Diseases

A disease is the manifestation of the malfunction of a person's body, associated with specific symptoms and usually caused by a biological agent like a virus or a genetic deformity. Several such illnesses have appeared in the One Piece series.

Scurvy
Scurvy is a disease caused by a lack of vitamin C, commonly experienced by pirates and other long-term sailors due to the lack of fresh food. Symptoms of scurvy include pale skin, teeth falling out, and the reopening of old wounds. The only known victim of the disease is Yosaku, though he recovered with Nami's help.

Scurvy can be treated by consuming a fruit juice, such as lime juice. Both the cause and cure of scurvy are well-known.

Five-Day Disease
Five-Day Disease is a zoonotic disease transmitted through the bite of a Kestia, which was a creature typical of ancient tropical forests. It was believed to be extinct, but it survived in Little Garden due to its prehistoric conditions. Symptoms of Five-Day Disease include exhaustion and sweating, sudden fainting and a high fever, and headaches. Internally, the disease causes heart, brain, and eventually full-body failure in the victim. The only known victim of this disease is Nami, who recovered with Dr. Kureha's help.

A cure for Five-Day Disease is known, and was something that Dr. Kureha was able to quickly make. The standard cure can completely eradicate the disease in ten days, but Dr. Kureha's version only takes three.

Diver's Disease
Diver's Disease (潜水病) is a disease suffered by divers who do not properly decompress when returning from the deep sea. Due to the decompression suffered by divers when rising from the bottom to the surface of the ocean, their blood is unable to remain in its soluble state and ends up creating air bubbles inside the body. These bubbles begin to expand in and out of the veins, damaging the bloodstream, muscles and joints.

Mont Blanc Cricket is the only known victim of the disease, when he repeatedly dived to look for the City of Gold and prove the innocence of his ancestor Mont Blanc Noland. However, a treatment is known, and Tony Tony Chopper successfully cured Cricket.

Tree Fever


Tree Fever is a lethal, highly contagious disease capable of affecting much of the vegetation in a given location. A person can contract this disease when consuming an infected product. The only known symptom is the appearance of dark spots on the body, and it has a mortality rate of 90%.

Victims of the disease include Seto and Chiya. However, a 100% effective vaccine made from Conine is known, allowing Seto to be cured.

Love Sickness


Love Sickness is a seemingly psychosomatic disease contracted by the empress of the Kuja tribe, when she falls in love with a man. Due to the psychological nature of the disease, the symptoms manifest according to the actions of the empress' love; when they attempt to leave, the empress suffers unbearable heart pain, but when they are together, she can receive a massive boost of strength. The disease manifests itself due to suppressed emotions, and if the empress continues suppressing her emotions, her health will continue to decline until their death; due to this, it has caused the deaths of many past empresses of the Kuja.

Victims of this disease have included Elder Nyon, Shakuyaku, and Boa Hancock, as well as many past empresses.

Amber Lead Syndrome


Amber Lead Syndrome is a non-contagious and hereditary pathology caused by the accumulation of Amber Lead in a person's body. Symptoms of the disease including graying of the skin and hair, body pain, and eventually death. Amber Lead Syndrome was mostly present in Flevance, where it spread to much of the population.

No cure for the Amber Lead Syndrome is currently known, with the exception of a manual surgery done with the Ope Ope no Mi; due to this, Trafalgar Law is the only known survivor of the disease. Non-canonically, this surgery has been described as going through every organ in the recipient's body and manually extracting all traces of Amber Lead; in Law's case, he had to extract his liver, collect the Amber Lead, and remove it using a scalpel.

Kiss-Kiss Germ


The Kiss-Kiss Germ is a disease utilized by the Germ Pirates in their attack on Dressrosa. Those infected by the disease are compelled to kiss those who are not infected uncontrollably. The spread of the disease is unknown, though it appears to be transmitted by the guns used by the Germ Pirates. Victims of the disease include various residents of Dressrosa, including Kyuin.

It is unknown if there is a cure.

Mummy


Mummy is a contagious artificial virus created by Queen and used as a weapon by the guards in Udon. Symptoms of the virus include heavy fever and bleeding; upon reaching the final stage of the virus, victims become dry and pruny, like a mummy. Following this, they become like zombies, and feel everlasting pain. It can be artificially spread through Excite Bullets or an Excite Shot, or naturally spread through contact with the infected.

Victims of the virus include the prisoners in Udon and Monkey D. Luffy; however, a cure was easily manufactured by Tony Tony Chopper, curing all the infected.

