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

A Systematic Study of Bovine Viral Diarrhoea Virus Co-Infection with Other Pathogens

Bovine viral diarrhoea virus (BVDV) is the causative agent of bovine viral diarrhoea/mucocutaneous disease (BVD-MD). Its associated co-infections pose a threat to the cattle industry, which is becoming a key breakthrough in the global system of prevention in the cattle industry. In recent years, cases of co-infection have occurred and been reported from time to time, and this situation not only poses certain difficulties in controlling the outbreak and in treatment in the farming industry, but also poses considerable challenges in detection and diagnosis. In this review, by systematically integrating studies on BVDV co-infection, we firstly compared and analysed the characteristics of BVDV co-infection with viruses, bacteria and other pathogens in in vivo/in vitro models in terms of synergism, host immune response and epidemiological transmission. Then we systematically constructed a BVDV Co-infection Impact Map, which demonstrates a paradigm of pathogen-host-immune interactions in the transmission of BVDV and provides a theoretical framework for breaking through the current precision diagnostic strategies and showcasing the effectiveness of integrated prevention and control.

Unveiling of the Co-Infection of Peste des Petits Ruminants Virus and Caprine Enterovirus in Goat Herds with Severe Diarrhea in China

Here, we report the discovery of two viruses associated with a disease characterized by severe diarrhea on a large-scale goat farm in Jilin province. Electron Microscopy observations revealed two kinds of virus particles with the sizes of 150-210 nm and 20-30 nm, respectively. Detection of 276 fecal specimens from the diseased herds showed the extensive infection of peste des petits ruminants virus (63.77%, 176/276) and caprine enterovirus (76.81%, 212/276), with a co-infection rate of 57.97% (160/276). These results were partially validated with RT-PCR, where all five PPRV-positive and CEV-positive specimens yielded the expected size of fragments, respectively, while no fragments were amplified from PPRV-negative and CEV-negative specimens. Moreover, corresponding PPRV and CEV fragments were amplified in PPRV and CEV double-positive specimens. Histopathological examinations revealed severe microscopic lesions such as degeneration, necrosis, and detachment of epithelial cells in the bronchioles and intestine. An immunohistochemistry assay detected PPRV antigens in bronchioles, cartilage tissue, intestine, and lymph nodes. Simultaneously, caprine enterovirus antigens were detected in lung, kidney, and intestinal tissues from the goats infected by the peste des petits ruminants virus. These results demonstrated the co-infection of peste des petits ruminants virus with caprine enterovirus in goats, revealing the tissue tropism for these two viruses, thus laying a basis for the future diagnosis, prevention, and epidemiological survey for these two virus infections.

Serosurvey and Associated Risk Factors for Bovine Viral Diarrhea Virus Infection in Dromedary Camels in Egypt

Bovine viral diarrhea (BVD) is a disease that affects ruminants globally, including camels, and causing significant financial losses. The epidemiology of BVD in camels in Egypt are not well understood. Thus, this study aimed to determine the prevalence of anti-BVD virus (BVDV) antibodies in camels and identify the potential variables associated with the infection. A total of 400 camel sera from three Egyptian governorates were examined using commercial ELISA kit. The total seroprevalence was 4.8% in examined camels and the BVDV seropositivity were more prevalent in camels from Giza governorate. The highest seropositivity was found in aged camels more than 8 years (OR = 8.62, 95%CI: 1.03-71.87), camels from herd size less than 30 (OR = 4.20, 95%CI: 0.89-19.78), previously aborted animals (OR = 5.98, 95%CI: 2.12-16.92), and in animals kept in contact with sheep or goats (OR = 7.48, 95%CI: 2.56-21.86). Consequently, the camels may be a significant source of BVD infection for other ruminant animals in the same herd due to their susceptibility to the viral infection.

