Evaluation of the efficacy of live modified vaccines against Bovine Viral Diarrhea Virus (BVDV)

• Grant number: 21/02626-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2021
• End date: July 31, 2022
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Clinics and Surgery
• Principal Investigator: Viviani Gomes
• Grantee: Luana Camargo
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The objective of this research is to evaluate the efficacy of new commercially modified live vaccines against BVDV types 1 and 2 in comparison with inactivated vaccines. For this purpose, 30 Dutch heifers will be randomly distributed into five experimental groups: G1- modified live vaccine containing only BVDV-1 and BVDV-2; G2- modified live vaccine containing BVDV-1 and BVDV-2, in addition to BoHV-1, BPI3-V, BRSV, and Mannheimia haemolytica bacterin; G3- inactivated vaccine against BVDV types 1 and 2, in addition to BoHV-1, BPI3-V, BRSV, and Leptospira spp .; G4- inactivated recombinant vaccine against BVDV-1 and BVDV-2; G5- control group (placebo). Vaccine doses, revaccination, and administration routes will follow the manufacturers' recommendations. Blood samples will be collected on the day of vaccination (D0), revaccination (D30), and 30 days (D60) after the second dose of the vaccine. The measurement of specific antibodies against BVDV types 1 and 2 will be performed by means of Virus neutralization (VN) and ELISA (Enzyme-Linked Immunosorbent Assay) tests. The data will be parameterized to evaluate the effects of treatments and times, in addition to the interaction between time and treatment by the MIXED procedure (PROC-mixed, SAS). The seroconversion rate and the comparison of frequencies between groups will be performed using the chi-square test, and the comparison between times within each group using the Cochran Q test. The analyzes will be considered significant when Pd0.05. (AU)