Eperythrozoon or Mycoplasma haemolamae:
New Name for an Old Problem
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
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