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Mycoplasma

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12/30/01

Mycoplasmas are slow-growing micro-organisms, members of the mollicute family, and are characterized as virus-like infectious agents, somewhere between a virus and bacteria. They lack the normal rigid peptidoglycan cell wall of bacteria, which allows them to invade all the tissues and organs of the body, including the brain, causing complex symptoms. There are hundreds of different mycoplasma subtypes and strains.

The two most common isolation sites in humans are respiratory and genito-urinary tracts, although isolation from synovial fluid and other anatomical sites have been reported. Mycoplasma are currently under intense study as being at least a cofactor in the causation of AIDS, Fibromyalgia Syndrome (FMS), Gulf War Illness (GWI), Rheumatoid Arthritis (RA), and Chronic Fatigue Syndrome (CFS).

Mycoplasmas are known to cause serious and often fatal illness in goats. These are caused by several different subtypes and strains. These include M. capricolum subsp capripneumoniae, M. capricolum subsp capricolum, M. conjunctivae, M. mycoides subsp. capri, M. mycoides subsp. mycoides LC, M. putrefaciens, M. yeatsii, A. oculi. For those who like to surf for pictures, the following links to some of the more common types are provided:

A test for detecting Mycoplasma in the blood, known as the polymerase chain reaction (PCR) has been developed, but it may not be available through all labs at this time. Although they have probably been around for a long time, mycoplasma infections appear to be on the increase in goat herds and will certainly be receiving increased scrutiny in the future.

In goats, the disease tends to lead to five basic problems:

Respiratory (Contagious Caprine Pleuropneumonia)
M. agalactia, M. mycoides mycoides LC, M. strain F38, M. mycoides capri
This disease appears to be increasing in frequency among adult and baby goats around the world. It is extremely contagious and results in a very high percentage of deaths in a herd. First signs are cough, shortness of breath, runny nose, loss of appetite and severe weakness. It can be accompanied by a high fever, with the head lowered and/or extended and an arched back. Since the causative agents can also be found in cases of mastitis and abortion, it is indeed possible that the disease can be transmitted from an infected dam; although it is generally presumed to be spread via aerosol droplets. Likewise, another of the symptoms that can accompany CCP is arthritis, but this will be discussed below. There are some forms of the disease which show no respiratory signs, but merely weakness and a high fever (septicemia, see below).

Arthritis (polyarthritis)
M. agalactiae, M. capricolum, M. mycoides
This is the situation most likely to be seen by goat herders. Healthy young kids will suddenly start limping, hunch their backs, stop eating, go down crying in obvious pain and die within a few hours. Blindness has also been reported. In some instances, the mothers will be obvious cases of mycoplasma mastitis (see below), but the link is not always guaranteed. The diagnosis must be differentiated from enterotoxemias of Clostridium perfringens C and D and "navel ill."
Mastitis ("Contagious Caprine Agalactia")
M. agalactiae, M. capricolum, M. mycoides, M. putrefaciens
This topic has been covered at our page on mastitis. The dam will show the signs of mastitis discussed there (with the odor of putrification if caused by M. putrifaciens), but the kids may show any or all of the mycoplasmal symptoms of pneumonia, arthritis, conjunctivitis (with yellow discharge), septicemia, fever, weakness, etc. leading to a very high mortality rate.
Conjunctivitis (Infection of the lining of the eye)
M. agalactiae, M. conjunctivae, M. mycoides
It will be practically impossible to tell this type of conjunctivitis from the many other common types, unless it occurs with some of the mycoplasmal symptoms mentioned above. We have had some people report a yellow discharge in cases where this disease has been suspected, but this does not have scientific support.
Septicemia

M. capricolum, M. mycoides, M strain F38
This is a really serious perdicament wherein the infection has more or less penetrated throughout the entire body. It frequently results in rapid death and will resemble the situation discribed under arthritis above. It can probalby be the end result of any of the above.
Treatment

There are some sources which recommend the strict culling of all cases of mycoplasma infection due to the fact that successful treatment may result in the creation of carriers which can later infect new additions to the herd or someone else's animals if the carriers are sold. This may be a matter of personal choice and we do not have enough information to judge the validity of these claims.

If there is going to be any success at all, treatment must be immediate and vigorous. All showing any of the above signs should be isolated at once. All members of the herd should be started on a course of antibiotics. Most authorities recommend the use of tylosin (Tylan200®) IM for 3 or 4 days. Others have had success with high doses of tetracyclines such as LA200®. (We would choose the Tylan®.) There is some evidence that penicillin may do more harm than good. We STRONGLY suggest that you follow the advice of your veterinarian.

Supportive therapy is also important. If the mother has any signs of mastitis (or any of the other mycoplasmal symptoms), the kids should either be bottle fed off other dams or her milk should be pasteurized.

There is currently some speculation as to the transmission of mycoplasmas to humans. Although there is increased attention to possible human disease implications, there has not been enough solid evidence that we know of to justify the classification of mycoplasma as a true zoontic disease. None of the subtypes discussed above have been mentioned as being present in human patients that we know of. But more research in this area is certainly in order and will probably be undertaken in the future. Milk taken from an infected doe would best be disposed of and normal precautionary measures such as milking known sick animals last should always be followed.

Comments

In preparing for this page, I have been deeply fascinated by this topic. It is one which shall certainly hold a lot of interest for veterinary (and human medical) researchers in the near future. There are obviously an awful lot of blank pages to fill in. In our "Symptoms pages" (goatwisdom/alpha/a - z) you will notice the Heidi Disease listed quite frequently. This is a disease which went through some of the kids in our herd a few years back. I was never able to make a definite diagnosis, but in preparing for this page, I have an inkling that it may have been the result of one of the types of mycoplasma.

There seems to be a real shortage of "down and dirty" information about this topic. If anyone has first-hand experience with this disease or the symptoms outlined above, we would be most eager to hear from you.



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