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Wawer J, Andrukajtis M, Karczewski J, Zielińska-Jurek A, Piątek R. Fibrillar aggregates in powdered milk. J DAIRY RES 2023; 90:1-5. [PMID: 36694366 DOI: 10.1017/s002202992300002x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
This research paper addresses the hypothesis that powdered milk may contain amyloid fibrils. Amyloids are fibrillar aggregates of proteins. Up to this time, research on the presence of amyloids in food products are scarce. To check the hypothesis we performed thioflavin T fluorescence assay, X-ray powder diffraction, atomic force microscopy and fluorescence microscopy imaging. Our preliminary results show that commercially available milks contain fibrils that have features characteristic to amyloids. The obtained results can be interpreted in two opposite ways. The presence of amyloids could be considered as a hazard due to the fact that food products may induce amyloid related diseases. On the other hand, the presence of amyloids in traditionally consumed foodstuffs could serve as proof that fibrils of food proteins do not pose a threat for consumers.
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Affiliation(s)
- Jarosław Wawer
- Department of Physical Chemistry, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza Str. 11/12, 80-233 Gdańsk, Poland
| | - Martyna Andrukajtis
- Department of Physical Chemistry, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza Str. 11/12, 80-233 Gdańsk, Poland
| | - Jakub Karczewski
- Faculty of Applied Physics and Mathematics, Institute of Nanotechnology and Materials Science, Gdańsk University of Technology, Narutowicza Str. 11/12, 80-233 Gdańsk, Poland
| | - Anna Zielińska-Jurek
- Department of Process Engineering and Chemical Technology, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza Str. 11/12, 80-233 Gdańsk, Poland
| | - Rafał Piątek
- Department of Molecular Biotechnology and Microbiology, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza Str. 11/12, 80-233 Gdańsk, Poland
- BioTechMed Center, Gdańsk University of Technology, Narutowicza Str. 11/12, 80-233 Gdańsk, Poland
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2
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Non-human primates in prion diseases. Cell Tissue Res 2022; 392:7-20. [PMID: 35661921 DOI: 10.1007/s00441-022-03644-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 05/21/2022] [Indexed: 11/02/2022]
Abstract
The fascinating history of prion diseases is intimately linked to the use of nonhuman primates as experimental models, which brought so fundamental and founding information about transmissibility, pathogenesis, and resistance of prions. These models are still of crucial need for risk assessment of human health and may contribute to pave a new way towards the moving field of prion-like entities which now includes the main human neurodegenerative diseases (especially Alzheimer's and Parkinson's diseases).
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James WPT. A Dissenter's Journey. Annu Rev Nutr 2021; 41:1-18. [PMID: 34115517 DOI: 10.1146/annurev-nutr-101220-114101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
After I studied medicine, my career took an early and unusual course when I was offered a clinical research post in Jamaica dealing with childhood malnutrition, of which I knew nothing. My subsequent nutritional explorations allowed gastrointestinal and metabolic analyses to have an impact on several public health policies. The biggest challenges came from unexpected political demands: coping with poor school performers in the Caribbean; addressing UK public health initiatives in health education; breaking the siege of Sarajevo; developing a Food Standards Agency as a sudden need for Tony Blair as incoming prime minister; dealing with widespread bovine spongiform encephalopathy in Europe; and responding to a United Nations request to assess global malnutrition. This last task revealed the need for a lifelong approach to nutrition, which also encompassed pregnancy. But perhaps the biggest challenge was establishing the criteria for obesity assessment, management, and prevention for policy makers across the globe. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- W Philip T James
- Department of Population Health, London School of Hygiene and Tropical Medicine, London WC1E 7HT, United Kingdom;
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4
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Comoy EE, Mikol J, Deslys JP. Unexpected prion phenotypes in experimentally transfused animals: predictive models for humans? Prion 2018; 12:1-8. [PMID: 30080439 PMCID: PMC6277188 DOI: 10.1080/19336896.2018.1505399] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 07/24/2018] [Indexed: 12/12/2022] Open
Abstract
The recently reevaluated high prevalence of healthy carriers (1/2,000 in UK) of variant Creutzfeldt-Jakob Disease (v-CJD), whose blood might be infectious, suggests that the evolution of this prion disease might not be under full control as expected. After experimental transfusion of macaques and conventional mice with blood derived from v-CJD exposed (human and animal) individuals, we confirmed in these both models the transmissibility of v-CJD, but we also observed unexpected neurological syndromes transmissible by transfusion: despite their prion etiology confirmed through transmission experiments, these original cases would escape classical prion diagnosis, notably in the absence of detectable abnormal PrP with current techniques. It is noteworthy that macaques developed an original, yet undescribed myelopathic syndrome associating demyelination and pseudo-necrotic lesions of spinal cord, brainstem and optical tract without affecting encephalon, which is rather evocative of spinal cord disease than prion disease in human medicine. These observations strongly suggest that the spectrum of human prion diseases may extend the current field restricted to the phenotypes associated to protease-resistant PrP, and may notably include spinal cord diseases.
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Affiliation(s)
- Emmanuel E. Comoy
- Prion Research Unit, Institut François Jacob, Division of Fundamental Research, Commissariat à l’Energie Atomique, Fontenay-aux-Roses, France
| | - Jacqueline Mikol
- Prion Research Unit, Institut François Jacob, Division of Fundamental Research, Commissariat à l’Energie Atomique, Fontenay-aux-Roses, France
| | - Jean-Philippe Deslys
- Prion Research Unit, Institut François Jacob, Division of Fundamental Research, Commissariat à l’Energie Atomique, Fontenay-aux-Roses, France
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Seed CR, Hewitt PE, Dodd RY, Houston F, Cervenakova L. Creutzfeldt-Jakob disease and blood transfusion safety. Vox Sang 2018; 113:220-231. [PMID: 29359329 DOI: 10.1111/vox.12631] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 11/16/2017] [Accepted: 12/19/2017] [Indexed: 01/09/2023]
Abstract
Transmissible spongiform encephalopathies (TSEs) are untreatable, fatal neurologic diseases affecting mammals. Human disease forms include sporadic, familial and acquired Creutzfeldt-Jakob disease (CJD). While sporadic CJD (sCJD) has been recognized for near on 100 years, variant CJD (vCJD) was first reported in 1996 and is the result of food-borne transmission of the prion of bovine spongiform encephalopathy (BSE, 'mad cow disease'). Currently, 230 vCJD cases have been reported in 12 countries, the majority in the UK (178) and France (27). Animal studies demonstrated highly efficient transmission of natural scrapie and experimental BSE by blood transfusion and fuelled concern that sCJD was potentially transfusion transmissible. No such case has been recorded and case-control evaluations and lookback studies indicate that, if transfusion transmission occurs at all, it is very rare. In contrast, four cases of apparent transfusion transmission of vCJD infectivity have been identified in the UK. Risk minimization strategies in response to the threat of vCJD include leucodepletion, geographically based donor deferrals and deferral of transfusion recipients. A sensitive and specific, high-throughput screening test would provide a potential path to mitigation but despite substantial effort no such test has yet appeared. The initial outbreak of vCJD appears to be over, but concern remains about subsequent waves of disease among those already infected. There is considerable uncertainty about the size of the infected population, and there will be at least a perception of some continuing risk to blood safety. Accordingly, at least some precautionary measures will remain in place and continued surveillance is necessary.
