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Speed is paramount in the diagnosis of highly infectious diseases, such as foot-and-mouth
disease (FMD), as well as for emerging diseases; however, simplicity is required if a test
is to be deployed in the field. Recent developments in molecular biology have enabled the
specific detection of FMD virus (FMDV) by reverse-transcription loop-mediated isothermal
amplification (RT-LAMP), real-time reverse-transcription polymerase chain reaction (RT-
qPCR) and sequencing. RT-LAMP enables amplification of the FMDV RNA-dependent RNA
polymerase 3D(pol) gene at 63 °C (in the presence of a primer mixture and both reverse
transcriptase and Bst DNA polymerase) for 1 h, whilst RT-qPCR amplifies the same gene in
approximately 2 h 30 min. In this study, we compared the sensitivity and effectiveness of
RT-LAMP against RT-qPCR for the detection of the FMDV 3D(pol) gene in 179 oesophageal-
pharyngeal scraping samples (collected by probang) obtained from clinically healthy cattle
and buffalo in Malawi, Mozambique and Tanzania in 2010. The FMDV detection rate was
higher with RT-LAMP (30.2%; n = 54) than with RT-qPCR (17.3%; n = 31). All samples positive
by RT-qPCR (Cq ≤ 32.0) were also positive for the RT-LAMP assay; and both assays proved
to be highly specific for the FMDV target sequence. In addition, the VP1 sequences of 10
viruses isolated from positive samples corresponded to the respective FMDV serotypes and
genotypes. Our findings indicate that the performance of RT-LAMP is superior to RT-qPCR.
Accordingly, we consider this test to have great potential with regard to the specific detection
and surveillance of infectious diseases of humans and animals in resource-compromised
developing countries. |
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