Objective—To develop an aerosol exposure method
for induction of brucellosis in rhesus macaques
( Macaca mulatta ).
Animals—10 adult rhesus macaques.
Procedure—8 rhesus macaques were challenge
exposed with 102 to 105 colony-forming units of
Brucella melitensis 16M by use of an aerosol-exposure
technique, and 2 served as control animals. All
macaques were euthanatized 63 days after challenge
exposure. Gross and microscopic lesions, bacterial
burden in target organs, and histologic changes in tissues
Results—Grossly, spleen weights were increased in
exposed macaques, compared with spleen weights in
control macaques. Histologically, there was inflammation
in the liver, kidneys, spleen, testes, and epididymides
in exposed macaques. The spleen and
lymph nodes had increased numbers of lymphohistiocytic
cells. Morphometrically, the spleen also had an
increased ratio of white pulp to red pulp. Areas of
hepatitis and amount of splenic white pulp increased
with increasing exposure dose.
Conclusions and Clinical Relevance—Pathologic
findings in rhesus macaques after aerosol exposure
to B melitensis are similar to those observed in
humans with brucellosis.
Impact for Human Medicine—These results may aid
in the development of a vaccine against brucellosis that
can be used in humans. ( Am J Vet Res 2004;65: