Sheep Pox Outbreaks Research Articles

Lessons Learned from Active Clinical and Laboratory Surveillance during the Sheep Pox Virus Outbreak in Spain, 2022-2023.

In September 2022, more than 50 years after its eradication from Spain, Sheep pox virus was confirmed by laboratory analysis in sheep showing characteristic lesions. This was the start of an outbreak that lasted 9 months and infected 30 farms dispersed over two different areas, Andalusia and Castilla-La Mancha. Early after the initial confirmation, an active surveillance based on clinical inspection with laboratory confirmation of sheep with clinical signs was started in restricted areas. This allowed the confirmation of Sheep pox in 22 out of 28 suspected farms, where limited numbers of sheep with mainly erythema and papules were found, indicative of early detection. Nevertheless, to improve active surveillance and stop the outbreak, clinical inspection was reinforced by laboratory analysis in all inspected farms, even when no clinically diseased sheep were detected. Although more than 35,000 oral swabs from 335 farms were analysed by real-time PCR in pools of five, only two out of six reported outbreaks in this period were detected by laboratory analysis before clinical signs were observed. Furthermore, additional insights were gained from the extensive laboratory surveillance performed on samples collected under field conditions. No evidence of Sheep pox virus infection was found in goats. Oral swabs proved to be the sample of choice for early detection in the absence of scabs and could be tested in pools of five without extensive loss in sensitivity; serology by ELISA was not useful in outbreak detection. Finally, a non-infectious genome of the virus could be detected months after cleaning and disinfection; thus, real-time PCR results should be interpreted with caution in sentinel animals during repopulation. In conclusion, the outbreak of Sheep pox virus in Spain showed that active clinical inspection with laboratory confirmation of clinically diseased sheep via oral swab testing proved a sensitive method for detection of infected farms, providing insights in laboratory surveillance that will be helpful for other countries confronted with Sheep pox outbreaks.

Molecular and Epidemiological Analyses of Sheeppox Outbreaks in Russia from 2013 to 2021

Sheeppox (SPP) is a transboundary infectious disease that affects sheep and goats, leading to significant losses in countries with extensive small ruminant breeding programs. While sporadic SPP outbreaks have been observed in the Russian Northern Caucasus and the Far East, the number of SPP outbreaks in the Russian Central and Far East regions has increased recently. However, there is a lack of epidemiological data on SPP virus (SPPV) in the Northern latitudes. In this study, we conducted epidemiological and genetic analyses of SPP outbreaks in Russia from 2013 to 2021 using whole-genome sequences of five selected isolates. The epidemiological data revealed an elevated risk of SPP outbreaks during the summer months, although outbreaks were not limited to this period. A phylogenetic analysis of the whole-genome sequences of selected SPPVs obtained directly from clinical samples revealed a unique cluster of SPPV isolates circulating in Central Russia, which was related to previous isolates from the European part of Russia. In contrast, SPPVs obtained from the Russian Far East showed genetic similarity to isolates detected in Southeast Asia. The whole-genome sequences demonstrated that the reported outbreaks were not related to the NISKHI vaccine strain, which was used to combat lumpy skin disease and SPP in Russia. Based on the study findings and GenBank data, we propose a novel cluster designation system for SPPV genomic sequences.

Sero-Prevalence and Risk Factors for Sheep Pox and Its Comparison to Capri pox Double Antigen Multispecies Elisa in Kordofan States in Sudan

A cross-sectional survey was performed in the Kordofan region, from March to September 2011 was compared to Capripox Double Ag ELISA for multispecies. The estimated overall sero-prevalence of sheep pox in Kordofan region was 73.4% determined by virus neutralization and was prevalent in both South and North Kordofan states at 85% and 63.6% respectively. However, Seroprevalence for lumpy skin disease was 5% and 62% for sheep pox by using Capripox Double Ag ELISA. The serological information was used to identify potential risk factors associated with sheep pox outbreaks. The risk factors identified were the breed, age, sex, species, movement patterns, herd size and geographic region. In addition, a questionnaire explored producer’s knowledge about the disease in the Sudan. The results of the questionnaire were that both nomadic as well as fixed farmers were generally aware of sheep pox as a disease, but most did not have full knowledge about the disease. Greater than half of producers experienced the disease in the past 2 years and did not have their sheep vaccinated.

