Infections, Germs, Antibiotics, & Contagion|
"Its only a virus." "But is it catchy, doc?")
Infections are the most
widespread kind of illness in childhood. An infection is when a germ decides to live
on or in a persons body, and causes problems or symptoms as a result. Many
germs can live on or in our bodies naturally, without causing problems or symptoms.
Thats not infection, its called colonization, and its often
normal. Some germs are never harmful, so when they are found its always
considered colonization. Other germs always cause illness, and so finding them on a
person invariably means infection. Still other germs can either colonize or infect,
depending on the time, place, and situation. These can sometimes be the hardest ones
to figure out.
A germ is a small living
thing, too small to see without a microscope. There are many, many different kinds
of germs. They are divided into several broad "families": viruses,
bacteria, fungi, and protozoa. While the members of each family have many general
characteristics in common, they do differ in the specific kinds of infections they
cause. Families, however, differ from each other much more drastically. A
bacteria is as different from a fungus as an animal is from a plant. A virus is as
different from a bacteria as an insect is from a mammal (or, perhaps more accurately, as a
plankton is from a whale). Millions of viruses could fit inside a single protozoa.
Antibiotics are drugs which kill (or at least stop the growth of)
germs. Antibiotic science is by far the most advanced in the realm of anti-bacterial
medications. Most of the antibiotics we have available for use today work against
bacteria, and most known bacteria are susceptible to at least some of our antibiotics.
Fungi and protozoa can be harder to treat. While we do have some antibiotics which
work against them, they tend to be more resistant to the action of these drugs.
Anti-viral science is still in its infancy. We only have a few anti-viral
medications available today, and they only work against a very few specific types of
infection. Most viruses are impervious to all drugs known to man.
Luckily, most viral
infections are also pretty benign. Of course there are infamous exceptions (such as HIV),
but when your doctor or nurse practitioner says, "Its only a virus," what
we mean is that it is an illness which requires no treatment because it will run its
course and go away by itself, usually without damage or complications. In contrast,
its a good thing we have anti-bacterial antibiotics, and we usually will use them if
we suspect such an infection, because bacterial infections (while less common than
viruses) tend to be more dangerous and less apt to spontaneously resolve.
No drug is perfect, and
this is certainly true of antibiotics. Not only do they have risks and side effects,
but they also dont always work. When we choose which antibiotic to prescribe,
we base that judgment on the likelihood of an illness being caused by a particular germ,
and the odds of that germ being sensitive to the antibiotic. Some germs
"learn" how to resist antibiotics that they would usually be
susceptible to. Most clinical illnesses can be caused more than one germ (for
instance, there are at least 6 separate bacteria that sometimes cause ear infections).
Thus, it is usually impossible to find a single antibiotic that kills all the germs
that could possibly be causing a particular illness. If we can manage to "cover"
80-90% of the possibilities, were doing pretty well.
contagious?" Thats got to be the most frequent question a pediatrician hears. ALL infections are contagious!!! Some spread more easily than others, and by differing
routes, but thats not really what matters.
People who focus on person-to-person
spread miss the point. Germs move through entire populations. Contagion is a community
based phenomenon. The human race is to a germ as the ocean is to algae, or as the forests
are to gypsy moths. There are two major PATTERNS by which germs move through populations:
endemic and epidemic.
Endemic is the less common. An endemic illness exists at a certain
low, possibly somewhat fluctuating but basically steady rate in a community.
sporadically and semi-randomly. Person-to-person spread is important in endemic illness,
as quarantine of a case might actually affect the odds of other cases occurring nearby.
The two most common endemic childhood illnesses in the United States today are Chicken Pox
and Strep. Most common childhood infections spread by the epidemic route, however.
epidemic is like a wave moving through a community or region. It touches everybody in
its path, and knocks over all who arent strong enough to stand up to it.
a particular germ is epidemic, it literally blankets the area. Its everywhere, on
every doorknob, in every store, at every school. You cant avoid being exposed to it.
In this situation, thinking that keeping one child away from another will affect
anybodys odds of coming down with the illness is simply naïve.
illnesses include the common cold, most types of diarrhea & vomiting, most viral
rashes and coughs, and most non-Strep sore throats.
contagious, but that doesnt necessarily mean isolating a child with an infection is
a useful or logical thing to do. What else can be done? HANDWASHING.
Hands are the
dirtiest part of the human body, and most germs travel on them more often than by any
other route. It has been shown time and time again that of all the "infection
control" measures practiced in hospital settings, this is the one that has by far the
biggest impact on infection rates. Its better than masks, gowns, and isolation rooms
put together. Use soap and warm water, and wash frequently. Wash before and after contact
with someone whos sick. Have the ill child wash before going out, eating, playing
with siblings, watching the TV, and after going to the bathroom. Wash on return home from
anywhere. The more often the better. The more you wash, the less chance you give germs to
It is important to remember
its the germ, not the disease, which is contagious. Often the same germ can cause
several diseases, and the same disease can be caused by different germs. For example, the
same germ that is causing a pneumonia in one person might only cause an ear infection in
the next. This is a matter of where in the body the germ "settles", and
thats a matter of luck, not contagion.
In general, we dont
know how long things are contagious for, even when treated with antibiotics!
The truth is
that no good scientific studies have ever been done to address this question.
Physicians over the years have developed "traditional", somewhat common
sense answers such as, "until youve been on the medicine 24 hours", or,
"until the fevers gone", or, "until youre feeling better".
None of these have been proven for most infections. We do know in a few isolated
we know for Chicken Pox, for instance, that its until all the
lesions dry up. We know that for "Fifth Disease", by the time the rash comes,
the contagious phase is over. These tidbits of certainty are the exception, not the rule,
While its important
to treat with antibiotics when theyre needed, it is also very important NOT to use
them unnecessarily. This is because germs learn! Ever since mankind discovered and started
using the first antibiotics, we have literally been in a race with the germs to see if we
could invent new ones faster than they could figure out how to resist them. For example,
only 10 years ago 100% of Pneumococcus (the most common bacterial cause of pneumonia, ear
infections, sinusitis, and meningitis) were sensitive to Penicillin. Today, 20-30% of
Pneumococcus is resistant to that antibiotic, along with most others, and the percentage
grows every year. These resistant Pneumococci are difficult to treat, and very dangerous
as a result. Similar things have happened with other germs and antibiotics. Its been
inevitable that this would happen eventually since the day we started using Penicillin,
BUT, the more Penicillin we use, the sooner and quicker the germs learn how to circumvent
it. This plays out on a global, evolutionary scale - not at an individual level. Germs
will not suddenly become resistant inside your childs body while we or because we
are treating with a particular drug. Still, we will all be safer in the long run if we
the temptation to over-use antibiotics (as, for example, in the case of a viral
infection). Because of this, it is our policy at Childrens Medical Office never to
prescribe antibiotics over the phone. In general, we will need to do a physical exam first
- and then we will only prescribe when we have made a specific diagnosis which requires
antibiotic treatment, or when the likelihood of such a diagnosis is high enough to make
the risks of not treating higher than the risks of doing so.
Another reason we do not
prescribe antibiotics without examining you first is that it can be dangerous.
child had a more serious illness that really required treatment in the hospital with IV
antibiotics, and we were to start oral ones before seeing you, we could "mask"
the symptoms and cloud the diagnosis. The resultant delay and confusion in realizing what
was really going on could cause significant harm.
© 1998 Children's Medical
Office of North Andover, P.C