How Does The Body Defend Against Infection

Suppose a pathogenic agent (an organism that is capable of causing an infection) does invade the body. The threat is that it will cause disease, either because it is present in great members (as in pneumonia) or because it can release toxins (as in botulism, TSS, tetanus, or diphtheria). What can the body to do fight off the pathogen?

The Outer Defenses
The skin and mucous membranes are the body’s first line of defense. An invading microbe must find its way through the skin or the mucosae, the mucus-coated membranes that make an “inner skin” for the body by lining the respiratory, digestive, and urogenital tracts. Here are also secretions, such as tears, perspiration, skin oils, and saliva, that contain chemicals that can kill bacteria. In addition the respiratory passages are lined with fine, short, moving hairs called cilia. Beating in synchronized fashion, the cilia move a carpet of sticky mucus. The mucus works like fly paper to trap inhaled microbes and foreign matter and carry them to back of the throat, where they are removed by sneezing, coughing, or nose-blowing, or are swallowed and disposed of by digestive fluids.

Besides the cilia, other body hairs (the eyelashes, for example) may fend off invading microorganisms. Our reflexes (coughing, blinking, vomiting) are also part of our body’s firs line of defense. High acid levels in the stomach and vagina also help destroy invaders.

Charting Immunity History

We can prevent many communicable diseases through vaccination. And we may be immune to certain other diseases if we've actually had these diseases, they produce immunity for varying lengths of time their actions on our bodies.

 

What disease are you immune to? Look to communicable diseases listed below. Have effective vaccines been developed for all of them? Check those that have vaccines, then write vaccinated for it. You may need to consult your parents, your family physician, or some other source to obtain some of this information.

 

No.	Had the Diseases	Initial Vaccination	Most recent Vaccination	Length of time this Immunization will last
1.    Ordinary ("red") Measles
2. German Measles
3. Mumps
4. Flu
5. Polio
6. Whooping cough

 

Immune mean in order to prevent a disease from spreading, scientist don't know far below 100% immunity we can go in our population without having new outbreaks of these diseases. So it's important for all of us to keep our own vaccinations up to date and to urge others to do the same. Check back to see when you last had your "shots" and find out when you should go for any further shots or booster.

 

Recommended Schedule for Active Immunization

 

Age (months)	Vaccines
2	Diphtheria-tetanus-pertussis (DTP), Oral polio vaccine
4	DTP, oral polio vaccine
6	Oral polio vaccine
15	Measles, rubella, mumps
18	DTP, oral polio booster
4 to 6 years (school entry)	DPT booster, oral polio booster
14 to 16 years	Combined tetanus and diphtheria toxoid, Adult type (repeat every 10 years)