CASE SERIES OF AMYLOIDOSIS IN SERUM-PRODUCING HORSES OF
Fazenda SÃO Joaquim - Instituto Butantan.
Juarez Pinto Fernandes Távora1; Patrícia Stocco Betiol2; Ronaldo Azevedo Ferreira1;
Eliana Reiko Matushima2; Andréa Cristina Parra2; Marina Godoy Gimeno2; Luis Claudio
Lopes Correia da Silva2; Hisako Gondo Higashi1; José Roberto Marcelino1; Rosalvo
Guidolin1
Introduction: Reactive amyloidosis is considered the major cause of death in animals
used for commercial antiserum production as a consequence of prolonged antigenic
stimulation. In many cases, these animals develop amyloid deposition resulting in a result
of friable texture and even rupture of the hepatic capsule. These changes are
accompanied by tissue accumulation of insoluble fibrillar proteins in cavitary organs like
kidneys, heart, liver, spleen and adrenal glands, leading to dysfunction and insufficiency
of several organic systems. Case series: Five serum-producing horses from Fazenda São
Joaquim of Instituto Butantan died. From these, one belonged to a anti-diphteric serum
group, two to an anti-tetanus serum group, one to an anti-rabies serum group and one to
an anti-scorpionic-venom serum group. Two animals showed clinical signs of colic and
the other three suffered a peracute death. On necropsy, blood in the abdominal cavity,
enlargement of liver and spleen, a friable aspect of the liver and pale mucosal membranes
were observed. Microscopically, hematoxilin-eosin stain indicated areas of hepatocyte
atrophy with deposition of an amorphous-eosinophilic substance, the same material also
found in several areas of the spleen. For the confirmation, sections were also stained with
Congo red stain, which is more specific for amyloid material. Amyloidosis was worse in
the three animals used for more than eight years for serum production (anti-diphteric,
anti-scorpionic-venom and anti-tetanus serum groups). Discussion: This paper confirms
many other earlier reports, which showed that continuous hyper-immunization for
prolonged periods in horses is associated with hepatic and splenic changes due to
amyloid deposition. Conclusion: This is the first scientific report of amyloidosis,
confirmed by clinical and microscopic examinations, in serum-producing horses in Brazil.
1
2
Instituto Butantan, São Paulo, Brasil.
Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo, São Paulo, Brasil.
Avenida Dr. Orlando Marques de Paiva, 87, cep 05508-000, São Paulo, Brasil. [email protected]