Genetic characterization of sheep pox virus strains from outbreaks in Central Russia in 2018-2019.

This study investigates the phylogenomic relatedness between sheep pox viruses (SPPVs) circulating in Central Russia in 2018-2019 with the NISKHI vaccine strain used in the country, based on their complete genome sequences. The sheep pox outbreaks occurred 1 year apart in the adjacent regions of Tula and Moscow. Full genome sequences were generated by sequencing DNA directly obtained from Trizol-extracted scabs, using the DNBSEQ-400 platform (MGI Tech, China). Phylogenetic analysis indicated that the SPPV isolates from Russia clusters with previously published sequences from Srinagar in the Kashmir province of India in 2000 (SPPV-Srinagar strain) as well as SPPV A strain from Kazakhstan in 2000. The aforementioned cluster belonged to a sister clade containing the NISKHI vaccine strain, thus indicating that the recent outbreaks were not genetically linked to the widely used vaccine.

Investigation of an outbreak of sheeppox among native sheep breeds in the Western Himalayas of India.

An outbreak of sheeppox was investigated in a cluster of villages situated in Western Himalayan ranges of a Northern Indian state. Non-migratory sheep (n = 80) of native breeds namely Gaddi and Rampur Bushair were infected and 15 have died. The outbreak started after a few animals contracted the disease during the summer grazing period at the highland pastures from migrating flocks of sheep. This initial outbreak resulted in a further spreading of the disease into the valley. Clinical examination revealed varying degree of cutaneous papular lesions and respiratory distress. Upon necropsy, visceral lesions in the lungs, trachea and kidneys were also found. Clinical and morbid samples were found positive for sheeppox virus using group specific P32 gene and I3L gene based multiplex PCR differentiating sheeppox and goatpox viruses. Histopathological, hematological and blood biochemical analysis also supported the pathology of an acute viral infection. The causative sheeppox virus strain was isolated using lamb testicular cell culture and phylogenetic analysis, based upon P32 and RPO30 genes, showed its clustering with other Indian strains reported from neighboring states. This study demonstrated the spread of sheeppox virus to new niches by migratory sheep flocks leading to establishment of endemic infections in many new pockets of higher Western Himalayas.

A field study evaluating the humoral immune response in Mongolian sheep vaccinated against sheeppox virus.

Sheeppox is a transboundary disease of small ruminants caused by infection with the capripoxvirus sheeppox virus. Sheeppox is found in Africa, the Middle East and Asia and is characterized by fever, multifocal cutaneous raised lesions and death. Vaccination with live attenuated capripoxvirus (CPPV) strains is an effective and widely used strategy to contol sheeppox outbreaks; however, there are few reports of post-vaccination field surveillance studies. This study used a commercially available enzyme-linked immunosorbent assay (ELISA) to examine quantitative and temporal features of the humoral response of sheep vaccinated with a live-attenuated CPPV strain in Mongolia. Four hundred samples were tested using the ELISA commercial kit, and a subset of 45 samples were also tested with a virus neutralization test (VNT). There was substantial agreement between the VNT and ELISA tests. Antibodies to CPPV were detected between 40 and 262 days post-vaccination. There was no significant difference between serological status (positive/negative) and sex or age; however, an inverse correlation was found between the length of time since vaccination and serological status. Animals between 90 and 180 days post-vaccination were more likely to be positive than animals greater than 180 days post-vaccination. Our results show that a commercial CPPV ELISA kit is a robust and reliable assay for post-CPPV vaccination surveillance in resource-restricted settings and provide temporal parameters to be considered when planning sheeppox post-vaccination monitoring programmes.

