Plagues of Equestria

It had been about a week since The Haze began to spread throughout Equestria, the sickeningly thick orange fog growing from the remains of the Golden Oak Library, slowly crawling out and spreading to cover nearly the entire town in a matter of hours. Many avoided it at all costs, some were lucky, but most of Ponyville's population couldn't get out of it in time.

At first, very few thought anything of it; other than some minor skin irritation, it didn't have any immediately harmful effects. However after about half a day the ponies that breathed the fog began to fall ill, and by the first night of the fog's consumption of Ponyville, half the town was in the hospital.

Rainbow Dash noticed the fog and the illness that came with it, and wasted no time rushing to Canterlot, knowing Luna, Celestia, and Twilight would be there for an important meeting. She never saw just how terrible the infection became, not even when she returned with Twilight. In fact, the entire town seemed empty, as if they had all disappeared over that short time period. Twilight looked around uneasily, trying to get a gauge on the situation despite having almost none of the information.

"Creepy," Rainbow Dash broke the silence with her observation, "just a few days ago there was a fog so thick you couldn't see your own hoof in front of you, and the townsponies were all sick as dogs. Never thought I'd be outrun by a bunch of bedridden ponies." Her joke was almost completely ignored by Twilight, who took a few steps forward and examined a strange stain on a nearby wall; a thick, red splatter roughly the size of a pumpkin. She examined it, looking at the edges, before letting out a shaky sigh.

"Projectile vomiting, appears to be 90% bl-" she winced as her stomach churned at the suddenly noticeable stench of sick, she pulled away and covered her mouth with her wing before gulping. "blood... the rest is bile." Rainbow Dash shuddered at the thought of somepony throwing up that much blood, then looked around to see if she could spot any more suspicious stains.

"I should do a flyover of the town, see if anypony's okay." She half suggested, not even waiting for Twilight to respond as she darted up into the sky and did a quick scan over the town, then another, and another. She kept her eyes peeled but couldn't see anypony or anything that would answer the litany of questions the mares had.

"RAINBOW!" Twilight appeared next to Dash, startling her with her sudden scolding. "Stick with me please, we have no idea what's going on and I don't want anything catching you off guard." She let out a sigh she didn't know she was holding as she began to scan the ground. Rainbow Dash studied Twilight's expression, which seemed almost as if she regretted something, maybe not getting here fast enough? Twilight shook her head and met Rainbow's eyes. "Sick ponies don't just get up and leave town en masse, so my guess is a self-imposed lock-down. Come on, we gotta get to Ponyville General right away."