Germs are everywhere: in the air, soil, water, food, plants, and animals—even in and on the body. They include larger parasites and worms, and the more common single-celled bacteria, viruses, and fungi. Understanding these germs can help you better arm your immune system and avoid infectious illnesses.
Fungi. Fungi—like molds, yeasts, and mushrooms—are often single-celled organisms that are slightly larger than bacteria and reside in the air, water, soil, and plants. They can also live in the body. Some fungi, like penicillin, are beneficial. Breads, cheeses, and yogurts are also derived from fungi. Other fungi, like Candida albicans, can cause systemic infections in the gut, mouth, throat, toenails, vagina, and more.
Bacteria. One-celled organisms that can be seen through a microscope, bacteria are self-sufficient and multiply by subdivision. Although many bacteria can survive in unusually harsh conditions, most not only thrive in the body but they actually help the body. Lactobacillus acidophilus (L. acidophilus), for example, helps digest food and aid in nutrition while destroying disease-causing organisms.
But infectious bacteria can enter the body and rapidly reproduce. Many produce cell-damaging toxins that make you sick. Some of these invaders include strains of Escherichia coli (E. coli) which cause gastrointestinal upset and often come in through contaminated food.
Viruses.Viruses are even smaller than bacteria and contain the genetic material DNA or RNA. While their primary mission is to reproduce, unlike the self-sufficient bacteria, viruses require a host. They invade a cell, then take over and cause that host cell to reproduce, eventually destroying the host cell in the process. Common viruses include the common cold, the flu, Hepatitis (A-E), Epstein-Barr, and HIV (the virus that causes AIDS).