Economic and epidemiological aspects of an outbreak of sheeppox in a dairy sheep flock

Structural and sequence analysis of the RPO30 gene of sheeppox and goatpox viruses from India

Sheeppox and goatpox are transboundary viral diseases of sheep and goats that cause significant economic losses to small and marginal farmers worldwide, including India. Members of the genus Capripoxvirus (CaPV), namely Sheeppox virus (SPPV), Goatpox virus (GTPV), and Lumpy skin disease virus (LSDV), are antigenically similar, and species differentiation can only be accomplished using molecular approaches. The present study aimed to understand the molecular epidemiology and host specificity of SPPV and GTPV circulating in India through sequencing and structural analysis of the RNA polymerase subunit-30 kDa (RPO30) gene. A total of 29 field isolates from sheep (n = 19) and goats (n = 10) belonging to different geographical regions of India during the period: Year 2015 to 2023, were analyzed based on the sequence and structure of the full-length RPO30 gene/protein. Phylogenetically, all the CaPV isolates were separated into three major clusters: SPPV, GTPV, and LSDV. Multiple sequence alignment revealed a highly conserved RPO30 gene, with a stretch of 21 nucleotide deletion in all SPPV isolates. Additionally, the RPO30 gene of the Indian SPPV and GTPV isolates possessed several species-specific conserved signature residues/motifs that could act as genotyping markers. Secondary structure analysis of the RPO30 protein showed four α-helices, two loops, and three turns, similar to that of the E4L protein of vaccinia virus (VACV). All the isolates in the present study exhibited host preferences across different states of India. Therefore, in order to protect vulnerable small ruminants from poxviral infections, it is recommended to take into consideration a homologous vaccination strategy.

Spatio-temporal ditribution and transmission dynamics of sheep pox and goat pox diseases in South Wollo zone north East Ethiopia

Sheep pox (SP) and goat pox diseases (GP) are highly transmittable, malignant systemic and economically significant caused by the genus Capripoxvirus. using The spatio-temporal distribution of SP and GP outbreaks in South Wollo zone from September 2013 to December 2019 was determined retrospectively using SP and GP outbreaks report Kombolcha regional laboratory. A follow up study was also conducted from December 2019 to March 2021 to estimate the transmission parameter of SP and GP outbreaks in South Wollo zone of Kutaber district, Amhara region. Tissue samples from outbreaks in Kundi and Haroye kebele of Kutaber district were taken to confirm the outbreak by conventional polymerase chain reaction (PCR). The transmission parameters were estimated using Generalized linear model (GLM) based on stochastic Susceptible Infected and Recovered (SIR) model. In South Wollo zone, 249 SGP outbreaks were reported from 2013 to 2019. The incidence differed between months, with a highest peak in October and November and a lowest peak in February. The basic reproduction ratios (R0) of the SGP disease outbreaks were 1.84 and 3 for Haroye and Kundi kebele outbreaks, respectively. The disease is distributed throughout the zone and the investigated active outbreaks had moderate transmission between animals. Hence, it needs a great effort which focuses on the application of control measures that reduce the transmission of the disease.

Spatiotemporal and seasonality analysis of sheep and goat pox (SGP) disease outbreaks in Turkey between 2010 and 2019

Sheep and goat pox (SGP) is a highly infectious disease with a high case fatality rate. It causes serious economic losses and decreases productivity in infected facilities and contact areas. As in many countries of the world, SGP outbreaks reported from Turkey to the World Organization for Animal Health (OIE) continue to threaten animal health. Therefore, studies that will guide the production of effective policies to prevent and control SGP are extremely important. This study aims at evaluating the spatiotemporal distribution of SGP outbreaks by geographical information system (GIS)-based analyses. In accordance with this purpose, spatiotemporal scan analyses were applied to reveal the spatiotemporal distribution pattern and transmission of SGP outbreaks reported in Turkey between 2010 and 2019. Space-time cluster analysis revealed 4 several clusters, indicating geographic areas at the highest risk. Spatiotemporal clusters were 6 to 11 times more likely to be exposed to SGP than the general distribution. The average spatiotemporal density of outbreaks in clusters was estimated as 0.20 ± 0.07 outbreaks per 1000 km² per month. Seasonal analysis and time series analysis showed similar findings. The seasonality of SGP was mainly defined in the winter (from December to February) when the seasonal adjusted factor (SAF) was at a peak of 504.6. In addition, February had the highest SAF with 7.1. Directional distribution analysis showed that the transmission of SGP was oriented between northeast (NE)-southwest (SW) and northwest (NW)-southeast (SE) and that distribution was changed every 2 years. These findings present a basis for the effective monitoring and prevention of SGP and provide valuable information to policymakers.

