| 1. |
- Fischer, Klara, et al.
(författare)
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Where is the Participation in Participatory Epidemiology? How Engagement with Social Science could lead to Improved Understanding and Control of Peste des Petits Ruminants.
- 2016
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Ingår i: British Journal of Virology. - : ResearchersLinks Ltd. - 2055-6128. ; 3, s. 105-114
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Forskningsöversikt (refereegranskat)abstract
- Peste des Petits ruminants (PPR) is a potentially lethal, highly contagious viral disease of sheep and goats. Domestic sheep and goats are important species for the livelihoods of poor people in many developing countries. Within societies where PPR is now spreading, poverty is widespread and the disease is expected to have significant negative impacts on livelihoods. In resource-constrained marginalised societies, it is often difficult to collect disease data in conventional ways. Participatory epidemiology (PE) has been suggested as a particularly suitable research method to study epidemiology and social impacts of diseases in these contexts. However, for PE to achieve its full potential, stronger efforts to achieve true participation and to incorporate lessons about participation and power from the social sciences may be required. This review shows that social science engagement in PE to date is virtually non-existent, but that increased efforts to draw lessons from the social sciences and to increase the degree of participation in PE could increase its potential as an important tool in disease impact assessment and control. Particular attention is paid here to the potential role of PE in future research on the epidemiology and control of PPR.
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| 4. |
- Johansson Wensman, Jonas, et al.
(författare)
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Epidemiological features of an outbreak of peste des petits ruminants depicting an endemic situation
- 2016
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Ingår i: British Journal of Virology. - : ResearchersLinks Ltd. - 2055-6128. ; 3, s. 123 - 129
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Tidskriftsartikel (refereegranskat)abstract
- An outbreak of Peste des Petits ruminants (PPR), possibly caused by the introduction of new animals in the herd, was investigated in an unvaccinated mixed herd of sheep and goats. Goats in the herd showed characteristic signs of PPR including nasal and ocular discharges, high temperature, diarrhea and ulcerative lesions in the oral cavity. A total of eighteen goats from a herd of sixty, were affected and two goats succumbed within two weeks. Interestingly, the disease was exclusively observed in goats and all sheep kept in the same herd were serologically positive but did not show any clinical signs of PPR. The active PPR virus (PPRV) infection was confirmed by antigen capture ELISA and RT-PCR in both swab and body tissue samples. The molecular characterization revealed clustering of the PPRV within lineage IV with significant substitutions in the nucleoprotein (NP) gene. Genetic variations within NP gene, and possibly in other proteins which are essentially mediating protective immunity, may explain the extreme infectious nature of the virus and its host-specific pathogenesis. Moreover, understanding the nature of such circulating field viruses is essential to underpin the endemic potential of PPRV and its possible spread to the susceptible wild or domestic small ruminants.
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| 6. |
- Kgotlele, Tebogo, et al.
(författare)
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Seroprevalence of peste des petits ruminants virus from samples collected in different regions of Tanzania in 2013 and 2015
- 2016
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Ingår i: Journal of Veterinary Science and Technology. - : OMICS Publishing Group. - 2157-7579. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Sero-surveillance was conducted to determine seroprevalence of peste des petits ruminant’s virus (PPRV) in sheep and goats population of Tanzania using samples collected in 2013 and 2015. A total of 3,838 samples were collected from villages in 14 of the 25 mainland regions. Samples were tested by competitive ELISA for detection of antibodies against PPRV. Overall, 998 of the samples were found to be positive for antibodies against PPR, giving a seroprevalence of 27.1%. In this study, there was no statistical significant difference of getting PPR between sheep and goats (odds ratio of 1.06, 95% CI 0.89-1.25). The overall seroprevalence indicates that PPR is prevalent in small ruminants in the study areas. The study also confirms the presence of antibodies against PPR in sheep and goats in regions of Tanzania that previously had little to no data on the disease, an indication that PPR is spreading within Tanzania with the possibility of spreading to neighboring countries.
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| 7. |
- Torsson, Emeli, et al.
(författare)
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Detection of peste des petits ruminants and concurrent secondary diseases in sheep and goats in Ngorongoro district, Tanzania
- 2019
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Ingår i: Comparative Clinical Pathology. - : Springer Science and Business Media LLC. - 1618-5641 .- 1618-565X. ; 28, s. 755-759
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Tidskriftsartikel (refereegranskat)abstract
- Small ruminants play an important role in the livelihoods of resource-constrained communities. This study was initiated because of a massive outbreak of a respiratory disease in sheep and goats in Loliondo area in Ngorongoro district of Arusha region in Tanzania in 2016. During flock examination, a total of 240 serum samples and 61 nasal swabs were collected. Antibodies to small ruminant morbillivirus, causative agent of peste des petits ruminants (PPR), were detected from sera using a competitive enzymelinked immunosorbent assay. A multiplex reverse transcription real-time polymerase chain reaction assay was used to detect four pathogens: small ruminant morbillivirus, Mycoplasma capricolum subspecies capripneumoniae, Pasteurella multocida, and Capripoxvirus from the nasal swabs. Overall seroprevalence of PPR was 74.6%, with all four pathogens detected from nasal swabs. Co-infections of small ruminant morbillivirus and Mycoplasma capricolum subspecies capripneumoniae, small ruminant morbillivirus and Capripoxvirus, small ruminant morbillivirus and Pasteurella multocida, and Mycoplasma capricolum subspecies capripneumoniae and Capripoxvirus were also detected. Presence of PPR and the other diseases in this study provided insight into the severity of the outbreak in sheep and goats in Ngorongoro district. Thus, laboratory confirmation is critical for prompt and appropriate interventions to be made for control of diseases in sheep and goats with similar clinical signs. The findings also call for research into development of combined vaccines targeting common diseases of small ruminants in Tanzania.
