Differentiation of sheep pox and goat poxviruses by sequence analysis and PCR-RFLP of P32 gene

An insight into emergence of lumpy skin disease virus: a threat to Indian cattle

Lumpy skin disease (LSD) is a highly infectious and economically devastating viral disease of cattle. It is caused by Lumpy Skin Disease Virus (LSDV) belonging to the genus Capripoxvirus and family Poxviridae. The origin of lumpy skin disease has been traced to Zambia, (an African nation) in Southern part during the year 1929. The first reported case of LSD besides Africa was from Israel, a Middle Eastern nation, thus proving inter-continental spread. Subsequently, the disease entered Middle East, Eastern Europe and Asia with numerous outbreaks in the recent years. LSD has emerged as a significant concern in the Indian sub-continent, due to outbreaks reported in countries such as Bangladesh, India, China in 2019. In the following years, other South and East Asian countries like Taipei, Nepal, Sri Lanka, Myanmar, Bhutan, Vietnam, Hong Kong, Thailand, Malaysia, Laos, Cambodia, Pakistan, Indonesia and Singapore also faced severe outbreaks. At present, LSD is considered to be an emerging disease in the Indian sub-continent due to the recent status of disease. Considering the global scenario, LSDV is changing its transmission dynamics as evidenced by a shift in its epidemiology. As a result of high morbidity and mortality rate among cattle, the current outbreaks have been a major cause of socio-economic catastrophe. This contagious viral disease has eminent repercussions as the estimated monetary damage incurred is quite high. Despite having networked surveillance and comprehensive databases, the recurring outbreaks have raised major concern among researchers. Therefore, this review offers brief insights into the emergence of LSDV by amalgamating the newest literature related to its biology, transmission, clinico-pathology, epidemiology, prevention strategies, and economic consequences. Additionally, we have also provided the epidemiological insights of the recent outbreaks with detailed state wise studies.

The complete genome sequence of Indian sheeppox vaccine virus and comparative analysis with other capripoxviruses

Sheeppox virus (SPPV) is responsible for a significant economic loss to sheep husbandry in enzootic regions of Africa, the Middle East, and Asia including the Indian subcontinent. In this study, we present the complete genome sequence of SPPV vaccine strain SPPV-Srin38/00 from India determined by next-generation sequencing (NGS) using Illumina technology. The attenuated Srinagar vaccine strain of SPPV (SPPV-Srin38/00) was developed by serial passaging the virus initially in lamb testes (LT) cells followed by Vero cell line. The SPPV-Srin38/00 virus has a genome size of 150, 103 bp, which encodes for 147 functional putative genes and consists of a central coding region flanked by two identical 2353 bp inverted terminal repeats (ITRs). Comparative phylogenetic analysis based on complete genome sequences of Capripoxviruses formed three distinct groups each for SPPV, GTPV, and LSDV with clustering of SPPV-Srin38/00 strain with SPPV-A strain. Nine ORFs of SPPV-Srin38/00 namely SPPV-Srin_002/SPPV-Srin_155, SPPV-Srin_004/SPPV-Srin_153, SPPV-Srin_009, SPPV-Srin_013, SPPV-Srin_026, SPPV-Srin_132, and SPPV-Srin_136 were found to be fragmented as compared to LSDV, whereas only one ORF (such as SPPV-Srin_136) was found to be fragmented as compared to GTPV. SPPV genomes, including the SPPV-Srin38/00 strain, shared 99.78-99.98% intraspecies nucleotide identity, indicating that SPPV strains have extremely low genetic diversity. The strain shared 96.80-97.08% and 97.11-97.61% nt identity with GTPV and LSDV strains, respectively. Its ORFs 016, 021, 022, 130 and 138 are the least identical ORFs among three species of the genus Capripoxvirus with 72.5-93% aa identity to GTPV and LSDV strains and may be potentially used for differentiation of CaPV species. This study may contribute to a better understanding of the epidemiology and evolution of capripoxviruses as well as the development of specific detection methods, better expression vectors, and vaccines with improved safety and efficacy.

Review of sheep and goat pox disease: current updates on epidemiology, diagnosis, prevention and control measures in Ethiopia

Sheep pox, goat pox, and lumpy skin diseases are economically significant and contagious viral diseases of sheep, goats and cattle, respectively, caused by the genus Capripoxvirus (CaPV) of the family Poxviridae. Currently, CaPV infection of small ruminants (sheep and goats) has been distributed widely and are prevalent in Central Africa, the Middle East, Europe and Asia. This disease poses challenges to food production and distribution, affecting rural livelihoods in most African countries, including Ethiopia. Transmission occurs mainly by direct or indirect contact with infected animals. They cause high morbidity (75-100% in endemic areas) and mortality (10-85%). Additionally, the mortality rate can approach 100% in susceptible animals. Diagnosis largely relies on clinical symptoms, confirmed by laboratory testing using real-time PCR, electron microscopy, virus isolation, serology and histology. Control and eradication of sheep pox virus (SPPV), goat pox virus (GTPV), and lumpy skin disease (LSDV) depend on timely recognition of disease eruption, vector control, and movement restriction. To date, attenuated vaccines originating from KSGPV O-180 strains are effective and widely used in Ethiopia to control CaPV throughout the country. This vaccine strain is clinically safe to control CaPV in small ruminants but not in cattle which may be associated with insufficient vaccination coverage and the production of low-quality vaccines.

Transboundary Animal Diseases, an Overview of 17 Diseases with Potential for Global Spread and Serious Consequences

Animals provide food and other critical resources to most of the global population. As such, diseases of animals can cause dire consequences, especially disease with high rates of morbidity or mortality. Transboundary animal diseases (TADs) are highly contagious or transmissible, epidemic diseases, with the potential to spread rapidly across the globe and the potential to cause substantial socioeconomic and public health consequences. Transboundary animal diseases can threaten the global food supply, reduce the availability of non-food animal products, or cause the loss of human productivity or life. Further, TADs result in socioeconomic consequences from costs of control or preventative measures, and from trade restrictions. A greater understanding of the transmission, spread, and pathogenesis of these diseases is required. Further work is also needed to improve the efficacy and cost of both diagnostics and vaccines. This review aims to give a broad overview of 17 TADs, providing researchers and veterinarians with a current, succinct resource of salient details regarding these significant diseases. For each disease, we provide a synopsis of the disease and its status, species and geographic areas affected, a summary of in vitro or in vivo research models, and when available, information regarding prevention or treatment.

Evidence of Transmission of Goatpox between Domestic Goats and Wild Himalayan Goral (Naemorhedus goral) in Arunachal Pradesh, India

Examination of carcasses of Himalayan goral (Naemorhedus goral) revealed nodular, pox-like eruptions in the skin. Similar disease was also seen in domestic goats (Capra aegagrus hircus) in the same area. Goatpox virus was identified as the etiology of the disease in both cases, with probable transmission between the species.