Expansion in host dynamics of peste des petits ruminants: Potential attribute of outbreaks in disease-endemic settings

Since the first case report in 1942, the peste-des-petits-ruminants virus (PPRV) has been causing infection in a wide range of susceptible hosts, particularly in disease-endemic regions. In the last 40 years, various reports highlighted the evidence of disease and viral genome in around 46 animal species from nine diverse families, including Bovidae, Cervidae, Camelidae, Suidae, Canidae, Felidae, Muridae, and Elephantidae. This evidence of clinical and/ or subclinical infection and the presence of the virus in an extended range of susceptible hosts emphasizes the cross-species transmission that remains a significant obstacle to effective control, particularly in disease-endemic regions. Therefore, a better understanding of virus transmission, host susceptibility, and epidemiological investigation of the disease is crucial to achieving the goals of efficient disease control and eradication programs initiated by OIE and FAO in various diseases-endemic regions. Nevertheless, the propensity of PPRV to inter- and intra-transmission may be a possible constraint in disease control strategies in terms of the new outbreak with the involvement of unusual or novel hosts. Considering this aspect, we tried to summarize the scattered data on PPR in available information about the susceptibility of a wide range of wildlife species, large ruminants, camels, and unusual hosts.

BVDV, BHV-1 and BLV antibodies in dromedary camels of Turkey kept without and with ruminants

Camels are the only animals bred to sustain the tradition of wrestling in Turkey and are reared within a limited set of geographic areas. Farmers of such animals may also be engaged in ruminant breeding. The current research was aimed at documenting bovine viral diarrhoea virus (BVDV), bovine herpesvirus-1 (BHV-1), and bovine leukaemia virus (BLV) infections in sera collected from dromedary camels in four different geographical regions of Turkey during the years 2019-2021. All samples were tested for BVDV, BHV-1 and BLV antibodies as well as BVDV antigen by ELISA. Antibodies against BVDV were found in 16.8% of the camel sera tested. However, none of the camels sampled were positive in terms of BHV-1 and BLV antibodies as well as BVDV antigen. The prevalence was observed higher in the herds in which ruminants were raised in addition to camels (OR = 4.583, 95% CI, 1.298-16.182), (p = 0.018), while the prevalence was observed lower in the herds in which only camels were raised. This study showed that BVDV infection was more prevalent than BHV-1 and BLV infections in Turkish dromedary camels. Herewith, the camels, being a susceptible species to numerous viral ruminant diseases, may also serve as an important source of BVDV infection for other ruminant animals in the same flock.

Detection of peste des petits ruminants virus in pneumonic lungs from clinically apparently healthy camels slaughtered at Tambul slaughterhouse, Central Sudan

The study investigated the presence and prevalence of peste des petits ruminants (PPR) viral antigens among camels in Tambul area, Gezira State, Central Sudan, regardless of its sex, age and breed, and their possible contribution in the epidemiology of the disease in the Sudan. Hundred pneumonic lung tissues were aseptically collected from clinically apparently healthy camels showed no signs of illness at ante‐mortem examination, from Tambul slaughterhouse, Tambul area, Gezira State, Central Sudan, between November and December 2018. Samples were collected based on presence of the pneumonic signs, at the tissue level, including congestion of the lungs, presence of abscesses, fragility, changes in colour and thickness of the tissue. In order to detect PPR viral antigen, haemagglutination (HA) test was employed on lung tissue homogenate, using chicken RBCs suspension, which gave a positive reaction in 17–19 min. PPRV antigen was detected in 98 of camel samples with an overall antigenic prevalence of 98%. Of note, the HA titres achievable ranged from 4 to 256 HA units (HAU) with mean titre of 14.4 HAU, whereas apparently most of the samples achieved HA titres of 8 HAU. The results demonstrated presence of PPR viral antigens associated with pneumonia in camels indicating exposure of these camels to PPRV and probably presence of subclinical infection. Infection of species other than small ruminants suggests the fact that camels are potential hosts for PPRV and might play a role (or not) in the epidemiology of the disease. Further studies are needed to demonstrate if camels are able to transmit PPRV for in‐contact small ruminants or other animal species.

