The clearing and settlement of tropical rainforests has exposed woodcutters, farmers, and ecotourists to new vector-borne diseases.

All are examples of ways that pathogens can spread. Coughing is an example of airborne droplet transmission; eating undercooked pork is an example of common vehicle transmission; a flea bite is an example of vector transmission; and breathing contaminated dust particles is an example of airborne transmission.

All are examples of ways that pathogens can spread. Coughing is an example of airborne droplet transmission; eating undercooked pork is an example of common vehicle transmission; a flea bite is an example of vector transmission; and breathing contaminated dust particles is an example of airborne transmission.

All are examples of ways that pathogens can spread. Coughing is an example of airborne droplet transmission; eating undercooked pork is an example of common vehicle transmission; a flea bite is an example of vector transmission; and breathing contaminated dust particles is an example of airborne transmission.

All are examples of ways that pathogens can spread. Coughing is an example of airborne droplet transmission; eating undercooked pork is an example of common vehicle transmission; a flea bite is an example of vector transmission; and breathing contaminated dust particles is an example of airborne transmission.

Today there are more antiviral drugs available for HIV than for any other viral disease, transforming an infection that was once considered a death sentence into a manageable chronic condition.

Today there are more antiviral drugs available for HIV than for any other viral disease, transforming an infection that was once considered a death sentence into a manageable chronic condition.

Today there are more antiviral drugs available for HIV than for any other viral disease, transforming an infection that was once considered a death sentence into a manageable chronic condition.

All of the above can help prevent infectious disease. Other behaviors, such as exercising caution around wild and unfamiliar domestic animals, avoiding insect bites, practicing safe sex, and being vigilant about disease threats while traveling abroad, can also reduce the risk of infection.

All of the above can help prevent infectious disease. Other behaviors, such as exercising caution around wild and unfamiliar domestic animals, avoiding insect bites, practicing safe sex, and being vigilant about disease threats while traveling abroad, can also reduce the risk of infection.

All of the above can help prevent infectious disease. Other behaviors, such as exercising caution around wild and unfamiliar domestic animals, avoiding insect bites, practicing safe sex, and being vigilant about disease threats while traveling abroad, can also reduce the risk of infection.

Most infectious diseases are impacted by changes in the environment. Malaria, dengue, and viral encephalitis infections, for example, are highly sensitive to environmental changes.

About one quarter of all deaths worldwide are caused by infectious disease. More than two-thirds of the deaths in children under the age of five are caused by infectious disease.

About one quarter of all deaths worldwide are caused by infectious disease. More than two-thirds of the deaths in children under the age of five are caused by infectious disease.

Trichinosis is not a viral disease. It is caused by a helminth (parasitic worm) found in undercooked meat, not by a virus. 

Trichinosis is not a viral disease. It is caused by a helminth (parasitic worm) found in undercooked meat, not by a virus.   

About ten trillion microbes live in the human gastrointestinal tract. They are essential for proper digestion and absorption of nutrients.

About ten trillion microbes live in the human gastrointestinal tract. They are essential for proper digestion and absorption of nutrients.

About ten trillion microbes live in the human gastrointestinal tract. They are essential for proper digestion and absorption of nutrients.

Since the beginning of the 20th century the number of people in the world has more than quadrupled—from 1.6 billion to nearly 7 billion—and world population is expected to rise to well over 9 billion by 2050.

Since the beginning of the 20th century the number of people in the world has more than quadrupled—from 1.6 billion to nearly 7 billion—and world population is expected to rise to well over 9 billion by 2050.