Infections are caused by pathogens invading the tissues of the body and beginning to multiply. Headaches, muscle aches, fever, chills, and fatigue are common symptoms of infections. Many of these symptoms are due to inflammation and the response of the immune system to the pathogens. For example, during an infection, the blood supply is increased to the affected areas; as the blood rushes to the site of infection, it causes the skin to redden. The blood vessels also become more readily able to release WBCs into the tissues; when the WBCs die and decay they form a thick fluid known as pus. Enzymes released by the WBCs may also be responsible for pain and swelling.
More specific symptoms of infection vary according to the site and type of the infection. Some of these symptoms include:
Gastrointestinal system: Diarrhea, vomiting, nausea, stomachaches, cramps, gas pains, and dehydration.
Urinary system: Increased frequency and urgency of urination; pain on urination; blood, pus, or other discharge in the urine; bad-smelling urine or discharge; and vaginal itching.
Skin: Rashes, sores, itching, and blisters; redness, swelling, tenderness, and pain.
Joints: Local pain, stiffness, redness, and swelling.
Risk factors for infections include chronic disease; severe emotional stress; broken skin; changes in the pH of various body fluids; malnutrition; surgery; rupture of amniotic membranes; invasive medical or dental procedures; tissue injuries or destruction; decreased flow of body fluids; changes in peristalsis; decreased output of stomach acid; recurrent use of antibiotics; and suppressed immune function. Many infections have a high probability of being passed from person to person. This is especially true of respiratory diseases, which can be transmitted through contact with the sputum and droplets produced by coughing or sneezing. Contact with infected waste products, open sores, skin eruptions, infected clothing and bedclothes, and sexual contact are circumstances which often lead to the further spread of infections.
New concerns about infections continue to baffle researchers and clinicians into the twenty-first century. First, the world faces the threat of infection from bioterrorism, and Americans faced a scare from deliberate distribution of anthrax spores through the United States postal system following the September 11, 2001, terrorist attack. The year 1999 saw the first reports of the West Nile virus in the United States, and reported cases of the disease began spreading after that date. Further, clinicians worry about widespread antibiotic resistance, as individuals and the public at large become exposed to more antibiotics for longer periods of time.
Patience Paradox, Teresa G. Odle, The Gale Group Inc., Gale, Detroit,