Study of the temporal variation of the prevalence of porcine circovirus (PCV, PCV1, and PCV2) and porcine circovirus 2 (PCV2) genotypes in Brazil from 2009 to 2017

• Grant number: 17/13100-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2017
• End date: August 31, 2018
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Preventive Veterinary Medicine
• Principal Investigator: Taís Fukuta da Cruz
• Grantee: Camila Percário Rodrigues
• Host Institution: Instituto de Biociências (IBB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

Porcine circoviruses (PCV) belong to the family Circoviridae, genus Circovirus. PCV1 is considered to be a non-pathogenic virus, while PCV2 is associated with several diseases collectively referred to as porcine circovirus diseases (PCVD). When the commercial vaccines based on the PCV2a genotype appeared, disease control became effective, so vaccination is a widely used control and prevention measure in several countries, including Brazil. However, the concern with the emergence of PCV2 variants has increased, as PCV2 has a high rate of nucleotide substitution, keeping a rapid viral evolution. Thus, these characteristics favor the rapid emergence of viral mutants. Hence, for PCV2, five genotypes - PCV2a to PCV2e - have been described, and recently the genotype shift from PCV2b to PCV2d has been associated with cases of suspected vaccine failure in several countries. There are few studies about the detection of PCV and PCV2 genotypes in Brazil; therefore, this study aims to determine the temporal variation in the prevalence of PCV in whole blood samples (n = 16,346) of pigs from commercial farms in Brazil from April 2009 to May 2017 previously quantified by quantitative PCR (qPCR). Then, the whole blood samples (n = 387) positive for PCV by qPCR will be tested for PCV1, PCV2, genotypes PCV2a, PCV2b, and PCV2d by qPCR. The results of this study may assist in the prevention, control, and diagnosis of PCVD in Brazil, especially in relation to the emergence of PCV2 mutants due to vaccine failure. (AU)