Infection Control Vocabulary

Disease Conditions

• Symptoms:

  • Objective: Observable or measurable signs of disease (e.g., fever, rash). These can be directly observed or measured by a healthcare professional.

  • Subjective: Symptoms felt by the patient, like pain or nausea. These are based on personal experience and cannot be directly measured.

• Key terminology:

  • Disease: A condition with specific signs and symptoms that impairs normal functioning. Can be caused by infections, genetics, or environmental factors.

  • Etiology: The cause of a disease, which can include genetic factors, infectious agents, or environmental exposures.

  • Pathology: The study of disease, including its causes, mechanisms, and effects on the body.

  • Diagnosis: Identification of a disease through examination of symptoms, signs, and tests. It is the process of determining which disease or condition explains a person's symptoms and signs.

  • Prognosis: Prediction of the course of a disease, including the likelihood of recovery or potential complications. It is an estimation of the likely outcome of a disease.

• Types of Disease:

  • Acute: Severe and sudden onset, typically lasting a short time (e.g., common cold, influenza). Symptoms develop rapidly and are often intense.

  • Chronic: Long-term or recurring, often lasting for months or years (e.g., diabetes, arthritis). Develops slowly and can persist for a lifetime.

  • Remission: Symptoms subside, indicating a period of reduced disease activity. Can be spontaneous or induced by treatment.

• Intensity:

  • Epidemic: Affecting many persons at the same time, and spreading from person to person in a locality where the disease is not permanently prevalent. Example: A flu outbreak in a city.

  • Pandemic: An epidemic that is geographically widespread, affecting multiple countries or continents (e.g., COVID-19). Has a global reach.

  • Endemic: Present or usually prevalent in a population or geographical area at all times (e.g., malaria in certain regions of Africa). Disease is constantly present.

  • Outbreak: A sudden increase in the occurrence of a disease in a particular time and place. May be limited to a small area or a specific group of people.

• Classification:

  • Exogenous: Caused by external factors such as pathogens, chemicals, or injuries. Originates outside the body.

  • Endogenous: Arising from internal factors such as genetic defects or autoimmune reactions. Originates within the body.

  • Congenital: Present from birth, often due to genetic or developmental factors. May be inherited or caused by environmental factors during pregnancy.

  • Degenerative: Results from progressive damage to tissues or organs over time (e.g., Alzheimer's disease, osteoarthritis). Often associated with aging.

  • Opportunistic: Occurs when the body's defenses are weak, allowing normally harmless microorganisms to cause infection. Common in immunocompromised individuals.

  • Nosocomial: Originating in a hospital, typically due to infections acquired during a hospital stay. Also known as healthcare-associated infections (HAIs).

Causes of Diseases and Infection

• Bacteria:

  • Shapes: oval/spherical (cocci), rod-shaped (bacilli), spiral/curved (spirilla, vibrios). Morphology affects their behavior and identification.

  • Aerobic: Requires oxygen. They use oxygen for metabolic processes.

  • Facultative aerobes: Can grow with or without oxygen. They adapt to different oxygen levels.

  • Obligate aerobes: Requires oxygen to grow. They cannot survive without oxygen.

  • Anaerobic bacteria: Does not require oxygen.

  • Facultative anaerobes: Can grow with or without oxygen. They can switch between aerobic and anaerobic respiration.

  • Obligate anaerobes: Cannot grow when oxygen is present. Oxygen is toxic to them.

  • Flagella: Used for movement. These are appendages that enable bacteria to move.

  • Spores: Resistant structures that help bacteria survive in harsh conditions. Highly resistant to heat, radiation, and disinfectants.

• Viruses

• Pathogens: Disease-causing agents, including bacteria, viruses, fungi, and parasites. They invade the host organism and cause illness.

• Rickettsia

• Fungi

• Protozoa

• Saprophytes: Organisms that live on dead or decaying organic matter.

• Nematodes: Parasitic worms that can cause infection.

• Commensal: Living in a relationship where one organism benefits and the other is not harmed. Part of the normal flora and usually don't cause disease.

• Blood-borne: Carried in the blood; refers to pathogens that can be transmitted through blood or body fluids.

Port of Entry

• Droplet: Transmission via respiratory droplets produced by coughing or sneezing.

• Indirect: Transmission via a contaminated object or surface.

• Contact: Direct physical contact with an infected person or animal.

• Parenteral: Introduction of pathogens through the skin, such as by injection or puncture.

• Carrier: An individual who harbors and spreads a disease-causing organism but shows no symptoms.

• Vector-borne: Transmission by an insect or other animal (vector) that carries the pathogen.

• Chain of infection: The sequence of steps required for an infection to spread: infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, and susceptible host.

• Food, soil, and water: Sources of pathogens that can cause disease.

Immunity

• Types:

  • Natural: Innate immunity, present from birth and provides immediate, non-specific defense.

  • Natural acquired: From exposure to a pathogen, leading to antibody production and long-term immunity.

  • Artificial acquired: From vaccination or immunization, which stimulates the immune system to produce antibodies.

