Prevalence and distribution of peste des petits ruminants virus infection in small ruminants

Space-time cluster analysis and maximum entropy modeling of Peste des petits ruminants (PPR) in Türkiye

Peste des petits ruminants (PPR) is an economically important highly serious transboundary disease that mainly occurs in small ruminants such as sheep and goats. The aim of this study was to identify the probability of risk and and space-time clusters of Peste des Petits Ruminants (PPR) in Türkiye. The occurrence of PPR in Türkiye from 2017 to 2019 was investigated in this study using spatial analysis based on geographic information system (GIS). Between these dates, it was determined that 337 outbreaks and 18,467 cases. The highest number of outbreaks were detected in the Central Anatolia region. It was determined that PPR is seen more intensely in sheep compared to goats in Türkiye. In this study, 34 environmental variables (19 bioclimatic, 12 precipitation, altitude and small livestock density variables) were used to explore the environmental influences on PPR outbreak by maximum entropy modeling (Maxent). The clusters of PPR in Türkiye were identified using the retrospective space-time scan data that were computed using the space-time permutation model. A PPR prediction model was created using data on PPR outbreaks combination with environmental variables. Nineteen significant (p < 0.001) space-time clusters were determined. It was discovered that the variables altitude, sheep density, precipitation in june, and average temperature in the warmest season made important contributions to the model and the PPR outbreak may be strongly related with these variables. In this study, PPR in Türkiye has been characterized significantly spatio-temporal and enviromental factors. In this context, the disease pattern and obtained these findings will contribute to policymakers in the prevention and control of the disease.

Seroprevalence and associated risk factors of peste des petits ruminants among ovine and caprine in selected districts of Afar region, Ethiopia

BACKGROUND

A Peste des petits ruminant is an acute, highly contagious and economically important transboundary viral disease of small ruminants. Despite the fact that food and agriculture organization and world organization for animal health plan to eradicate the disease by 2030, some studies indicated an increasing seropositivity of PPR infection in sheep and goats in Ethiopia. A cross-sectional study was employed to estimate the seroprevalence of PPR and to assess risk factors during the study period, February to April, 2020. Following purposive selection of the study districts, simple random sampling technique was employed to select individual animal during sample collection. A total of 384 serum samples were collected from apparently healthy sheep and goats. Competitive Enzyme Linked Immunosorbent Assay was used to detect the presence of antibodies against PPR at national veterinary institute. Descriptive statistics, Pearson's chi-square (X²) and logistic regression analysis were used is this study.

RESULTS

The overall animal level seroprevalence of PPR virus was found to be 60.15% (n = 231/384) and species level prevalence rate was found to be 38.18% (n = 42) in sheep and 68.98% (n = 189) in goats in the study areas. Among the associated risk factors considered; species, sex, age and herd sizes were significantly associated (P < 0.05) with the disease occurrence. Among the associated risk factors considered in this study, species, sex, age and herd size were found to be statistically associated with the seropositivity of PPR infection.

CONCLUSION

The present study finding revealed that a higher seroprevalence of PPR virus infection and this confirms peste des petits ruminant virus is circulating in Afar region. Further studies should be carried out on the entire region to determine PPR seroprevalence and to develop appropriate control and eradication strategies of PPR disease.

Peste des petits ruminants (PPR) in Africa and Asia: A systematic review and meta-analysis of the prevalence in sheep and goats between 1969 and 2018

BACKGROUND

Peste des petits ruminants (PPR) is a prevalent viral disease of sheep and goats that impacts productivity and international animal trade. Despite the substantial economic consequences related to PPR, little is known about the prevalence of this disease at the broad geographical levels.

OBJECTIVE

The present study aimed to use a systematic approach to assess the regional prevalence of PPR in sheep and goats, and the associated factors that contribute to prevalence estimates.

METHODS

Published articles on PPR in sheep and goats were searched in PubMed, Web of Science, Scopus, Google Scholar and the reference lists of articles reporting the prevalence from 1 January 1969 to 31 December 2018. Articles were selected using inclusion and exclusion criteria. Since the heterogeneity among the studies was significant, pooled prevalences were estimated by a random effect meta-analysis model.