Seroprevalence and associated risk factors of pox infection among sheep and goats in selected districts of Afar region, Ethiopia

Background

Sheep and goat pox virus infection is highly devastating viral disease of small ruminants that cause severe production losses in sheep and goats in Ethiopia and also limits international trade. A cross-sectional study was employed with the objective to estimate the seroprevalence of pox infection and to assess associated risk factors during the study period, February to April, 2020. A total of 384 serum samples were collected from apparently healthy sheep and goats. Serum neutralization test was used to detect the presence of antibodies against pox virus at national veterinary institute. Descriptive statistics, univariable and Multivariable logistic analyses were used in this study.

Results

The overall animal level seroprevalence of sheep and goat pox virus was found to be 15.36% (n = 59/384) and species level prevalence rate was found to be 14.5% (n = 16/110) in sheep and 15.69% (n = 43/274) in goats in the study areas. Among the associated factors considered in this study, sex (P = 0.010), age (P = 0.012) and herd size (P = 0.029) were found to be statistically associated with seropositivity of pox infection in multivariable logistic regression. The odds of seropositivity in female animals were 3.9 times more likely to develop pox infection than male animals (AOR = 2.2; 95% CI = 1.203-4.015%) and the odds of young animals were 2.14 times more likely to be seropositive to pox infection than old aged animals (AOR = 2.14; 95% CI = 1.169-3.633%). Moreover, the odds of large-sized flocks of animals were 3.10 times more likely to be seropositive to pox disease than small-sized flocks (AOR = 3.10; 95% CI = 1.30-4.42%).

Conclusion

This study finding revealed that sheep and goat pox virus is prevalent and widespread diseases of small ruminant in afar region. Therefore, further study should be carried out to estimate region wise magnitude of the disease and control measures should be put in place to minimize the economic losses associated with this disease.

[Adaptation of the sheep pox virus (Poxviridae: Capripoxvirus: Sheeppox virus) to African green monkey kidney cell line and evaluation of its immunobiological properties]

INTRODUCTION

Outbreaks of infectious diseases seriously hinder the preservation and increase of the number of small ruminants. Such infections include sheep pox virus (SPPV). According to the OIE data of 2021, SPP outbreaks were registered in countries such as Turkey, Israel, China, Maldives, Mongolia, Thailand, Russia, Algeria, Kenya, and in 2019 in Mangistau and Atyrau regions. In Kazakhstan annually conducts routine immunization of sheep at risk with a live attenuated vaccine produced by RIBSP.

MATERIALS AND METHODS

The object of the study was the vaccine strain of NISHI and the virulent strain A of the sheep pox virus. The virus was propagated in Vero cells. To determine the harmlessness and immunogenicity, sheep of the Kazakh fine-wool breed aged from 6 to 12 months were used. Virological, serological and immunobiological methods were used in the study.

RESULTS

The results of the adaptation of the NISHI strain of SPPV to the Vero cell line are presented. Five passages in Vero cells resulted to the adaptation of the NISHI strain with the manifestation of a cytopathogenic effect specific to SPPV with a titer of 6.50 lg TCD50/ml. Following immunization, the formation of immunity was observed in animals on day 7 with an average protective titer 1.8 log2, which increased by day 21 to 4.33 log2.

CONCLUSION

It has been established that the NISHI strain of SPPV retains its virological and immunobiological properties during reproduction in a Vero cell line.

Transmission dynamics and economic impacts of Sheeppox and Goatpox disease outbreak in Chifra district of Afar Region Ethiopia

Sheep and goatpox are caused by pox virus and economically very important. The study was conducted to estimate the economic losses due to sheep and goatpox, to estimate the morbidity and mortality as well as the transmission parameters. A cross sectional study was conducted in Chifra districts of Afar region from July 2020 to December 2020 using questioner survey. For the estimation of the economic impacts and the transmission parameters of the outbreak, a data was collected at the end of the outbreak through a direct face to face interview. Transmission parameters were estimated based on a final size approach. Whereas, economic impacts were estimated descriptively using different formulas based on the type of losses. The overall morbidity, mortality and case fatality of sheep and goatpox were 51.6%, 2.0%, and 3.9%, respectively. The average flock level losses due to treatment cost, mortality and abortion were 320.3, 1250 and 1195.6 Ethiopian birr (ETB), respectively. The outbreak caused a total of 63617 ETB losses in the district. The highest loss was due to mortality (28750ETB), whereas the least loss was due to treatment cost (7367ETB). The outbreak had 0.14 and 1.41 transmission rate parameters per day and basic reproduction ratio, respectively. There was a significant difference in the transmission of the infection between individual animals (p < 0.001). To limit the economic losses due to this disease, the farmers should give more attention towards this disease and a systematic control program comprising vaccination and limitation of movement of sheep and goat should be implemented to alleviate the losses due to sheep and goatpox.

