Prion Evolvability and the Hazard of Atypical Scrapie in Small Ruminants

2020 ◽  
Vol 1 (1) ◽  
pp. 1-14
Author(s):  
David B. Adams
Keyword(s):  
Disease Transmission ◽  
Western Europe ◽  
Current Knowledge ◽  
Small Ruminants ◽  
Classical Scrapie ◽  
Atypical Scrapie ◽  
Sheep And Goats ◽  
Preparedness Planning ◽  
Strain Behaviour ◽  
Third Stage

AbstractObservations on strain behaviour and direct demonstrations of natural selection establish that the scrapie agent and prions in general are able to evolve. Accordingly, it is conceivable that atypical non-contagious scrapie in sheep and goats can transform to classical contagious scrapie under particular circumstances. In consequence, atypical scrapie can be regarded as a latent hazard that warrants comprehensive risk assessment and biosecurity preparedness planning. Evidence for this proposition comes from differences in the expression of atypical and classical scrapie that may make scrapie contagious, historical records of scrapie in Western Europe, and contemporary accounts of the epidemiology of atypical scrapie. Biosecurity preparedness can be based on current knowledge of pathophysiology and epidemiology and can be built around a three-stage model for the endogenous emergence of a propagating epidemic of scrapie. The first stage concerns the occurrence of atypical scrapie. The second stage concerns the acquisition of communicability in prion populations provided by atypical scrapie and the third stage concerns circumstances allowing disease transmission and the initiation of a propagating epidemic. The range of component causes envisaged for possible outbreaks of endogenous classical scrapie is broad. However, exposure of sheep and goats to cyanobacterial toxins qualifies for special attention.

scholarly journals Reduction rate of nematode egg counts and third-stage larvae development from sheep and goat faeces preserved at 4οC

2018 ◽  
Vol 67 (3) ◽  
pp. 177 ◽  
Author(s):  
A. DRIMTZIA ◽  
E. PAPADOPOULOS
Keyword(s):  
Reduction Rate ◽  
Small Ruminants ◽  
Storage Period ◽  
Gastrointestinal Nematode ◽  
Sheep And Goats ◽  
Nematode Parasites ◽  
Faecal Samples ◽  
Third Stage ◽  
Faecal Egg Counts ◽  
Larvae Development

Gastrointestinal nematode parasites cause major production losses to small ruminants. The most common way to diagnose or monitor the worm burdens in sheep and goats remains the quantitative parasitological examinations, i.e. the faecal egg counts. However, the reliability of the results of such methods depends greatly on the conditions and duration of the storage of the faecal samples prior to examination. The aim of this research was to evaluate the reduction rate and the maximum storage period, without significant losses, of nematode egg counts and third-stage larvae development from sheep and goat faeces preserved at 4οC. Towards this end, a pooled faecal sample was formed by collecting faeces from naturally infected sheep and goats (separately). Faecal egg counts and coprocultures were performed on fresh faeces and on preserved ones every week and up to 119 days post sampling. It was concluded that the preservation at 4oC, i.e. into a refrigerator, of fresh faeces from sheep and goats for parasitological examinations poses danger of misdiagnosis, if not performed in a period not exceeding 3 weeks of time. The rate of reduction of the faecal nematode egg counts starts to be significant lower than the ones performed with fresh samples, for both sheep and goats, after the third week of storage. The percentage of the gastrointestinal nematode larvae developing to the infective third–stage alters significantly for the Haemonchus genus, soon after the first week of storage (p<0.05).

scholarly journals Novel Variations at Three Different Positions of Prion Protein Coding Gene in Ethiopian Sheep Breeds and the Resistance/Susceptible Status to Classical and Atypical Scrapie

2019 ◽  
Author(s):  
Eden Yitna Teferedegn ◽  
Yalcin Yaman ◽  
Cemal Un
Keyword(s):  
Prion Protein ◽  
Current Knowledge ◽  
Classical Scrapie ◽  
The Novel ◽  
Atypical Scrapie ◽  
Protein Coding ◽  
Essential Information ◽  
Sheep Population ◽  
Sheep Breeds ◽  
Scrapie Susceptibility

