Mule Days on April, 2018: Grand Canyon Mule Trip?
Mule Days 2018.
There is only one trail closed from mule traffic for renovation, Kaibab Trail. The 2-3 years sounds correct for this trail, but no mule tours take this trail. The only mules that have gone down Kaibab are pack mules for supplying Phantom Ranch.
Unfortunately, this trail closure has put a lot of strain on the Bright Angel Trail, the primary trail for getting to Plateau Point and popular for getting to Phantom Ranch. So to alleviate some of the traffic, the Plateau Point Mule Tour has been stopped until further notice. Overnights to Phantom Ranch and an upcoming above rim mule ride are the only ones available (or soon to be available). When your response talks about checking in at Bright Angel for cancellations, it's most likely a standard e-mail response they send out or referring to the overnights at Phantom.
The only company authorized to provide mule trips is Xanterra. If you are going through a third party, try checking directly with Xanterra to get more accurate information.
Are these drug mules?
Mules normally run larger amounts and do it discretely. If there is a lot of traffic, and they do not stay long, they are probably users, going the the house to get their drugs.
Mule with chronic diarrhea?
If there was a heavy worm load, and the mule had a large population of encysted larvae in the walls of the intenstines, then a major kill off would cause the encysted larvae to emerge from the intestinal lining and enter the passageway. This can leave the walls of the intestine inflamed and bleeding, and unable to function normally. The inflammation can cause hyperactivity of the muscles that propell intestinal content through the tract, so that it is moved too rapidly for water to be absorbed out of it and it creates watery diarrhea. This also prevents absorption of needed nutrients, and can result in deadly electrolyte imbalance and dehydration. Garlic will do nothing to help the mule. Keep the mule well hydrated and call the vet for some advice over the phone, which costs nothing. Be prepared to tell the vet the name of the deworming agent that was used. In the meantime, feed only easily digested plain grass hay that is wetted and chopped. Purina Senior Feed pellets fed as a mash will also be easily digested and provide some fluids. You can add a tablespoon of salt to the feed, but the mule really should receive IV electrolytes if this is at all advanced. Anything fed orally is likely to be passed in the diarrhea and not absorbed.
I'd get the vet on the phone asap to see what he or she thinks.