Seroprevalence of sheeppox and goatpox virus in Asia and African continent: A systematic review and meta-analysis (Scientometrics)

Background and Aim:

Two endemic capripox infectious diseases, sheeppox (SP) and goatpox (GP) are common in Asia, Africa, and the Middle East. Sheep and goats, in general, are considered current assets of small and marginal farmers and have significant economic value in terms of meat, wool, and skin/hide production. Sheep and goat populations in India total 148.88 million and 74.26 million, respectively. Capripox caused US$ 2.3 million (Indian Rupee [INR] 105 million) in economic damages in Maharashtra (India) alone, and it took over 6 years for a flock to recover from the outbreak. The projected yearly loss at the national level is US$ 27.47 million (INR 1250 million). As a result, Capripox diseases put small and marginal farmers under much financial strain. The present study estimates the seroprevalence of SP and GP diseases in the Asian and African continents using systematic review and meta-analysis. The results of the study will help researchers and policymakers to understand the spatial and temporal distribution of the disease and its burden. In addition, the results are also helpful to design and implement location-specific prevention and eradication measures against these diseases.

Materials and Methods:

Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines of Cochran collaborations were used for systematic review and subsequently meta-analysis were used. The literature was collected from various databases. Initial search string resulted in more than nine thousand articles for the period 2000 to 2020 using the different combinations of keywords and Boolean operators (or not) asterisk* and quotation marks. Out of 9398 papers, 80 studies were chosen for complete test reviews and quality bias evaluation using the inclusion and exclusion criteria. Finally, 21 articles were used for the meta-analysis. The statistical study employed fixed effects and random effects models using R.

Results:

Seroprevalence of SP and GP was calculated using studies with a cumulative sample size of 4352, out of which sheep and goats’ samples together contribute 48%, followed by sheep (32%) and goat (21%). The result of the meta-regression revealed that detection techniques had a significant impact on the overall effect size at 5% level (Qm=14.12). Subgroup analysis of polymerase chain reaction (PCR) test with samples was further grouped into two categories based on the median, and it revealed that 62% of samples used PCR as a detecting test followed by group-II.

Conclusion:

From the study, it is concluded that SP and GP diseases are highly prevalent; hence, effective vaccines, proper education to farmers through extension activity, and transboundary disease movement restriction are necessary for the control and eradication of the disease.

Inhibition of bovine and ovine capripoxviruses (Lumpy skin disease virus and Sheeppox virus) by ivermectin occurs at different stages of propagation in vitro

Capripoxvirus diseases are listed as reportable diseases by World Organization for Animal Health (OIE). Lumpy skin disease virus (LSDV) and sheeppox virus (SPPV), which can only be distinguished by molecular analysis, cause moderately, severe, or sometimes fatal infections in cattle and sheep. Even though vaccines are the most effective way to control the infection, their effectiveness may decrease in some cases. Therefore, it is significant to explore antiviral drugs against these diseases along with the vaccine. This study aimed to investigate the antiviral efficiency of ivermectin (IVM) at different stages of in vitro replication of LSDV and SPPV. For this purpose, viral titers (TCID₅₀/mL) of the viruses not treated with IVM (0.0 μM) and treated with non-cytotoxic concentrations of IVM (1.0 and 2.5 μM) were compared during a nine-day (216 h) post-infection period by viral titration assay. At 2.5 μM concentrations of IVM, the mean viral titer was significantly (P<0.05) reduced by approximately three logs for the replication stage of LSDV and SPPV. To evaluate the antiviral activity of IVM against LSDV and SPPV by treatment at the virus attachment and penetration stages, the titers of the virus either untreated or treated with 2,5 μM IVM were compared by virus titration assay. The number of infectious virions for LSDV and SPPV were decreased by 99.82% and 99.87% at the viral replication stage, 68.38% and 25.01% at the attachment stage, and 57.83% and 0.0% at the penetration stage, respectively. It was determined that ivermectin is statistically more effective on LSDV than SPPV at the virus attachment and penetration stages (P<0.05). This study found that the drug IVM can inhibit capripoxviruses, including LSDV and SPPV at various stages of the propagation. Moreover, this research predicted the in vitro antiviral ability of IVM against capripoxvirus infections for the first time.

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.

Assessment of the Impact of Sheep and Goat Pox Lesions on Skin Quality in Selected Ware Houses of Central Ethiopia

Background

The study was performed from January 2016 to May 2017 with the aim of identifying the impact of sheep and goat pox in skin quality in selected localities of central Ethiopia.