Abstract Background: Classical Scrapie susceptibility in sheep has been linked to three polymorphisms at positions 136, 154, and 171 in the PRNP gene whereas atypical scrapie susceptibility is related to a polymorphism at position 141. Many other variants over the length of the prion protein coding gene were reported. Since infectious prion protein itself seems to be polymorphic, the identified novel PRNP gene variations may play a crucial role in fighting against the emergence of a new form of scrapie disease. Many studies conducted around the world to identify disease resistant status and new variants of PRNP gene in different breeds. However, such in-depth studies have never addressed the African continent’s sheep breeds. Therefore, genotyping native Ethiopian sheep breeds PRNP gene provides essential information to the current knowledge. This study aimed to identify potential novel variations in the Ethiopian sheep PRNP gene, thereby determine the uniqueness of the native breeds and predict scrapie status of sheep population based on the genotypes distribution. Results : Five novel variants were identified in the PRNP gene of native Ethiopian sheep. Four non-synonymous heterozygous substitutions at H99Q (CAC-->CAA), H99L (CAC-->CTA), A116E (GCA-->GAA), A116T (GCA-->ACA), and one synonymous N103N (AAC-->AAT) variants were detected. In addition to the novel variations, polymorphisms at 126,127,138,142,146,231, and 237 positions were also identified. The haplotype ARR was observed only in Menz and Afar breeds with frequencies 0.02 and 0.05 respectively. However, neither ARR/ARR nor VRQ/VRQ genotypes were identified in all of the breeds. Conclusion: Two of the novel variations at position 99 and 103 that are placed closer to the cleavage site and variant at 116 spotted in the palindrome region along with variants at position 127 in Glycine repeat domain may influence the conformational flexibility of prion protein. The low frequency of ARR haplotype and the sole variant 141L demonstrated that Ethiopian sheep are susceptible to classical scrapie and resistant to atypical scrapie. This study provides a valuable dataset that can be potentially integrated into selective breeding strategies against scrapie during inbreeding, crossbreeding and help to take precautious measures.

scholarly journals Classical and Atypical Scrapie in Sheep and Goats. Review on the Etiology, Genetic Factors, Pathogenesis, Diagnosis, and Control Measures of Both Diseases

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 691
Author(s):  
Cristina Acín ◽  
Rosa Bolea ◽  
Marta Monzón ◽  
Eva Monleón ◽  
Bernardino Moreno ◽  
...  
Keyword(s):  
Prion Protein ◽  
Genetic Factors ◽  
Prion Diseases ◽  
Transmissible Spongiform Encephalopathy ◽  
Fatal Outcome ◽  
Small Ruminants ◽  
Cellular Prion Protein ◽  
Spongiform Encephalopathy ◽  
Atypical Scrapie ◽  
Sheep And Goats

Prion diseases, such as scrapie, are neurodegenerative diseases with a fatal outcome, caused by a conformational change of the cellular prion protein (PrPC), originating with the pathogenic form (PrPSc). Classical scrapie in small ruminants is the paradigm of prion diseases, as it was the first transmissible spongiform encephalopathy (TSE) described and is the most studied. It is necessary to understand the etiological properties, the relevance of the transmission pathways, the infectivity of the tissues, and how we can improve the detection of the prion protein to encourage detection of the disease. The aim of this review is to perform an overview of classical and atypical scrapie disease in sheep and goats, detailing those special issues of the disease, such as genetic factors, diagnostic procedures, and surveillance approaches carried out in the European Union with the objective of controlling the dissemination of scrapie disease.

scholarly journals Review: Update on Classical and Atypical Scrapie in Sheep and Goats

2018 ◽  
Vol 56 (1) ◽  
pp. 6-16 ◽  
Author(s):  
Justin J. Greenlee
Keyword(s):  
Prion Protein ◽  
Environmental Contamination ◽  
Protein Misfolding ◽  
Transmissible Spongiform Encephalopathy ◽  
Classical Scrapie ◽  
Spongiform Encephalopathy ◽  
Atypical Scrapie ◽  
Sheep And Goats ◽  
Scrapie Agent ◽  
Scrapie Strains