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Affiliation(s)
- C R Seed
- Australian Red Cross Blood Service, Perth, WA, Australia
| | | | - R Y Dodd
- American Red Cross Scientific Affairs, Gaithersburg, MD, USA
| | - F Houston
- The Roslin Institute, University of Edinburgh, Midlothian, Scotland
| | - L Cervenakova
- The Plasma Protein Therapeutics Association (PPTA), Annapolis, MD, USA
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Al-Zoughool M, Oraby T, Krewski D. A Bayesian back-calculation method to estimate the risk of bovine spongiform encephalopathy (BSE) in Canada during the period 1996-2011. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2016; 79:700-712. [PMID: 27556564 DOI: 10.1080/15287394.2016.1174004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Seventeen typical cases of bovine spongiform encephalopathy (BSE) were detected in Canada the period of 2003-2011. The clinical incidence of BSE was censored by early slaughter, death, or exportation of infected cattle due to the long incubation period of BSE disease. The aim of this study was to estimate the infection incidence of BSE in birth cohorts during 1996-2004 and project infection frequency through to 2007. An estimate of the number of asymptomatic infected cattle slaughtered for human consumption is also provided. The number of incident, asymptomatic cases was assumed to follow a Poisson process. A Bayesian back-calculation approach was used to project the risk of contracting BSE in those birth cohorts. Model parameters and inputs were taken from scientific literature and governmental data sources. The projected number of infected cattle in birth cohorts spanning the period 1996-2007 was 492, with median 95% credible interval 258-830. If the requirement to remove specified risk material (SRM) from cattle prior to entering the food chain was not in place, the predicted number of slaughtered infected in the human food chain from 1996-2010 was 298, with a 95% credible interval 156-500. The magnitude of the BSE epidemic in Canada for 1996-2007 birth cohorts was estimated to be approximately 28-fold higher than the number of clinical cases detected through to October 2011. Although some of those cattle were slaughtered for human consumption, the requirement of SRM removal may have prevented most of the infectious material from entering the food chain.
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Affiliation(s)
- Mustafa Al-Zoughool
- a Department of Community and Environmental Health , King Saud bin Abdulaziz University for Health Sciences , Riyadh , Saudi Arabia
| | - Tamer Oraby
- b School of Mathematical and Statistical Sciences , University of Texas Rio Grande Valley , Edinburg , Texas , USA
| | - Daniel Krewski
- c McLaughlin Center for Population Health Risk Assessment , University of Ottawa , Ottawa , Canada
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Al-Zoughool M, Cottrell D, Elsaadany S, Murray N, Oraby T, Smith R, Krewski D. Mathematical Models for Estimating the Risks of Bovine Spongiform Encephalopathy (BSE). JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2015; 18:71-104. [PMID: 26158300 DOI: 10.1080/10937404.2015.1036963] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
When the bovine spongiform encephalopathy (BSE) epidemic first emerged in the United Kingdom in the mid 1980s, the etiology of animal prion diseases was largely unknown. Risk management efforts to control the disease were also subject to uncertainties regarding the extent of BSE infections and future course of the epidemic. As understanding of BSE increased, mathematical models were developed to estimate risk of BSE infection and to predict reductions in risk in response to BSE control measures. Risk models of BSE-transmission dynamics determined disease persistence in cattle herds and relative infectivity of cattle prior to onset of clinical disease. These BSE models helped in understanding key epidemiological features of BSE transmission and dynamics, such as incubation period distribution and age-dependent infection susceptibility to infection with the BSE agent. This review summarizes different mathematical models and methods that have been used to estimate risk of BSE, and discusses how such risk projection models have informed risk assessment and management of BSE. This review also provides some general insights on how mathematical models of the type discussed here may be used to estimate risks of emerging zoonotic diseases when biological data on transmission of the etiological agent are limited.
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Affiliation(s)
- Mustafa Al-Zoughool
- a Department of Community and Environmental Health , King Saud Bin Abdulaziz University for Health Sciences , Riyadh , Saudi Arabia
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One Health and Food Safety. CONFRONTING EMERGING ZOONOSES 2014. [PMCID: PMC7121645 DOI: 10.1007/978-4-431-55120-1_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Many, if not most, of all important zoonoses relate in some way to animals in the food production chain. Therefore food becomes an important vehicle for many zoonotic pathogens. One of the major issues in food safety over the latest decades has been the lack of cross-sectoral collaboration across the food production chain. Major food safety events have been significantly affected by the lack of collaboration between the animal health, the food control, and the human health sector. One Health formulates clearly both the need for, and the benefit of cross-sectoral collaboration. Here we will focus on the human health risk related to zoonotic microorganisms present both in food animals and food derived from these animals, and typically transmitted to humans through food. Some diseases have global epidemic—or pandemic—potential, resulting in dramatic action from international organizations and national agricultural- and health authorities in most countries, for instance as was the case with avian influenza. Other diseases relate to the industrialized food production chain and have been—in some settings—dealt with efficiently through farm-to-fork preventive action in the animal sector, e.g. Salmonella. Finally, an important group of zoonotic diseases are ‘neglected diseases’ in poor settings, while they have been basically eradicated in affluent economies through vaccination and culling policies in the animal sector, e.g. Brucella. Here we will discuss these three different foodborne disease categories, paying extra attention to the important problem of antimicrobial resistance (AMR). In addition, we present some of the One Health inspired solutions that may help reduce the threat of several of the foodborne diseases discussed.
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Small-molecule theranostic probes: a promising future in neurodegenerative diseases. Int J Cell Biol 2013; 2013:150952. [PMID: 24324497 PMCID: PMC3845517 DOI: 10.1155/2013/150952] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 09/03/2013] [Indexed: 12/15/2022] Open
Abstract
Prion diseases are fatal neurodegenerative illnesses, which include Creutzfeldt-Jakob disease in humans and scrapie, chronic wasting disease, and bovine spongiform encephalopathy in animals. They are caused by unconventional infectious agents consisting primarily of misfolded, aggregated, β -sheet-rich isoforms, denoted prions, of the physiological cellular prion protein (PrP(C)). Many lines of evidence suggest that prions (PrP(Sc)) act both as a template for this conversion and as a neurotoxic agent causing neuronal dysfunction and cell death. As such, PrP(Sc) may be considered as both a neuropathological hallmark of the disease and a therapeutic target. Several diagnostic imaging probes have been developed to monitor cerebral amyloid lesions in patients with neurodegenerative disorders (such as Alzheimer's disease, Parkinson's disease, and prion disease). Examples of these probes are Congo red, thioflavin T, and their derivatives. We synthesized a series of styryl derivatives, denoted theranostics, and studied their therapeutic and/or diagnostic potentials. Here we review the salient traits of these small molecules that are able to detect and modulate aggregated forms of several proteins involved in protein misfolding diseases. We then highlight the importance of further studies for their practical implications in therapy and diagnostics.