Materials and Methods

A total of 1360 fresh, salted and dried skins were examined and graded. Pox lesion positive skins were examined by PCR to identify the agent.

Results

The prevalence of sheep and goat in the study areas was 4.022%. From a total of 86 rejected skins, a large number of skins were in the rejected category (2.78%). There were highly statistically significant associations (p < 0.05) between sheep and goat pox and species and study areas. However, there were no statically significant associations (p > 0.05) between skin size and sheep and pox. Molecular diagnosis of the case revealed that goat pox virus was responsible for the lesion.

Conclusion

Goat pox virus is the main cause of skin rejection and the factor that causes downgrading of skin.

The role of wildlife in the epidemiology and control of Foot-and-mouth-disease And Similar Transboundary (FAST) animal diseases: A review

Transboundary Animal Diseases (TADs) are notifiable diseases which are highly transmissible and have the potential for rapid spread regardless of national borders. Many TADs are shared between domestic animals and wildlife, with the potential to affect both livestock sector and wildlife conservation and eventually, public health in the case of zoonosis. The European Commission for the Control of Foot-and-Mouth Disease (EuFMD), a commission of the Food and Agriculture Organization of the United Nations (FAO), has grouped six TADs as 'Foot-and-mouth disease (FMD) And Similar Transboundary animal diseases' (FAST diseases). FAST diseases are ruminant infections caused by viruses, for which vaccination is a control option. The EuFMD hold-FAST strategy aims primarily at addressing the threat represented by FAST diseases for Europe. Prevention and control of FAST diseases might benefit from assessing the role of wildlife. We reviewed the role of wildlife as indicators, victims, bridge hosts or maintenance hosts for the six TADs included in the EuFMD hold-FAST strategy: FMD, peste des petits ruminants, lumpy skin disease, sheep and goatpox, Rift Valley fever and bovine ephemeral fever. We observed that wildlife can act as indicator species. In addition, they are occasionally victims of disease outbreaks, and they are often relevant for disease management as either bridge or maintenance hosts. Wildlife deserves to become a key component of future integrated surveillance and disease control strategies in an ever-changing world. It is advisable to increase our knowledge on wildlife roles in relevant TADs to improve our preparedness in case of an outbreak in previously disease-free regions, where wildlife may be significant for disease surveillance and control.

Capripoxvirus Infections in Ruminants: A Review

Lumpy skin disease, sheeppox, and goatpox are notifiable diseases of cattle, sheep, and goats, respectively, caused by viruses of the Capripoxvirus genus. They are responsible for both direct and indirect financial losses. These losses arise through animal mortality, morbidity cost of vaccinations, and constraints to animals and animal products' trade. Control and eradication of capripoxviruses depend on early detection of outbreaks, vector control, strict animal movement, and vaccination which remains the most effective means of control. To date, live attenuated vaccines are widely used; however, conferred protection remains controversial. Many vaccines have been associated with adverse reactions and incomplete protection in sheep, goats, and cattle. Many combination- and recombinant-based vaccines have also been developed. Here, we review capripoxvirus infections and the immunity conferred against capripoxviruses by their respective vaccines for each ruminant species. We also review their related cross protection to heterologous infections.

Experimental infection of indigenous North African goats with goatpox virus

Background

Goatpox is a viral disease caused by infection with goatpox virus (GTPV) of the genus Capripoxvirus, Poxviridae family. Capripoxviruses cause serious disease to livestock and contribute to huge economic losses. Goatpox and sheeppox are endemic to Africa, particularly north of the Equator, the Middle East and many parts of Asia. GTPV and sheeppox virus are considered host-specific; however, both strains can cause clinical disease in either goats or sheep with more severe disease in the homologous species and mild or sub-clinical infection in the other. Goatpox has never been reported in Morocco, Algeria or Tunisia despite the huge population of goats living in proximity with sheep in those countries. To evaluate the susceptibility and pathogenicity of indigenous North African goats to GTPV infection, we experimentally inoculated eight locally bred goats with a virulent Vietnamese isolate of GTPV. Two uninfected goats were kept as controls. Clinical examination was carried out daily and blood was sampled for virology and for investigating the antibody response. After necropsy, tissues were collected and assessed for viral DNA using real-time PCR.

Results

Following the experimental infection, all inoculated goats displayed clinical signs characteristic of goatpox including varying degrees of hyperthermia, loss of appetite, inactivity and cutaneous lesions. The infection severely affected three of the infected animals while moderate to mild disease was noticed in the remaining goats. A high antibody response was developed. High viral DNA loads were detected in skin crusts and nodules, and subcutaneous tissue at the injection site with cycle threshold (Ct) values ranging from 14.6 to 22.9, while lower viral loads were found in liver and lung (Ct = 35.7 and 35.1). The results confirmed subcutaneous tropism of the virus.

