Contact Transmission: A-to-Z Guide

Two happy cute little girls playing with blocks. Contact transmission can happen through play.

Introduction to contact transmission:

Sometimes a touch can bring more than you expect—from head lice to herpes to impetigo. Understanding how diseases can spread makes them easier to prevent.

What is contact transmission?

Contact transmission requires some form of touch to spread an infection. Direct contact transmission involves immediate contact between two people (or with an animal). Indirect contact transmission involves fomites; an object that becomes contaminated by touch (the fomite) then spreads the infection by touch.

Conjunctivitis, or “pink eye,” is commonly spread by touch. Other examples include Respiratory syncytial virus (RSV) , shingles, and Ebola.

Most germs have to enter the mouth, nose, or eye to cause an infection, but there are several that can spread directly from skin to skin. Skin-to-skin transmission occurs when bacteria, viruses, or parasites found on the skin of one child (or animal) are “caught” by another child through touch.

Intact skin is a powerful, protective barrier. Bacterial infections, such as the staph or strep that cause the rash of impetigo, usually spread only if there is a break in the skin, perhaps from an insect bite, a scratch, or repeatedly wiping the irritated skin under an ongoing runny nose. The same tends to be true for viral infections, such as herpes simplex.

Superficial fungal or yeast infections might spread in the absence of a break in the skin—especially where the skin is warm, moist, and dark (like the diaper area).

Parasites such as scabies or lice travel from child to child with ease. Sometimes they stop on a hairbrush or hat along the way.

Some infections can spread by contact transmission in at least some cases, including:

How can contact transmission be prevented?

Specific prevention measures are described in the articles about some of the individual conditions spread by contact transmission. When practical, avoiding direct contact with infected children is the general key—especially when there is a break in the skin. In addition, hand cleansing and surface disinfecting can interrupt some disease transmission. Also, it is generally wise for children to avoid sharing hairbrushes, combs, and hats.

Dr. Alan Greene

As a father of four himself, Dr. Greene has devoted himself to freely giving real answers to parents' real questions -- from questions about those all too common childhood conditions to those that address the most recent and rare pediatric illnesses. His answers combine cutting edge science, practical wisdom, warm empathy, and a deep respect for parents, children, and the environment. He is also an electrifying public speaker, and has personally touched many during his talks in North America, Europe, Asia, and the Middle East.

Dr. Greene is a graduate of Princeton University and the University of California at San Francisco. Upon completion of his pediatric residency program at Children's Hospital Medical Center of Northern California he served as Chief Resident. He entered primary care pediatrics in January 1993.

Dr. Greene is the Past President of The Organic Center and on the Board of Directors of Healthy Child Healthy World. He is a founding partner of the Collaborative on Health and the Environment. He also consults for the Environmental Working Group.

In 1995, he launched, cited by the AMA as “the pioneer physician Web site” on the Internet. His award-winning site has received over 80 million Unique Users from parents, concerned family members, students, and healthcare professionals. In addition to being the founder of, he is the Medical Director for HealthTap.

In 2010 Dr. Greene founded the WhiteOut Movement to change how babies in the United States are fed. In 2012 he founded TICC TOCC - Transitioning Immediate Cord Clamping To Optimal Cord Clamping. He is also the founder of KidGlyphs, a free iPhone app that provides a tool for young children to express themselves beyond their verbal skills while teaching them important language skills.

Dr. Greene is the Founding President of the Society for Participatory Medicine and has served as both President and Board Chair of Hi-Ethics (Health Internet Ethics. He is on the Board of Directors for Healthy Child Healthy World, The Lunchbox Project, and The Society for Participatory Medicine. He has also served as an advisor to URAC for both their inaugural and their updated health web site accreditation program. He is a founding member of the e-Patient Scholars Working Group, and a founding board member of the Center for Information Therapy.

Dr. Greene is a regular columnist for Parenting Magazine. He is also the Pediatric Expert for The People’s Pharmacy (as heard on NPR) and Healing Quest (seen on PBS stations). He was the original Pediatric Expert for both Yahoo! and iVillage.

Dr. Greene is the author of Feeding Baby Green (Wiley, 2009), Raising Baby Green (Wiley, 2007), From First Kicks to First Steps (McGraw-Hill, 2004), The Parent's Complete Guide to Ear Infections (People's Medical Society, 1997), and a co-author of The A.D.A.M. Illustrated Family Health Guide (A.D.A.M., Inc., 2004). He is the medical expert for three additional books, The Parent's Soup A-to-Z Guide to Your New Baby, (Contemporary Books, 1998) The Parent's Soup A-to-Z Guide to Your Toddler, (Contemporary Books, 1999), and The Mother of All Baby Books, (Hungry Minds, Inc., 2002).

Dr. Greene is a frequent keynote speaker at important events such as Health 2.0 2011 held in San Diego, CA, IFOAM 2008 (International Federation of Organic Agriculture Movements), held in Modena Italy, the first European Internet health conference, held in Maastricht, the first International eHealth Association Conference, held in Jeddah, and the largest e-Healthcare World Conference, held in Las Vegas, and the first Green Power Baby Shower, held in Hollywood. Dr. Greene also appears frequently on TV, radio, websites, and in newspapers and magazines around the world, including such venues as the TODAY Show, Good Morning America, Fox and Friends, The Dr. Oz Show, CNN, ABC, CBS, and NBC network news, NPR, The New York Times, The Wall Street Journal, USA Today, Time Magazine, Parade, Parenting, Child, Baby Talk, Working Mother, Better Home's & Gardens, and the Reader's Digest.

Dr. Greene loves to think about challenging ideas, he enjoys being where nothing manmade can be seen, and he wears green socks.

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