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10
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Prion diseases. Neurogenetics 2012. [DOI: 10.1017/cbo9781139087711.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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11
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Garske T, Ghani AC. Uncertainty in the tail of the variant Creutzfeldt-Jakob disease epidemic in the UK. PLoS One 2010; 5:e15626. [PMID: 21203419 PMCID: PMC3009744 DOI: 10.1371/journal.pone.0015626] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 11/18/2010] [Indexed: 11/18/2022] Open
Abstract
Despite low case numbers the variant Creutzfeldt-Jakob disease epidemic poses many challenges for public health planning due to remaining uncertainties in disease biology and transmission routes. We develop a stochastic model for variant CJD transmission, taking into account the known transmission routes (food and red-cell transfusion) to assess the remaining uncertainty in the epidemic. We use Bayesian methods to obtain scenarios consistent with current data. Our results show a potentially long but uncertain tail in the epidemic, with a peak annual incidence of around 11 cases, but the 95% credibility interval between 1 and 65 cases. These cases are predicted to be due to past food-borne transmissions occurring in previously mostly unaffected genotypes and to transmissions via blood transfusion in all genotypes. However, we also show that the latter are unlikely to be identifiable as transfusion-associated cases by case-linking. Regardless of the numbers of future cases, even in the absence of any further control measures, we do not find any self-sustaining epidemics.
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Affiliation(s)
- Tini Garske
- Department of Infectious Disease Epidemiology, Medical Research Council Centre of Outbreak Analysis and Modelling, Imperial College London, London, United Kingdom.
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13
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Chadeau-Hyam M, Clarke PS, Guihenneuc-Jouyaux C, Cousens SN, Will RG, Ghani AC. An application of hidden Markov models to the French variant Creutzfeldt-Jakob disease epidemic. J R Stat Soc Ser C Appl Stat 2010. [DOI: 10.1111/j.1467-9876.2010.00714.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Arnold ME, Hawkins SAC, Green R, Dexter I, Wells GAH. Pathogenesis of experimental bovine spongiform encephalopathy (BSE): estimation of tissue infectivity according to incubation period. Vet Res 2009; 40:8. [PMID: 18950589 PMCID: PMC2695012 DOI: 10.1051/vetres:2008046] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Accepted: 10/23/2008] [Indexed: 11/14/2022] Open
Abstract
This paper reports the results of tissue infectivity assays of bovine spongiform encephalopathy (BSE) agent in orally exposed cattle at stages during the incubation period. Estimations of the titre of infectivity in central nervous system (CNS), certain peripheral nerve ganglia and distal ileum tissue were made according to time post exposure from the relationship between incubation period and dose for RIII mice and C57bl mice using data from titrations of brain material from cases of BSE. The rate of increase of infectivity in the bovine CNS was then estimated, taking into account these tissue infectivity titres, the variability of the brain titre of clinical field cases of BSE, and the probability density of the expected number of months before clinical onset of each infected bovine. The doubling time for CNS was shown to equal 1.2 months. The titre in the thoracic dorsal root ganglia (DRG) was, on average, approximately 1 log units less than CNS, and cervical DRG approximately 0.5 log less than thoracic DRG. The pattern of increase of infectivity in the distal ileum is that of an initial increase up to 14-18 months post exposure, followed by a decrease, which is likely to be highly variable between animals. These results will be informative for future risk assessments of BSE, especially in relation to reviewing current control measures.
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Affiliation(s)
- Mark Edward Arnold
- Veterinary Laboratories Agency, Woodham Lane, New Haw, Addlestone, Surrey, KT15 3NB, United Kingdom.
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Ducrot C, Arnold M, de Koeijer A, Heim D, Calavas D. Review on the epidemiology and dynamics of BSE epidemics. Vet Res 2008; 39:15. [DOI: 10.1051/vetres:2007053] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2007] [Accepted: 10/23/2007] [Indexed: 11/14/2022] Open
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Clarke P, Will RG, Ghani AC. Is there the potential for an epidemic of variant Creutzfeldt-Jakob disease via blood transfusion in the UK? J R Soc Interface 2007; 4:675-84. [PMID: 17287181 PMCID: PMC2373392 DOI: 10.1098/rsif.2007.0216] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The discovery of three individuals suspected to have contracted variant Creutzfeldt-Jakob disease (vCJD) through blood transfusions has heightened concerns that a secondary epidemic via human-to-human transmission could occur in the UK. The Department of Health responded immediately to this threat by banning those who had received blood transfusions since 1980 from donating blood. In this paper, we conduct a sensitivity analysis to explore the potential size of a blood-borne vCJD epidemic and investigate the effectiveness of public health interventions. A mathematical model was developed together with an expression for the basic reproduction number (R0). The sensitivity of model predictions to unknown parameters determining the transmission of vCJD via infected blood was assessed under pessimistic modelling assumptions. We found that the size of the epidemic (up until 2080) was bounded above by 900 cases, with self-sustaining epidemics (R0>1) also possible; but the scenarios under which such epidemics could arise were found to be biologically implausible. Under optimistic assumptions, public health interventions reduced the upper bound to 250 and further still when only biologically plausible scenarios were considered. Our results support the belief that scenarios leading to large or self-sustaining epidemics are possible but unlikely, and that public health interventions were effective.
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Affiliation(s)
- Paul Clarke
- Department of Epidemiology and Population Health, London School of Hygiene and Tropical MedicineKeppel Street, London WC1E 7HT, UK
| | - Robert G Will
- National CJD Surveillance Unit, Western General HospitalCrewe Road, Edinburgh EH4 2XU, UK
| | - Azra C Ghani
- Department of Epidemiology and Population Health, London School of Hygiene and Tropical MedicineKeppel Street, London WC1E 7HT, UK
- Author for correspondence ()
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Mawhinney S, Pape WJ, Forster JE, Anderson CA, Bosque P, Miller MW. Human prion disease and relative risk associated with chronic wasting disease. Emerg Infect Dis 2007; 12:1527-35. [PMID: 17176567 PMCID: PMC3290936 DOI: 10.3201/eid1210.060019] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Colorado death certificate data from 1979 through 2001 show that the risk for Creutzfeldt-Jakob disease did not increase for residents of counties where chronic wasting disease is endemic among deer and elk. The transmission of the prion disease bovine spongiform encephalopathy (BSE) to humans raises concern about chronic wasting disease (CWD), a prion disease of deer and elk. In 7 Colorado counties with high CWD prevalence, 75% of state hunting licenses are issued locally, which suggests that residents consume most regionally harvested game. We used Colorado death certificate data from 1979 through 2001 to evaluate rates of death from the human prion disease Creutzfeldt-Jakob disease (CJD). The relative risk (RR) of CJD for CWD-endemic county residents was not significantly increased (RR 0.81, 95% confidence interval [CI] 0.40–1.63), and the rate of CJD did not increase over time (5-year RR 0.92, 95% CI 0.73–1.16). In Colorado, human prion disease resulting from CWD exposure is rare or nonexistent. However, given uncertainties about the incubation period, exposure, and clinical presentation, the possibility that the CWD agent might cause human disease cannot be eliminated.
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Affiliation(s)
- Samantha Mawhinney
- University of Colorado at Denver, Health Sciences Center, Denver, Colorado 80262, USA.
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18
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Clarke PS, Ghani AC. A note on parameter estimation for variant Creutzfeldt–Jakob disease epidemic models. Stat Med 2007; 26:546-52. [PMID: 16612835 DOI: 10.1002/sim.2567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A recent series of papers has raised issues regarding estimation of the key epidemiological parameters of variant Creutzfeldt-Jakob disease (vCJD) from fitting survival models to case data. In particular, it was stated that the scale of the epidemic cannot be estimated and must be fixed in any analysis. We show that this problem is an artefact of the approximate likelihood used in these papers to facilitate model-fitting, and is not a concern if estimation is based on the full likelihood. We also address comments in these papers regarding the choice of incubation period distribution.
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Affiliation(s)
- Paul S Clarke
- Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK.
