Understanding Mycoplasma Arthritis in KuneKunes
A Comprehensive Guide for AKKPS Breeders & Members
Written by AKKPS Member Amanda Carlisle of Carlisle Acres
Mycoplasma-related arthritis has become a topic of conversation among KuneKune breeders recently. Having accurate, clear, concise knowledge of the organism is important. While these organisms are common in swine worldwide, most herds experience only mild or occasional symptoms.
This guide provides breeders with clear, veterinary-supported information about Mycoplasma hyosynoviae and Mycoplasma hyorhinis — including symptoms, transmission, carrier status, management, and when testing may be helpful.
What Is Mycoplasma?
Mycoplasmas are a unique group of bacteria lacking a cell wall, making them resistant to some antibiotics and difficult to culture.
Two species are important in swine arthritis:
1. Mycoplasma hyosynoviae (M. hyo)
- Affects pigs 10+ weeks through adulthood
- Causes arthritis only
2. Mycoplasma hyorhinis (M. hyorhinis)
- Affects piglets 3–10 weeks
- Causes arthritis
- plus systemic inflammation (polyserositis)
- These organisms do not cross the placenta and do not cause
- congenital defects
- farrowing issues
- reproductive loss.
How Mycoplasma Spreads
Mycoplasma spreads through:
- Nose-to-nose contact
- Aerosol droplets at close range
- Licking/grooming
- Stress-related shedding from carrier animals
- Introduction of new pigs
- Commingling different age groups
Carrier pigs often shed the organism when stressed (transport, farrowing, temperature swings).
Carrier Status: How Long Do Pigs Carry It?
Mycoplasma hyosynoviae:
- Long-term carrier — months to years, often lifelong
- Lives in the tonsils
- Shedding increases during stress
Mycoplasma hyorhinis:
- Short-term carrier — weeks to a few months
- Common in young pigs
- usually cleared after infection
- Does not persist in adults long-term
- Carrier pigs appear perfectly healthy and raise normal litters.
All Possible Symptoms of Mycoplasma Arthritis
Mycoplasma hyosynoviae (Grower–Adult Arthritis)
Affects pigs 10 weeks and older, often after stress.
Primary symptoms
- Stiffness when rising (classic sign)
- Difficulty standing or reluctance to rise
- Shifting-leg lameness (lameness changes from one leg to another)
- Arthritis without visible swelling
- Pain when joints are flexed or manipulated
- Shortened stride or stilted gait
- Reluctance to walk long distances
- Mild weight loss or reduced activity (optional)
Less common symptoms
- Joint swelling (possible but not typical)
- Sitting on haunches or laying frequently
- Temporary inappetence due to discomfort
Symptoms you will NOT see
- Fever
- Cough
- Congenital issues
- Death in newborns or fetuses
Mycoplasma hyorhinis (Young Piglet Arthritis + Polyserositis)
Affects piglets 3–10 weeks, especially around weaning.
Primary symptoms
- Fever (often high)
- Depression / lethargy
- Sudden lameness
- Multiple swollen joints
- Painful movement, difficulty standing
- “Dog-sitting” posture due to discomfort
Systemic symptoms due to polyserositis
(M. hyorhinis can inflame body cavities, unlike M. hyosynoviae.)
- Increased breathing effort / shallow breathing
- Abdominal distension or guarding
- Pleural inflammation (pain when breathing)
- Pericarditis (inflamed heart lining)
- Peritonitis (inflamed abdominal lining)
Other possible signs
- Poor growth
- Reluctance to nurse or eat
- Generalized pain when handled
Diagnosis: Symptoms vs. Testing
Symptom-Based Diagnosis (Most Common and Practical)
Veterinarians often diagnose Mycoplasma arthritis based on:
- Age of affected pigs
- Symptoms (especially stiffness, fever, swelling)
- Herd history
- Response to treatment
This is preferred because:
- Testing can be slow
- PCR may detect carriers but not disease
- Culture is difficult with frequent false negatives
- Treatment is the same regardless of test result
- Early treatment greatly improves recovery
Testing Options
- There is no useful blood test for Mycoplasma.
- Helpful tests include:
- PCR from:
- Tonsils
- Deep nasal swabs
- Joint fluid
- Tissues at necropsy
- PCR confirms presence, not necessarily disease.
- CULTURE:
- Definitive but very difficult
- equires specialized labs.
- PCR from:
Treatment
Most pigs recover fully within days to weeks.
Antibiotics (vet-directed)
- Tylosin
- Lincomycin
- Tiamulin
- Tilmicosin (with caution and vet supervision)
Pain Management
- NSAIDs such as meloxicam or Banamine
- Improves comfort and mobility dramatically
Supportive Care
- Warm, dry bedding
- Reduced stress
- Easy access to feed and water
Prevention & Herd Management
- Reduce stress, especially during weaning or transport
- Quarantine new pigs for 2–4 weeks
- Avoid mixing age groups
- Maintain clean, dry housing
- Ensure good nutrition & parasite control
- Monitor for early signs in high-risk ages
- Work closely with a veterinarian when symptoms appear
How Common Is Mycoplasma Carrier Status in KuneKunes?
