Disease Transmission and Infection Control Vocabulary

Vocabulary flashcards covering disease transmission, the chain of infection, infection types, standard and transmission-based precautions, PPE donning/doffing, sharps disposal, sanitization, and exposure protocols.

Chain of Infection

A 6-link process of disease transmission consisting of Pathogen, Reservoir, Portal of Exit, Mode of Transmission, Portal of Entry, and Susceptible Host.

Pathogen

An infectious agent (germs), mostly found in the form of a virus, bacteria, fungi, or protozoa.

Reservoir

The environment in which a pathogen can grow and live (where germs live), such as medical equipment or the human body.

Portal of Exit

The passageway that a pathogen uses to exit the reservoir (how germs get out), such as the nose or mouth.

Direct Transmission

A mode of transmission involving direct contact with an infected person or body fluid carrying the pathogen.

Indirect Transmission

A mode of transmission involving an intermediate step between the portal of exit and portal of entry, using vectors or fomites.

Vectors

Insects that act as intermediate transmitters of pathogens during indirect transmission.

Fomites

Inanimate objects involved in indirect transmission, such as medical equipment, keyboards, faucets, countertops, pens, phones, and clothes.

Portal of Entry

The mechanism or pathway by which a pathogen enters a host (how germs get in).

Susceptible Host

A human body (the next sick person), such as an immunocompromised individual, that is vulnerable to infection.

Inflammatory Response Symptoms

Symptoms activated during stages of infection when the body responds with histamines, kinins, and prostaglandins, characterized by erythema, edema, pain, and heat.

Acute Infection

An infection where symptoms appear suddenly and worsen quickly, with the body recovering in a few weeks (e.g., common cold, influenza).

Chronic Infection

An infection that lingers, sometimes forever, where symptoms may not last continuously but the pathogen can possibly transmit to others (e.g., Hepatitis B, COPD, chronic kidney failure).

Latent Infection

An infection characterized by alternating periods of remission and relapse (e.g., cold sores, STDs).

Opportunistic Infection

An infection occurring in a person with a weakened immune system caused by organisms that typically do not infect a healthy patient (e.g., AIDS, cancer patients).

Standard Precautions

Infection control practices (formerly universal precautions) designed to reduce healthcare-associated infections (HAI) when handling body fluids, non-intact skin, or mucous membranes.

Droplet Precautions

Infection control measures required for large pathogen droplets that travel up to $3\,\text{feet}$ (e.g., Rubella, mumps, pertussis, influenza), requiring mask/face protection when interacting with patients.

Airborne Precautions

Infection control measures for diseases spread through the air by droplets smaller than $5\,\mu\text{m}$ in diameter, requiring an N95 respirator, gown, gloves, and a negative pressure room.

Airborne Infection Isolation Room (AIIR)

A negative pressure room with restricted airflow relative to the rest of the facility, required for housing patients under airborne precautions.

Reverse Isolation

Procedures used when a patient's immune system is compromised to protect the patient from coming into contact with harmful pathogens from healthcare workers or the environment.

Contact Precautions

Infection control measures for infections spread through direct contact or contact with the environment, requiring gloves and gowns (e.g., MRSA, VRE, C-diff, scabies).

Donning PPE

The correct sequence for putting on personal protective equipment: wash hands, gown, mask, goggles, gloves.

Doffing PPE

The correct sequence for removing personal protective equipment: gloves, goggles, gown, mask, wash hands.

Bloodborne Pathogens Standard

OSHA-established regulation requiring work practices and engineering controls to prevent infectious exposure, including training, PPE, and HBV vaccine availability.

Sharps Container

A leak-proof, puncture-resistant biohazard container with a closure system used to dispose of items that can easily break skin, which must not be filled to the top.

NIOSH Criteria for Sharps Containers

Four essential criteria established by NIOSH to evaluate sharps container safety: Functionality, Accessibility, Visibility, and Accommodation.

Sanitization

The process of cleaning visibly soiled equipment to reduce the number of microbes so the instruments are prepared for sterilization or disinfection.

Disinfection

The process of destroying pathogens on a surface using chemical disinfectants (e.g., bleach, ethyl alcohol, isopropyl alcohol, ammonia chlorides), which reduces spread but does not kill all spores.

Sterilization

The process that destroys all pathogens and their spores on inanimate objects using heat, water, chemicals, or gases.

Autoclave

A sealed container or machine used for steam sterilization of equipment.

Exposure Control Plan

An annual, organization-specific plan mandated by OSHA outlining job protections, PPE, exposure action plans, hazard labeling, immunizations, record-keeping, and training.

Needlestick Injury Protocol

The protocol following a needlestick: first wash hands with soap and water or decontaminate with antiseptic (iodine), notify supervisor, complete an incident report, and obtain medical examination/post-exposure prophylaxis (HIV PEP within $2\,\text{hours}$).