RESULTS

Data on the prevalence of PPR were obtained from Africa and Asia, where the pooled prevalence estimates were 40.99% (95% CI: 37.20%-44.79%) and 38.43% (95% CI: 35.64%-41.22%) respectively. Overall, the estimated pooled prevalence at Africa-Asia level in sheep was 39.31% (95% CI: 35.75%-42.88%) and in goats was 39.57% (95% CI: 36.66%-42.48%). Significant heterogeneity (I²  > 80%) was noted in most pooled estimates.

CONCLUSION

The results on the regional prevalence estimates of PPR presented here will be useful in raising awareness and advocating for Governments to engage in initiatives to eradicate PPR and prevent it from spreading to other continents.

Peste des Petits Ruminants risk factors and space-time clusters in Mymensingh, Bangladesh

Using a hospital-based case-control study design, our aim was to identify risk factors for-and space-time clusters of-Peste des Petits Ruminants (PPR) in Mymensingh, Bangladesh. Three hundred and eighty PPR cases diagnosed between January 2005 and December 2014 at the Bangladesh Agricultural University Veterinary Teaching Hospital (BAUVTH) were selected; three controls per case from BAUVTH were then selected (n = 1,048). From records, data extracted included information on date of report, location, age, breed, sex and body weight of goats. A mixed multivariable logistic regression model was built to identify risk factors. Location was included as a random effect and season and demographic variables as fixed effects. The approximate geographic coordinates of locations were collected, and the scan statistic (Bernoulli model) was used to identify space-time clusters of PPR. Compared with goats <4 months of age, the odds of PPR were 3 (95% confidence interval [CI]: 1.95-4.66), 1.9 (CI: 1.34-2.76) and 1.8 times (95% CI: 1.19-2.58) greater in goats aged 4-6, >6-12 and >12-24 months, respectively. The occurrence of PPR was also significantly higher (odds ratio [OR] 3.2; 95% CI: 1.15-8.59) in the Jamunapari breed than Black Bengals. Significantly higher odds of PPR were observed in winter (OR 1.6; 95% CI: 1.06-2.14) and the monsoon season (OR 1.5; 95% CI: 1.04-2.11) compared with the post-monsoon season. Two significant (p < .05) space-time clusters were identified between 2 December 2006 and 6 September 2007 (two locations) and 28 November 2006 and 13 February 2007 (five locations). Peste des Petits Ruminants is endemic in Bangladesh, but also occurs as discrete outbreaks. Control efforts-such as vaccination-should focus on high-risk groups (4-24 months of age, Jamunapari breed), prior to the onset of winter and the monsoon season so as to increase immunity during high-risk periods, and focus on disease hotspots.

Peste des petits ruminants in Pakistan; past, present and future perspectives

Peste des petits ruminants (PPR) is considered to be one of the main constraints to enhancing the productivity of goats and sheep in regions where it is present and becoming endemic. PPR was recognized in Pakistan in early 1990s but got importance during the Participatory Disease Surveillance (PDS) of Rinderpest Eradication Campaign. Lot of research work has been initiated during last decade towards disease epidemiology, risk factor recognition, laboratory diagnosis, vaccination and demonstration of control strategies. Although there are ongoing projects working towards the progressive control of the disease in country yet there is need to have a national level control program for PPR. Also there is need to have comprehensive social economic surveys, disease hot spot recognition and identification of role of other species in disease transmission. With combined efforts of local and national authorities and political will, there is high likelihood that this devastating disease can be controlled and eventually eradicated in near future.

Seroprevalence, distribution and risk factor for peste des petits ruminants (PPR) in Algeria