Sero Prevalence and Risk factors forSheep Pox and Lumpy Skin Disease and Their Comparison to Capri Pox Double Antigen Multispecies ELISA in Khartoum and Kordofan States in Sudan

A cross-sectional survey was performed in the Kordofan region, from March to September 2011 was compared to Capripox Double Ag ELISA for multispecies. The estimated overall sero-prevalence of sheep pox in Kordofan region was 73.4% determined by virus neutralization and was prevalent in both South and North Kordofan states at 85% and 63.6% respectively. However, Seroprevalence for lumpy skin A cross-sectional survey was performed in the Kordofan region, from March to September 2011 was compared to Capripox Double Ag ELISA for multispecies. The estimated overall sero-Prevalence of sheep pox in Kordofan region was 73.4% determined by virus neutralization and was prevalent in both South and North Kordofan states at 85% and 63.6% respectively. However, Sero-Prevalence for lumpy skin disease was 5% and 62% for sheep pox by using Capripox Double Ag ELISA. The serological information was used to identify potential risk factors associated with sheep pox outbreaks. The risk factors identified were the breed, age, sex, species, movement patterns, herd size and geographic region. In addition, a questionnaire explored producer’s knowledge about the disease in the Sudan. The results of the questionnaire were that both nomadic as well as fixed farmers were generally aware of sheep pox as a disease, but most did not have full knowledge about the disease. Greater than half of producers experienced the disease in the past 2 years and did not have their sheep vaccinated.disease was 5% and 62% for sheep pox by using Capripox Double Ag ELISA. The serological information was used to identify potential risk factors associated with sheep pox outbreaks. The risk factors identified were the breed, age, sex, species, movement patterns, herd size and geographic region. In addition, a questionnaire explored producer’s knowledge about the disease in the Sudan. The results of the questionnaire were that both nomadic as well as fixed farmers were generally aware of sheep pox as a disease, but most did not have full knowledge about the disease. Greater than half of producers experienced the disease in the past 2 years and did not have their sheep vaccinated.

Understanding the epidemiology of sheep-pox outbreaks among vaccinated Algerian sheep and post vaccination evaluation of the antibodies kinetics of the commercially used vaccine

Sheep pox is a disease of veterinary concern to small ruminant producers and veterinary diagnosticians, because of the associated tangible economic losses. The epidemiological analysis of sheep pox, among vaccinated sheep flock in Algeria from 2007 to 2016, showed that the disease outbreaks occurred every year and across all Algeria region with an average of 44.9 outbreaks per year, these outbreaks correlate with the region climate, the flocks’ density and the transhumance practices. The one-year post vaccination antibody kinetics evaluation study of the commercially used vaccine in Algeria demonstrated a mild humoral response, the neutralization index range between 0.73 and 1.22. Therefore, the present study recommends a challenge study, using a virulent local strain, to evaluate the vaccine efficacy. Furthermore, quality control approach for the vaccine production processes is required.

An epizootiological survey of sheep pox in Greece from 1982 to 1998

Sheep pox outbreaks in Greece during the last 17 years are reviewed. It is believed that the disease is mostly introduced from eastern neighboring countries. The transmission of the virus is connected to the movements and contact of sheep flocks. It is also attributed to human-animal contacts. Disease foci appeared in several central and northeastern areas of the country. Between 1982 and 1986 the country remained sheeppox free. The first outbreak appeared in the island of Lesbos in 1987. In 1988 sheeppox outbreaks did occur in the Evros prefecture. In 1994 one new outbreak occurred in Evros. During the 1995-1998 period several outbreaks occurred in Evros and other regions, such as in Thessaloniki (1995), Larissa, Xanthi, Rodopi, Kavala, Magnissia, and Lemnos island (1996), Kavala, Magnissia, Halkidiki, and Samothraki island (1997). In 1998 the cases of sheeppox were reduced and occurred only in prefecture of Evros.

Sheep pox in Tunisia: Current status and perspectives.

Sheep pox, a well-known endemic capripox infection, has significant impacts on small ruminant populations in Tunisia. It is responsible for high economic losses throughout North Africa due to its enzootic nature and to the active animal transhumance existing in some governorates in Tunisia. The aim of this review was to analyse data gathered on annual vaccination campaigns designed to control its spread by reducing the level of endemicity and to describe diagnostic and management tools adapted to the Tunisian situation. Seasonal, temporal and spatial distributions of sheep pox outbreaks, as well as related clinical features, were found. It was concluded from this review that establishing strong herd immunization through individual animal immunization, creating adequate infrastructure, increasing awareness among breeders, setting up a field-based surveillance network and improving routine diagnostic methods need to be the major components of a programme to eradicate the disease. It was also felt that cost-benefit analyses of the surveillance and control strategies used would help in controlling its persistence.