Lumpy skin disease in cattle in Sharkia, Egypt: epidemiological and genetic characterization of the virus

Lumpy skin disease virus (LSDV) continues to threaten the cattle industry in Egypt. This survey investigated the epidemiological risk factors and the genetic characterization of circulating strains by partial sequencing of the P32 gene on cattle farms in the Sharkia Governorate, Egypt. Out of 600 cattle examined, morbidity, mortality, and case fatality were 31.2%, 1.8%, and 5.9%, respectively. Risk of LSD was higher among unvaccinated cattle kept outdoors compared to vaccinated cattle kept indoors, and the prevalence rates were statistically significantly different (P < 0.05). Regarding seasonal distribution, the highest number of cases was in June and July, and the lowest was in November. The P32 gene sequences showed that two LSDV isolates were 100% identical and 99.26% identical with 2017 Russian LSDV. Phylogenetic analysis revealed that two local isolates in this study were grouped together with other LSDVs from Russia (Saratov), Kenya, Greece, and Israel. The sequences in the study and other Egyptian sequences were grouped into two clusters with low genetic divergence, indicating that different strains are spreading in Egypt and that LSDV is more genetically related to sheep poxviruses than goat poxviruses. Our study confirms the necessity of evaluating the vaccination strategy adopted in Egypt, and sequence analysis based on the P32 gene is appropriate for genetic epidemiological studies of the local LSDVs.

Probe-Based Real-Time qPCR Assays for a Reliable Differentiation of Capripox Virus Species

Outbreaks of the three capripox virus species, namely lumpy skin disease virus, sheeppox virus, and goatpox virus, severely affect animal health and both national and international economies. Therefore, the World Organization for Animal Health (OIE) classified them as notifiable diseases. Until now, discrimination of capripox virus species was possible by using different conventional PCR protocols. However, more sophisticated probe-based real-time qPCR systems addressing this issue are, to our knowledge, still missing. In the present study, we developed several duplex qPCR assays consisting of different types of fluorescence-labelled probes that are highly sensitive and show a high analytical specificity. Finally, our assays were combined with already published diagnostic methods to a diagnostic workflow that enables time-saving, reliable, and robust detection, differentiation, and characterization of capripox virus isolates.

Differentiation of Capripox Viruses by Nanopore Sequencing

The genus capripoxvirus (CaPV), family Poxviridae, includes three virus species: goatpox virus (GPV), sheeppox virus (SPV) and lumpy skin disease virus (LSDV). CaPV causes disease outbreaks with consequent economic losses in Africa and the Middle East. LSDV has recently spread to Southeast Europe. As CaPVs share 96–97% genetic similarity along the length of the entire genome and are difficult to distinguish using serological assays, simple, reliable and fast methods for diagnosis and species differentiation are crucial in cases of disease outbreak. The present study aimed to develop a field-applicable CaPV differentiation method. Nanopore technology was used for whole genome sequencing. A local database of complete CaPV genomes and partial sequences of three genes (RPO30, P32 and GPCR) was established for offline Basic Local Alignment Search Tool (BLAST). Specificities of 98.04% in whole genome and 97.86% in RPO30 gene runs were obtained among the three virus species, while other databases were less specific. The total run time was shortened to approximately 2 h. Functionality of the developed procedure was proved by samples with high host background sequences. Reliable differentiation options for the quality and capacity of hardware, and sample quality of suspected cases, were derived from these findings. The whole workflow can be performed rapidly with a mobile suitcase laboratory and mini-computer, allowing application at the point-of-need with limited resource settings.

Lumpy skin disease outbreaks investigation in Egyptian cattle and buffaloes: Serological evidence and molecular characterization of genome termini

Lumpy skin disease (LSD) is an endemic highly infectious viral disease affecting cattle in Egypt. This study aimed to identify and characterize the LSD virus (LSDV) outbreaks in Egypt between 2016 and 2018 and to determine the role of Egyptian buffaloes in the epidemiology of LSD. A total of 44 skin biopsies (41 from cattle and 3 from buffaloes) and 31 blood samples from asymptomatic buffaloes in contact with clinically infected cattle were collected from 7 Egyptian governorates and tested by real-time (rt)-PCR. The positive samples were further isolated, and the isolates were analyzed by conventional PCR to amplify the LSDV001 and LSDV002 genes; three isolates were sequenced, and the phylogenetic tree was constructed. In addition, 198 serum samples (102 from cattle and 96 from contact buffaloes) were examined using ELISA. Out of 44 skin nodules analyzed by rt-PCR, 31 (70.45 %) were positive while, non of the buffalo samples were positive. Out of 31 positive rt-PCR samples, LSDV was isolated on CAM (n=19; 61.29%) and MDBK cell culture. The virus isolates were confirmed by conventional PCR where 1237 bp product size was successfully amplified. The phylogenetic analysis of LSDV002 gene revealed that three sequenced LSDV isolates were identical to each other and to LSDV isolates from different countries in Africa, Asia, and Europe with 99-100 % identity. ELISA analyses showed seroreactivity of LSDV in Egyptian cattle and buffaloes. In conclusion, the Egyptian water buffalo serves as an accidental non-adapted host for the disease and this point requires more deep investigation. In addition, the current vaccine strategy should be re-evaluated for more coverage and effectiveness.

Molecular phylogenetics of a recently isolated goat pox virus from Vietnam

Background

After a decade of silence, an outbreak of the contagious and Asian endemic disease, goat pox re-emerged in North Vietnam affecting more than 1800 heads with a mortality rate of 6.5%. The inevitable impact of goat pox on hide quality, breeding, chevon and milk production has resulted in a significant economic losses to the developing goat industry of Vietnam. In the act of establishing an effective control of this devastating disease, tracing the source of re-emergence via a phylogenetic study was carried out to reveal their genetic relatedness. Either skin scab or papule from the six affected provinces were collected, cultured into Vero cells followed by restricted enzyme digestion of targeted P32 gene DNA encoding. The P32 gene was then cloned and transformed into E.coli competent cells for further sequencing.

Results

The isolated sequence is deposited into GenBank under Accession No. MN317561/VNUAGTP1. The phylogenetic tree revealed high similarity of nucleotide and amino acid sequences to references goat pox strains accounting for 99.6 and 99.3, respectively. The Vietnamese strain is clustered together with currently circulating goat pox virus in China, India and Pakistan which suggested the origin of South China.

Conclusions

This Vietnam isolate is clustered together with other Asian goat pox strains indicating the dissemination of a common goat pox virus within this continent.

