Another result of rising temperatures is that infectious diseases once confined to warmer regions are expanding their reach. An analysis by the Centers for Disease Control and Prevention
concluded that the number of illnesses from mosquito, tick and flea bites doubled between 2004 and 2018. This includes Lyme disease, a tick-borne illness that can inflict permanent neurological harm if untreated, and West Nile disease, an infection spread by mosquitoes that led to at least 127 deaths
during an outbreak in the southwestern United States in 2021.
The risk of contracting malaria within the United States remains very low, but the occurrence of local transmission should be a sobering reminder that diseases associated with other parts of the world can affect us here as weather patterns change. Indeed, at least 200 infectious diseases
globally are exacerbated by climate hazards.