A vero cell derived combined vaccine against sheep pox and Peste des Petits ruminants for sheep

Development of cell culture based peste des petits ruminants (PPR) virus vaccine candidate from Bangladeshi isolates

This study was conducted to develop a cell culture based PPR virus vaccine candidate using recent Bangladeshi strain of peste des petits ruminant's (PPR) virus. PPR virus was isolated from field outbreaks, confirmed by RT-PCR and used as viral inoculum for serial passaging in Vero cells for adaptation and attenuation. 60th serial passage had completed and RT-PCR and real time RT-PCR were done in every 5 passages for confirmation of PPR virus in tissue culture fluid (TCF). To assess the adaptation and attenuation cytopathology, virus titration, sequencing of both F and N genes and live animal experimentation were done. Different cellular alterations produced by PPR virus in infected Vero cells including syncytia formation, development of both intranuclear and intra cytoplasmic inclusion bodies and finally cell degradation are the indications of adaptation. The virus titre was found 2.5, 3.31, 3.55, 4.44, 4.71 and 6.5 Log₁₀ TCID₅₀/ml at 10th, 20th, 30th, 40th, 50th and 60th passages level respectively. In F gene sequence analysis it has been observed that few nucleotide (nt) and mino acid (aa) has been substituted as the effects of serial passaging of PPR virus in Vero cells. TCF at 60th passage level was found effective to produced protective antibody (Ab) titre in live animal experimentation. It is concluded that serially passaged and Vero cells adapted PPR virus TCF could be used as a vaccine candidate for further use to develop a potent & effective vaccine against PPR diseases.

The Development of a Real-Time PCR Assay for Specific Detection of the NISKHI Sheep Pox Vaccine Virus Strain DNA

Sheep pox (SPP) constitutes a global animal health scourge, despite the numerous efforts targeting the eradication of the disease implemented in affected countries. An efficient control and eradication strategy incorporates the use of live attenuated vaccines, which in turn requires a method for differentiation between vaccinated and infected sheep. The NISKHI live attenuated SPP vaccine (LAV) is abundantly used in Russia, Kazakhstan and other Central Asian countries. This study describes the development and evaluation of a real-time PCR with a high-resolution melting assay, capable of differentiating the NISKHI vaccine virus from circulating virulent field strains. The RNA polymerase subunit RPO132 gene contains a unique single nucleotide polymorphism (SNP) capable of altering the melting curves of amplicons from LAV and virulent field isolates circulating in the region. The melting temperature (Tm) of field isolates ranged from 75.47 °C ± 0.04 to 75.86 °C ± 0.08, while the vaccine strain averaged 76.46 °C ± 0.12. Subsequent evaluation of this assay demonstrated that the recent SPP outbreaks in central Russia may be attributed to virulent field isolates. This robust assay was proven to consistently and differentially detect the NISKHI LAV strain when analyzing clinical samples from affected sheep.

Comparison and efficacy of two different sheep pox vaccines prepared from the Bakırköy strain against lumpy skin disease in cattle

Purpose

Materials and Methods

Results

Conclusion

Assessment of the control measures of the category A diseases of Animal Health Law: sheep and goat pox

EFSA received a mandate from the European Commission to assess the effectiveness of some of the control measures against diseases included in the Category A list according to Regulation (EU) 2016/429 on transmissible animal diseases ('Animal Health Law'). This opinion belongs to a series of opinions where these control measures will be assessed, with this opinion covering the assessment of control measures for sheep and goat pox. In this opinion, EFSA and the AHAW Panel of experts review the effectiveness of: (i) clinical and laboratory sampling procedures, (ii) monitoring period and (iii) the minimum radii of the protection and surveillance zones, and the minimum length of time the measures should be applied in these zones. The general methodology used for this series of opinions has been published elsewhere; nonetheless, the transmission kernels used for the assessment of the minimum radii of the protection and surveillance zones are shown. Several scenarios for which these control measures had to be assessed were designed and agreed prior to the start of the assessment. Different risk-based sampling procedures based on clinical visits and laboratory testing are assessed in case of outbreak suspicion, granting animal movements and for repopulation purposes. The monitoring period of 21 days was assessed as effective. The estimated probability of transmission beyond the protection zone of 3 km radius from an infectious establishment is 9.6% (95% CI: 3.1-25.8%) and 2.3% (95% CI: 1-5.5%) for the surveillance zone of 10 km radius. This may be considered sufficient to contain the disease spread (95% probability of containing transmission corresponds to 5.3 Km). To contain 99% of the spread, the radius should be increased to 19.4 km (95% CI: 9.8-26.8). This may increase the number of farms in the surveillance zone, since the area would increase fourfold.

