Genome sequence characterization of the unique recombinant vaccine-like lumpy skin disease virus strain Kurgan/2018

In 2018, the molecular epidemiology of lumpy skin disease in Russia was characterized by a surge in novel recombinant vaccine-like strains causing outbreaks along the southern border, spreading in an easterly direction. Currently, five distinct novel recombinant vaccine-like lineages have been described, designated as clusters 2.1 to 2.5. Based on the complete genome sequence analysis of the causative lumpy skin disease virus (Kurgan/Russia/2018), obtained from an eponymous outbreak, the genome was shown to be composed of a Neethling vaccine strain virus as the dominant parental strain and KSGPO vaccine virus as its minor parental strain. These features are similar to those of Saratov/Russia/2017 and Tyumen/Russia/2018, representing clusters 2.1 and 2.4, respectively. However, Kurgan/Russia/2018 has 16 statistically significant recombination events unique to this sequence, contributing to the phylogenetic clustering of Kurgan/Russia/2018 in yet another cluster designed cluster 2.6, based on analysis involving the complete genome sequences.

Lumpy skin disease: Insights into current status and geographical expansion of a transboundary viral disease

Lumpy skin disease (LSD) is an emerging transboundary viral disease of livestock animals which was first reported in 1929 in Zambia. Although LSD is a neglected disease of economic importance, it extends a direct impact on the international trade and economy in livestock-dependent countries. Lumpy skin disease virus (LSDV) has been endemic in African countries, where several outbreaks have been reported previously. However, the virus has spread rapidly across the Middle East in the past two decades, reaching Russia and, recently, the Asian subcontinent. With unprecedented cluster outbreaks being reported across Asian countries like India, China, Nepal, Bangladesh, and Pakistan, LSDV is certainly undergoing an epidemiological shift and expanding its geographical footprint worldwide. Due to high mortality among livestock animals, the recent LSD outbreaks have gained attention from global regulatory authorities and raised serious concerns among epidemiologists and veterinary researchers. Despite networked global surveillance of the disease, recurrent LSD cases pose a threat to the livestock industry. Hence, this review provides recent insights into the LSDV biology by augmenting the latest literature associated with its pathogenesis, transmission, current intervention strategies, and economic implications. The review critically examines the changing epidemiological footprint of LSDV globally, especially in relation to developing countries of the Asian subcontinent. We also speculate the possible reasons contributing to the ongoing LSD outbreaks, including illegal animal trade, climate change, genetic recombination events between wild-type and vaccine strains, reversion of vaccine strains to virulent phenotype, and deficiencies in active monitoring during the COVID-19 pandemic.

Evaluation of the safety, immunogenicity and efficacy of a new live-attenuated lumpy skin disease vaccine in India

Lumpy skin disease (LSD) was reported for the first time in India in 2019 and since then, it has become endemic. Since a homologous (LSD-virus based) vaccine was not available in the country, goatpox virus (GPV)-based heterologous vaccine was authorized for mass immunization to induce protection against LSD in cattle. This study describes the evaluation of safety, immunogenicity and efficacy of a new live-attenuated LSD vaccine developed by using an Indian field strain, isolated in 2019 from cattle. The virus was attenuated by continuous passage (P = 50) in Vero cells. The vaccine (50^th LSDV passage in Vero cells, named as Lumpi-ProVac^Ind) did not induce any local or systemic reaction upon its experimental inoculation in calves (n = 10). At day 30 post-vaccination (pv), the vaccinated animals were shown to develop antibody- and cell-mediated immune responses and exhibited complete protection upon virulent LSDV challenge. A minimum Neethling response (0.018% animals; 5 out of 26,940 animals) of the vaccine was observed in the field trials conducted in 26,940 animals. There was no significant reduction in the milk yield in lactating animals (n = 10108), besides there was no abortion or any other reproductive disorder in the pregnant animals (n = 2889). Sero-conversion was observed in 85.18% animals in the field by day 30 pv.

