Altarian Encephalitis
A retrovirus that incorporated its DNA directly into the cells of its host. The virus can lie dormant for years, but activate without warning. Victims would be pyrexic and comatose and would suffer from widespread synaptic degradation. Long-term memory, usually from the moment of the infection, would be destroyed. 

Anchilles Fever
Deadly disease capable of spreading rapidly in a planetary population and causing widespread and painful deaths in the millions. 

Andronesian Encephalitis
A disease transmitted by airborne particles. 

Aphasia
Dysfunction of certain brain centers affecting the ability to communicate in a coherent manner. 

Aphasia Virus
Virus created by Bajoran scientist Dekon Elig, intended to be used as a terrorist weapon against the Cardassians. The disease organism would have been delivered through an aphasia device planted in a food replicator by the Bajoran underground. Once contracted, the virus would find its way to temporal lobes and disrupt normal communication processes, causing a type of aphasia. As the virus spread, it attacked the autonomic nervous system, causing a coma, then death. 

Arethian Flu
Viral disease. 

Atherosclerosis
A pathological condition in some humanoid species characterized by the hardening of the arteries and accompanied by the deposit of fat in the inner arterial walls.

Barclay's Protomorphosis Syndrome
An intron virus that causes humanoids and other animals to develop structural and behavioral characteristics of earlier evolutionary forms. 

Bendii Syndrome 
Rare illness that sometimes affects Vulcans over the age of 200. The disease is characterized by gradual loss of emotional control; victims exhibit sudden bursts of emotion and irrational anger. 

Biomimetic Fluctuation 
Medical reading in Founders that are indicative of dangerous instability of the morphogenic matrix. 

Blight
The name given by the natives of the Teplan system to the disease that they were infected with by the Jem'Hadar as an example to all who defied the Dominion. Everyone there is born with it. In the asymptomatic stage, the victim has blue lesions on the face and body, which turn red with the onset of the terminal stage, known as Quickening; death soon follows. 

Bonnayan-Hashimoto Syndrome
Not genetic in origin, the syndrome is activated by a random mutation. It affects humans. The condition remains dormant until until approximately 35-40 years of age. The onset of symptoms include a gradual loss of motor skills and occasional mental confusion - leading to a rapid neuro-muscular degeneration, loss of cognitive abilities ending in a total neural depletion, which is fatal. Some medications have been known to delay the onset of symptoms, there is no known cure. 

Cartalian Fever
A deadly viral plague. 

Coleibric Hemorrhage
A fatal condition in Cardassian physiology. 

Cytotoxic Shock
Prostration of bodily function caused by high levels of cytotoxins. 

Darnay's Disease
A deadly ailment that attacks the brain and nervous system of its victims. 

Dermal Dysplasia 
Skin disorder caused by an overexposure of the epidermis to hazardous levels of thermal and ultraviolet radiation. 

Dorek Syndrome
A very rare and incurable disease that afflicts one out of every five million Ferengi. 

Forrester-Trent Syndrome
Degenerative neurological disorder. It is very rare, but if left untreated, can result in paralysis and even death. The syndrome is usually hereditary but can be activated by a random mutation. A neurostabilization regimen can stabilize or reverse the disease. 

Hemocythemia
Condition in which intracellular pressure is unstable. This condition is also called Hemocythemic imbalance. It is treated with osmotic pressure therapy. 

Hesperan Thumping Cough
A flu-like affliction. 

Holodiction
Contraction for holodeck addiction. A psychological condition where an individual becomes so caught up in holographic simulations that the real world becomes unimportant. 

HTDS
Holotransference Dementia Syndrome. Medical condition in which a person becomes so disoriented within a holographic simulation that they lose their sense of identity and start to think that they are part of the program. 

Hyper-REM
Abnormal neurological condition during sleep. 

Hyperacceleration
Biochemical condition that plagued the people of planet Scalos due to radiation poisoning of their water supply. Hyperacceleration of biological processes caused an individual so affected to experience one second as if it were an entire hour. Outsiders who were accelerated, quickly burned out, dying in a very short period to time due to cell damage. 

