Prevalence of peste des petits ruminants among sheep and goats in India

This study measured the clinical prevalence of peste des petits ruminants (PPR) among sheep and goats in India between 2003 and 2009 by analyzing clinical samples from suspected cases of PPR that were submitted to the Rinderpest and Allied Disease Laboratory, Division of Virology, IVRI, Mukteswar for PPR diagnosis. PPR outbreaks were confirmed by detecting PPR virus (PPRV)-specific antigen in the clinical samples. Clinical samples (blood, nasal swabs, spleen, lymph node, kidney, liver, intestine, and pooled tissue materials) were taken from a total of 592 sheep and 912 goats in different states of India and screened for the presence of PPRV antigen using a monoclonal antibody-based sandwich ELISA kit. A total of 20, 38, and 11 laboratory-confirmed PPR outbreaks occurred among sheep, goat, and combined sheep and goat populations, respectively. Our findings provide evidence of widespread PPR endemicity in India. The underlying reasons could be variations in husbandry practices in different geographical regions, agro-climatic conditions, and livestock migration. Furthermore, decrease in the number of PPR outbreaks over time might be due to the effectiveness of current live PPR vaccines and timely vaccination of target species. Vaccination against PPR has been practiced in India since 2002 to control this disease.     

“后牛瘟时代”的全球牛瘟研究

2011年，联合国粮食及农业组织(FAO)和世界动物卫生组织(WOAH)联合宣布根除牛瘟。这是历史上首个消灭的动物疫病，也是继天花之后全球第二个被消灭的传染病，自此，世界进入“后牛瘟时代”。牛瘟再暴发风险依然存在，维持全球牛瘟无疫状态意义重大。就维持全球牛瘟无疫状态的框架性文件、牛瘟病毒保藏机构以及宣布消灭牛瘟后所发表的实验性研究等进行了综述，为提升公众风险意识、应对牛瘟再暴发提供参考。     

The detection of antibody against peste des petits ruminants virus in Sheep,Goats, Cattle and Buffaloes

Monoclonal antibody-based competitive ELISA (C-ELISA) has been used for the specific measurement of antibodies to peste des petits ruminants (PPR) viruses in sheep, goats, cattle and Buffalo. Serum samples from sheep (n = 232), goats (n = 428), cattle (n = 43), buffalo (n = 89) were tested. The animals had not been vaccinated against rinderpest or PPR. Findings suggested that the sero-positive cases were significantly higher in sheep (51.29%) than in goats (39.02%) (P = 0.002). The overall sero-prevalence of PPRV in small ruminants was 43.33%. The PPR antibodies seroprevalence was 67.42% in buffalo and 41.86% in cattle which was significantly higher in buffalo (P = 0.005). The overall sero-prevalence of PPRV in large ruminants was 59.09%. Cattle and buffalo sera showed a high prevalence of antibody against PPR virus which may explain the difficulty experienced in achieving high post-vaccination immunity levels against rinderpest. Because antibodies against PPR virus are both cross-neutralizing and cross-protective against rinderpest virus, further vaccination in the presence of antibodies against PPR virus may be a waste of national resources. It was also suggested that antibodies to PPR virus could prevent an immune response to the rinderpest vaccine. This paper presents serological evidence for the transmission of PPR virus from sheep and goats to cattle and buffalo and highlights the need to include PPR serology in the sero-monitoring programme to give a better indication of national herd immunity of sheep and goats against PPR.     

Differentiation of peste des petits ruminants and rinderpest viruses by neutralisation indices using hyperimmune rinderpest antiserum

Summary Six field isolates believed to be rinderpest viruses and 2 known strains of peste des petits ruminants (PPR) viruses were titrated in the presence of normal rabbit serum and with hyperimmune rinderpest antiserum prepared in rabbits. The known PPR viruses had indices less than 10 whereas 4 of the suspect field isolates had indices greater than a hundred. Two suspect field isolates had indices less than 20; both were collected from small ruminant wild life and are probably PPR viruses.

