Several weeks have passed...
Professor Birch's research into the Pokemon monovirus had since made headlines, with new details on how it manifests and how it's transmitted. Several tests on captive leucistic Pokemon and their Trainers have proven the theory that the virus was carried from Region to Region by humans. The virus would lay dormant in a human host until it was transmitted by various means to the Pokemon; including air and contact transmission. Trainers who were injured during their journey were more susceptible to contracting and transmitting the infection and could even pass it along to other Trainers.
Those infected Trainers would transmit it to their Pokemon, and since the virus had an incubation of a few weeks, it could be transmitted to other Pokemon through battle without the infected Pokemon even showing any signs of the disease. The long incubation period allowed for disease transmission without the Trainers even noticing any infection, and Pokemon Centers were not yet equipped to detect the disease in its earliest stages.
Many Trainers who had captured these so-called Monochrome Pokemon were not yet aware of the virility of the disease, and they had watched their very teams become infected. The signs started off small, with just small patches losing pigment. Depending on the immunity of the Pokemon, some succumbed to the virus quicker than others, and Trainers in many Regions were shocked to see their entire team turn white.
As shocking as the disease was, it wasn't deadly. Their Pokemon performed normally, save for some slight increase in aggression, which varied from Pokemon to Pokemon. Within some circles, these infected Pokemon became prized by collectors, much in the same was as Shiny Pokemon. However, Birch cautioned on trying to avoid disease transmission and urged Trainers to wash frequently and remove infected Pokemon from their teams.
As Birch and his team looked for a cure, another new threat had arisen. Team Fauna came into power soon after the public announcement of the monovirus, claiming that it was a mutation of a simple skin condition. They claimed that Birch's research was causing more harm than good and pointed out that with the announcement of the disease, the prevalence of it skyrocketed. Monochrome Pokemon were popping up everywhere and Team Fauna claimed that Trainers were purposely spreading the condition.
Team Fauna decried Birch's research, claiming that his search for a cure was harming Monochrome and normal Pokemon. Members had lobbied for public access airtime where they discussed the horrors happening in Birch's lab, while field agents handed out propaganda and similar literature. The Petalburg Pokemon Center was raided by ecoterrorists and was forced to close for repairs. Trainers were accosted by Team Fauna field agents and many of them ended up joining the organization.
Hoenn was overrun with Team Fauna activity, and their teachings had a large majority of the public in a tight grip. With fewer visiting Trainers, it appears that they may achieve a victory that would make Ghetsis proud...