Abstract:
The foot-and-mouth disease (FMD) is an economically important transboundary
animal disease (TADs) affecting all cloven-hoofed animals. It is caused by foot-and-
mouth disease virus (FMDV), which has seven antigenically distinct serotypes. FMD
is endemic in Tanzania, with outbreaks caused by predominantly five serotypes. In
order to improve the control of this disease, for instance using serotype-specific
vaccines, rapid detection and identification of circulating FMDV strains is of
paramount importance. This study describes the development and evaluation of a
reverse transcription loop- mediated isothermal amplification (RT-LAMP) assay for
diagnosis of serotype ‘O’ FMDV in endemic settings in Tanzania. A retrospective
study design was employed for this research whereby a total of forty-four (n=44)
archived epithelial tissue samples were analyzed by RNA extraction, reverse
transcription polymerase chain reaction (RT-PCR), RT-LAMP and DNA sequencing.
Primers for RT-LAMP targeting serotype ‘O’ FMDV isolates in Tanzania were
developed and found to optimally amplify the targeted gene at 65.0 ̊C for 45 minutes
in the presence of both Avian Myeloblastosis Virus (AMV) reverse transcriptase
enzyme and loop primers. The results indicated that RT-LAMP assay could amplify
the viral protein 1 (VP1) gene of serotype ‘O’ FMDV within a range of 13 to 26
minutes, with annealing temperatures of between 70.0 and 89.0°C. The findings
indicate that RT-LAMP assay is highly specific as no cross- reactivity occurred
between serotype ‘O’ primers with any of the other serotypes. The sensitivity as
indicated by the detection limit of the assay was deduced to be 3.78 ×10 -2 ng/μl. This
study concludes that RT-LAMP assay could be used to rapidly and accurately detect
VP1 gene of serotype ‘O’ FMDV from Tanzania. It is advisable that further studiesare required to evaluate the comparative sensitivity of the assay and check whether
the assay is field deployable. Further evaluation is also needed to determine whether
the assay would be useful for detecting serotype ‘O’ FMDV strains circulating in
other regions in Tanzania.