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Clarke P, Ghani AC. Projections of the future course of the primary vCJD epidemic in the UK: inclusion of subclinical infection and the possibility of wider genetic susceptibility. J R Soc Interface 2006; 2:19-31. [PMID: 16849160 PMCID: PMC1578257 DOI: 10.1098/rsif.2004.0017] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The incidence of variant Creutzfeldt-Jakob disease (vCJD) in the United Kingdom appears to be in decline, with only four deaths reported this year (to 6 September 2004). However, results of a survey of lymphoreticular tissues have suggested a substantially higher prevalence of vCJD than expected from the clinical data alone. There are two plausible explanations for this discrepancy: first, a proportion of those infected will not develop clinical disease (subclinical infection); and second, the genetic group in which no clinical cases of vCJD have yet occurred is susceptible. Using mathematical models for the primary transmission of bovine spongiform encephalopathy to humans, we explore the impact of these hypotheses on case predictions. Under the first hypothesis, the results suggest relatively few future cases will arise via primary transmission, but that these cases are a small proportion of those infected, with most having subclinical infection. Under the second hypothesis, results suggest a maximum fivefold increase in cases, but this hypothesis is unable to account for the discrepancy between clinical cases and the estimated prevalence. Predictions of future cases of vCJD therefore remain uncertain, particularly given the recent identification of additional cases infected via blood transfusion.
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Affiliation(s)
- Paul Clarke
- Department of Infectious Disease Epidemiology, Imperial College London, St Mary's Campus, Norfolk Place, London W2 1PG, UK.
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Joffe M, Mindell J. Complex causal process diagrams for analyzing the health impacts of policy interventions. Am J Public Health 2006; 96:473-9. [PMID: 16449586 PMCID: PMC1470508 DOI: 10.2105/ajph.2005.063693] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Causal diagrams are rigorous tools for controlling confounding. They also can be used to describe complex causal systems, which is done routinely in communicable disease epidemiology. The use of change diagrams has advantages over static diagrams, because change diagrams are more tractable, relate better to interventions, and have clearer interpretations. Causal diagrams are a useful basis for modeling. They make assumptions explicit, provide a framework for analysis, generate testable predictions, explore the effects of interventions, and identify data gaps. Causal diagrams can be used to integrate different types of information and to facilitate communication both among public health experts and between public health experts and experts in other fields. Causal diagrams allow the use of instrumental variables, which can help control confounding and reverse causation.
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Affiliation(s)
- Michael Joffe
- Department of Epidemiology and Public Health, Imperial College, St Mary's Campus, Norfolk Pl, London W2 1PF, United Kingdom.
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Ludlam CA, Turner ML. Managing the risk of transmission of variant Creutzfeldt Jakob disease by blood products. Br J Haematol 2006; 132:13-24. [PMID: 16371015 DOI: 10.1111/j.1365-2141.2005.05796.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Whereas plasma-derived clotting factor concentrates now have a very good safety record for not being infectious for lipid enveloped viruses, concern has arisen about the possibility that prion diseases might be transmitted by blood products. There is epidemiological evidence that classical sporadic Creutzfeld Jakob disease (CJD) is not transmitted by blood transfusion. There is now good evidence that the abnormal prion associated with variant CJD can be transmitted by transfusion of fresh blood components and infect recipients. To reduce the risk of the pathological prion in the UK infecting recipients of clotting factor concentrates, these are now only manufactured from imported plasma collected from countries where there has not been bovine spongiform encephalopathy (BSE) in cattle and the risk of variant CJD in the population is, therefore, considered negligible. The safety of these concentrates is also enhanced because prion protein is, to an appreciable extent, excluded by the manufacturing process from the final product. To help reduce the chance of prion transmission by fresh blood products, donations are leucodepleted, there is increasing use of imported fresh frozen plasma (especially for treating children) and potential donors, who have been recipients of blood since 1980 (the beginning of the BSE epidemic in cattle) are deferred.
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Abstract
Prions are infectious pathogens principally composed of abnormal forms of a protein encoded in the host genome. They cause lethal neurodegenerative conditions including CJD, GSS, and kuru in humans and scrapie and bovine spongiform encephalopathy in domestic animals. Remarkably, distinct strains of prions occur despite absence of an agent-specific genome: misfolded proteins themselves may encode strain diversity--with wide implications in biology. The arrival of variant CJD, and the experimental confirmation that it is caused by infection with BSE-like prions, has focussed research on early diagnosis and treatment. Recent advances lead to considerable optimism that effective human therapies may now be developed. While several drugs have been tried in small numbers of patients, there is no clear evidence of efficacy of any agent and controlled clinical trials are urgently needed. Importantly, there is increasing recognition that fundamental processes involved in prion propagation--seeded aggregation of misfolded host proteins--are of far wider significance, not least in understanding the commoner neurodegenerative diseases that pose such a major and increasing challenge for healthcare in an ageing population.
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Affiliation(s)
- J Collinge
- MRC Prion Unit and National Prion Clinic, Institute of Neurology and National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK.
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24
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Streftaris G, Gibson GJ. Bayesian analysis of experimental epidemics of foot-and-mouth disease. Proc Biol Sci 2004; 271:1111-7. [PMID: 15306359 PMCID: PMC1691714 DOI: 10.1098/rspb.2004.2715] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We investigate the transmission dynamics of a certain type of foot-and-mouth disease (FMD) virus under experimental conditions. Previous analyses of experimental data from FMD outbreaks in non-homogeneously mixing populations of sheep have suggested a decline in viraemic level through serial passage of the virus, but these do not take into account possible variation in the length of the chain of viral transmission for each animal, which is implicit in the non-observed transmission process. We consider a susceptible-exposed-infectious-removed non-Markovian compartmental model for partially observed epidemic processes, and we employ powerful methodology (Markov chain Monte Carlo) for statistical inference, to address epidemiological issues under a Bayesian framework that accounts for all available information and associated uncertainty in a coherent approach. The analysis allows us to investigate the posterior distribution of the hidden transmission history of the epidemic, and thus to determine the effect of the length of the infection chain on the recorded viraemic levels, based on the posterior distribution of a p-value. Parameter estimates of the epidemiological characteristics of the disease are also obtained. The results reveal a possible decline in viraemia in one of the two experimental outbreaks. Our model also suggests that individual infectivity is related to the level of viraemia.
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Affiliation(s)
- George Streftaris
- Actuarial Mathematics and Statistics, School of Mathematical and Computer Sciences, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, UK.
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Ramasamy I. The risk of accidental transmission of transmissible spongiform encephalopathy: identification of emerging issues. Public Health 2004; 118:409-20. [PMID: 15313594 DOI: 10.1016/j.puhe.2003.12.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2003] [Revised: 12/11/2003] [Accepted: 12/11/2003] [Indexed: 11/29/2022]
Abstract
The transmissible spongiform encephalopathies (TSEs), thought to be caused by prions, are fatal neurodegenerative disorders of humans and animals. Despite their rarity, human prion diseases have received prominence because the consumption of prion-contaminated meat from cattle with bovine spongiform encephalopathy (BSE) is thought to be responsible for the emergence of variant Creutzfeldt-Jakob disease (vCJD) in humans. Clinical criteria for the diagnosis of vCJD is now available. Recent, more startling evidence suggests that the clinical presentation of vCJD may vary and that patients may present as classical (sporadic) CJD or may have subclinical infection and be apparently healthy. These patients may still pose a risk of iatrogenic transmission through surgical or medical (blood transfusion) procedures. The aim of future work is to develop preclinical screening tests for the identification of infected but still healthy individuals. The future course of vCJD is still uncertain. Modelling studies to predict the cases of vCJD depend on the date of origin of BSE and time of infection, which is, at best, only approximated. As the number of cases of BSE in the UK declines, the risk of BSE in other countries from imported cattle or meat and bone meal from the UK has been increasing. It is also recognized that other animal species (farmed, domestic and wild animals) other than cows are susceptible to TSEs. The possibility of interspecies transmission of TSEs and the global presence of the disease suggests a need for a co-ordinated worldwide risk management approach to eradicate TSEs.
