Les désignations et dénominations utilisées et la présentation des données figurant dans cet article ne reflètent aucune prise de position de l'OIEquant au statut légal de quelque pays, territoire, ville ou zone que ce soit, à leurs autorités, aux délimitations de leur territoire ou au tracé de leurs frontières.Les auteurs sont seuls responsables des opinions exprimées dans cet article.La mention de sociétés spécifiques ou de produits enregistrés par un fabricant, qu'ils soient ou non protégés par une marque, ne signifie pas que ceux-ci sont recommandés ou soutenus par l'OIE par rapport à d'autres similaires qui ne seraient pas mentionnés.
The African Union Panafrican Veterinary Vaccine Centre (AU–PANVAC) was strengthened as part of the second component of the VSPA project, in order to ensure the production and use of highquality PPR vaccines in Africa, in compliance with international standards.
The existence of peste des petits ruminants (PPR) in domestic ruminants and camels in Sudan during 2008–2012 was investigated. Lung tissues and serum samples were randomly collected from sheep, goats, cattle, and camels at different areas of Sudan. A total of 12,384 serum samples were collected from clinically healthy 7413 sheep, 1988 camels, 1501 cattle, 1459 goats, and 23 gazelles at different areas in the Sudan. They were examined for PPR antibodies using competitive ELISA (cELISA). The overall detected seroprevalence of PPR in tested sera was 49.4%; seroprevalence values within species were 67.1, 48.2, 25.8, 2.1, and 21.7% in sheep, goat, cattle, camels, and gazelles, respectively. The highest seroprevalence (68.1%) was observed in sera collected from Darfur states, then the central states (54.3%). A total of 1276 lung tissue samples (623 sheep, 324 cattle, 220 camels, and 109 goats) were collected. The majority of lung samples were collected from clinically healthy animals that showed lesions on PM in slaughterhouses (95%) and during PPR outbreaks; samples were tested for PPR antigen using immunocapture ELISA (IcELISA). PPR antigen was detected in 233 out of the 1276 tested samples (18.3%). Positive results were observed in samples collected from clinically healthy and diseased animals. The observed prevalence values in each species were 33.6, 21.1, 15.4, and 12.3% in camel, goat, sheep, and cattle, respectively. PPR antigen was detected in samples from different areas; however, the highest prevalence (63.9%) was found in samples collected from the eastern states, then Khartoum state (28%). Trials for virus isolation were done in different cell cultures. Out of 30 IcELISA-positive samples inoculated in primary bovine and ovine kidney cells, Vero cells, the PPR virus was successfully isolated from 15 (eight sheep, five camels, and two goats) samples in the three cell culture types. Using RT-PCR, PPRV nucleic acid was detected in all 25 IcELISA-positive tested samples.
Isolates of peste des petits ruminants virus (PPRV) can be segregated genetically into four lineages. For decades, lineages I-III have been reported across Africa whilst lineage IV has predominantly circulated across Asia. However, the lineage distribution is currently changing in Africa. Importantly, full genome sequence data for African field isolates have been lacking. Here, we announce the first complete genome sequence of a field isolate of peste des petits ruminants virus (PPRV) from East Africa. This isolate was derived from the intestine of a goat suffering from severe clinical disease during the 2010 outbreak in Ethiopia. The full genome sequence of this isolate, PPRV Ethiopia/2010, clusters genetically with other lineage IV isolates of PPRV, sharing high levels of sequence identity across the genome. Further, we have carried out a phylogenetic analysis of all of the available African partial N gene and F gene PPRV sequences to investigate the epidemiology of PPRV with a focus on the emergence of different lineages of PPRV in Africa.
