A pathogen is any organism or agent that cause disease in another living thing (its host). Your body contains trillions of good bacteria that help with digestion and immunity, but pathogens are biological invaders that disrupt your systems and make you sick.
They are referred to as germs, that spread through various ways, such as touch, contaminated food/water, or droplets in air.
Types of Pathogens and Examples
Pathogens are generally categorized by their biological structure. Here are four primary types:
1. Bacteria
Bacteria are single-celled microorganisms. While most are harmless or even helpful, some pathogenic bacteria cause disease by releasing toxins or damaging tissues.
-
Streptococcus: Causes strep throat and scarlet fever.
-
Salmonella: Often found in undercooked poultry, causing food poisoning.
-
Mycobacterium tuberculosis: bacterium responsible for tuberculosis (TB).
2. Viruses
Viruses are much smaller than bacteria and aren’t technically alive because they cannot reproduce on their own. They use host cells to create more copies of themselves.
-
-
Influenza: virus that causes the seasonal flu.
-
SARS-CoV-2: virus responsible for COVID-19.
-
Rhinovirus: virus behind common cold.
-
3. Fungi
Fungi include yeasts, molds, and mushrooms. Pathogenic fungi usually cause skin infections or respiratory issues, especially in people with weakened immune systems.
-
Tinea pedis: Fungus that causes Athlete’s Foot.
-
Candida albicans: Causes thrush and yeast infections.
-
Histoplasma: A fungus found in soil that can cause lung infections if inhaled.
4. Parasites
Parasites are organisms that live in or on a host and feed at host’s nutrients. They range from microscopic single-celled organisms to visible worms.
-
Plasmodium: The protozoa transmitted by mosquitoes that causes Malaria.
-
Giardia: A microscopic parasite found in contaminated water that causes diarrhea.
-
Tapeworms: Intestinal parasites that can grow several feet long inside the digestive tract.
How Pathogens Spread
Understanding how they spread is the best way to prevent infection:
-
Direct Contact: Skin-to-skin contact or kissing.
-
Indirect Contact: Touching a contaminated surface (like a doorknob).
-
Airborne: Inhaling droplets from a sneeze or cough.
-
Vector-borne: Transmitted via insects like mosquitoes or ticks.