Identifying the patterns and sizes of the first lumpy skin disease outbreak clusters in Northern Thailand with a high degree of dairy farm aggregation using spatio-temporal models

Lumpy skin disease (LSD) is one of the most important notifiable transboundary diseases affecting cattle in many parts of the world. In Thailand, LSD outbreaks in cattle farming areas have been reported in 69 out of 77 provinces, indicating a serious nationwide situation. Understanding the dynamics of spatial and temporal LSD epidemic patterns can provide important information on disease transmission and control. This study aims to identify spatial and temporal clusters in the first LSD outbreaks in dairy farming areas with a high degree of aggregation in Northern Thailand using spatio-temporal models. The data were obtained from an official LSD outbreak investigation conducted between June and August 2021 on dairy farms (n = 202). The outbreak of LSD was confirmed by employing clinical observations and laboratory analysis. The spatio-temporal models including space-time permutation (STP), Poisson, and Bernoulli were applied to the outbreak data with the settings of 10%, 25%, and 50%, respectively, for the maximum reported cluster size (MRCS). Overall, the number of most likely and secondary clusters varied depending on the model and MRCS settings. All MRCS settings in the STP model detected the most likely clusters in the same area and the Poisson models in different areas, with the largest being defined by a 50% MRCS. Although the sizes of the most likely clusters identified by the Bernoulli models were different, they all had the same cluster period. Based on the sizes of the detected clusters, strict LSD insect-vector control should be undertaken within one kilometer of the outbreak farm in areas where no LSD vaccination has been administered. This study determines the sizes and patterns of LSD outbreak clusters in the dairy farming area with a high degree of farm aggregation. The spatio-temporal study models used in this study, along with multiple adjusted MRCS, provide critical epidemiological information. These models also expand the options for assisting livestock authorities in facilitating effective LSD prevention and control programs. By prioritizing areas for resource allocation, these models can help improve the efficiency of such programs.

Estimating the Transmission Kernel for Lumpy Skin Disease Virus from Data on Outbreaks in Thailand in 2021

Nationwide outbreaks of lumpy skin disease (LSD) were observed in Thailand in 2021. A better understanding of its disease transmission is crucial. This study utilized a kernel-based approach to characterize the transmission of LSD between cattle herds. Outbreak data from the Khon Kaen and Lamphun provinces in Thailand were used to estimate transmission kernels for each province. The results showed that the majority of herd-to-herd transmission occurs over short distances. For Khon Kaen, the median transmission distance from the donor herd was estimated to be between 0.3 and 0.8 km, while for Lamphun, it ranged from 0.2 to 0.6 km. The results imply the critical role that insects may play as vectors in the transmission of LSD within the two study areas. This is the first study to estimate transmission kernels from data on LSD outbreaks in Thailand. The findings from this study offer valuable insights into the spatial transmission of this disease, which will be useful in developing prevention and control strategies.

Global Burden of Lumpy Skin Disease, Outbreaks, and Future Challenges

Lumpy skin disease (LSD), a current global concern, causes economic devastation in livestock industries, with cattle and water buffalo reported to have higher morbidity and lower mortality rates. LSD is caused by lumpy skin disease virus (LSDV), a member of the Poxviridae family. It is an enzootic, rapidly explorative and sometimes fatal infection, characterized by multiple raised nodules on the skin of infected animals. It was first reported in Zambia in 1929 and is considered endemic in Africa south of the Sahara desert. It has gradually spread beyond Africa into the Middle East, with periodic occurrences in Asian and East European countries. Recently, it has been spreading in most Asian countries including far East Asia and threatens incursion to LSD-free countries. Rapid and accurate diagnostic capabilities, virus identification, vaccine development, vector control, regional and international collaborations and effective biosecurity policies are important for the control, prevention, and eradication of LSD infections. This review critically evaluates the global burden of LSD, the chronological historical outbreaks of LSD, and future directions for collaborative global actions.

First complete genome sequence of lumpy skin disease virus directly from a clinical sample in South India

Lumpy skin disease (LSD), a notifiable disease listed by the World Organization for Animal Health and a fast fast-moving transboundary viral disease infecting cattle and buffaloes, was reported in India in 2019 and has since rapidly spread across the country. This study reports the first complete genome sequence and analysis of a pathogenic LSD virus (LSDV) from India (LSDV/208/PVNRTVU/2020) obtained by direct sequencing of a suspected clinical sample using Illumina and Nanopore sequencing technologies. The complete genome sequence of LSDV/208/PVNRTVU/2020 is 150445 bp long, codes for 156 putative genes and carries identical 2254 bp inverted terminal repeats at either ends. The unique features reported in the LSDV isolates from the recent outbreaks in Asia, namely, the insertions of 12 nucleotides in the viral G-protein coupled receptor (GPCR) and 27 nucleotides leading to duplication of 9 aminoacids in the extracellular enveloped virus-specific (EEV) genes were also conserved in LSDV/208/PVNRTVU/2020. Phylogenetic analysis of the complete genome sequence of LSDV/208/PVNRTVU/2020 revealed its close relation with Kenyan strains and clustered away from vaccine strains. Further analysis showed evidence of strong purifying selection without any recombination events. The data presented in this study could be useful for designing effective strategies such as developing rapid diagnostics and vaccines to control LSD.