Ruminant pestiviruses in North Africa

Ruminant pestiviruses are widely distributed worldwide, causing congenital disease and massive economic losses. Although ruminant production is an important economic sector in North Africa, the knowledge about pestiviruses is scarce. The present study aimed at assessing the presence of Pestivirus in cattle in Algeria, and to review the data available on ruminant pestiviruses in North Africa. A cross-sectional study was conducted on dairy farms from North-Western Algeria. Blood samples from 234 dairy cattle from 31 herds were collected. All sera were analysed for the presence of antibodies using a commercial iELISA. The presence of Pestivirus RNA was also assessed by using a Reverse Transcription-PCR, and PCR-positive samples were sequenced. Risk factors related to Pestivirus infection were also analysed. The review of the presence of ruminant pestiviruses in North Africa was performed using a systematic search and compilation methodology of the peer-reviewed literature available in order to identify gaps of knowledge for future research. The seroprevalence at population and farm levels obtained in the present study (59.9% and 93.5%, respectively) concur with data reported in neighbouring countries. Risk factors associated with Pestivirus infection in cattle were the presence of sheep in the herd and the animal category (cow vs heifer). Furthermore, we confirmed the presence of BVDV-1a in Algeria. The scarce data suggest an endemic epidemiological scenario of pestivirus in livestock. The lack of studies about the epidemiology and molecular variability of ruminant pestiviruses in livestock and wildlife in North Africa is of concern for animal health and wildlife conservation, and needs to be addressed.

Sentinel surveillance of selected veterinary and public health pathogens in camel population originating from Southern Punjab province, Pakistan

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Camels are susceptible to a wide range of infectious diseases with varying rate of morbidity and mortality.

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Blutongue, peste des petits ruminants and brucellosis are prevalent among camels in southern part of the Punjab provinvce, Pakistan.

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Genome corresponding to Brucella abortus and multiple serotypes of bluetongue were detected among camels.

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Camels should be included for disease control interventions reltaed to brucellosis, blutongue and PPR from their endemic setting worldwide.

An extended range of host susceptibility including camel has been evidenced for some of the important veterinary and public health pathogens, such as brucellosis, peste des petits ruminants (PPR) and bluetongue (BT). However, in disease endemic settings across many parts of the globe, most of the disease control interventions accounts for small and large ruminants, whereas unusual hosts and/or natural reservoirs, such as camels, remain neglected for disease control measures including routine vaccination. Such a policy drawback not only plays an important role in disease epizootiology particularly in settings where disease is endemic, but also serves an obstacle in disease control and subsequent eradication in future. With this background, using pre-validated ELISA and molecular assays [multiplex PCR, reverse transcriptase (RT)-PCR and real-time (rt)-PCR], we conducted a large-scale pathogen- and antibody-based surveillance for brucellosis, peste des petits ruminants and bluetongue in camel population (n = 992) originating from a wide geographical region in southern part of the Punjab province, Pakistan. Varying in each of the selected districts, the seroprevalence was found to be maximum for bluetongue [n = 697 (70.26%, 95% CI: 67.29–73.07)], followed by PPR [n = 193 (19.46%, 95% CI: 17.07–22.09)] and brucellosis [n = 66 (6.65%, 95% CI: 5.22–8.43)]. Odds of seroprevalence were more significantly associated with pregnancy status (non-pregnant, OR = 2.23, 95% CI: 1.86–5.63, p<0.01), farming system (mixed-animal, OR = 2.59, 95% CI: 1.56–4.29, p<0.01), breed (Desi, OR = 1.97, 95% CI: 1.28–4.03, p<0.01) and farmer education (illiterate, OR = 3.17, 95% CI: 1.45–6.93, p<0.01) for BTV, body condition (normal, OR = 3.54, 95% CI: 1.92–6.54, p<0.01) and breed (Desi, OR = 2.19, 95% CI: 1.09–4.40, p<0.01) for brucellosis, and feeding system for PPR (grazing, OR = 2.75, 95% CI: 1.79–4.22, p<0.01). Among the total herds included (n = 74), genome corresponding to BT virus (BTV) and brucellosis was detected in 14 (18.92%, 95 CI: 11.09–30.04) and 19 herds (25.68%, 95% CI: 16.54–37.38), respectively. None of the herds was detected with genome of PPR virus (PPRV). Among the positive herds, serotype 1, 8 and 11 were detected for BTV while all the herds were exclusively positive to B. abortus. Taken together, the study highlights the role of potential disease reservoirs in the persistence and transmission of selected diseases in their susceptible hosts and, therefore, urges necessary interventions (e.g., inclusion of camels for vaccine etc.) for the control of diseases from their endemic setting worldwide.