Scrapie is a naturally occurring transmissible spongiform encephalopathy (TSE) or prion disease of sheep and goats. Scrapie is a protein misfolding disease where the normal prion protein (PrPC) misfolds into a pathogenic form (PrPSc) that is highly resistant to enzymatic breakdown within the cell and accumulates, eventually leading to neurodegeneration. The amino acid sequence of the prion protein and tissue distribution of PrPSc within affected hosts have a major role in determining susceptibility to and potential environmental contamination with the scrapie agent. Many countries have genotype-based eradication programs that emphasize using rams that express arginine at codon 171 in the prion protein, which is associated with resistance to the classical scrapie agent. In classical scrapie, accumulation of PrPSc within lymphoid and other tissues facilitates environmental contamination and spread of the disease within flocks. A major distinction can be made between classical scrapie strains that are readily spread within populations of susceptible sheep and goats and atypical (Nor-98) scrapie that has unique molecular and phenotype characteristics and is thought to occur spontaneously in older sheep or goats. This review provides an overview of classical and atypical scrapie with consideration of potential transmission of classical scrapie to other mammalian hosts.

scholarly journals A Review of the Current Status of Peste des Petits Ruminants Epidemiology in Small Ruminants in Tanzania

2020 ◽  
Vol 7 ◽  
Author(s):  
Enokela S. Idoga ◽  
Bryony Armson ◽  
Ruth Alafiatayo ◽  
Adah Ogwuche ◽  
Erik Mijten ◽  
...  
Keyword(s):  
Vaccine Coverage ◽  
Current Knowledge ◽  
Close Contact ◽  
Vaccination Campaign ◽  
Clinical Signs ◽  
Small Ruminants ◽  
Current Status ◽  
Reference Laboratory ◽  
Peste Des Petits Ruminants ◽  
Sheep And Goats

Peste des petits ruminants (PPR) is a highly contagious viral disease of sheep and goats with high mortality. The disease is of considerable economic importance in countries such as Tanzania, where small ruminant products are important for sustainable livelihoods. This review assesses current knowledge regarding the epidemiology of PPRV in Tanzania, highlighting the challenges with respect to control and suggesting possible interventions. Thirty-three articles were identified after literature searches using Google Scholar and PubMed. Studies revealed that PPRV is endemic in sheep and goats in Tanzania, although seropositivity has also been reported in cattle, camels, buffalo, Grant's gazelle, wildebeest and impala, but with no clinical manifestation. Three lineages (lineage II to IV) of PPRV have been identified in Tanzania, implying at least two separate introductions of the virus. Diagnosis of PPR in Tanzania is mostly by observation of clinical signs and lesions at post mortem. Risk factors in Tanzania include age, sex, species, and close contact of animals from different farms/localities. Although there is an efficacious vaccine available for PPR, poor disease surveillance, low vaccine coverage, and uncontrolled animal movements have been the bane of control efforts for PPR in Tanzania. There is need for collaborative efforts to develop interventions to control and eradicate the disease. The establishment of a national reference laboratory for PPR, conduct of surveillance, the development of high-quality DIVA vaccines, as well as execution of a carefully planned national vaccination campaign may be key to the control and subsequent eradication of PPR in Tanzania and achieving the global goal of eradicating PPR by 2030.

scholarly journals Molecular Detection and Phylogeny of Anaplasmaphagocytophilum and Related Variants in Small Ruminants from Turkey

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 814
Author(s):  
Münir Aktaş ◽  
Sezayi Özübek ◽  
Mehmet Can Uluçeşme
Keyword(s):  
16S Rrna ◽  
Small Ruminants ◽  
Rrna Gene ◽  
Infection Rates ◽  
Sheep And Goats ◽  
Significant Difference ◽  
Pcr Rflp ◽  
First Time ◽  
Japan And China ◽  
Apparently Healthy

