Verdialization
Verdialization is the process in which otherwise non-verdial are colonized by, and eventually achieve homeostasis with, a Caudal lichen symbiote. Verdialized humanoids are considered verdial for many physiological purposes once verdialization is complete, thought this process is not irreversible and is not without health risks - including, potentially, death.
Transmission & Vectors
Verdialization is initiated by long-term exposure to environments or individuals harboring Caudal lichen fomites. Initially, the bodies of other mammals reject the fomites, producing an allergic response which may include running noses, itchy eyes, and other signs of a hay fever in those sensitive to airborne allergens. This usually does not rise to the level of anaphylaxis, though, in rare cases, individuals cannot enter the Petalcap Vale city limits due to the severity of their reaction.
Engaging in the somewhat taboo act of consuming Caudal lichen clippings greatly increases the risk of undergoing verdialization. Some individuals do this to cement their bonds with verdial spouses, while others do so out of an unusual fascination with verdial cultures or the process itself. In any case, a person who consumes a portion of a Caudal lichen symbiote faces a 10% chance of undergoing verdialization for each time the act is completed.
Causes
Over time, as affected individuals become acclimated to Caudal lichen fomites, their immune system stops being able to prevent the infiltration of lichen spores. The spores accomplish this via an unknown anti-immunogenic pathway. There is around a 1 in 20 chance of this happening to an individual for every year they spend regularly exposed to these fomites, with children being overall more susceptible. Once established, the Caudal lichen spores begin to grow, expanding into surrounding tissues by degrees and, via a poorly-understood process, begin to cause nearby cells to harbor chloroplasts. The growing lichen symbiote itself takes on the histological markers of its host organism, becoming indistinguishable by the body's defenses.
Symptoms
An individual undergoing verdialization may find themselves developing small lumps on the posterior surfaces of their body, from their lower calves all the way up to their head, across the scalp, and anywher else where hair tends to grow perfusely (i.e. beards). These may become itchy, though they are seldom outright painful. These are the places where the 'petals' of the growing Caudal lichen symbiote will eventually grow out of the body, hijacking the hair follicles as escape routes where possible. In rare cases, a patient may show signs of tumors in other places, as the growing symbiote can sometimes press against internal organs and body cavities; this part of the process, if occuring early enough, can sometimes be mistaken for cancer when the symbiote has not yet infiltrated the host's cutaneous tissues.
Treatment
If verdialization is not desired, a patient can be given strong anti-fungal medications to weaken - and possibly destroy - the growing symbiote. Doing so is ill-advised after a certain point, however, as the infiltration of the symbiote can cause deep, complex wound tracks prone to infection and reduced healing when it whithers away. Alternatively, if a patient is willing to take the risk and would like to voluntarily become a verdial, the Ghostleaf Foundation has recently begun to offer nutritional supplements and other drugs to maximize the possibility of a successful conversion.
Prognosis
In 90% of all cases of verdialization, if left untreated, the patient will become a verdial within 1-3 years of the beginning of the process. Around 5% take longer than this, particularly individuals with a strong immune response, in sun- or water-poor environments, or who take medical precautions against symbiotic rheumatism. Unfortunately, the remaining 5% of patients will suffer lethal infarcts and organ damage as part of the process, as the Caudal lichen, being unable to intelligently control its own growth, expands into parts of the body that cannot survive the disruptions it brings. Notably, these neophyte verdials almost always pass the condition on to any offspring they might give birth to; children born to verdials are always verdials at birth, despite the foreshortened course of the transformation.
Sequela
During the course of verdialization, some patients will experience chronic joint pain as the growing symbiote infiltrates the tissues between joints and begins growing beyond the host bodies' ability to adapt. This is an aquired form of symbiotic rheumatism, a disorder for which treatment regimes are available as of the year 10,000 AR.
Prevention
Those not wishing to become verdials can take certain precautions to reduce their risk of exposure to fomites during their stay in verdial-held spaces. Full-length clothing, gloves, and head coverings can reduce the amount of skin exposure to fomites, while dust masks and goggles can help to reduce mucous membrane exposure. It should be noted that these precautions are not necessary for short interactions with verdial-held environments (e.g. less than three consecutive months) and may be considered culturally inappropriate to undertake in such environments.
Cultural Reception
The process of verdializaiton has many of the same features of an acquired, chronic, communicable disease. While many non-verdial people experience a degree of body horror at the concept of being 'infested' with a foreign entity, others embrace it as a way of completely reworking their lives. The horror many feel at the prospect of verdialization has engendered discrimination against verdials among human and Rostran populations. Rostrans are more likely to accept the process due to prior cultural experiences revolving around the merging of two 'spirits,' as this is what is said to happen when one successfully executes a 'good' ritual sigil.
The ability of verdialization to spread among a population has forced the Manifold Conservation Society to debate their policies surrounding the maintenance of population diversity versus their mandate to preserve life in the Manifold Sky as a whole. People living in Bunker Primus - including verdials - will eventually all breed together, with most likely to become verdials due to the unique contaigion that is the Caudal lichen symbiote. Some see this as not a problem, as a purported beneficent government seeking to save the Manifold from itself should not stand in the way of social mingling and inter-racial love. Others see it as a dangerous path to a lack of genetic diversity, creating a monoculture where verdials have an increasingly dominant grip on MCS policy. This debate has become rancorous at times, with the famous serial killer the Midnight Griller taking the enforced diversity side of the debate to the logical extreme: burning, killing, and eating verdials in an attemt to reduce their numbers, a crime streak which became known as the Charred Chard murders .
This is a fascinating article. I really like the bit about cultural reception at the end. Charred Chard Murders got a weird chuckle out of me.