Plague Z (The Plague)

Plague Z was a plague that caused the infected to become stronger, but took control of their brains to infect more people by attacking them, turning them into "zombies". This global pandemic lasted for 7 years, staring from Patient Zero being infected on April 5, 2020 and the last zombie being shot down on July 27, 2027. During this 7-year time period, now known as The Zombie Years, the zombies attacked humans, and spread themselves to almost all countries of Earth. Almost 5 billion people died during these years, vast areas were left depopulated, and a 75-year long period of near-total anarchy followed the plague.

Symptoms
The infection is moderately contagious, with prolonged physical contact with a person for 3 minutes or more usually sufficing to infect a person. The infection will take about 2 days to 1 month for symptoms to register, depending on which part of the body was infected, it moves fastest in the circulatory and respiratory systems. In 30 minutes, the person receives a high fever of usually above 38 degrees Celsius (100 degrees Fahrenheit), then heavy coughing and sneezing sets in. Within 2 days of first symptoms, the infected person dies of rapid organ decomposition, and reanimates as a zombie within a week of death. The only two ways to kill a reanimated zombie is to destroy part or all of its brain, or starve them to death (they cannot go without human or animal flesh for more than 2 weeks). This makes the head and face their most vulnerable parts.

Zombie Physiology
The zombies look like normal humans, but their outer skin has decomposed, leaving the muscle on the outside, sometimes bones will stick out of the exposed muscle. They operate on anaerobic respiration, which means they do not need oxygen to survive, however, they need food in the form of human or animal flesh. They walk a little slower than humans, and they cannot run. However, they can jump and swim. Zombies are not sentient, as they operate on instincts to consume flesh and cannot think like humans do.

The Origins
Frozen for 34,000 years in a remote area of Northern Siberia, it was finally uncovered by a group of 37 Russian scientists in 2020. The virus was discovered 541 kilometers from Yakutsk, in the Sakha Republic, in Russia. All 37 scientists were infected by an ice core from the area which contained the virus. All 37 scientists managed to return to their hometowns without dying on the road. This meant that they managed to infect people inside their hometowns.

The Initial Infections
By mid-April 2020, dozens of reports came out about murders and cannibalism in 7 different Russian cities, namely Moscow, St. Petersburg, Volgograd, Kazan, Krasnodar, Yakutsk, and Krasnoyarsk. They found the disease inside a newly infected person in late April, and at first they named it the Cannibal's Flu, as they did not know about the zombification of the infected. The Russian government started work on a cure almost immediately. By early May, 3500 people were infected, and 473 were dead. By this point, several nations, such as Ukraine, Mongolia and Turkmenistan banned all travel to and from Russia, helping to slow the spread of the virus in these countries.

The Early Spread in Europe
In 19 May 2020, Russia closed all their airports, but several planes with infected people on board had left for multiple cities in Europe, including London, Paris, Berlin, Rome, Madrid, Warsaw and Stockholm. They started the spread in Europe. This led to many instances of civil unrest, including protests for making the cure, some of them escalated to riots in Western Europe, the dissolution of the EU in fear that open borders will increase spread of the disease, and multiple governments, mostly in the Balkans, resorting to radical means to control the disease and suppress riots, the extreme was Croatia setting fire to the entire cities of Dubrovnik and Split, killing 300,000 mostly healthy people. By the end of 2020, as many as 523,000 were infected and 125,000 dead (not counting radical disease control measures), and by late 2021, about 17 million were infected and 8.3 million dead in Europe alone. The figures in Asia were much higher.

The Early Spread in Asia
In 19 May 2020, Russia closed all their airports, but several planes with infected people on board had left for multiple cities in Asia, like Beijing, Shanghai, Hong Kong, Seoul, Tokyo, Singapore, New Delhi, Mumbai and Tehran. It spread fastest in China and India, and it killed much more people than in Europe. Many nations started taking military action to kill the zombies, but they didn't know how until somebody found out that they have to target the head. It helped, but there were so much zombies in China, India and Korea that the military was almost powerless there. Swarms of Chinese, Indian and Korean refugees took refuge in the islands and atolls of the Pacific, leading to overcrowding, unhygenic conditions, and permanent destruction of these islands' ecosystems. By the end of 2020, 3.9 million were infected with 1 million dead, and as many as 48.1 million were dead by early 2022. Vast areas of East, South and Southease Asia were depopulated, their populations either escaping to the Pacific Ocean islands or dead.