Amebíase sistêmica e toxoplasmose associadas à cinomose em cães no Semiárido da Paraíba.

Abstract

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.