Development of a dual vaccine against East Coast fever and lumpy skin disease

East Coast fever is an acute bovine disease caused by the apicomplexan parasite Theileria parva and is regarded as one of the most important tick-vectored diseases in Africa. The current vaccination procedure has many drawbacks, as it involves the use of live T. parva sporozoites. As a novel vaccination strategy, we have constructed the recombinant lumpy skin disease virus (LSDV) named LSDV-SODis-p67HA-BLV-Gag, encoding a modified form of the T. parva p67 surface antigen (p67HA), as well as the bovine leukemia virus (BLV) gag gene for the formation of virus-like particles (VLPs) to potentially enhance p67 immunogenicity. In place of the native sequence, the chimeric p67HA antigen has the human tissue plasminogen activator signal sequence and the influenza hemagglutinin A2 transmembrane domain and cytoplasmic tail. p67HA was detected on the surface of infected cells, and VLPs comprising BLV Gag and p67HA were produced. We also show that higher multiple bands observed in western blot analysis are due to glycosylation of p67. The two vaccines, pMExT-p67HA (DNA) and LSDV-SODis-p67HA-BLV-Gag, were tested for immunogenicity in mice. p67-binding antibodies were produced by vaccinated animals, with higher titers detected in mice vaccinated with the recombinant LSDV. This candidate dual vaccine warrants further testing in cattle.

Development and Validation of a New DIVA Real-Time PCR Allowing to Differentiate Wild-Type Lumpy Skin Disease Virus Strains, Including the Asian Recombinant Strains, from Neethling-Based Vaccine Strains

The current epidemic in Asia, driven by LSDV recombinants, poses difficulties to existing DIVA PCR tests, as these do not differentiate between homologous vaccine strains and the recombinant strains. We, therefore, developed and validated a new duplex real-time PCR capable of differentiating Neethling-based vaccine strains from classical and recombinant wild-type strains that are currently circulating in Asia. The DIVA potential of this new assay, seen in the in silico evaluation, was confirmed on samples from LSDV infected and vaccinated animals and on isolates of LSDV recombinants (n = 12), vaccine (n = 5), and classic wild-type strains (n = 6). No cross-reactivity or a-specificity with other capripox viruses was observed under field conditions in non-capripox viral stocks and negative animals. The high analytical sensitivity is translated into a high diagnostic specificity as more than 70 samples were all correctly detected with Ct values very similar to those of a published first-line pan capripox real-time PCR. Finally, the low inter- and intra-run variability observed shows that the new DIVA PCR is very robust which facilitates its implementation in the lab. All validation parameters that are mentioned above indicate the potential of the newly developed test as a promising diagnostic tool which could help to control the current LSDV epidemic in Asia.

An Extensive Examination of the Warning Signs, Symptoms, Diagnosis, Available Therapies, and Prognosis for Lumpy Skin Disease

The lumpy skin disease virus (LSDV) infects cattle and buffalo and causes lumpy skin disease (LSD). It affects the lymph nodes of the sick animals, causing them to enlarge and appear as lumps (cutaneous nodules) that are 2–5 cm in diameter on their heads, necks, limbs, udders, genitalia, and perinea. A high temperature, a sharp drop in milk supply, discharge from the eyes and nose, salivation, a loss of appetite, depression, damaged hides, and emaciation are further warning signs and symptoms. As per the Food and Agriculture Organization (FAO), the incubation period, or the time between an infection and symptoms, is approximately 28 days. Infected animals can transfer the virus by direct contact with the vectors, direct virus secretion from mouth or nose, shared feeding and watering troughs, and even artificial insemination. The World Organization for Animal Health (WOAH) and the FAO both warn that the spread of illnesses could lead to serious economic losses. This illness reduces cow’s milk production because oral ulcers make the animal weak and lead them to lose their appetite. There are many diagnostics available for LSDV. However, very few tests yield accurate findings. The best methods for preventing and controlling the lumpy skin condition include vaccination and movement restrictions. As a specific cure is not available, the only available treatment for this illness is supportive care for cattle. Recently, India has developed a homologous, live-attenuated vaccine, Lumpi-ProVacInd, which is specifically intended to protect animals against the LSD virus. This study’s primary goal is to accumulate data on symptoms, the most accurate method of diagnosis, treatments, and controls to stop infections from spreading as well as to explore future possibilities for the management of LSDV.

