It highlights selected examples involving both viral and parasitic diseases such as arboviruses, malaria, leishmaniasis, filariasis, Chagas disease, and schistosomiasis whose transmission patterns have been either directly or indirectly altered by the destruction of tropical forests.Deforestation results from a wide range of human activities, including settlement expansion, government-driven transmigration schemes, commercial logging, cultivation of cash crops, mining operations, hydropower projects, and the harvesting of fuel wood. Each of these activities influences how frequently vector-borne diseases occur, how widely they spread, and where they are concentrated geographically.The review focuses on three major regions: South America, West and Central Africa, and Southeast Asia. In each of these areas, documented shifts in vector behaviour, habitat use, and disease transmission patterns have been observed. These changes stem from human activities occurring at the boundary between forests and human settlements as well as from activities within the forests themselves. They arise not only from forest destruction but also from reforestation efforts.In South America, for instance, deforestation and related activities have created favourable habitats for *Anopheles darlingi* mosquitoes, triggering malaria outbreaks. In Southeast Asia, forest clearing has affected various mosquito species complexes such as A. dirus, A. minimus, and A. balabacensis each responding differently, leading to varied impacts on malaria transmission.The spread of leishmaniasis in South America has also been shaped by how some originally zoophilic sandfly species have adapted to feeding on humans and living near or around human dwellings. Several species, including Lutzomyia intermedia, Lu. longipalpis, and Lu. whitmani, once restricted to wild habitats, have shifted to peridomestic and even peri-urban environments.Shifts in disease patterns are further influenced by changes in the behaviour of animal reservoir hosts and by the capacity of pathogens to infect new hosts in the altered landscapes. For diseases in which humans serve as the main reservoir such as those caused by Plasmodium, Onchocerca, and Wuchereria detecting changes linked to deforestation can be more challenging. Understanding vector ecology in relation to climate changes triggered by forest loss therefore requires detailed knowledge of vector species and their complexes. The distributions of the Anopheles gambiae and Simulium damnosum species complexes in West Africa illustrate this need. Long-term studies of A. gambiae across different ecological zones and chromosome-based identification of "S. damnosum" forms in the Onchocerciasis Control Programme have been crucial for detecting shifts associated with habitat change.These cases emphasize the importance of carrying out taxonomic research on medically significant insects alongside continuous monitoring of changing environments. In some situations, the destruction of forests has reduced or removed disease transmission entirely for example, the elimination of S. neavei transmitted onchocerciasis in Kenya. However, as deforestation persists, even if at a slower pace, public health systems are likely to face uncertain, sometimes rapid, shifts in disease transmission patterns.