Infectious Disease Basics: Pathogens, Transmission, and Prevention Save Groups

Infectious Disease

A disease caused by a pathogen that invades the body and can spread between people

Pathogen

A disease-causing agent

Bacteria

Single-celled living organisms that can cause disease

Virus

A nonliving pathogen that must use a host to reproduce

Fungi

Pathogens that can cause infections, often treated with antifungal medication

Protozoa

Single-celled organisms that can cause disease

Parasite

An organism that lives on or in a host and causes harm

Antibiotics

Medicines that kill or slow the growth of bacteria

Antibiotic Resistance

When bacteria survive and grow despite antibiotic treatment

Viral Treatment

Letting the virus run its course

Most Common Parasitic Infection in the U.S.

Head lice

Immune System

The body's defense against pathogens

Inflammatory Response

The body's reaction to injury or infection

Symptom

A change in the body or mind caused by disease

Fever

A common symptom of infection, elevated body temperature

Rash

A change in skin appearance caused by disease or allergic reaction

Headache

Pain in the head caused by infection or other conditions

Incubation Period

Time between pathogen entry and first symptoms; no symptoms yet ('silent stage')

Prodromal Stage

Stage where mild, general symptoms appear; pathogen continues to multiply

Clinical Stage (Acute Stage)

Most severe stage with clear symptoms; disease at its peak

Decline Stage

Symptoms begin to decrease; the body starts recovery

Recovery Stage

Pathogen eliminated; transmission still possible but unlikely

Chain of Infection

The process that explains how infectious diseases spread from one person to another

Agent

The disease-causing pathogen (first link in the chain)

Reservoir

The place where the pathogen lives and survives (people, animals, water, environment)

Portal of Exit

How the pathogen leaves the reservoir (digestive, urinary, respiratory, reproductive systems, blood)

Mode of Transmission

How the pathogen spreads from the reservoir to a new host

Direct Transmission

Person-to-person spread through contact, droplets, or fecal-oral routes

Indirect Transmission

Spread through objects, food, water, air, or vectors

Vector

A living organism (such as insects or animals) that carries pathogens

Portal of Entry

How the pathogen enters a new host (digestive, respiratory, reproductive systems)

New Host

The person who becomes infected (final link in the chain)

Difference Between Bacteria and Viruses

Bacteria are single-celled organisms; viruses are not living and need a host to reproduce

Ways Diseases Are Spread

Person-to-person, food and water, environment, animals

Ways to Protect Yourself

Vaccination, do not share personal items, maintain hygiene, be cautious in public

Treatment of Fungal Infections

Mild: over-the-counter medication; Severe: stronger prescription medication

Protection from Protozoan Infections

Maintain good hygiene and sanitation