Three main types of infection can affect both animals and plants. Bacterial infections are quite common, and these occur when single-celled microorganisms, known as bacteria, invade an organism. Viral infections, like influenza, are caused by viruses, and can be somewhat difficult to treat. Fungal infections are caused by fungi, and these usually develop on a person's skin.
A bacteria infection is one of the most common types of infection. Not all bacteria will cause an infection, though. In fact, many of the countless types of bacteria found on the human body are considered to be good bacteria, and they are necessary for proper body function. If one of these types of bacteria grows out of control, however, or if humans come in contact with a bad bacteria, a bacterial infection is usually the result.
Staphylococci and streptococci are two very common types of bacteria that can cause infection. Skin infections like cellulitis and impetigo are often caused by a staph infection, while strep throat is a good example of a strep infection. Treatment usually requires an antibiotic administered either orally or topically. Bacterial infections are becoming harder to treat, however, since many types of bacteria are becoming resistant to antibiotics.
A viral infection is caused by a virus, which is an organism that consists of a nucleic acid molecule surrounded by a protective protein shield. When a virus invades a body, it takes over a living cell. It causes the cell to produce more viruses, which will often lead to these types of infection.
Chickenpox and influenza are both caused by viruses, as are HIV and AIDS. Antiviral medications can sometimes be used to treat certain viral infections. These are not always effective, however, since they only work on very specific strains of viruses.
A fungal infection is another one of the more common types of infection. This type is caused by a fungus, which is classified as a plant. Fungi can live just about anywhere, including on another living organism. They can also be found in the air, soil, and water.
Fungal infections are some of the most common causes of skin infections. Fungal infections of the mucus membranes, however, are also quite common. Athletes foot, ringworm, and yeast infections are all caused by a fungus. Topical antifungal medications are usually all that is necessary to treat an fungal infection.