Why did SARS only become an epidemic in China and in Toronto, the part of Canada where many Chinese emigrants live? Scientists have found a genetic susceptibility to SARS that explains this puzzle.
Maggie Fox writes that a variant in an immune system gene called human leukocyte antigen, or HLA, makes certain patients much more likely to develop the life-threatening symptoms of SARS. This gene variant is common in people of southern Chinese descent.
“After the outbreak of SARS coronavirus infection in the Guangdong Province of China, it was surprising to observe that the spreading of the disease was mostly confined among southern Asian populations (the Hong Kong people, Vietnamese, Singaporeans and Taiwanese),” researchers write.