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

Antibiotics only work on bacterial infections, not viral infections such as influenza and the common cold. In fact, inappropriate use and overuse of antibiotics contributes to the emergence of drug-resistant bacteria. 

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.

The mosquito is the vector for West Nile virus. The mosquito suffers no ill effects from the virus but transmits it to humans and other warm-blooded creatures (such as crows) when it takes a blood meal. 

The mosquito is the vector for West Nile virus. The mosquito suffers no ill effects from the virus but transmits it to humans and other warm-blooded creatures (such as crows) when it takes a blood meal. 

The mosquito is the vector for West Nile virus. The mosquito suffers no ill effects from the virus but transmits it to humans and other warm-blooded creatures (such as crows) when it takes a blood meal. 

In syndromic surveillance, all of the above are used in addition to other patterns that suggest an outbreak. Despite the emergence of this innovative surveillance method, most surveillance still depends on tracking reported infections. 

In syndromic surveillance, all of the above are used in addition to other patterns that suggest an outbreak. Despite the emergence of this innovative surveillance method, most surveillance still depends on tracking reported infections. 

In syndromic surveillance, all of the above are used in addition to other patterns that suggest an outbreak. Despite the emergence of this innovative surveillance method, most surveillance still depends on tracking reported infections. 

The 1918 influenza pandemic is estimated to have killed between 50 million and 100 million people worldwide. Many of those deaths were due to the effects of pneumococcal pneumonia, a secondary complication of flu for which no antibiotics existed in 1918.

The 1918 influenza pandemic is estimated to have killed between 50 million and 100 million people worldwide. Many of those deaths were due to the effects of pneumococcal pneumonia, a secondary complication of flu for which no antibiotics existed in 1918.

Life-saving vaccines and medications aren’t distributed equitably around the world; for each child who dies from pneumonia in an industrialized country, more than 2,000 children die from the infection in developing countries.

Life-saving vaccines and medications aren’t distributed equitably around the world; for each child who dies from pneumonia in an industrialized country, more than 2,000 children die from the infection in developing countries.

Life-saving vaccines and medications aren’t distributed equitably around the world; for each child who dies from pneumonia in an industrialized country, more than 2,000 children die from the infection in developing countries.

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.   

Viruses reproduce the fastest. Humans produce a new generation every 20 years or so; bacteria do it every 20 to 30 minutes, and viruses even faster.

Viruses reproduce the fastest. Humans produce a new generation every 20 years or so; bacteria do it every 20 to 30 minutes, and viruses even faster.