mosquito control
The Economics of Malaria
In the 2022 World Malaria Report, compiled by the World Health Organization (WHO), the total spend on funding the fight of malaria in 2021 was estimated at USD 3.5 billion. Over that year, the same report states that there were an estimated 247 million cases of malaria and 619,000 malaria deaths globally.
More recently, over the course of the 20th Century, malaria is believed to have claimed between 150–300 million lives. The disease is contracted predominantly in the tropical regions: sub-Saharan Africa, Asia and the Amazon basin. This is due to the prevalence of the Anopheles mosquito that transmits the disease. Poorer regions of Africa bear the vast majority of the burden. In 2021, around 95% of the diagnosed cases and deaths were on the African continent, 80% of which were children under the age of five. The disease is entirely preventable and curable with prompt diagnosis and effective methods of treatment which require sufficient investment and funding.
How Climate Change is Spreading Malaria in Africa
Warming temperatures are chasing animals and plants to new habitats, sometimes with devastating consequences to ecosystems. But there is little evidence regarding how far and how fast the invaders might be moving.
A new study offers a glimpse of the future by looking to the past. Mosquitoes that transmit malaria in sub-Saharan Africa have moved to higher elevations by about 6.5 meters (roughly 21 feet) per year and away from the Equator by 4.7 kilometers (about three miles) per year over the past century, according to the study.
Deforestation’s Hidden Toll: Amplifying Disease Risk Worldwide
In the last couple of decades, the lush rainforest around the remote village of Meliandou in the heart of Guinea has become patchier. Animals, like bats, saw their habitats dwindle and in a quest for survival, they sought refuge in closer proximity to human environments, making the boundaries between species thinner. A hollowed-out tree in the middle of the village became home to a colony of bats.
About 50 meters from the same tree, in the heart of Meliandou, a two-year-old boy named Emile lived with his family. In a matter of days, Emile fell ill with an unknown virus, developed a high fever, and died. Soon the same virus, that scientists now believe Emile got from the bats, took the lives of his sister, mother, and grandmother. The village, surrounded by a ring of forest, unexpectedly became the epicenter of a devastating outbreak that would leave an indelible mark.
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.
Vector-borne Diseases & Climate Change
Climate change creates new risks, particularly in the United States, for human exposure to vector-borne diseases (VBDs) — diseases which are transmitted to humans through the bites of insects (referred to as vectors) that carry the disease-causing pathogens. Common vectors include mosquitoes, ticks, and flies.
Climate change creates new uncertainties about the spread of VBDs such as the Zika virus, dengue fever, malaria, and Lyme disease by altering conditions that affect the development and dynamics of the disease vectors and the pathogens they carry.
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.
Study: Digitally Managed Larviciding
A new study has found that larval source management (LSM) – treating mosquito breeding habitats – can still be effective in malaria elimination operations, especially with the aid of new digital technologies. LSM has been replaced in Africa by long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS), but these methods are becoming less effective due to mosquitoes’ growing resistance to insecticides.
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.