Tortuga Gazette 39(6): 4-5, June 2003
MYCOPLASMA LADY
Professor Mary Brown
Interviewed by Stephanie Pappas
PART 2
Facts on upper respiratory tract disease in tortoises and turtles are revealed in this exclusive interview with the world renowned scientist, Professor Mary B. Brown, Ph.D. She was part of a team that worked to identify Mycoplasma as the organism causing URTD in 1992. Professor Brown has continued to address new and difficult questions about the effects of this disease on tortoises and she contributes highly valued expertise to many organizations working to save tortoises. The interview took place in Palmdale on January 25, 2003 when Dr. Brown was visiting California and about to be honored by the Desert Tortoise Preserve Committee with the Golden Tortoise Award.
Stephanie Pappas
Dr. Brown, California Turtle and Tortoise Club 's (CTTC) Adoption Committees receive many tortoises every year that are
sick with runny noses. What is the best way adoption chairs can hold turtles and tortoises with URTD symptoms?
Mary Brown
The most important point is that you quarantine the tortoise with the runny nose from others and that you spray down the
area with bleach after the animal has been there. If you use plastic containers it is easy to wash out with bleach, but
if the area is dirt then you have to worry that some bacteria is left behind. If you use a grass area that is designated
for an ill animal, you should keep it as far away as possible from your healthy tortoises. We did one small pilot study
where we took Gopher tortoises with active runny noses out of a pen and immediately put healthy tortoises in and we did
not get any transmission of the disease in the burrows, but this was a very limited study. I suspect that long-term
survival of M. agassizii is not occurring and that if you left an area for a week you should be very safe. If you
spread the area with bleach, you would be even safer.
Stephanie Pappas
In order to prevent URTD from spreading to healthy captive and native populations of tortoises, some rescue
organizations have discussed euthanizing all tortoises with severe runny nose syndrome. What is your feeling on this
topic?
Mary Brown
That is a very tough question and really hard to answer! One of the biggest problems we face is differentiating between
conservation values, risk to the wild populations, and the genuine love that people have for these animals. It is
difficult to euthanize an animal. In captivity there are tortoises that live for a very long time and are carriers of
M. agassizii for life. These tortoises may be clinically ill and have symptoms on and off. Remember, this is an
intermittent disease and the tortoise is not always going to be sick. They recover from clinical signs with antibiotic
therapy and get over the clinical signs. The damage is to the respiratory tract, but if the tortoise is properly fed and
cared for they can live for a very long time. The animal will never be cured, but they will be in a holding pattern for
life. The clinical signs may reappear on and off throughout the life of the tortoise, and you will need to treat the
animal when symptoms appear. If you are going to keep the tortoise, be responsible and do not infect other tortoises and
turtles. Never release the tortoise back into the wild populations and when it is ill with clinical symptoms, segregate
it from the rest of your population.
Stephanie Pappas
Dr. Brown, what is the best treatment for URTD today and what is the difference in treating with oral medication versus
injections?
Mary Brown
Baytril is one of the best choices! However-Baytril is Baytril, it does not matter if it is taken orally or given by
injection. We published data on antibiotic resistance and sensitivities. Mycoplasma are sensitive to Baytril,
Tetracycline, and Doxycycline, but Baytril seems to be easier on the animal's gastrointestinal tract. The treatment is
completely dependent on how the organism responds to the antibiotic, but is also dependent on how the tortoise responds
to the infection, how severe the disease is, and how long the clinical signs have been there. Mycoplasmosis is one of
those diseases where the host (the tortoise) participates! If you have a tortoise that is responding vigorously to the
treatment, that means you may have very severe lesions on the respiratory surface. On the opposite side, a tortoise that
is not responding very well to the treatment is an indication that the tortoise has an immune response to the bacteria
causing the disease.
Stephanie Pappas
What do you do when you have treated a tortoise for 20 plus days, 3 or 4 times in a row and the runny nose continues to
be persistent?
Mary Brown
Well if the animal is eating well, active and not lethargic, that is an indication that it should do well for this bout
of infection. What you need to worry about is a tortoise that is very lethargic and not eating at all. This is a sign
that the disease is very severe. Most of the tortoises with URTD do very well in captivity because of proper husbandry
and care, but we have seen cases that are just like an avalanche and there is no hope for the animal. Remember, I am a
research specialist not a reptile medicine veterinarian.
