Todayโs path rounds are on ๐ฆ๐ฒ๐๐จ๐ฉ๐ฅ๐๐ฌ๐ฆ๐จ๐ฌ๐ข๐ฌ!
๐๐ก๐๐ญ ๐ข๐ฌ ๐ข๐ญ?
๐๐ฒ๐๐จ๐ฉ๐ฅ๐๐ฌ๐ฆ๐จ๐ฌ๐ข๐ฌ is caused by ๐๐ฒ๐๐จ๐ฉ๐ฅ๐๐ฌ๐ฆ๐ species, and today we will specifically talk about ๐๐ฒ๐๐จ๐ฉ๐ฅ๐๐ฌ๐ฆ๐ ๐๐จ๐ฏ๐ข๐ฌ. Mycoplasmas are a specific type of bacteria that lack a cell wall.
๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?
We see this bacteria primarily in feedlot cattle.
๐๐ก๐๐ญ ๐๐๐ฎ๐ฌ๐๐ฌ ๐ข๐ญ?
Mycoplasma bovis is a normal bacterial flora found in the respiratory tract of cattle, but can also be transmitted by direct contact with other cattle or inhalation of the bacteria. Once in the respiratory tract, the bacteria induces ๐๐ฉ๐จ๐ฉ๐ญ๐จ๐ฌ๐ข๐ฌ (programmed cell death) in the immune cells that target it, allowing it to evade the immune system. From there, it sets up shop in the lungs, causing a pneumonia. It can also invade into the bloodstream and cause a ๐๐๐๐ญ๐๐ซ๐๐ฆ๐ข๐ (bacteria in the bloodstream) that leads to bacteria gaining access to the joints, middle ear, mammary gland, etc.
๐๐ก๐ฒ ๐ข๐ฌ ๐ญ๐ก๐ข๐ฌ ๐ ๐ฉ๐ซ๐จ๐๐ฅ๐๐ฆ?
Wherever this bacteria sets up shop, it causes ๐๐๐ฌ๐๐จ๐ฎ๐ฌ ๐ง๐๐๐ซ๐จ๐ฌ๐ข๐ฌ. Necrosis is cell death, and caseous means โcheese-likeโ, so when you put them together, you get cheese-like cell death. What this actually looks like is very crumbly, yellow to white accumulations of dead cells in the affected organ. These caseous foci can affect so much of the organ that it compromises its function. In the case of pneumonia, this can cause significant respiratory distress in these animals.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐๐ข๐๐ ๐ง๐จ๐ฌ๐๐?
Mycoplasma bovis can be diagnosed based on bacterial culture of caseous lesions, or ๐๐๐ to identify bacterial DNA.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ญ๐ซ๐๐๐ญ๐๐?
Unfortunately, the severity of these lesions often make this disease difficult to treat by the time it is diagnosed, and very few cases will respond to antibiotic therapy. Therefore, these animals are often euthanized.
๐๐ก๐จ๐ญ๐จ๐ฌ
1-3) Examples of lungs with Mycoplasma bovis. It can also cause a ๐๐ข๐๐ซ๐ข๐ง๐จ๐ฎ๐ฌ ๐ฉ๐ฅ๐๐ฎ๐ซ๐ข๐ญ๐ข๐ฌ, or ๐๐ข๐๐ซ๐ข๐ง (major clotting protein) on the surface of the lungs.
4) An example of ๐๐ข๐๐ซ๐ข๐ง๐จ๐ฎ๐ฌ ๐ฉ๐๐ซ๐ข๐๐๐ซ๐๐ข๐ญ๐ข๐ฌ, a similar situation but involving the sac around the heart.
5) A joint filled with pus from Mycoplasma infection.
6) An example of caseous necrosis in a bone!
๐๐จ๐ฎ๐ซ๐๐๐ฌ
Maxie, G. Jubb, Kennedy and Palmerโs Pathology of Domestic Animals, Volume 2. Sixth Edition.
Campbell J. Bacterial Pneumonia in Cattle. Merck Veterinary Manual 2016.
Photos 1-2, 4-6 ยฉ University of Calgary Diagnostic Services Unit.
Photo 3 ยฉ Noahโs Arkive contributor OโToole licensed under CC BY-SA 4.0.