Peste des petits ruminants in large ruminants, camels and unusual hosts

Since its first report in 1942, peste-des-petits-ruminants virus (PPRV) has caused several epidemics in a wide range of susceptible hosts around the world. In the last 30 years, the evidence of natural and experimental infections and virus isolation were reported from novel but unusual hosts such as camel, cattle, buffalo, dogs, Asiatic lion and pigs. In addition, PPRV in a potential vector, biting midges (Culicoides imicola), has been reported. Either presented as clinical and/or subclinical infections, the presence of the virus in an extended range of susceptible hosts highlights the cross-species transmission and supports the hypothesis of an endemic circulation of PPRV among susceptible hosts. However, the potential role of large ruminants, camels and unusual hosts for PPRV epidemiology is still obscure. Therefore, there is a need for molecular and epidemiological investigations of the disease among usual and unusual hosts to achieve the goals of disease control and eradication programmes initiated by national and international organisations, such as the FAO and OIE. This review is the first to summarise the scattered data on PPR in large ruminants, camels and unusual hosts to obtain the global scientific communities' attention for further research on epidemiological aspects, not only in its native hosts, but also in large ruminants, camels and other unusual hosts.

Expanding Diversity of Susceptible Hosts in Peste Des Petits Ruminants Virus Infection and Its Potential Mechanism Beyond

Peste des petits ruminants (PPR) is a severe respiratory and digestive tract disease of domestic small ruminants caused by PPR virus (PPRV) of the genus Morbillivirus. Although the primary hosts of PPRV are goats and sheep, the host range of PPRV has been continuously expanding and reported to infect various animal hosts over the last decades, which could bring a potential challenge to effectively control and eradicate PPR globally. In this review, we focused on current knowledge about host expansion and interspecies infection of PPRV and discussed the potential mechanisms involved.

Camelids and Cattle Are Dead-End Hosts for Peste-des-Petits-Ruminants Virus

Peste-des-petits-ruminants virus (PPRV) causes a severe respiratory disease in small ruminants. The possible impact of different atypical host species in the spread and planed worldwide eradication of PPRV remains to be clarified. Recent transmission trials with the virulent PPRV lineage IV (LIV)-strain Kurdistan/2011 revealed that pigs and wild boar are possible sources of PPRV-infection. We therefore investigated the role of cattle, llamas, alpacas, and dromedary camels in transmission trials using the Kurdistan/2011 strain for intranasal infection and integrated a literature review for a proper evaluation of their host traits and role in PPRV-transmission. Cattle and camelids developed no clinical signs, no viremia, shed no or only low PPRV-RNA loads in swab samples and did not transmit any PPRV to the contact animals. The distribution of PPRV-RNA or antigen in lymphoid organs was similar in cattle and camelids although generally lower compared to suids and small ruminants. In the typical small ruminant hosts, the tissue tropism, pathogenesis and disease expression after PPRV-infection is associated with infection of immune and epithelial cells via SLAM and nectin-4 receptors, respectively. We therefore suggest a different pathogenesis in cattle and camelids and both as dead-end hosts for PPRV.

Experimental infection of dromedary camels with virulent virus of Peste des Petits Ruminants

Peste des Petits Ruminants Virus (PPRV) causes a severe contagious disease of sheep and goats and has spread extensively in last years through Asia and Africa. PPRV, known to infect exclusively small ruminants, has been recently reported in camels in Iran and Sudan. Reported clinical symptoms are similar to those observed in small ruminants, fatality rate still unknown. However most of the authors reported seropositive camels without clinical signs. Camel sensitivity to PPRV is still controversial and more investigation need to be performed. In this study, we tested camel susceptibility by an experimental infection using a virulent PPRV strain belonging to lineage IV. Young dromedary camels were infected intravenously and observed one month for clinical symptoms. Viraemia and virus secretion charge in swabs were evaluated by PCR. Seroconversion was assessed by ELISA and virus neutralisation test. Infected animals did not manifest any clinical symptoms of the disease and no virus was detected in secretions. Seroconversion was observed from day 14 post infection.