Stephanie Pappas
Okay, then let 's re-focus on some unanswered questions about transmission. Earlier we discussed horizontal
transmission, but we did not discuss vertical transmission-from parent to egg.
Mary Brown
The studies on vertical transmission, from parent to egg, in tortoises, are very inconclusive and insufficient at this
time, and this is why. We know that in poultry Mycoplasma gallisepticum can be transmitted in the egg, but occurs
only 10%of the time and only at very specific points of egg production. Keep in mind that chickens lay eggs every day,
but tortoises only lay eggs once or twice a year. Val Lance and David Rostal did some studies with sick female tortoises
showing clinical signs of disease. Half of the females in the study would not nest and lay eggs when they were ill. So,
if the best transmission case is 10%in poultry laying eggs every day, you figure that transmission would be equal or
less than that in tortoises. To actually see if egg transmission in tortoises occurs we would have to statistically
study 100 clutches and analyze various stages of clinical illness at various stages of egg shell production. If a female
tortoise has heavy mucous which is when you have the highest amounts of Mycoplasma levels present, this would be
when you would have the greatest risk of Mycoplasma in the blood stream and the greatest chance of it going to
the egg. If that occurred after the shell was formed and no longer porous, maybe the Mycoplasma would not
penetrate the shell. But if it happened before the egg shell was completely formed, then you might have transmission.
The point is that egg transmission occurs at very low rates and I don 't believe anyone is going to give up a hundred
clutches of eggs to do a study. Besides there are better studies and other questions we can answer with the use of fewer
animals. More important is what we do know about the transmission of URTD. If an infected tortoise lays eggs in a pen
and hatchlings come out and are in contact with an adult with URTD, then the hatchlings get very sick. So you want to be
sure that you do not leave a sick adult tortoise in with the eggs, and don 't let hatchlings come in contact with sick
adults.
Stephanie Pappas
Dr. Brown, if you have a tortoise that has an active runny nose does that mean that the tortoise is M. agassizii
positive and if you have a tortoise that has no clinical signs of the disease does that mean that the tortoise is
Mycoplasma free?
Mary Brown
If a tortoise has a runny nose it does not necessarily mean the tortoise is positive for Mycoplasma, because a
runny nose could also be due to a cold, an allergy or can happen after drinking water. However, if the tortoise has
thick mucous coming out of its nose, I would be concerned that the tortoise is sick. It still may not be Mycoplasma,
but could be another agent causing the symptoms. A bigger concern than a tortoise with thick mucous is one that looks
healthy for a time and then later starts showing clinical signs of nasal discharge. Those are the really difficult ones!
We had some tortoises that were culture negative for a year, but had tested seropositive for M. agassizii. This
means that they had the organism but did not show any clinical symptoms. We did a study with these symptom-free
tortoises where we introduced the organism and they all got sick much faster. The first two weeks they were more
severely ill and had higher numbers of organisms present than an animal that had seen the disease for the first time. So
remember, you may have a tortoise that looks clinically healthy but in fact is a prime candidate harboring the organism,
and if re-exposed a second time to the organism, the animal will get very, very sick.
Stephanie Pappas
Dr. Brown, are there any statistics on the tortoises that have shown clinical signs and tested positive versus tested
negative for M. agassizii?
Mary Brown
We have tested over six or seven thousand Gopher and Desert tortoises. Most of the samples are from veterinarians, and
private collectors, as well as various studies. We have observed a very high correlation between clinical signs, runny
noses, and ocular discharge. Clinically ill tortoises that have histology or microscopic evidence of damage are almost
always uniformly positive for M. agassizii. I would say it is greater than 90%.If you look at the tortoises that
have been tested for M. agassizii, the majority were seronegative. I would say approximately 25% or less actually
tested positive. I will also say that the highest percentage of positive animals come from captive tortoises -by far. We
also have data on tortoises that look clinically fine, perfectly healthy and test positive for M. agassizii.
Actually, the worst microscopic lesions we have seen were from tortoises that looked healthy and tested seropositive. So
just because it looks healthy it does not mean that it is!