White blood cells are not a type of infectious agent. Part of the immune system, white blood cells fight infection rather than cause it. 

White blood cells are not a type of infectious agent. Part of the immune system, white blood cells fight infection rather than cause it. 

White blood cells are not a type of infectious agent. Part of the immune system, white blood cells fight infection rather than cause it. 

Lower respiratory tract infections (including pneumonia) kill more children worldwide than any other infectious disease. Together these diseases are the five leading causes of infectious disease worldwide, accounting for nearly one-fifth of all deaths.

Lower respiratory tract infections (including pneumonia) kill more children worldwide than any other infectious disease. Together these diseases are the five leading causes of infectious disease worldwide, accounting for nearly one-fifth of all deaths.

Lower respiratory tract infections (including pneumonia) kill more children worldwide than any other infectious disease. Together these diseases are the five leading causes of infectious disease worldwide, accounting for nearly one-fifth of all deaths.

Lower respiratory tract infections (including pneumonia) kill more children worldwide than any other infectious disease. Together these diseases are the five leading causes of infectious disease worldwide, accounting for nearly one-fifth of all deaths.

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.

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.

Growing evidence does suggest that infections are behind many chronic diseases once thought to be caused by genetic, environmental, or lifestyle factors, including peptic ulcers and cervical, liver, and gastric cancers.

The above describes how vaccines work. Antibiotics work by either killing bacteria or stopping them from reproducing, allowing the body's natural defenses to eliminate the pathogens.

Our bodies contain at least 10 times more bacterial cells than human cells. 

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.   

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.

The expanded use of cell phones does not have an impact on the spread of infectious disease. Climate change, ecosystem disturbances, war, poverty, migration, and global trade all contribute to the spread of infectious disease.

The expanded use of cell phones does not have an impact on the spread of infectious disease. Climate change, ecosystem disturbances, war, poverty, migration, and global trade all contribute to the spread of infectious disease.

The expanded use of cell phones does not have an impact on the spread of infectious disease. Climate change, ecosystem disturbances, war, poverty, migration, and global trade all contribute to the spread of infectious disease.