Editing Environmental and Public Health (section)

=== Range Expansion and Climate Envelopes ===
Historically, the transmission of severe vector-borne diseases like malaria and dengue fever was largely confined to tropical and subtropical regions, limited by cold winters that would kill off vector populations. As global temperatures rise, the "climate envelopes" suitable for these organisms are expanding poleward and into higher altitudes. Regions that were previously too cold to sustain populations of ''Aedes aegypti'' or ''Aedes albopictus'' mosquitoes (the primary vectors for dengue, Zika, and chikungunya) or ''Ixodes'' ticks (vectors for Lyme disease) are now becoming endemic zones.