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How do coughs and sneezes spread infectious droplets to another person’s eyes, nose, or mouth?

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Diagram showing the West Nile virus transmission cycle: a mosquito bites an infected bird (the primary reservoir host), then transmits the virus to humans or horses (incidental hosts) through subsequent bites. — infectious disease Birds are the primary reservoirs of West Nile virus. The virus is transmitted to humans and horses by mosquitoes that have bitten infected birds.

Infectious diseases are spread through droplet transmission, a process where large, heavy respiratory droplets containing an infectious agent are expelled when an infected person coughs or sneezes.1

These droplets travel through the air and can land directly on the mucous membranes—specifically the eyes, nose, or mouth—of another person nearby. Because these droplets are heavy, they typically do not remain suspended in the air for long distances, which is why close proximity to a contagious individual significantly increases the risk of infection.123

Additionally, these droplets may settle on surfaces, creating a secondary route of transmission known as fomite contact. If a person touches a contaminated surface and subsequently touches their own eyes, nose, or mouth, the infectious agent can enter the body. Maintaining hygiene and physical distance is essential to preventing the spread of these pathogens and protecting public health.32