a disease is considered as rare disease if
Rare disease In the United States, the Rare Diseases Act of 2002 defines rare disease strictly according to prevalence, specifically "any disease or condition that affects fewer than 200,000 people in the United States",[3] or about 1 in 1,500 people. This definition is essentially the same as that of the Orphan Drug Act of 1983, a federal law that was written to encourage research into rare diseases and possible cures.
Leprosy Leprosy is spread between people and possibly from armadillos.[7] This is thought to occur through a cough or contact with fluid from the nose of an infected person.[7] Leprosy occurs more commonly among those living in poverty.[2] Contrary to popular belief, it is not highly contagious.[2] The two main types of disease are based on the number of bacteria present: paucibacillary and multibacillary.[2] The two types are differentiated by the number of poorly pigmented, numb skin patches present, with paucibacillary having five or fewer and multibacillary having more than five.[2] The diagnosis is confirmed by finding acid-fast bacilli in a biopsy of the skin or by detecting the DNA using polymerase chain reaction.[2]