Late October 2012, a great number of deaths of unknown origin occurred in goat herds in the suburbs of Ngazidja, located in the Comoros archipelago. Few weeks later, laboratory testing requested by the animal health authorities resulted in the identification of peste des petits ruminants (PPR) infection. Notably, the Index case could be attributed to a sick goat imported from Tanzania. Viral isolation was successful from the lungs leading to the whole N nucleoprotein gene sequencing. Phylogenetic analysis revealed that the strain belongs to the lineage III which includes strains of eastern African origin. In addition, to evaluate the impact of PPR on the Comorian indigenous domesticated ruminant population, a cross-sectional PPR serological survey was conducted between April and July 2013. A low overall PPRV antibody prevalence 2.24% (95% CI [1.38; 3.08]) was detected with a Grande Comore prevalence of 3.34% (IC = [2.09; 4.63]) with a limited spread of the disease mainly due to farm practices such as limited contacts between farm animals and rapid slaughtering of sick animals.
The Peste des petits ruminants (PPR) is a viral disease which affects sheep and goats and even the wild ruminants. About a billion small ruminants are found in the PPR enzootic areas. Morbilliviruses are primarily lymphotropic and secondarily epitheliotropic. Viral infection and interaction of viral proteins with lymphatic tissues are partly responsible for immune suppression. Transient immunosuppression is also observed after vaccination with attenuated vaccines. Viral isolation is traditionally done on Vero but newer recombinant cell lines are also used. In this work, sensitivity of three cell lines i.e. SLAM-ve-Vero, Vero.DogSLAMtag and B95a having Marmoset SLAM have been compared for PPRV titration. Moreover, infectivity of phytohemagglutinin (PHA) stimulated peripheral blood mononuclear cells (PBMCs) with PPR virus (PPRV) has been tested. Finally, live PPRV, recombinant nucleoprotein of PPR Virus (NPPRV) and truncated Delta 420-525 NPPRV have been used to demonstrate in vitro inhibition of PHA stimulated lymphoproliferation of PBMCs of naive goats. The presence of canine SLAM (Signaling lymphocyte activation molecule) receptor but not the marmoset SLAM, enhances infectivity of cell lines by up to 0.8 log(10). At multiplicity of infection (MOI) of 0.1, 83.6 percent of PBMCs can be infected with PPRV. PPRV could completely inhibit lymphoproliferation at MOI of 0.75 while NPPRV and Delta 420-525 NPPRV could suppress lymphoproliferation by 7.4 % and 17.6 %, respectively. PPRV is lymphotropic as PPRV (Nigeria 75/1) is capable of infecting mitogen activated PBMCs and that presence of canine SLAM in Vero cell line greatly enhances infectivity of PPRV as compared to SLAM negative Vero. Vero. DogSLAMtag is more sensitive cell line for PPRV titration and PPRV isolation. PPRV (Nigeria 75/1) and recombinant N-proteins induce in vitro inhibition of cell proliferation of mitogen stimulated PBMCs of naive goats. Using deleted mutant of NPPRV expressed in baculovirus system, amino acid sequence of NPPRV between 1-420 was found responsible for inducing immune suppression.
This study presents the results of a serological survey to assess the epidemiological status of peste des petits ruminants (PPR) in sheep and goats in different regions of Mali. The animals were tested by competitive ELISA (c-ELISA) to assess seroprevalence by region, species, age class and sex. Results showed an individual prevalence of 42.6% [confidence interval at 95% (CI95): 40.9 to 44.3]. Significant variations in seroprevalences were observed between regions and ranged from 5.5% (CI95: 3.3 to 7.7) in Gao (region with the lowest seroprevalence) to 55.6% (CI95: 52.2 to 59.1) in Koulikoro (region with the highest seroprevalence). Significant differences (p < 0.05) were observed between the estimated seroprevalences of females and males, and between adult (> 3 years) and younger animals (< 3 years), but not between sheep and goats. These results confirm the presence of the disease across the country with a relatively high prevalence in the central, southern and western regions. They also show the disease probably reached endemic levels, highlighting the low impact of the vaccination program against PPR in Mali. They reveal the urgent need to develop an effective vaccination program to protect livestock against this contagious disease.
