRE-induced epidemics to variation in the effects of rainfall on the dynamics of mosquito breeding capacity, and the intensity and temporal profile of human population displacement patterns. The recent Hurricane Harvey in Texas motivates the simulations reported. Overall, we find that the impact of vector-borne disease transmission is likely to be greater the earlier the HREs occur in the transmission season. Simulations based on data for Hurricane Harvey suggest that the limited impact it had on vector-borne disease transmission was in part because of when it occurred (late August) relative to the local transmission season, and in part because of the mitigating effect of the displacement of people. We also highlight key data gaps related to models of vector-borne disease transmission in the context of natural disasters. This article is part of the theme issue ‘Modelling infectious disease outbreaks in humans, animals and plants: approaches and important themes’. This issue is linked with the subsequent theme issue ‘Modelling infectious disease outbreaks in humans, animals and plants: epidemic forecasting and control’.

scholarly journals Microclimatic temperatures increase the potential for vector-borne disease transmission in the Scandinavian climate

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Najmul Haider ◽  
Carsten Kirkeby ◽  
Birgit Kristensen ◽  
Lene Jung Kjær ◽  
Jens Havskov Sørensen ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Vector Borne Disease ◽  
Vector Borne

scholarly journals Climatological, virological and sociological drivers of current and projected dengue fever outbreak dynamics in Sri Lanka

2020 ◽  
Vol 17 (167) ◽  
pp. 20200075 ◽  
Author(s):  
Caroline E. Wagner ◽  
Milad Hooshyar ◽  
Rachel E. Baker ◽  
Wenchang Yang ◽  
Nimalan Arinaminpathy ◽  
...  
Keyword(s):  
Sri Lanka ◽  
Dengue Virus ◽  
Disease Transmission ◽  
Temporal Dynamics ◽  
Sir Model ◽  
Extreme Weather Events ◽  
Climate Projections ◽  
Vector Borne Disease ◽  
Virus Serotype ◽  
Vector Borne

The largest ever Sri Lankan dengue outbreak of 2017 provides an opportunity for investigating the relative contributions of climatological, epidemiological and sociological drivers on the epidemic patterns of this clinically important vector-borne disease. To do so, we develop a climatologically driven disease transmission framework for dengue virus using spatially resolved temperature and precipitation data as well as the time-series susceptible-infected-recovered (SIR) model. From this framework, we first demonstrate that the distinct climatological patterns encountered across the island play an important role in establishing the typical yearly temporal dynamics of dengue, but alone are unable to account for the epidemic case numbers observed in Sri Lanka during 2017. Using a simplified two-strain SIR model, we demonstrate that the re-introduction of a dengue virus serotype that had been largely absent from the island in previous years may have played an important role in driving the epidemic, and provide a discussion of the possible roles for extreme weather events and human mobility patterns on the outbreak dynamics. Lastly, we provide estimates for the future burden of dengue across Sri Lanka using the Coupled Model Intercomparison Phase 5 climate projections. Critically, we demonstrate that climatological and serological factors can act synergistically to yield greater projected case numbers than would be expected from the presence of a single driver alone. Altogether, this work provides a holistic framework for teasing apart and analysing the various complex drivers of vector-borne disease outbreak dynamics.

scholarly journals Effects of complexity and seasonality on backward bifurcation in vector–host models

2018 ◽  
Vol 5 (2) ◽  
pp. 171971 ◽  
Author(s):  
Shakir Bilal ◽  
Edwin Michael
Keyword(s):  
Disease Transmission ◽  
Backward Bifurcation ◽  
Epidemiological Models ◽  
Seasonal Fluctuations ◽  
Complex Vector ◽  
Vector Borne Disease ◽  
Force Of Infection ◽  
Vector Borne ◽  
The Stability ◽  
Disease Free

We study implications of complexity and seasonality in vector–host epidemiological models exhibiting backward bifurcation. Vector–host diseases represent complex infection systems that can vary in the transmission processes and population stages involved in disease progression. Seasonal fluctuations in external forcing factors can also interact in a complex way with internal host factors to govern the transmission dynamics. In backward bifurcation, the insufficiency of R 0  < 1 for predicting the stability of the disease-free equilibrium (DFE) state arises due to existence of bistability (coexisting DFE and endemic equilibria) for a range of R 0 values below one. Here we report that this region of bistability decreases with increasing complexity of vector-borne disease transmission as well as with increasing seasonality strength. The decreases in the bistability region are accompanied by a reduced force of infection acting on primary hosts. As a consequence, we show counterintuitively that a more complex vector-borne disease may be easier to control in settings of high seasonality.

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