By:  Margaret Wissman, DVM, DABVP

Bladder infections, properly called bacterial cystitis, can occur in monkeys. These infections often occur from bacteria ascending (going up) the urethra from the outside and ending up setting up residence in the urinary bladder. Rarely, a bladder infection may occur from bacteria in the bloodstream getting into the kidneys, and then the bladder.

As occurs with humans, bladder infections are more prevalent in females. This is thought to occur from the fact that females have a shorter urethra, so bacteria have an easier time making the trip to the bladder. Bladder infections can and do occur in males, but just not as frequently.

When a monkey has a bladder infection, several signs may be seen. It may urinate small amounts frequently, there may be blood (in the form of a clot or causing the urine to be pink or red-tinged), the vulva maybe inflamed, and the urine may have a strong odor. Because of the pain and burning involved in a bladder infection, the monkey may urinate in inappropriate places to try to get its owner’s attention, and it may rub its genitalia on surfaces or use its hands to rub the genitalia. The monkey may also drink more water. In some cases there may be just a drop or two of blood visible in the vulva or at the tip of the penis during urination. In some cases the monkey may actually act ill, not eating, acting depressed or sleeping more, but these are usually signs that the infection is spreading to the kidneys, which is much more serious. If a bladder infection is left untreated, the bacteria may ascend up the urethra to the kidneys. Kidney infections can be quite serious, resulting in a fever, toxins in the bloodstream, damage to the kidneys and other complications.

Bladder infections cause irritation to the bladder wall and urethra. This can cause urethra spasms, which cause increased frequency of urination and burning during urination. If repeated infections occur, or if an infection is left untreated, it may result in the bladder wall becoming thickened.

Diagnosis of the bladder infection can be simple. A urine sample is examined for the presence of several abnormalities. If possible, the urine sample should be procured mid-stream, but since monkeys are not always cooperative, often a sample from the floor, cage bottom or other surface may suffice. If possible, bring a fresh urine sample with you to the vet, placed in a clean, dry bottle or jar. If it will be a while before you get to the vet, the sample should be refrigerated. A urine sample from the floor will not be adequate for a bacterial culture, but it is useful for other tests.

If its not possible to bring a urine sample to the vet, your vet may need to sedate or anesthetize your monkey to get a sample, either by catheterization (inserting a sterile tube into the bladder) or by expression of the bladder (squeezing the bladder gently through the body wall to get a urine stream). Another method of urine collection is by a needle aspirate. The vet will prep the skin and then insert a needle attached to a syringe through the body wall and into the bladder. Urine is then drawn into the syringe for evaluation.

Testing of the urine is straightforward. Vets routinely diagnose and treat bladder infections in other species of animals, so there is no species difference, making this one disease that vets unfamiliar with primates should be able to deal with, no problem. The urine will be spun in a centrifuge to spin the sediment to the bottom of the tube. This sediment will be examined under the microscope for the presence of white blood cells, red blood cells, crystals, cells from the urinary tract and other debris. The liquid portion of the urine is examined with a dipstick to test for the presence of glucose (sugar), nitrites and other components.

Diabetics will often have sugar in the urine, and seem predisposed to bladder infections. So it is important for the vet to check the urine for sugar. Overweight monkeys may be predisposed to developing diabetes. Recurrent bladder infections are one sign of possible diabetes which should be checked by performing a blood glucose level.

Monkeys with bladder infections often have red and white blood cells in the urine. These may only be visible by microscopic examination of the urine, or pus and red cells may be visible to the naked eye. If the infection is caused by bacteria, then bacteria will be seen under the microscope as well. A sterile culture of the urine will reveal which type of bacteria is causing the problem and a sensitivity test will tell your vet which antibiotics are acceptable to use in treating the infection.

Crystals may indicate bladder stones, which are quite rare. Bladder stones may have bacteria in them, causing bladder infections to occur after treatment. These are usually diagnosed by radiographs (x-rays).

Treatment should be based on the culture results. If culturing the urine is not possible, the vet may decide to choose an antibiotic, based on what usually works for bladder infections. I usually have good success with Septra, Augmentin and Keflex. These antibiotics come from a pediatric suspension, and are flavored to be palatable, so most monkeys will accept them readily. Sometimes I will prescribe a medication to ease the straining until the antibiotics kick in.

For humans with bladder infections, its recommended that they drink a glass of water per day. Obviously, we cannot instruct our monkey patients to do so, but we must encourage them to drink fluids. Feeding moist fruits will get extra fluid into them. If they like fruit juice, give them that. I often recommend using a bit of salt on the food, to make them thirsty and encourage water consumption. Caffeine and certain foods may irritate the bladder. The urine should be acidified, and the vet may prescribe medication to do so. There actually is benefit to giving cranberry juice for bladder infections, since it will help acidify the urine,...however it will NOT cure bladder infections. It is important that you give your monkey the antibiotics for the preadministered. Also, a follow-up examination of the urine is recommended to ensure that the infection is entirely cleared up. If antibiotics are not given for the right length of time, the infection may occur after antibiotics are stopped.

There is a condition in humans, called interstitial cystitis, which mimics a bladder infection, but no bacteria are found on urinalysis. With this disease the urine contacts the bladder lining, burning it, since a protective coating is missing, resulting in severe pain, bladder wall thickening, cracking, and bleeding. I have not seen a reported case of IC in a non-human primate, but it may occur. If your monkey has recurrent symptoms of bladder infection, but no causative agent is found, then IC may be the culprit. There are some treatments available, but antibiotics will usually make the condition worse, since they burn the bladder tissue.

Bladder infection must be differentiated between other diseases that can cause bleeding and pus. Uterine infections, vaginitis, orchitis (inflammation of the testicles) or tumors may also cause symptoms similar to those seen with bladder infections.