IN the past 20 years, epizootics of Morbillivirus infection have occurred among several marine mammal populations worldwide ([Van Bressem and others 2001][1]). From 1990 to 1992, dolphin Morbillivirus spread to the striped dolphin ( Stenella coeruleoalba ) population of the Mediterranean sea,
Une analyse qualitative de risque a ete effectuee pour le risque d'introduction et de diffusion de la peste des petits ruminants (PPR) en France. Cette maladie virale contagieuse est actuellement presente en Afrique, au Moyen-Orient et en Asie. Une epizootie est survenue au Maroc en 2008. Les probabilites de chacun des evenements pouvant conduire a l'introduction du PPRV en France sont estimees qualitativement, ainsi que les consequences de l'apparition d'un eventuel foyer de PPR. Trois scenarios plus specifiquement a risque sont identifies et quelques points de vigilance pour la gestion de ce risque sont discutes. (Resume d'auteur)
The large (L) polymerase gene and the 5'-terminal UTR of the genome of peste des petits ruminants virus (PPRV), vaccine strain Nigeria 75/1, were cloned and sequenced. The L protein was also expressed in eukaryotic cells and its polymerase activity was quantitatively measured in a PPR reverse genetics assay using a reporter minigenome. Comparative sequence analysis of this functional L gene with corresponding genes of other morbilliviruses showed a degree of conservation exceeding 70%. The multiple sequence alignment and the phylogenetic study of L gene discriminated the morbilliviruses in 6 clusters, which are more closely related to Tupaia and Henipaviruses than to other paramyxoviruses. Important protein domains and functional motifs of the L polymerase of the PPRV Nigeria 75/1 vaccine were also identified by using different bioinformatics tools.
Rinderpest (RP) and peste des petits ruminants (PPR) are contagious viral diseases of domestic and wild ruminants producing high mortality. They are caused by viruses belonging to the Morbillivirus genus, Paramyxoviridae family. Control tools (vaccines and specific diagnostic tests) exist for these two diseases. They have been successfully used during the global rinderpest eradication programme (GREP) and the disease is expected to be eradicated by 2010. In contrast, a similar programme does not exist for PPR, which is still spreading in Africa and Asia. The persistence of PPR in Turkey and its recent introduction in Morocco, make the disease a real threat for Europe. Improvement of control measures against PPR would benefit from the development of a marker vaccine and its companion serological test, thus allowing the differentiation between infected and vaccinated animals (DIVA vaccines and tests). The recent development of reverse genetics for morbilliviruses offers this new possibility.
For Mononegavirales, the template for transcription and replication is not the naked RNA but the nucleoprotein (N) encapsidated genomic and anti-genomic RNA. Because of this central role in the replication of these viruses, N has been the subject of numerous structural and functional mapping studies. Here, we report on the cloning of the Peste des Petits Ruminants virus (PPRV) N gene into the baculovirus vector and the expression of the protein in insect cells. By electron microscopy observation, we have shown that this recombinant PPRV N forms nucleocapsid-like particles in insect cells in the absence of other PPRV proteins, as reported for other paramyxoviruses. As it is known that the formation of these particles is first linked to the self-assembly of N, we have made several deletions in the PPRV N gene and expressed these mutants in insect cells. Analysis of these proteins by immunoprecipitation and electron microscopy observation enabled us to map the N-N interaction domains into two regions of PPRV N: aa 1-120 and 146-241. The fragment aa 121-145, which is not conserved within the morbillivirus group, is also required for the formation/stability of the nucleocapsid helical structure.
In tropical countries the diagnosis of viral infections of humans or animals is often hampered by the lack of suitable clinical material and the necessity to maintain a cold chain for sample preservation up to the laboratory. This study describes the use of filter papers for rapid sample collection, and the molecular detection and genotyping of viruses when stored over long periods at elevated temperatures. Infected blood was collected on filter papers, dried and stored at different temperatures (22, 32 and 37 °C) for various periods (up to 9 months). Two animal viruses, African swine fever, a large double-stranded DNA virus and Peste des Petits Ruminants, a negative single-stranded RNA virus, were used to validate the method. Filter papers with dried blood containing virus or control plasmid DNA were cut in small 5 mm2 pieces and added directly to the PCR tube for conventional PCR. Nucleic acid from both viruses could still be detected after 3 months at 32 °C. Moreover, the DNA virus could be detected at least 9 months after conservation at 37 °C. PCR products obtained from the filter papers were sequenced and phylogenetic analysis carried out. The results were consistent with published sequences, demonstrating that this method can be used for virus genotyping.
