Agents of Infection SC.6.L.14.6 Compare and contrast types of infectious agents that may infect the human body, including viruses, bacteria, fungi, and parasites.

What is disease? Different diseases have a specific set of symptoms, or changes in how a person with an illness feels. All diseases are categorized as noninfectious or infectious diseases.

What is noninfectious disease? Noninfectious diseases cannot be spread from person to person. Hereditary factors can cause noninfectious diseases. Environmental factors can cause noninfectious disease. Mutagens are substances that cause mutations, or changes, in DNA that may result in disease. Cancer is a group of noninfectious diseases caused by both hereditary and environmental factors.

What is infectious disease? A disease that is caused by a pathogen is called an infectious disease. Living pathogens include bacteria, fungi, and parasites. Viruses are pathogens that are non-cellular. They cannot function on their own. Infectious diseases can be passed from person to person. Pathogens can be passed from nonliving objects and from other living things.

What can cause infectious disease? Viruses are tiny particles that have their own genetic material and depend on living things to reproduce. Influenza, the common cold, and HIV are examples of diseases caused by viruses.

What causes infectious disease? Many bacteria are beneficial to living things, but some cause disease. Tuberculosis, strep throat, diarrheal illness, and some sinus infections are caused by bacteria.

What causes infectious disease? Most fungi are beneficial because they break down dead plants and animals. Some fungi are pathogens. Athlete’s foot and ringworm are two common skin infections caused by fungi.

What causes infectious disease? A parasite is an organism that feeds on another organism, called a host. Parasites harm their hosts. Malaria, giardiasis, and worm infections are common parasitic infections.

How can infectious diseases be transmitted? Contagious diseases can be spread easily from person to person or from other organisms to people. Water and food supplies can be contaminated and cause sickness. Diseases can be spread through the air, through touching an infected person, and through sexual contact.

How can infectious diseases be transmitted? Insects, ticks, and other animals can spread disease. Objects that are handled by sick people or that come in contact with infected animals or contaminated food can pick up pathogens. Contaminated needles can transmit diseases.

How can diseases be reduced? Improved personal hygiene and improved technology have helped reduce the spread of disease. Vaccines prevent serious illnesses worldwide. Food preservation techniques help reduce contamination of foods with pathogens.

How can diseases be reduced? Some bacteria have developed a resistance to antibiotics. Washing your hands throughout the day can reduce the risk for some infections.

How can disease be treated? Antibiotics are medicines used to kill or slow the growth of bacteria and other microorganisms, such as fungi. Antibiotics do not work on viruses. Antiviral drugs are drugs that destroy viruses or prevent their replication.