Insights into the management of emerging infections: regulating variant Creutzfeldt-Jakob disease transfusion risk in the UK and the US

Prevention of transfusion-transmitted infections

Since the 1970s, introduction of serological assays targeting virus-specific antibodies and antigens has been effective in identifying blood donations infected with the classic transfusion-transmitted infectious agents (TTIs; hepatitis B virus [HBV], HIV, human T-cell lymphotropic virus types I and II, hepatitis C virus [HCV]). Subsequently, progressive implementation of nucleic acid-amplification technology (NAT) screening for HIV, HCV, and HBV has reduced the residual risk of infectious-window-period donations, such that per unit risks are <1 in 1 000 000 in the United States, other high-income countries, and in high-incidence regions performing NAT. NAT screening has emerged as the preferred option for detection of newer TTIs including West Nile virus, Zika virus (ZIKV), and Babesia microti Although there is continual need to monitor current risks due to established TTI, ongoing challenges in blood safety relate primarily to surveillance for emerging agents coupled with development of rapid response mechanisms when such agents are identified. Recent progress in development and implementation of pathogen-reduction technologies (PRTs) provide the opportunity for proactive rather than reactive response to blood-safety threats. Risk-based decision-making tools and cost-effectiveness models have proved useful to quantify infectious risks and place new interventions in context. However, as evidenced by the 2015 to 2017 ZIKV pandemic, a level of tolerable risk has yet to be defined in such a way that conflicting factors (eg, theoretical recipient risk, blood availability, cost, and commercial interests) can be reconciled. A unified approach to TTIs is needed, whereby novel tests and PRTs replace, rather than add to, existing interventions, thereby ameliorating cost and logistical burden to blood centers and hospitals.

Application of the analytic hierarchy process to a risk assessment of emerging infectious diseases in Shaoxing city in southern China

This study aimed to assess the likelihood of an outbreak or epidemic of emerging infectious diseases (EIDs) in Shaoxing city, China, and its resulting impact to provide decision makers with quantitative, directive results. Factors related to the risk of EIDs were selected through meeting with experts and were arranged in a hierarchical structure. These evaluation factors were also weighted to allow the use of a point system for evaluation. As a result, 14 evaluation factors comprising a 3-layer hierarchy were generated. The riskiest top 10 EIDs were HIV/AIDS (consistency index [CI] = 3.206), cholera (CI = 3.103), SARS (CI = 2.804), acute schistosomiasis (CI = 2.784), malaria (CI = 2.777), legionellosis (CI = 2.743), avian influenza A/H5N1 (CI = 2.734), dengue fever (CI = 2.702), Escherichia coli O157:H7 enteritis (CI = 2.593), and plague (CI = 2.553). The risk assessment was specifically intended to support local and national government agencies in the management of high risk EIDs in their efforts to (i) make resource allocation decisions, (ii) make high-level planning decisions, and (iii) raise public awareness of the EID risk. The results showed that the EID risk in Shaoxing could be effectively assessed through an analytic hierarchy process.

Prion diseases as transmissible zoonotic diseases

Prion diseases, also called transmissible spongiform encephalopathies (TSEs), lead to neurological dysfunction in animals and are fatal. Infectious prion proteins are causative agents of many mammalian TSEs, including scrapie (in sheep), chronic wasting disease (in deer and elk), bovine spongiform encephalopathy (BSE; in cattle), and Creutzfeldt-Jakob disease (CJD; in humans). BSE, better known as mad cow disease, is among the many recently discovered zoonotic diseases. BSE cases were first reported in the United Kingdom in 1986. Variant CJD (vCJD) is a disease that was first detected in 1996, which affects humans and is linked to the BSE epidemic in cattle. vCJD is presumed to be caused by consumption of contaminated meat and other food products derived from affected cattle. The BSE epidemic peaked in 1992 and decreased thereafter; this decline is continuing sharply owing to intensive surveillance and screening programs in the Western world. However, there are still new outbreaks and/or progression of prion diseases, including atypical BSE, and iatrogenic CJD and vCJD via organ transplantation and blood transfusion. This paper summarizes studies on prions, particularly on prion molecular mechanisms, BSE, vCJD, and diagnostic procedures. Risk perception and communication policies of the European Union for the prevention of prion diseases are also addressed to provide recommendations for appropriate government policies in Korea.

Notification and support for people exposed to the risk of Creutzfeldt-Jakob disease (CJD) (or other prion diseases) through medical treatment (iatrogenically)

BACKGROUND

Creutzfeldt-Jakob disease (CJD) and variant CJD (vCJD) are rare and always-fatal diseases transmissible via certain medical procedures. If a person is exposed to the disease risk through medical treatment, they may need to be notified of this to prevent them passing the risk to others in healthcare settings and to enable additional infection control measures to be put in place for certain procedures. As CJD is incurable, and unable to be screened for or effectively treated, communicating this risk information after an exposure incident may have significant implications for the person at risk, their families/ carers and healthcare professionals. The best ways to notify people of their exposure to the risk of CJD or vCJD, and to support them subsequently, are currently unknown.

