Molecular identification and characterization of Lumpy skin disease virus emergence from cattle in the northeastern part of Thailand

Detection and molecular characterization of lumpy skin disease and bovine papular stomatitis viruses in lumpy skin disease-suspected outbreaks in Tanzania

BACKGROUND

Lumpy Skin Disease (LSD) is endemic in sub-Saharan countries and is currently a global threat to the cattle industry. Information on the circulating Capripoxvirus lumpyskinpox, formerly known as Lumpy Skin Disease Virus (LSDV), and other poxviruses infecting cattle is very scant in Tanzania. The current study aimed to confirm and characterize LSDV and other poxviruses infecting cattle, from LSD suspected outbreaks in Tanzania.

METHODS

A total of 24 samples were collected from four LSD suspected outbreaks reported in Tanzania between February and May 2023. Samples were screened for LSDV genome by real-time PCR and then subjected to a high-resolution multiplex melting (HRM) assay where 10 samples were positive for Capripoxvirus (CaPV) and one sample was Parapoxvirus (PPV) positive. Four LSDV genes; RPO30, GPCR, EEV glycoprotein and B22R and the partial B2L gene of PPVs were analyzed.

RESULTS

All targeted LSDV genes from the Tanzanian isolates showed 100% similarity and isolates clustered with commonly circulating LSDV field isolates. Furthermore, the single nucleotide polymorphism (SNP) at position 240 (A-> G) of the EEV gene differentiates the Tanzanian LSDVs from the group of ancient Kenyan LSDV isolates while the B22R sequences of the Tanzanian LSDV isolates differed from the LSDV Neethling and LSDV KSGP-0240 derived vaccines. Sequence analysis of the partial B2L gene of the Tanzanian parapoxvirus bovinestomatitis, formerly known as Bovine papular stomatitis virus (BPSV) showed a different BPSV strain circulating compared to publicly available sequences.

CONCLUSION

These findings confirm the presence of LSDV in Tanzania, which suggesting the need for establishing an effective control program and continuous monitoring. The presence of a typical profile for Tanzania BPSV is an indication that, although never reported before, BPSV is established in the country therefore this virus should be included in the differential diagnosis of LSDV.

Epidemiology, genetic characterization and population structure analysis of lumpy skin disease virus from North India

Lumpy skin disease (LSD) is a transboundary, viral disease of cattle with a significant economic impact on the livestock industry. This study describes the epidemiological investigations of outbreaks of LSD that occurred in 2022 in three Indian states viz., Haryana, Himachal Pradesh and Rajasthan and the genetic characterization of Lumpy skin disease viruses (LSDVs). Also, the population structure analysis of LSDVs was carried out. Out of 138 scab samples tested from suspected cattle for LSDV, 106 were found positive. Of these, nine representative scab samples were further genetically characterized. Phylogenetic analysis based on the P32 and EEV gene sequences depicted that the LSDV strains of the present study had nucleotide identity of 100% and 99.10-99.45%, respectively with the LSDV/2019 field strains of India. Multiple sequence alignment of the EEV glycoprotein gene sequences revealed nucleotide polymorphisms at three positions viz., G178A, G253A and A459G in circulating LSDV/2022 field strains. Based on the median joining network analysis of the EEV gene, 12 haplotypes were identified among the LSDV populations. Population structure analysis corresponding to the EEV gene revealed high haplotype (0.8486 ± 0.026) and low nucleotide diversities (0.00636 ± 0.0006) and negative values for neutrality indices, indicating a high number of closely related haplotypes and the studied population may have undergone a recent expansion. The findings will help in understanding the distribution and dynamics of LSDV populations, which will prove pivotal in designing and implementing effective management and control strategies.

Characterization and molecular identification of the lumpy skin disease virus in cattle in the Mekong Delta of Vietnam

Background

Lumpy skin disease (LSD) is caused by a virus belonging to the genus Capripoxvirus, exhibiting clinical symptoms ranging from mild signs to the development of nodules. LSD emerged in Asia and Southeast Asia, including Vietnam, in October 2020 and has since spread throughout the region, resulting in productivity and economic losses.

Aim

This study aimed to investigate the virus-causing papular dermatitis in cattle from the Mekong Delta region of Vietnam by analyzing its GPCR gene and assessing its evolutionary relationship with sequences in the GenBank database.

Methods

Blood samples (n = 180) were collected from cattle farms in Ben Tre, Tien Giang, and Tra Vinh provinces. PCR targeting the P32 antigen gene was utilized to detect LSDV presence, and GPCR gene amplification was performed to assess genetic variability.

