10-20-04

 

Derek Foster, DVM

Colorado State University
Department of Clinical Sciences

 

Eperythrozoon or Mycoplasma haemolamae:  New Name for an Old Problem

 

One beautiful Colorado evening, you arrive home to find Bonnie, one of your favorite alpacas, weak, down, and breathing rapidly.  A quick exam by your veterinarian reveals that she is also pale and has a high heart rate, which also describes you at this point.  Some brief blood tests show that Bonnie is anemic – too few red blood cells – which helps explain her current signs of illness.  Upon microscopic examination of Bonnies’ blood, your veterinarian announces, “Bonnie has Mycoplasma haemolamae.”

 

To which, you (and most of the camelid industry and veterinary profession) respond, “Huh?  What’s that?”

 

Recently, the red blood cell parasite Eperythrozoon (commonly know as “Epe”) was renamed Mycoplasma haemolamae based on the results of genetic studies done on the organism.  This change in name is just that, a name change; it does not reflect any change in our understanding of the biology of this organism and the disease it causes.  If you have had to deal with Epe in your alpacas, you know that we in the veterinary profession still have a great deal to learn about this organism, but this article will summarize what we currently do understand.

 

What is it? 

Mycoplasma haemolamae is a small bacterium that lives on the red blood cells of camelids, and was first reported during the early nineties in Colorado and Illinois in a few sick or immunosuppressed llamas and alpacas.  Since its discovery, Mycoplasma haemolamae has been found throughout the United States.  Similar organisms are seen in pigs, cattle, dogs, cats, and many other species.

 

How common is it?

Mycoplasma haemolamae is found throughout the country and in the majority of camelids in Colorado.  Studies have shown that 25% of camelids nationwide have been infected, but up to 80% of camelids in and around Colorado are positive.

 

What does it do?

In the majority of infected alpacas, Mycoplasma haemolamae causes no disease at all.  Chances are that you may have an infected animal and do not know it.  The immune system of some camelids will effectively fight off the infection and rid the bloodstream of the organism.  Other animals’ immune systems will not completely eliminate the organism, but will keep it at such a low level that it does not cause disease.  These “carrier” animals are the most likely source of infection for other camelids.

 

In a few animals, the immune system is unable to effectively fight the infection, and the organism destroys red blood cells, causing anemia.  When the immune system fails to fight the parasite, the animal will begin to show signs of the disease.  These signs can appear as either acute or chronic disease.  The signs of acute disease include sudden weakness and inability to rise, while chronic problems may appear as lethargy, weight loss, or decreased fertility.  In animals that show any of these signs of disease, there is often an underlying problem that prevents the immune system from effectively fighting off Mycoplasma haemolamae.   These underlying problems may include pneumonia, ulcers, or even moving the animal to a new location.  Immunosuppression could be caused by a recent or chronic infectious disease.  Non-specific stress such as altered environment, changes in social status, changes in feed or water source, increased breeding use for males, or recent transportation can also be underlying causes of immunosuppression.  Unfortunately, it is often difficult to identify the fundamental cause of immunosuppression as the initiating event may already have resolved. 

 

How is it spread?

Although other species of animals can carry similar organisms, Mycoplasma haemolamae appears to only infect alpacas and other camelids.  Transmission of the organism from one animal to another is not completely understood, but believed to be spread only through contact with an infected animal’s blood.

 

Infected “carriers” most commonly do not show clinical signs, but may transmit the parasite through biting insects such as lice, mites, flies, or mosquitoes, reused needles, or blood transfusions.

 

How do we treat it?

In animals with anemia from Mycoplasma haemolamae, treatment with oxytetracycline can control the infection and allow the red blood cell count to return to normal.  Unfortunately, oxytetracycline is ineffective in completely eliminating the organism from these animals, so they may become carriers or may have a relapse if another stressful event occurs.  Currently, no medications have proven effective at eliminating the organism from “carrier” animals. 