Duration of Protective Immunity in Sheep Vaccinated with a Combined Vaccine against Peste des Petits Ruminants and Sheep Pox

In this study, the ability of the combined vaccine against peste des petits ruminants (PPR) (Nigeria strain 75/1) and sheep pox (SPP) (NISKhI strain) to form a protective immune response for 12 months in Kazakh breed fine-fleeced sheep aged 6–12 months was demonstrated. The duration of the protective immunity of immunized sheep from PPR and from SPP was evaluated using a serum neutralization test (SNT), followed by testing of the resistance of vaccinated sheep to infection with the field strain Kentau-7 of the PPRV and the virulent strain A of the SPPV. The PPR antibody response was additionally measured by c-ELISA. A single immunization of sheep with a combined vaccine in a volume of 2.0 mL, containing the PPR and SPP vaccine viruses in the titers of 10^3.0 TCID₅₀/mL, provided reliable protection of animals from two infections simultaneously for 12 months (observation period). At the same time, in sheep immunized with the combined vaccine, antibodies of PPRV persisted for up to 12 months, with slight fluctuations. The combined vaccine induced 100% clinical protection against the field strain of PPRV and the virulent strain of SPPV in immunized sheep for up to 12 months, while unvaccinated animals became ill with the manifestation of clinical signs specific to PPRV and SPPV.

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.

In vitro and in vivo analyses of co-infections with peste des petits ruminants and capripox vaccine strains

BACKGROUND

Peste des petits ruminants (PPR) and goat pox (GTP) are two devastating animal epidemic diseases that affect small ruminants. Vaccination is one of the most important measures to prevent and control these two severe infectious diseases.

METHODS

In this study, we vaccinated sheep with PPR and POX vaccines to compare the changes in the antibody levels between animals vaccinated with PPRV and POX vaccines alone and those co-infected with both vaccines simultaneously. The cell infection model was used to explore the interference mechanism between the vaccines in vitro. The antibody levels were detected with the commercial ELISA kit. The Real-time Quantitative PCR fluorescent quantitative PCR method was employed to detect the viral load changes and cytokines expression after the infection.

RESULTS

The concurrent immunization of GTP and PPR vaccine enhanced the PPR vaccine's immune effect but inhibited the immune effect of the GTP vaccine. After the infection, GTP and PPR vaccine strains caused cytopathic effect; co-infection with GTP and PPR vaccine strains inhibited the replication of PPR vaccine strains; co-infection with GTP and PPR vaccine strains enhanced the replication of GTP vaccine strains. Moreover, virus mixed infection enhanced the mRNA expressions of TNF-α, IL-1β, IL-6, IL-10, IFN-α, and IFN-β by 2-170 times. GTP vaccine strains infection alone can enhanced the mRNA expression of IL-1β, TNF-α, IL-6, IL-10, while the expression of IFN-α mRNA is inhibited. PPR vaccine strains alone can enhanced the mRNA expression of IFN-α, IFN-β, TNF-α, and has little effect the mRNA expression of IL-1β, IL-6 and IL-10. The results showed that GTP and PPR vaccine used simultaneously in sheep enhanced the PPR vaccine's immune effect but inhibited the immune effect of the GTP vaccine in vivo. Furthermore, an infection of GTP and PPR vaccine strains caused significant cell lesions in vitro; co-infection with GTP + PPR vaccine strains inhibited the replication of PPR vaccine strains, while the co-infection of GTP followed by PPR infection enhanced the replication of GTP vaccine strains. Moreover, virus infection enhanced the expressions of TNF-α, IL-1β, IL-6, IL-10, IFN-α, and IFN-β.

CONCLUSIONS

Peste des petits ruminants and capripox vaccine strains interfere with each other in vivo and vitro.

Future research to underpin successful peste des petits ruminants virus (PPRV) eradication

Peste des petits ruminants virus (PPRV) is a significant pathogen of small ruminants and is prevalent in much of Africa, the Near and Middle East and Asia. Despite the availability of an efficacious and cheap live-attenuated vaccine, the virus has continued to spread, with its range stretching from Morocco in the west to China and Mongolia in the east. Some of the world's poorest communities rely on small ruminant farming for subsistence and the continued endemicity of PPRV is a constant threat to their livelihoods. Moreover, PPRV's effects on the world's population are felt broadly across many economic, agricultural and social situations. This far-reaching impact has prompted the Food and Agriculture Organization of the United Nations (FAO) and the World Organisation for Animal Health (OIE) to develop a global strategy for the eradication of this virus and its disease. PPRV is a morbillivirus and, given the experience of these organizations in eradicating the related rinderpest virus, the eradication of PPRV should be feasible. However, there are many critical areas where basic and applied virological research concerning PPRV is lacking. The purpose of this review is to highlight areas where new research could be performed in order to guide and facilitate the eradication programme. These areas include studies on disease transmission and epidemiology, the existence of wildlife reservoirs and the development of next-generation vaccines and diagnostics. With the support of the international virology community, the successful eradication of PPRV can be achieved.