Biochemical Analysis of the Blood of Cattle after Vaccination with a Heterologous Vaccine for Lumpy Skin Disease

We studied the biochemical parameters of the blood of cattle after immunization against lumpy skin disease with a vaccine made from an attenuated heterologous goat pox virus (strain G₂₀-LKV). Blood samples were obtained from animals on days 7, 14, and 21 after vaccination. The vaccine did not affect biochemical parameters of the blood. A slight increase in total protein and AST on day 14 indicates the expected reactions to the stimulation of the immune system after vaccination. The levels of direct and total bilirubin, ALT, urea, glucose, cholesterol, and creatinine in vaccinated animals remained within the physiological limits.

Evidence of recombination of vaccine strains of lumpy skin disease virus with field strains, causing disease

Vaccination against lumpy skin disease (LSD) is crucial for maintaining the health of animals and the economic sustainability of farming. Either homologous vaccines consisting of live attenuated LSD virus (LSDV) or heterologous vaccines consisting of live attenuated sheeppox or goatpox virus (SPPV/GPPV) can be used for control of LSDV. Although SPPV/GTPV-based vaccines exhibit slightly lower efficacy than live attenuated LSDV vaccines, they do not cause vaccine-induced viremia, fever, and clinical symptoms of the disease following vaccination, caused by the replication capacity of live attenuated LSDVs. Recombination of capripoxviruses in the field was a long-standing hypothesis until a naturally occurring recombinant LSDV vaccine isolate was detected in Russia, where the sheeppox vaccine alone is used. This occurred after the initiation of vaccination campaigns using LSDV vaccines in the neighboring countries in 2017, when the first cases of presumed vaccine-like isolate circulation were documented with concurrent detection of a recombinant vaccine isolate in the field. The follow-up findings presented herein show that during the period from 2015 to 2018, the molecular epidemiology of LSDV in Russia split into two independent waves. The 2015-2016 epidemic was attributable to the field isolate. Whereas the 2017 epidemic and, in particular, the 2018 epidemic represented novel disease importations that were not genetically linked to the 2015-2016 field-type incursions. This demonstrated a new emergence rather than the continuation of the field-type epidemic. Since recombinant vaccine-like LSDV isolates appear to have entrenched across the country's border, the policy of using certain live vaccines requires revision in the context of the biosafety threat it presents.

An investigation of the seroprevalence of CrimeanCongo Hemorrhagic Fever and Lumpy Skin Disease in domesticated water buffaloes in northern Turkey

This study was conducted in Samsun Province of Turkey to investigate the serological status of domesticated water buffaloes for both Crimean-Congo Hemorrhagic Fever (CCHF) and Lumpy Skin Disease (LSD). Serum was collected from a total of 272 water buffaloes from different age groups and both genders; of the total, 48.1% had been vaccinated against LSD with heterologous sheep-goat pox vaccine. The serum samples were individually assessed by using a commercial ID screen enzyme-linked immune-sorbent assay (ELISA) to detect neutralizing antibodies against both CCHF virus and LSD virus. All 272 buffaloes were negative for antibodies against the CCHF virus. All the unvaccinated buffaloes (141) were seronegative for LSD virus but of the 131 vaccinated buffaloes, 10 (7.6%) were seropositive for the LSD virus. In addition, 8.6% of vaccinated animals age >1 year old were seropositive for LSD, whereas the seropositivity was 5.1% for the animals age <= 1 year old. There was no significant difference for seropositivity between male and female animals in the >1 year old or <= 1 year old age groups. When seroprevalances for LSD in the tested water buffaloes are evaluated by gender, there was a significant difference between females (8.6%) and males (0%) in the <1 year old water buffaloes (X²=20.24; P<0.001). Separately, the results of this study indicate that Bafra district water buffaloes are not infected by CCHFV and LSDV and some of the buffaloes that vaccinated with LSDV did not develop sufficient antibodies to protect them after they were vaccinated for the LSD virus. Furthermore, the authors of this study conclude that both the commercially produced vaccine that is currently administered and the vaccination strategy have to be urgently evaluated by the veterinary authorities in Turkey. This is essential in order to combat the spread of LSD virus infection with an effective vaccine and a comprehensive management strategy across Turkey.

