Cat influenza.
Two years ago my cat contracted influenza - It's different from human influenza in the way that it causes eye ulcers, permanently damages nose and throat lining, and stays with the cat its entire life after they get it. Some cats carry it without ever showing symptoms, for others it occasionally it flares up during periods of stress or when the immune system is weakened.
The day before yesterday my cat went missing for the entire day - Since he got old he normally comes in for feeding at least twice a day, and he never does this in winter when it's hard for him to hunt, so of course I regarded his absence as being unusual.
Yesterday morning after a thorough search of the garden, I found him lying in a ditch, in a nest of leaf litter, under a wooden panel behind my shed while having breathing difficulties with mucus streaming from his nose, presumably after spending the entire night in the rain there - He was dry, but cold. Sure enough his flu had resurfaced, but it had never before been as bad as this.
I did however manage to coax him up onto his feet and clean him up, he was still able to walk, and he was still strong enough to drink by himself. Getting him to the vets isn't ideal, I don't have a car, everyone I know nearby who owns one is on holiday, and the only way of getting him there is put a pet carrier on the back of my bike, which stresses the hell out of him each time I've had to do it in an emergency, so I decided to only take him if he refused food.
Cats don't eat if they can't smell. He wasn't eating his normal dry cat food (he has a whole wood nearby to hunt in and supplement his diet with natural prey), which worried me, so I mashed up some oily fish which he ate a little bit of. I made a little nest for him in a box with some old towels and a blanket which I managed to coax him into sleeping in. After following some advice on the internet, I bought him some tinned cat food with fish and some other supplies.
Fortunately he's been yumming up the fishy cat food even though it takes him a little while to eat, he spends most of his time sleeping and I've spent time away from work keeping an eye on him, making sure he's covered with the blanket and that he's continuing to eat and drink.
Apparently slippery elm powder is good for mucus linings, so I dissolved a small amount in some water which I fed to him through a syringe. I've also dripped some salt water onto his nose, which wasn't pleasant for him but it seems to have cleared up his airways a fair bit.
This morning I fed him a small amount of warm chicken soup through a syringe - He was surprisingly co-operative with me when I tried that. He seems to have recovered much of his strength and his behaviour is almost back to normal, he's eating dry cat food again, although he still spends most of his time asleep and still wheezes and coughs occasionally. I've gotta keep an eye on him for the next couple of days in case he gets a re-lapse, but nursing him back to health has been successful so far it seems.
TL;DNR:
Boring story about how my cat has flu and I can't get him to a vet easily. I spent time away from work to nurse him back to health with some home remedies. So far it's been successful.