Advances in peste des petits ruminants vaccines

Peste des petits ruminants (PPR) is a highly contagious disease of small ruminants that leads to high morbidity and mortality thereby results in devastating economic consequences to the livestock industry. PPR is currently endemic across most parts of Asia and Africa, the two regions with the highest concentration of poor people in the world. Sheep and goats in particularly contribute significantly towards the upliftment of livelihood of the poor and marginal farmers in these regions. In this context, PPR directly affecting the viability of sheep and goat husbandry has emerged as a major hurdle in the development of these regions. The control of PPR in these regions could significantly contribute to poverty alleviation, therefore, the Office International des Epizooties (OIE) and Food and Agricultural Organization (FAO) have targeted the control and eradication of PPR by 2030 a priority. In order to achieve this goal, a potent, safe and efficacious live-attenuated PPR vaccine with long-lasting immunity is available for immunoprophylaxis. However, the live-attenuated PPR vaccine is thermolabile and needs maintenance of an effective cold chain to deliver into the field. In addition, the infected animals cannot be differentiated from vaccinated animals. To overcome these limitations, some recombinant vaccines have been developed. This review comprehensively describes about the latest developments in PPR vaccines.

Peste des petits ruminants

Peste des petits ruminants virus causes a highly infectious disease of small ruminants that is endemic across Africa, the Middle East and large regions of Asia. The virus is considered to be a major obstacle to the development of sustainable agriculture across the developing world and has recently been targeted by the World Organisation for Animal Health (OIE) and the Food and Agriculture Organisation (FAO) for eradication with the aim of global elimination of the disease by 2030. Fundamentally, the vaccines required to successfully achieve this goal are currently available, but the availability of novel vaccine preparations to also fulfill the requisite for differentiation between infected and vaccinated animals (DIVA) may reduce the time taken and the financial costs of serological surveillance in the later stages of any eradication campaign. Here, we overview what is currently known about the virus, with reference to its origin, updated global circulation, molecular evolution, diagnostic tools and vaccines currently available to combat the disease. Further, we comment on recent developments in our knowledge of various recombinant vaccines and on the potential for the development of novel multivalent vaccines for small ruminants.

Peste des petits ruminants vaccine and vaccination in India: sharing experience with disease endemic countries

Peste des petits ruminants, a viral disease of small ruminants, the control of which is important for poverty alleviation and to ensure livelihood security in Asia, Middle East and Africa. In recognition of these issues, we developed and applied vaccine and diagnostics to demonstrate effective control of PPR during preceding 6 years in a sub-population of small ruminants in India. Two south Indian states, namely Andhra Pradesh and Karnataka, strongly indicated possibility of PPR control with more than 90 % reduction in number of reported outbreaks of PPR, mostly through mass vaccination. Similarly, the situation at the national level also demonstrated a decline of more than 75 % in the number of reported outbreaks. Sharing these experiences may motivate other countries for similar initiatives leading to progressive control of PPR, which is in line with the initiatives of the organizations like FAO/OIE and the recent platforms on global PPR research alliance.

Peste des petits ruminants virus infection of small ruminants: a comprehensive review

Peste des petits ruminants (PPR) is caused by a Morbillivirus that belongs to the family Paramyxoviridae. PPR is an acute, highly contagious and fatal disease primarily affecting goats and sheep, whereas cattle undergo sub-clinical infection. With morbidity and mortality rates that can be as high as 90%, PPR is classified as an OIE (Office International des Epizooties)-listed disease. Considering the importance of sheep and goats in the livelihood of the poor and marginal farmers in Africa and South Asia, PPR is an important concern for food security and poverty alleviation. PPR virus (PPRV) and rinderpest virus (RPV) are closely related Morbilliviruses. Rinderpest has been globally eradicated by mass vaccination. Though a live attenuated vaccine is available against PPR for immunoprophylaxis, due to its instability in subtropical climate (thermo-sensitivity), unavailability of required doses and insufficient coverage (herd immunity), the disease control program has not been a great success. Further, emerging evidence of poor cross neutralization between vaccine strain and PPRV strains currently circulating in the field has raised concerns about the protective efficacy of the existing PPR vaccines. This review summarizes the recent advancement in PPRV replication, its pathogenesis, immune response to vaccine and disease control. Attempts have also been made to highlight the current trends in understanding the host susceptibility and resistance to PPR.