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Diferenciacion De Peste De Los Pequenos Rumiantes Y Virus De Rinderpest Mediante Indices De Neutrilizacion Utilizando Antisueros Hiperinmunes De Rinderpest

Resumen Seis aislamientos de campo sospediosos de Rinderpest y dos cepas conocidas de Peste de los pequeños rumiantes (PPR) fueron titulados en titulados en presencia de suero normal de conejo y suero hiperimmune a Rinderpest, prepardo en conjo. Las cepas concidos de PPR dierond titulos menores de 10, mientras que 4 de los aislamientos sospechosos de Rinderpest dieron titulos mayores de 100. Los 2 aislamientos de campo restantes dieron titulos menores de 20. Ambos fueron aislados de pequenños ruminantes silvestras y probablemente sean virus de PPR.

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Differenciation Des Virus De La Peste Bovine Et De La Peste Des Petits Ruminants Par Les Indices De Neutralisation Utilisant Des Antiserums Hyperimmuns De La Peste Bovine

Résumé La titration de 6 isolats recuellis sur le terrain et considérés comme étant du virus de la peste bovine, et 2 souches connues du virus de la peste des petits ruminants (PPR) ont été titrés en présence de sérum normal de lapin et avec un antisérum hyperimmun de la peste bovine préparé sur lapins. Les virus identifiés PPR avaient des indices inférieurs à 10 alors que 4 des isolats suspects présentaient des indices supérieurs à 100. Deux isolats suspects avaient des indices inférieurs à 20 et tous deux provenaient de petits ruminants sauvages et sont probablement des virus de la PPR.

     

Production and Characterization of Monoclonal Antibodies to Peste des Petits Ruminants (PPR) Virus

Peste des petits ruminants (PPR) is an acute, febrile viral disease of small ruminants, caused by a virus of the genus Morbillivirus. PPR and rinderpest viruses are antigenically related and need to be differentiated serologically. In the present study, 23 mouse monoclonal antibodies were produced by polyethyleneglycol (PEG)-mediated fusion of sensitized lymphocytes and myeloma cells. Among these, two belong to the IgM class and the remaining 21 to various subclasses of IgG. The MAbs from the IgG class designated 4B6 and 4B11 neutralized PPR virus in vitro. In radioimmunoprecipitation assay, 10 MAbs recognized nucleoprotein, 4 recognized the matrix protein and one each haemagglutinin and phosphoprotein. The remaining 7 MAbs failed to precipitate any defined viral protein. The reactivity pattern of the monoclonal antibodies in indirect ELISA indicated a close antigenic relationship within three Indian PPR (lineage 4) virus isolates and also within two rinderpest vaccine strains. All PPR virus isolates could be distinguished from rinderpest vaccine viruses on the basis of the reactivity pattern of all MAbs and anti-N protein MAbs. A set of six monoclonal antibodies specific to PPR virus could also be identified from the panel. From the panel of MAbs available, two MAbs were selected for diagnostic applications, one each for the detection of antigens and antibodies to PPR virus.     

Rinderpest.

Rinderpest, also known as cattle plague, was for centuries the most dreaded bovine plague known and one that changed the course of history and still seriously compromises trade. It can lay waste not only to farming communities but the wildlife heritage of countries also is threatened because its broad host spectrum extends across cattle, Asian buffaloes, yaks, and many other artiodactyls, both domesticated and wild, including swine. This article provides a brief history of rinderpest before describing its clinical, pathologic, epidemiologic, and diagnostic features. In dealing with control, the prospects for total eradication are described in the context of the Global Rinderpest Eradication Programme, which is on target to achieve that goal by 2010--the first time that an animal disease will have been eradicated.     

Comparative efficacy of standard AGID and precipitinogen inhibition test with monoclonal antibodies based competitive ELISA for the serology of <Emphasis Type="Italic">Peste des Petits Ruminants</Emphasis> in sheep and goats