Peste des petit ruminants (PPR) is a highly contagious and infectious viral disease of small ruminants with severe socio-economic implications. The disease was first reported in the Southern part of Algeria in 2011 and by February 2012 it has reached the central part of the country. Estimating national prevalence, distribution and identification of risk factors remains a key component in understanding the epidemiology and control of the disease. The present study was carried out between January and June 2014, to include a detailed description of flock and within-flock seroprevalence and risk association between PPR seropositivity and various flock management factors in Algeria. A total of 150 flocks randomly sampled across the country were investigated and 4552 serum samples were collected from 3336 sheep and 1216 goats, respectively. C-ELISA was used to detect the presence of antibodies in small ruminant animals as an indicator of PPRV exposure. The results showed an overall true flock seroprevalence of 30.45% [95% CI 23.76-37.14] with a mean of the true within-flock prevalence as 29.87%±2.11. The mean of the true within-flock prevalence in mixed flocks (12.93%±1.85) was however found to be significantly higher than sheep flocks (5.74%±1.06). Also the mean of the true within-flock prevalence was found to be significantly higher in adult (35.36%±3.13) compared to young animals (21.83%±2.47) and in females (33.11%±2.87) compared to males (22.14%±2.31). The univariate analysis revealed that PPR overall flock seroprevalence was significantly higher (P<0.20) in large flock (50.61%) than in small flock (33.33%), in mixed flock (56.7%) than in sheep flock (35.35%) and in the flocks that had contact with other flocks (46.5%) compared to those who had not (30.6%). However the differences among studied regions and grazing system were not statistically significant. For the risk factor analysis, univariate analysis of variables followed by a multiple logistic regression identified mixed flocks [OR=2.64, 95% CI 1.30-5.38; P=0.007] and contact with other flocks [OR=2.27, 95% CI 0.99-5.21; P=0.053] as risk factors in the spread of the disease. In conclusion, this study revealed a high seroprevalence of PPR in Algerian small ruminants, therefore the establishment of early warning systems and comprehensive implementation of control measures are advocated to improve animal welfare and reduce economic losses.

Small interfering RNAs targeting peste des petits ruminants virus M mRNA increase virus-mediated fusogenicity and inhibit viral replication in vitro

Peste des petits ruminants (PPR), caused by peste des petits ruminants virus (PPRV), is an acute or subacute, highly contagious and economically important disease of small ruminants. The PPRV is classified into the genus Morbillivirus in the family Paramyxoviridae. The PPRV matrix (M) protein possesses an intrinsic ability to bind to lipid membranes, and plays a crucial role in viral assembly and further budding. In this study, three different small interfering RNAs (siRNA) were designed on the basis of translated region for PPRV Nigeria 75/1M mRNA, and were subsequently synthesized for their transfection into Vero-SLAM cells, followed by infection with PPRVs. The results showed that two out of three siRNAs robustly induced cell-to-cell fusion as early as 36h post-infection with PPRVs, effectively suppressed expression of the M protein by interference for the M mRNA, and eventually inhibited viral replication in vitro. These findings led us to speculate that siRNA-mediated knockdown of the M protein would alter its interaction with viral glycoproteins, thus exacerbating intercellular fusion but hampering virus release.

Peste des petits ruminants outbreaks in White Nile State, Sudan

Eight outbreaks of peste des petits ruminants in sheep and goats were reported in White Nile State, Sudan, between 2008 and 2009. A mortality rate of 4.2% was reported across the different outbreaks. Clinically the disease was characterised by high fever, ocular and nasal discharge, pneumonia, ulceration of the mucous membranes, diarrhoea and death. The postmortem findings included necrotic lesions in the mouth and gastrointestinal tract, and swollen, oedematous lymph nodes associated with the lungs and intestine. Of the 209 serum samples tested by competitive enzyme-linked immunosorbent assay, 113 (54%) were found positive. Peste des petits ruminants virus was confirmed in tissues, nasal swabs and blood samples by immunocapture enzyme-linked immunosorbent assay, reverse-transcription polymerase chain reaction and isolation of the virus in culture of lamb testicle cells.

Peste des Petits Ruminants Viruses Re-emerging in China, 2013-2014

Re-emergence of peste des petits ruminants (PPR) was officially reported in Xinjiang Uygur Autonomous Region in north-western China in November 2013, and then along with the movements of goats and sheep, this disease rapidly spread to other provinces, autonomous regions and municipalities (P/A/M) of China. A total of 256 PPR-affected counties in 22 P/A/M were identified up to September 2014. Phylogenetic analysis revealed that the current circulating strains and Tibet strains isolated previously in 2007, both belonged to lineage IV but in different sub-branches. Nevertheless, compared with the Tibet strains, the current circulating strains shared high degree of genetic homology with those from Pakistan and Tajikistan.