Diagnosis and control of peste des petits ruminants: a comprehensive review

Peste des petits ruminants (PPR) is an acute, highly contagious, world organization for animal health (OIE) notifiable and economically important transboundary viral disease of sheep and goats associated with high morbidity and mortality and caused by PPR virus. PPR is considered as one of the main constraints in augmenting the productivity of small ruminants in developing countries and particularly severely affects poor farmer's economy. The disease is clinically manifested by pyrexia, oculo-nasal discharges, necrotizing and erosive stomatitis, gastroenteritis, diarrhoea and bronchopneumonia. The disease can be diagnosed from its clinical signs, pathological lesions, and specific detection of virus antigen/antibodies/genome in the clinical samples by various serological tests and molecular assays. PPR is the one of the priority animal diseases whose control is considered important for poverty alleviation in enzootic countries. Availability of effective and safe live attenuated cell culture PPR vaccines and diagnostics have boosted the recently launched centrally sponsored control programme in India and also in other countries. This review article primarily focus on the current scenario of PPR diagnosis and its control programme with advancement of research areas that have taken place in the recent years with future perspectives.

Animal poxvirus vaccines: a comprehensive review

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

Seroprevalence and sero-conversion after vaccination against Peste des Petits Ruminants in sheep and goats from Awash Fentale District, Afar, Ethiopia

A cross-sectional epidemiological study followed by vaccination and postvaccinal serum antibody assessment against Peste des Petits Ruminants (PPR) in small ruminant population of Awash Fentale District, Afar, Ethiopia, was conducted from September 2006 to June 2007 with the aim of investigating seroprevalence and post-vaccination sero-conversion rate. A total of 1239 sera collected from sheep and goats which were not vaccinated, were screened by using nucleoprotein-based competitive enzyme-linked immunosorbent assay (c-ELISA). Only 21 (1.70%) animals were found to be positive. Following the base-line seroprevalence study, small ruminants in the area were vaccinated using the attenuated homologous PPR virus (Nigeria 75/1) strain vaccine, produced at National Veterinary Institute (NVI) in Debre-Zeit, Ethiopia. A total of 1096 small ruminants were resampled from the vaccinated population fourteen days after vaccination. The postvaccination sero-conversion rate in the population was found to be 61.13%, indicating a relatively weak herd immunity. The main reason for the low sero-conversion could be the thermolabile nature of the vaccine, since no statistically significant difference was observed between small ruminants vaccinated by Veterinary Professionals and Community Animal Health Workers (CAHWs), using Chi-squared test at 95% CI (P>0.05). This signifies the need for thermostable vaccine that could potentially increase the herd immunity in addition to that being administered by CAHWs independently. The current finding indicated that CAHWs could participate in vaccination campaigns in such areas as Afar, where there are few veterinarians despite of the huge livestock populations, as means of pastoralists' livelihood.

Comparative efficacy of live replicating sheeppox vaccine strains in Ovines

In the present study, two sheeppox vaccines made from strains [sheeppox virus-Srinagar (SPPV-Srin) and Ranipet (SPPV-R)] indigenous to India and adapted to Vero cells were compared in terms of their safety, potency, efficacy and antigenic value with the commercial in-use Roumanian Fanar (SPPV-RF) vaccine, a foreign strain adapted in primary lamb testes cells. The safety test indicated that the SPPV (Sri and RF) vaccines were safe while SPPV-R was not completely attenuated and caused excessive adverse reactions at the passage level tested. The immunized animals showed DTH reaction and resisted virulent SPPV challenge, while control animals developed disease. Specific virus could be detected in the controls and animals immunized with lower dilutions of vaccines after challenge but not in any of the sheep immunized with 1 and 100 doses of each vaccine. All vaccines were found potent and the PD(50) was highest for SPPV (Srin and R) followed by RF. The immunized animals were seroconverted following vaccination with sustained antibody responses after challenge. In conclusion, indigenous SPPV-Srin vaccine was found to be as efficacious as SPPV-R and SPPV-RF vaccines. Thus, there is potential benefit in replacing the currently used commercial vaccine SPPV-RF with indigenous SPPV-Srin vaccine for use in India.

Vaccines against peste des petits ruminants virus

Peste des petits ruminants (PPR) is a highly contagious and economically important viral disease affecting goats, sheep and wild ruminants. The disease is currently circulating in Asian and African countries, creating problems in small ruminant farming. Current control of the disease mainly includes isolation and disinfection of the contaminated environment, and administration of a live-attenuated vaccine, which provides a strong immunity. Maintenance of cold chain for vaccine efficacy has proven difficult in subtropical countries. A thermostable live-attenuated conventional or recombinant vaccine is a way to avoid cold chain-associated problems in tropical and subtropical countries. Mass vaccination of sheep and goats in endemic countries might be a pragmatic approach to control PPR in the first phase of disease eradication. In the future, the development of a marker vaccine with a robust companion test may help in serosurveillance to identify infection in vaccinated animals to control PPR disease. Here, we discuss available potent PPR vaccines and the future possibility of developing new-generation vaccines against PPR.