Hypochondria
Condition which causes the sufferer to imagine they have various other medical conditions. 

Iresine Syndrome
A very rare neurological disorder in humanoids characterized by a peculiar electropathic signature in the thalamus, and a severely decreased histamine count. Victims of the disorder, first identified in the 23rd century, would fall suddenly into a coma for approximately 72 hours. Diagnosis could be confused by the presence of any of 22 different substances that left electropathic residue resembling that of this disorder. 

Irumodic Syndrome
Degenerative disorder that causes progressive deterioration of the synaptic pathways. The disease can cause senility and eventually death. Treatment of choice for the disorder was peridaxon, though this was simply palliative; no cure existed. 

Iverson's Disease
A chronic disease that causes fatal degeneration of muscular functions in humans. Iverson's disease does not however, impair mental functions. 

Kalla-Nohra Syndrome
Pulmonary disease found only in those who survived the mining accident at Gallitep. 

Lacunar Amnesia 
Type of amnesia that occurs when a patient witnesses an act of violence so terrible that the patient rejects the reality of the situation. 

Levodian Flu
Disease which normally lasts for 29 hours. Symptoms are similar to Earth flu. 

Memory Virus
Organism which thrives on peptides generated by a hosts brain. It avoids the bodies immune systems by disguising itself as an engram. 

Mendakan Pox
Disease characterised by skin mottling. 

Morphogenic Virus
A virus engineered by Section 31 and planted in Odo with the intent of killing the Founders who link with him. In 2372, when Odo was at Starfleet Medical for an examination, he was unknowingly given the virus, but it did not manifest itself until three years later. The main symptom is a decreasing ability to shapeshift, accompanied by pain and peeling skin; the progress is accelerated by frequent shapeshifting and in the final stage of the disease, the Changeling cannot revert back to liquid state at all and die in a solid form. The cure for the disease contains a nucleotide marking sequence consisting of Adanine, Asporadine, Lytastolanine and Radanine.

Neural Depletion 
Complete loss of electrochemical energy of a humanoid brain, resulting in the death of the victim. 

Neural Metaphasic Shock
A potentially fatal failure of the neurological system in humanoids. 

Neurochemical Imbalance
A serious condition which arises in Vulcans during Pon Farr. 

Neuroleptic Shock
A neurological disturbance in which cortical functions of the brain's synaptic pathways are disrupted. This can result in a state similar to coma without the usual biochemical markers. 

Orkett's Disease
Viral sickness which swept through the Bajoran work camps during the Cardassian occupation, killing thousands of children. 

Phage
Disease which consumes the body, requiring replacement of major portions from other sources. The initial stage of the infection causes intense pain. The Phage was eventually cured by the Think Tank. 

Phyrox Plague
The population of Cor Caroli V suffered an outbreak of this disease in 2366. It was contained with the help of the Enterprise-D. Starfleet Command classified the outbreak as secret. 

Plasma Plague
A group of deadly virus types. An unclassified but extremely virulent strain of plasma plague threatened the densely populated Rachelis system in 2365. 

Pottrik's Syndrome
Disease which afflicts Cardassians. Very similar to Kalla-Nohra syndrome. 

Progeria
A rare genetic disorder which causes Humanoid children to age extremely fast. It was eradicated by medical science around 2374. 

Psi 2000 Virus 
A water based disease organism originally found on the planet Psi 2000 in 2266. 
This virus infected members of the Federation science team stationed on that planet, causing suppression of their inhibitions, and ultimately their deaths. 

Radiation Poisoning
Damage to the body produced by exposure to high levels of any type of damaging radiation. 

Rigelian Fever 
Deadly disease resembling bubonic plague that infected the Enterprise crew in 2269, necessitating that a landing party beam down to the planetoid Holbert 917-G in search of the antidote, ryetalyn. 

Rop'nGor 
A disease that sometimes affects Klingon children, somewhat akin to terrestrial measles. 