Molecular characterization of lumpy skin disease virus (LSDV) emerged in Bangladesh reveals unique genetic features compared to contemporary field strains

Background

Lumpy skin disease (LSD) is a contagious viral disease of cattle caused by lumpy skin disease virus (LSDV). LSD has recently spread in Asia following outbreaks in the Middle East and Europe. The disease emerged in Bangladesh in July 2019 in the Chattogram district, then rapidly spread throughout the entire country. We investigated six LSD outbreaks in Bangladesh to record the clinical signs and collect samples for diagnostic confirmation. Furthermore, we performed the molecular characterization of Bangladesh isolates, analyzing the full RPO30 and GPCR genes and the partial EEV glycoprotein gene.

Results

Clinical observations revealed common LSD clinical signs in the affected cattle. PCR and real-time PCR, showed the presence of the LSDV genome in samples from all six districts. Phylogenetic analysis and detailed inspection of multiple sequence alignments revealed that Bangladesh isolates differ from common LSDV field isolates encountered in Africa, the Middle East, and Europe, as well as newly emerged LSDV variants in Russia and China. Instead, they were closely related to LSDV KSGP-0240, LSDV NI2490, and LSDV Kenya.

Conclusions

These results show the importance of continuous monitoring and characterization of circulating strains and the need to continually refine the strategies for differentiating vaccine strains from field viruses.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-02751-x.

Molecular phylogeny of Capripoxviruses based on major immunodominant protein (P32) reveals circulation of host specific sheeppox and goatpox viruses in small ruminants of India

Sheeppox and goatpox are highly contagious viral diseases of small ruminants causing severe economic losses to the livestock farmers. The disease is enzootic in Asia including India, Middle East and African countries. In the present study, a total of 28 isolates from twenty five sheeppox and goatpox disease outbreaks were phylogenetically analyzed based on P32 gene/protein along with homology modeling and docking using heparan sulfate and UDP-glucose. Three distinct lineage-specific clusters as per their host origin were recorded. Multiple sequence analysis of P32 gene revealed that genetically similar sheeppox virus (SPPV) and goatpox virus (GTPV) strains are circulating in India. Phylogenetically, Lumpy skin disease (LSDV) and SPPV had a closer genetic relationship than GTPV. Comparative sequence alignment indicated conservation of various motifs such as glycosaminoglycan (GAG), chemokine like motif (CX3C) and Asp-Glu-any other residue-Asp (D/ExD), as well as viral specific signature residues in SPPV and GTPV isolates. Structurally, P32 protein of SPPV and GTPV with mixed α helices and β sheets resembled with crystal structure of homologue vaccinia virus H3L protein. Docking studies in P32 protein of SPPV and GTPV revealed conserved binding pattern with heparan sulfate which is involved in the virus attachment and varied glycosyltransferase fold with UDP-glucose. These findings may help in development of suitable vaccines/diagnostics and therapeutics against capripoxviruses.

Comparative sequence and structural analysis of the ORF095 gene, a vaccinia virus A4L homolog of capripoxvirus in sheep and goats

Sheeppox and goatpox are important transboundary animal viral diseases of sheep and goats caused by sheeppox virus (SPPV) and goatpox virus (GTPV), respectively, of the genus Capripoxvirus, family Poxviridae. Among the proteins encoded by the capripoxvirus (CaPV) genome, ORF095 (vaccinia virus A4L homolog) is an immunodominant virion core protein that plays a pivotal role in virus assembly and morphogenesis. In the present study, sequence analysis of the ORF095 genes of 27 SPPV and GTPV isolates or field samples from different geographical regions of India was performed, and structure was prediction was done by homology modeling. A multiple sequence alignment of different CaPV isolates revealed that CaPV-A4L is highly conserved, with several species-specific signature residues, namely A93, A216, A315, G136 and G146 in GTPV, G47, A63, A168 and A276 in SPPV, and G48 and C98 in lumpy skin disease virus (LSDV). Phylogenetically, the CaPV isolates were separated into three major clusters, GTPV, SPPV and LSDV, based on the complete coding sequence of the CaPV-A4L gene. Genus-specific clustering of poxviruses was observed in phylogenetic analysis based on A4L protein homologs of chordopoxviruses. A secondary structure prediction showed the presence of six α-helices and one β-sheet as well as some coils. The signature residues identified here are potentially useful for genotyping, and the predicted characteristics of the CaPV-A4L protein make it an ideal candidate for use as an immunogenic or diagnostic antigen for the development of immunoassays in  the sero-evaluation of CaPV in target hosts.

Tetra-primer amplification refractory mutation system-polymerase chain reaction (TARMS-PCR) assay in genotyping of single nucleotide polymorphism in goatpox virus p32 gene

Single nucleotide polymorphisms (SNPs) are most often associated with some pathological implications. Screening out the presence of such mutations is extremely sought to know the nature of the disease outbreak. Furthermore, the allele specific distributions of the virus are to be known for effective epidemiological strategies. Tetra-primer amplification refractory mutation system-polymerase chain reaction (TARMS-PCR) is a simple, rapid and inexpensive technique as compared to high thoroughput sequencing methods for genotyping SNPs. In the present report, a novel TARMS-PCR was utilized to ascertain the presence of a particular allele (645GTPVC/T) in the p32 gene of goatpox virus (GTPV), one of the most widespread Capripoxvirus affecting small ruminants exhibiting moderate to even severe pathological consequences in the endemic areas. It was found that GTPV of Chinese origin are GTPVC/T type whereas only single genotype (GTPVT) was found among GTPV of Indian origins. Possibly, this is the first report of development of a TARMS-PCR technique for genotyping of virus to ascertain the presence of a specific allele. This technique can be applied further to unveil the presence of deleterious mutations in any other viral genome. Further, this technique can be applied for cross-border surveillance of GTPV among China and India.

Molecular and histopathological confirmation of clinically diagnosed lumpy skin disease in cattle, Baghdad Province of Iraq

Aim:

This study aimed to confirm the clinically diagnosed cattle with lumpy skin disease (LSD) at Baghdad Province/Iraq from October 2018 to March 2019.

Materials and Methods:

Molecular polymerase chain reaction (PCR) and histopathology were applied for the detection of LSD among 71 infected cattle issued for slaughter.

Results:

Pre-slaughter clinical examination showed significant increases (p<0.05) in values of temperature (39.7±0.74°C), pulse (96.42±3.51), and respiratory (33.54±0.63) rates. Enlargement of lymph nodes (prescapular, supramammary, and prefemoral), lacrimation, mucopurulent nasal discharge, salivation, edema in limbs and head among severe infected cases, and marked fall in milk production was seen. An association of LSD to risk factors (age, gender, and areas) showed that there is significant elevation in prevalence of disease in >2-5 years (54.93%) rather than other age groups (>5 and <2 years)in females (73.24%) than males (26.76%); and in sub-rural (42.25%) and rural (39.44%) compared to urban (18.31%) areas. Postmortem examination appeared nodular lesions in upper parts of the digestive system (9.86%), rumen (2.82%), upper respiratory tracts (7.04%), and lung (4.23%). The PCR examination of P32 and thymidine kinase antigenic genes showed 90.14% and 60.56% positive samples, respectively. Histopathological analysis of nodular skin biopsies showed edema, hyperemia, acanthosis, severe hydropic degeneration, and hyperkeratosis in epidermis; whereas, mononuclear cell infiltration, inclusion bodies, and vasculitis seen in the dermis.

