Infectious Diseases

Summary

Germs, or microbes, are found everywhere – in the air, soil, and water. There are also germs on your skin and in your body. Many of them are harmless, and some can even be helpful. But some of them can make you sick. Infectious diseases are diseases that are caused by germs.

There are many different ways that you can get an infectious disease:

• Through direct contact with a person who is sick. This includes kissing, touching, sneezing, coughing, and sexual contact. Pregnant mothers can also pass some germs along to their babies.
• Through indirect contact, when you touch something that has germs on it. For example, you could get germs if someone who is sick touched a door handle, and then you touch it.
• Through insect or animal bites
• Through contaminated food, water, soil, or plants

There are four main kinds of germs:

• Bacteria – one-celled germs that multiply quickly. They may give off toxins, which are harmful chemicals that can make you sick. Strep throat and urinary tract infections are common bacterial infections.
• Viruses – tiny capsules that contain genetic material. They invade your cells so that they can multiply. This can kill, damage, or change the cells and make you sick. Viral infections include HIV/AIDS and the common cold.
• Fungi – primitive plant-like organisms such as mushrooms, mold, mildew, and yeasts. Athlete’s foot is a common fungal infection.
• Parasites – animals or plants that survive by living on or in other living things. Malaria is an infection caused by a parasite.

Infectious diseases can cause many different symptoms. Some are so mild that you may not even notice any symptoms, while others can be life-threatening. There are treatments for some infectious diseases, but for others, such as some viruses, you can only treat your symptoms. You can take steps to prevent many infectious diseases:

• Get vaccinated
• Wash your hands often
• Pay attention to food safety
• Avoid contact with wild animals
• Practice safe sex
• Don’t share items such as toothbrushes, combs, and straws

National Institute of Allergy and Infectious Diseases

Related Issues

• Antibiotic Resistance: MedlinePlus Health Topic National Library of Medicine
• Bacterial vs. Viral Infections: How Do They Differ? Mayo Foundation for Medical Education and Research
• Quarantine and Isolation Centers for Disease Control and Prevention
• What’s the Difference Between Infectious and Contagious? Nemours Foundation

Find an Expert

• Centers for Disease Control and Prevention Centers for Disease Control and Prevention
• National Foundation for Infectious Diseases National Foundation for Infectious Diseases
• National Institute of Allergy and Infectious Diseases National Institute of Allergy and Infectious Diseases

Children

• Childhood Contagious Diseases VisualDX
• Overview of Infectious Diseases American Academy of Pediatrics
• Repeated Infections in Children American Academy of Family Physicians

Clinical Trials

• ClinicalTrials.gov: Communicable Diseases National Institutes of Health

Living With

• Coping with Stress during Infectious Disease Outbreaks Substance Abuse and Mental Health Services Administration
• Taking Care of Your Behavioral Health: Tips for Social Distancing, Quarantine, and Isolation during an Infectious Disease Outbreak Substance Abuse and Mental Health Services Administration

Encyclopedia

• CSF cell count Medical Encyclopedia
• Latex agglutination test Medical Encyclopedia

Statistics and Research

• FastStats: Infectious Disease National Center for Health Statistics

Specifics

• From A to Zika: Understanding Emerging Diseases National Institutes of Health
• Recurrent Infections May Signal Immunodeficiencies American Academy of Allergy, Asthma, and Immunology
• Types of Neglected Tropical Diseases National Institute of Allergy and Infectious Diseases

Prevention and Risk Factors

• Germs and Hygiene: MedlinePlus Health Topic National Library of Medicine

Start Here

• Germs: Understand and Protect against Bacteria, Viruses, and Infections Mayo Foundation for Medical Education and Research
• Infectious Diseases Mayo Foundation for Medical Education and Research

Diagnosis and Tests

• PCR Tests National Library of Medicine
• Rapid Tests National Library of Medicine

Journal Articles

• Infectious Diseases