FRADE, M. T. S.; http://lattes.cnpq.br/2327295678108013; FRADE, Maria Talita Soares.
Résumé:
Canine distemper is a disease often diagnosed in routine Small Animal Clinic and
Laboratory of Animal Pathology, Federal University of Campina Grande, Campus de
Patos, Paraíba. With immunosuppression resulting from infection with canine distemper
virus co-infections with opportunistic agents can be observed. The objective of this
study was to describe the opportunistic protozoan infections and its systemic
complications in dogs infected with the virus of distemper, three cases of infection with
Acanthamoeba sp. and five cases of Toxoplasma gondii. To this end, this dissertation
was formatted into two chapters, consisting of two original articles. The first submitted
to Veterinary Parasitology describes three cases of systemic infection Acanthamoeba sp.
in dogs with distemper, featuring the epidemiological, clinical and pathological aspects
of disease diagnosed in the semiarid region of Paraíba, Northeast Brazil. In this report,
the affected dogs developed progressive neurological and respiratory signs that
progressed to death within 2-20 days. At necropsy there was irregular and with yellowreddish
nodules randomly distributed in the lungs, heart, kidneys, spleen, lymph nodes,
adrenals, and intestine. One dog had foci of malacia in the parietal cortex and another
one in the caudate nucleus. Histologically, pyogranulomas with areas of necrosis and
hemorrhage in all organs affected were observed, associated with myriads of
intralesional amoebic trophozoites. All three cases were concomitant canine distemper,
that possibly triggered immunosuppression in the dogs. The diagnosis was performed
through microscopic findings of infection by free-living amoebae and confirmed
Acanthamoeba sp. by immunohistochemistry. The second article, submitted to Brazilian
Veterinary Research, report the occurrence of five cases of toxoplasmosis associated
with distemper in dogs in the semiarid region of Paraiba, four with involvement of the
brain and one with involvement of the lung, describing the clinical, pathological and
immunohistochemistry characteristics. To this end, all were reviewed necropsies
records of dogs diagnosed with canine distemper in the Laboratory of Animal
Pathology, Federal University of Campina Grande, Campus de Patos, Paraíba, in the
period from January 2003 to December 2012. IHC was performed on cases that had a
cystic characteristics intralesional of protozoan, Toxoplasma gondii compatible with
anti-Toxoplasma gondii. The clinical alterations observed in these cases were similar
and consisted of signs digestive, respiratory, neurological and ocular lesions suggestive
of infection with canine distemper virus. Histologically in the encephalon had
multifocal areas of malacia, and these areas were observed near basophilic round
structures, characteristic of cysts of Toxoplasma gondii. Encircling these areas had
mononuclear inflammatory infiltrate composed mainly of lymphocytes, plasma cells,
macrophages and rare neutrophils. In the lung had thickening of the alveolar septa by
mononuclear inflammatory infiltrate composed of macrophages, lymphocytes and
plasma cells, with moderate proliferation of type II pneumocytes. There were multifocal
to coalescing areas of necrosis with macrophages associated with T. gondii. The
histological findings compatible with distemper were characterized mainly by nonsuppurative
encephalitis, demyelination and perivascular cuffs discrete, associated the
inclusion bodies eosinophilic intranuclear and/or intracytoplasmic in astrocytes, neurons
and ependymal cells. There were also inclusion bodies in extraneural organs. The
diagnosis of toxoplasmosis associated with infection with canine distemper virus in the
five cases studied was based on the microscopic findings, and confirmed by
immunohistochemistry. Toxoplasmosis shall be included in the differential diagnosis of
dogs with severe progressive systemic signs, especially when respiratory and neurologic
involvement. Has been observed in cases of distemper with simultaneous occurrence of
other agents that evolution to animal death occurs more quickly and severely. Upon the
occurrence of systemic infections by infectious agents and especially when there is
involvement of the nervous system by opportunistic agents, a primary cause, such as
distemper, should be investigated.