Anaplasma phagocytophilum causes tick-borne fever in small ruminants. Recently, novel Anaplasma variants related to A. phagocytophilum have been reported in ruminants from Tunisia, Italy, South Korea, Japan, and China. Based on 16S rRNA and groEL genes and sequencing, we screened the frequency of A. phagocytophilum and related variants in 433 apparently healthy small ruminants in Turkey. Anaplasma spp. overall infection rates were 27.9% (121/433 analyzed samples). The frequency of A. phagocytophilum and A. phagocytophilum-like 1 infections was 1.4% and 26.5%, respectively. No A. phagocytophilum-like 2 was detected in the tested animals. The prevalence of Anaplasma spp. was comparable in species, and no significant difference was detected between sheep and goats, whereas the prevalence significantly increased with tick infestation. Sequencing confirmed PCR-RFLP data and showed the presence of A. phagocytophilum and A. phagocytophilum-like-1 variant in the sampled animals. Phylogeny-based on 16S rRNA gene revealed the A. phagocytophilum-like 1 in a separate clade together with the previous isolates detected in small ruminants and ticks. In this work, A. phagocytophilum-like 1 has been detected for the first time in sheep and goats from Turkey. This finding revealed that the variant should be considered in the diagnosis of caprine and ovine anaplasmosis.

scholarly journals Innovation Meets Tradition in the Sheep and Goat Dairy Industry

Dairy ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 422-424
Author(s):  
Paola Scano ◽  
Pierluigi Caboni
Keyword(s):  
Dairy Industry ◽  
Small Ruminants ◽  
Farming Systems ◽  
Smallholder Farming ◽  
Sheep And Goats ◽  
Smallholder Farming Systems ◽  
The World

Small ruminants, such as sheep and goats, are mostly raised in smallholder farming systems widely distributed throughout the world [...]

scholarly journals Review of Peste des Petits Ruminants Occurrence and Spread in Tanzania

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1698
Author(s):  
Daniel Pius Mdetele ◽  
Erick Komba ◽  
Misago Dimson Seth ◽  
Gerald Misinzo ◽  
Richard Kock ◽  
...  
Keyword(s):  
Economic Impact ◽  
Disease Surveillance ◽  
Grey Literature ◽  
Small Ruminants ◽  
Peste Des Petits Ruminants ◽  
Serum Samples ◽  
Eradication Programme ◽  
Sheep And Goats ◽  
Ruminant Species ◽  
Socio Economic Impact

Peste des petits ruminants (PPR) is an important transboundary animal disease of domestic small ruminants, camels, and wild artiodactyls. The disease has significant socio-economic impact on communities that depend on livestock for their livelihood and is a threat to endangered susceptible wild species. The aim of this review was to describe the introduction of PPR to Tanzania and its subsequent spread to different parts of the country. On-line databases were searched for peer-reviewed and grey literature, formal and informal reports were obtained from Tanzanian Zonal Veterinary Investigation Centres and Laboratories, and Veterinary Officers involved with PPR surveillance were contacted. PPR virus (PPRV) was confirmed in northern Tanzania in 2008, although serological data from samples collected in the region in 1998 and 2004, and evidence that the virus was already circulating in Uganda in 2003, suggests that PPRV might have been present earlier than this. It is likely that the virus which became established in Tanzania was introduced from Kenya between 2006–7 through the cross-border movement of small ruminants for trade or grazing resources, and then spread to eastern, central, and southern Tanzania from 2008 to 2010 through movement of small ruminants by pastoralists and traders. There was no evidence of PPRV sero-conversion in wildlife based on sera collected up to 2012, suggesting that they did not play a vectoring or bridging role in the establishment of PPRV in Tanzania. PPRV lineages II, III and IV have been detected, indicating that there have been several virus introductions. PPRV is now considered to be endemic in sheep and goats in Tanzania, but there has been no evidence of PPR clinical disease in wildlife species in Tanzania, although serum samples collected in 2014 from several wild ruminant species were PPRV sero-positive. Similarly, no PPR disease has been observed in cattle and camels. In these atypical hosts, serological evidence indicates exposure to PPRV infection, most likely through spillover from infected sheep and goats. Some of the challenges for PPRV eradication in Tanzania include movements of small ruminants, including transboundary movements, and the capacity of veterinary services for disease surveillance and vaccination. Using wildlife and atypical domestic hosts for PPR surveillance is a useful indicator of endemism and the ongoing circulation of PPRV in livestock, especially during the implementation of vaccination to control or eliminate the disease in sheep and goats. PPR disease has a major socio-economic impact in Tanzania, which justifies the investment in a comprehensive PPRV eradication programme.