By analysing the antigenic structure of the morbillivirus nucleoprotein (N) using a competitive-binding assay of monoclonal antibodies (mAbs), six different antigenic sites were identified previously. By using Pepscan methodology complemented by analysis of truncated N proteins, a better characterization of five of these antigenic sites was provided: I, II, III, IV and VI. mAbs specific to Rinderpest virus, defining antigenic sites II, III and IV, and those common to four morbilliviruses, delineating sites I and VI, were analysed in the present study. It was found that all but one mapped to the same region, between aa 120 and 149 of N. However, the mAb 3-1 epitope was located in the carboxy-terminal region (aa 421-525). This result may indicate the high immunogenicity of the amino-terminal variable region, at least in the mouse. It was surprising that the epitope of mAb 33-4, antigenic site VI, which recognized all morbilliviruses so far tested, was located in one of the two non-conserved regions between morbillivirus N proteins. It is shown that the conserved amino acid motif (126)EAD(128)----(131)F-------(148)EN(149) is critical for epitope constitution and recognition.
The occurrence of outbreaks of peste des petits ruminants (PPR) in three districts of Tajikistan is described. The causal strain (PPR Tajikistan) was characterized and the sequence of its N gene was compared with that of 43 other strains isolated since 1968 in Africa, the Middle East and Asia. The study demonstrated (1) the value of the N gene as a target in comparing isolates obtained over an extended period of evolution, and (2) that clustering was related to the geographical origin of strains.
We observed 15 goats for 9 days after subcutaneous infection with 10(3) TCID(50) with isolates of peste-des-petits ruminants virus from Africa and India and five concurrent, uninfected control goats. Typical clinical signs of the infection were present in all 15 infected goats by day 8 and in most by day 6 and some signs were present by day 4. However, 6 out of 15 goats already have detectable virus shedding by day 3 and four more were shedding by day 4 and every goat had virus shedding for at least 1 day before the recognition of clinical signs. This experiment indicates that incubatory carriers therefore might play a role in the transmission of PPRV among small ruminants.
We report surveillance for rinderpest virus in wildlife populations in three major ecosystems of East Africa: Great Rift Valley, Somali and Tsavo from 1994 to 2003. Three hundred and eighty wild animals were sampled for detection of rinderpest virus, antigen or genome and 1133 sampled for antibody in sera from Kenya, Uganda, Ethiopia and Tanzania from 20 species. This was done modifying for wildlife the internationally recommended standards for rinderpest investigation and diagnosis in livestock. The animals were selected according to susceptibility and preference given to gregarious species, and populations were selected according to abundance, availability and association with livestock. Rinderpest virus, antigen and/or genome were detected in Kenya; within Tsavo, Nairobi and Meru National Parks. Serological results from 864 animals (of which 65% were buffalo) from the region were selected as unequivocal; showing the temporal and spatial aspects of past epidemics. Recent infection has been only in or peripheral to the Somali ecosystem (in Kenya). Our evidence supports the hypothesis that wildlife is not important in the long-term maintenance of rinderpest and that wildlife are infected sporadically most likely from a cattle source, although this needs to be proven in the Somali ecosystem. Wildlife will continue to be a key to monitoring the remaining virus circulation in Africa.
