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


CONCLUSIONS
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.
Paixão
Tatiane A
TA
Departamento de Clínica e Cirurgia Veterinária, Escola de Veterinária da Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil. tatipaixao.vet@hotmail.com
Neta
Alcina V Carvalho
AV
Paiva
Naimes O
NO
Reis
Jorge R
JR
Barbosa
Meirivan S
MS
Serra
Claudia V
CV
Silva
René R
RR
Beckham
Tammy R
TR
Martin
Barbara M
BM
Clarke
Neville P
NP
Adams
L Garry
LG
Santos
Renato L
RL
D000818:Animals; D001938:Brazil; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis*; D005260:Female; D005536:Foot-and-Mouth Disease / Q000175:diagnosis*; D008297:Male; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary*; D012463:Saliva / Q000821:virology; D012680:Sensitivity and Specificity