Humoral immune response to repeated lumpy skin disease virus vaccination and performance of serological tests

BACKGROUND

In the presented study we investigated the development of the humoral immune response against LSDV during the process of re-vaccination of cattle over a time span of 5 months. In addition, the performance of different serological techniques for antibody detection against LSDV was compared. For sample collection, an area without previous LSD outbreak reports in Serbia was selected. Seventy-nine cattle from twenty farms vaccinated in 2016 and re-vaccinated in 2017 were included in the study. Two farms from the same area with good calving management were selected for investigation of passive LSDV antibody transfer from vaccinated mothers to new-borne calves.

RESULTS

All investigated cattle were healthy on the day of vaccination and during the whole study. Swelling at the injection site or other side effects of vaccination did not occur after re-vaccination in the study. Detection of LSD-specific antibodies was performed with the standard serological methods VNT and IFAT as well as a commercially available Capripox double antigen multi-species-ELISA. Capripoxvirus-specific antibodies were detected 46 to 47 weeks after vaccination in 2016, with VNT in 35.06% and with IFAT and ELISA in 33.77%. A secondary response was observed in all three tests 1 month after re-vaccination with a significant increase in seropositive animals compared to the results before re-vaccination. With all applied serological methods, the number of animals testing positive was significantly higher at 1 and 5 months post re-vaccination than before re-vaccination. No significant statistical difference (p > 0.05) was observed between the results of all three tests used. The sensitivity and specificity of ELISA was estimated to be SeELISA 91% and SpELISA 87% calculated by the results of VNT and SeELISA 88% and SpELISA 76% calculated by the results of IFAT. Passive antibody transfer from vaccinated mothers to new-born calves was investigated at 14 days after birth. Discrepancies for the detection of LSDV specific antibodies between cows and newborn calves at the age of 14 days were observed in VNT and IFAT, but not in ELISA.

CONCLUSION

Of all tests used the commercially available ELISA shows to be the most useful for high throughput analysis compared to VNT or IFAT.

A simple method to estimate the number of doses to include in a bank of vaccines. The case of Lumpy Skin Disease in France

A simple method to estimate the size of the vaccine bank needed to control an epidemic of an exotic infectious disease in case of introduction into a country is presented. The method was applied to the case of a Lumpy Skin disease (LSD) epidemic in France. The size of the stock of vaccines needed was calculated based on a series of simple equations that use some trigonometric functions and take into account the spread of the disease, the time required to obtain good vaccination coverage and the cattle density in the affected region. Assuming a 7-weeks period to vaccinate all the animals and a spread of the disease of 7.3 km/week, the vaccination of 740 716 cattle would be enough to control an epidemic of LSD in France in 90% of the simulations (608 196 cattle would cover 75% of the simulations). The results of this simple method were then validated using a dynamic simulation model, which served as reference for the calculation of the vaccine stock required. The differences between both models in different scenarios, related with the time needed to vaccinate the animals, ranged from 7% to 10.5% more vaccines using the simple method to cover 90% of the simulations, and from 9.0% to 13.8% for 75% of the simulations. The model is easy to use and may be adapted for the control of different diseases in different countries, just by using some simple formulas and few input data.

Tick-Borne Diseases in Turkey: A Review Based on One Health Perspective

The importance of tick-borne diseases is increasing all over the world, including Turkey. Global warming, environmental and ecological changes and the existence of suitable habitats increase the impact of ticks and result in frequent emergence or re-emergence of tick-borne diseases (TBDs) with zoonotic characteristics. In Turkey, almost 19 TBDs have been reported in animals and men, involving four protozoa (babesiosis, theileriosis, cytauxzoonosis, hepatozoonosis), one filarial nematode (acanthocheilonemasis), ten bacterial agents (anaplasmosis, ehrlichiosis, aegyptianellosis, tick-borne typhus, Candidatus Rickettsia vini, Lyme borreliosis, tick-borne relapsing fever [TBRF], tularaemia, bartonellosis, and hemoplasmosis), and four viral infections (tick-borne encephalitis [TBE], Crimean-Congo Haemorrhagic Fever [CCHF], louping-ill [LI], and lumpy skin disease [LSD]). The growing number of TBD cases, in particular the fatal viral epidemics in humans, have led to increased public awareness and concern against TBDs in recent years. The World Health Organization (WHO) has developed a new political concept, called the "One Health" initiative, which is especially relevant for developing strategies against tick infestations and TBD control in humans and animals. It would be beneficial for Turkey to adopt this new strategy and establish specific research and control programs in coordination with international organizations like WHO, the World Organization for Animal Health (OIE), the Food and Agriculture Organization (FAO), the Centers for Disease Control and Prevention (CDC), and the European Center for Disease Prevention and Control (ECDC) to combat TBDs based on the "One Health Initiative" concept. In this article, we review the occurrence of primary TBDs in man and animals in Turkey in light of the "One Health" perspective.