Conclusion:

PCR and histopathology assay could be a potential method to confirm the LSD infection concomitant with clinical examination.

Overview of diagnostic tools for Capripox virus infections

Capripox viruses are the causative agents of important animal diseases in cattle (Lumpy Skin Disease), sheep (Sheeppox) and goats (Goatpox) with severe socio-economic impact in case of wide scale outbreaks. Therefore there is a constant need for adequate diagnostic tools. The assays must be fit-for-purpose to identify the virus quickly and correctly and to be useful for surveillance and monitoring at different stages of an epidemic. Different diagnostic performance characteristics are required depending on the situation and the test purpose. The need for high throughput, high specificity/sensitivity and the capability for differentiating field virus strains from vaccine strains drives the development of new and better assays preferably with an advantageous cost-benefit balance. This review aims to look at existing and new virological and serological diagnostic tools used in the control against diseases caused by Capripox viruses.

Development of a multiplex TaqMan qPCR assay for simultaneous detection and differentiation of four DNA and RNA viruses from clinical samples of sheep and goats

Mixed infections with different pathogens are common in sheep and goats under intensive production conditions. Quick and accurate detection and differentiation of different pathogens is necessary for epidemiological surveillance, disease management and import and export controls. Multiplex TaqMan qPCR protocols were developed and subsequently evaluated as effective tools in simultaneously detecting single and mixed infections in sheep and goats. Four pairs of primers and four probes labeled with Rox/BHQ2, Cy5/BHQ2, Hex/BHQ1 and Fam/BHQ1 for peste des petits ruminants virus (PPRV), foot and mouth disease virus (FMDV), goat pox virus (GTPV) and orf virus (ORFV), respectively, were used in the multiplex TaqMan qPCR assay. The assay was shown to be sensitive with detection limits of 9.17 × 10¹, 1.69 × 10², 9.41 × 10¹ and 7.46 × 10¹ copies/μL for PPRV, FMDV, GTPV and ORFV from a mixture of four viruses in a reaction, respectively. The assay was highly specific in its ability to detect one or more viruses in various combinations in the specimens. 38 clinical samples collected from sheep and goats were detected among 43 samples tested by multiplex TaqMan qPCR, showing highly effective identification. Overall, the multiplex TaqMan qPCR panel provides a fast, specific, and sensitive diagnostic tool for the accurate detection of multiple viral pathogens in sheep and goats.

VARV B22R homologue as phylogenetic marker gene for Capripoxvirus classification and divergence time dating

Sheeppox disease is associated with significant losses in sheep production world over. The sheep pox virus, the goatpox virus, and the lumpy skin disease virus cannot be distinguished by conventional serological tests. Identification of these pathogens needs molecular methods. In this study, seven genes viz. EEV maturation protein-F12L, Virion protein-D3R, RNA polymerase subunit-A5R, Virion core protein-A10L, EEV glycoprotein-A33R, VARV B22R homologue, and Kelch like protein-A55R that cover the start, middle, and end of the genome were selected. These genes were amplified from Roumanian-Fanar vaccine strain and Jaipur virulent strain, cloned, and sequenced. On analysis with the available database sequences, VARV B22R homologue was identified as a marker for phylogenetic reconstruction for classifying the sheeppox viruses of the ungulates. Further, divergence time dating with VARV B22R gene accurately predicted the sheeppox disease outbreak involving Jaipur virulent strain.

Goatpox outbreak at a high altitude goat farm of Mizoram: possibility of wild life spill over to domestic goat population

In this study, pox-like outbreaks in goat population was investigated that occurred in a high altitude goat farm located in Mizoram, a hilly state of North eastern India. The outbreak initially involved the serows, an wild animal belonging to the family Bovidae, subfamily Caprinae and genus Capricornis, the state animal of Mizoram. Later, the disease affected the domestic goat population. The disease was diagnosed on the basis of gross lesions and PCR amplification of partial P32 gene of capripox virus. The virus was isolated in vero cells. The full length P32 gene was sequenced and phylogenetic tree was constructed. It was revealed that the capripox virus isolated from the outbreak was closely related to the Chinese strain of goatpox virus at both amino acid and nucleotide level. To the authors' knowledge, this is the first report on isolation and characterization of capripoxvirus from north eastern region of India.

Phylogenetic analysis of the lumpy skin disease viruses in northwest of Iran

Lumpy skin disease (LSD) is a devastating viral disease of cattle which has recently spread from Africa into the countries of the Middle East. The aim of the present study was to investigate the relationships among lumpy skin disease viruses (LSDV) isolated from different regions of Iran and the origin and spread of these viruses. In this study, a total of 234 blood samples from clinically affected animals from four provinces in the northwest of Iran were screened for LSDV using polymerase chain reaction (PCR). From 80 positive samples for LSDV detected by PCR, the partial P32 gene (759 bp) of 12 isolates were sequenced and phylogenetically analyzed. LSD viruses were grouped in three subclusters with an overall 97.1-100% nucleotide identity. LSDVs isolated from Gilan showed lowest nucleotide identity with the other LSDVs. Four isolates of LSDV including KO-1, EA-1, EA-3, and WA-3 showed 100% similarity with each other and also with the Neethling strain. Phylogenetic analysis indicated that the identified LSDVs were closely related to each other and had high-sequence homology with other LSDV isolates from Africa. It was concluded that LSD outbreak probably occurred in the northwest of Iran by LSDVs entering the country from Iraq and P32 nucleotide sequence information obtained in the present study is a valuable resource in understanding the genetic nature and molecular epidemiology of local LSDV isolates which can be used for future vaccine development based on the circulating strains in the region.

Phylogenetic analysis of sheep pox virus (SPPV) virion core protein P4a gene revealed extensive sequence conservation among capripox viruses

In the present study, virion core protein P4a gene was PCR amplified from sheep pox virus (SPPV) Jaipur isolate and Roumanian Fanar (RF) vaccine strain adapted and propagated in lamb testis/vero cells. Gene specific primers were designed for amplification of P4a gene. Amplified P4a gene fragment was sequence characterized and 808 bp sequence was compared across SPPV, GTPV and LSDV isolates available in GenBank database which revealed extensive sequence conservation of 97% to 100% within pox virus groups. Sheep pox virus Jaipur isolate was found closely placed with Roumaninan Fanar (RF) and TU isolates. Further, phylogenetic analysis of P4a gene sequence indicated three distinct clusters of Capripox viruses with GTPV interestingly placed closely to LSDV group.

