Banca de QUALIFICAÇÃO: ALICE GONÇALVES DOS REIS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE: ALICE GONÇALVES DOS REIS
DATA: 29/07/2026
HORA: 09:00
LOCAL: DMV08
TÍTULO:

Epidemiology and Surveillance of Enzootic Bovine Leukosis and Bovine Brucellosis: Applications to Control and Eradication Programs

PALAVRAS-CHAVES:

epidemiological surveillance; animal health; associated factors

PÁGINAS: 50
GRANDE ÁREA: Ciências Agrárias
ÁREA: Medicina Veterinária
SUBÁREA: Medicina Veterinária Preventiva
RESUMO:

Infectious diseases remain one of the major challenges in the livestock production, causing significant impacts on productivity, animal welfare, and the profitability of production systems. In response, control and eradication programs have been implemented in several countries to reduce the occurrence of these diseases and mitigate their consequences. The planning, implementation, and continuous improvement of such programs trust on robust epidemiological evidence capable of characterizing disease occurrence, identifying populations at greater risk, and assessing the performance of diagnostic tools, thereby supporting evidence-based epidemiological surveillance. In this context, the present dissertation aimed to generate evidence to improve the epidemiological surveillance of two major cattle diseases: enzootic bovine leukosis (EBL) and bovine brucellosis. The first chapter consisted of a cross-sectional study designed to estimate the prevalence of EBL in the state of Minas Gerais, Brazil, and to identify factors associated with infection. A total of 13,650 serum samples from 1,617 herds distributed across seven regions of the state were analyzed using a commercial blocking indirect ELISA. The true herd-level prevalence was estimated using a Bayesian latent class model that accounted for the sensitivity and specificity of the diagnostic test. Associated factors were identified through multilevel logistic regression. The estimated true herd-level prevalence ranged from 59% to 97% across the different regions, indicating widespread dissemination of the disease throughout the state. Dairy herds (OR = 2.85), larger herds (OR = 3.40), and the purchase of animals for breeding purposes (OR = 1.34) were identified as factors associated with EBL occurrence. The second chapter consisted of a cross-sectional study based on data from the bovine brucellosis surveillance program in the state of Santa Catarina, Brazil, to evaluate the occurrence of false-positive results obtained with the Milk Ring Test (MRT) and an indirect ELISA performed on bulk tank milk samples, as well as to investigate factors associated with disease occurrence at the herd level. A total of 924 dairy herds from 32 municipalities in the Chapecó region were included in the study. Bulk tank milk samples were initially tested using the MRT, and herds with positive results were subsequently tested by indirect ELISA. Herds that tested positive by ELISA underwent individual testing of all animals following the official protocol of the Brazilian National Program for the Control and Eradication of Brucellosis and Tuberculosis (Rose Bengal Test followed by the 2-mercaptoethanol test). Variables related to herd characteristics, animal movement, and the epidemiological context of the municipalities were also evaluated. The MRT yielded a false-positive rate of 90.04%, whereas the indirect ELISA showed a false-positive rate of 40.22%, demonstrating greater specificity for epidemiological surveillance purposes. Herd size was identified as a factor associated with disease occurrence. Overall, the findings expand current knowledge of the epidemiology of EBL in Minas Gerais and demonstrate the potential of indirect ELISA on bulk tank milk as a surveillance tool for bovine brucellosis, providing valuable evidence to support the development and improvement of control and eradication programs for these diseases.

MEMBROS DA BANCA:
Externo à Instituição - LUCIANA FARIA DE OLIVEIRA - IMA (Suplente)
Externo à Instituição - KARINA DINIZ BAUMGARTEN - USP (Membro)
Presidente - ELAINE MARIA SELES DORNELES (Membro)
Externo ao Programa - CHRISTIAN HIRSCH - DMV/FZMV (Membro)
Externo à Instituição - AMAURI ALCINDO ALFIERI - UEL (Membro)
Interno - ALESSANDRO DE SA GUIMARAES - EMBRAPA (Suplente)