Conclusion

Clinical signs of goatpox were reproduced in indigenous North African goats and confirmed a high susceptibility of the North African goat breed to GTPV infection. A clinical scoring system is proposed that can be applied in GTPV vaccine efficacy studies.

Spatiotemporal Distributions of Sheep and Goat Pox Disease Outbreaks in the Period 2013-2019 in Eastern Amhara Region, Ethiopia

Sheep and goat pox is highly contagious viral infection of sheep and goats caused by the genus Capripox virus. Clinically, the disease is characterized by fever, macules developing into papules, and necrotic lesions in the skin and nodular lesions in internal organs. In Ethiopia, there are seroprevalence epidemiological studies on the disease. However, the spatiotemporal clustering of sheep and goat pox incidence has not been investigated. A retrospective study design using the outbreak reported data from Kombolcha Regional Laboratory for the years from September 2013 to December 2019 was performed to determine the temporal and spatial distribution of sheep and goat pox outbreaks. A total of 663 sheep and goat pox disease outbreaks were reported in all major parts of Eastern Amhara region between 2013 and 2019. In this period, sheep and goat pox was reported in all administrative zones of Eastern Amhara region (n = 5). The average incidence of sheep and goat pox outbreaks at the district level was 8.61 per 7 years. The incidence differed between areas, being the lowest in hot dry month and highest in warm and cold moist months. Sheep and goat pox outbreaks generally have a peak in November followed by August and a low in May. There is a significant difference in the occurrence of sheep and goat pox disease outbreaks between months and years (p < 0.001). The forecast for the period 2020-2026 revealed that a high number of sheep and goat pox disease outbreaks will occur than the previous one. Therefore, all stakeholders should work cooperatively to combat this disease occurrence, and there should be capacity development for participatory disease search, risk analysis, laboratory diagnosis, and information management in order to respond properly to outbreak of sheep and goat pox disease; thereby, it enhances the prevention and control the disease.

Establishment of a Challenge Model for Sheeppox Virus Infection

Sheeppox virus (SPPV) together with goatpox virus and lumpy skin disease virus form the genus Capripoxvirus of the Poxviridae family. Due to their great economic importance and major impact on livelihood of small-scale farmers, OIE guidelines classify capripox viruses as notifiable diseases. In the present study, we examined pathogenesis of an Indian SPPV isolate and an Egyptian SPPV isolate in sheep. Three different infection routes were tested: (i) intravenous infection, (ii) intranasal infection and (iii) contact transmission between infected and naïve sheep. Clinical course, viremia and viral shedding as well as seroconversion were analyzed in order to establish a challenge model for SPPV infections that can be used in future vaccine studies. Next to in vivo characterization, both SPPV strains underwent next- and third-generation sequencing to obtain high quality full-length genomes for genetic characterization and comparison to already published SPPV sequences.

Experimental evaluation of the cross-protection between Sheeppox and bovine Lumpy skin vaccines

The Capripoxvirus genus includes three agents: Sheeppox virus, Goatpox virus and Lumpy skin disease virus. Related diseases are of economic importance and present a major constraint to animals and animal products trade in addition to mortality and morbidity. Attenuated vaccines against these diseases are available, but afforded cross-protection is controversial in each specie. In this study, groups of sheep, goats and cattle were vaccinated with Romania SPPV vaccine and challenged with corresponding virulent strains. Sheep and cattle were also vaccinated with Neethling LSDV vaccine and challenged with both virulent SPPV and LSDV strains. Animals were monitored by clinical observation, rectal temperature as well as serological response. The study showed that sheep and goats vaccinated with Romania SPPV vaccine were fully protected against challenge with virulent SPPV and GTPV strains, respectively. However, small ruminants vaccinated with LSDV Neethling vaccine showed only partial protection against challenge with virulent SPPV strain. Cattle showed also only partial protection when vaccinated with Romania SPPV and were fully protected with Neethling LSDV vaccine. This study showed that SPPV and GTPV vaccines are closely related with cross-protection, while LSDV protects only cattle against the corresponding disease, which suggests that vaccination against LSDV should be carried out with homologous strain.

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.

Molecular characterization of sheeppox virus from outbreaks in Karnataka, India

AIM

This study aimed to characterize sheeppox virus (SPPV) using the P32 gene of the Capripoxvirus (CaPVs).