Molecular epidemiology of goat pox viruses

Goat pox disease outbreaks were observed in different places affecting Black Bengal Goats in West Bengal (WB) and Tellicherry, Vembur and non-descriptive breeds in Tamil Nadu (TN) causing severe lesions and mortality up to 30%. Clinical specimens from all the outbreaks were screened by polymerase chain reaction followed by restriction fragment length polymorphism (PCR-RFLP) and confirmed the diseases as Goat Pox. Virus isolation in Vero cell line was done with randomly selected ten samples, cytopathic effects (CPE) characterized by syncytia and intracytoplasmic inclusion bodies were observed after several blind passages. Nucleotide sequence of complete p32 gene using randomly selected two isolates and three clinical specimens revealed presence of Goat pox virus (GTPV)-specific signature residues in all the sequences. Phylogenetic analysis using the present five sequences along with GenBank data of GTPV complete p32 gene sequences showed all the GTPV sequences cluster together except Pellor strain (NC004003) and FZ Chinese strain (KC951854). The five sequences either from WB or TN cluster more closely with GTPV isolates of Maharashtra state that were responsible for cross species outbreak of pox disease in both sheep (KF468759) and goats (KF468762) in India during the year 2010. All the Indian goat pox viruses, including the Mukteswar strain, isolated in 1946 and sequence reported in 2004 clustered together with the GTPVs causing the recent outbreaks. It was observed that GTPVs caused similar clinical manifestation irrespective of their geographical locations and breed characteristics, no variation observed among the Indian isolates based on p32 gene over the period of seventy years and disease outbreaks could not be observed or reported in vaccinated goats.

Development and validation of a TaqMan probe-based real-time PCR method for the differentiation of wild type lumpy skin disease virus from vaccine virus strains

Lumpy skin disease (LSD) is a transboundary viral disease of cattle with severe economic impact. Immunization of cattle with homologous live attenuated vaccines poses a number of diagnostic problems, as it has been associated with adverse reactions resembling disease symptoms. The latter hampers clinical diagnosis and poses challenges in virus identification. To this end, a duplex quantitative real-time PCR method targeting the GPCR gene was developed and validated, for the concurrent detection and differentiation of wild type and vaccine Lumpy skin disease virus (LSDV) strains. The method was evaluated in three laboratories. The evaluation included a panel of 38 poxvirus isolates/strains and the analytical characteristics of the method were determined. Amplification efficiencies were 91.3% and 90.7%, for wild type and vaccine LSDV, respectively; the limit of detection was 8 DNA copies for both targets and the inter-assay CV was 0.30% for wild type and 0.73% for vaccine LSDV. The diagnostic performance was assessed using 163 LSDV-positive samples, including field specimens and samples from experimentally vaccinated/infected animals. The method is able to confirm diagnosis in suspect cases, it differentiates infected from vaccinated animals (DIVA) and can be regarded as an important tool for effective LSD surveillance and eradication during vaccination campaigns.

Development of multiplex PCR for simultaneous detection and differentiation of six DNA and RNA viruses from clinical samples of sheep and goats

Multiplex reverse transcription-polymerase chain reaction (RT-PCR) and PCR protocols were developed and subsequently evaluated for its effectiveness in detecting simultaneously single and mixed infections in sheep and goats. Specific primers for three DNA viruses and three RNA viruses, including foot and mouth disease virus (FMDV), Bluetongue virus (BTV), peste des petits ruminants virus (PPRV), sheeppox virus (SPPV), goatpox virus (GTPV) and orf virus (ORFV) were used for testing procedure. A single nucleic acid extraction protocol was adopted for the simultaneous extraction of both RNA and DNA viruses. The multiplex PCR consisted with two-step procedure which included reverse transcription of RNA virus and multiplex PCR of viral cDNA and DNA. The multiplex PCR assay was shown to be sensitive because it could detect at least 100pg of viral genomic DNA or RNA from a mixture of six viruses in a reaction. The assay was also highly specific in detecting one or more of the same viruses in various combinations in specimens. Thirty seven clinical samples collected from sheep and goats were detected among forty three samples tested by both uniplex and multiplex PCR, showing highly identification. As results of the sensitivity and specificity, the multiplex PCR is a useful approach for clinical diagnosis of mixed infections of DNA and RNA viruses in sheep and goats with a reaction.

Real-Time PCR Assays for the Specific Detection of Field Balkan Strains of Lumpy Skin Disease Virus

Lumpy skin disease (LSD) is an important disease of cattle which is included in the OIE list of notifiable terrestrial animal diseases because of its great economic importance. The etiological agent is the Lumpy skin disease virus (LSDV).

In the control of LSD attenuated strains of LSDV and SPPV are successfully used as vaccine strains in infected areas. In the case of vaccination policy, due to the possibility of mild or systemic post-vaccination reactions in vaccinated animals, the application of diagnostic procedures that will rapidly and specifically differentiate LSDV field strains from LSD vaccine virus strains are extremely important. Rapidity in diagnostics and disposal of infected animals is one of the key factors in the prevention of spreading the disease.

In the presented study we have described the development and validation of two real-time TaqMan-PCR assays for a rapid, sensitive and specific detection of the virulent field LSDV strain currently circulating in the Balkan Peninsula. Specificity for the field strain and exclusivity for vaccine strains was tested on 171 samples from naturally infected and vaccinated animals.

The results of this study show that both developed real-time PCR assays are more sensitive than the conventional nested PCR in detecting field LSDV strains thus enabling rapid and high-throughput detection of animals infected with field strains of LSDV.

In conclusion, both KV-2 and FLI real-time PCR assays described in this study are simple, rapid, sensitive and suitable for routine use in a diagnostic laboratory and have the potential to replace conventional nested gel-based PCR assays as the standard procedure for the detection of field strains of LSDV in clinical samples.

Detection, identification, and differentiation of sheep pox virus and goat pox virus from clinical cases in Giza Governorate, Egypt

AIM

To isolate, identify, and differentiate Capripoxviruses (CaPV) (sheep pox virus and goat pox virus) infections by egg inoculation, transmission electron microscopy (TEM), and 30 kDa RNA polymerase subunit gene-based polymerase chain reaction (PCR) (RPO30) in clinically affected animals in Hawamdia township of Giza Governorate, Egypt.

