Mosquitoes are the deadliest animals to humans—over 700,000 deaths occur annually worldwide from mosquito-borne diseases.
_Anopheles_ mosquitoes transmit malaria; in 2022, there were approximately 249 million cases globally and about 608,000 deaths, 95% of them in Africa, mostly children under five.
_Aedes_ mosquitoes (primarily _Aedes aegypti_ and _Aedes albopictus_) transmit dengue fever (an estimated 390 million infections per year), Zika virus (associated with the 2015–2016 outbreak in Brazil and linked to neonatal microcephaly), chikungunya, and yellow fever.
_Culex_ mosquitoes transmit West Nile fever, Japanese encephalitis (about 68,000 cases annually, mainly in East and South Asia), and lymphatic filariasis (elephantiasis, with around 120 million people infected globally).
Malaria remains the world's most severe mosquito-borne disease, but dengue is the fastest growing—the incidence of dengue has increased 30-fold over the past 50 years, primarily due to urbanization, increased international travel, and climate change.
In China, local transmission of dengue occurs in southern provinces like Guangdong, Yunnan, and Fujian, primarily transmitted by _Aedes albopictus_.