The book begins with several pages of large-type text simulating a computer read-out, each mimicking a step in the authorization process to enter a Biosafety level 4 laboratory.
In the first chapter of The Hot Zone, the reader is introduced to Charles Monet, an expatriate Frenchman who lives at the base of Mount Elgon in western Kenya in 1979. An amateur naturalist, Monet decides to use his winter holiday for a camping trip to the national park on Mount Elgon. Monet invites one of his lovers from the village to go with him. On the second day of the trip, Monet and his friend explore Kitum Cave, a local tourist attraction and petrified rain forest that contains an array of crystals, as well as bats, insects, and mummified elephant corpses.
Seven days after the trip to Kitum Cave, Monet develops a severe headache. He decides to stay home from work, but the headache only becomes more intense and is soon joined by a backache. Three days after his headache begins, Monet spikes a fever and begins to vomit uncontrollably. His personality changes – he becomes sullen and resentful to his housekeeper – while his face becomes frozen in a mask-like state. When his eyeballs turn red and his skin takes on a yellowish shade, Monet’s housekeeper fears that he is turning into a zombie.
Several of Monet’s colleagues visit to see if he has recovered enough to return to work. When they see the state of his illness, his co-workers immediately drive him to a private hospital in Kisumu. However, the doctors at Kisumu are unable to diagnose the cause of Monet’s illness and recommend treatment at Nairobi Hospital, a short plane ride away. During the flight to Nairobi, Monet becomes increasingly sick and begins to vomit up blood. When the plane lands, Monet manages to take a taxi to the Nairobi Hospital before collapsing and bleeding out in the waiting room.
Dr. Shem Musoke of Nairobi Hospital is the first to arrive on the scene. After feeling for a pulse, his first step is to clear blood and debris from Monet’s mouth in order to insert a laryngoscope. With Dr. Musoke leaning just a few inches from Monet’s mouth, Monet suddenly vomits, spewing blood all over Dr. Musoke’s face and upper body. Monet then slips into a coma and dies in the early hours of the next morning. Despite an autopsy, the hospital staff is unable to identify the cause of his death.
Nine days after the death of Charles Monet, Dr. Musoke develops a severe backache and notices that his eyes are beginning to turn red. He first diagnoses himself with malaria and takes malaria pills and an antimalarial shot. When his skin begins to turn yellow, Dr. Musoke revises his diagnosis to typhoid fever and attempts to treat himself with antibiotics. With the continued progression of his illness, Dr. Musoke finally presents himself to his colleague, Dr. Antonia Bagshawe, who recommends exploratory surgery.
The surgeons are unable to identify the cause of Dr. Musoke’s illness but notice an alarming symptom: he will not stop bleeding. The case then falls under the purview of Dr. David Silverstein. Suspecting that Dr. Musoke is suffering from an unknown virus, Dr. Silverstein collects a sample of his patient’s blood serum and sends it to be tested at the National Institute of Virology in South Africa and the Centers for Disease Control in the United States.
Dr. Silverstein soon receives word from South Africa that the blood sample is positive for Marburg, an African virus that was first identified at a vaccine factory in Marburg, Germany in 1967. After an initial outbreak in a shipment of monkeys that arrived at the factory, the virus soon spread to the human population, killing one in four of those infected. It was later discovered that the infected monkeys had undergone only a basic visual inspection prior to being exported.
Based on this new information, Dr. Silverstein convinces the Nairobi health authorities to shut down the hospital and quarantine the 67 medical staff members who had interacted with either Monet or Musoke. However, none of the staff members develop the virus. After ten days of illness, Dr. Musoke begins the slow but steady process of recovery. Although he retains no memory of his time under the influence of the Marburg virus, samples of Musoke's blood are sent to laboratories across the world.
The opening of the book apes the levels of clearance one would have to go through to enter a Biosafety level 4 laboratory. This tactic highlights both the extraordinary safety measures one must take, plus the danger inherent in working with a deadly agent. By following her footsteps through each airlock, the reader is also placed in the shoes of Nancy Jaax, one of the book's protagonists, and will be able to empathize with her throughout the text.
From the outset, Preston presents the Marburg virus as a true antagonist of the narrative. Instead of describing the virus and its symptoms in strictly clinical terms, Preston employs the literary technique of personification as a way to immediately establish the virus’s role in the book. He writes, “Having destroyed its host, the hot agent is now coming out of every orifice, and is ‘trying’ to find a new host.” As a result of this technique, Preston is able to present the virus as being actively engaged in the destruction of Monet’s personality and physical body. This also helps Preston to transform a nonfiction work into a dramatic narrative with a clear delineation between its heroes (Nancy Jaax, Jerry Jaax, Gene Johnson, etc.) and its villains (Marburg, Ebola Zaire, Ebola Reston).
Preston’s graphic description of Monet’s symptoms and eventual death also set the stage for the operation at the Reston monkey facility in the second part of the book. In order for the reader to comprehend the potential magnitude of an outbreak in the United States, they must be familiar with the full power of the filovirus as a life form. Preston is not subtle in his word choices as Monet vomits and hemorrhages. Preston also elects to switch narrative perspective when Monet is traveling to Nairobi by plane. Instead of describing the scene with the detachment of third-person narration, Preston writes in the perspective of another passenger who can hear and smell every stage of Monet’s illness. This narrative shift brings Monet’s experience much closer to home for the reader.
When Charles Monet arrives at Nairobi Hospital and is treated by Dr. Shem Musoke, the reader is introduced to the theme of chance in the spread of filoviruses. Dr. Musoke seems to have the potential to be one of the heroes of the book: he is young, energetic, and dedicated to his patients, even to the point of staying by Monet’s bedside until his death. Yet, as a reward for his close attention to his patient, Dr. Musoke is himself infected with the virus and nearly dies. Preston makes it clear that the filoviruses select their victims indiscriminately, regardless of character, morality, or action. The Hot Zone is not a work of fiction, and, in reality, good people are infected and die, simply by random chance.
When he describes the initial outbreak of the Marburg virus in 1967, Preston again alludes to the unjust nature of the filoviruses. Just as Dr. Musoke is infected because of his concern for his patient, the workers in Marburg are infected because they work at a factory that creates preventative vaccines. In both cases, individuals are exposed to the viruses as a direct result of their actions in aid of others. This scenario serves as a foreshadowing to the work of Nancy Jaax, Gene Johnson, and other scientists, who place themselves in extreme danger for the sake of their research.
However, even as he demonstrates the danger of selflessness, Preston is careful to reveal that the Marburg outbreak is partially due to human error and negligence. The English veterinarian who inspects the monkeys en route to Germany only gives them a brief visual inspection. Moreover, the monkeys that are deemed to be “sick” are not actually destroyed but shipped to an isolated island at the order of the company owner. While Charles Monet’s exposure to Marburg can be attributed to chance, the original outbreak of the virus is the direct result of laziness and greed. In this brief scene, Preston alludes to his later argument about humans being partially, if not wholly, responsible for the emergence of these deadly hot agents.