MATERIALS AND METHODS

Clinical samples of skin, scabs, and nasal swab from suspected outbreaks Horalagallu (n=13) and Gerahalli (n=11) at Ramanagara district in Karnataka were collected. All the samples were initially subjected to genus-specific diagnostic polymerase chain reaction (PCR). The pooled clinical samples from each outbreak were also subjected to virus isolation. The isolates were confirmed by CaPVs genotyping PCR targeting the full-length P32 gene, followed by sequencing and phylogenetic analysis.

RESULTS

The clinical signs and lesions varied from mild to severe degree with no specificity between age and sex. Specific cytopathic changes in cell morphology were observed in infected Vero cells from both outbreaks, which were confirmed by PCR. The complete P32 gene from two outbreaks was successfully amplified with the expected amplicon size of 1006bp. The sequencing and phylogenetic analysis revealed that both the outbreaks were due to SPPV and shared high similarity with published SPPVs from Karnataka and other parts of India.

CONCLUSION

The current study showed that complete P32 gene-based genotypic PCR assay can be used for genetic characterization and molecular epidemiology of both sheeppox and goatpox diseases and also to differentiate the causative agents. The sequence analysis revealed 100% similarity among the two outbreak isolates suggesting the same strain of the virus and common source of infection for the outbreaks.

Epidemiological Characteristics and Economic Impact of Lumpy Skin Disease, Sheeppox and Goatpox Among Subsistence Farmers in Northeast Nigeria

Lumpy skin disease (LSD), sheeppox (SP), and goatpox (GP) are contagious viral infections, affecting cattle (LSD), sheep and goats (SP and GP) with highly characteristic clinical signs affecting multiple body systems. All three diseases are widely reported to reduce meat, milk, wool and cashmere production although few studies have formally evaluated their economic impact on affected farms. This study aimed to estimate the economic impact and epidemiological parameters of LSD, SP, and GP among backyard and transhumance farmers in northeast Nigeria. A retrospective study was conducted on herds and flocks affected between August 2017 and January 2018 in Bauchi, Nigeria. Herds and flocks were diagnosed based on clinical signs and information was collected once the outbreak concluded using a standardized questionnaire. Data were collected from 99 farmers (87 backyard and 12 transhumance). The median incidence risk and fatality rate were 33 and 0% in cattle, 53 and 34 % in sheep; 50 and 33% in goats, respectively, with young stock having higher incidence risk and fatality rates than adults. Almost all farmers (94%) treated affected animals with antibiotics, spending a median of US$1.96 (min US$0.19–max US$27.5) per herd per day. Slaughtering or selling affected animals at low prices were common coping strategies. Farmers sold live cattle for 47% less than would have been sold if the animal was healthy, while sheep and goats were sold for 58 and 57% less, respectively. Milk production dropped 65% when cows were clinically affected and 35% after they recovered. Cattle lost a median of 10% of their live weight and sheep and goats lost 15%. Overall economic losses at farm level range from US$9.6 to US$6,340 depending on species affected and production system. Most of the farmers (72%) had not replaced all affected animals at the time of the study. Livestock markets were the most common place to sell affected animals and buy replacements, suggesting these are likely hubs for spreading infections. This study confirms the immediate and long-lasting impact of these diseases on subsistence farmers' livelihoods in North-East Nigeria and suggests potential mechanisms for targeted control.

Extended sequencing of vaccine and wild-type capripoxvirus isolates provides insights into genes modulating virulence and host range

The genus Capripoxvirus in the subfamily Chordopoxvirinae, family Poxviridae, comprises sheeppox virus (SPPV), goatpox virus (GTPV) and lumpy skin disease virus (LSDV), which cause the eponymous diseases across parts of Africa, the Middle East and Asia. These diseases cause significant economic losses and can have a devastating impact on the livelihoods and food security of small farm holders. So far, only live classically attenuated SPPV, GTPV and LSDV vaccines are commercially available and the history, safety and efficacy of many have not been well established. Here, we report 13 new capripoxvirus genome sequences, including the hairpin telomeres, from both pathogenic field isolates and vaccine strains. We have also updated the genome annotations to incorporate recent advances in our understanding of poxvirus biology. These new genomes and genes grouped phenetically with other previously sequenced capripoxvirus strains, and these new alignments collectively identified several recurring alterations in genes thought to modulate virulence and host range. In particular, some of the many large capripoxvirus ankyrin and kelch-like proteins are commonly mutated in vaccine strains, while the variola virus B22R-like gene homolog has also been disrupted in many vaccine isolates. Among these vaccine isolates, frameshift mutations are especially common and clearly present a risk of reversion to wild type in vaccines bearing these mutations. A consistent pattern of gene inactivation from LSDV to GTPV and then SPPV is also observed, much like the pattern of gene loss in orthopoxviruses, but, rather surprisingly, the overall genome size of ~150 kbp remains relatively constant. These data provide new insights into the evolution of capripoxviruses and the determinants of pathogenicity and host range. They will find application in the development of new vaccines with better safety, efficacy and trade profiles.

