Many of the epidemics and pandemics in modern times originated in China. For example, the Asian Flu (1956-1958), SARS (Severe Acute Respiratory Syndrome) in 2002, H7N9 in 2012, etc. all started in China. Of course, the country is also the source for the current coronavirus pandemic (Covid-19). The reasons for why China is the originator of many deadly diseases are many. The following excerpt from an article early this years offers a few:

All of these outbreaks originated in China, but why? Why is China such a hotspot for novel diseases?

“It’s not a big mystery why this is happening… lots of concentrated population, with intimate contact with lots of species of animals that are potential reservoirs, and they don’t have great hygiene required. It’s a recipe for spitting out these kinds of viruses,” Dr. Steven Novella recently opined on an episode of the Skeptics’ Guide to the Universe.

South Central China is a noted “mixing vessel” for viruses, Dr. Peter Daszak, President of EcoHealth Alliance, told PBS in 2016. There’s lots of livestock farming, particularly poultry and pigs, with limited sanitation and lax oversight. Farmers often bring their livestock to “wet markets” where they can come into contact with all sorts of exotic animals. The various birds, mammals, and reptiles host viruses that can jump species and rapidly mutate, even potentially infecting humans. Experts are pretty sure this is precisely what happened with the current COVID-19 coronavirus, which is why, on January 30th, China issued a temporary ban on the trade of wild animals.

There are also cultural reasons why China plays host to large outbreaks.

“Many Chinese people, even city dwellers, insist that freshly slaughtered poultry is tastier and more healthful than refrigerated or frozen meat,” journalist Melinda Liu wrote for Smithsonian in 2017. “The public’s taste for freshly killed meat, and the conditions at live markets, create ample opportunity for humans to come in contact with these new mutations.”

Source: Why Do New Disease Outbreaks Always Seem to Start in China?, Real Clear Science

While doing some research online I came to know about the Manchurian plague of 1910-11 which also started in China. From an article on this plague:

In the autumn of 1910, the press in China began to report that a rare and deadly pneumonic plague had reached Harbin in the extreme Northeast of China, then known as Manchuria.[1] Though confined largely to China’s Northeastern provinces, cases were reported sporadically throughout the empire, in Tianjin, Beijing and along the Beijing-Hankou railway line stretching down into central China, reflecting the scale of the epidemic.[2] It is difficult to attain precise statistics about the death toll of the plague; however reports suggest that between 50,000 and 60,000 people died, with an unprecedented mortality rate of 100 per cent.[3] As a point of comparison, this places the death toll of the Manchurian plague in the same region as that of the more familiar Great Plague of London (1665-66).[4]

CAUSATION

The plague is likely to have originated amongst tarbagan marmot hunted for their fur in Manchuria.[5] As the German chemical industry developed new dyes, cheap marmot fur could be manufactured into imitation sable, mink and otter fur.[6]Consequently, the value of marmot fur rose from a ‘few kopecks a skin to a rouble’, causing migrant hunters to flock to Manchuria. These migrants, however, were inexperienced. Whereas local hunters, many of whom were from the region’s Buryat ethnicity, could identify and avoid diseased marmots, the migrant hunters collected unhealthy marmots, infecting themselves with the plague bacilli the diseased animals carried.[7]

The spread of the plague was exacerbated by the bitter cold of the northern winter, which caused the hunters to huddle together in huts, quickly spreading the airborne pneumonic plague. Manchuria’s extensive railway network further aided the rapid transmission of the disease by facilitating the movement of large numbers of migrant workers returning home for the New Year Festival.[8]

From Khailar in October the plague spread to Harbin, where thirteen cases had been reported to be ‘fatal’[9] and by November 8^th the city had a death toll of 5,272 deaths. Quarantine and control had been put in place in order to prevent the spread, however by January, Mukden (today’s Shenyang) had over 2,571 deaths,[10] soon spreading south to the capital city, Peking where an additional five cases were found.[11] Thus, the plague quickly spread throughout towns and cities along the railway lines in Manchuria, thriving in areas defined by ‘dense population, high human mobility and poor hygiene conditions’.[12]Subsequently, cities throughout Manchuria experienced high death rates, such as Kuancheng, near Jilin, which reported over 200 deaths per day.[13]

Due to the popularity of the relatively cheap, third-class tickets offered by the South Manchurian Railway most cases of plague infected cities along the rail line first, then spread further to small villages, with some being reported as far as Tientsin.[14]There were fears it would spread further, especially to Peking, as workers travelled home and shopped for Chinese New Year (30^th Jan). The worst hit areas were the crowded provincial capitals Changchun, Harbin, and Mukden, with deaths of up to 150, 130, and 60 daily respectively.[15] The majority of infections fell on poor, middle-aged Chinese who lived in crowded conditions with poor sanitation; very few foreigners contracted the plague, if so, they were medical staff.[16]^,[17] Through carrying out recommended procedures (isolation) infection in most cities and villages died out within two weeks; by the middle of March, Manchuria had resumed normality with plague existing only in hospitals. Schools, factories, and businesses including the whole of the South Manchurian Railway were open, working harder to recover lost ground.[18]

Note: All the references noted above are in the linked site.

Source: Manchurian plague, 1910-11, Investment Office

The entire article is worth a read. History does indeed repeat itself even with respect to pandemics, epidemics and plagues.