Improved PCR diagnostics using up-to-date in silico validation: An F-gene RT-qPCR assay for the detection of all four lineages of peste des petits ruminants virus.

Peste des petits ruminants (PPR) is a globally significant disease of small ruminants caused by the peste des petits ruminants virus (PPRV) that is considered for eradication by 2030 by the United Nations Food and Agriculture Organisation (FAO). Critical to the eradication of PPR are accurate diagnostic assays. RT-qPCR assays targeting the nucleocapsid gene of PPRV have been successfully used for the diagnosis of PPR. We describe the development of an RT-qPCR assay targeting an alternative region (the fusion (F) gene) based on the most up-to-date PPRV sequence data. In silico analysis of the F-gene RT-qPCR assay performed using PCRv software indicated 98% sensitivity and 100% specificity against all PPRV sequences published in Genbank. The assay indicated the greatest in silico sensitivity in comparison to other previously published and recommended PPRV RT-qPCR assays. We evaluated the assay using strains representative of all 4 lineages in addition to samples obtained from naturally and experimentally-infected animals. The F-gene RT-qPCR assay showed 100% diagnostic specificity and demonstrated a limit of detection of 10 PPRV genome copies per µl. This RT-qPCR assay can be used in isolation or in conjunction with other assays for confirmation of PPR and should support the global efforts for eradication.

Comparative evaluation of three capripoxvirus-vectored peste des petits ruminants vaccines.

Sheep and goat pox (SGP) with peste des petits ruminants (PPR) are transboundary viral diseases of small ruminants that cause huge economic losses. Recombinant vaccines that can protect from both infections have been reported as a promising solution for the future. SGP was used as a vector to express two structural proteins hemagglutinin or the fusion protein of PPRV. We compared immunity conferred by recombinant capripoxvirus vaccines expressing H or F or both HF. Safety and efficacy were evaluated in goats and sheep. Two vaccine doses were tested in sheep, 104.5TCDI50 in 1ml dose was retained for the further experiment. Results showed that the recombinant HF confers an earlier and stronger immunity against both SGP and PPR. This recombinant vaccine protect also against the disease in exposed and unexposed sheep. The potential Differentiating Infected from Vaccinated Animals of recombinant vaccines is of great advantage in any eradication program.

Confirmation and Sequence analysis of N gene of PPRV in South Xinjiang, China / Confirmação e análise de sequência do gene N de PPRV em Xinjiang do Sul, China

In China, Peste des petits ruminants (PPR) was officially first reported in 2007. From 2010 until the outbreak of 2013, PPRV infection was not reported. In November 2013, PPRV re-emerged in Xinjiang and rapidly spread to 22 P/A/M (provinces, autonomous regions and municipalities) of China. In the study, suspected PPRV-infected sheep in a breeding farm of South Xinjiang in 2014 were diagnosed and the characteristics of complete sequence of N protein gene of PPRV was analyzed. The sheep showed PPRV-infected signs, such as fever, orinasal secretions increase, dyspnea and diarrhea, with 60% of morbidity and 21.1% of fatality rate. The macroscopic lesions after autopsy and histopathological changes were observed under light microscope including stomatitis, broncho-interstitial pneumonia, catarrhal hemorrhagic enteritis and intracytoplasmic eosinophilic inclusions in multinucleated giantcell in lung. The formalin-fixed mixed tissues samples were positive by nucleic acid extraction and RT-PCR detection. The nucleotide of N protein gene of China/XJNJ/2014 strain was extremely high homology with the China/XJYL/2013 strain, and the highest with PRADESH_95 strain from India in exotic strains. Phylogenetic analysis based on complete sequence of N protein gene of PPRV showed that the China/XJNJ/2014 strain, other strain of 2013-2014 in this study and Tibetan strains all belonged to lineage Ⅳ, but the PPRV strains of 2013-2014 in this study and Tibetan strains were in different sub-branches.(AU)

Na China, Peste des petits ruminants (PPR) foi relatado oficialmente em 2007. De 2010 até o surto de 2013, não houve relato de infecção por PPRV. Em Novembro de 2013, PPRV ressurgiu em Xinjiang e rapidamente se espalhou para 22 P/A/M (províncias, regiões autônomas e municípios) da China. No estudo, ovelhas com suspeita de infecção por PPRV em uma fazenda de reprodução no sul de Xinjiang form diagnosticadas em 2014 e as características da sequência completa da proteína N do gene do PPRV foi analisada. As ovelhas tinham sinais de infecção pelo PPRV, como febre, aumento de secreções oro-nasais, dispneia e diarreia, com 60% de morbidade e 21.1% de fatalidade. As lesões macroscópicas após mudanças histopatológicas foram observadas sob microscópio, incluindo estomatite, pneumonia bronco-intersticial, enterite hemorrágica catarral e inclusões eosinofílicas intracitoplasmáticas em células gigantes multinucleares no pulmão. As amostras de tecido fixadas em formalina testaram positivo para detecção de RT-PCR por extração de ácido nucleico. Os nucleotídeos da proteína N do gene da linhagem China/XJNJ/2014 apresentou extrema homologia com o China/XJYL/2013, e homologia ainda maior com a variedade PRADESH-95 da Índia. Análise filogenética baseada na sequencia completa da proteína N do gene de PPRV mostrou que as variedades China/XJNJ/2014, outra de 2013-2014 mostrada nesse estudo e as Tibetanas todas pertenciam à linhagem Ⅳ, mas as PPRV de 2013-2014 nesse estudo e as Tibetanas estavam em diferentes agrupamentos.(AU)

Genetic Characterization of a Novel Mutant of Peste Des Petits Ruminants Virus Isolated from Capra ibex in China during 2015.

