Helicobacter Pylori Infection The bacterial infection H. pylori is most commonly recognized for causing circumscribed lesions in the mucosal membrane, or peptic ulcers. H. pylori releases a toxin that promotes…

Haverhill Fever Haverhill fever—also known as rat-bite fever, sodoku, streptobacillary fever, streptobacillosis, spirillary fever, and epidemic arthritic erythema—is an infection that usually results from handling or being bitten by an…

Haemophilus Influenzae Infection Droplet Precautions H. influenzae can cause diseases in many organ systems but usually attacks the respiratory system. H. influenzae is one of the three most common organisms…

Gonorrhea Contact Precautions Gonorrhea is a common sexually transmitted infection that usually starts as an infection of the genitourinary tract, especially the urethra and cervix. It can also cause infection…

Gingivitis Gingivitis is inflammation of the gingiva, which is part of the soft-tissue lining (gums) of the mouth that surrounds the teeth. Gingivitis is classified according to its appearance (ulcerative,…

Giardiasis Contact Precautions Giardiasis (also called Giardia enteritis) is an infection of the small bowel caused by the symmetrical flagellate protozoan Giardia (duodenalis) lamblia. A mild infection may not produce…

Gastroenteritis Contact Precautions Gastroenteritis (also called intestinal flu, traveler’s diarrhea, dysentery, viral or bacterial enteritis, and food poisoning) is an inflammation of the stomach and small intestine that is usually…

Gas Gangrene Gas gangrene is caused by local infection with the anaerobic, spore-forming, gram-positive rod Clostridium perfringens (or another clostridial species). It occurs in devitalized tissue and results from compromised…

Folliculitis Contact Precautions Folliculitis—a bacterial infection originating in the hair follicle—causes the formation of pustules. The infection can be superficial (follicular impetigo or Bockhart’s impetigo) or deep (sycosis barbae). Folliculitis…

Filariasis Filariasis is a parasitic infection that is classified according to the body cavity inhabited by the parasite. The areas most commonly affected are cutaneous and lymphatic, but other body…