Gerbils are fairly healthy critters that rarely need medical attention. If your gerbil is sick, cold, listless, clicking, injured or distressed you should find a vet in your area that sees exotic pets.
Common signs of disease
Coat is fluffed up or puffy. Gerbil may be hunched with eyes pinched shut. Gerbil is cool to the touch. Gerbil wobbles or stumbles while walking. Gerbil makes clicking sound while breathing. Provide gerbils with moist food. Set up a warm spot in the cage for the gerbil an undertank heater for reptiles, heating blanket, or a 40 watt incandescent bulb work well.
I keep Nature Zone's Bearded Dragon Bites on hand at all times. This stuff has saved me over and over again with my gerbils. Its a moist food that is an appetite stimulant. I give it to weaning pups, seniors gerbils and even expectant mothers. I always give it to gerbils that are even a little under the weather. I also use it with senior gerbils with broken teeth that are having a hard time keeping their weight up. These dragon bites are basically treats, they are not a diet replacement, but they do help hydrate a sick gerbil
Critical Care by Oxbow is a liquid diet replacement. Its not especially suited to gerbils due to the high content of timothy hay. It does work. I usually recommend offering peanut butter, mashed banana, plain apple sauce, and plain unflavored oatmeal made with water. As moist food alternatives.
Gerbils are prone to seizures. There are two main types of seizures seen in gerbils.
Pup Seizures: Freeze, Twitch, and Glued to the Ground
Young pups can be overwhelmed by life and new experiences. Some especially sensitive gerbils may freeze up and twitch. The twitch may affect only the ears which may flick back. They may also rock or jerk back and forth with their ears. Gerbil pups may also freeze up, become overly warm, and slightly lethargic but will remain standing. Gerbil pups may also freeze up by spreading themselves onto the ground and trying to press themselves down onto the ground. Generally speaking if you try and roll a pup onto its side, it will roll back and resume its attempt at gluing itself to the ground. These behaviors are often seen in pups and most gerbils grow out of this behavior. If your gerbils is doing any of these, its best to just put them back in their cage in their hide and let them rest.
Some gerbils never outgrow their pup sensitivities. These gerbils are going to be prone to full blown seizures when over stimulated. They will lose all muscle control and will lay on their sides and twitch, kick, and may even roll around. Make sure there is nothing the gerbil can injure themselves with. There is not much you can do except to try and prevent them. Loud noises, flashing lights, handling, and cleaning their cage are the main triggers.
Gerbils with an URI, upper respiratory infection, may wheeze, crackle, or click when breathing. They often breath rapidly. URIs are typically seen in pups around weaning time. Senior gerbils (over 2.5 years) are also prone to it.
Diarrhea in gerbils is never good. There is a long, long list of diseases that can cause gastroenteritis. E. coli, salmonella, listeria, campylobacter are some super common causes. Diarrhea in gerbils is usually very contagious and can be deadly. Gerbils do not drink a lot of fluids and tend to dehydrate rapidly when they have diarrhea. Gerbils should immediately see a veterinarian if they have diarrhea. Do not wait. They may need a subdermal injection of fluids and will need antibiotics, followed by a round of probiotics. When gerbils have diarrhea you should wash your hands before and after handling the sick gerbil and its cage mates. You should also use a 2% bleach solution to sterilize their cage, bottle, wheel and toys.
Now the internet has drummed up some serious fear around Tyzzers being a death sentence. I've had Tyzzers rip through my kennel before and it was a very unpleasant experience. Tyzzers rapidly kills pups, seniors, and occasionally stressed mothers. It doesn't always cause illness or death in adult gerbils who are otherwise healthy. Most adults do not get sick or do show symptoms at all. Antibiotics should be given to all your gerbils, especially those that are not outwardly sick as they may be harboring Tyzzers. Tyzzers is fairly common in farm animals, especially cattle.
Gerbils who have a red nose have a sinus infection. Gerbils have sensitive noses and its easy for dust to irritate, obstruct, or block their sinuses. Most red noses should clear up in a week or two. If the hair around the nose starts to fall out or their skin becomes chapped or scabbed over they will need antibiotics. Gerbils rarely have true allergies to their bedding, but it is possible. If you're gerbil has chronic cases of red nose, you should consider switching to a different bedding. White beddings are known to cause reactions. Choosing beddings with low dust will also prevent dust from clogging up their sinuses. Kaytee Clean and Cozy Natural or crinkled kraft paper bedding like Eco-Bedding are hypoallergenic.
Common Health Problems in Senior Gerbils
Scent Gland Tumor
Pink growth on scent gland, may be smooth or look like a papilloma. These can be removed by surgery or frozen off at a vets office. If left alone they will continue to grow. The gerbil may chew on them. Once they are open they tend to have great difficulty healing and usually become infected. More common in older male gerbils.
I have previously used freeze off wart removers to slow the progression of the tumor. It can be an effective alternative if your gerbil is very old or unlikely to survive a surgery.
Malocclusion or Chipped Teeth
Older gerbils are prone to damaged teeth. They may lose the protective yellow enamel on their teeth which will cause the teeth to wear faster. The teeth may also begin to grow crooked and become overgrown. Occasionally a gerbil may break of chip a tooth. Gerbils will often lose weight rapidly if their teeth are damaged. Gerbils chew their nails and gerbils with bad teeth often have overly long toenails.
A vet can clip the teeth to keep them even. A vet should not need to put a gerbil under to clip the teeth. It can be done with a small pair of clipper. Gerbils teeth are small enough and do not need to be ground down like larger rabbits or guinea pigs. If you happen to live near me, I can clip teeth. You can schedule an appointment.
Older females may develop ovarian cysts. Often they rapidly gain weight in their abdomen. Often they can live a short time with the cysts. At some point the tumors may interfere with their quality of life.