Research article

Diagnosis of foot-and mouth disease by real time reverse transcription polymerase chain reaction under field conditions in Brazil

Tatiane A Paixão¹ , Alcina V Carvalho Neta¹ , Naimes O Paiva² , Jorge R Reis² , Meirivan S Barbosa² , Claudia V Serra³ , René R Silva² , Tammy R Beckham⁴ , Barbara M Martin⁵ , Neville P Clarke⁶ , L Garry Adams⁷ and Renato L Santos¹

¹  Departamento de Clínica e Cirurgia Veterinária, Escola de Veterinária da Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil

²  Laboratório Nacional Agropecuário – Pará, Belém, PA, Brazil

³  Laboratório Nacional Agropecuário – Minas Gerais, Pedro Leopoldo, MG, Brazil

⁴  Texas Veterinary Medical Diagnostic Laboratory, College Station, TX, USA

⁵  National Veterinary Services Laboratories, U.S. Department of Agriculture, Animal Plant Health Inspection Service, Center for Veterinary Biologics, Ames, IA, USA

⁶  National Center of Excellence for Foreign Animal & Zoonotic Diesease Defense, College Station, TX, USA

⁷  Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A&M University, College Station, TX, USA

author email corresponding author email

BMC Veterinary Research 2008, 4:53doi:10.1186/1746-6148-4-53

Published:	31 December 2008

Abstract

Background

Foot-and-mouth disease (FMD) is an economically important and highly contagious viral disease that affects cloven-hoofed domestic and wild animals. Virus isolation and enzyme-linked immunosorbent assay (ELISA) are the gold standard tests for diagnosis of FMD. As these methods are time consuming, assays based on viral nucleic acid amplification have been developed.

Results

A previously described real-time reverse transcriptase polymerase chain reaction (RT-PCR) assay with high sensitivity and specificity under laboratorial and experimental conditions was used in the current study. To verify the applicability of this assay under field conditions in Brazil, 460 oral swabs from cattle were collected in areas free of FMD (n = 200) and from areas with outbreaks of FMD (n = 260). Three samples from areas with outbreaks of FMD were positive by real-time RT-PCR, and 2 of those samples were positive by virus isolation and ELISA. Four other samples were considered inconclusive by real-time RT-PCR (threshold cycle [Ct] > 40); whereas all 200 samples from an area free of FMD were real-time RT-PCR negative.

Conclusion

real-time RT-PCR is a powerful technique for reliable detection of FMDV in a fraction of the time required for virus isolation and ELISA. However, it is noteworthy that lack of infrastructure in certain areas with high risk of FMD may be a limiting factor for using real-time RT-PCR as a routine diagnostic tool.