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Affiliation(s)
- I Ramasamy
- Department of Chemical Pathology, Newham General Hospital, Glen Road, Plaistow, London E13 8RU, UK.
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Harney MS, Ghani AC, Donnelly CA, Walsh RM, Walsh M, Howley R, Brett F, Farrell M. vCJD risk in the Republic of Ireland. BMC Infect Dis 2003; 3:28. [PMID: 14641933 PMCID: PMC305349 DOI: 10.1186/1471-2334-3-28] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2003] [Accepted: 11/26/2003] [Indexed: 11/10/2022] Open
Abstract
Background The Republic of Ireland has the second highest incidence of BSE worldwide. Only a single case of vCJD has been identified to date. Methods We estimate the total future number of clinical cases of vCJD using an established mathematical model, and based on infectivity of bovine tissue calculated from UK data and on the relative exposure to BSE contaminated meat. Results We estimate 1 future clinical case (95% CI 0 – 15) of vCJD in the Republic of Ireland. Irish exposure is from BSE infected indigenous beef products and from imported UK beef products. Additionally, 2.5% of the Irish population was exposed to UK beef through residing in the UK during the 'at-risk' period. The relative proportion of risk attributable to each of these three exposures individually is 2:2:1 respectively. Conclusions The low numbers of future vCJD cases estimated in this study is reassuring for the Irish population and for other countries with a similar level of BSE exposure.
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Affiliation(s)
- Michael S Harney
- CJD Surveillance Unit, Beaumont Hospital, Dublin, Ireland
- Department of Otolaryngology, Beaumont Hospital, Dublin, Ireland
| | - Azra C Ghani
- Department of Infectious Disease Epidemiology, Imperial College London, UK
| | - CA Donnelly
- Department of Infectious Disease Epidemiology, Imperial College London, UK
| | | | - Michael Walsh
- Department of Otolaryngology, Beaumont Hospital, Dublin, Ireland
| | - Rachel Howley
- CJD Surveillance Unit, Beaumont Hospital, Dublin, Ireland
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27
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Ghani AC. Commentary: Predicting the unpredictable: the future incidence of variant Creutzfeldt-Jakob disease. Int J Epidemiol 2003; 32:792-3. [PMID: 14559751 DOI: 10.1093/ije/dyg276] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Azra C Ghani
- Department of Infectious Disease Epidemiology, Imperial College, London, UK
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28
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Cooper JD, Bird SM. Predicting incidence of variant Creutzfeldt-Jakob disease from UK dietary exposure to bovine spongiform encephalopathy for the 1940 to 1969 and post-1969 birth cohorts. Int J Epidemiol 2003; 32:784-91. [PMID: 14559750 DOI: 10.1093/ije/dyg248] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND To investigate variant Creutzfeldt-Jakob disease (vCJD) incubation period, transmission barrier, and short-term vCJD predictions for methionine homozygotes in 1940-1969 and post-1969 birth cohorts by use of gender- and age-specific exposure intensities to bovine spongiform encephalopathy (BSE), based on consumption of beef mechanically recovered meat (MRM) and head meat. METHODS Simulation (from vCJD infections generated randomly from gender and age-specific dietary exposure intensities to BSE), constrained to equal the 47 and 64 vCJD onsets before 2001 in 1940-1969 and post-1969 birth cohorts, was used to estimate lognormal (and other) incubation mean and standard deviation which fitted the calendar year distribution of observed vCJD onsets; and to explore exponential decay in susceptibility to infection with age above 15 years. RESULTS For the post-1969 birth cohort, the best-fitting lognormal incubation period mean of 11 years (SD 1.5 years and 195 infections) was associated with 194 vCJD onsets (64 before 2001, 105 in 2001-2005, and 25 in 2006-2010). About one-fifth of simulated vCJD onsets before 2001 arose from infections in 1990-1996; age and gender of simulated and observed vCJD patients agreed closely. For the 1940-1969 birth cohort, well-fitting lognormal means ranged widely, the marginally best fitting being 26 years (SD 16.5 years and 382 infections; 47 vCJD onsets before 2001, 58 in 2001-2005, and 63 in 2006-2010). An age-dependent susceptibility function was required to match the age distribution of vCJD patients in the 1940-1969 birth cohort. CONCLUSIONS About three-fifths of predicted vCJD onsets are expected to be in males, and nearly two-thirds of vCJD onsets in 2001-2005 are expected to be in post-1969 birth cohort according to best-fitting predictions.
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Affiliation(s)
- J D Cooper
- MRC Biostatistics Unit and Department of Medical Genetics, Cambridge, UK
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29
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Trevitt CR, Singh PN. Variant Creutzfeldt-Jakob disease: pathology, epidemiology, and public health implications. Am J Clin Nutr 2003; 78:651S-656S. [PMID: 12936961 DOI: 10.1093/ajcn/78.3.651s] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Prion diseases, or transmissible spongiform encephalopathies, include Creutzfeldt-Jakob disease (CJD) in humans and scrapie and bovine spongiform encephalopathy (BSE) in animals. These neurodegenerative diseases are invariably fatal and can be transmitted by inoculation or dietary exposure. They are associated with the accumulation of an altered, disease-associated form of the normal prion protein. Pathologically, prion diseases result in neuronal cell death and a characteristic spongiform appearance of the brain tissue. The emergence of a variant form of CJD (vCJD) in the United Kingdom in 1996 has been causally and experimentally linked to the UK BSE epidemic in the 1980s and early 1990s. The finding that BSE is transmissible to different animal species, unlike previously characterized prion diseases such as sheep scrapie, has raised enormous public health concerns worldwide. Although it is not yet possible to gauge the size of a potential vCJD epidemic, preliminary data indicate a significant dietary exposure to BSE-infected material in Britain and wider implications of the transmissibility of prion diseases. The threat to public health has intensified research efforts to understand the molecular basis of prion diseases, understand their transmission between species, improve methods of diagnosis, and develop therapeutic strategies for treatment and prevention of disease. In this review, we summarize current data on the pathology of BSE and vCJD and the epidemiology of vCJD, and we outline public health implications based on these data, emphasizing preventative measures and areas of research for screening and diagnosis.
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Affiliation(s)
- Clare R Trevitt
- MRC Prion Unit, Division of Neuroscience, Faculty of Medicine, Imperial College, Norfolk Place, London, UK.
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30
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Bhakdi S, Bohl J. Prions, mad cow disease, and preventive measures: a critical appraisal. Med Microbiol Immunol 2003; 192:117-22. [PMID: 12819966 DOI: 10.1007/s00430-003-0184-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Sucharit Bhakdi
- Institute of Medical Microbiology and Hygiene, Johannes Gutenberg-University, Hochhaus am Augustusplatz, 55101 Mainz, Germany.