An outbreak of sheep pox in an organized farm of Tamil Nadu, India

Outbreak of sheep pox was noticed in flocks of Khilakaraisal in an organized government farm of Tirunelveli district during 2013. Mortality and morbidity rates were 4.17% and 80.00%, respectively. Both the sexes of sheep between 6 months to 2 years old were affected. DNA extracted from the scab specimens (n=5) were amplified using Capri pox specific p32 gene primers and yielded 192 bp product. In order to differentiate between sheep pox and goat pox PCR – RFLP was carried out. Digestion of PCR product with EcoRI enzyme yielded two fragments with a size of 123 bp and 63 bp which confirmed the presence of sheep pox virus. Histopathological examination of tissues revealed extensive hydropic degeneration of proliferating epidermal cells with presence of large number of intracytoplasmic eosinophilic inclusion bodies in the keratinocytes of epidermal cells in skin. Lung revealed large infiltration of lymphocytes and macrophages with presence of intracytoplasmic eosinophilic inclusions in the macrophages, proliferation of type II pneumocytes were prominent along with bronchiolar epithelial hyperplasia. The outbreak was controlled by effective preventive measures like vaccination of healthy animals, affected animals were treated with a course of antibiotic for 7 days, contaminated areas were disinfected and restricted the movement of animals from unaffected areas to infected areas.

Outbreak of sheeppox in farmed sheep in Kyrgystan: Histological, eletron microscopical and molecular characterization.

On a farm in the Kyrgyz Republic, several dead sheep were found without any history of illness. The sheep showed several ulcerations on lips and bare-skinned areas. At necropsy the lungs showed multiple firm nodules, which were defined as pox nodules histologically. In the rumen hyperkeratotic plaques were visible. With electron microscopy pox viral particles were detected and confirmed with q PCR as Capripoxviruses. Although all members of the Capripoxvirus genus are eradicated in western countries, this study should remind us of the classical lesions observed in poxvirus infections.

An Outbreak of Sheep Pox in Zabajkalskij kray of Russia

In this study, we investigated recent sheep pox outbreaks that occurred in Ononsky and Borzunsky regions of Zabajkalskij kray of Russia. The outbreaks involved in 2756 animals of which 112 were infected and 3 were slaughtered. Samples of injured skin of infected sheep were analysed by electron microscopy and CaPV-specific P32 gene amplification. Following sequence analysis of entire P32 gene showed that both specimens were identical to the sequence of several sheep poxvirus isolates from China and India. The close location of China to the last decade's Russian outbreaks suggest that possible future outbreaks in Russia could occur along the border regions with countries where sheep and goat pox are not controlled.

Identification and phylogenetic analysis of a sheep pox virus isolated from the Ningxia Hui Autonomous Region of China

An outbreak of sheep pox was investigated in the Ningxia Hui Autonomous Region in China. Through immunofluorescence testing, isolated viruses, polymerase chain reaction identification, and electron microscopic examination, the isolated strain was identified as a sheep pox virus. The virus was identified through sequence and phylogenetic analysis of the P32 gene, open reading frame (ORF) 095, and ORF 103 genes. This study is the first to use the ORF 095 and ORF 103 genes as candidate genes for the analysis of sheep pox. The results showed that the ORF 095 and ORF 103 genes could be used for the genotyping of the sheep pox virus.

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 172bp, 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.