MATERIALS AND METHODS

A total of 37 scab samples were collected from clinically suspected field cases of sheep pox and goat pox. These samples were collected during (2014-2015) during different outbreaks of sheep pox and goat pox from Hawamdia township of Giza Governorate, Egypt. The samples were subjected to egg inoculation, TEM, and (RPO30) gene-based PCR. By using the egg inoculation: Previously prepared 37 scab samples (n=23 sheep and n=14 goats) were inoculated on the chorioallantoic membrane of specific pathogen free (SPF) embryonated chicken eggs (12 days old age). In the presence of the suitable percentage of humidity and candling, the inoculated eggs were incubated at 37°C. By using the TEM: Samples showed positive pock lesions on the chorioallantoic membranes, were fixed in glutaraldehyde, then processed and sectioned for TEM. Using the (RPO30) gene-based PCR assay, 30 of positive samples after egg inoculation (n=19 sheep and n=11 goats) were screened.

RESULTS

Using the egg inoculation, a characteristic pock lesions for poxviruses were seen in 30/37 (n=19 sheep and n=11 goats) (81.08%). Using the TEM, examination of the positive samples after egg inoculation revealed positive result in 23/30 (n=15 sheep and n=8 goats) (76.66%). The positive results represented by the presence of negatively stained oval-shape virus particles. Using the (RPO30) gene-based PCR assay, out of 30 total of positive samples after egg inoculation (n=19 sheep and n=11 goats) were screened, 27 (90%) samples (n=17 sheep and n=10 goats) were positive. The given band sizes of sheep and goats were 172 and 152 bp, respectively.

CONCLUSION

PCR assay depended on RPO30 gene can be used lonely for the detection, identification, and differentiation of CaPVs. RPO30 gene-based PCR assay in combination with gene sequencing helps in molecular epidemiological studies of CaPV infection.

Identification and functional analysis of the GTPV bidirectional promoter region

The goat pox chick embryo-attenuated virus (GTPV) has been developed as an effective vaccine that can elicit protective immune responses. It possesses a large genome and a robust ability to express exogenous genes. Thus, this virus is an ideal vector for recombinant live vaccines for infectious diseases in ruminant animals. In this study, we identified a novel bidirectional promoter region of GTPV through screening named PbVV(±). PbVV(±) is located between ETF-l and VITF-3, which are transcribed in opposite directions. A new recombinant goat pox virus (rGTPV) was constructed, in which duplicate PbVV(+) was used as a promoter element to enhance Brucella OMP31 expression, and duplicate PbVV(-) was used as a promoter element to regulate enhanced green fluorescent protein (EGFP) at the same time as the selection marker. PbVV(-) promoter activity was compared to that of the P7.5 promoter of vaccinia virus, as measured by EGFP expression; the fluorescence intensity of EGFP expressed in cells was confirmed by fluorescence microscopy and flow cytometry. PbVV(+) promoter activity was measured by Brucella OMP31 expression. Interaction with the anti-Brucella-OMP31 monoclonal antibody was confirmed by western blotting, and OMP31 mRNA expression was assessed by qRT-PCR. The results of this study will be useful for the further study of effective multivalent vaccines based on rGTPV. This study also provides a theoretical basis for overcoming the problem of low expression of exogenous genes.

Development and evaluation of loop-mediated isothermal amplification assay for rapid detection of Capripoxvirus

Aim:

The present study was undertaken to develop a nucleic acid-based diagnostic assay loop-mediated isothermal amplification assay (LAMP) targeting highly conserved genomic regions of Capripoxvirus (CaPVs) and its comparative evaluation with real-time polymerase chain reaction (PCR).

Material and Methods:

Lyophilized vaccine strain of sheeppox virus (SPPV) was used for optimization of LAMP assay. The LAMP assay was designed using envelope immunogenic protein (P32) coding gene targeting highly conserved genomic regions of CaPV responsible for causing sheep pox, goat pox, and lumpy skin disease in sheep, goat and cattle respectively. Serial tenfold dilution of SPPV recombinant plasmid DNA was used for a calculating limit of detection. Analytical sensitivity and specificity were performed.

Results:

The test described is quick (30 min), sensitive and specific for detection of CaPVs. The described assay did not show any cross-reactivity to other related viruses that cause apparently similar clinical signs. It was found to be ten times more sensitive than conventional PCR however, 100 times less sensitive than quantitative PCR (qPCR). LAMP assay results were monitored by color change method using picogreen dye and agarose gel electrophoresis.

Conclusion:

LAMP assay can be a very good alternative for CaPV detection to other molecular techniques requiring sophisticated equipments.

Detection and characterization of atypical capripoxviruses among small ruminants in India

Recent developments in molecular biology shed light on cross-species transmission of SPPV and GTPV. The present study was planned to characterize the capripoxviruses which were circulating in the field condition among sheep and goats using RPO30 gene-based viral lineage (SPPV/GTPV) differentiating PCR and sequencing of RPO30 and GPCR genes from clinical samples. Out of 58 scabs (35 sheep and 23 goats) screened, 27 sheep and 18 goat scabs were found positive for capripox virus infections. With the exception of one sheep and one goat scabs, all the positive samples yielded amplicon size according to host origin, i.e. SPPV in sheep and GTPV in goats. In the above two exceptional cases, goat scab and sheep scab yielded amplicon size as that of SPPV and GTPV, respectively. Further, sequencing and phylogenetic analyses of complete ORFs of RPO30 and GPCR genes from six sheep and three goat scabs revealed that with the exception of above two samples, all had host-specific signatures and clustered according to their host origin. In case of cross-species infecting samples, sheep scab possessed GTPV-like signatures and goat scab possessed SPPV-like signatures. Our study identifies the circulation of cross-infecting SPPV and GTPV in the field and warrants the development of single-strain vaccine which can protect the animals from both sheeppox and goatpox diseases.

G-Protein-Coupled Chemokine Receptor Gene in Lumpy Skin Disease Virus Isolates from Cattle and Water Buffalo (Bubalus bubalis) in Egypt

Lumpy skin disease virus (LSDV), sheep poxvirus (SPV) and goat poxvirus (GPV) are the most serious poxviruses of ruminants. In this study, we analysed the G-protein-coupled chemokine receptor (GPCR) genes of LSDV isolates from cattle and water buffalo (Bubalus bubalis) in Egypt during the summer of 2011. Multiple alignments of the nucleotide sequences revealed that the water buffalo LSDV isolate differed from the cattle isolate at four nucleotide positions, and both isolates had nine nucleotide mutations from the reference strain, Egyptian tissue culture-adapted cattle LSDV/Ismailyia88 strain. Compared with the GPCR sequences of SPV and GPV strains, a 21 nucleotide insertion and a 12 nucleotide deletion were identified in the GPCR genes of our used isolates and other LSDVs. The amino acid sequences of GPCR genes of our isolates contained the unique signature of LSDV (A₁₁ , T₁₂ , T₃₄ , S₉₉ and P₁₉₉ ). Phylogenetic analyses showed that the GPCR genes of cattle and water buffalo LSDVs were closest genetically, indicating a potential transmission of cattle LSDV to water buffalo.

