Porcine Cystitis-Pyelonephritis Complex in Pigs

Porcine cystitis-pyelonephritis complex is a bacterial infection that starts in the lower urinary tract, especially the bladder, and can move upward into the kidneys. In pigs, this matters because kidney involvement can cause permanent damage, poor body condition, lower productivity, and in severe cases, sudden death.

The condition is seen most often in sows, particularly older breeding females. Actinobaculum suis is considered the primary pathogen, although other bacteria can also be involved. The infection is usually ascending, meaning bacteria enter through the lower urinary tract and then spread upward.

This is not a condition to watch at home for long. A pig with bloodstained urine, cloudy urine, reduced appetite, or weakness needs prompt veterinary attention. Early care gives your vet the best chance to limit kidney injury and guide treatment that fits the pig, the herd, and the budget.

The main cause is an ascending bacterial infection. Actinobaculum suis is the best-known pathogen in pigs, but other bacteria such as E. coli, Trueperella (Arcanobacterium) pyogenes, and some Streptococcus and Staphylococcus species may also be isolated. Once bacteria reach the bladder, they can inflame the lining and sometimes continue upward to the kidneys.

A. suis has several traits that make infection easier to sustain. It grows well in anaerobic conditions and can increase urine alkalinity by breaking down urea into ammonia. That higher urine pH supports bacterial growth and can encourage crystal formation, especially struvite, which may worsen irritation and help bacteria persist.

Management and environment play a big role. Risk factors include limited water access, more fecal contamination around the perineum, excessive weight gain, leg injuries that reduce normal movement, and housing or hygiene problems that reduce normal urination or increase bacterial exposure. Natural breeding has also been linked with higher risk than artificial insemination because boars can carry A. suis in the preputial cavity.

Your vet will start with the history, housing and breeding details, and a physical exam. In a live pig, a presumptive diagnosis is often based on frequent urination plus bloodstained or cloudy urine. Urine testing may show red blood cells, inflammatory cells, bacteria, crystals, and renal casts.

Confirming the cause can take extra planning because Actinobaculum suis is an obligate anaerobe. That means samples need careful collection and transport with minimal oxygen exposure. Your vet may recommend urine culture, tissue culture, or PCR when available, especially if herd-level decisions depend on identifying the organism.

If a pig dies or is euthanized, necropsy can be very helpful. Typical findings may include a thickened, inflamed bladder, exudate in the ureters, and kidney pelvic lesions with blood, pus, foul-smelling urine, ulceration, or papillary necrosis. In many farm settings, combining clinical signs with necropsy and targeted lab work gives the clearest answer.

Prevention focuses on lowering bacterial exposure and helping pigs urinate normally and often. Constant access to clean water is one of the most important steps. When water intake drops, urine becomes more concentrated and urinary abnormalities become more likely. Clean, well-designed housing that allows good manure removal also reduces contamination around the hind end and lower urinary tract.

Breeding and farrowing hygiene matter too. Good sanitation during breeding, parturition, and routine handling can reduce spread of urinary pathogens. In commercial settings, wider use of artificial insemination has been associated with lower incidence than natural breeding, likely because it reduces exposure to boar-carried A. suis.

Your vet may also discuss herd-level strategies such as dietary urine acidification, reviewing parity distribution, and culling chronically affected older sows. Prevention works best when it is practical and consistent. Small changes in water delivery, cleanliness, flooring, and breeding management can make a meaningful difference over time.