Results

LSDV was detected in 8.33% (15/180) of the samples using PCR targeting the P32 antigen gene. Each sample that tested positive for LSDV demonstrated complete amplification of the GPCR gene. Sequence alignments and phylogenetic analyses of the GPCR gene revealed that Mekong Delta LSDV isolates shared genetic similarities and possessed a 12-nucleotide insertion comparable to strains from China in 2019 and Northern Vietnam in 2020.

Conclusion

This study provides preliminary insights into the molecular characteristics of LSDV in cattle from the Mekong Delta region of Vietnam. The observed genetic relatedness to other LSDV sequences from Asia and Southeast Asia underscores the importance of regional surveillance and control measures. These findings contribute to the development of effective strategies for LSDV control and prevention.

Lumpy skin disease: history, current understanding and research gaps in the context of recent geographic expansion

Lumpy skin disease is recognized as a transboundary and emerging disease of cattle, buffaloes and other wild ruminants. Being initially restricted to Africa, and since 1989 the Middle East, the unprecedented recent spread across Eurasia demonstrates how underestimated and neglected this disease is. The initial identification of the causative agent of LSD as a poxvirus called LSD virus, was well as findings on LSDV transmission and epidemiology were pioneered at Onderstepoort, South Africa, from as early as the 1940s by researchers such as Weiss, Haig and Alexander. As more data emerges from an ever-increasing number of epidemiological studies, previously emphasized research gaps are being revisited and discussed. The currently available knowledge is in agreement with the previously described South African research experience that LSDV transmission can occur by multiple routes, including indirect contact, shared water sources and arthropods. The virus population is prone to molecular evolution, generating novel phylogenetically distinct variants resulting from a diverse range of selective pressures, including recombination between field and homologous vaccine strains in cell culture that produce virulent recombinants which pose diagnostic challenges. Host restriction is not limited to livestock, with certain wild ruminants being susceptible, with unknown consequences for the epidemiology of the disease.

Forecasting of daily new lumpy skin disease cases in Thailand at different stages of the epidemic using fuzzy logic time series, NNAR, and ARIMA methods

Lumpy skin disease (LSD) is an important transboundary disease affecting cattle in numerous countries in various continents. In Thailand, LSD is regarded as a serious threat to the cattle industry. Disease forecasting can assist authorities in formulating prevention and control policies. Therefore, the objective of this study was to compare the performance of time series models in forecasting a potential LSD epidemic in Thailand using nationwide data. For the forecasting of daily new cases, fuzzy time series (FTS), neural network auto-regressive (NNAR), and auto-regressive integrated moving average (ARIMA) models were applied to various datasets representing the different stages of the epidemic. Non-overlapping sliding and expanding window approaches were also employed to train the forecasting models. The results showed that the FTS outperformed other models in five of the seven validation datasets based on various error metrics. The predictive performance of the NNAR and ARIMA models was comparable, with NNAR outperforming ARIMA in some datasets and vice versa. Furthermore, the performance of models built from sliding and expanding window techniques was different. This is the first study to compare the forecasting abilities of the FTS, NNAR, and ARIMA models across multiple phases of the LSD epidemic. Livestock authorities and decision-makers may incorporate the forecasting techniques demonstrated herein into the LSD surveillance system to enhance its functionality and utility.

The genome sequence of lumpy skin disease virus from an outbreak in India suggests a distinct lineage of the virus

Although previously confined to regions within Africa, lumpy skin disease virus (LSDV) infections have caused significantly large outbreaks in several regions of the world in recent years. In 2019, an outbreak of the disease was reported in India with low rates of morbidity and no reported mortality. However, in 2022, an ongoing outbreak of LSDV spanning over seven states in India resulted in the loss of over 80,000 cattle over a period of three months. Here, we report complete genome sequences of six isolates of LSDV collected from affected cattle during an ongoing outbreak of the disease in Rajasthan, India. Analysis of these sequences showed that the genome isolates from the 2022 outbreak have a large number of genetic variations compared to the reference strain and that they form a distinct genetic lineage. This report thus highlights the importance of genome sequencing and surveillance of transboundary infectious agents to track the prevalence and emergence of variants.

Lumpy skin disease: A newly emerging disease in Southeast Asia

Lumpy skin disease (LSD) is caused by LSD virus (LSDV). This virus has been classified in the genus Capripoxvirus, family Poxviridae which generally affects large ruminants, especially cattle and domestic water buffalo. The first outbreak of LSD was found in 1929 in Zambia, then spreading throughout Africa and with an ongoing expanding distribution to Asia and Europe. In 2020, LSD was found from Southeast Asia in Vietnam and Myanmar before reaching Thailand and Laos in 2021. Therefore, LSD is a newly emerging disease that occurs in Southeast Asia and needs more research about pathology, transmission, diagnosis, distribution, prevention, and control. The results from this review show the nature of LSD, distribution, and epidemic maps which are helpful for further information on the control and prevention of LSD.