OBJECTIVES

To evaluate the effects of interventions to notify and support consumers (patients and their family members or carers) in situations where exposure to the risk of CJD or vCJD has occurred as a result of medical treatment (iatrogenically), on consumer, healthcare provider and healthcare system outcomes.

SEARCH STRATEGY

We searched the Cochrane Consumers and Communication Review Group Specialised Register (10 February, 2009), the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1 2009), MEDLINE (OVID SP), EMBASE (OVID SP), PsycINFO (OVID SP), CINAHL (EBSCO Host), Current Contents (OVID SP) and Dissertation Abstracts (Proquest) from start date to February 2009. We searched MEDLINE In-process and Other Non-indexed Citations (OVID SP) and Sociological Abstracts (CSA) in November 2009. We searched reference lists, websites, and contacted consumer groups and experts for details of relevant research.

SELECTION CRITERIA

Randomised and quasi-randomised controlled studies, controlled before-and-after studies and interrupted time series analyses assessing the effects of any intervention to communicate with (notify or support) people exposed to the risk of CJD or vCJD through medical treatment were included. We sought outcomes relevant to consumers, health providers and health services, including both benefits and harms.

DATA COLLECTION AND ANALYSIS

Cochrane reviewTwo authors independently assessed studies for inclusion against selection criteria, and would have applied standard Cochrane review methodology were any studies identified.Thematic synthesisWe also conducted a thematic synthesis by systematically identifying and screening those studies that met the same population, intervention and outcome criteria as the Cochrane review, but that were identified from the broader literature providing evidence on policy implementation and consumer experiences. We systematically extracted and synthesised the data from these studies to produce a thematic synthesis, presented in appendices to this Cochrane review, which assembles evidence on the views, experiences and acceptability of notification and support strategies for people at risk.

MAIN RESULTS

Results of the Cochrane reviewNo studies meeting the study design criteria were identified for inclusion in this Cochrane review.Results of thematic synthesisIn total, 49 studies and pieces of literature meeting the same population, intervention and outcome criteria as the Cochrane review, but identified from the broader literature providing evidence on policy implementation and consumer experiences, were included and formed the basis of a thematic synthesis, and which is presented in appendices to this Cochrane review. The thematic synthesis indicates that ideally communication may be considered as a longitudinal multicomponent programme, ensuring that notification and support are coordinated; that communication is tailored and responsive to need; and that activities to support individual risk communication, such as widespread education and monitoring of access to health care for those at risk, are in place. The thematic synthesis also indicates that poor communication practices may have negative impacts or cause harm, such as discrimination in accessing health care.

AUTHORS' CONCLUSIONS

There is insufficient rigorous evidence to determine the effects of interventions to notify people at CJD or vCJD risk and to support them subsequently, or to identify the best approach to communication in these situations. The thematic synthesis can be used to inform policy and practice decisions for communicating with people at risk in the absence of rigorous evaluative studies.

Terminal ileal photography or biopsy to verify total colonoscopy: does the endoscope agree with the microscope?

BACKGROUND

Various modalities exist to document the extent of colonoscopy, including a terminal ileum (TI) biopsy, which is considered the criterion standard by some authorities. A TI biopsy adds to procedure costs, is potentially hazardous, and the detection of pathology in routinely acquired biopsy specimens of a macroscopically normal TI is limited. A safer, less costly alternative for documenting total colonoscopy is desirable.

OBJECTIVE

To evaluate the effectiveness of TI photography as a means of documenting total colonoscopy. We also assessed the diagnostic yield of TI biopsies in patients with a macroscopically normal TI.

DESIGN

Prospective, observational study.

SETTING

District general hospital in the United Kingdom.

PATIENTS

A total of 232 unselected patients undergoing colonoscopy, TI intubation, photography, and biopsy.

MAIN OUTCOME MEASUREMENTS

Independent, experienced endoscopists were asked to state whether villi (and, therefore, TI entry) were "definitely," "probably," or "definitely not" depicted in TI photographs. This was compared with TI histology as a means of verifying total colonoscopy. The diagnostic yield of biopsy specimens from a macroscopically normal TI was determined.

RESULTS

Reviewers agreed that villi were "definitely present" in 93.8%, "probably present" in 5.9%, and "definitely not" present in 0.3% of cases, with excellent interobserver agreement (kappa value = 0.778, P < .0001). TI photographs "definitely" depicting villi (93.8%) did not differ significantly from histology confirming TI mucosa (96.1%, P = .285). Microscopic evidence of pathology was only detectable in 2.3% of patients with an endoscopically normal TI.

CONCLUSIONS

TI photography is an effective, safe, and cost-effective means of documenting total colonoscopy. Routine biopsy of a "normal" TI has a low diagnostic yield.