This project was conducted to investigate the comparative efficiency of competitive ELISA (cELISA), standard Agar Gel Immunodiffusion Test (AGID) and Precipitinogen Inhibition Test (PIT) for the diagnosis of Peste des Petits Ruminants (PPR) in Pakistan. To deal with this, serum samples from 198 sheep and 82 goats were collected from three different government livestock farms and all the samples were run simultaneously with the three serological tests. The samples found positive for PPR antibodies through cELISA, AGID and PIT were 96 (34.2%), 60 (21.4%) and 72 (25.7%), respectively. Kappa statistics were applied to evaluate the concordance between the laboratory-based test (cELISA) and field-based tests (AGID and PIT). Kappa statistics scores for cELISA versus AGID and PIT were 0.6343 (95% Confidence Interval CI 0.5231–0.7456) and 0.7134 (95% Confidence Interval CI 0.5987–0.8281), respectively, which indicate a “substantial” agreement between cELISA and AGID and “significant” agreement between cELISA and PIT. AGID and PIT revealed relative diagnostic sensitivities with cELISA of 59.3% and 69.7% and relative diagnostic specificities of 98.3% and 97.2%, respectively. The data suggested that for mass screening and control of PPR, these serological tests proved practical in the absence of cELISA since they have high relative diagnostic specificities and a satisfactory relative diagnostic sensitivities.     

A recent outbreak of rinderpest in East Africa

Rinderpest was brought under control in Kenya in 1976 but in April 1986 an outbreak of the disease occurred in cattle in Western Kenya, five kilometres from the Kenya-Uganda border. This was the first confirmed field outbreak of the disease in Kenya after a lull of over 10 years. Clinical disease was confined to unvaccinated zebu calves aged six to eight months from which rinderpest virus was isolated. High titres of antibodies to rinderpest virus were demonstrated in sera collected from sheep and goats that were grazing together with the affected cattle herds; there was, however, no evidence of clinical disease in these small ruminants and wildlife species in the affected area. The disease outbreak was rapidly stamped out by quarantine and vaccination.     

Control of Peste des Petits Ruminants and Poverty Alleviation?

Peste des petits ruminants (PPR) is a contagious and often fatal viral disease of sheep and goats and also wild small ruminants. The PPR virus is distinct from but closely related to rinderpest virus and both belong to the morbivillivirus genus within the family Paramyxoviridae. PPR is a contagious transboundary disease with a significant impact on rural poor farmers. Its control should therefore be considered in programs that aim at alleviating poverty in developing countries.     

Re-infection of wildlife populations with rinderpest virus on the periphery of the Somali ecosystem in East Africa

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.     

Comparison of a maedi-visna virus CA-TM fusion protein ELISA with other assays for detecting sheep infected with North American ovine lentivirus strains.

A maedi-visna virus CA-TM fusion protein ELISA (MVV ELISA) was evaluated for the detection of antibody in sheep infected with North American ovine lentivirus (OvLV). The results of the MVV ELISA were compared with other assays for OvLV antibody and with viral infection in an intensively studied group of 38 sheep with a high prevalence of OvLV infection and disease. The sensitivity, specificity, and concordance of assays for OvLV antibody (MVV ELISA, indirect ELISA, Western blot, and AGID), virus (virus isolation, PCR, antigen ELISA), and OvLV-induced disease in each animal were compared with OvLV infection status as defined by a positive result in two or more of the assays. Five sheep met the criteria for absence of OvLV infection. The sensitivity of the MVV ELISA in detecting OvLV infected sheep was 64%, whereas the sensitivity of the other three tests for antibody ranged from 85 to 94%. All the antibody assays were 100% specific in this group of animals. Of the assays for virus, the PCR test had the highest sensitivity and the best concordance with OvLV infection, but it also had the lowest specificity of any of the virus or antibody assays. Among the antibody tests, the concordance of the MVV ELISA compared most favorably with the AGID test for detecting OvLV-infected sheep. Analysis of serum samples from 28 lambs experimentally-infected with one of three North American strains of OvLV suggested that there were no significant strain differences detectable by antibody assay. Twenty virus-inoculated lambs were positive by both the MVV ELISA and the AGID test, five lambs were MVV ELISA negative and AGID test positive, and three lambs were MVV ELISA positive and AGID test negative. No pre-inoculation samples were positive by either assay. In a longitudinal study involving seven lambs, antibodies to OvLV were detected by AGID 3-5 weeks post-inoculation, but were not detected by MVV ELISA until 5-10 weeks post-inoculation. Among 128 naturally and experimentally-infected sheep that were seropositive in the AGID test, the overall sensitivity of the MVV ELISA was higher in the naturally infected sheep (84%) than in the experimentally infected sheep (69%). The data indicated that the MVV ELISA represents a less sensitive, but specific alternative for the detection of OvLV antibodies.     