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31
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Ghani AC, Ferguson NM, Donnelly CA, Anderson RM. Short-term projections for variant Creutzfeldt-Jakob disease onsets. Stat Methods Med Res 2003; 12:191-201. [PMID: 12828241 DOI: 10.1191/0962280203sm327ra] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Projections of both the short- and long-term course of the variant Creutzfeldt-Jakob disease (vCJD) epidemic in Great Britain have demonstrated great uncertainty due to the lack of knowledge of key aspects of the biology and epidemiology of this new disease. Such projections are sensitive to assumptions made regarding the pattern of exposure to BSE-infected animals, the effectiveness of control measures introduced in 1989 and 1996 in reducing this exposure, the functional form of the incubation period distribution and patterns of age-dependent susceptibility/exposure. This paper provides short-term projections for vCJD onsets using the time- and age-distributed onset data to the end of 2000, with results that are directly comparable to the other papers in this issue. These results demonstrate the continued uncertainty in the future scale of this disease.
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Affiliation(s)
- Azra C Ghani
- Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College, London, UK.
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32
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Ghani AC, Donnelly CA, Ferguson NM, Anderson RM. Updated projections of future vCJD deaths in the UK. BMC Infect Dis 2003; 3:4. [PMID: 12716457 PMCID: PMC156616 DOI: 10.1186/1471-2334-3-4] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2003] [Accepted: 04/27/2003] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Past projections of the future course of the vCJD epidemic in the UK have shown considerable uncertainty, with wide confidence bounds. However, recent vCJD case data have indicated a decrease in the annual incidence of deaths over the past two years. METHODS A detailed survival model is fitted to the 121 vCJD deaths reported by the end of 2002 stratified by age and calendar time to obtain projections of future incidence. The model is additionally fitted to recent results from a survey of appendix tissues. RESULTS Our results show a substantial decrease in the uncertainty of the future course of the primary epidemic in the susceptible genotype (MM-homozygous at codon 129 of the prion protein gene), with a best estimate of 40 future deaths (95% prediction interval 9-540) based on fitting to the vCJD case data alone. Additional fitting of the appendix data increases these estimates (best estimate 100, 95% prediction interval 10-2,600) but remains lower than previous projections. CONCLUSIONS The primary vCJD epidemic in the known susceptible genotype in the UK appears to be in decline.
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Affiliation(s)
- Azra C Ghani
- Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College of Science, Technology and Medicine, Norfolk Place, London W2 1PG, UK
| | - Christl A Donnelly
- Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College of Science, Technology and Medicine, Norfolk Place, London W2 1PG, UK
| | - Neil M Ferguson
- Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College of Science, Technology and Medicine, Norfolk Place, London W2 1PG, UK
| | - Roy M Anderson
- Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College of Science, Technology and Medicine, Norfolk Place, London W2 1PG, UK
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33
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Ghani AC, Ferguson NM, Donnelly CA, Anderson RM. Factors determining the pattern of the variant Creutzfeldt-Jakob disease (vCJD) epidemic in the UK. Proc Biol Sci 2003; 270:689-98. [PMID: 12713742 PMCID: PMC1691299 DOI: 10.1098/rspb.2002.2313] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Following the emergence of a new variant of Creutzfeldt-Jakob disease (vCJD) 6 years ago, and the gradual rise in clinical cases, there has been increased speculation regarding the overall magnitude of this epidemic in Great Britain. In this paper, we explore the epidemiological factors and uncertainties determining the scale of this epidemic in light of the most recent data on reported vCJD mortality. Our results demonstrate that, while the magnitude of the uncertainty has decreased dramatically since 1996, it is still not possible to predict with any degree of accuracy the final magnitude of this epidemic, with the 95% confidence interval for future cases being from 10 to 7000 deaths. However, short-term projections show that it is unlikely that a dramatic increase in case numbers will be observed in the next 2-5 years (95% confidence interval for 2 years: 10-80 cases, for 5 years: 10-200 cases). The results confirm significant age-dependent susceptibility/exposure to infection, with the likelihood profile demonstrating that those aged between 10 and 20 years are at highest risk of infection. We also demonstrate how projections based on onset data may be substantially biased, and explore the sensitivity of results to assumptions concerning the exposure to bovine spongiform encephalopathy (BSE) and the incubation-period distribution.
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Affiliation(s)
- Azra C Ghani
- Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College, Norfolk Place, London W2 1PG, UK.
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Abstract
Prion diseases are incurable neurodegenerative conditions affecting both animals and humans. They may be sporadic, infectious, or inherited in origin. Human prion diseases include Creutzfeldt-Jakob desease (CJD), Gerstmann-Straussler-Scheinker disease, kuru, and fatal familial insomnia. The appearance of variant CJD, and the demonstration that is caused by strains indistinguishable from bovine spongiform encephalopathy (BSE) in cattle, has led to the threat of a major epidemic of human prion disease in the UK and other countries where widespread dietary exposure to bovine prions has occurred. This article reviews the history and epidemiology of these diseases, and then focuses on important areas of current research in human prion disorders.
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Affiliation(s)
- Edward McKintosh
- Department of Neurodegenerative Disease/MRC Prion Unit, Institute of Neurology, University College London, London, United Kingdom
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35
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Donnelly CA, Ferguson NM, Ghani AC, Anderson RM. Implications of BSE infection screening data for the scale of the British BSE epidemic and current European infection levels. Proc Biol Sci 2002; 269:2179-90. [PMID: 12427310 PMCID: PMC1691156 DOI: 10.1098/rspb.2002.2156] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The incidence of confirmed clinical cases of bovine spongiform encephalopathy (BSE) in Great Britain continues to decline, but the recent discovery of cases in previously unaffected countries (including Israel, Japan, Poland, Slovenia and Spain) has heightened concerns that BSE transmission was more intense and widespread than previously thought. We use back-calculation methods to undertake an integrated analysis of data on infection prevalence in apparently healthy cattle and the incidence of confirmed clinical disease. The results indicate substantial underascertainment of clinical cases over the course of the British epidemic, and consequently that two- to fourfold more animals were infected than previously estimated. Upper bounds on the predicted size of the new variant Creutzfeldt-Jakob Disease (vCJD) epidemic are unaffected, as the prediction methods employed fit to observed vCJD mortality data, and are not sensitive to estimates of the absolute magnitude of past human exposure to BSE-infected cattle, only to relative changes in exposure through time. We also estimate the per-head incidence of infection in cattle born between 1993 and 1997 in other European Union countries, using data on the testing of apparently healthy cattle slaughtered for consumption. Infection incidence for cattle born after mid-1996 was highest in Greece, Italy and Belgium, with Spain and The Netherlands having intermediate levels, and estimates for Great Britain, Germany and France being comparably low.
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Affiliation(s)
- Christl A Donnelly
- Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College of Science, Technology and Medicine, St Mary's Campus, Norfolk Place, London W2 1PG, UK.
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36
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Macalister GO, Buckley RJ. The risk of transmission of variant Creutzfeldt–Jakob disease via contact lenses and ophthalmic devices. Cont Lens Anterior Eye 2002; 25:104-36. [PMID: 16303485 DOI: 10.1016/s1367-0484(02)00008-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This review collated the available information regarding the risk of transmission of variant Creutzfeldt-Jakob disease (vCJD) via contact lenses and other ophthalmic devices. The topics examined include: the emerging background science of the unconventional infective agent, the prion, particularly those factors affecting transmission; the estimates of the number of undiagnosed infective individuals; and evidence of infectivity in the external eye. Despite many uncertainties in the literature, we conclude that cross-infection is theoretically possible. An assessment of the extensive search for a complete inactivation procedure resulted in the recommendation of the use of sodium hypochlorite (NaOCl), which does not appear to distort rigid lenses. Further tests are required for other devices.