Is This Something Breeders Should Worry About?
Carrier status for Mycoplasma—especially Mycoplasma hyosynoviae—is extremely common in pigs worldwide, including KuneKunes.
In fact, in most swine populations:
- 40–70% of adult pigs carry M. hyosynoviae in their tonsils
- Many remain lifelong carriers
- Most never show clinical symptoms
- Most breeders never even know Mycoplasma is present
KuneKunes are not more or less prone to carrier status than other breeds. They simply behave like typical swine in regard to Mycoplasma colonization.
Mycoplasma - Is this something to worry about?
Generally, no. Carrier status is normal, expected, and usually harmless. Here’s why it’s rarely a concern:
1. Carriers appear completely healthy
A carrier pig:
- Acts normal
- Eats normally
- Breeds normally
- Farrows normally
- Raises healthy litters
There are no reproductive or long-term health consequences.
2. Mycoplasma only causes issues under specific conditions
Clinical arthritis generally appears when:
- Pigs are young (3–24 weeks)
- Stress levels are high
- New pigs are introduced
- Age groups are mixed
- Transport or weaning occurs
Adult carriers rarely, if ever, become symptomatic.
3. Once a herd has Mycoplasma, it tends to stabilize
This means:
- Piglets get exposed early
- They build immunity
- Outbreaks become mild or nonexistent over time
Most farms go years without ever noticing Mycoplasma is present.
4. Mycoplasma is not a sign of a poorly managed herd
This is important for AKKPS messaging.
Carrier status is:
- Not a hygiene issue
- Not a genetics issue
- Not a husbandry failure
- Not something that can realistically be “eliminated” in small herds
It is simply part of the microbial environment of swine.
What about Mycoplasma hyorhinis?
- This organism is very common in young pigs worldwide
- Most herds experience it at some point in the weaning age
- Adult pigs do not remain long-term carriers
- Symptoms, when they occur, are short-lived and usually in 3–10 week piglets
Again, not a herd-threatening organism.
Situations Where Breeders Might See Problems
While carrier status alone is not a concern, stress can trigger symptoms in susceptible pigs:
- Newly weaned piglets
- Pigs moving to new homes
- Transport stress
- Sudden temperature changes
- Poor ventilation
- Mixing unfamiliar pigs
Good management greatly reduces the likelihood of clinical disease.
Mycoplasma Myths vs. Facts
Clearing Up Common Misconceptions for KuneKune Breeders
Myth 1: “If a pig has Mycoplasma, the whole herd is sick.”
Fact:
Most herds carry Mycoplasma without showing symptoms.
Carrier pigs are healthy, raise normal litters, and live normal lives.
Myth 2: “Mycoplasma causes reproductive problems or birth defects.”
Fact:
Mycoplasma does not affect fertility, pregnancy, litter size, or fetal development.
It stays in the respiratory tract and joints—not the reproductive system.
Myth 3: “A piglet born with issues (like enlarged heart or weakness) must be from Mycoplasma.”
Fact:
Mycoplasma does not cross the placenta and does not cause congenital defects.
Piglet developmental issues come from unrelated causes.
Myth 4: “A healthy farm should be Mycoplasma-free.”
Fact:
Mycoplasma—especially M. hyosynoviae—is extremely common in swine worldwide.
Most farms, including commercial high-health herds, have carriers without ever seeing disease.
Myth 5: “Mycoplasma spreads because of poor management.”
Fact:
Mycoplasma spreads through normal pig interactions.
Good management reduces flare-ups, but carrier status itself is not a failure of care.
Myth 6: “If one pig shows stiffness or lameness, the entire herd is infected.”
Fact:
Only pigs in the susceptible age ranges usually show symptoms:
- 3–10 weeks → M. hyorhinis
- 10+ weeks → M. hyosynoviae
Adults rarely show clinical signs even if they are carriers.
Myth 7: “Mycoplasma always causes severe illness.”
Fact:
Most cases are mild and respond quickly to treatment.
Many carriers never show symptoms at all.
Myth 8: “Testing is necessary to confirm Mycoplasma before treating.”
Fact:
Veterinarians often diagnose Mycoplasma based on symptoms, age, and history.
Testing can be slow, expensive, or inconclusive—treatment is usually started based on clinical evaluation.
Myth 9: “Mycoplasma can be eliminated from a herd.”
Fact:
This is nearly impossible without depopulation.
Instead, herds become stable, and pigs develop natural immunity over time.
Myth 10: “Carrier pigs should be removed from a breeding program.”
Fact:
Carrier status is normal and has no effect on breeding quality, conformation, temperament, or litters.
Carrier pigs are still excellent breeders and producers.
Key Takeaways for AKKPS Breeders
- Mycoplasma is common in pigs and often mild.
- Most pigs exposed become immune and never show symptoms again.
- Carrier sows remain healthy and raise normal litters.
- M. hyosynoviae affects older pigs and causes arthritis only.
- M. hyorhinis affects young piglets and causes arthritis plus body-cavity inflammation.
- Blood tests are not useful; PCR and clinical signs guide diagnosis.
- Early treatment provides excellent recovery in most cases.
- Managing stress is the most important part of prevention.