From the State Vet’s Office

WHAT YOU NEED TO KNOW ABOUT ANAPLASMOSIS

DIAGNOSIS AND TREATMENTS

BY DR. TONY FRAZIER

Obviously, what you should know about anaplasmosis may vary depending on your proximity to the cattle business. I believe that if you are a cattle producer, you should have a basic understanding of the disease. If you are pretty much on the other end of the spectrum and only eat beef, you should know that anaplasmosis is not a food safety issue. It can infect some wild ruminants, but generally does not cause disease.

If you do not have cows but have friends who own cattle, I suggest you go ahead and read the article. That way, when your cattle-producing friends make some statement as, “I have had a few abortions in my cow herd and the normal causes have all come up negative.”

Then you can interject, “Have you tested for anaplasmosis?”

When they raise their eyebrows and ask how you know that, you just smile and say, “Well, I read Dr. Frazier’s articles. Don’t you?”

Anaplasmosis marginale is a special kind of bacteria known as a rickettsia. Rickettsia causes human diseases like Rocky Mountain spotted fever and Lyme disease. The organism manages to get into the red blood cell, causing significant damage. The number of red blood cells doubles about every 48 hours. As the cells become damaged, the body takes them out of circulation. Eventually, after two to six weeks of this, the body is not able to keep replacing the red cells that are destroyed and the cow becomes anemic. At this point the anemia may become so severe the cow may die within a few days.

Anaplasmosis has been relatively common in many of the Gulf Coastal states for a long time. In the past few years, the disease has become more common in areas of Central and North Alabama. I have friends who have practiced in parts of Texas, Louisiana, and Mississippi who tell me that their clients are familiar enough with the disease that they call and say, “Hey Doc, I need you to come out to my place. I’ve got another one of those anaplaz cows.”

Now I will say that a client diagnosing anaplasmosis is not very scientific. But, if the disease is advanced enough, it is likely that someone who has seen this disease would recognize it if it shows up again. In the advanced stages of the disease, cows usually tend to be somewhat aggressive. The textbooks describe these cows as “hyperexcitable.” I like to describe them as trying to get into your back pocket. Along with that, depending on the duration of the disease, their mucous membranes may be a bit yellow or icteric. If you put the behavior and the yellow mucous membranes together in the late summer or fall of the year, chances are good that you may have anaplasmosis. Now I don’t want you diagnosing something like that yourself. If you’ve got a cow that’s sick, you need to put down whatever you are doing and call the veterinarian.

The reason for late summer through fall incidence of the disease is that the main source of transmission from animal to animal is insects, mainly horse flies. But the disease can also be spread by certain ticks. The organism can also be spread by using the same needle to vaccinate or treat, dehorning equipment, tattoo pliers, or castrating equipment. The occasional winter outbreak is likely caused by contaminated needles.

One of the aggravating problems with anaplasmosis is the development of carrier animals. Not every cow that gets sick with this disease will develop clinical symptoms like those we just discussed. Some may become infected and just become poor doers. They lose weight and their reproductive system may pretty much shut down. Others may be able to become pregnant but lose the calf in the later stages of pregnancy (refer to paragraphs 2-4). Also, bulls may experience infertility. It can be difficult to get it out of a herd once it is introduced.

Back when I was in practice, anaplasmosis did not seem to be terribly prevalent, especially in North Alabama where I began practicing. So, it wasn’t high on the list of causes for cows to abort. We are now seeing an increasing trend of cows that seem reasonably healthy and abort and test positive for anaplasmosis. We did have several cases detected at our diagnostic labs last year.

A real train wreck that we sometimes hear about occurs when cattle that have never been exposed to the organism are introduced into a herd that has carriers. In such cases, up to 50% of the susceptible cattle may become infected and die. And those that do not die may have an extremely long convalescent period.

If there is any positive aspect of anaplasmosis I guess that it would be that it is treatable, even when the cow seems to have one or two feet in the grave. If she has three feet in the grave, she probably won’t make it. But you can treat a really sick cow with injectable tetracycline, and they will often respond. Also, another commonly used method of controlling anaplasmosis is by adding a feed-grade chlortetracycline to the feed or mineral supplements. As you are probably aware, feeding this product will now require a veterinarian to sign a Veterinary Feed Directive (VFD) with appropriate dosages. As I mentioned earlier, anemia, from the destruction of infected red blood cells, is what causes all the clinical signs in cattle. Sometimes the blood can be so thin that it looks more like cherry Kool-Aid than blood. Anyway, some cattle may need a blood transfusion along with the tetracycline if their red cell count gets too low.

There is also a vaccine available that can be used in herds that are known to be infected with anaplasmosis. Several years ago, there was a commercial pharmaceutical company that produced the vaccine. Now the only vaccine available is from a laboratory at Louisiana State University. And while anaplasmosis is not a regulated disease, I have to approve all animal vaccines used in Alabama, so I have approved that vaccine to be used through licensed veterinarians.

So, you now have a working knowledge of anaplasmosis. Many of you reading this article have already had run-ins with the disease. For other cattle producers, it is something you should be familiar with. And if you are ever on the game show "Jeopardy" and the opportunity arises, you won’t hesitate to jump in there and say, “Alex, give me anaplasmosis for $600.”