Things have been grim this year. Pandemic. No toilet paper in the stores. Being afraid to even go in said stores. Losing my little old Mimi.
I've decided to take the blog in a new direction. A bit of an experiment, just to see how it works. This is nothing new--CircusK9 has evolved more than once since I started it lo these dozen years ago.
I want to talk more about my job. I love my job. Despite the inherent ick factor that some people might have about the subject, my job provides me with an endless stream of absurd and interesting tales.
Like this one. I have developed a good working relationship with a clinic in SW Arkansas. This three-vet practice sees all species, and they send most of their necropsy cases to the lab. Because of the distance from their clinic to Little Rock, and because they are not on the route of one of our regular couriers, the vets often conduct field necropsies of production animals and send us a "box of parts" instead of the entire cow. Cheaper and faster.
One of the vets has been working with a beef cow-calf operation for some weeks that is having a big problem with conjunctivitis in the herd. The usual bacteria responsible for this is Moraxella bovis. That's the one you learn about in vet school. But that's not what they got back from swab samples. They got a species of Mycoplasma. They started to treat the conjunctivitis but some of the cows began dying from respiratory disease.
Cows are prey animals and have an amazing capacity for hiding respiratory disease until things become pretty disastrous in there. I've opened up cows to find 80% or more of their lungs full of pus and bacteria, and heart and lungs stuck to each other and the body wall with expansive fibrin adhesions. This is not good. Most vets who work with these animals, including me, suspect that cows harbor subclinical bacterial pneumonias pretty much all the time, and are just waiting for some stressor--transportation, parturition, change in weather, change in feed--to cross that line into severe respiratory disease.
So my friend sent me two boxes of parts from two cows from the conjunctivitis herd. He also sent some horrifying pictures of the conjunctivitis--I will spare you. I never really got anything definitive from the parts other than confirming that it was a bacterial pneumonia. He kept calling me to talk about this Mycoplasma they had isolated from the eyes, not Moraxella. It was a species I had not heard of, and I initially thought I just wasn't understanding him clearly. He often calls me when he's in a windy field standing over a dead cow so there is lots of background noise.
See, Mycoplasma bovis is a common culprit in bovine respiratory disease. Mycoplasmas are special bacteria--they don't have cell walls. They like to form microabscesses which are very difficult to treat. In fact, cows with Mycoplasma pneumonia are often not treated (they are culled). The lungs my vet friend sent to me did not look like Mycoplasma lungs. They looked like Mannheimia or Pasteurella lungs. But we failed to culture those bacteria. And you can't really culture Mycoplasma. We rely on PCR tests to identify that one. But I didn't initially request a Mycoplasma PCR because, well, the lungs didn't look like Mycoplasma lungs.
It's weird how distinctive these different bacterial infections can be. And after you see dozens of gnarly cow lungs, you get a feel for how the different bacterial pneumonias present grossly. My pathologist agreed--the tissue damage we saw on the microscope slides of the lungs was most consistent with Mannhemia. How come we didn't culture it? Sometimes that happens. Failure to culture doesn't mean it wasn't there.
But my vet friend kept going on about this "bovoculi"--and I finally put it together.
Mycoplasma bovoculi--get it? bov = cow, oculi = eye--is a Mycoplasma implicated (link will open a PDF) in the past few years in a particularly nasty cow conjunctivitis. I found out that it likes to hang out with its friend Mycoplasma bovis. Which we found in the lungs of these cows when I had the PCR test run.
Some vet school adages really prove to be true, over and over. Common diseases commonly present uncommonly. I missed the Mycoplasma connection in this case, but I guarantee it won't happen again.
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