Banca de DEFESA: ERIKA RAMOS MELLO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : ERIKA RAMOS MELLO
DATE: 27/07/2023
TIME: 10:00
LOCAL: Instituto de Veterinária
TITLE:

Clinical-pathological evaluation in swine diagnosed with Senecavirus A in Southeast Brazil

KEY WORDS:

swine, pathology, virus

PAGES: 70
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Patologia Animal
SUMMARY:

Senecavirus A (SVA) is a virus from the Picornaviridae family, the same as the foot-and-mouth disease virus (VANNUCCI et al., 2015). Both have similar clinical evolution and are distinguishable only with laboratory diagnosis (HAUSE et al., 2016) and suspected cases must be immediately reported to the Official Veterinary Service (SVO) (BRASIL, 2013). The first reports of the disease in the world occurred in 2007 in Canada and in 2015 in Brazil, with outbreaks in several states (LEME et al., 2015). In the few published works, the clinical-pathological aspects of Senecavirosis have been neglected by genetic approaches. Thus, the present study aims to describe the clinical, hematological and anatomopathological changes in pigs diagnosed with SVA in the state of São Paulo. The project was approved by CEUA/IV/UFRRJ (6856071221). This is a descriptive observational study with a convenience sample in which the sample n was equal to the series of SVO collections for the investigation of vesicular disease between October 2021 and April 2022. The clinical examination, blood collection and organ fragments were carried out on the farms and in the slaughterhouse. Virological tests were carried out by the Federal Laboratory of Agricultural Defense in Pedro Leopoldo/MG. The assay for detection of SVA by molecular techniques of the RT-qPCR type was carried out according to the Reference Laboratory Assay Method MET/LREF/030 - V.1 of the Pan-American Foot-and-Mouth Disease Center. Blood counts were performed according to Thrall et al. (2015). For biochemical analyses, commercial LabTest® kits were used according to the manufacturer's recommendations and addressed the hepatic profiles of alkaline phosphatase (AP), gammaglutamyltransferase (GGT), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and total bilirubin (BT) ; renal (urea and creatinine) and muscle creatine kinase (CK) and lactate dehydrogenase (LDH), both performed by the Laboratory of Clinical Pathology at UFRRJ. The clinical examination was performed according to Feitosa et al. (2014). During slaughter, fragments of the stomach, small and large intestines, spleen, kidney, bladder, tongue, heart, lung, tonsils, liver and central nervous system were collected, fixed in 10% buffered formalin and routinely processed at the Histopathology Laboratory of the Department of Pathological Anatomy at UFRRJ. Among the vesicular diseases of swine, Foot and Mouth Disease and Senecavirosis are clinically indistinguishable (HAUSE et al., 2016), therefore the FMDV-ELISA 3ABC Prionics test for Foot and Mouth Disease was performed, with a negative result. Three Senecavirose outbreaks were confirmed in the state of São Paulo, in the municipalities of Cerqueira César, Águas de Santa Bárbara and Iaras, with samples of 8, 12 and 16 animals, slaughtered at 140, 159 and 151 days of age, respectively. Morbidity was 30% in the three foci and mortality was 1.74% in the first two and 1.96% in the third. Clinically, in addition to dermatitis and hyperkeratosis in the distal region of the limbs, non-hemorrhagic enteritis, non-productive cough and tail eating, vesicles on the limbs and snout, lameness, difficulty walking, anorexia and lethargy, symptoms already described in this infection ( OLIVEIRA et al., 2017; ABCS, 2019). There are no studies that correlate SVA infection with blood count or serum biochemistry changes. No noteworthy alterations were observed in the blood count, however, the biochemical examination revealed an increase in the mean values of AST, LDH and CK, a probable consequence of muscle injury. CK values, whose reference ranges from 2.4 to 22.5U/L, were increased in all animals, ranging from 1900U/L to above the detection limit of the method used, possibly associated with SVA infection. Macroscopic evaluation of the heart revealed pale areas with multifocal distribution, changes not reported on post mortem inspection in pigs with SVA (LISE et al., 2019). Microscopic examination showed, in the heart and in the skeletal striated muscle, several groups of eosinophilic myofibers with pyknotic nuclei, sometimes with mononuclear inflammation and areas of fibrosis. Additionally, there was mild to moderate lymphoplasmacytic atrophic enteritis in the small intestine, moderate necrotizing glossitis, mild to moderate splenic lymphoid hyperplasia, mild to moderate lymphoplasmacytic interstitial nephritis, vacuolation of renal tubular epithelial cells, ballooning degeneration of bladder transitional epithelium cells, vacuolization of the tongue epithelium, intracytoplasmic eosinophilic structures suggestive of inclusion bodies in the tongue epithelium, vacuolation of hepatocytes, mild periportal lymphoplasmacytic hepatitis, bronchointerstitial pneumonia. The results of histopathology differ from those of the State University of Iowa, in which specific microscopic lesions other than ulcerative lesions due to vesicle evolution were not observed (GUO et al., 2016). On the other hand, part of the results has already been described by Oliveira et al. (2017) and Leme et al. (2016) and intracytoplasmic inclusion bodies in the tongue epithelium had not yet been described. SVA infection causes relevant alterations in serum biochemistry, possibly caused by muscle injuries and macroscopic and microscopic evaluations reveal injuries that can help in the diagnosis; some of which have never been previously described in the literature.

COMMITTEE MEMBERS:
Presidente - 2606155 - VIVIAN DE ASSUNCAO NOGUEIRA CARVALHO
Interna - 2572430 - CRISTIANE DIVAN BALDANI
Externa ao Programa - 3324429 - ANDRESA GUIMARAES - UFRRJExterno à Instituição - FABRICIO NASCIMENTO GAUDENCIO - CESVA
Externa à Instituição - MARIANA CORREIA OLIVEIRA - UES
Externa à Instituição - SAMAY ZILLMANN ROCHA COSTA