Any disease transmitted from an infected person to a non-infected person is a transmissive disease.
Insects like mosquitoes, lice, fleas, bed bugs, and ticks can transmit many diseases caused by infectious agents.
Viral diseases like chikungunya, yellow fever, dengue fever, etc, bacterial diseases like Lyme disease, plague, etc, protozoan diseases like malaria, sleeping sickness, leishmaniasis, filariasis, etc are transmitted through an insect.
There are various transmission routes for these diseases:
Airborne transmission – very small dry and wet particles that stay in the air for long periods, allowing airborne contamination even after the host's departure. Particle size < 5 μm.
Droplet transmission: droplets are usually wet particles that stay in the air for a short period. Contamination usually occurs in the presence of the host. Particle size > 5 μm. Examples: Ccommon cold, Coronavirus infection, etc.
Direct physical contact: touching an infected individual, including sexual contact. Examples: AIDS (acquired immunodeficiency syndrome) caused due to HIV (human immunodeficiency virus)
Indirect physical contact: touching a contaminated surface, including soil (fomite).
Faecal–oral transmission: from unwashed hands, contaminated food or water sources due to lack of sanitation and hygiene. Examples: Giardia, Cholera.