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Infectious Disease

Infectious diseases are caused by organisms - such as bacteria, viruses, fungi or parasites. A person may become ill with an infectious disease through contact with another infected person (directly or indirectly), an insect or animal carrying disease, or contaminated food or water.

Infectious Diseases

  • Foodborne and waterborne illnesses
  • Zoonotic diseases, which spread from animals to people
  • Vaccine-preventable diseases, including Covid-19, viral hepatitis, pertussis, and influenza
  • Sexually transmitted diseases
  • Healthcare-associated infections (HAIs), which are infections that patients get while receiving medical treatment for another condition

Why It's Important

Infectious diseases are a major cause of illness, disability, and death. For example, CDC estimates that each year roughly 1 in 6 Americans (or 48 million people) get sick, 128,000 are hospitalized, and 3,000 die of foodborne diseases. Infectious diseases are also associated with substantial health care costs. Healthcare-associated infections alone account for billions of dollars of health care costs in the United States each year.

Many infectious disease illnesses and deaths are preventable. By monitoring disease incidence and studying how and why infectious diseases spread, public health aims to stop illness from spreading and prevent diseases from occurring in the future

Who Is at Risk

Every living organism is at risk of illness from infectious diseases. Some factors that are associated with the probability of becoming ill with infectious disease include:

  • Individual health status
  • Age
  • Immunization Status
  • Community immunization status
  • Environmental Conditions
  • Region or location of residence
  • Proximity to sources of disease transmission
  • Occupation

Illness with infectious disease occurs when an individual is exposed to a disease causing pathogen by the correct mode of transmission while that individual is particularly susceptible to the pathogen.

How To Reduce Risk

To reduce the risk of illness it is important to control infectious disease by disrupting disease transmission. This can be accomplished by:
  • Vaccination: Infectious diseases that are vaccine preventable are controlled by giving immunity to vaccinated individuals. The more people that are vaccinated in a community the less likely an infectious disease is able to spread and make people ill.
  • Wearing Masks: Wearing masks helps reduce the spread of airborne infectious diseases such as Covid-19 and influenza.
  • Hand Washing: Hand washing decreases the amount of infectious diseases that we are exposed to by physically removing pathogenic organisms from our hands.
  • Food Safety and Water Quality: Following good food safety and handling practices decreases the quantity of pathogenic organisms that are ingested.
  • Stay Home When Sick: When sick stay home to prevent spreading illness to others.
  • Use Precautions: When outdoor use insect repellent and protective clothing to protect yourself from insect that may carry infectious diseases

How It's Tracked

Reportable infectious diseases in the United States are tracked by Local, State, and Federal government utilizing a cooperative relationship with clinicians and laboratorians. When an individual is identified with an infectious disease clinicians and laboratorians report to their local or state health department. All disease specific information is collected regarding the infectious disease event and is then reported to the CDC. The information collected can be used for many purposes at many different jurisdictional levels such as to:

  • Educate the public
  • Guide policy and public health decisions
  • Alert clinicians to aid in diagnosis
  • Implement public health interventions during epidemics
  • Describe infectious disease in different populations
  • Identify risk factors for disease

The information collected during the disease investigation process has all personal identifiers removed and the data is then available to the public. This de-identified public data is used by both public and private entities for research and business development, further supporting the importance of tracking infectious diseases.