often called infectious diseases. Some diseases can be transmitted more easily than others. The disease process begins when a pathogen or germ gets into the body. These pathogens can enter the body through the nose and mouth and genital organs and affect the different systems of the body. Most infectious diseases are caused by one of six pathogens. The most common ones are bacteria and viruses.

Bacteria are everywhere. They do not depend on other organisms for life and can live outside of the human body. Bacteria can cause serious illness.

Meningitis, tuberculosis, food poisoning and sexually transmitted diseases are examples of disease caused by bacteria. The body has difficulty fighting infections caused by bacteria and therefore medications called antibiotics are prescribed to either kill the bacteria or weaken them enough for the body to rid itself of them. Commonly used antibiotics are penicillin, erythromycin and tetracycline.

Unlike bacteria, viruses depend on other organisms to live and reproduce.

Viruses cause many diseases. Some common diseases are the cold, influenza AIDS, hepatitis, chicken pox and herpes to name a few. Once they become established within the body, they are difficult to eliminate because very few medications are effective. Antibiotics do not kill or weaken viruses. The body's immune system is the main defense against them.

The body's immune system is very good at fighting disease. Its basic tools are the white blood cells, with special white cells identifying invading pathogens. Once these pathogens are detected, these white blood cells gather around the pathogen and release antibodies that fight the infections.

Antibodies usually can get rid of the pathogens, but some can thrive under idea conditions and overwhelm the immune system as in the case of HIV, the virus known to cause AIDS.

This combination of trying to keep pathogens out of the body and destroying them once they get inside is necessary for good health. When the immune system cannot rid the body of the pathogen, then serious infection occurs. Fever, fatigue, headaches, nausea and vomiting are signals that the body is fighting an infection.

For a disease to be transmitted four conditions must be met. A pathogen must be present, there must be enough of the pathogen present to cause disease, a person must be susceptible to the pathogen and the pathogen has gained entry into the body through the correct entry site.

Pathogens enter the body through direct, indirect, airborne and vector borne transmission. Direct transmission occurs when a person touches body fluids from an infected person. Indirect transmission occurs when a person has touched objects that have touched the blood or body fluids of an infected person. Airborne transmission occurs when a person breathes in droplets that become airborne when an infected person coughs or sneezes. Vector transmission occurs when an animal such as a dog or an insect, such as a mosquito, transmits the pathogen through a bite.

Some diseases can cause severe problems where the patient can be seriously ill and slow to recover. Other diseases cause death. Diseases that cause considerable concern in the community are tuberculosis, hepatitis and AIDS.

Many diseases can be prevented. This begins with maintaining good health and always practicing good personal hygiene, such as washing hands before and after food preparation, using the toilet, abstinence from sex or use safer sex practices. Others can be prevented by vaccinations against diseases such as influenza childhood diseases, hepatitis B and tetanus to name a few.

If you should have an infectious disease, seek medical attention and limit your contact with others until you have recovered from your infection.

---- Rhonda C.K. Daniels, Nurse Epidemiologist, Health Department HEALTH HTH