Overview
Infections are caused by germs such as viruses, bacteria, fungi, and parasites. These germs can spread through the air, close contact, contaminated food or water, insect bites, blood, or contact with surfaces and then the eyes, nose, or mouth. Infection prevention includes personal habits, public health measures, and steps taken in homes, schools, workplaces, and healthcare settings.
Causes and Risk Factors
Risk depends on the type of germ, how it spreads, and how much exposure occurs. Crowded indoor spaces, poor ventilation, unsafe water, inadequate sanitation, close contact with someone who is sick, unprotected sexual contact, and handling raw food without proper hygiene can increase risk. A weakened immune system, chronic illness, recent surgery, or not being up to date on recommended vaccines can also raise the chance of infection.
Who Is Affected
Anyone can get an infection, but the effects are not the same for everyone. Babies, pregnant people, older adults, and people with conditions that affect the immune system may be more likely to become seriously ill. People who travel, live in crowded settings, work in healthcare, or have limited access to clean water and sanitation may also face higher exposure risk.
Prevention
Wash hands with soap and water, especially after using the toilet, before preparing or eating food, after coughing or sneezing, and after caring for someone who is ill. Keep recommended vaccines up to date, cover coughs and sneezes, improve indoor airflow when possible, and clean high-touch surfaces when someone is sick. Use safer food and water practices, practice safer sex, avoid sharing needles or personal items that may have blood on them, and follow bite prevention advice in areas with mosquitoes or ticks.
Diagnosis and Tests
Infection prevention itself is not diagnosed, but healthcare professionals may assess infection risk based on symptoms, exposures, travel, vaccination history, and underlying health conditions. If an infection is suspected, testing may include swabs, blood tests, urine tests, stool tests, or imaging, depending on the illness. Public health guidance may also recommend testing after certain exposures or during outbreaks.
Treatment Categories
When infections occur, treatment depends on the cause and may include supportive care and, in some cases, medicines targeted to the germ type. Preventive care can also include vaccines given before exposure and specific measures after some exposures, as advised by a healthcare professional or public health authority. Not every infection needs the same treatment, and antibiotics do not treat viral illnesses such as colds or flu.
Living With It
Preventing infection often becomes part of daily routine at home, work, school, and during travel. It can help to keep hygiene supplies available, know local vaccine and outbreak guidance, and make a plan for what to do if someone in the household becomes sick. Communities also play a role through clean water systems, sanitation, food safety, and access to healthcare.
Diet and Lifestyle
General health habits support the body's ability to respond to illness, including regular sleep, physical activity, and a balanced diet. Food safety matters: wash produce when appropriate, separate raw and cooked foods, cook foods thoroughly, and refrigerate perishable items promptly. Drink water from a reliable source, and take extra care with food and water when traveling.
When to Seek Medical Care
Seek medical care if you have signs of infection that are severe, worsening, or not improving, or if you have been exposed to a serious contagious illness. Contact a healthcare professional sooner if you are pregnant, immunocompromised, very young, older, or have chronic medical conditions. It is also important to seek advice after animal bites, needle exposures, certain sexual exposures, or travel-related illness.
When It May Be an Emergency
Emergency care may be needed for trouble breathing, chest pain, confusion, seizures, blue lips, severe dehydration, or a rapidly spreading rash with fever. Get urgent help for signs of sepsis such as extreme weakness, severe shortness of breath, mottled or pale skin, or difficulty staying awake. Infants with fever, people with severe allergic reactions after a vaccine or medicine, and anyone who appears critically ill need prompt medical attention.