Ice Oni


Ice Oni is a contagious artificial virus created by Queen and used as a weapon during the Raid on Onigashima. The primary symptom of the virus is gradual ice growth over the victim's body, paired with a feeling of extreme cold. The ice takes on a demonic shape, forming a pair of horns and sharp fangs on the victim's head and mouth. When the ice finishes covering their body, the victim loses their sense of reasoning and enters a berserk state, attacking everyone around them; in this state, they also receive a boost in physical strength and durability due to an increase in muscle mass. Within an hour of the initial infection, the victim will die from the excess strain on their body.

Victims of this virus include various Pleasures and Waiters, many of the samurai participating in the Raid, Omasa, Tony Tony Chopper, and Hyogoro. A cure exists, developed by Queen as a safety measure, but he possesses the only known sample. Once Chopperphage was developed, it acted as a cure as well.

Chopperphage


Chopperphage is a benign artificial virus created by Tony Tony Chopper. It acts as a countervirus to Ice Oni, spreading through the air and curing any victims of Ice Oni that breath it in a matter of seconds.

Feminization Disease


Feminization Disease is a contagious artificial disease created by Doc Q using the Shiku Shiku no Mi. Its only known symptom is changing the sex of men, transforming them into women in a way similar to the Horu Horu no Mi. Notably, due to it being the result of a Devil Fruit ability, the disease can be cured using Haki; once someone cures themselves, their antibodies will spread in the same way as the disease, curing it for those around them as well.

Known victims of the disease include Trafalgar Law, Bepo, Shachi, Penguin, and other members of the Heart Pirates, though they were ultimately cured when Law overwhelmed the disease with Haki.

Sapphire Scales
Sapphire Scales is a rare and incurable disease that causes sapphire-like stones to grow on the victim's skin due to exposure to natural light, eventually leading to their death. It was contracted by Ginny and later her daughter, Jewelry Bonney. It is unknown how someone catches this disease, other than from it being spread.

Mondolin


Mondolin is a contagious febrile disease. Its primary symptoms are fever, weakness, sweating, and flushing of the face.

The only known contractor of the disease is Dr. Kureha, though she contracted it from a patient she was treating. The cure for the disease is well-known, and Chopper was able to quickly replicate it from a medical book.

South Blue Emperor Fever


South Blue Emperor Fever is a lethal, seemingly non-contagious, disease. While the full symptoms are unknown, the disease causes those infected with it to be bedridden for long periods of time.

200 years ago, this disease was considered incurable, though a cure has been developed since then, administered with a single injection. Alternatively, being in the vicinity of Pure Gold will completely negate all symptoms, temporarily returning the victim to full health. The only known contractor of the disease is Myskina Olga, who was cured by Chopper.

Notable Unknown Diseases and Associated Fatalities

 * Gol D. Roger at one point contracted a nameless, incurable disease around 28 years ago. Crocus, the Roger Pirates' doctor, was unable to do anything about his condition besides keeping Roger alive until he finished his quest for Laugh Tale. Roger in the end did not die to his disease, having let himself get caught by the Marines and executed soon after.
 * Banchina, Usopp's mother, died of an unknown disease that caused her to stay bedridden with a strong fever.
 * Yorki and several other members of the Rumbar Pirates suffered from an unknown disease during their travels, after spending time in a jungle. Symptoms of the disease include dark spots on the skin and general weakness. It is unknown if a cure for the disease is known, but it was at least unknown to the Rumbar Pirates' doctor. The symptoms and contraction of this disease are reminiscent of Five-Day Disease, but no explicit link has been defined.
 * Edward Newgate, because of his advanced age, was known to have been very ill during the Summit War of Marineford, which contributed to his eventual death at the hands of the Blackbeard Pirates and the Marines.
 * Gimlet, Senor Pink's infant son, died because of a fever.
 * Doflamingo and Rosinante's mother died of an unknown illness, which resulted from the unhygienic conditions her family were living in.
 * Vinsmoke Sora, Sanji's mother, died from the after-effects of an unknown drug she had taken in order to preserve her children's humanity.

Trivia

 * Tony Tony Chopper's dream is to become a doctor capable of curing any diseases.
 * Usopp often uses diseases as an excuse for his cowardice, usually calling them "Can't-get-on-this-island disease" or something alike.
 * Ironically, Usopp once claimed, alongside Luffy and Sanji, that he has never gotten sick before.