Genetic diversity of fusion gene (ORF 117), an analogue of vaccinia virus A27L gene of capripox virus isolates

The fusion gene (ORF 117) sequences of twelve (n = 12) capripox virus isolates namely sheeppox (SPPV) and goatpox (GTPV) viruses from India were demonstrated for their genetic and phylogenetic relationship among them. All the isolates were confirmed for their identity by routine PCR before targeting ORF 117 gene for sequence analysis. The designed primers specifically amplified ORF 117 gene as 447 bp fragment from total genomic DNA extracted from all the isolates. Sequence analysis revealed a significant percentage of identity among GTPV, SPPV and between them at both nucleotide and amino acid levels. The topology of the phylogenetic tree revealed that three distinct clusters corresponding to SPPV, GTPV and lumpy skin disease virus was formed. However, SPPV Pune/08 and SPPV Roumanian Fanar isolates were clustered into GTPV group as these two isolates showed a 100 and 99.3 % identity with GTPV isolates of India at nt and aa levels, respectively. Protein secondary structure and 3D view was predicted and found that it has high antigenic index and surface probability with low hydrophobicity, and it can be targeted for expression and its evaluation to explore its diagnostic potential in epidemiological investigation in future.

Development of an assay to differentiate between virulent and vaccine strains of lumpy skin disease virus (LSDV)

Lumpy skin disease (LSD) was and still is a constant threat to the State of Israel, since the first outbreaks in 1989 and in 2006-2007. Recently, another massive outbreak occurred, at the beginning of July 2012, in the northern part of Israel. An intensive vaccination campaign with a sheeppox-based vaccine was initiated, in addition to culling symptomatic animals in the dairy herds. In spite of this, there was a need to apply extra efforts to completely contain and control the spread of the disease by introducing for the first time in Israel a vaccine based on the Neethling vaccine virus strain. However, in case of appearance of LSD symptoms it was essential to be able to distinguish between cattle-carried virulent strain and the vaccine strain. This paper describes the development and utilization of a molecular assay that can differentiate between the virulent isolates from the vaccine strain. The system is based on 3 different tests; it was found that the vaccine strain carries 27 bases less than the virulent virus in the extracellular enveloped virions (EEV) gene. A temperature-gradient PCRs were done using primers which are identical to the vaccine strain but differ at the 3' end nucleotides to the virulent virus. PCR-RFLP was carried out on the presence of an MboI site unique to the vaccine strain. Thus, all three tests presented here are able to differentiate specifically between the two viral appearances.

Development of loop-mediated isothermal amplification assay for specific and rapid detection of differential goat pox virus and sheep pox virus

Background

Capripox viruses are economically important pathogens in goat and sheep producing areas of the world, with specific focus on goat pox virus (GTPV), sheep pox virus (SPPV) and the Lumpy Skin Disease virus (LSDV). Clinically, sheep pox and goat pox have the same symptoms and cannot be distinguished serologically. This presents a real need for a rapid, inexpensive, and easy to operate and maintain genotyping tool to facilitate accurate disease diagnosis and surveillance for better management of Capripox outbreaks.

Results

A LAMP method was developed for the specific differential detection of GTPV and SPPV using three sets of LAMP primers designed on the basis of ITR sequences. Reactions were performed at 62°C for either 45 or 60 min, and specificity confirmed by successful differential detection of several GTPV and SPPV isolates. No cross reactivity with Orf virus, foot-and-mouth disease virus (FMDV), A. marginale Lushi isolate, Mycoplasma mycoides subsp. capri, Chlamydophila psittaci, Theileria ovis, T. luwenshuni, T. uilenbergi or Babesia sp was noted. RFLP-PCR analysis of 135 preserved epidemic materials revealed 48 samples infected with goat pox and 87 infected with sheep pox, with LAMP test results showing a positive detection for all samples. When utilizing GTPV and SPPV genomic DNA, the universal LAMP primers (GSPV) and GTPV LAMP primers displayed a 100% detection rate; while the SPPV LAMP detection rate was 98.8%, consistent with the laboratory tested results.

Conclusions

In summary, the three sets of LAMP primers when combined provide an analytically robust method able to fully distinguish between GTPV and SPPV. The presented LAMP method provides a specific, sensitive and rapid diagnostic tool for the distinction of GTPV and SPPV infections, with the potential to be standardized as a detection method for Capripox viruses in endemic areas.

Multiplex PCR for simultaneous detection and differentiation of sheeppox, goatpox and orf viruses from clinical samples of sheep and goats

A multiplex polymerase chain reaction (mPCR) was developed and evaluated for detection of pox viral infections simultaneously using clinical samples from sheep and goats. Specific primers for three pox viruses of sheep and goats including sheeppox virus (SPPV), goatpox virus (GTPV) and orf virus (ORFV) were designed targeting conserved sequences of the DNA binding phosphoprotein (I3L) coding gene of Capripoxvirus (CaPV) and the DNA polymerase (E9L) gene of parapoxvirus for identification of these viruses. The mPCR assay was found to be sensitive for detecting as low as 350 pg of viral genomic DNA or 10(2) copies of standard plasmid of individual targets; and 10(3) copies of plasmid in a mixture of two or three viruses. The assay was specific for detecting one or more of the viruses in various combinations from clinical specimens. Two hundred and thirty five (n=235) clinical samples from sheep and goats received from different geographical regions of the country for diagnosis of pox infection were evaluated by developed uniplex and mPCR assays. The assay had improved diagnostic sensitivity and specificity over to in-use laboratory diagnostic methods and can be useful for clinical differential diagnosis of these infections in sheep and goats.

Development of a cost-effective method for capripoxvirus genotyping using snapback primer and dsDNA intercalating dye

Sheep pox virus (SPPV), goat pox virus (GTPV) and lumpy skin disease virus (LSDV) are very closely related viruses of the Capripoxvirus (CaPV) genus of the Poxviridae family. They are responsible for sheep pox, goat pox and lumpy skin disease which affect sheep, goat and cattle, respectively. The epidemiology of capripox diseases is complex, as some CaPVs are not strictly host-specific. Additionally, the three forms of the disease co-exist in many sub-Saharan countries which complicates the identification of the virus responsible for an outbreak. Genotyping of CaPVs using a low-cost, rapid, highly specific, and easy to perform method allows a swift and accurate identification of the causative agent and significantly assists in selecting appropriate control and eradication measures, such as the most suitable vaccine against the virus during the outbreaks. The objective of this paper is to describe the design and analytical performances of a new molecular assay for CaPV genotyping using unlabelled snapback primers in the presence of dsDNA intercalating EvaGreen dye. This assay was able to simultaneously detect and genotype CaPVs in 63 samples with a sensitivity and specificity of 100%. The genotyping was achieved by observing the melting temperature of snapback stems of the hairpins and those of the full-length amplicons, respectively. Fourteen CaPVs were genotyped as SPPVs, 25 as GTPVs and 24 as LSDVs. The method is highly pathogen specific and cross platform compatible. It is also cost effective as it does not use fluorescently labelled probes, nor require high-resolution melting curve analysis software. Thus it can be easily performed in diagnostic and research laboratories with limited resources. This genotyping method will contribute significantly to the early detection and genotyping of CaPV infection and to epidemiological studies.

