Disease Transmission

Epidemiologists study many different diseases. The most important factor in preventing the spread of disease is understanding how the disease is transmitted from one person to another within a population. Communicable (or spreadable) diseases are grouped into three categories. Use the tabs to explore how each type of disease moves through a population.

Vector-borne diseases are infections/diseases that are carried and transmitted into one living organism (human) by other (insects). This is mainly done by arthropods (such as fleas, flies, lice, mosquitoes, and ticks) through hematophagy- or feeding on blood. Some examples of vector-borne diseases are Dengue Fever, Lyme Disease, and West Nile Virus.

Airborne diseases are caused by infectious agents, known as pathogens, which are transmitted through the air. These pathogens are viruses, bacteria, and fungi and can be transmitted through any activities that generate aerosol particles (dust and air pollution) or water droplets (sneezing and coughing). Allergens/pathogens can cause inflammation in the nose, throat, sinus, and lungs. Some examples of airborne diseases are the common cold, flu, tuberculosis, and chicken pox. Temperature and humidity impact the efficacy of airborne diseases, while rainfall, sunshine, winds and extreme events (hurricanes) are also contributing factors.

Waterborne diseases are those that are largely transmitted through contact or consumption of water. These diseases include bacteria, parasites, and viruses. Sometimes, the infection can be introduced into the water and transmitted to the person or animal. Examples of this type are Vibrio, SARS, and E.coli.