RESUMO
In goats, several field studies have identified coding mutations of the gene encoding the prion protein (I/M142, N/D146, S/D146, R/Q211, and Q/K222) that are associated with a lower risk of developing classical scrapie. However, the data related to the levels of resistance to transmissible spongiform encephalopathies (TSEs) of these different PRNP gene mutations are still considered insufficient for developing large-scale genetic selection against scrapie in this species. In this study, we inoculated wild-type (WT) PRNP (I142R154R211Q222) goats and homozygous and/or heterozygous I/M142, R/H154, R/Q211, and Q/K222 goats with a goat natural scrapie isolate by either the oral or the intracerebral (i.c.) route. Our results indicate that the I/M142 PRNP polymorphism does not provide substantial resistance to scrapie infection following intracerebral or oral inoculation. They also demonstrate that H154, Q211, and K222 PRNP allele carriers are all resistant to scrapie infection following oral exposure. However, in comparison to WT animals, the H154 and Q211 allele carriers displayed only moderate increases in the incubation period following i.c. challenge. After i.c. challenge, heterozygous K222 and a small proportion of homozygous K222 goats also developed the disease, but with incubation periods that were 4 to 5 times longer than those in WT animals. These results support the contention that the K222 goat prion protein variant provides a strong but not absolutely protective effect against classical scrapie.
Assuntos
Predisposição Genética para Doença , Doenças das Cabras/genética , Scrapie/genética , Alelos , Animais , Códon , Feminino , Genótipo , Doenças das Cabras/metabolismo , Doenças das Cabras/patologia , Cabras/genética , Proteínas PrPSc/genética , Proteínas PrPSc/metabolismo , Distribuição TecidualRESUMO
The PrP gene polymorphisms at codons 142 (I/M), 154 (R/H), 211 (R/Q), 222 (Q/K) and 240 (S/P) and their association with susceptibility to classical scrapie infection were investigated in five French goat herds displaying a high disease prevalence (>10%). On the basis of PrP(Sc) detection in the central nervous system and in various lymphoid tissues, 301 of 1343 goats were found to be scrapie infected. The statistical analyses indicated that while P(240) mutation had no direct impact on scrapie infection risk, the H(154), Q(211) and K(222) mutations were associated with high resistance to scrapie. The M(142) mutated allele was associated with a limited protection level against the disease. These results further reinforce the view that, like in sheep, the control and eradication of classical scrapie through the selection of certain PrP alleles could be envisaged in commercial goat population.
Assuntos
Doenças das Cabras/genética , Príons/genética , Scrapie/genética , Alelos , Animais , Sistema Nervoso Central/imunologia , Sistema Nervoso Central/metabolismo , França/epidemiologia , Predisposição Genética para Doença , Doenças das Cabras/epidemiologia , Doenças das Cabras/imunologia , Cabras , Tecido Linfoide/imunologia , Tecido Linfoide/metabolismo , Mutação , Polimorfismo Genético , Prevalência , Scrapie/epidemiologia , Scrapie/imunologiaRESUMO
To be useful for operational programs, measures of resilience must not just be valid, but be easy to use and useful. Unfortunately, while resilience measurement techniques have progressed tremendously over the past decade, most progress has been on improving validity rather than utility and ease of use. In this article we present a new tool for measuring community resilience that incorporates issues of utility and ease of use, the Analysis of Resilience of Communities to Disasters (ARC-D) toolkit. The toolkit was developed over the course of ten years by the international humanitarian and development organization GOAL to enable aid organizations to measure community resilience in a way that supports resilience building interventions. It offers an approach to measurement that is cognizant of the resilience policy landscape, including the Sendai Framework, approaches to data collection and measurement uses relevant to aid agencies. We first present the core tenants of community resilience measurement before describing the toolkit, which consists of 30 measures, a guidebook, and an online platform. To illustrate its use, we a case study of a resilience building program in Tegucigalpa, Honduras. By developing one of the first resilience toolkits focused beyond validity and providing a description of how such an assessment works, this article has implications for resilience researchers and practitioners.
