Germs: Understand and protect against bacteria, viruses and infections
Mar 5, 2024 · Viruses are responsible for causing many diseases, including: Common cold. Influenza. Measles. Chickenpox and shingles. Coronavirus disease 2019, also called COVID-19. Antibiotics kill …
Bacterial vs. viral infections: How do they differ? - Mayo Clinic
Nov 25, 2025 · Viruses that become resistant to antivirals have affected treatment, including for genital herpes, HIV and, in 2008, for influenza (flu). Treating and preventing bacterial and viral infections In …
Infectious diseases - Symptoms & causes - Mayo Clinic
Apr 8, 2025 · Bacteria, viruses, fungi and parasites are examples of organisms that can cause illness. Many organisms live in and on our bodies. They're too small to see with the eyes. And they're often …
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 …
Medical Diseases & Conditions - Mayo Clinic
Explore comprehensive guides on hundreds of common and rare diseases and conditions from the experts at Mayo Clinic.
Diarrhea - Symptoms and causes - Mayo Clinic
Jan 18, 2025 · Causes A number of diseases and conditions can cause diarrhea, including: Viruses. Viruses that can cause diarrhea include Norwalk virus, also known as norovirus, enteric …
COVID-19 vs. flu: Similarities and differences - Mayo Clinic
Oct 21, 2025 · Find out the similarities and differences between coronavirus disease 2019 (COVID-19) and the flu (influenza) and learn about ways to prevent getting these diseases.
Bell's palsy - Symptoms and causes - Mayo Clinic
Mar 15, 2024 · Viruses that have been linked to Bell's palsy include viruses that cause: Cold sores and genital herpes, also known as herpes simplex. Chickenpox and shingles, also known as herpes …
Coronavirus disease 2019 (COVID-19) - Symptoms and causes
Mar 13, 2026 · Coronavirus disease 2019 (COVID-19) is an illness caused by the virus SARS-CoV-2. Learn more about the symptoms, risks and ways to protect yourself.
COVID-19, cold, allergies and the flu: What are the differences?
Oct 22, 2025 · The flu is caused by influenza A, B and C viruses. All of these viruses spread in similar ways. COVID-19 and the flu cause many of the same symptoms, but there are some differences. …