Case
Study: Avian TB WHITE-CAPPED PIONUS PAIR
Submitted by Burloak Animal Clinic, Oakville, Ontario
On February 1, 2002 a client arrived at our
clinic with a recently deceased female White-capped Pionus.
The client was surprised since the hen had appeared in perfect
health the evening prior. Visually, the hen appeared to be
in good condition with no obvious signs of disease. Therefore,
after a brief inspection the bird was prepared for a necropsy
and subsequent histopathological examination to determine
the exact cause of death.
The necropsy revealed large white nodules attached to the
birds lungs, characteristic of tuberculosis infection. Following
this inspection, a small tissue sample was isolated from the
bird and set aside for PCR (DNA) testing, while the rest of
the body was prepared, and sent to the University of Guelph
for histopathological examination.
The examination results arrived a few days later and revealed
the presence of "Nodular Granuloma compatible
with Mycobacterium avium", which was in accordance
with earlier observations of white nodules in the lungs. However,
in order to confirm these results, a small tissue sample was
sent for DNA testing to HealthGene laboratory. Surprisingly,
HealthGene’s PCR-based test revealed that the tissue was negative
for the presence of Mycobacterium avium. Clearly,
these results were not in agreement with the examination results
obtained from the University of Guelph. After notifying the
University of this discrepancy, they proceed to forward the
samples to Canada’s National Microbiology Laboratory located
in Winnipeg. Interestingly, the Winnipeg laboratory also failed
to detect the presence of M. avium, thus supporting
HealthGene’s results. HealthGene laboratory continued DNA
testing and determined that the cause of the white nodules
could be attributed to Mycobacterium genavense infection.
The Winnipeg laboratory proceeded to conduct a microbiological
test for M. genavense and confirmed these findings.
After receiving these results, the male White-capped Pionus
originally housed with the infected hen was tested by HealthGene
for M. avium and M. genavense. As suspected,
the male tested positive for Mycobacterium genavense and was
subsequently treated over a nine-month period. A follow-up
DNA test was recently conducted and indicated that the bird
was free of M. genavense infection. As a precautionary measure,
the owner of these birds proceeded to check the rest of the
aviary by DNA testing for M. avium and M. genavense
infection. Luckily, all the results were negative, indicating
the infection had not spread.
