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Routes of Transmission
Communicable and infectious diseases are spread in many different ways.

Understanding how diseases spread makes them easier to control and prevent.

Airborne transmission

Airborne transmission occurs when infectious agents are carried by dust suspended in the air. With airborne transmission, direct contact is not needed to spread disease (as compared with respiratory droplet transmission).

Respiratory (droplet) transmission

Some disease-causing bacteria and viruses are carried in the mouth, nose, throat and respiratory tree. They can spread by coming into direct contact with droplets when an infected person coughs or sneezes, or through saliva or mucus on unwashed hands. Browse the links below to learn about some of the diseases spread in this way.

Sexually transmitted diseases (STDs)

Sexually transmitted diseases are Oregon's most frequently reported infections and account for almost two-thirds of all reportable diseases.

Animal or insect transmission

Many microbes that threaten public health are carried by animals or insects and transmitted to humans. Visit the links below to read about these organisms, which animals carry them, and the illnesses they cause.

Food or water transmission

Food and water are necessary for life, but also prone to contamination with harmful microbes. The links below highlight prevention tips and efforts aimed at minimizing risks from foodborne and waterborne pathogens. 

Health care transmission

Doctors and hospitals are where the sick people go, but unfortunately, some infections may be transmitted in these settings. From the links below you can find data on healthcare-acquired infections in Oregon and rules related to the handling of potentially infectious medical waste.