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| 9. |
- Torsson, Emeli, et al.
(författare)
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Field-Adapted Full Genome Sequencing of Peste-Des-Petits-Ruminants Virus Using Nanopore Sequencing
- 2020
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Ingår i: Frontiers in Veterinary Science. - : Frontiers Media SA. - 2297-1769. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Peste-des-petits-ruminants virus (PPRV) is currently the focus of a control and eradication program. Full genome sequencing has the opportunity to become a powerful tool in the eradication program by improving molecular epidemiology and the study of viral evolution. PPRV is prevalent in many resource-constrained areas, with long distances to laboratory facilities, which can lack the correct equipment for high-throughput sequencing. Here we present a protocol for near full or full genome sequencing of PPRV. The use of a portable miniPCR and MinION brings the laboratory to the field and in addition makes the production of a full genome possible within 24 h of sampling. The protocol has been successfully used on virus isolates from cell cultures and field isolates from tissue samples of naturally infected goats.
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| 10. |
- Torsson, Emeli, et al.
(författare)
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Filter paper is a simple and cost-effective transport medium for serological diagnosis of Peste des petits ruminants
- 2019
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Ingår i: Small Ruminant Research. - : Elsevier BV. - 0921-4488. ; 170, s. 154-159
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Tidskriftsartikel (refereegranskat)abstract
- Peste des petits ruminants (PPR) is a highly contagious disease caused by peste-des-petits-ruminants virus. Following the successful eradication of the related rinderpest virus, a program to control and eradicate PPR was launched by the FAO and OIE. PPR is today present in many tropical countries where maintaining the cold chain for sample transportation is one of the major barriers for timely processing. Transport of samples on filter paper is a simple and cost-effective method, however validation and optimization is required to fully adapt this approach. The objective of this study was to evaluate and validate the use of filter paper in serological diagnosis of PPR. Blood samples (serum and filter paper) were collected from sheep and goats in both Tanzania and Pakistan and analysed using a PPRV-specific cELISA. The positive proportion was 10.7% in Tanzania and 80% in Pakistan when performing the analysis on serum. These results were then considered as reference and compared to the results from the filter papers analysed by the same cELISA. According to the statistical analysis the cut-off for a positive results for samples stored on filter paper was adjusted from < 50 % competition percentage to < 84% in Tanzania and to < 69% in Pakistan.These results demonstrate that filter papers are an acceptable and cost-effective transport method of whole blood samples for later use in serological analysis.
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| 11. |
- Torsson, Emeli, et al.
(författare)
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History and current status of peste des petits ruminants virus in Tanzania
- 2016
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Ingår i: Infection Ecology & Epidemiology. - : Informa UK Limited. - 2000-8686. ; 6
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Forskningsöversikt (refereegranskat)abstract
- Peste des petits ruminants virus (PPRV) causes the acute, highly contagious disease peste des petits ruminants (PPR) that affects small domestic and wild ruminants. PPR is of importance in the small livestock-keeping industry in Tanzania, especially in rural areas as it is an important source of livelihood. Morbidity and case fatality rate can be as high as 80100% in naı¨ve herds; however, in endemic areas, morbidity and case fatality range between 10 and 100% where previous immunity, age, and species of infected animal determine severity of outcome. PPRwas officially confirmed in domestic animals in the Ngorongoro district of Tanzania in 2008. It is now considered to be endemic in the domestic sheep and goat populations throughout Tanzania, but restricted to one or more areas in the small ruminant wildlife population. In this article, we review the history and the current status of PPR in Tanzania and neighboring countries. To control and eradicate PPR in the region, a joint effort between these countries needs to be undertaken. The effort must also secure genuine engagement from the animal holders to succeed.
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| 12. |
- Torsson, Emeli
(författare)
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Peste des petits ruminants virus—in the field and in the host
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sheep and goats are one of the most important sources of food and income for many people around the world. They are especially important among vulnerable groups in Africa and Asia who may depend solely on them for their livelihood. The disease peste des petits ruminants (PPR) mainly affects domestic sheep and goats, and is caused by the highly contagious PPR virus (PPRV). PPRV is currently the goal of a control and eradication program launched by the Food and Agriculture Organ of the United Nations (FAO) and the World Organization for Animal Health (OIE). This thesis has explored aspects of PPR with the hope of helping the eradication effort. Among other things, the thesis has looked at prevalence and risk factors for PPRV, development of better diagnostic methods, and studied the virus-host interactions.The prevalence and risk factors for infection among sheep and goats in Tanzania was studied during two years. PPRV circulated with a prevalence of 49.3% in 2014 and 10.0% in 2015. The main risk factors for the animals were being female and increasing age. Interaction with wildlife was also evaluated as a risk factor, but did not lead to increased infection. The transport of serum samples was improved by validating the use of filter papers in a commercial cELISA. By adjusting the cut-off for a positive result, filter papers were a viable option for transport with unreliable cold-chains.Long transports are also a problem in molecular diagnosis, as the sensitive nucleic acid may degrade. A protocol was developed for a field-adapted full genome sequencing of PPRV. A portable miniPCR and a minION sequencing device, allow analysis at the disease outbreak or in a minimally equipped laboratory. A genetic marker of 255 nucleotides is commonly used for molecular epidemiology, but use of the full genome allows more precise tracing of the infection and viral evolution.A major symptom of PPR is a severe immunosuppression, mainly produced by the PPRV C and V proteins. The effects of these proteins were studied on the type I and II interferon (IFN) signaling pathways. The V protein was a strong inhibitor of both pathways, whereas the C protein inhibited the type I pathway, but stimulated the type II.
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