Infectious Diseases and Pathogens Overview

Infectious Diseases

• Pathogens are found almost everywhere.
• Bacteria and viruses are two common types of pathogens.
• Most deaths from infectious diseases are caused by a small number of diseases.
• The immune system helps to protect against pathogens.
• Epidemics are disease outbreaks affecting many people in a community or region at the same time.
• Endogenous microorganisms are normally found in the human body and are usually harmless.
• Exogenous microorganisms are not normally found in the human body and can produce infection/illness.

Types of Pathogens

Bacteria

• Bacteria are single-celled organisms.
• Bacteria are visible under a light microscope.
• Only about 100 types of bacteria cause diseases in humans.
• Some bacteria produce toxins.
• Bacteria can be treated with antibiotics.

Viruses

• Viruses cannot exist outside of a cell.
• Viruses are visible under an electron microscope.
• Over 150 types of viruses cause diseases in humans.
• Viruses are difficult to treat.

Common Pathogens

Bacteria

• Staphylococcal infections
• Streptococcal infections
• Pneumonia
• Tuberculosis

Viruses

• Common cold
• Flu
• Mononucleosis
• Measles
• Mumps
• Chicken pox
• COVID-19

Staphylococcal Infections

• Cause: Staphylococcus bacteria (endogenous).
• Transmission: broken skin.
• Symptoms: Acne, boils, styes, infected cuts, toxic shock syndrome (TSS), high fever, headache, vomiting, diarrhea, chills, rapid pulse.
• Treatment: antibiotics.

Streptococcal Infections

• Cause: Streptococcus bacteria.
• Transmission: Direct and indirect contact, airborne.
• Symptoms: Strep throat, scarlet fever (acute fever, sore throat, rash), rheumatic fever (inflammation of joints, heart, nervous system).
• Treatment: antibiotics.

Pneumonia

• Cause: Streptococcus pneumoniae bacteria.
• Transmission: Indirect contact, airborne, hospital stays, long-term care homes.
• Symptoms: Chronic cough, chest pain, chills, high fever, fluid accumulation in lungs.
• Treatment: antibiotics.

Tuberculosis

• Cause: Mycobacterium tuberculosis bacteria.
• Transmission: airborne.
• Symptoms: Persistent coughing, weight loss, fever, coughing up blood, often contagious without symptoms.
• Treatment: antibiotics.

Common Cold

• Cause: Rhinoviruses.
• Transmission: Direct and indirect contact, airborne.
• Symptoms: Sneezing, stuffy/runny nose, sore throat.
• Treatment: Bed rest, fluids, pain relievers, OTC drugs for symptom relief.

The Flu

• Cause: Influenza A or B viruses.
• Transmission: Direct and indirect contact, airborne.
• Symptoms: Fever, aches and pains, nausea, diarrhea.
• Treatment: Bed rest, fluids.
• Prevention: Flu vaccine.

Is it a Cold or the Flu?

• Differences noted in symptom onset, fever, aches, chills, fatigue, sneezing, stuffy nose, sore throat, chest discomfort/cough, headache.

Mononucleosis

• Cause: Epstein-Barr virus.
• Transmission: Direct and indirect contact, airborne.
• Symptoms: Sore throat, fever, headache, swollen lymph nodes/tonsils, weakness, fatigue.
• Treatment: Bed rest, fluids.

Measles

• Cause: Measles virus; Rubella is a milder form.
• Transmission: Indirect, airborne.
• Symptoms: Itchy rash, fever, dry cough, sore throat, appear 2 weeks after exposure.
• Treatment: Fluids, OTC pain relievers.
• Prevention: Vaccine (2 doses).

Mumps

• Cause: Mumps virus.
• Transmission: Direct and indirect contact, airborne.
• Symptoms: Swelling of salivary glands, pain while chewing/swallowing, fever, headache, weakness, fatigue. May cause sterility in men.
• Treatment: Rest, OTC pain relievers.
• Prevention: Vaccine (2 doses).

Chicken Pox

• Cause: Varicella-zoster virus.
• Transmission: Direct contact, airborne.
• Symptoms: Skin eruptions, itching, blisters, fluid-filled blisters, fever. Shingles is reactivated virus, more serious in adults.
• Treatment: Stay at home, follow health guidelines, fluids.
• Prevention: Vaccine.

COVID-19

• Cause: Human coronavirus.
• Transmission: Direct and indirect contact, airborne.
• Symptoms: New/worse cough, shortness of breath, fever, chills, fatigue, new loss of smell/taste, headache.
• Treatment: Quarantine at home. May require hospitalization.
• Prevention: Vaccine, physical distancing (2 meters), and wearing a non-medical mask.