Anthrax is a rare but serious infectious disease caused by a spore-forming bacterium called Bacillus anthracis. Once inside the body, the spores can release toxins that damage tissues and organs. Anthrax mainly affects livestock and wild animals, and people usually become infected through contact with infected animals or animal products. Anthrax does not spread from person to person in the …

Chagas disease is a parasitic infection caused by Trypanosoma cruzi. It is primarily transmitted to humans through the bite of infected triatomine bugs, also known as kissing bugs. The disease is most common in parts of Latin America but can also be found in other regions due to travel, migration, blood transfusions, and organ transplants. Chagas disease has an acute …

Amnesia is when you have serious memory loss. It can be a symptom of other conditions or happen by itself. Amnesia comes from ancient Greek and means, “forgetfulness.” But it’s more than that. Forgetfulness is misplacing your keys or not remembering to do something while running errands. Amnesia involves being unable to remember significant events or details from your life. …

Transient global amnesia (TGA) is a rare medical condition in which you experience a sudden episode of memory loss. During a TGA episode, you can’t form new memories (a condition called anterograde amnesia), and you have difficulty recalling recent memories (a condition called retrograde amnesia). “Transient” means passing. Transient global amnesia episodes usually last no more than several hours. In rare cases, they …

Ampullary cancer is a rare type of cancer that begins in the ampulla of Vater. The ampulla of Vater is a small opening where the bile duct and pancreatic duct join and empty into the small intestine. This location places ampullary cancer close to several important digestive organs, including the liver, pancreas and small intestine. Because of where it starts, …

Amyloidosis is a rare disease that develops when an abnormal protein called amyloid builds up in organs and tissues. This buildup interferes with normal organ function and can lead to serious health problems. Amyloid deposits may affect one organ or multiple organs throughout the body. Organs commonly affected by amyloidosis include the heart, kidneys, liver, spleen, nervous system, digestive tract, …

Atypical genitalia, previously known as ambiguous genitalia, is a rare condition in which a newborn’s external sex organs do not appear clearly male or female. In some infants, the genitals may be underdeveloped, appear different from typical male or female anatomy, or show features of more than one sex. The appearance of the external genitals may not match the internal …

Lazy eye, medically known as amblyopia, is a vision development disorder in which one eye fails to achieve normal visual acuity, even with prescription glasses or contact lenses. It usually develops from birth up to about age 7 and is the most common cause of decreased vision among children. The condition occurs when the brain and the affected eye are …

Ameloblastoma is a rare, noncancerous tumor that most commonly develops in the jaw, usually near the molars. It begins in the cells involved in forming the enamel that protects teeth. Although benign, ameloblastoma can be locally aggressive and grow into the surrounding jawbone. The most common form tends to grow slowly but can become quite large if not treated. As …

Amenorrhea is the absence of menstruation and is commonly defined as missing one or more menstrual periods. It is not a disease itself but a sign of an underlying condition, natural body process, or hormonal change. There are two main types of amenorrhea. Primary amenorrhea occurs when a person has not started menstruating by age 15. This form is often …