Identification of diverse viruses in upper respiratory samples in dromedary camels from United Arab Emirates

Camels are known carriers for many viral pathogens, including Middle East respiratory syndrome coronavirus (MERS-CoV). It is likely that there are additional, as yet unidentified viruses in camels with the potential to cause disease in humans. In this study, we performed metagenomic sequencing analysis on nasopharyngeal swab samples from 108 MERS-CoV-positive dromedary camels from a live animal market in Abu Dhabi, United Arab Emirates. We obtained a total of 846.72 million high-quality reads from these nasopharyngeal swab samples, of which 2.88 million (0.34%) were related to viral sequences while 512.63 million (60.5%) and 50.87 million (6%) matched bacterial and eukaryotic sequences, respectively. Among the viral reads, sequences related to mammalian viruses from 13 genera in 10 viral families were identified, including Coronaviridae, Nairoviridae, Paramyxoviridae, Parvoviridae, Polyomaviridae, Papillomaviridae, Astroviridae, Picornaviridae, Poxviridae, and Genomoviridae. Some viral sequences belong to known camel or human viruses and others are from potentially novel camel viruses with only limited sequence similarity to virus sequences in GenBank. A total of five potentially novel virus species or strains were identified. Co-infection of at least two recently identified camel coronaviruses was detected in 92.6% of the camels in the study. This study provides a comprehensive survey of viruses in the virome of upper respiratory samples in camels that have extensive contact with the human population.

Seroprevalence and risk factors for peste des petits ruminants and selected differential diagnosis in sheep and goats in Tanzania

Introduction: Livestock husbandry is critical for food security and poverty reduction in a low-income country like Tanzania. Infectious disease is one of the major constraints reducing the productivity in this sector. Peste des petits ruminants (PPR) is one of the most important diseases affecting small ruminants, but other infectious diseases may also be present.

Objective: The objective of this study was to determine the seroprevalence and risk factors for exposure to PPR, contagious caprine pleuropneumonia (CCPP), foot-and-mouth disease (FMD), bluetongue (BT), and bovine viral diarrhoea (BVD) in sheep and goats in Tanzania.

Methods: Serum samples were collected in 2014 and 2015, and analysed using enzyme-linked immunosorbent assays to detect antibodies to the five pathogens.

Results and discussion: This is the first description of seroprevalence of FMD and BT among small ruminants in Tanzania. Risk factor analysis identified sex (female) (OR for 2014: PPR: 2.49, CCPP: 3.11, FMD: 2.98, BT: 12.4, OR for 2015: PPR: 14.1, CCPP: 1.10, FMD: 2.67, BT: 1.90, BVD: 4.73) and increasing age (>2 years) (OR for 2014: PPR: 14.9, CCPP: 2.34, FMD: 7.52, BT: 126, OR for 2015: PPR: 8.13, CCPP: 1.11, FMD: 2.98, BT: 7.83, BVD: 4.74) as risk factors for exposure to these diseases.

Complexities in Isolation and Purification of Multiple Viruses from Mixed Viral Infections: Viral Interference, Persistence and Exclusion

Successful purification of multiple viruses from mixed infections remains a challenge. In this study, we investigated peste des petits ruminants virus (PPRV) and foot-and-mouth disease virus (FMDV) mixed infection in goats. Rather than in a single cell type, cytopathic effect (CPE) of the virus was observed in cocultured Vero/BHK-21 cells at 6^th blind passage (BP). PPRV, but not FMDV could be purified from the virus mixture by plaque assay. Viral RNA (mixture) transfection in BHK-21 cells produced FMDV but not PPRV virions, a strategy which we have successfully employed for the first time to eliminate the negative-stranded RNA virus from the virus mixture. FMDV phenotypes, such as replication competent but noncytolytic, cytolytic but defective in plaque formation and, cytolytic but defective in both plaque formation and standard FMDV genome were observed respectively, at passage level BP8, BP15 and BP19 and hence complicated virus isolation in the cell culture system. Mixed infection was not found to induce any significant antigenic and genetic diversity in both PPRV and FMDV. Further, we for the first time demonstrated the viral interference between PPRV and FMDV. Prior transfection of PPRV RNA, but not Newcastle disease virus (NDV) and rotavirus RNA resulted in reduced FMDV replication in BHK-21 cells suggesting that the PPRV RNA-induced interference was specifically directed against FMDV. On long-term coinfection of some acute pathogenic viruses (all possible combinations of PPRV, FMDV, NDV and buffalopox virus) in Vero cells, in most cases, one of the coinfecting viruses was excluded at passage level 5 suggesting that the long-term coinfection may modify viral persistence. To the best of our knowledge, this is the first documented evidence describing a natural mixed infection of FMDV and PPRV. The study not only provides simple and reliable methodologies for isolation and purification of two epidemiologically and economically important groups of viruses, but could also help in establishing better guidelines for trading animals that could transmit further infections and epidemics in disease free nations.

