Sero-prevalence of peste des petits ruminants virus antibodies in sheep and goats from the Sudan, 2016-2017

Comparative study of HA and HNB staining RT-LAMP assays for peste des petits ruminants virus detection in West African Dwarf goats

Peste des petits ruminants (PPR) cause severe economic losses to many countries of the world where the disease is endemic. It has been targeted for global eradication by 2030 following the successful eradication of rinderpest in 2011. The proposed eradication program would benefit from efficient and relatively reliable diagnostic tools for early PPR virus (PPRV) detection. A total of 33 eight to 12 months old West African Dwarf (WAD) goats were used. Nineteen goats infected by commingling with two PPR virus-positive animals formed the infected group (PPRV-infected goats) while 14 non-infected goats formed the control group (CTG). The suitability of hydroxyl naphthol blue (HNB) staining of reverse transcription loop-mediated isothermal amplification (RT-LAMP) and haemagglutination (HA) assays was compared for their sensitivity to detect the PPRV in PPRV-infected goats and non-infected CTG. PPR disease severity in WAD goats at different days post infection (dpi) was evaluated by clinical scoring and haemagglutination titre (HAT). HNB staining RT-LAMP reaction and HA showed sensitivities of 100% and 73.68%, respectively, for PPRV detection. Expression of PPR clinical signs began from 3 dpi, attained peak at 5 dpi, thereafter showed irregular patterns till 24 dpi. Evaluation of HAT in PPRV-infected goats at 12 dpi ranged from 2 to 64 haemagglutination units (HAU), while CTG goats had 0 HAU. In conclusion, HA could be a good tool for rapid diagnosis of PPRV in a developing country setting. However, HNB staining RT-LAMP assay demonstrated high sensitivity for accurate diagnoses of PPRV and as an important diagnostic tool when precise phenotyping is desired.

Prevalence of peste des petits ruminants virus antibodies in sheep and goats sera from Central-Western Sudan

Clinical signs suggestive of peste des petits ruminants (PPR) involved herds of small ruminants, which were described elsewhere in Sudan. Peste des petits ruminants was confirmed using an Immunocapture ELISA (IC-ELISA) assay in samples of infected and dead animals in areas of outbreaks. Therefore, to update information regarding the current situation and for assessment of the serological prevalence of PPR in small ruminants mingled at Central and Western Sudan during 2018-2019, 368 sera were collected from sheep (325 sera) and goats (43 sera) with different ages and breeds. These sera included 186 sera (173 sheep and 13 goats) from White Nile State and 182 sera (152 sheep and 30 goats) from Kordofan States. Competitive ELISA demonstrated higher prevalence of PPRV antibodies of 88.9%, 90.7% and 88.6% in both sheep and goats, goats, and sheep sera, respectively. Moreover, 100%, 94.7% and 78.5% seroprevalence values were demonstrated in South Kordofan, North Kordofan and White Nile States. The higher seroprevalence values detected in sera of unvaccinated sheep and goats indicated the wide exposure of these animals to PPRV and presence of protection following PPR viral infection. The findings of the study indicated that PPR is endemic in the surveyed areas of Sudan.Contribution: The study will contribute effectively to the global eradication programme of PPR organised by the World Organization for Animal Health (WOAH, formerly OIE) and Food and Agriculture Organization (FAO). To completely eliminate PPR from Sudan by 2030, local efforts should be directed towards effectively and wholly vaccinating small ruminants using PPRV vaccine especially in routes of seasonal animal's movement and shared grazing areas.

Epidemiology and molecular characterization of re-emerged virulent strains of Peste des Petits Ruminants virus among sheep in Kassala State, Eastern Sudan

Background

Peste des Petits Ruminants (PPR) is a severe contagious viral disease, which mainly affects small ruminants. PPR is caused by a Morbillivirus that belongs to the family Paramyxoviridae. In this study 12 suspected PPR outbreaks among sheep and goats were investigated in four localities in Kassala State, Eastern Sudan, during 2015—2017. The causative agent was confirmed by a Sandwich Enzyme-Linked Immunosorbent Assay (sELISA), and a Reverse Transcription Polymerase Chain Reaction (RT-PCR) targeting a partial sequence of nucleocapsid protein gene (N- gene) and a partial sequence of fusion protein gene (F- gene). Sequencing and phylogenetic analysis were carried out on six N- gene based RT-PCR products selected from two outbreaks occurred on border and inner localities of Kassala State to determine the circulating lineages of PPRV strains. Identity percentages were determined between isolates in this study and previous Sudanese, and other (African and Asian) isolates which clustered along with them.

Results

Out of 30 samples, 22 (73.3%) were positive using sandwich ELISA. From 22 s ELISA positive samples, 17 (77.3%) were positive by Ngene based RT-PCR and only 7(43.8%) out of 16 positive samples by N gene based RT-PCR were positive using Fgene based RT-PCR. The sequencing and phylogenetic analysis confirmed involvement of the lineage IV of PPRV in outbreaks among small ruminants in Kassala State and high identity percentage between our isolates and previous Sudanese and other (African and Asian) isolates.

Conclusions

The present study demonstrates that genetic relationship between PPRV strains circulating in sheep in Kassala State, Eastern Sudan, and PPRV strains characterized as lineage IV in neighboring African countries such as Eretria,Ethiopia, Egypt, and other Asian countries

Detection of peste des petits ruminants virus in pneumonic lungs from apparently healthy sheep and goats slaughtered at Al-Hasaheisa slaughterhouse, Gezira state, central Sudan

The study aimed to investigate the presence of peste des petits ruminants (PPR) in pneumonic lung tissues from clinically apparently healthy sheep and goats and further demonstrating its prevalence in Gezira state, central Sudan. During March 2019, 99 pneumonic lung samples were collected from apparently healthy sheep (80) and goats (19) from Al-Hasaheisa slaughterhouse located in Al-Hasaheisa locality, Gezira state. Using the haemagglutination (HA) test for the detection of peste des petits ruminants virus (PPRV) antigen, an overall antigenic prevalence of 86.9% was demonstrated in sheep and goats lung tissue homogenate. Of note, the prevalence of PPRV is higher in goats (100%) compared to sheep (83.7%). In this study, the reported increasing prevalence of PPR in central Sudan might be because of insufficient vaccination of animals. The findings of the present study indicated the widespread of PPR amongst sheep and goats in Al-Hasaheisa, Gezira state. Detection of PPRV antigen in the pneumonic lung samples is an indication of exposure of these animals to PPRV or presence of PPR viral infection and demonstrates the role of PPR as the cause of pneumonia in small ruminants. In fact, the circulation of the virus in clinically apparently healthy animals poses a threat for other in-contact susceptible animals and could play a significant role in the spread of the 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.