Development and validation of three Capripoxvirus real-time PCRs for parallel testing

Capripoxviruses have the potential to cause outbreaks with a severe socio-economic impact. The latter, combined with an altered virus dissemination pattern, warrants its status as an important emerging disease. Disease control or eradication programmes can only be applied successfully if the necessary diagnostic tools are available allowing clear and unequivocal identification of the pathogen. Real-time PCR combines high sensitivity/specificity with a reduced analysis time and is thus a proven useful tool for identification of many pathogens, including Capripoxviruses. In order for a real-time PCR to be used in a diagnostic capacity, the different analytical and diagnostic parameters need to be evaluated to assure data quality. The implementation of parallel testing using multiple real-time PCRs with similar characteristics can improve further Capripoxvirus diagnosis. It was therefore the purpose of this study to develop a triplet real-time PCR panel with similar high sensitivity/specificity and provide sufficient validation data regarding the performance characteristics that the panel can be used in parallel, depending on the purpose and local situation.

Animal poxvirus vaccines: a comprehensive review

The family Poxviridae includes several viruses of medical and veterinary importance. Global concerted efforts combined with an intensive mass-vaccination campaign with highly efficaceious live vaccine of vaccinia virus have led to eradication of smallpox. However, orthopoxviruses affecting domestic animals continue to cause outbreaks in several endemic countries. Different kinds of vaccines starting from conventional inactivated/attenuated to recombinant protein-based vaccines have been used for control of poxvirus infections. Live virus homologous vaccines are currently in use for diseases including capripox, parapox, camelpox and fowlpox, and these vaccines are highly effective in eliciting (with the exception of parapoxviruses) long-lasting immunity. Attenuated strains of poxviruses have been exploited as vectored vaccines to deliver heterologous immunogens, many of them being licensed for use in animals. Worthy of note are vaccinia virus, fowlpox virus, capripoxvirus, parapoxvirus and canary pox, which have been successfully used for developing new-generation vaccines targeting many important pathogens. Remarkable features of these vaccines are thermostability and their ability to engender both cellular and humoral immune responses to the target pathogens. This article updates the important vaccines available for poxviruses of livestock and identifies some of the research gaps in the present context of poxvirus research.

Differentiation of sheeppox and goatpox viruses by polymerase Chain reaction-restriction fragment length polymorphism

In the present study, the partial gene sequences of P32 protein, an immunogenic envelope protein of Capripoxviruses (CaPV), were analyzed to assess the genetic relationship among sheeppox and goatpox virus isolates, and restriction enzyme specific PCR-RFLP was developed to differentiate CaPV strains. A total of six goatpox virus (GTPV) and nine sheeppox virus (SPPV) isolates of Indian origin were included in the sequence analysis of the attachment gene. The sequence analysis revealed a high degree of sequence identity among all the Indian SPPV and GTPV isolates at both nucleotide and amino acid levels. Phylogenetic analysis showed three distinct clusters of SPPV, GTPV and Lumpy skin disease virus (LSDV) isolates. Further, multiple sequence alignment revealed a unique change at G120A in all GTPV isolates resulting in the formation of Dra I restriction site in lieu of EcoR I, which is present in SPPV isolates studied. This change was unique and exploited to develop restriction enzyme specific PCR-RFLP for detection and differentiation of SPPV and GTPV strains. The optimized PCR-RFLP was validated using a total of fourteen (n=14) cell culture isolates and twenty two (n=22) known clinical samples of CaPV. The Restriction Enzyme specific PCR-RFLP to differentiate both species will allow a rapid differential diagnosis during CaPV outbreaks particularly in mixed flocks of sheep and goats and could be an adjunct/supportive tool for complete gene or virus genome sequencing methods.

Phylogenetic analysis of Chinese sheeppox and goatpox virus isolates

Background

Sheeppox virus (SPPV) and goatpox virus (GTPV), members of the Capripoxvirus genus of the Poxviridae family are causative agents of sheep pox and goat pox respectively, which are important contagious diseases and endemic in central and northern Africa, the Middle and Far East, and the Indian sub-continent. Both sheep pox and goat pox can cause wool and hide damage, and reduce the production of mutton and milk, which may result in significant economic losses and threaten the stockbreeding. In this study, three SPPVs and two GTPVs were collected from China in 2009 and 2011. We described the sequence features and phylogenetic analysis of the P32 gene, GPCR gene and RPO30 gene of the SPPVs and GTPVs to reveal their genetic relatedness.

Results

Sequence and phylogenetic analysis showed that there was a close relationship among SPPV/GanS/2/2011/China, SPPV/GanS/1/2011/China and SPPV/NingX/2009/China. They were clustered on the same SPPV clade. GTPV/HuB/2009/China and GS-V1 belonged to the GTPV lineage. GS-V1 was closely related to other GTPV vaccine strains. GTPV/HuB/2009/China and GS-V1 were clustered with GTPVs from China and some southern Asian countries.

Conclusion

This study may expand the datum for spread trend research of Chinese SPPVs and GTPVs, meanwhile provide theoretical references to improve the preventive and control strategy.

An outbreak of sheep pox associated with goat poxvirus in Gansu province of China

Three strains of Capripoxviruses (CaPVs) were isolated from an outbreak of sheep pox in Gansu province of China. They were analyzed by P32 gene-based molecular methods and a species-specific PCR based on the RPO30 gene. Two bands which are specific to goat poxvirus (GTPV) were observed after the PCR products of P32 gene were digested with the endonuclease of Hinf I. Moreover, an amplicon of 172 bp, which is specific to GTPV, was amplified from the viruses by using the RPO30 gene-based PCR. Sequence analysis of the P32 genes showed that three nucleotide bases for coding residue of aspartic acid which are located at 163-165 position of P32 gene of sheep poxvirus (SPPV) were absent, and six single nucleotide substitutions which are characteristic of GTPV were present. The viruses were genetically closer to GTPV strains and clustered into the GTPV branch of the phylogenetic tree constructed on the basis of the P32 gene. The results characterized the isolated viruses as GTPV. It is the first report of an outbreak of sheep pox associated with GTPV in China.