dengue
Mosquito-borne Diseases & the Environment
Climate change and human activity are enabling the spread of mosquito-borne diseases, like dengue fever, to new places. Stanford infectious disease experts and disease ecologists discuss what we know and how communities can protect themselves from these changing disease threats.
Aedes aegypti: Beyond the Black and White
One look at Aedes aegypti gives an immediate impression of its menacing nature. The telltale dark and white bands on the mosquito’s legs and other body parts bring a sense of foreboding and hardship. Sleek, silent, and stealthy, Ae. aegypti is the primary vector for several important, debilitating, and sometimes fatal human diseases including dengue, Zika virus, yellow fever, and chikungunya. The species is cause for mounting concern on many levels, as its biology, behavior, and ability to adapt have made Aedes aegypti one of the most pervasive and daunting public health challenges in the modern world.
The first mosquito ever associated with the spread of disease, Ae. aegypti is also the most studied of all mosquito species.1 From its humble beginnings in the African wild to a footprint that spans the globe, this durable and opportunistic insect has become a formidable opponent of vector control efforts worldwide.
Tracking the Global Burden of Vector-Borne Disease
The burden of vector-borne diseases (VBDs) is one of public health’s most pressing challenges. VBDs are caused by pathogens such as arboviruses (arthropod-borne virus), bacteria, and parasites that are transmitted to humans and animals through the bites of infected arthropods including mosquitoes, ticks, sandflies, and fleas, among others. According to the World Health Organization (WHO) , “vector-borne diseases account for more than 17% of all infectious diseases, causing more than 700,000 deaths annually worldwide”.
Beyond these broad statistics, attempts to quantify the global burden of VBDs is extremely challenging – for a number of reasons. At the highest level, even “burden” has an underlying complexity in public health terms: burden may refer to the number of cases of a given disease as well as the number of deaths.
Burden can also represent Disability-adjusted Life Years (DALYs), a measure that accounts for the long-term effects of disability among the afflicted, as well as the economic impact of disease from regions and countries all the way down to households and individuals. These economic impacts can be further scrutinized as reduced productivity among the populace, increased healthcare costs, and negative impacts on tourism; all of which can directly affect the GDP and economic growth of local and regional economies. And that’s just the beginning.
Resistance in the Limelight
Doctor Shinji Kasai’s recent publication on the combined effects of three knockdown resistance (kdr) mutations in Aedes aegypti sparked media frenzy. He demonstrated the causal relationship between specific genes & pyrethroid sensitivity in mosquitoes.
The study improved understanding of insecticide resistance evolution & opened new strategies to control mosquito populations & reduce disease spread. Kasai’s latest paper on super-insecticide-resistant dengue mosquitoes caused a stir in the media, revealing high levels of pyrethroid resistance in field populations.
The Economics of Resistance
It would be extremely difficult to calculate, with any high degree of accuracy, the global economic impact of insecticide resistance. For starters, we must consider that insect management plays a pivotal role in a variety of sectors – agriculture, home and garden, forestry, structural applications, and vector control. Analysis of the totality of economic impacts arising from resistance in any one of these sectors quickly becomes a complicated interplay of variables that interact within that given system.
Battle in the Upper Keys
FKMCD hoping to turn the tide in the first major outbreak of dengue since 2010 As the world remains embattled with COVID-19 and the unprecedented …
What Happened with Zika
Five powerful positives that emerged in the wake of the 2016 Zika outbreakThink back two years to 2016. Never a day went by when there …
Predicting Public Health Risks with Satellite Imaging
Model predicts 63% of within-city dengue variance With ever-evolving technologies, there is growing amount of data to be interpreted. Of this data, satellite images are …
Full-Scale Assault Now Under Way as Key West District Battles Dengue
Swarms of them come from near and far, creating a furor in Key West, Florida. “They” are not mosquitoes. They are representatives of the national …
California takes a Proactive Approach to Managing Resistance Issues
Insecticide resistance is among the most challenging issues facing public health professionals, not only in California but around the world. As disease pressure increases, so …