RESUMO
Within the framework of the national voluntary eradication program for Bovine alphaherpesvirus 1 (BoHV1) in France, the proportion of certified-free herds which experienced no more than two positive animals (termed singleton reactors) steadily increased to reach up to 95% in 2015. The aim of this study was to collate and evaluate serological data to gain insight into these epidemiological questionable BoHV1 seropositive animals. Preliminary evaluation of the performances of BoHV1 ELISA kits using a collection of 997 field sera with well-defined status revealed a relatively low specificity of the two gB blocking ELISAs most used in France for confirmatory testing (93.2% and 97.5% for gB-IDVet and gB-Idexx, respectively). In both ELISAs, the suboptimal specificity was associated with the presence of antibodies against BoHV2. Reassessment of the cut-offs led to a specificity and a sensitivity higher than 99.3%. Consequently, a comprehensive analysis of gB-positive sera from 2551 singleton reactors was performed by using gB ELISAs with optimized cut-offs, combined with viral neutralization test (campaign 2014-2015) or gE ELISA (campaign 2015-2016). Fifty percent of the 728 sera collected in 2014-2015 reacted below the optimized cut-offs in both gB ELISAs. Analysis of new blood samples collected at a minimum 6-week interval showed that these weak-positive reactions did not increase with time and could not be confirmed by confirmatory tests. Among the 1823 sera collected in 2015-2016, only 84 samples tested positive by gE ELISA, most of them corresponding to sera with reactivity above the optimized cut-offs in gB ELISAs. Screening for BoHV2 antibodies revealed a significantly increased prevalence among herds with singleton reactors, compared with the between-herd prevalence in French cattle herds. Altogether, these results provided suitable analytical strategies to limit the occurrence of false-positive BoHV1 reactions and inappropriate withdrawal of the BoHV1-free status, without alteration of diagnostic costs and reliability of eradication programs.
Assuntos
Anticorpos Antivirais/sangue , Herpesvirus Bovino 1/isolamento & purificação , Rinotraqueíte Infecciosa Bovina/sangue , Rinotraqueíte Infecciosa Bovina/epidemiologia , Animais , Bovinos , Ensaio de Imunoadsorção Enzimática/veterinária , França/epidemiologia , Rinotraqueíte Infecciosa Bovina/prevenção & controle , Vigilância em Saúde Pública/métodos , Curva ROC , Sensibilidade e EspecificidadeRESUMO
The dynamics between Mycobacterium avium subspecies paratuberculosis (MAP) infection and the immune response of goats naturally exposed to MAP were studied in a herd where the clinical expression of paratuberculosis had been observed. Four generations of goats were observed over a 33-month period: mothers of three different generations (G1, G2, G3) and their daughters, generation 4 (G4). A MAP infection status was defined according to the combined results of an IFN-γ assay, antibody response, faecal culture and post-mortem examination. Goats were defined as non-infected (NI), infected and non-shedder (INS), infected and shedder (IS) or atypical (A). Twenty-nine percent of goats were NI, 66% were infected and either shedding (14%) or not shedding (52%) MAP, and 5% were atypical. IFN-γ responses were detected first, followed by faecal shedding and antibody responses. The results showed that in goats naturally exposed to MAP, IFN-γ responses were regularly detected earlier in non-shedders than in young infected shedder goats and were stronger in shedder than in non-shedder goats. They were also higher in the mother goats than in their daughters. Goats shedding MAP or with positive antibody response at the beginning of their pregnancy are more likely to have an infected daughter positive to an IFN-γ assay by the age of 15 months.
Assuntos
Doenças das Cabras/microbiologia , Transmissão Vertical de Doenças Infecciosas/veterinária , Mycobacterium avium subsp. paratuberculosis , Paratuberculose/transmissão , Complicações Infecciosas na Gravidez/veterinária , Animais , Anticorpos Antibacterianos/sangue , Derrame de Bactérias , Fezes/microbiologia , Feminino , Doenças das Cabras/sangue , Doenças das Cabras/transmissão , Cabras , Interferon gama/sangue , Estudos Longitudinais , Paratuberculose/sangue , Gravidez , Complicações Infecciosas na Gravidez/sangue , Complicações Infecciosas na Gravidez/microbiologiaRESUMO
Small ruminant post-mortem testing programs were initially designed for monitoring the prevalence of prion disease. They are now considered as a potential alternative to genetic selection for eradicating/controlling classical scrapie at population level. If such policy should be implemented, its success would be crucially dependent on the efficiency of the surveillance system used to identify infected flocks. In this study, we first determined the performance of post-mortem classical scrapie detection in eight naturally affected goat herds (total n = 1961 animals) according to the age at culling. These results provided us with necessary parameters to estimate, through a Monte Carlo simulation model, the performance of scrapie detection in a commercial population. According to this model, whatever the number of tests performed, post mortem surveillance will have limited success in identifying infected herds. These data support the contention that scrapie eradication programs relying solely on post mortem testing in goats will probably fail. Considering the epidemiological and pathological similarities of scrapie in sheep and goats, the efficiency of scrapie surveillance in both species is likely to be similar.