Microbes are tiny single-celled organisms representing the oldest form of life on earth. The relationship between microbes and human being is complex and very delicate as some microbes keep human beings healthy while another cause sickness.
Some microbes require oxygen to live while others don’t, some flourish in freezing cold and others in the scorching heat.
Microbes aids in plant growth, oxygen supply, and break-down of dead organic material.
Microbes are better in adapting to the new environment than human beings and this put them in a better position to challenge human being with creative survival tactics like developing new properties which help them to resist drugs treatment. As the environment change, human beings are coming into contact with new microbes which were unknown to them previously.
Microbes causing diseases are called Pathogens and responsible for infectious diseases like flu and chronic diseases like some form of cancer and coronary artery diseases. This group of microbes only represents less than 5% of all microbes.
Microbes have caused infection and diseases to human beings since ancient times. Diseases such as smallpox, malaria, polio, and influenza, have killed millions of people in the past before vaccines were discovered. HIV is an infection that has continued to kill many people all over the world.
Most infections caused by pathogens fall into three groups:
- Acute infections: – These infections are very severe and last a short time. An example of acute infection is the common cold
- Chronic infections: – These infections can last for months or even lifetime, example is Hepatitis C
- Latent infections: – These are silent infections that may or not cause symptoms after the first acute episode.
Microbes are classified into four main groups namely:
- Fungi
- Bacteria
- Viruses
- Protozoa
Bacteria
Bacteria thrive in a variety of environments ranging from extremely cold to extremely hot. Psychrophiles is a kind of bacteria that thrives in cold, sub-freezing temperatures while thermophile thrives in extreme heat environments but many bacteria thrive in middle temperatures. Some bacteria require oxygen while others don’t require it for survival. Harmless anaerobic bacteria living in human Intestines aids in digestion, fighting diseases, and providing essential vitamins. Bacteria decompose a wide range of dead organic materials while some fix nitrogen to a form useable by plants.
Viruses
Viruses are smaller than bacteria and most of them invade living body cells. Some viruses called bacteriophages attack bacteria and are useful to the scientist in the development of medicine for preventing and treating bacterial infection. Most viral infections do not cause diseases but other infections can cause deadly diseases like AIDS and Ebola
Fungi
Different types of fungi exist in the world. Some of the commonly known are mushrooms, mold, yeast, and mildew. Diseases caused by fungi are called mycoses and usually affect the skin, body hair, and lungs. Other types of fungi have made life easier for a human being. A good example is Yeast which aid in fermentation, an important process in the preparation of healthy food like bread and wine. Penicillin and other antibiotics are made from fungi. In soil, fungi break down resistant gums, cellulose, and lignin. They usually dominate acidic, sandy soils.
Protozoa
Protozoa can be predators or parasites depending on where they thrive. In the human being, they usually disease like malaria. In a water environment, protozoa, like plankton are a source of food for marine animals. In order for them to survive, they must be in a moist environment.