A competitive ELISA using anti-N monoclonal antibodies for specific detection of rinderpest antibodies in cattle and small ruminants.

A competitive ELISA (C-ELISA) using monoclonal antibodies (mAbs) which bind to the nucleo-protein (NP) of rinderpest virus (RPV) for detection of RPV antibodies in cattle and small ruminant sera is described. Unlike virus neutralisation test (VNT), this test using mAb IVB2-4, can detect specific RPV antibodies without showing a cross-reaction with antibodies to peste-des-petits ruminants-virus (PPRV); by contrast, when mAb VE4-1 is used the test detects both RPV and PPRV antibodies, including low levels of antibodies that can be found in sera containing maternal antibodies. Although antibodies to the PPRV 75-1 strain are also detected with mAb 51-5-6, the test is suitable for assessing the immune status of cattle against the Rinderpest Old Kabete (RBOK) strain. The results from a panel of sera with a known status of vaccination provide evidence for a highly significant correlation between C-ELISA and VNT. This test may be a useful tool for a standardized and accurate determination of the immunity status of both cattle and small ruminants.     

The production of peste des petits ruminants hyperimmune sera in rabbits and their application in virus diagnosis

Hyperimmune sera were produced by serial inoculation of rabbits with Vero cell-adapted, sucrose gradient-purified Nigerian peste des petits ruminants virus (PPRV) isolate. Two antisera produced, neutralized the homologous PPRV but not the heterologous rinderpest Kabette "O" virus. The antisera gave strong precipitin lines with purified PPRV antigens and were used to detect PPRV and rinderpest virus antigens from ante-mortem secretions and post-mortem tissue homogenates from PPR and rinderpest virus infected goats and cattle by the agar gel precipitation tests (AGPT). The hyperimmune sera gave good titration curves with both purified Nigerian goat and the United Arab Emirate wildlife PPRV isolates in the indirect enzyme linked immunosorbent assay (ELISA). Results of indirect ELISA showed that although there were some cross reactions with the rinderpest, canine-distemper and measles viruses, at 1:100 dilution, the antisera would give a positive signal with only the homologous PPR virus.     

Outbreaks of rinderpest in wild and domestic animals in Nigeria

Rinderpest, although eradicated from Nigeria in 1974 after the JP15 campaign, was reintroduced into Sokoto state in 1980 and again into Borno state in 1983. The latter outbreak spread rapidly throughout Nigeria and severely reduced the cattle population. An estimated one million cattle were lost. An outbreak occurred at the Maiduguri zoo, in Borno state, in January 1983 and killed 15 elands and six sitatungas. In March 1983, rinderpest appeared in Yankari game reserve in adjoining Bauchi state and caused mortality in several species of wildlife. A total of 207 buffalo, 20 warthog, eight waterbuck and two bushbuck carcases were recovered. Rinderpest did not occur in wildlife in Nigeria after it was eradicated from cattle. In the Nigerian situation, the rinderpest appears to have been transmitted from cattle to wildlife. Vaccination of zoo animals and valuable animals in game reserves, preferably with a killed vaccine, and ring vaccination of livestock around game reserves can help to protect wildlife from rinderpest.     

Attenuation of a strain of rinderpest virus: potential homologous live vaccine

Peste des petits ruminants (PPR) is a highly contagious disease of small ruminants frequently associated with severe mortality in these hosts. In countries where it occurs, PPR represents an important constraint to the improved productivity of sheep and goats. Until now the only way to combat this plague has been the use of heterologous rinderpest vaccine; all attempts to develop a homologous vaccine have ended in failure. The present communication describes the attenuation of the Nigerian strain PPRV Nig 75/1 by serial passage in Vero cells. The avirulent virus obtained has the same characteristics as Plowright and Ferris' rinderpest vaccine. The virus is advanced as a potential homologous vaccine against PPR.     