  • Passive acquired: Antibodies from another source, providing temporary protection.

  • Passive natural: Antibodies from mother to fetus via placenta or breast milk.

• Immunocompromised: Having an impaired immune system, making one more susceptible to infections.

• Virulence: Severity of disease caused by a pathogen; the degree to which a pathogen can cause disease.

• Methods to acquire immunity:

  • Antigen intake and antibody response: The body recognizes and responds to foreign substances (antigens) by producing antibodies.

  • Inoculation: Introduction of a pathogen or antigen to stimulate immunity; can be natural (exposure) or artificial (vaccination).

  • Vaccination: Injection of a weakened or inactive pathogen to produce immunity by stimulating antibody production.

  • Autogenous vaccine: Vaccine produced from an individual's own bacteria, used for chronic or recurrent infections.

  • Attenuated microbes: Weakened pathogens used in vaccines, which can stimulate an immune response without causing severe disease.

Disease Prevention

• Sanitation: Maintaining cleanliness and hygiene to prevent the spread of disease.

• Sterilization: Eliminating all forms of microbial life, including bacteria, viruses, fungi, and spores.

• Asepsis: Absence of pathogenic microorganisms; creating a sterile environment.

• Disinfection: Reducing the number of pathogenic microorganisms to a safe level.

• Universal precautions: Treating all blood and body fluids as if they are infectious.

• Infection Risk and Cleaning:

  • Critical: High risk of infection if contaminated; items that penetrate soft tissue or bone must be sterilized.

  • Invasive: Penetrating soft tissue or bone, requiring sterilization.

  • Methods: Autoclave, dry heat, and heat chemical vapor: These methods ensure complete sterilization.

  • Semicritical: Contact mucous membrane; items that contact mucous membranes require high-level disinfection.

  • High-level disinfection: Kills all microorganisms except large numbers of bacterial spores.

  • Noncritical: Contact intact skin; items that contact intact skin require hospital disinfection.

  • Hospital disinfection: Cleaning and disinfection procedures used in hospitals to reduce the risk of infection.

Sterilization & Disinfection Methods

• Sterilization: Total killing of all microbes; complete elimination of all microorganisms.

• Disinfection: Obtaining germ-free area; reducing the number of microorganisms to a safe level.

• Methods of sterilization and disinfection:

  • Autoclave: Uses high-pressure steam to sterilize items.

  • Flash autoclave: A type of autoclave that sterilizes items quickly.

  • Dry heat: Uses high temperatures to sterilize items.

  • Glass bead heat or molten metal: Used for sterilizing small instruments quickly.

  • Chemical vapor sterilization: Uses a chemical vapor to sterilize items.

  • Ethylene oxide: A gas used to sterilize heat-sensitive items.

  • VPH (vaporized hydrogen peroxide): Uses vaporized hydrogen peroxide to sterilize items.

  • Chemical agents: Liquid chemicals used for disinfection or sterilization.

  • Indicator strips: Used to verify that sterilization has occurred.

  • Cassette trays: Used to hold and organize instruments during sterilization.

  • Disinfectant: A chemical agent used to kill or inhibit the growth of microorganisms on inanimate objects.

  • Antiseptic: A chemical agent used to kill or inhibit the growth of microorganisms on living tissue.

  • Bacteriostatic: Inhibits bacterial growth without killing them.

  • Germicide: Kills germs; a broad-spectrum antimicrobial agent.

  • Holding solution: Used to prevent drying of instruments before sterilization.

  • Ultrasonic cleaner: Uses sound waves to remove debris from instruments.

Other Prevention Methods

• Disposal techniques: Proper methods for disposing of contaminated waste to prevent the spread of infection.

• Material safety data sheet (MSDS) papers: Documents that provide information on the safe handling, storage, and disposal of hazardous materials.

• Saturate-wipe-saturate disinfection: A method of disinfection that involves saturating a surface with disinfectant, wiping it, and then saturating it again.

• Personal protective equipment (PPE): Equipment worn to minimize exposure to hazards that cause serious workplace injuries and illnesses.

• Barriers: Physical barriers used to prevent the spread of infection, such as gloves, masks, and gowns.

• Standard operating procedures (SOP): Detailed written instructions to achieve uniformity of the performance of a specific function or task.

• Universal or standard precautions: Treating all blood and body fluids as if they are infectious.

Agencies Concerned with Disease Control

• Occupational Safety & Health Administration (OSHA): Ensures safe and healthful working conditions for workers by setting and enforcing standards and by providing training, outreach, education and assistance.

• Centers for Disease Control and Prevention (CDC): A national public health agency that works to protect America from health, safety and security threats.

• Food and Drug Administration (FDA): Responsible for protecting the public health by ensuring the safety, efficacy, and security of human and veterinary drugs, biological products, and medical devices.

• Environmental Protection Agency (EPA): Protects human health and the environment by writing and enforcing regulations based on laws passed by Congress.

• Organization for Safety and Asepsis Procedures (OSAP): A community of clinicians, educators, researchers, and industry representatives who advocate for safe and infection-free delivery of oral healthcare.