Lessons from the West Nile viral encephalitis outbreak in New York City, 1999: implications for bioterrorism preparedness

Development and evaluation of an easy to use real-time reverse-transcription loop-mediated isothermal amplification assay for clinical diagnosis of West Nile virus

West Nile Virus (WNV) causes a serious public health concern in many countries around the world. Virus detection in pathological samples is a key component of WNV infection diagnostic, classically performed by real-time PCR. In outbreak situation, rapid detection of the virus, in peripheral laboratories or at point of care, is crucial to guide decision makers and for the establishment of adequate action plans to prevent virus dissemination. Here, we evaluate a Loop-mediated isothermal amplification (LAMP) tool for WNV detection. Amplifications were performed comparatively on extracted viral RNA and on crude samples using a classical thermal cycler and a portable device (pebble device). qRT-PCR was used as gold standard and two sets of urine samples (n = 62 and n = 74) were used to evaluate the retained amplification protocols and assess their sensitivity and specificity. RT-LAMP on RNA extracts and crude samples showed a sensitivity of 90 % and 87 %, respectively. The specificity was 100 % for extracts and 97 % for crude samples. Using the device, the RT-LAMP on extracted RNA was comparable to the gold standard results (100 % sensitivity and specificity) and it was a bit lower on crude samples (65 % sensitivity and 94 % specificity). These results show that RT-LAMP is an efficient technique to detect WNV. RT-LAMP provides a rapid, sensitive, high-throughput and portable tool for accurate WNV detection and has potentials to facilitate diagnostic and surveillance efforts both in the laboratory and in the field, especially in developing countries.

STING is required for host defense against neuropathological West Nile virus infection

West Nile Virus (WNV), an emerging and re-emerging RNA virus, is the leading source of arboviral encephalitic morbidity and mortality in the United States. WNV infections are acutely controlled by innate immunity in peripheral tissues outside of the central nervous system (CNS) but WNV can evade the actions of interferon (IFN) to facilitate CNS invasion, causing encephalitis, encephalomyelitis, and death. Recent studies indicate that STimulator of INterferon Gene (STING), canonically known for initiating a type I IFN production and innate immune response to cytosolic DNA, is required for host defense against neurotropic RNA viruses. We evaluated the role of STING in host defense to control WNV infection and pathology in a murine model of infection. When challenged with WNV, STING knock out (-/-) mice displayed increased morbidity and mortality compared to wild type (WT) mice. Virologic analysis and assessment of STING activation revealed that STING signaling was not required for control of WNV in the spleen nor was WNV sufficient to mediate canonical STING activation in vitro. However, STING-/- mice exhibited a clear trend of increased viral load and virus dissemination in the CNS. We found that STING-/- mice exhibited increased and prolonged neurological signs compared to WT mice. Pathological examination revealed increased lesions, mononuclear cellular infiltration and neuronal death in the CNS of STING-/- mice, with sustained pathology after viral clearance. We found that STING was required in bone marrow derived macrophages for early control of WNV replication and innate immune activation. In vivo, STING-/- mice developed an aberrant T cell response in both the spleen and brain during WNV infection that linked with increased and sustained CNS pathology compared to WT mice. Our findings demonstrate that STING plays a critical role in immune programming for the control of neurotropic WNV infection and CNS disease.

Beyond the Dirty Dozen: A Proposed Methodology for Assessing Future Bioweapon Threats

Background

Defense policy planners and countermeasure developers are often faced with vexing problems involving the prioritization of resources and efforts. This is especially true in the area of Biodefense, where each new emerging infectious disease outbreak brings with it questions regarding the causative agent's potential for weaponization. Recent experience with West Nile Virus, Severe Acute Respiratory Syndrome, Monkeypox, and H1N1 Influenza highlights this problem. Appropriately, in each of these cases, the possibility of bioterrorism was raised, although each outbreak ultimately proved to have a natural origin. In fact, determining whether an outbreak has an unnatural origin can be quite difficult. Thus, the questions remain: could the causative agents of these and other emerging infectious disease outbreaks pose a future weaponization threat? And how great is that threat? Should precious resources be diverted from other defense efforts in order to prepare for possible hostile employment of novel diseases by belligerents? Answering such critical questions requires some form of systematic threat assessment.

Methods

Through extensive collaborative work conducted within NATO's Biomedical Advisory Council, we developed a scoring matrix for evaluating the weaponization potential of the causative agents of such diseases and attempted to validate our matrix by examining the reproducibility of data using known threat agents. Our matrix included 12 attributes of a potential weapon and was provided, along with detailed scoring instructions, to 12 groups of biodefense experts in 6 NATO nations. Study participants were asked to score each of these 12 attributes on a scale of 0-3: Infectivity, Infection-to-Disease Ratio (Reliability), Predictability (& Incubation Period), Morbidity & Mortality (Virulence), Ease of Large-Scale Production & Storage, Aerosol Stability, Atmospheric Stability, Ease of Dispersal, Communicability, Prophylactic Countermeasure Availability, Therapeutic Countermeasure Availability, and Ease of Detection. Reproducibility of scoring data was assessed by examining the standard deviations (SD) of mean scores.

