Infectious diseases are illnesses caused by germs (viruses, bacteria, fungi or parasites). They cause infections that disrupt the bodies normal processes and/or stimulate the immune system to produce a defensive response, which can result in high fever and inflammation. Some infectious diseases can be deadly and some resolve with no complications.
Infections are generally classified as contagious, meaning they can spread from one person to another. Some contagious diseases are passed directly from an infected person to a healthy person, while others may be transmitted by touching or sharing personal items such as toothbrushes, razors or needles that have been used by the infected person. Some contagious disease symptoms include coughing, sneezing and the exchange of body fluids through sexual contact.
Symptoms for some infectious diseases, like hepatitis A and hepatitis B, are severe and can lead to death. The symptoms can vary depending on the type of infection and where it is located in the body, and can include fever, pain or vomiting.
A doctor will likely order several tests to diagnose an infection and narrow down the possible causes of the illness. These tests can include sputum swabs, throat swabs, stool samples, blood cultures and a spinal tap or lumbar puncture.
Most doctors will be able to make a diagnosis of an infection by reviewing the patient’s history, physical examination results and risk factors. In addition, they may recommend imaging procedures to help diagnose the disease and rule out other conditions that can cause the same symptoms, such as pneumonia, asthma or heart failure.
Bacteria are microscopic organisms that can enter the body and multiply, causing infection. They can cause many different kinds of illnesses, from a common cold to life-threatening diseases such as meningitis or tuberculosis.
They usually live on the surfaces of the skin, mucous membranes and in the body’s organs. Some bacteria can even get into the lungs and cause infection there. Other types of bacteria, called staphylococci and streptococci, cause septicemia with fever, inflamed surface lining cells, and destructive abscesses that can form in the lungs or in other organs.
Some bacteria can also get into the eyes or ears, and cause infections in those areas. Those bacteria can cause a wide range of problems, including blindness and hearing loss.
Fungi are tiny, spore-producing organisms that can cause infections of the lungs, skin and nails. They can also affect the brain, intestines and bones.
Most fungi are harmless, but some can cause serious diseases. They can cause conditions such as candidiasis, thrush and vaginal yeast infections.
Infectious diseases can be prevented by ensuring that you wash your hands after using the bathroom, or after handling food, and by getting vaccinated. Vaccines can prevent the spread of some infections and reduce the severity of other ones, including the flu.
The most important way to avoid becoming sick with an infectious disease is to follow the advice of your doctor and stay home when you are ill. The sooner you can start treatment, the better your chances of recovering quickly and effectively.