Comparison of the efficacy of Neethling lumpy skin disease virus and x10RM65 sheep-pox live attenuated vaccines for the prevention of lumpy skin disease - The results of a randomized controlled field study

Lumpy skin disease (LSD) is a viral disease of cattle and buffalo, caused by a Capripox virus. A field study was performed during an LSD epidemic which occurred in 2012-2013 in Israel, in order to assess the efficacy of two commercial vaccines for protection against LSD. Fifteen dairy herds, vaccinated 2-5 months prior to study onset with a single dose of 10(2.5) TCID50 of RM65 attenuated sheep-pox vaccine, and not affected previously, were enrolled in the study. 4694 cows were randomized to be either vaccinated with a 10(3.5) TCID50/dose of RM65 vaccine (x10RM65) or with a same dose of an attenuated Neethling LSD virus vaccine. A case of LSD was defined as the appearance of at least 5 lesions typical to LSD and a severe case was defined if this sign was accompanied by either fever (>39.5°C) or/and a 20% reduction in milk production. Deep lesion biopsies and blood samples were collected from 64.5% of the cases in an attempt to detect DNA of LSD virus by PCR and to differentiate between the wild strain and the vaccine Neethling strain. Seventy-six cows were affected by LSD in 8 herds with an incidence of 0.3-5.7%. Mantel-Haenszel relative risk (RRMH) for LSD morbidity at least 15 days after vaccination in x10RM65 vs. Neethling was 2.635 (CI95%=1.44-4.82) and 11.2 (2.3-54.7) for severe morbidity. RRMH for laboratory confirmed cases was 4.28 (1.59-11.53). An incidence of 0.38% (9/2356) of Neethling associated disease was observed among Neethling vaccinated cows while no such disease occurred in x10RM65 vaccinated cows. We conclude that the Neethling vaccine is significantly more effective than x10RM65 in preventing LSD morbidity, though it might cause a low incidence of Neethling associated disease. No transmission of the Neethling strain to non-Neethling vaccinated cows was observed in this study.

Lumpy skin disease in cattle in central Ethiopia: outbreak investigation and isolation and molecular detection of the virus

The study was a combination of two investigations into active outbreaks of lumpy skin disease (LSD) in cattle in central Ethiopia and a retrospective analysis of outbreak reports between January 2007 and December 2011 covering the entire country. Active outbreaks were investigated in four districts of central Ethiopia: Adama, Wenji, Mojo and Welenchiti. A semi-structured questionnaire was used to acquire data at individual and herd levels, and tissue samples were collected for viral isolation and characterisation. The retrospective analyses showed that, during the five-year period, a total of 1,675 outbreaks were reported, with 62,176 cases and 4,372 deaths. The highest number of outbreaks was reported in Oromia (1,066), followed by Amhara (365) and the Southern Nations, Nationalities and People's Region (123). Outbreaks were more frequently observed between September and December and the highest number of outbreaks was reported in 2010. During the period studied, a total of 2,174 local zebu cattle were clinically examined and morbidity and mortality rates of 13.61% (296) and 4.97% (108) were recorded, respectively. Analysis of the active outbreaks revealed a relatively consistent morbidity rate, with the highest observed in Adama (15.38%), followed by Wenji (10.26%). The highest mortality rates were also observed in Adama (5.89%) and Wenji (3.42%). The LSD virus was isolated from 22 samples and all tested positive in polymerase chain reaction analysis. The disease was observed in the cattle regardless of previous vaccination with Kenyan sheep- and goat-pox vaccine; thus, vaccine efficacy was assessed under field conditions and the authors' findings, together with a possible remedy, are presented in this paper.

