By identifying pathogens in the animals where they naturally live and monitoring those organisms as they move from animals into people, it may be possible to prevent deadly new infections of animal origin from entering and racing through human populations.

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. 

All of the above are urgently needed in developing nations. A major barrier to achieving these improvements is the underlying weakness of health systems in resource-poor countries, including a shortage of health workers and a lack of disease surveillance programs.

All of the above are urgently needed in developing nations. A major barrier to achieving these improvements is the underlying weakness of health systems in resource-poor countries, including a shortage of health workers and a lack of disease surveillance programs.

All of the above are urgently needed in developing nations. A major barrier to achieving these improvements is the underlying weakness of health systems in resource-poor countries, including a shortage of health workers and a lack of disease surveillance programs.

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.

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.

An estimated 1.8 million airline passengers cross international borders daily, creating routes by which human infections can radiate around the world within hours.

An estimated 1.8 million airline passengers cross international borders daily, creating routes by which human infections can radiate around the world within hours.

Influenza is not a vector-borne disease, meaning it is not transmitted to humans indirectly via an insect, an arthropod, or another animal. Malaria and yellow fever are transmitted by mosquitoes. Lyme disease is transmitted by deer ticks.

Influenza is not a vector-borne disease, meaning it is not transmitted to humans indirectly via an insect, an arthropod, or another animal. Malaria and yellow fever are transmitted by mosquitoes. Lyme disease is transmitted by deer ticks.

Influenza is not a vector-borne disease, meaning it is not transmitted to humans indirectly via an insect, an arthropod, or another animal. Malaria and yellow fever are transmitted by mosquitoes. Lyme disease is transmitted by deer ticks.

“Antibiotic resistance” refers to the ability of bacteria to resist the effects of an antibiotic. Antibiotic resistance occurs when bacteria undergo a genetic change that reduces or eliminates the effectiveness of drugs or other agents designed to cure or prevent infection.

“Antibiotic resistance” refers to the ability of bacteria to resist the effects of an antibiotic. Antibiotic resistance occurs when bacteria undergo a genetic change that reduces or eliminates the effectiveness of drugs or other agents designed to cure or prevent infection.

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.