Molecular characterisation of lumpy skin disease virus in Mahikeng local municipality

Abstract

Lumpy skin disease (LSD) is an infectious viral disease well-known to cause economic loss and reduced productivity in cattle. Several studies have addressed lumpy skin disease virus (LSDV) seroprevalence in cattle worldwide, including South Africa. Nevertheless, the prevalence of LSDV in Mahikeng Local Municipality (MLM) cattle, North West Province, is unknown. The study aimed to detect and identify LSDV from suspected cattle and those showing clinical symptoms. Approximately 200 samples (100 blood and 100 skin nodules biopsy) were collected from the animal with clinical manifestations with LSD. The serum neutralization test (SNT) method was used to detect antibodies of LSDV in the clinical samples. In addition, a Real-Time polymerase chain reaction high-resolution melt assay (RT-PCR)/ quantitative polymerase chain reaction (qPCR) and conventional polymerase chain reaction (PCR) was performed to genotype the LSDV strains. SNT results showed that out of 100 serum samples analyzed, 67% were positive for LSDV antibodies, while 33% were negative. The highest incidence occurred in Masutlhe (95%), followed by Tswaing (74%) and Meetmekaar (58%), respectively, whereas 50% of the positive samples were recorded in Lokaleng and 29% was reported in Six Hundred. Pearson Chi-Square revealed that there was a significant difference between the prevalence of LSDV in the villages of MLM (P˂0.05). Out of 100 skin nodules collected 16 samples showed a sufficient amount of DNA material. RT-PCR assay showed that all the 16 samples tested positive for LSDV. Conventional PCR assay resulted in amplification of the DNA samples showed bands at 1203 bp PCR product of G-protein-coupled chemokine receptor gene (GPCR), LSDV-022 gene at 237 bp and (thymidine kinase) TK gene (LSDV-066) at 400 bp. Nevertheless, sequencing results showed six samples (LSD-2-RSA-2018, LSD-3-RSA-2018, LSD-5-RSA-2018, LSD-9-RSA-2018, LSD-13-RSA-2018, and LSD-15-RSA- 2018) were positive to LSDV. Phylogenetic analyses for isolates were done using MEGA 7 and showed that the LSDV were firmly related to FJ869377 (Egypt-Isamalia 18/1989, KR024780 Turkey-02/2015, KY829023 Evros/GR/15, FJ 869375 RSA/06-D 19353-16, MH893760 LSDV Russian Dagestan 2015, KX894508 155920-Israel 2012, KX683219KSGP-0240 Kenya 1974 and AF 409137 NW-LW Warmbaths RSA 1999 strains. This study provided information on LSDV, which is in circulation in MLM, and this finding may help in developing effective prophylactic strategies in the villages affected by the virus.