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Multiple sclerosis is a condition wherein the body's nervous system is weakened by an autoimmune reaction that attacks the myelin sheaths of neurons.
Pope Sylvester II tried to introduce Arabic numbers into Europe between the years 999 and 1003, but their use did not catch on for a few more centuries, and Roman numerals continued to be the primary number system.
Though Candida and Aspergillus species are the most common fungal pathogens causing invasive fungal disease in the immunocompromised, infections due to previously uncommon hyaline and dematiaceous filamentous fungi are occurring more often today. Rare fungal infections, once accurately diagnosed, may require surgical debridement, immunotherapy, and newer antifungals used singly or in combination with older antifungals, on a case-by-case basis.
Malaria was not eliminated in the United States until 1951. The term eliminated means that no new cases arise in a country for 3 years.
Only one in 10 cancer deaths is caused by the primary tumor. The vast majority of cancer mortality is caused by cells breaking away from the main tumor and metastasizing to other parts of the body, such as the brain, bones, or liver.