Continuing presence of rinderpest virus as a threat in East Africa, 1983-1985

The re-emergence of rinderpest virus in East Africa in 1979 caused widespread outbreaks of disease and subclinical infection throughout the region until mid-1983. Subsequent massive emergency vaccination campaigns have been successful in eliminating clinical rinderpest from Tanzania and preventing its spread southwards. Unfortunately the virus is still endemic in north-eastern Uganda and has recently caused epidemic outbreaks with high mortality in cattle in that country. In Kenya, buffaloes (Syncerus caffer) in and around the Masai Mara game reserve have developed antibodies to rinderpest virus as recently as late 1984. Although there have been no outbreaks of clinical disease in Tanzania or Kenya from April 1983 to the end of 1985 this serological evidence plus the increasing incidence of clinical outbreaks in Uganda indicate that rinderpest virus still threatens East Africa. The substantial aid which has been provided to the region for rinderpest control must be maintained.     

Serological studies with peste des petits ruminants and rinderpest viruses in Nigeria

One hundred and ninety-five goat and 67 sheep sera collected from various parts of southern Nigeria were screened for neutralising antibodies to both the peste des petits ruminants (PPR) and rinderpest viruses. Neutralising antibodies against both viruses were found in the sheep and goat sera examined. Parallel titration of samples which neutralised both viruses indicated a primary infection with the PPR virus (PPRV). However, some samples which failed to neutralise PPRV neutralised the rinderpest virus (RV) indicating RV activity in sheep and goats in Nigeria. These findings are discussed in relation to the diagnosis of PPRV infection and the recent reappearance of bovine rinderpest in Nigeria.     

Rinderpest: the end of cattle plague

This paper describes the demise of rinderpest, focussing on the 20th Century and especially the period of the Global Rinderpest Eradication Programme, before proceeding to describe the process of accreditation of rinderpest freedom which is now virtually complete.     

A comparison of whole virus and recombinant transmembrane ELISA and immunodiffusion for detection of ovine lentivirus antibodies in Italian sheep flocks

Sera from two sheep experimentally infected with ovine lentivirus (OLV) and from 186 sheep selected from flocks with known high or low prevalence of infection or on the basis of virological or histopathological examination were simultaneously tested by whole virus (WV) ELISA, recombinant transmembrane (r-TM) ELISA and AGID assay. Antigens for both the WV ELISA and AGID were prepared from an Italian field isolate; recombinant antigen was derived from the N-terminal region of the transmembrane envelope protein of strain K1514. The WV ELISA detected the highest number of seropositives, followed by the r-TM ELISA and AGID test. The sensitivity and specificity of the r-TM ELISA relative to the WV ELISA were 0.66 and 0.95, respectively. Immunoblot analysis of 14 WV ELISA-positive and r-TM ELISA-negative sera showed that the major core protein was immunodominant on WV antigen. It is concluded that the r-TM ELISA was more sensitive than the AGID test but less sensitive that the WV ELISA, particularly for detecting antibodies in the early stages of infection.Abbreviations AGID agar gel immunodiffusion - bp base pair - ELISA enzyme-linked immunosorbent assay - FBS fetal bovine serum - IB immunoblot - kD kilodalton - OLV ovine lentivirus - MEM minimal essential medium - p.i. post-infection - r recombinant - SDS-PAGE sodium dodecyl sulphate-polyacrylamide gel electrophoresis - TM transmembrane - WV whole virus     

Seroprevalence of Peste des petits ruminants in cattle and buffaloes from Southern Peninsular India

This study describes seroprevalence of Peste des petits ruminants (PPR) in cattle and buffaloes carried out during the period 2009–2010 using the randomly collected serum samples from different parts of Southern peninsular India. The report presents the results of PPR virus (PPRV)—specific antibodies in situations where either the subclinical or inapparent or non-lethal infection was there in cattle and buffaloes. A total of 2,548 serum samples [cattle = 1,158, buffaloes = 1,001, sheep = 303 and goat = 86] were collected and screened for PPRV antibodies by using a PPR monoclonal antibody-based competitive ELISA kit. Analysis of 2,159 serum samples indicates an overall 4.58% prevalence of PPRV antibody in cattle and buffaloes. The presence of PPRV-specific antibodies demonstrates that cattle and buffaloes are exposed to PPR infection naturally, and the transmission mode may be direct or indirect. Further, it implies the importance of bovines as subclinical hosts for the virus besides widespread presence of the disease in sheep and goats in the country.