Germs: Understand and protect against bacteria, viruses and infections
Mar 5, 2024 · Infection, often the first step in getting a disease, occurs when bacteria, viruses or other microbes that cause disease enter the body and begin to multiply. Disease happens when the …
Bacterial vs. viral infections: How do they differ? - Mayo Clinic
Nov 25, 2025 · Bacteria cause bacterial infections. Viruses cause viral infections. Antibiotic medicines kill or keep many bacteria from growing but don't treat viruses. Antiviral medicines help the body …
Medical Diseases & Conditions - Mayo Clinic
Explore comprehensive guides on hundreds of common and rare diseases and conditions from the experts at Mayo Clinic.
Infectious diseases - Symptoms & causes - Mayo Clinic
Apr 8, 2025 · Viruses. These microscopic germs are even smaller than bacteria. They cause many diseases, including the common cold, COVID-19 and HIV. Fungi. These cause many skin diseases, …
Infectious diseases - Diagnosis & treatment - Mayo Clinic
Apr 8, 2025 · Some types of bacteria are especially prone to certain classes of antibiotics. Treatment can be targeted more precisely if your healthcare team knows what type of bacteria you're infected with.
Influenza (flu) - Symptoms and causes - Mayo Clinic
Dec 19, 2025 · Influenza viruses are constantly changing, with new strains appearing often. A person's first flu infection gives some long-term protection against similar strains of flu. But the vaccines …
Gene therapy - Mayo Clinic
Apr 23, 2024 · Viruses aren't the only vectors that can be used to carry changed genes into your body's cells. Other vectors being studied in clinical trials include: Stem cells. All cells in your body are …
Influenza (flu) - Diagnosis and treatment - Mayo Clinic
Dec 19, 2025 · Diagnosis Flu vaccines at Mayo Clinic Mayo Clinic offers flu shots in Arizona, Florida and Minnesota. Learn more about how to get your flu shot at Mayo Clinic. To diagnose the flu, also called …
Sexually transmitted diseases (STDs) - Symptoms and causes
Viruses. STDs caused by viruses include human papillomavirus (HPV), the herpes simplex virus, and the human immunodeficiency virus (HIV), which causes AIDS. Risk factors Anyone who is sexually …
Types of infectious agents - Mayo Clinic
Infectious agents come in many shapes and sizes. Bacteria and protozoans are microscopic one-celled organisms. Viruses are even smaller. Fungi grow like plants. Helminths resemble worms.