ABSTRACT
The Norwegian Food Safety Authority (NFSA) and Norwegian Environmental Authority (NEA) asked the Norwegian Scientific Committee for Food Safety (Vitenskapskomiteen for mattrygghet, VKM) for an opinion on factors associated with the introduction of Chronic Wasting Disease (CWD) to Norway. VKM appointed a working group consisting of two members of the Panel on Biological Hazards, one member of Panel on Animal Health and Welfare, and two external experts to prepare the answer to the questions. The Panel on Biological Hazards has reviewed and revised the draft prepared by the working group and approved the opinion. CWD was diagnosed in March 2016 in a wild reindeer (Rangifer tarandus) from the Nordfjella mountain area in Norway and in May and June in two mooses (Alces alces) in Selbu in South Trøndelag County, approximately 300 km north from the first case. There is currently no information to determine the origin(s) of CWD agents in Norway. However, the sporadic or genetic (somatic mutation) occurrence of prion disease in cervids cannot be excluded, nor can introduction from North America or other countries. Furthermore, there is no evidence that it has not been circulating at low levels in the Norwegian cervid populations for years, but has not previously been identified. In this scientific opinion, information on prion diseases in general, and CWD in particular, is presented in the light of experiences with this disease in North America. Prions are among the most resilient pathogens known and dissemination of prions into ecosystems is likely to result in long-term problems. Prions bind strongly to soil and remain infectious. In CWD, prions are present in most peripheral organs and also shed into the environment via saliva, faeces, and urine, as well as with the placenta. CWD transmits easily among cervids, either through direct contact, or indirectly via the environment. Migration of animals is relevant for the spread between areas. Strain diversification might occur in CWD and may influence transmission properties of the agents. Clinical signs of CWD are non-specific and do not alone enable confirmation of the diagnosis. Analysis of tissue from the brainstem at the level of the obex by approved methods is necessary for diagnosis of CWD. Prion infectivity is assessed by bioassays, often involving transgenic mice. In vitro conversion assays, like protein misfolding cyclic amplification (PMCA), provide sensitive quantification of converting activity, which is a good approximation of infectivity. Genetic variation (polymorphisms) in the gene that encodes PrP (PRNP) can modulate sensitivity towards CWD. The level of such genetic variation in Norwegian wild and semi-domesticated cervids is currently unknown. Cattle and sheep are at very low risk of developing CWD and it is highly unlikely that prion diseases in sheep or cattle are the origin of CWD. Although transmission of CWD to humans has never been known to occur, and animals other than cervids have not been found to be infected, indicating a species barrier, this possibility cannot be excluded. Thus, measures for reduction of human exposure are recommended. Taking into account uncertainties regarding the plasticity of the CWD agents and the lack of transmission data from the Norwegian isolates, this scientific opinion considers the zoonotic risk of CWD to be very low.
ABSTRACT
Introduction: In the surgical management of cholesteatoma, one can opt for a closed technique (simple mastoidectomy) or open surgery (radical mastoidectomy). Open mastoidectomy with reconstruction of the posterior wall and the middle ear in a single surgery combines the advantages of both techniques, namely, adequate surgical exposure, eradication of cholesteatoma, and anatomical reconstruction of the middle ear structures. Objective: To evaluate the surgical results in the management of cholesteatoma through the technique of open mastoidectomy with reconstruction of the posterior wall and the middle ear in a single surgery. Methods: Prospective analytical observational study conducted between 2009 and 2012 with patients undergoing this surgical technique in the Hospital Universitario del Valle [University Hospital of Valle], performing preoperative clinical monitoring and quarterly postoperative tomography with previous assessments of hearing and pre- and postoperative audiometry. Results: Forty-five patients were studied. Mean postoperative follow-up was 28 months. Surgical success was achieved in 93.3% of patients, as measured by clinical and radiological follow-up. Hearing preservation was found after reconstruction of the hearing mechanism, based on measured audiometry, i.e., pure-tone average (PTA), using the statistical test for paired samples between preoperative and postoperative PTA. (95%CI -1.47-12.15). Residual cholesteatoma was present in 6.6% of cases; three to four times lower than the rate reported in the literature. Conclusions: This type of surgery can be considered a successful technique in the treatment of cholesteatoma in selected cases.
Introducción: El manejo del colesteatoma es quirúrgico. Se puede optar por una técnica cerrada (mastoidectomía simple) o técnica abierta (mastoidectomía radical). La mastoidectomía abierta con reconstrucción de la pared posterosuperior y reconstrucción del oído medio en un solo tiempo quirúrgico reúne las bondades de ambas técnicas: una adecuada exposición quirúrgica, erradicación del colesteatoma y reconstrucción anatómica de las estructuras del oído medio. Objetivo: Evaluar los resultados quirúrgicos en el manejo del colesteatoma con la técnica de mastoidectomía abierta con reconstrucción de la pared posterosuperior y el oído medio en un solo tiempo quirúrgico. Métodos: Estudio analítico observacional prospectivo realizado entre 2009-2012 con pacientes sometidos a esta técnica quirúrgica en el Hospital Universitario del Valle, realizándose un seguimiento clínico preoperatorio y postoperatorio trimestral, y evaluaciones previas con tomografía de oído y audiometría pre y postoperatoria. Resultados: Se estudiaron 45 pacientes. La media de seguimiento postoperatorio fue de 28 meses. Se alcanzó éxito quirúrgico en el 93.3% de los pacientes medidos por el seguimiento clínico y radiológico. Se encontró preservación de la audición después de la reconstrucción del mecanismo auditivo, medido con audiometría basada en el promedio tonal auditivo, mediante la prueba estadística para muestras pareadas entre la PTA preoperatoria y postoperatoria (IC95% -1.47-12.15). Se presentó colesteatoma residual en el 6.6%, tres a cuatro veces menor al reportado en la literatura. Conclusion: Este tipo de cirugía se puede considerar una técnica exitosa en el tratamiento de colesteatoma en casos seleccionados.
Subject(s)
Adult , Female , Humans , Male , Cholesteatoma, Middle Ear/surgery , Mastoid/surgery , Plastic Surgery Procedures/methods , Audiometry , Colombia , Follow-Up Studies , Hearing , Prospective Studies , Treatment OutcomeABSTRACT
Monoclonal antibodies (mAbs) specific for the abnormal prion protein isoform (PrPres) are indispensable for diagnosing chronic wasting disease (CWD). In this study, eight mAbs were developed by immunizing PrP knockout mice with recombinant elk PrP and an immunogenic PrP peptide. The reactivity of the mAbs to recombinant PrP and the PrP peptide was measured, and their isotypes were subsequently determined. Among them, four mAbs (B85-05, B85-08, B85-12, and B77-75) were shown by Western blotting to recognize proteinase K-treated brain homogenate derived from an elk suffering from CWD.
Subject(s)
Animals , Mice , Antibodies, Monoclonal , Blotting, Western , Brain , Mice, Knockout , Stress, Psychological , Wasting Disease, ChronicABSTRACT
In order to evaluate the genetic variability of the causative agent of cold water disease (CWD), plasmid profiling was used to characterize Flavobacterium (F.) psychrophilum isolates (n = 169). Size analysis of plasmids in F. psychrophilum isolates (n = 128) from several fish species demonstrated that six kinds of plasmids were harbored, and ayu isolates had different profiles compared to other isolates. Moreover, multiple isolates (n = 41) from CWD outbreaks in 2002 to 2003 at a single ayu farm were examined to determine differences between isolates from successive outbreaks and showed different profiles by the sources of seedlings.