Influence of euthanasia, the intensity of inflammatory lesion and viral load in the laboratory diagnosis of rabies in cattle

ABSTRACT: This research reports the use of different diagnostic tests in cattle, naturally infected by Rabies lyssavirus (RABV), and correlates positivity with clinical moment euthanasia, intensity inflammatory lesion viral load. It also highlights possibility euthanasia early stages disease as a way to improve animal welfare. For that, samples 34 bovine brains were collected for analysis, preserved 10% buffered formaline refrigerated subsequent freezing. The subjected direct immunofluorescence antibody technique (DFAT) tests, isolation cell culture (VICC), histopathology hematoxylin eosin staining (HE), immunohistochemistry (IHC), Shorr stainied neural tissue smears (DSS), Reverse transcription polymerase chain reaction (RT-PCR) quantitative reverse transcriptase (qRT-PCR). areas used analysis cerebellum, parietal telencephalon thalamus. Samples Negri bodies (NBs) or immunostaining at least one analyzed considered positive. study histological lesions, lesions classified into grades 0, 1, 2 3 test presence absence NBs three analyzed. To verify influence evolution, 4-four groups created according animal’s status being: M1 = euthanized while standing, M2 when sternal recumbence, M3 lateral M4 natural death. Of evaluated, IHC was positive 100% cases, DFAT 97.05% them, this negative sample RABV confirmed VICC. ere seen 88.23% DSS 82.35% them. All techniques showed cases all Each case two methods. that contained rabies other tests. In study, it observed variables (intensity injury evolution euthanasia) had an only on HE techniques, which are based NB form diagnosis, but did not interfere effectiveness diagnosis performed detecting antigen IHC. isolated included present have genetic lineage characteristic hematophagous bats Desmodus rotundus. evaluation qRT-PCR amount virus work shows safe techniques. They capable even animals mild intensities lesions.