Molecular characterization of Capripox viruses obtained from field outbreaks in Nigeria between 2000 and 2016

Capripox virus infections are endemic diseases of livestock in Nigeria, but there are limited data on molecular characterization of circulating viruses. In this study, we investigated field outbreaks of Capripox virus infections in Nigeria via partial sequencing of viruses obtained from field samples. Eleven selected samples, collected from 2000-2016 from cattle (9), sheep (1) and goat (1) in three states in Nigeria and Capripox virus genome positive by PCR and real-time qPCR, were characterized using our newly developed partial sequencing protocol. This method for genetic characterization of Capripox virus strains allows a first, short molecular classification of strains responsible for the investigated field outbreaks in the country. Phylogenetically, the eight LSDV samples obtained from 2010 to 2016 are closely related to already published strains occurring in Greece and Serbia in the years 2015 and 2016, respectively, whereas the isolate from 2000 shows high similarity to the South African NI-2490 strain. These data indicate that there was a change of LSDV strains circulating in Nigeria between the years 2000 and 2010. The samples isolated from a goat and a sheep in different years seem to be related to already known GTPV strains, but clearly differ from all current published GTPV strains. Interestingly, both newly detected GTPV strains show up to 100% similarity compared to each other and led to clinical disease in sheep and goats. It is long known that some strains of GTPV and SPPV are able to infect both sheep and goats, but in most cases lead to more severe disease in only one of these species. Further genetic characterization of these isolates could provide more insight into pathogenesis and virulence factors of Capripox viruses, especially GTPV and SPPV.

Species-specific inhibition of capripoxvirus replication by host antiviral protein kinase R

The role of interferon (IFN)‐induced protein kinase R (PKR) in capripoxvirus (CaPV)‐infected cells remains unknown. In this study, we show that CaPV infection triggered PKR and eukaryotic translation initiation factor 2 alpha (eIF2α) protein phosphorylation in a dose‐dependent manner, and that this leads to decreased CaPV replication. Overexpression of PKR compromised viral gene expression and inhibited sheeppox virus (SPPV) replication. Downregulation of PKR with siRNAs significantly decreased eIF2α phosphorylation and reduced the mRNA level of IFN‐β, which increased virus replication. In luciferase assays, species‐different CaPVs K3L proteins inhibited sheep PKR (sPKR): goatpox virus K3L strongly inhibited sPKR and goat PKR (gPKR), but SPPV K3L only partially inhibited gPKR. These results are the first to show that SPPV infection induces phosphorylation of eIF2α through PKR activation, which then results in restriction of CaPV replication. Furthermore, our data show that CaPV K3L inhibits PKR in a species‐specific manner. The results presented are consistent with the hypothesis that different levels of PKR inhibition by K3L orthologs from various viruses could potentially contribute to the host range function of K3L.

Sero-prevalence, risk factors and distribution of sheep and goat pox in Amhara Region, Ethiopia

Background

Sheep pox and goat pox are contagious viral diseases of sheep and goats, respectively. The diseases result in substantial economic losses due to decreased milk and meat production, damage to hides and wool, and possible trade restriction. A study was undertaken in Amhara region of Ethiopia. A cross-sectional study design was used to estimate the sero-prevalence and identify associated risk factors, while retrospective study design was used to assess the temporal and spatial distribution of the disease. A total of 672 serum samples were collected from 30 Kebeles and tested using virus neutralization test.

Results

From a total of 672 sera tested, 104 (15.5%) were positive for sheep and goat pox virus antibody; from which 56 (17%) were sheep and 48 (14%) were goats. The diseases were prevalent in all study zones, the highest sero-prevalence was observed in South Gondar (20.9%) and the lowest in North Gondar and West Gojjam zones (11.9% each). From the potential risk factors considered (species, sex, age, agro-ecology and location); only sex and age were significantly associated (p < 0.05) with the diseases in multivariable logistic regression. Female and young animals were at higher risk than their counterparts. From January 2010 to December 2014, a total of 366 outbreaks, 12,822 cases and 1480 deaths due to SP and 182 outbreaks, 10,066 cases and 997 deaths due to GP were recorded in Amhara National Regional State.

Conclusion

Both the serological and the outbreak data revealed that sheep and goat pox is one of the most prevalent and widespread diseases of sheep and goats in the study area. Hence, annual mass vaccination program must be implemented for economic and viable control of sheep and goat pox diseases in the Amhara region in particular and at a national level in general.

Electronic supplementary material

The online version of this article (10.1186/s12917-017-1312-0) contains supplementary material, which is available to authorized users.