Peste des petits ruminants virus (PPRV) is the causative agent of peste des petits ruminants (PPR). The spread of PPR often causes severe economic losses. Therefore, special attention should be paid to the surveillance of PPR emergence, spread, and geographic distribution. Here we describe a novel mutant of PPRV China/XJBZ/2015 that was isolated from Capra ibex in Xinjiang province in China 2015. The sequence analysis and phylogenetic assessment indicate that China/XJBZ/2015 belongs to lineage IV, being closely related to China/XJYL/2013 strain. Interestingly, the V protein sequence of China/XJBZ/2015 showed lower homology with other Chinese PPRVs isolated during 2013 to 2014 (94%~95%), whereas it shared 100% identity with three Tibet strains isolated in China 2007. The 3' UTR, V gene, and C gene were determined to be highly variable. Besides, 29 PPR genomic sequences available in GenBank were analyzed in this study. It is the first time to use PPRV genomic sequences to classify the different lineages which confirmed the lineage clustering of PPRVs using N gene 255 bp fragments and F gene 322 bp fragments. In conclusion, our findings indicate that the PPRVs continue to evolve in China, and some new mutations have emerged.

Mixed infection of peste des petits ruminants virus (PPRV) and other respiratory viruses in dromedary camels in Sudan, an abattoir study.

This study was intended to determine the role played by peste des petits ruminants (PPR) in causing respiratory infections in camels and its association with other respiratory viruses. A total of 474 lung specimens showing pneumonia were collected from clinically healthy camels in slaughterhouses at five different areas in Sudan. Using immunocapture ELISA (IcELISA), 214 specimens (45.1 %) were found to be positive for PPR antigen. The highest prevalence was found in central Sudan (59.9 %) then northern Sudan (56.6 %) and eastern Sudan (26.6 %). Parainfluenza virus 3 (PIV 3), respiratory syncytial virus (RSV), bovine herpes virus-1 (BHV-1), bovine viral diarrhea (BVD), and adenovirus were detected in 4.4, 2.9, 2.0, 9.0, and 1.3 % of the specimens, respectively. PPR antigen was found in about 50 % of specimens that showed positive result for other viral antigens. Twenty-five of 28 BVD, 15 of 16 PIV3, 8 of 12 RSV, 4 of 4 adenovirus, and 4 of 5 BHV-1 were found in association with other respiratory antigens. Results revealed the existence of PPRV infection in dromedary camels in Sudan and present evidence for mixed virus infection, suggesting that respiratory infections in camels might be exacerbated by PPRV.

[Sequence analysis of the matrix protein and fusion protein genes of a field peste des petits ruminants virus strain from Tibet, China].

The nucleotide sequences of M and F genes from a field strain of peste des petits ruminants virus (PPRV) ("China/Tib/Gej/07-30") was firstly determined. The M gene was 1 483 nucleotides in length with a single open reading frame (ORF), encoding a protein of 335 amino acids. The F gene was 2411 nucleotides in length, encoding a protein of 546 amino acids. The resulting nucleotide sequence and the deduced amino acid sequences were compared with the homologous regions of other PPRV isolates. The nucleotide sequences of M and F genes of the "China/Tib/Gej/07-30" was 92.4%-97.7% and 85.5%-96.1% identical to other PPRV isolates, respectively, while a homology of 97.0%-98.2% and 94.3%-98.2% could be observed at the amino acids level respectively. Several sequence motifs in the M and F genes had been identified on the basis of conservation in the PPRVs and the morbilliviruses. The 3' untranslated region of M gene was 443 nucleotides in length with 82.4%-93.5% identical to other PPRV isolates. The 5' untranslated region of F gene was 634 nucleotides in length with 76.2%-91.7% identical to other PPRV isolates.

The M and N genes-based simplex and multiplex PCRs are better than the F or H gene-based simplex PCR for Peste-des-petits-ruminants virus.

Nucleocapsid (N), matrix (M) and hemagglutinin (H) genes-based simplex PCRs and an N and M genes-based multiplex PCR were developed for detection of Peste-des-petits-ruminants virus (PPRV). The M gene PCR was the most sensitive, followed by N, H and an already described fusion (F) gene PCRs, as they could detect the virus in samples with titers of 101, 102, 104and 105 TCID50/ml, respectively. The multiplex PCR was as sensitive as the M gene PCR, but it had the advantage of differentiating PPRV from Rinderpest virus (RPV).

Sequence analysis of the haemagglutinin and fusion protein genes of peste-des-petits ruminants vaccine virus of Indian origin.

The amino acid composition of the two surface proteins of peste-des-petits ruminants vaccine virus belonging to lineage four from India were deduced from the nucleotide sequence. The fusion (F) protein gene of PPRV Sungri/96 is 2405 nucleotides long and in relation to the length, it is 80 nucleotides longer than that of PPRV Nigeria/75/1 which are found to be present at the 5'UTR of this virus. The complete F gene alignment with other morbillivirus reveals a homology of 89% with PPRV/Nigeria/75/1 and 48-51% with other morbilliviruses. The F protein of PPRV Sungri/96 exhibited characteristics similarity to those of other morbillivirus F proteins. The overall amino acid similarity with its counterpart PPRV Nigeria/75/1 was 96%; with other morbilliviruses it is 65-74%. The PPRV Sungri/96 haemagglutinin (H) protein gene is 1954 nucleotides long and showed a sequence homology of 90.7% with PPRV/Nigeria/75/1 and with other morbilliviruses it ranged from 33% to 45%. At amino acids level, PPRV Sungri/96 showed a homology of 92.3% with PPRV/Nigeria/75/1 and 34-49% with other morbilliviruses. The phylogenetic tree constructed for F and H gene reveals four separate groups which is very similar to that found in other genes. To the best of our knowledge this is the first report describing the F and H genes of an Indian isolate.