Development of a real-time RT-PCR system applicable for rapid and pen-side diagnosis of foot-and-mouth disease using a portable device, PicoGene® PCR1100.

Foot-and-mouth disease (FMD) is a highly contagious viral vesicular disease, causing devastating losses to the livestock industry. A diagnostic method that enables quick decisions is required to control the disease, especially in FMD-free countries. Although conventional real-time reverse transcription polymerase chain reaction (RT-PCR) is a highly sensitive method widely used for the diagnosis of FMD, a time lag caused by the transport of samples to a laboratory may allow the spread of FMD. Here, we evaluated a real-time RT-PCR system using a portable PicoGene PCR1100 device for FMD diagnosis. This system could detect the synthetic FMD viral RNA within 20 min with high sensitivity compared to a conventional real-time RT-PCR. Furthermore, the Lysis Buffer S for crude nucleic extraction improved the viral RNA detection of this system in a homogenate of vesicular epithelium samples collected from FMD virus-infected animals. Furthermore, this system could detect the viral RNA in crude extracts prepared using the Lysis Buffer S from the vesicular epithelium samples homogenized using a Finger Masher tube, which allows easy homogenization without any equipment, with a high correlation compared to the standard method. Thus, the PicoGene device system can be utilized for the rapid and pen-side diagnosis of FMD.

Complete Genomic Characterization of Lumpy Skin Disease Virus Isolates from Beef Cattle in Lopburi Province, Central Thailand, during 2021-2022.

Lumpy skin disease (LSD) is a viral infection that impacts the cattle industry. The most efficient approach to prevent disease involves the utilization of live-attenuated LSD vaccines (LAVs), which stands out as the most successful method. However, LAVs might be subjected to changes to their genomes during replication that increase viral infectivity or virulence. The objective of this study was to monitor alterations in the genetic characteristics of the lumpy skin disease virus (LSDV) in beef cattle following the administration of LAVs in Lopburi Province of Central Thailand. A total of four skin samples from LSD cases were collected from non-vaccinated animals that exhibited LSD clinical symptoms from two distinct districts, spanning three subdistricts within the region. The samples of cattle were analyzed using real-time PCR targeting the LSDV074 p32 gene, the virus was isolated, and the entire genome sequences were evaluated through a single nucleotide polymorphisms (SNPs) analysis, and phylogenetic trees were assembled. The investigations revealed that LSDVs from two isolates from Chai Badan district exhibited significant mutations in the open reading frame (ORF) 023 putative protein, while another two isolates from Lam Sonthi district had a change in the untranslated region (UTR). For a result, the most proficient disease diagnosis and control should be evaluated on viral genetics on a regular basis.

Molecular epidemiological and serological studies of bovine leukemia virus (BLV) infection in Thailand cattle.

BLV is the etiological agent of enzootic bovine leucosis. BLV has negative effects on animal health and causes economic losses worldwide. However, epidemiological studies on BLV are relatively unknown in many parts of Asian countries. Thus, this study sought to explore BLV infections in cattle in Thailand to determine the extent of the geographic distribution of BLV and to measure its prevalence rates. For this study, 744 cattle from 11 farms in 9 provinces of Thailand were screened in 2013 and 2014 by ELISA and nested PCR. Of those cattle, 41 BLVs were genetically characterized using 188 BLV gp51 env gene sequences available in GenBank. The BLV prevalence in Thailand was high, ranging from 5.3% to 87.8%, as determined by PCR and 11.0% to 100% as determined by ELISA, according to geographical region. Phylogenetic analysis showed that Thailand BLVs belonged to genotypes 1 and 6 and a new genotype 10, which are sporadically observed across Thailand with a prevalence of 31.7%, 19.5%, and 48.8%, respectively. A significant number of amino acid substitutions were also found in the gp51 sequences, of which unique changes in genotype 10 have not been reported previously. Briefly, the majority of substitutions were confined to CD4+/CD8+ T-cell epitopes, neutralizing domains, and E-D-A epitopes. Those observations indicate that BLV infections in Thailand cattle are prevalent and that the geographic distribution of BLV is dynamic, with a high level of genetic diversity. This distribution implies a long-term BLV infection in cattle populations and the movement of infected cattle. In sum, this study suggests that intensive surveillance and effective prevention strategies are required to determine the prevalence of BLV in Thailand and control continuous infections with BLVs.