Mycoplasma ovipneumoniae in Goats
Detection of Mycoplasma ovipneumoniae in goats is becoming increasingly common in Australia. So, what is Mycoplasma ovipneumoniae, how does it cause disease and what can goat owners do to find out if their goats are infected or, more importantly, prevent their goats becoming infected.
Mycoplasmas are a type of bacteria.
Several different types of mycoplasmas infect Australian goats:
Mycoplasma ovipneumoniae - causes pneumonia, arthritis and keratoconjunctivitis
Mycoplasma conjunctivae - causes keratoconjunctivitis, pneumonia and arthritis
Mycoplasma putrefaciens - causes mastitis and arthritis
Mycoplasma ovis - causes anemia, jaundice and dark urine
Mycoplasma arginini - causes no clinical disease or mild respiratory disease
Mycoplasma ovipneumoniae infects the lungs of goats.
Researchers in Canada in the 1980s experimentally infected goats with Mycoplasma ovipneumoniae by endobronchial injection (1). Some, but not all, of the goats developed a fever and coughing. Infected goats had increased respiratory and heart rates compared to uninfected control goats. At necropsy, goats that had shown clinical signs had pneumonia and pleurisy. Some of the infected animals did not clear the mycoplasma and not all of them produced antibodies.
At the same time, other goats were infected with Mycoplasma arginini. These animals did not develop obvious clinical disease, apart from transient fevers, and did not develop lesions in their lungs within 14 days of infection.
The researchers concluded that Mycoplasma ovipneumoniae is pathogenic for goats, causing pneumonia and pleurisy, and that Mycoplasma arginini is not a significant primary respiratory pathogen in goats.
Infection with Mycoplasma ovipneumoniae also predisposes goats to secondary lung infection with other bacteria such as Mannheimia haemolytica and Pasteurella multocida that normally live in the nose and throat of goats without causing any harm. Once in the lung these bacteria grow and secrete toxins that cause inflammation and lung tissue destruction.
All breeds of goats are susceptible to infection with Mycoplasma ovipneumoniae. Infection persists in a herd in chronic carrier does and bucks, with infection passing from does to kids soon after birth. Does shed the bacteria from their nose and throat, as well as in their milk.
Infected does and bucks may show no outward signs of infection, or may be coughing, wheezing, have runny eyes, breathe heavily after exertion, or simply be found dead. Infected does also have an increased risk of mastitis.
Kids may begin showing signs of infection (wheezing, coughing, runny nose, runny eyes, difficulty suckling) from one to two months of age. Some kids may develop swelling of the carpal (knee) joints. Weaning, hot and dry or wet and cold weather, raised dust, summer storms and grain feeding are all stressful for kids, contributing to clinical outbreaks of disease.
Mycoplasma ovipneumoniae often enters an uninfected herd via chronic carrier bucks or does that are showing no outward signs of infection. It is also spread at shows and by fence line nose-to-nose contact with other goats and sheep.
Every goat herd should have an animal health plan that includes a biosecurity plan aimed at preventing Mycoplasma ovipneumoniae and other goat pathogens entering the herd. Animals that attend show and all new arrivals should be quarantined and tested prior to introduction into the herd. Ask suppliers about their pneumonia status. Check introduced goats for ear mites and treat if required. Do not feed colostrum sourced from other goat herds or from cattle to goat kids.
In the 1970s research in Australia indicted that nasal swabs could be a good way to monitor sheep and goats for respiratory pathogens (2). Today, PCR tests and new sample collection technologies make nasal swab monitoring even more useful.
For years culture techniques were considered the gold standard for detection of bacterial pathogens involved in infectious disease in animals. The advent of real-time hydrolysis probe PCR has made us re-think the gold standard for diagnosis of a range of animal diseases.
Diagnostic samples from goats are often contaminated from field collection, have undergone autolysis or bacterial overgrowth during transport to the laboratory, or are from animals that have chronic disease. This presents challenges that PCR can help overcome.
For highly fastidious and slow growing bacteria like Mycoplasma the benefits of PCR are obvious – cheaper, faster, and more reliable detection of outbreaks and shedding (3,4).
Testing goats for Mycoplasma ovipneumoniae can be arranged through one of my on-farm disease investigations. Knowing the cause of coughing and pneumonia in goats means an effective treatment program can be implemented. Without this information the wrong treatments may be given, delaying the animal's recovery.
When detected early, infection with Mycoplasma ovipneumoniae can be treated.
Please get in touch to arrange testing of your goats.
References
1. Experimental studies on the pathogenicity of Mycoplasma ovipneumoniae and Mycoplasma arginini for the respiratory tract of goats. Goltz, J P, et al. 1986, Canadian Journal of Veterinary Research, Vol. 50, pp. 59-67.
2. Isolation, propagation and characterization studies of an ovine Mycoplasma responsible for proliferative intersitial pneumonia. Carmichael, Leland E, et al. 1972, Cornell Vet, Vol. 62, pp. 654-579.
3. Use of a novel real-time PCR technique to monitor and quantitate Mycoplasma boivs infection in cattle herds with mastitis and respiratory disease. Sachse, Konrad, et al. 2010, The Veterinary Journal, Vol. 186, pp. 299-303.
4. A Real-Time PCR for Detection and Quantification of Mycoplasma ovipneumoniae. Yang, Falong, et al. 2014, Journal of Veterinary Medical Science, Vol. 76, pp. 1631-1634.