Yellow fever (YF) is a mosquito-borne vaccine-preventable disease with high mortality. In West Africa, low population immunity increases the risk of epidemic transmission. A cluster survey was conducted to determine the effectiveness of a mass immunization campaign using 17D YF vaccine in internally displaced person (IDP) camps following a reported outbreak of YF in Liberia in February 2004. Administrative data of vaccination coverage were reviewed. A cluster sample size was determined among 17,384 shelters using an 80% vaccination coverage threshold. A questionnaire eliciting demographic information, household size, and vaccination status was distributed to randomly selected IDPs. Data were analyzed to compare vaccination coverage rates of administrative versus survey data. Among 87,000 persons estimated living in IDP camps, administrative data recorded 49,395 (57%) YF vaccinated persons. A total of 237 IDPs were surveyed. Of survey respondents, 215 (91.9%, 95% CI 88.4–95.4) reported being vaccinated during the campaign and 196 (83.5%, 95% CI 78.6–88.5) possessed a valid campaign vaccination card. The median number of IDPs living in a shelter was 4 (range, 1–8) and 69,536 persons overall were estimated to be living in IDP camps. Coverage rates from a rapid survey exceeded 90% by self-report and 80% by evidence of a vaccination card, indicating that the YF immunization campaign was effective. Survey results suggested that administrative data overestimated the camp population by at least 20%. An emergency, mop-up vaccination campaign was avoided. Coverage surveys can be vital in the evaluation of emergency vaccination campaigns by influencing both imminent and future immunization strategies.
A survey was carried out in two goat herds during a single peste des petits ruminant (PPR) outbreak. Clinical examination showed that animals belonging to the West African Dwarf species had severe symptoms while those belonging to the West African long-legged species had mild symptoms. To confirm and to monitor the disease in each species, the study required specific monoclonal antibody-based diagnostic tools. An association of shedding of PPR virus (PPRV) and acute or mild clinical signs of the disease could be demonstrated by the rinderpest virus (RPV)/PPRV immunocapture ELISA assay. Between 85 and 100 % of nasal secretions obtained from clinically diseased goats during the PPR outbreak reacted positively. Parallel serological surveillance for specific measurement of PPR antibodies revealed that between 34.4 and 88.5 % of animals with no detectable virus were, however, able to seroconvert and therefore seemed to demonstrate that PPR subclinical infections do occur. Antibodies were shown to impair the RP heterologous vaccination. This evaluation offers new prospects for diagnosis and management of PPRV infection as well as for RPV control.
ABSTRACTPeste des petits ruminants (PPR) is a contagious viral disease of small ruminants that is of economic importance in Africa, the Middle East, and Asia. We developed a rapid competitive enzyme-linked immunosorbent assay (rapid c-ELISA) for the diagnosis and surveillance of PPR. This assay detects PPR virus (PPRV) antibodies in serum samples by quantifying the amount of monoclonal antibody (MAb) P-3H12 after 30 min of incubation of a serum-MAb conjugate mixture on plates coated with a PPRV recombinant nucleocapsid protein (rPPRV-N). We tested 249 PPRV-positive serum samples and 733 PPRV-negative serum samples from field ruminants. The threshold of percent inhibition (PI) was determined to be <50 on the basis of the mean PI plus 3 standard deviations for sera from PPRV-negative ruminants. The relative specificity and sensitivity of the rapid c-ELISA were 98.5% (722 of 733 serum samples) and 93.4% (234 of 249 serum samples), respectively. The rapid c-ELISA sensitively detected PPRV antibodies in hyperimmune sera (virus neutralization test [VNT] titer, >512), even at dilutions ≥512 in normal goat serum, and as early as 6 to 13 days postinfection from 12 goats, each of which was infected with one of the four PPRV lineages. Hyperimmune sera from animals experimentally vaccinated with rinderpest virus gave positive results by the rapid c-ELISA when the rinderpest virus VNT titers were >512, although the rapid c-ELISA titers were very low (2 to 16). However, the rapid c-ELISA was negative when the rinderpest virus VNT titer was ≤128. The rapid c-ELISA developed in the present work provides a short turnaround time and could be a useful tool for the diagnosis of PPR and screening for PPRV in the field.