Comparison of colorimetric loop-mediated isothermal amplification kit and reverse transcription-polymerase chain reaction in the diagnosis of peste des petits ruminants in sheep and goats in Southeast Nigeria

Research (Published online: 07-11-2020)

9. Comparison of colorimetric loop-mediated isothermal amplification kit and reverse transcription-polymerase chain reaction in the diagnosis of peste des petits ruminants in sheep and goats in Southeast Nigeria

Ijeoma Chekwube Chukwudi, Kenneth Ikejiofor Ogbu, Pam Dachung Luka, Refiloe Petunia Malesa, Livio Edward Heath, Emmanuel Ikenna Ugochukwu and Kennedy Foinkfu Chah

Veterinary World, 13(11): 2358-2363

ABSTRACT

Background and Aim: Peste des petits ruminants (PPR) is an acute, extremely contagious transboundary viral disease of small ruminants with severe economic consequences, caused by PPR virus. Cost-effective and rapid diagnosis of the disease is essential for prompt management and control. This study aimed to compare the application of a commercial colorimetric loop-mediated isothermal amplification (cLAMP) kit and reverse transcriptase-polymerase chain reaction (RT-PCR) in the diagnosis of PPR in sheep and goats in Southeast Nigeria.

Materials and Methods: Nasal swab samples were collected from West African Dwarf sheep and goats showing clinical signs suggestive of PPR (n=80) and those without any clinical signs (n=140) of the disease. The diagnosis was achieved through detection of PPR viral genome in the samples using a cLAMP kit and RT-PCR. cLAMP assay was done directly on nasal swab samples without ribosomal nucleic acid extraction. A set of six primers targeting the matrix gene protein was used for the cLAMP assay.

Results: PPR viral genome was detected by both cLAMP and RT-PCR in 51 (63.8%) of the 80 samples from sheep and goats with signs suggestive of PPR while 14 (10%) of those without signs tested positive for PPR by both assay methods. There was a 100% agreement in the cLAMP and RT-PCR results. However, cLAMP was a faster, easier, and less expensive method compared to RT-PCR.

Conclusion: The cLAMP assay demonstrates the potential for a point of care diagnosis in the field and a valuable diagnostic tool in areas with poor electricity supply as well as in a less equipped diagnostic laboratory. Since the reagents are affordable, cLAMP can be a diagnostic tool of choice in the detection and surveillance of PPR virus in countries with limited resources.

Keywords: colorimetric loop-mediated isothermal amplification, peste des petits ruminants virus, reverse transcription-polymerase chain reaction, small ruminant diagnostic tool.