Pox outbreaks in Sheep and Goats at Makhdoom (Uttar Pradesh), India: Evidence of Sheeppox Virus Infection in Goats

Sheeppox and goatpox outbreaks occur often in India incurring huge economic loss to the small ruminant industry. This paper describes two sheeppox outbreaks, of which one occurred in an organized sheep breeding farm at Makhdoom (Uttar Pradesh), India, during 2007 and another in goats at the Central Institute of Research on Goats, Makhdoom (Uttar Pradesh), India during 2008. In the first outbreak, a local Muzaffarnagari sheep breed was affected (n=477) with morbidity and mortality rates, respectively, of 100% and 53.9% accompanied by significant productivity losses. In the 2008 outbreaks, a small number of goats were affected without any mortality. The tissue and swabs collected from both the outbreaks were processed and inoculated onto Vero cells, and the causative agent of the outbreaks, capripox virus (CaPV), was isolated. The identity of the virus was confirmed as CaPV based on electron microscopy, experimental pathogenesis in sheep, capripox-specific conventional and real-time PCRs. Sequence analysis of the P32 envelope protein gene revealed that the causative agent of both outbreaks was confirmed as sheeppox virus (SPPV) implying SPPV infection not only in sheep but also goats in India.

A description of two outbreaks of capripoxvirus disease in Mongolia

Mongolia had no reported cases of capripoxvirus disease from 1977 until an outbreak of sheeppox in 2006–2007 and then goatpox in 2008. The two outbreaks occurred in geographically distant areas of Mongolia and, most strikingly, were highly species-specific. The 2006–2007 sheeppox outbreak affected no goats and the 2008 goatpox outbreak affected no sheep despite communal herding. The diseases were diagnosed using the polymerase chain reaction and virus neutralisation test. The P32 gene of the Mongolian sheeppox and goatpox viruses from the recent outbreaks were sequenced and compared with an archived 1967 strain of Goatpox virus from Mongolia. The P32 gene of the 2006–2007 Mongolian Sheeppox virus strain was identical to previously published sheeppox strains. The P32 gene of the 2008 Mongolian Goatpox virus strain was identical to the gene from virus isolated from recent goatpox outbreaks in China and Vietnam. The archived Mongolian Goatpox virus strain was unique.

The epidemiology of sheep pox in Greece from 1987 to 2007

The authors reviewthe epidemiology of sheep pox outbreaks in Greece between 1987 and 2007. It is believed that sheep pox is introduced into Greece principally from neighbouring countries to the east, and is associated with the movements of infected sheep flocks close to the border and contacts between humans and animals. Disease foci have appeared in several central and north-eastern areas of the country. Between 1982 and 1986, Greece remained free of sheep pox but, in 1987, the disease appeared on the island of Lesvos and, in 1988, outbreaks were seen in the prefecture of Evros. In 1994, a further outbreak occurred in Evros. Over the next four years, more outbreaks occurred in Evros and Thessaloniki (1995); Larissa, Xanthi, Rhodopi, Kavala, Magnissia, Evros and the island of Lesvos (1996); Kavala, Magnissia, Halkidiki, Evros and Rhodopi (1997). In 1998, there were fewer cases of sheep pox, with outbreaks only in the prefecture of Evros. Two years later, a further outbreak was reported in Evros (2000), while the most recent outbreak occurred on the island of Lesvos in January 2007.

An outbreak of sheep pox on a sheep breeding farm in Jammu, India

An outbreak of sheep pox occurred in December 2001 on a sheep breeding farm in Jammu, India. The farm maintains three exotic breeds of sheep, i.e. American Merino, Rambouillet and Australian cross. The disease agent was confirmed as sheep pox virus by clinical and post-mortem examination as well as laboratory testing. Typical pock lesions were dispersed over the body of the affected animals with nodular lesions observed in the lung tissue of the dead animals. Sheep pox virus antigen and antibody were detected in infected tissue and convalescent sera, respectively, with serological tests. Viral deoxyribonucleic acid was extracted from the infected tissue and amplified using a diagnostic polymerase chain reaction. Sheep of the Rambouillet breed were found to be most susceptible to infection with morbidity and mortality rates of 26.9% and 8.3%, respectively. Morbidity and mortality rates in the entire flock were 18.4% and 6.3%, respectively. The grazing and migration pattern indicates that the disease was probably introduced to the farm by local sheep.

An outbreak of sheep pox associated with unusual winter conditions in Jordan.

An outbreak of sheep pox associated with unusual winter conditions in Jordan.