Infectious Disease

Introduction A doctor preps for surgery by thoroughly washing his hands. The tools are put through either an acid wash or an autoclave that super heats the tools. In olden times this was definitely not the case. Some soldiers would have limbs amputated in the field and dressed with dirty bandages. Many would die days later. Women gave birth, and then, would die of childbed fever. Doctors had no idea why.

Definition of Infectious Disease Why did these men and women die? These people died from infectious diseases from the unsanitary conditions. Infectious diseases are diseases cause by the presence of a living thing inside of the body. Pathogens get inside of your body and cause harm, when you have a sore throat, pathogens have damaged cells in your throat. In the past, people often thought that it was swamp air or evil things that led to sickness. They did not know about pathogens.

Different types of Pathogens A group of scientists including Louis Pasteur found that certain microorganisms cause certain sicknesses. He also found ways to kill these pathogens and help prevent diseases. German physician Robert Koch found that specific pathogens caused specific disease. For example one kind causes pneumonia and a different one causes strep throat. There are four major types of pathogens: bacteria, virus, fungi, and protists.

Bacteria Bacteria are a one-celled organism that cause a variety of infections from ear infections to food poisoning. Strep throat is caused by streptococcus bacteria. Bacteria can damage cells directly or indirectly by producing toxins. If the bacteria tetanus gets into an open wound it produces a toxin that damages the nervous system causing the jaw to lock up.

Diagram of Bacteria

Viruses Viruses are small particles that are even smaller than bacteria. Viruses can only reproduce when they are inside a living cell and this destroys the cell in the process. Colds and the flu are caused by viruses invading the respiratory system. There are over 200 different types of cold viruses.

Diagram of Viruses

Fungi Fungi are small organisms that produce mold and yeasts. Many different types of fungi can invade skin cells causing painful rashes. Two of the most common types of fungi are athlete’s foot and ringworm. Fungi growths the best in warm, moist, and dark areas so a tennis shoe makes for a perfect environment.

Diagram of Fungi

Protists Protists, like bacteria, are single-celled organisms. Unlike bacteria, protists contain their own nucleus. Malaria which is an infection of the blood is caused by a protist. Many diseases that are caused by protists thrive in tropical areas.

Diagram of Protist

How are Pathogens Spread? Pathogens need food to survive and shelter just like other organisms. This means your body or the body of another organism. You can become infected with a pathogen several ways: contact with an infected person; through soil, food, or water; contaminated object; or infected animal.

Infected People Pathogens can pass through direct contact with people. This includes kissing, hugging, or shaking hands. Pathogens are also spread through indirect contact. This includes coughing and sneezing. A sneeze can travel up to 20 mph and have a radius of 5ft.

Soil, Water, and Food Pathogens occur naturally in the environment. A bacteria that causes food poisoning lives in the soil. This bacteria can produce toxins in canned foods that were not processed correctly. Cholera and dysentery are spread through water. If you eat or drink a contaminated source then you could contract a disease.

Contaminated Objects Some pathogens can survive outside of a host. People can come in contact with these by simply touching an object such as a doorknob, spoon, or towel. The cold virus is simply transferred by touch. Remember to wash your hands!

Infected Animals If an infected animal bites a person then that person can become infected. People have gotten rabies, a serious disease that affects the nervous system, from raccoon and dog bites. Lyme disease is another serious disease that is spread through the bite of a deer tick. Mosquitos can transfer many different diseases such as Malaria and West Nile Virus.

Conclusion Infectious diseases are pathogens that invade our bodies and cause use harm. There are four major categories of pathogens: bacteria, viruses, fungi, and protists. Pathogens are spread in a variety of ways: contact with an infected person; soil, food, and water; contaminated object, and infected animals.

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