scholarly journals Determinants of Inlet Choices of Sheep and Goats Traders in Ghana: A Case Study of Kumasi and Tamale

2017 ◽  
Vol 9 (7) ◽  
pp. 105
Author(s):  
Fallah Samuel Kassoh ◽  
Jusufu Abdulai ◽  
Osman Nabay ◽  
Rebecca Bockarie
Keyword(s):  
Small Ruminants ◽  
Transportation Cost ◽  
Sampling Technique ◽  
Multinomial Logit Model ◽  
Sampling Frame ◽  
Fuel Price ◽  
Middle Income ◽  
Sheep And Goats ◽  
Multi Stage ◽  
Major Factors

The consumption of Small ruminants’ meat (sheep and goat) form an integral component of an average Ghanaian’s diet due to the country’s emergence to a middle income earning status and awareness of the outstanding benefits of a nutritious diet. However, periodic shocks in market availability of products severely impacts access and in most cases cause price hike hence affecting dietary patterns especially of urban dwellers that are mostly habitual in recurrent consumption of these products. Against such insight, this study investigates the factors that influence the inlet choice of sheep and goats traders in two urban towns of Ghana (Kumasi and Tamale) using Multinomial logit model. The selection of Kumasi and Tamale markets were based on the progressive marketing and consumption of sheep (S) and goats (G). A multi stage sampling technique was used in this study. A reconnaissance survey was carried out in Kumasi and Tamale metropolis in order to identify the existing markets and to generate the sample frame. Ten markets were purposively selected based on the proximity of the markets to the urban centres. A total of 284 traders were randomly sampled from the sampling frame. A structured questionnaire was used to collect relevant data, and analyzed using descriptive statistics and inferential statistics. The results of the study showed that majority of the traders were male with most (43%) falling within the age range of 31 to 40 years. International market (Burkina Faso) was identified as the major source of sheep and goats with 37% of total respondents sourcing from there. The major factors found to be influencing the inlet choice of sheep and goats by sampled traders in the study areas were prices, licenses, quantity of animals handled, transportation cost, education, experience and age of the traders. Based on the findings of the study, the following recommendations were suggested to improve the SG trade in urban centres of Ghana: Credit provision to traders who desire it to establish and expand their investment; reduction of license cost; and general reduction of fuel price so as to ease economic mobility of products.

scholarly journals Peste des petits ruminants in Africa: a review of currently available molecular epidemiological data, 2020

2020 ◽  
Vol 165 (10) ◽  
pp. 2147-2163 ◽  
Author(s):  
William G. Dundon ◽  
Adama Diallo ◽  
Giovanni Cattoli
Keyword(s):  
Economic Impact ◽  
International Organizations ◽  
Small Ruminants ◽  
Epidemiological Data ◽  
Viral Disease ◽  
Cash Income ◽  
Small Farmers ◽  
Peste Des Petits Ruminants ◽  
Sheep And Goats ◽  
Global Eradication

Abstract Small ruminants (e.g., sheep and goats) contribute considerably to the cash income and nutrition of small farmers in most countries in Africa and Asia. Their husbandry is threatened by the highly infectious transboundary viral disease peste des petits ruminants (PPR) caused by peste-des-petits-ruminants virus (PPRV). Given its social and economic impact, PPR is presently being targeted by international organizations for global eradication by 2030. Since its first description in Côte d’Ivoire in 1942, and particularly over the last 10 years, a large amount of molecular epidemiological data on the virus have been generated in Africa. This review aims to consolidate these data in order to have a clearer picture of the current PPR situation in Africa, which will, in turn, assist authorities in global eradication attempts.

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