The outbreak of the K-Z Virus on the night of July 20, 2016 was met with both hysteria and shock through much of the international community. The news of a zombie-like virus seemed unbelievable at first until more and more videos of "rioters" attacking both citizens and police made it all to real. However, thanks to the zombie pop-culture started by George Romero in 1968, revived by Danny Boyle in 2002 with 28 Days Later, and made into a survival guide by Max Brooks in 2003, some Doomsday preppers finally thought it was the time of their lives. Pop-culture actually played a big role in the preparation for minimizing the spread, thanks to numerous video games and the fame of the TV series The Walking Dead.
Across the United States, sales of guns, supplies, and survival gear incredibly skyrocketed just 12 hours into the outbreak. Various counties as far as Southeast Asia, Oceania, Europe, and South America began mobilizing their armies and setting up possible retreat points if an outbreak occurred. Despite the fast spread of the virus which covered roughy 90% of South Korean territory in just 24 hours, it also meant that the outbreak would be contained there. Bites were impossible to hide as victims would turn in 10-12 seconds. Plus, it would be impossible for the virus to spread beyond land territory, as it would meant the Infected could only reach the victim within running distance. This comes in addition to the fact that the Infected were still technically alive and hence could be prone to damage or injury that would harm a human. Perhaps humanity's greatest blessing was the fact the Infected could neither swim or walk on the bottom of the seafloor or a river; any that tried to cross was seen helplessly flailing around until they drowned. This is one of the reasons why the virus was only contained within Korea.
Yet, as the virus stabilized and the South Koreans backed by the U.S. and their allies were slowly retaking the peninsula, theories began spinning wild among who or what was the cause of the outbreak. Theories included a North Korean attack as a pretext to an invasion (see below), an accident at a laboratory, mutation of the rabies virus, a U.S. government false flag operation, ISIS obtaining a secret weapon and using it on an unlikely location, Donald Trump's (then a Presidential candidate) ticket to the White House, and lastly, a space-borne alien virus. As absurd as it might sound, some of the theories did coincidentally almost become true.
The Democratic People's Republic of Korea planned for a "liberation campaign" to their brothers in the South, promising to "rid the filth" from the "capitalistic and imperialistic" disease plaguing them. Though Kim Jong-un knew the virus originated from Seoul, it was chance to put the blame of the United States and their "warmongering" policies. Even worse was the fact he had ordered the Korean People's Army to capture Infected specimens to use as bioweapons in causing a distraction within the Busan Safe Zone in addition to various U.S. military bases in Japan plus several Japanese major cities. From there, his KPA would come past thundering the DMZ and bring reunification to the Korean Peninsula once and for all. Unfortunately, his plan would fall apart as majority of the U.S. and its allies easiy defeated his invasion forces while his biological attack plans were foiled by Korean UDT Special Forces. Even worse was the world now blamed Kim and his regime for starting the outbreak as the evidence was nearly undeniable. Because of Kim's madness and the risk of the virus spreading into Russia and China, disgruntled elements of the DPRK staged a coup backed by the People's Liberation Army which arrested Kim and replaced him with a civilian government which sued for peace on the 3rd day of the Second Korean War.
Politically, other theories include a deliberate attempt by then-President Park Gyun-hye in trying to hide the allegations of corruption with her administration. While these were brought to light by early 2016, the outbreak had to postpone the investigation until the country stabilized (after all, what good would a country be without a leader?). As of 2018, former President Park is still being investigated in relations to the accusations.
For Trump, the outbreak did ensure he had a clear ticket to the White House in November 2016 elections. His margin was larger than expected, definitely squashing any resistance Hillary Clinton posed. The larger turnout was mainly caused by the fear of illegal immigrants bringing in the K-Z Virus (or any virus) that would harm national security of the United States. Despite this, thousands of liberals and college millennials still protested against the results, even crying foul despite the electoral collage being in the favor for Trump. As with OTL, riots and shutdowns occurred throughout major cities across the U.S. though this would be dispersed immediately by police and the National Guard who were still on alert in case of a sudden appearance of the K-Z Virus.
Once and for all, it was proven on December 14, 2016 that the virus did indeed come from the Bio-Tech Corporation, a pharmaceutical company based in Seoul. Investigators were able to pinpoint an accident at the testing labs which most likely infected a dog with rabies that caused the virus to mutate before crossing into humans. The CEO was held responsible and warrant of arrest was issued but by the time the police raided his home, he was found to have committed suicide by hanging.
To this day however, many are still not convinced it was an accident and they go on insisting there was a much more sinister motive behind the outbreak.