One-Step Multiplex RT-qPCR Assay for the Detection of Peste des petits ruminants virus, Capripoxvirus, Pasteurella multocida and Mycoplasma capricolum subspecies (ssp.) capripneumoniae

Respiratory infections, although showing common clinical symptoms like pneumonia, are caused by bacterial, viral or parasitic agents. These are often reported in sheep and goats populations and cause huge economic losses to the animal owners in developing countries. Detection of these diseases is routinely done using ELISA or microbiological methods which are being reinforced or replaced by molecular based detection methods including multiplex assays, where detection of different pathogens is carried out in a single reaction. In the present study, a one-step multiplex RT-qPCR assay was developed for simultaneous detection of Capripoxvirus (CaPV), Peste de petits ruminants virus (PPRV), Pasteurella multocida (PM) and Mycoplasma capricolum ssp. capripneumonia (Mccp) in pathological samples collected from small ruminants with respiratory disease symptoms. The test performed efficiently without any cross-amplification. The multiplex PCR efficiency was 98.31%, 95.48%, 102.77% and 91.46% whereas the singleplex efficiency was 93.43%, 98.82%, 102.55% and 92.0% for CaPV, PPRV, PM and Mccp, respectively. The correlation coefficient was greater than 0.99 for all the targets in both multiplex and singleplex. Based on cycle threshold values, intra and inter assay variability, ranged between the limits of 2%-4%, except for lower concentrations of Mccp. The detection limits at 95% confidence interval (CI) were 12, 163, 13 and 23 copies/reaction for CaPV, PPRV, PM and Mccp, respectively. The multiplex assay was able to detect CaPVs from all genotypes, PPRV from the four lineages, PM and Mccp without amplifying the other subspecies of mycoplasmas. The discriminating power of the assay was proven by accurate detection of the targeted pathogen (s) by screening 58 viral and bacterial isolates representing all four targeted pathogens. Furthermore, by screening 81 pathological samples collected from small ruminants showing respiratory disease symptoms, CaPV was detected in 17 samples, PPRV in 45, and PM in six samples. In addition, three samples showed a co-infection of PPRV and PM. Overall, the one-step multiplex RT-qPCR assay developed will be a valuable tool for rapid detection of individual and co-infections of the targeted pathogens with high specificity and sensitivity.

Mapping the evolutionary trajectories of morbilliviruses: what, where and whither

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Morbilliviruses are important human and animal pathogens.

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Measles virus is the prototype and is the most infectious human pathogen on earth.

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Live attenuated vaccines have been used to control the infections.

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Rinderpest virus is the second virus to be eradicated from earth.

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New morbilliviruses have been identified in cats and vampire bats.

Morbilliviruses are pathogens of humans and other animals. Live attenuated morbillivirus vaccines have been used to end endemic transmission of measles virus (MV) in many parts of the developed world and to eradicate rinderpest virus. Entry is mediated by two different receptors which govern virus lymphotropism and epitheliotropism. Morbillivirus transmissibility is unparalleled and MV represents the most infectious human pathogen on earth. Their evolutionary origins remain obscure and their potential for adaption to new hosts is poorly understood. It has been suggested that MV could be eradicated. Therefore it is imperative to dissect barriers which restrict cross species infections. This is important as ecological studies identify novel morbilliviruses in a vast number of small mammals and carnivorous predators.

Peste des Petits Ruminants Virus

Peste des petits ruminants virus (PPRV) causes a severe contagious disease of sheep and goats and has spread extensively through the developing world. Because of its disproportionately large impact on the livelihoods of low-income livestock keepers, and the availability of effective vaccines and good diagnostics, the virus is being targeted for global control and eventual eradication. In this review we examine the origin of the virus and its current distribution, and the factors that have led international organizations to conclude that it is eradicable. We also review recent progress in the molecular and cellular biology of the virus and consider areas where further research is required to support the efforts being made by national, regional, and international bodies to tackle this growing threat.