China reported its first imported cases of the Zika virus this month, adding another malady to the deleterious list of diseases that have plagued the region, a list that includes the almost annual occurrence of avian flu and the Sars outbreak in 2002.

For much of its history, China associated its southern regions with zhangqi, or “miasmic humours”, which supposedly caused illnesses and ailments such as malaria, influenza, parasitic fevers, heat stroke, gastroenteritis and so on. These potentially fatal diseases were erroneously perceived by northerners as endemic to the south.

The perception also acquired a cultural dimension, with the Han Chinese in the north, many of whom considered the northern central plains to be the fount of a superior culture, viewing the southern regions as an exotic, mysterious and disease-ridden place peopled by ill-favoured barbarians.

The geographical location and size of China’s “deep south” had changed over time in tandem with the expansion of the Han-Chinese civilisation: from the vast regions south of the Yangtze River in the pre-imperial period (before the third-century BC) to the Lingnan region (which includes present-day Guangdong and Hong Kong) in the next millennium and a half, and finally to Yunnan and Guizhou in the Ming and Qing dynasties (1368-1911).

Nowadays, no one believes that Lingnan and Yunnan are rife with miasmic humours, but all over China, noxious fumes from factories, coal burning and cigarette smoking are wreaking havoc on people’s health and causing untimely deaths.