Characterization of sheep pox virus vaccine for cattle against lumpy skin disease virus

Lumpy skin disease is of significant economic impact for the cattle industry in Africa. The disease is currently spreading aggressively in the Near East, posing a threat of incursion to Europe and Asia. Due to cross-protection within the Capripoxvirus genus, sheep pox virus (SPPV) vaccines have been widely used for cattle against lumpy skin disease virus (LSDV). In the Middle East and the Horn of Africa these vaccines have been associated with incomplete protection and adverse reactions in cattle post-vaccination. The present study confirms that the real identity of the commonly used Kenyan sheep and goat pox vaccine virus (KSGP) O-240 is not SPPV but is actually LSDV. The low level attenuation of this virus is likely to be not sufficient for safe use in cattle, causing clinical disease in vaccinated animals. In addition, Isiolo and Kedong goat pox strains, capable of infecting sheep, goats and cattle are identified for potential use as broad-spectrum vaccine candidates against all capripox diseases.

Comparative sequence analysis of the South African vaccine strain and two virulent field isolates of Lumpy skin disease virus

The genomic sequences of 3 strains of Lumpy skin disease virus (LSDV) (Neethling type) were compared to determine molecular differences, viz. the South African vaccine strain (LW), a virulent field-strain from a recent outbreak in South Africa (LD), and the virulent Kenyan 2490 strain (LK). A comparison between the virulent field isolates indicates that in 29 of the 156 putative genes, only 38 encoded amino acid differences were found, mostly in the variable terminal regions. When the attenuated vaccine strain (LW) was compared with field isolate LD, a total of 438 amino acid substitutions were observed. These were also mainly in the terminal regions, but with notably more frameshifts leading to truncated ORFs as well as deletions and insertions. These modified ORFs encode proteins involved in the regulation of host immune responses, gene expression, DNA repair, host-range specificity and proteins with unassigned functions. We suggest that these differences could lead to restricted immuno-evasive mechanisms and virulence factors present in attenuated LSDV strains. Further studies to determine the functions of the relevant encoded gene products will hopefully confirm this assumption. The molecular design of an improved LSDV vaccine is likely to be based on the strategic manipulation of such genes.

Vaccines for lumpy skin disease, sheep pox and goat pox

Sheep pox, goat pox and lumpy skin disease (Neethling) are diseases of sheep, goats and cattle respectively, caused by strains of poxvirus, within the genus Capripoxvirus. Strains affecting sheep and goats are not totally host-specific; some cause disease in both sheep and goats while others may cause disease in only one species. Those causing disease in cattle appear to be specific for cattle, and this is reflected in the different geographical distribution of lumpy skin disease (LSD) and sheep pox and goat pox (sheep and goat pox); LSD is confined to Africa, while sheep and goat pox are present in Africa north of the equator, and throughout West Asia and India, as far East as China and Bangladesh. Occasionally sheep and goat pox spreads from Turkey into Greece. All strains of capripoxvirus so far examined are antigenically indistinguishable, and recovery from infection with one strain provides immunity against all other strains. Because of this antigenic homology among all strains, there is the potential to use a single vaccine strain to protect cattle, sheep and goats.

Lumpy skin disease in southern Africa: a review of the disease and aspects of control

This article reviews some of the important aspects of lumpy skin disease (LSD) that may impact on its successful control. A resurgence of the disease in the last decade has highlighted some constraints of the Neethling strain vaccine, but there is no evidence of vaccine breakdowns owing to the presence of heterologous field strains. More research is needed on epidemiology and transmission of LSD in South Africa to formulate control measures.

Trial of a capripoxvirus-rinderpest recombinant vaccine in African cattle

Cattle were vaccinated with differing doses of an equal mixture of capripox-rinderpest recombinant viruses expressing either the fusion protein (F) or the haemagglutinin protein (H) of rinderpest virus. Animals vaccinated with 2 x 10(4) p.f.u. or greater of the combined viruses were completely protected against challenge, 1 month later, with both virulent rinderpest and lumpy skin disease viruses. Vaccination with any of the doses did not induce any adverse clinical response in the animals or transmission of the vaccine virus between animals. All cattle challenged 6 or 12 months after vaccination with 2 x 10(5) p.f.u. of the mixture of recombinant viruses were protected from severe rinderpest disease. Ten out of 18 were completely protected while the remaining 8 developed mild clinical signs of rinderpest. Cattle vaccinated with the recombinant vaccines after prior infection with the parental capripox virus showed more marked clinical signs of rinderpest after challenge with virulent rinderpest, but 9 out of 10 recovered, compared with 80% mortality in the unvaccinated controls.

