Panama is not presented as a fully described setting but as a decisive location in Robert Neville’s past. Its importance lies in the way wartime experience continues to shape his body, habits, memories, and theory of survival long after the plague has transformed the world around him.

Wartime Imprint

Robert Neville acquired the habit of sleeping in pajama bottoms without a pajama top while stationed in Panama during the war. The habit survives into his solitary life, becoming a small physical remnant of an earlier existence. His body also bears a more conspicuous trace of that period: an ornate cross tattooed on his chest one night in Panama while he was drunk. Looking at it in the bathroom mirror, he regards his younger self as foolish, yet he allows that the cross may have saved his life. The tattoo therefore occupies an ambiguous position between drunken impulse, religious symbol, and possible protection.

The Vampire-Bat Bite

Panama is also the setting of the event Robert Neville identifies as the probable source of his immunity. While he was stationed there, a vampire bat bit him. He killed the bat, but could not establish whether it had previously attacked anyone else or whether he was its first human victim. His explanation remains a theory rather than a proven conclusion: the bat may have encountered a true vampire and acquired the vampiris germ, which then altered its feeding behavior so that it sought human rather than animal blood.

According to Robert Neville’s account, the germ was weakened in some way while passing through the bat’s system. It made him terribly ill but did not kill him, and his body consequently developed an immunity. When Ruth asks why they are immune, he can explain his own case only tentatively and cannot account for hers. Panama thus provides a possible biological origin for his resistance, while also emphasizing the limits of his knowledge: the place supplies the crucial incident, but not a complete scientific proof.

Memory and Survival

The Panama experience is woven into Robert Neville’s later attempt to understand vampirism scientifically. He studies disease transmission, vectors, bacterial attack, and the body’s defenses, and his recollection of the bat gives those investigations a personal foundation. The broader medical evidence includes the role of flies and mosquitoes in mechanically disseminating bacterial diseases, while his eventual recognition that bacteria can mutate overturns the confidence of a fixed explanation. Panama’s bite is therefore both a clue and a reminder that infection changes as it passes through different organisms.

The location also contrasts with the devastated present. In the house, Robert Neville is alone, drinks heavily, and forces himself through routines of hygiene, food gathering, and defense. His isolation makes old habits and bodily marks carry an unusual burden: Panama is no longer merely a place where he served during the war, but one of the few surviving coordinates in a life stripped of ordinary social continuity. Even his tattoo becomes part of a private archive of the person he was before Virginia Neville’s death, Kathy Neville’s loss, and the plague’s remaking of human society.

Narrative Significance

Panama connects personal memory to biological causation. The cross tattoo suggests the persistence of older religious and wartime meanings, while the vampire-bat bite points toward the rational investigation that defines Robert Neville’s later struggle. Neither explanation is sufficient by itself. The cross may have seemed protective, but his survival is more plausibly tied to an altered infection; the bite may explain immunity, but the mutation of bacteria shows that no single past event can permanently settle the future.

As a recalled location, Panama also gives Robert Neville’s survival a history before his house became a fortress. It marks the point at which an accidental encounter with an infected animal may have separated him from the majority of humanity. The place’s decisive narrative function is consequently retrospective: Panama helps explain why Robert Neville remains alive, why he can study the plague from outside its ordinary effects, and why his scientific understanding must remain provisional even when it changes the meaning of the entire world.