Infections come from four families of pathogens: bacteria, viruses, fungi, and parasites. Each one acts in its own way, and each needs its own drug. Click each one to see what it is, how we find it, and how we fight it.
Meet the germ
A picture of each pathogen family, and how it makes us sick.
Pick a pathogen to explore.
Pick a pathogenbacteria · virus · fungus · parasite
What it is
How we test: a Gram stain sorts bacteria by their cell wall. Gram-positive means a thick wall that stains purple. Gram-negative means a thin wall plus an outer membrane. It stains pink and is harder to treat. A culture & sensitivity comes next. The culture names the bug, and the sensitivity picks the antibiotic.