Spread of lumpy skin disease in Israeli dairy herds

Fourteen of the 17 dairy herds in Peduyim, an Israeli village, became infected with lumpy skin disease during a period of 37 days in August and September 1989. One cow in one neighbouring village and four cows in another neighbouring village also became infected, probably through being treated by a veterinarian who treated cows in Peduyim. Circumstantial evidence suggests that the original infection was brought to Peduyim and spread by stable flies (Stomoxys calcitrans) carried by the wind from foci of the disease at El Arish in northern Sinai, or at Ismailiya and the Nile delta in Egypt. All the cattle and the small flocks of sheep and goats in the village were slaughtered.

Recombinant capripoxvirus expressing the hemagglutinin protein gene of rinderpest virus: protection of cattle against rinderpest and lumpy skin disease viruses

A cDNA clone containing the complete coding sequence of the hemagglutinin (H) protein gene of the RBOK vaccine strain of rinderpest virus, under the control of the vaccinia late promoter p11, was inserted by homologous recombination into the thymidine kinase gene of the KS-1 strain of capripoxvirus. The recombinant virus produced authentic H protein as judged by its electrophoretic mobility, transport to the cell surface of infected lamb testis cells, and reactivity with monoclonal antibodies specific for the H protein of rinderpest virus. The recombinant virus induced significant levels of rinderpest virus neutralizing antibodies in vaccinated cattle and protected them from clinical rinderpest after challenge with a lethal dose of a highly virulent heterologous strain of the virus. Protection was achieved using vaccine doses lower than those used with a similar recombinant expressing the fusion protein gene of rinderpest. The parental KS-1 virus is widely used as a vaccine against capripox viruses and so the rinderpest recombinant acts as a dual vaccine to protect cattle against both rinderpest and lumpy skin disease.

Adverse reactions in cattle to a capripox vaccine

Capripox vaccine (strain 0240) caused severe generalised skin reactions in vaccinated dairy cattle in two herds, whereas beef cattle did not develop reactions. All the reacting animals developed lumpy skin disease-like lesions. The incidence of skin lesions in first-lactation cows in herd A was 22.9 per cent and in herd B 29.3 per cent, mainly in the post-calving period. In older cows, the incidence was 10 per cent in herd A and 12.4 per cent in herd B. In herd B the high-yielding lactating cows were the most severely affected. There was a decrease of 3.5 per cent in milk production in each herd over a period of 12 days, and six first calving animals (3.5 per cent) and six cows (1.5 per cent) were slaughtered. A capripox virus was isolated from the animals with severe lesions, and was also demonstrated by electron microscopy. The histopathological lesions were similar to those of lumpy skin disease. The extent of the lesions appeared to be stress-related and, to a lesser degree, correlated with age and breed.

Protection of cattle against rinderpest and lumpy skin disease with a recombinant capripoxvirus expressing the fusion protein gene of rinderpest virus

Cattle were protected against challenge with rinderpest and lumpy skin disease viruses by vaccination with a recombinant capripoxvirus containing the fusion protein (F) gene of rinderpest virus. The minimum protective immunising doses for rinderpest and lumpy skin disease were 5.5 x 10(4) plaque forming units (pfu) and 1.5 x 10(3) pfu, respectively.

Single capripoxvirus recombinant vaccine for the protection of cattle against rinderpest and lumpy skin disease

A recombinant capripoxvirus has been constructed containing a full-length cDNA of the fusion protein gene of rinderpest virus. The gene was inserted in the thymidine kinase gene of the capripox genome under the control of the vaccinia virus major late promoter p11 together with the Escherichia coli gpt gene in the opposite orientation under the control of the vaccinia early/late promoter p7.5. A vaccine prepared from this recombinant virus protected cattle against clinical rinderpest after a lethal challenge with a virulent virus isolate. In addition, the vaccine protected the cattle against lumpy skin disease.

Lumpy skin disease, an African capripox virus disease of cattle

Lumpy skin disease is an infectious viral disease of cattle, which often occurs in epizootic form. The disease is characterized by the eruption of nodules in the skin, which may cover the whole of the animal's body. Systemic effects include pyrexia, anorexia, dysgalactia and pneumonia; lesions are often found in the mouth and upper respiratory tract. The severity of the disease varies considerably between breeds and strains of cattle. Many cattle suffer severe emaciation and loss of production for several months. The skin lesions cause permanent damage to the hides. The mode of transmission of the disease has not been clearly established. Contact infections do not readily occur and the evidence from the epizootiology strongly suggests that insect vectors are involved. The disease has been confined to sub-Saharan Africa, until it recently appeared in epizootic form in Egypt and in Israel. Transmission occurs in a wide variety of biotypes, from semi-desert to temperate grasslands and irrigated land. It has the potential to extend its range further.