Induction of protective immune response against both PPRV and FMDV by a novel recombinant PPRV expressing FMDV VP1

Peste des petits ruminants (PPR) and foot-and-mouth disease (FMD) are both highly contagious diseases of small domestic and wild ruminants caused by the PPR virus (PPRV) and the FMD virus (FMDV). In this study, a recombinant PPRV expressing the FMDV VP1 gene (rPPRV/VP1) was generated and FMDV VP1 expression did not impair replication of the recombinant virus in vitro and immunogenicity in inducing neutralizing antibody against PPR in goats. Vaccination with one dose of rPPRV/VP1 induced FMDV neutralizing antibody in goats and protected them from challenge with virulent FMDV. Our results suggest that the recombinant PPRV expressing the FMDV VP1 protein is a potential dual live vectored vaccine against PPRV and FMDV.

Rescue of recombinant peste des petits ruminants virus: creation of a GFP-expressing virus and application in rapid virus neutralization test

Peste des petits ruminants virus (PPRV) causes high mortality in goats and sheep and the disease has shown a greatly increased geographic distribution over the last 15 years. It is responsible for serious socioeconomic problems in some of the poorest developing countries. The ability to create recombinant PPRV would provide a useful tool for investigating the biology of the virus and the pathology of disease, as well as for developing new vaccines and diagnostic methods. Here we report the first successful rescue of recombinant PPRV from a full-length cDNA clone of the virus genome. Successful recovery of PPRV was achieved by using a RNA polymerase II promoter to drive transcription of the full-length virus antigenome. We have used this technique to construct a virus expressing a tracer protein (green fluorescent protein, GFP). The recombinant virus replicated as well as the parental virus and could stably express GFP during at least 10 passages. The newly established reverse genetics system for PPRV provides a novel method for constructing a vaccine using PPRV as a vector, and will also prove valuable for fundamental research on the biology of the virus. We found that our recombinant virus allowed more rapid and higher throughput assessment of PPRV neutralization antibody titer via the virus neutralization test (VNT) compared with the traditional method.

Sero-epidemiology of peste des petits ruminants (PPR) in Pakistan

A sero survey was conducted during 2005-2006 to estimate the sero prevalence of PPR in the small ruminant population of Pakistan. A total of 2798 samples were collected including goats (1979) and sheep (819) from villages in 27 randomly selected districts. These were tested by cELISA for PPRV and true prevalence estimates were calculated by Rogan and Gladen estimator. Overall, 1273 (45.5%) were found positive; 980 (49.5%) of 1979 samples from goats and 293 (35.8%) of 819 serum samples from sheep were positive. The true sero-prevalence of PPR was estimated to be 48.5% (95% CI, 46.6-50.3), and 52.9% (95% CI, 50.7-55.1) and 37.7 (95% CI, 34.4-41.0) for goats and sheep, respectively. PPR virus is widely distributed all across Pakistan and has become an endemic infection of small ruminants. Since it is one of the leading causes of morbidity and mortality in small ruminants, it poses a serious threat to food security and the rural economy in Pakistan.

Evidence of peste des petits ruminants in serology of sheep and goats from Sindh, Pakistan

The following is the first detailed description of laboratory confirmed evidence of peste des petits ruminant virus (PPRV) in 14 districts of Sindh province, Pakistan. Sindh is the 2nd largest province of Pakistan in terms of human population and livestock. Livestock are the main origin of the people's livelihood. Samples were collected during the surveillance programme from sheep and goats showing severe respiratory signs and mouth lesions. Competitive enzyme-linked immuno-sorbant assay (cELISA) was performed to detect the presence of antibodies in the serum against PPRV. Findings suggested that the overall PPR sero-prevalence in sheep was 49.5% when compared to goats, which was 56.3%. As we observed during an 18 months' period, most of the cases that occurred emerged with the start of hot season and peaked during the months of April, May, June and July, and then the prevalence dropped. Among various age groups, the animals that showed the higher prevalence of antibodies to PPRV were >2 years. In the age group <1 year, there was a significant difference in the prevalence which was 48.6% in goats when compared to 32.1% in sheep. Similarly, it was the same in the second age group (1-2 years), 46.9% in sheep when compared to 55.3% goats. There was little variation in the third age group (>2 years), being around 61.7% in goats when compared to 63.4% in sheep. The highest sero-prevalence was in Tharparkar followed by Mirpur Khas and Tando Allahyar. The study indicated the scenario of PPRV circulation in the population of the two domestic ruminant species (sheep and goats) with frequent disease outbreaks.