 

Can we prevent it?

Because of the widespread nature of infection, complete prevention is difficult.  To decrease the spread, you should properly control insects including lice, mites, and biting flies.  A new needle should be used for each animal when treating or vaccinating your herd.  Preventing other diseases through proper vaccination, nutrition, and parasite control may help prevent severe disease from Mycoplasma haemolamae.  Prevention is best accomplished through routine veterinary care and proper husbandry. 

 

So in Bonnies’ case, a round of oxytetracycline effectively returned her to good health.  As she had just returned from a show, it was assumed that transporting her was the underlying stressor that initiated the acute disease.  Although she could have a relapse, Bonnie should go on to have a normal, healthy life.

 

 

----------------------------

10-12-04

 

The new name for eperythrozoonosis (commonly called "Epi") is mycoplasma haemolamae. 

Marcia Stille
Livestock Medicine and Surgery
CSU Veterinary Teaching Hospital
Fort Collins, Colorado  80523

 

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10-1-04


EPERYTHROZOONOSIS IN LLAMAS AND ALPACAS
Sharon Heisler, Veterinary Student
David E Anderson, DVM, MS, DACVS
Ohio State University


         Eperythrozoonosis is an organism that infects the red blood cells.
Their presence may trick the body's immune system into thinking that these
cells are foreign thus causing the immune system to destroy the cells. The
destruction of red blood cells may lead to life-threatening anemia.

         This organism has recently been renamed Mycoplasma haemolama. The
transmission of the organism is via biting insects.  Infection with
eperythrozoonosis is found worldwide, throughout the year, and in many
species, including swine, sheep, cattle, mule deer, elk, and
goats.  Clinical signs observed are often inappetance, wasting, and
occasionally fever.   Upon further examination one may notice pale gums,
indicating anemia, or even a yellow hue to the skin representing
jaundice.  Asymptotic carriers, those that are infected but showing no sign
of disease, are often a factor in maintenance of the organism within a
herd.  They go without treatment and therefore are infectious when bitten
by an insect and that insect continues to feed off other animals in the
herd infecting them in the process.
Eperythrozoonosis does not have to be the primary disease; in fact it is
often secondary to other clinical manifestation.  The most common
association is JLIDS (Juvenile Llama Immunodeficiency Syndrome), severe
intestinal parasite burden, and overwhelming stress.  These cases have a
more severe clinical presentation and may suffer repeated infections.
Examination of the blood under a microscope may or may not find the
organism on the red blood cell. If present, this observation makes a
diagnosis of eperythrozoonosis.  Blood work is indicated to evaluate the
animal to determine if anemia is present and if a blood transfusion is
warranted.  There are serologic tests available for eperythrozoonosis, but
interpretation is difficult. Recently, Dr. Susan Tournquist at Oregon State
University developed a PCR (polymerase chain reaction) test for Mycoplasma
haemolama. This test should be more accurate and improve our ability to
diagnose this infection and perhaps identify carriers of the disease.

         When anemia and clinical disease are associated with M. haemolama
infection, treatment
consists of tetracycline (20-mg/kg-body weight given daily by injection for
5 days). Be aware that reinfection is possible, especially with asymptotic
carries in the herd.  Treatment of the whole herd with tetracycline all at
once may help prevent a reinfection.  However, whole herd treatment success
is difficult to quantitate. The new PCR test may be our best tool to
accomplish this goal. A more logical approach may be to conduct herd tests
and treat only those animals suspected of being carriers - PCR positives.
Controlling the biting insects will also play a key role in preventing
eperythrozoonosis.

David E Anderson, DVM, MS
Diplomate, American College of Veterinary Surgeons
College of Veterinary Medicine
The Ohio State University
VISIT OUR WEB-SITES:                 http://www.vet.ohio-state.edu/docs/ClinSci/camelid/index.html        http://www.internationalcamelidinstitute.org

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