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Affiliation(s)
- Graham O Macalister
- Department of Optometry and Visual Science, City University, Northampton Square, London EC1V OHB, UK
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37
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Toxicology in Foods. FOOD SCIENCE AND TECHNOLOGY 2002. [DOI: 10.1201/9780203908969.pt2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Forloni G, Iussich S, Awan T, Colombo L, Angeretti N, Girola L, Bertani I, Poli G, Caramelli M, Grazia Bruzzone M, Farina L, Limido L, Rossi G, Giaccone G, Ironside JW, Bugiani O, Salmona M, Tagliavini F. Tetracyclines affect prion infectivity. Proc Natl Acad Sci U S A 2002; 99:10849-54. [PMID: 12149459 PMCID: PMC125061 DOI: 10.1073/pnas.162195499] [Citation(s) in RCA: 159] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Prion diseases are transmissible neurodegenerative disorders of humans and animals for which no effective treatment is available. Conformationally altered, protease-resistant forms of the prion protein (PrP) termed PrP(Sc) are critical for disease transmissibility and pathogenesis, thus representing a primary target for therapeutic strategies. Based on previous findings that tetracyclines revert abnormal physicochemical properties and abolish neurotoxicity of PrP peptides in vitro, we tested the ability of these compounds to interact with PrP(Sc) from patients with the new variant of Creutzfeldt-Jakob disease (vCJD) and cattle with bovine spongiform encephalopathy (BSE). The incubation with tetracycline hydrochloride or doxycycline hyclate at concentrations ranging from 10 microM to 1 mM resulted in a dose-dependent decrease in protease resistance of PrP(Sc). This finding prompted us to investigate whether tetracyclines affect prion infectivity by using an animal model of disease. Syrian hamsters were injected intracerebrally with 263K scrapie-infected brain homogenate that was coincubated with 1 mM tetracycline hydrochloride, 1 mM doxycycline hyclate, or vehicle solution before inoculation. Hamsters injected with tetracycline-treated inoculum showed a significant delay in the onset of clinical signs of disease and prolonged survival time. These effects were paralleled by a delay in the appearance of magnetic-resonance abnormalities in the thalamus, neuropathological changes, and PrP(Sc) accumulation. When tetracycline was preincubated with highly diluted scrapie-infected inoculum, one third of hamsters did not develop disease. Our data suggest that these well characterized antibiotics reduce prion infectivity through a direct interaction with PrP(Sc) and are potentially useful for inactivation of BSE- or vCJD-contaminated products and prevention strategies.
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Affiliation(s)
- Gianluigi Forloni
- Istituto di Ricerche Farmacologiche Mario Negri, Istituto Nazionale Neurologico Carlo Besta, and Istituto di Microbiologia e Immunologia Veterinaria, Università degli Studi, 20100 Milano, Italy
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Abstract
Attention throughout Europe continues to focus on bovine spongiform encephalopathy (BSE) with increasing evidence linking it to the new variant of Creutzfeldt-Jakob disease (vCJD) in humans. The age- and cohort-specific incidence of BSE in French cattle was modelled as a function of the survival distribution, the cohort-specific incidence of BSE infection, the underreporting rate of BSE cases, and the age-specific probability, conditional on survival, that an infected animal would experience clinical onset. The results reveal that thousands of French cattle were infected with BSE over the course of the epidemic. However, case incidence is predicted to decline in future years.
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Affiliation(s)
- Christl A Donnelly
- Department of Infectious Disease Epidemiology, Division of Primary Care and Population Health Sciences, Faculty of Medicine, Imperial College, Norfolk Place, London W2 1PG, United Kingdom.
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40
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Abstract
Variant Creutzfeldt-Jakob disease is one of a family of neurodegenerative diseases, first diagnosed in 1996. Scientific evidence strongly supports the hypothesis that it is acquired through consumption of bovine spongiform encephalopathy-infected meat. The majority of cases have been diagnosed in the UK in young individuals, with an excess of cases in the north and a significant cluster of cases in Leicestershire. Many uncertainties in its biology and epidemiology, in particular the length of the incubation period, make predictions of any future epidemic difficult. Studies are currently under way to obtain more precise estimates of the prevalence of asymptomatic infection through testing tonsil and appendix tissues for the abnormal prion protein.
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Affiliation(s)
- Azra C Ghani
- Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College of Science, Technology and Medicine, Norfolk Place, London, W2 1PG, UK.
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41
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Abstract
Prion disease in man was first described as Creutzfeldt-Jacob disease (CJD) in the 1920s. CJD may have three different origins: sporadic, familial, due to mutations in the prion gene, or infectious, due to iatrogenic exposure to infectious brain material. As an example of the latter, kuru, in Papua New Guinea, was a variant of CJD transmitted by cannibalism. Between 1957 and 1982 more than 2500 died of kuru. Sporadic CJD is the most common form of CJD and occurs with an incidence of around one per million in most parts of the world. Familial CJD accounts for approximately 10% of all European cases of CJD, and is associated with inherited mutations of the prion protein gene, caused by one of the 24 single amino acid substitutions or insertions of octapeptide repeats. CJD caused by infections involves either iatrogenic cases of CJD, resulting from exposure to infectious brain, pituitary or ocular tissue, or from ingestion of infected food items. As of today, a few hundred iatrogenic cases of CJD have been diagnosed worldwide, the majority due to transmission by cadaveric pituitary HCG. So far, 111 cases of vCJD have been diagnosed caused by BSE-contaminated food. The size of the epidemic is still unclear and worst-case scenarios indicate that we may expect many thousands of cases in the future.
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Abstract
The bovine spongiform encephalopathy (BSE) epidemic in cattle has had a huge economic impact on the agricultural industries across Europe. Furthermore, scientific evidence now strongly supporting a link between a new variant of Creutzfeldt-Jakob disease (vCJD) and consumption of BSE-infected animals has further heightened the need both to understand the transmission of these new diseases and to improve control measures to protect public health. In this paper we review work undertaken by our group using epidemiological models to understand the transmission dynamics of BSE and vCJD. We present new estimates of the future number of cases of BSE and the number of infected animals slaughtered for consumption for Great Britain, and summarise similar analyses undertaken for Northern Ireland, Ireland, Portugal and France. We also consider the epidemiological determinants of the future course of the vCJD epidemic, including the age and genetic characteristics of the confirmed cases, and present predictions of future case numbers.
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Affiliation(s)
- Azra C Ghani
- Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College of Science, Technology and Medicine (St Mary's), Norfolk Place, London W2 1PG, UK.
