Take it to a rodent vet. Or you could call or drop in to your nearest vet, and might get some help on medication or healthy eating tips for your rat. I have had a sick rat before and got some very helpful advice from my daily vet. Unfourtunetly it can be fateful but there is always a big chance of survival! Hopefull my help helped you about your sick or injured rat.
I'll assume you mean sick.
A sick rat should go to the vet. Most veterinary hospitals do not treat rats, however, so be sure to call ahead and find out if they have an exotics vet at the clinic you are calling.
A few good rules of thumb about visiting a vet for your rat - they should be comfortable handling your rat. They should be familiar with the different medications used for rats (ie. baytril, doxycycline, enrofloxacin, vibramycin, amoxicillin, cephalexin, azithromycin, clavamox, gentacin, gentamycin, metacam, etc).
Most rat illnesses can be treated with a course of antibiotics, typically given for 2-3 weeks, twice a day. It depends on the illness for what medication is prescribed.
A good source of rat health can be found in the related link.
You call them a veterinarian
a dog
a patient
Do you mean when you call on the phone? Of course not; that makes no sense at all.
A person sick in bed is typically referred to as being "bedridden."
either call animal control and they will take it or take it to the vet
yes the animals can get sick but the humans (us) cant
doctors
It depends on the level of formality. I think invalid is somewhat of an outdated term, more so constained to literature and other written text nowadays. However, depending on the context, I think it would not be impolilte as much as passé to call someone a sick person an invalid. (If you are looking for a word to substitute for the phrase 'a sick person,' though, invalid is probably the best word that exists) Hope this helps!
If he or she is sick,then the parish would call a priest to anoint him and pray for him for his healing.
A person who looks after. Aniomals in a zoo is called a zookeeper
Because if it went after a healthy animal than that animal could run faster than a weak are sick animal. I hope this helps if not sorry.