Cordyceps brain infection (HBO series)

The Cordyceps brain infection (abbreviated as CBI) is a parasitic fungal infection that has devastated mankind in HBO's The Last of Us.
== History ==
The Cordyceps brain infection is implied to be the result of global warming causing mutations in fungi like Cordyceps, allowing it to thrive in human hosts. This theory was postulated in 1968 by epidemiologists Neuman and Schoenheiss, in which they discussed the possibility of fungi mutating to cause a global pandemic. The theory became a reality in 2003 when a mutated strain of Cordyceps, classified as , started infecting people who ate contaminated flour-based food and other derived products. The index case was located in Jakarta, Indonesia.HBO's The Last of Us episode 2: "Infected" and caused an of violence in the city. Due to Jakarta being one of the leading world exports in flour and grain, it then spread to the and the rest of the world, causing a complete breakdown of global civilization.HBO's The Last of Us episode 3: "Long, Long Time" Referring to the flour and grain factory in Jakarta, Mycology Professor Ratna Pertiwi remarks that the location provides an excellent substrate for the fungus.
Upon infection, the Cordyceps grows while the host is still alive, with victims exhibiting symptoms including coughing, slurred speech, muscle spasms, and mood changes during the progression of the infection until it completely takes over higher brain function. Victims become animalistic, hyper-aggressive, and unable to reason or think rationally, relying solely on the warped basic instinct to feed leading to a desire to spread the infection to as many as physically possible. The fungus has also been shown to be capable of restoring physical functions to deficient hosts: when someone with impaired movement is infected, they can regain movement, even including the ability to run.
The infection can also be transmitted by bites from live hosts. In such a case, the time the victim has before transforming into an infected will depend on where they are injured: if it is on the neck, face, or head, they will transform in 5-15 minutes; if on the torso, arm, shoulder or hands, 2-8 hours; if on the legs or feet, 12-24 hours. Hosts can only be infected while alive, as the fungus is unable to infect dead bodies due to its parasitic nature.HBO's The Last of Us episode 1: "When You're Lost in the Darkness" Other than observation of signs of infection and symptoms, other tests for infection include dogs, which are capable of detecting the fungus within a human before the fungal infection becomes visible on the person's body, and electronic biometric scanners.
== Characteristics ==
In 1968, Neuman explained how the Cordyceps would infect insects, like ants, first infesting their bloodstream then reaching their brains, where it would flood them with hallucinogens that would manipulate the host's will and lead them to do as the fungus desired. Neuman specified that fungus differed greatly from viruses in that its aim was to control, not kill, hosts. In particular, he noted how the Cordyceps would replace its host flesh with its own and then prevent decomposition so the host could remain alive and serve its need to spread its spores to other non-infected animals. 
Before 2003, the Cordyceps could not infect humans. However, Neuman noted that an increase in the world's temperature to an average above 94 degrees Fahrenheit would be enough for it to do so. By the summer of 2003, this was made possible due to the effects of global warming. Neuman also explained that there was no cure for Cordyceps or any fungal infection of that nature.
The fungus also grows underground, with an extensive system of fibers growing miles long. Thus, disturbing one patch of Cordyceps could awaken another one with a horde of infected hosts lying dormant up to one mile away.
According to , the Cordyceps was characterized by a need to protect its growth through violence. He believed it was fruitful and was a sign of "love" in nature's most pure form.HBO's The Last of Us episode 8: "When We Are in Need"
== Behind the scenes ==
* As opposed to the games, the infection in the television series breaks out in 2003 as opposed to 2013. The show's producers explained that they wanted to make the series feel more grounded than based on speculation about the future, and to set the show in the year of its release (2023). Elements of the post-9/11 paranoia that defined the early 2000s are seen with regards to the pandemic, as wonders if the pandemic was spread by terrorists.
* According to co-creators and , how Cordyceps propagates is different from the games. Because of this, the fungus spores, which made survivors wear gas masks to avoid infection, will not be present in the show.Saksena, Sanchay (January 10, 2023). "The Last of Us HBO Series Will Feature Tendrils Instead of Spores; Modders Bring Bella Ramsey to the Game and More. IGN India. Retrieved January 16, 2023.
* While in the game series, Marlene stated that Dr. Jerry Anderson could create a vaccine against Cordyceps by reverse engineering the fungus extracted from Ellie, in the television series, Marlene claims that the doctor hoped to be able to replicate the chemical messenger that made Ellie immune.
== Gallery ==
TLOU HBO Nana with fungal tendrils.png|Nana infected with CBI.
Fungal tissue under bite wound.png|An examination of an early CBI victim found fungal tissue beneath a bite mark.
Ibu Ratna examines cordyceps sample.png|Ratna Pertiwi examines Cordyceps tendrils pulled from human victim.
Horde of infected in Boston streets.png|A mass of infected victims in .
== References ==
Category:HBO's The Last of Us miscellaneous