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Gill DS, Tredwin CJ, Gill SK, Ironside JW. The transmissible spongiform encephalopathies (prion diseases): a review for dental surgeons. Int Dent J 2001; 51:439-46. [PMID: 11789711 DOI: 10.1002/j.1875-595x.2001.tb00857.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The transmissible spongiform encephalopathies (prion diseases) are a fatal group of neurological diseases characterised by the accumulation of an abnormal form of prion protein in the brain. In humans, these disorders occur in sporadic, acquired and familial forms. Outbreaks of bovine spongiform encephalopathy, predominantly in the United Kingdom, and the emergence of a clinically and pathologically distinct human prion disease, variant CJD, has generated much interest in the transmissible spongiform encephalopathies. As the agent is detectable in lymphoid and neural tissue in variant CJD, clinicians should be aware of the possibility of cross infection of the causative agent. This is particularly important because the abnormal prion protein is resistant to routine sterilisation procedures. This article reviews the transmissible spongiform encephalopathies, and summarises guidelines concerning prevention of crossinfection when treating patients with or at risk of developing prion disease.
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Affiliation(s)
- D S Gill
- Department of Orthodontics, Dental Institute, The Royal London Hospital, Whitechapel, UK.
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d'Aignaux JN, Cousens SN, Smith PG. Predictability of the UK variant Creutzfeldt-Jakob disease epidemic. Science 2001; 294:1729-31. [PMID: 11679631 DOI: 10.1126/science.1064748] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Back-calculation analysis of the variant Creutzfeldt-Jakob disease epidemic in the United Kingdom is used to estimate the number of infected individuals and future disease incidence. The model assumes a hazard of infection proportional to the incidence of bovine spongiform encephalopathy in the United Kingdom and accounts for precautionary control measures and very wide ranges of incubation periods. The model indicates that current case data are compatible with numbers of infections ranging from a few hundred to several millions. In the latter case, the model suggests that the mean incubation period must be well beyond the human life-span, resulting in disease epidemics of at most several thousand cases.
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Affiliation(s)
- J N d'Aignaux
- London School of Hygiene and Tropical Medicine, Infectious Disease Epidemiology Unit, Keppel Street, London WC1E 7HT, UK.
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Nunery WR. Risk of prion transmission with the use of xenografts and allografts in surgery. Ophthalmic Plast Reconstr Surg 2001; 17:389-94. [PMID: 11766016 DOI: 10.1097/00002341-200111000-00001] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
Prion diseases are transmissible neurodegenerative conditions that include Creutzfeldt-Jakob disease (CJD) in humans and bovine spongiform encephalopathy (BSE) and scrapie in animals. Prions appear to be composed principally or entirely of abnormal isoforms of a host-encoded glycoprotein, prion protein. Prion propagation involves recruitment of host cellular prion protein, composed primarily of alpha-helical structure, into a disease specific isoform rich in beta-sheet structure. The existence of multiple prion strains has been difficult to explain in terms of a protein-only infections agent, but recent studies suggest that strain specific phenotypes can be encoded by different prion protein conformations and glycosylation patterns. The ability of a protein to encode phenotypic information has important biological implications. The appearance of a novel human prion disease, variant CJD, and the clear experimental evidence that it is caused by exposure to BSE has highlighted the need to understand the molecular basis of prion propagation, pathogenesis, and the barriers limiting intermammalian transmission. It is unclear if a large epidemic of variant CJD will occur in the years ahead.
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Affiliation(s)
- J Collinge
- MRC Prion Unit and Department of Neurogenetics, Imperial College School of Medicine at St. Mary's, London, United Kingdom.
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47
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Coulthart MB, Cashman NR. Variant Creutzfeldt-Jakob disease: a summary of current scientific knowledge in relation to public health. CMAJ 2001; 165:51-8. [PMID: 11468957 PMCID: PMC81246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Abstract
The prion diseases pose unique scientific, medical, veterinary and regulatory challenges. Here, we summarize current information bearing on the natural history, pathobiology and epidemiology of these disorders and public policy responses to the potential threats to public health posed, particularly, by bovine spongiform encephalopathy and variant Creutzfeldt-Jakob disease (vCJD). Six years after the first case reports of vCJD, there is still no clear indication of the magnitude of the primary epidemic, or of the likelihood of lateral transmission of this untreatable disease by iatrogenic means, particularly by blood and blood products. However, the unsettling nature of the available evidence warrants prudence regarding public health policy and regulation, as well as a forward-looking approach to research.
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Affiliation(s)
- M B Coulthart
- National Laboratory for Host Genetics and Prion Diseases, Canadian Science Centre for Human and Animal Health, Health Canada, Winnipeg, Man.
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Pérez Vaquero MA, Basaldua MA, Ibarra A, Renovales A, Larrea A, Vesga MA. [The impact of the implementation of staying in the United Kingdom for six months or more as donor exclusion criteria on the donor base of the Basque Country]. Med Clin (Barc) 2001; 116:413-5. [PMID: 11333688 DOI: 10.1016/s0025-7753(01)71851-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND To reduce the risk of new variant Creutzfeldt-Jakob disease by blood products some countries exclude persons who have spent six months or more cumulatively in the United Kingdom as blood donors. METHOD We asked our donors about this selection criteria to evaluate the loss of blood donors and donations in case of implementation of this measure. RESULTS 11,681 donors and 1,648 refused persons were analyzed. 123 (1.05%) and 11 (0.66%) respectively fulfilled this criteria. CONCLUSIONS In case of implementation of this selection criteria 1% of blood donors and 1.77% blood donations would be lost.
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Brown P, Will RG, Bradley R, Asher DM, Detwiler L. Bovine spongiform encephalopathy and variant Creutzfeldt-Jakob disease: background, evolution, and current concerns. Emerg Infect Dis 2001; 7:6-16. [PMID: 11266289 PMCID: PMC2631690 DOI: 10.3201/eid0701.010102] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The epidemic of bovine spongiform encephalopathy (BSE) in the United Kingdom, which began in 1986 and has affected nearly 200,000 cattle, is waning to a conclusion, but leaves in its wake an outbreak of human Creutzfeldt-Jakob disease, most probably resulting from the consumption of beef products contaminated by central nervous system tissue. Although averaging only 10-15 cases a year since its first appearance in 1994, its future magnitude and geographic distribution (in countries that have imported infected British cattle or cattle products, or have endogenous BSE) cannot yet be predicted. The possibility that large numbers of apparently healthy persons might be incubating the disease raises concerns about iatrogenic transmissions through instrumentation (surgery and medical diagnostic procedures) and blood and organ donations. Government agencies in many countries continue to implement new measures to minimize this risk.
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Affiliation(s)
- P Brown
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA.
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Abstract
Bovine spongiform encephalopathy (BSE) belongs to a group of progressively degenerative neurological diseases known as transmissible spongiform encephalopathies (TSEs) associated with a variant form of Creutzfeldt-Jakob disease in humans. TSEs are fatal diseases caused by prions (proteinaceous infectious particle) and are characterized by an incubation period that may range from several months to several years, depending on the host. Because BSE is spread through animal feed, the main strategy for preventing the establishment and spread of BSE is to prohibit the use of proteins derived from mammalian tissue in feed for ruminant animals. Enforcement of these regulations relies on the ability to identify the presence of prohibited proteins in ruminant feed. The methods to detect bovine products in rendered and cooked materials are based on analyses of DNA, bone, or protein. In this article, we discuss the current methodology as well as other potentially useful methods of analysis of animal material in food. While methods are generally useful, none specifically distinguish between prohibited bovine material and allowable bovine products, such as milk or blood. Furthermore, all these methods are hampered by the fact that the rendering process involves heat treatment that denatures and degrades proteins and DNA. There is a need for improving existing methods and developing new methods to overcome these two limitations.
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Affiliation(s)
- D Momcilovic
- Center of Veterinary Medicine, U.S. Food and Drug Administration, Rockville, Maryland, USA
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