China and Hong Kong have often had periods of time when they were damaged by disease, famine, droughts, and the like. In many cases, they are also the victims of plagues.
The first known global outbreak of plague was in the 6th century, beginning near the middle east. It spread to Egypt, Rome, and Europe and had outbreaks in many more places before it eventually stopped in the 8th century. The next outbreak may have started in China in the 13 hundreds, accompanied by locusts, earthquakes, and floods. It spread to Europe, Asia, and even as far as Italy. The plague came and went, but stayed in Europe until the 17th century.
In the 19th and 20th century, however, Hong Kong was plagued. From there it spread to many places, including the U.S.A. when two plague victims were on a trading ship to San Francisco. In the end, as many as 200 million have died from the plague total, about one million of them from Hong Kong.
Transfer of the disease is caused by the bite of an animal or insect. Almost any animal can be a host for the plague, from a rat to a domestic dog, and even camels and sheep. The most common insect with plague is the rat flea, although human lice can also be a carrier. You can also get it by inhaling airborne things with the plague, or even being in contact with plague infested tissue. Symptoms include aches, fevers, chills, vomiting, heart failure, and even seizures.
In 1897, a vaccine was made by Waldemar Haffkine. Over the next few years, people found that the spreading of the plague was caused by the rat and the flea. Now we have more advanced ways to ward of the plague. Now we need to keep working on famine, droughts, and the like.