Development of duplex PCR for differential detection of goatpox and sheeppox viruses

Background

Clinically, sheeppox and goatpox have the same symptoms and cannot be distinguished serologically. A cheaper and easy method for differential diagnosis is important in control of this disease in endemic region.

Methods

A duplex PCR assay was developed for the specific differential detection of Goatpox virus (GTPV) and Sheeppox virus (SPPV), using two sets of primers based on viral E10R gene and RPO132 gene.

Results

Nucleic acid electrophoresis results showed that SPPV-positive samples appear two bands, and GTPV-positive samples only one stripe. There were no cross-reactions with nucleic acids extracted from other pathogens including foot-and-mouth disease virus, Orf virus. The duplex PCR assay developed can specially detect SPPV or GTPV present in samples (n = 135) collected from suspected cases of Capripox.

Conclusions

The duplex PCR assay developed is a specific and sensitive method for the differential diagnosis of GTPV and SPPV infection, with the potential to be standardized as a detection method for Capripox in endemic areas.

Investigation of a Possible Link Between Vaccination and the 2010 Sheep Pox Epizootic in Morocco

Sheep pox is endemic in most parts of Northern Africa and has the potential to cause severe economic problems. Live attenuated vaccines are used in Morocco, and in many other countries, to control the disease. Sheep pox virus (SPPV) re-appeared in 2010 causing a nodular clinical form previously not observed in Morocco. The severe clinical signs observed during the course of this outbreak and initial reports citing similarity in nucleotide sequence between the Moroccan vaccine strain and field isolates warranted a more in depth analysis of this epizootic. In this study, sequence analysis showed that isolates obtained from four provinces of eastern Morocco were identical, demonstrating that a single SPPV strain was responsible for the 2010 epizootic. In addition, the genome fragments sequenced and phylogenetic analyses undertaken as part of this study showed significant differences between field isolates and the Moroccan vaccine strain. New PCR methods were developed to differentiate between wild-type isolates and vaccine strains of SPPV. Using these methods, no trace of wild-type SPPV was found in the vaccine and no evidence was found to suggest that the vaccine strain was causing clinical disease.

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.

Yemen and Vietnam capripoxviruses demonstrate a distinct host preference for goats compared with sheep

Sheeppox and goatpox are caused by viruses that are members of the genus Capripoxvirus, and globally result in significant production losses. To improve the understanding of disease pathogenesis and evaluate host species preferences, sheep and goats were inoculated either with a capripoxvirus isolate from Yemen or from a recent outbreak in Vietnam. Blood, swabs and tissues were collected at various time points following experimental challenge and assessed for viral DNA content using real-time PCR and infectivity using virus isolation. The Yemen isolate was considerably more pathogenic in goats with 100 % mortality and morbidity compared with sheep with 0 % mortality and 100 % morbidity. The Vietnam isolate was also more pathogenic in goats with 100 % morbidity and an estimated 33 % mortality rate compared with mild morbidity and a 0 % mortality rate in sheep. Higher viral titres were observed in nasal, oral and conjunctival swabs from goats inoculated with either the Yemen or Vietnam isolate compared with those collected from sheep. Although the highest viral titres were detected in primary and secondary skin lesions in sheep and goats, the severity of clinical disease observed in each species varied according to the inoculum used. Whereas both the Yemen and Vietnam isolates clearly caused more severe disease in goats, the Yemen isolate was also moderately pathogenic in sheep. The Vietnam isolate, in contrast, caused only very mild disease in sheep. Limited DNA sequencing revealed ORF 074 of the Vietnam isolate to be identical to that of several goatpox virus isolates from China, suggesting a possible Chinese origin.

Capripoxviruses: an emerging worldwide threat to sheep, goats and cattle

Capripoxviruses are the cause of sheeppox, goatpox and lumpy skin disease (LSD) of cattle. These diseases are of great economic significance to farmers in regions in which they are endemic and are a major constraint to international trade in livestock and their products. Although the distribution of capripoxviruses is considerably reduced from what it was even 50 years ago, they are now expanding their territory, with recent outbreaks of sheeppox or goatpox in Vietnam, Mongolia and Greece, and outbreaks of LSD in Ethiopia, Egypt and Israel. Increased legal and illegal trade in live animals provides the potential for further spread, with, for instance, the possibility of LSD becoming firmly established in Asia. This review briefly summarizes what is known about capripoxviruses, including their impact on livestock production, their geographic range, host-specificity, clinical disease, transmission and genomics, and considers current developments in diagnostic tests and vaccines. Capripoxviruses have the potential to become emerging disease threats because of global climate change and changes in patterns of trade in animals and animal products. They also could be used as economic bioterrorism agents.