Rudellian Plague
Disease which the Cardassian colony on Pentath III suffered from in 2372. 

Rugalan Fever
Deadly disease causes deep comas in Trills. 

Rushton Infection
Rushton Infection killed Jeremy Astor's father in 2371. 

Sakuro's Disease 
An extremely rare disease contracted by Commissioner Nancy Hedford which can cause intense fever, weakness, and death if not treated. 

Somatophysical Failure 
In humanoid physiology, the collapse of all bodily systems. 

Stockholm Syndrome
In psychology, the tendency for hostages to sympathize with their captors after extended captivity. 

Symbalene Blood Burn 
Virulent disease that can rapidly kill a large number of people in a very short period of time. 

Synthococcus novae 
Bacillus strain organism, a by-product of modern technology. Although treatable, the deadly bacillus was regarded as a significant health hazard. 

Tahiti Syndrome 
Twentieth century term or a human longing for a peaceful, idyllic natural setting when suffering from the stresses of modern life. 

Telurian Plague
Disease which was still incurable in the 2360s. 

Temecklian Virus
Virus which broke out on Bajor in 2372. 

Temporal Narcosis 
Delirium produced by exposure to a temporal disturbance. 

Teplan Blight
Viral disease which was endemic to a planet in the Teplan system, located in the Gamma Quadrant. It was introduced in 2371 by the Jem'Hadar as punishment for the planet having resisted Dominion control. 

Terellian Death Syndrome
Disease which causes dizziness, blurred vision, palpitations, and a stinging in the lower spine. It causes cellular decay which can be reversed if caught early enough. 

Terrellian Plague
A dangerous disease. After Neelix served 'Rodeo Red's Red Hot Rootin Tootin Chilli', he thought his customers might be suffering from this plague. Fortunately, it turned out to be a case of heartburn. 

Thelusian Flu 
An exotic but harmless rhinovirus. 

Torothka Virus
Disease whose symptoms include stomach cramps and a skin rash. 

Transporter Psychosis 
Rare medical disorder caused by a breakdown of neurochemical molecules during transport. Transporter psychosis was first diagnosed in 2209 by researchers on the planet Delinia II. The condition affected the body's motor functions, as well as autonomic systems and higher brain functions. Victims were found to suffer from paranoid delusions, multi-infarct dementia, tactile and visual hallucinations, and psychogenic hysteria. Peripheral symptoms included sleeplessness, accelerated heart rate, myopia, muscular spasms, and dehydration. The problem was eliminated around 2319 with the development of the multiplex pattern buffer. 

Transporter Shock
Phenomenon which causes a person to experience dizziness, headaches and disorientation during transport by a malfunctioning system. 

Tuvan SyndromeA degenerative, incurable neurological disease which affects mainly Vulcans, Romulans, and Rigellians. In the very early stages, the patient's eyelids are slightly displaced, facial muscles are weakened, and respiration is irregular. Loss of motor skills occurs in 10-15 years; life expectancy is 20-25 years. In less than 5% of cases, the disease can accelerate without warning.

Vegan Choriomeningitis 
Rare and deadly disease. The symptoms include high fever, pain in the extremities, delirium, and death if not treated within 24 hours. 

Xenopolycythemia 
Disease characterized by an abnormal proliferation of red blood cells causing varied symptoms including weakness, fatigue, enlarged spleen, and pain in the extremities.

Yarmin Fel Syndrome
A terminal illness affecting Cardassians; it attacks the digestive tract, circulatory and respiratory systems, and cartilaginous tissues. It can be treated with hexagen therapy or neuro-regeneration procedures, but there is apparently no cure. Sufferers experience great pain. Disease treated by the use of Hexadrin.

Zanthi Fever
A virus affecting the empathic abilities of "mature" Betazoids. It causes brief, intense headaches, during which the sufferer unconsciously projects his or her emotions onto others nearby, provided those emotions already exist in those others subconsciously.  Fortunately, the sufferer is easily cured with a simple wide-spectrum antibiotic, and the effects on other people wear off in a day or two.