Results

Our results were unexpected. Several familiar biothreat diseases such as anthrax and tularemia were judged, by our experts, to be less threatening than many others owing to a number of factors including ease of detection, lack of communicability, and the ready availability of countermeasures. Conversely, several toxins were judged by experts to have very high potential as threat agents owing, in part, to their reliability, virulence, and a lack of available countermeasures. Agreement among experts, as determined by lower SD about a mean score, was greater for more familiar threats.

Discussion

Our study was designed to provide a concise and east-to-apply set of criteria that could be used by NATO nations to evaluate emerging infectious disease threats with respect to their weaponization potential. Our results were unexpected. We believe that a lack of appropriate weighting factors may explain these results and suggest that future studies weigh each of the 12 proposed criteria based on the intended use of the assessment data and other situational factors. We believe that the greatest value of our study lies in a codification of the attributes of a biological weapon.

An Overview of Zoonotic Disease Outbreaks and its Forensic Management Over Time

Most emerging or re-emerging infections are vector-borne or zoonotic and can be disseminated worldwide by infected humans or animals. They are a major public health problem and cause a great impact on economy. Zoonotic outbreaks began to be characterized in the 90s, after the creation of Europol and the FBI. Such investigations are carried by forensic pathologists and other specialists to determine whether an outbreak is natural or deliberate. This review will discuss ten zoonotic outbreaks nonrelated to wars focusing on forensic management. In conclusion, some points should be highlighted in the management of a zoonotic outbreak: (i) its diagnosis and detection by forensic pathologists and the coordination of efforts between other specialists are key factors; (ii) communication guidelines and an efficient healthcare system are crucial for any emergency response; (iii) biosafety of all specialists involved must be guaranteed.

Effective surveillance systems for vector-borne diseases in urban settings and translation of the data into action: a scoping review

Background

Vector-borne diseases (VBDs) continue to represent a global threat, with “old” diseases like malaria, and “emergent” or “re-emergent” ones like Zika, because of an increase in international trade, demographic growth, and rapid urbanization. In this era of globalization, surveillance is a key element in controlling VBDs in urban settings, but surveillance alone cannot solve the problem. A review of experiences is of interest to examine other solution elements. The objectives were to assess the different means of VBD surveillance in urban environments, to evaluate their potential for supporting public health actions, and to describe the tools used for public health actions, the constraints they face, and the research and health action gaps to be filled.

Main body

For this scoping review we searched peer-reviewed articles and grey literature published between 2000 and 2016. Various tools were used for data coding and extraction. A quality assessment was done for each study reviewed, and descriptive characteristics and data on implementation process and transferability were analyzed in all studies.

After screening 414 full-text articles, we retained a total of 79 articles for review. The main targets of the articles were arboviral diseases (65.8%) and malaria (16.5%). The positive aspects of many studies fit within the framework of integrated vector management. Public awareness is considered a key to successful vector control programs. Advocacy and legislation can reinforce both empowerment and capacity building. These can be achieved by collaboration within the health sector and with other sectors. Research is needed to develop well designed studies and new tools for surveillance and control.

Conclusions

The need for surveillance systems in urban settings in both developing and developed countries was highlighted. Countries face the same challenges relating to human, financial, and structural resources. These findings also constitute a wake-up call for governments, academia, funders, and World Health Organization to strengthen control programs and enhance VBD research in urban environments.

Electronic supplementary material

The online version of this article (10.1186/s40249-018-0473-9) contains supplementary material, which is available to authorized users.

Applying the One Health Concept to Mycobacterial Research - Overcoming Parochialism

Mycobacterial infections remain a public health problem. Historically important, globally ubiquitous and with a wide host range, we are still struggling to control mycobacterial infections in humans and animals. While previous reviews have focused on individual mycobacterial infections in either humans or animals, a comprehensive review of the zoonotic aspect of mycobacteria in the context of the One Health initiative is lacking. With the purpose of providing a concise and comprehensive resource, we have collated literature to address the zoonotic potential of different mycobacterial species and elaborate on the necessity for an inter-sectorial approach to attain a new vision to combat mycobacterial infections.

Thermally multiplexed polymerase chain reaction

Amplification of multiple unique genetic targets using the polymerase chain reaction (PCR) is commonly required in molecular biology laboratories. Such reactions are typically performed either serially or by multiplex PCR. Serial reactions are time consuming, and multiplex PCR, while powerful and widely used, can be prone to amplification bias, PCR drift, and primer-primer interactions. We present a new thermocycling method, termed thermal multiplexing, in which a single heat source is uniformly distributed and selectively modulated for independent temperature control of an array of PCR reactions. Thermal multiplexing allows amplification of multiple targets simultaneously-each reaction segregated and performed at optimal conditions. We demonstrate the method using a microfluidic system consisting of an infrared laser thermocycler, a polymer microchip featuring 1 μl, oil-encapsulated reactions, and closed-loop pulse-width modulation control. Heat transfer modeling is used to characterize thermal performance limitations of the system. We validate the model and perform two reactions simultaneously with widely varying annealing temperatures (48 °C and 68 °C), demonstrating excellent amplification. In addition, to demonstrate microfluidic infrared PCR using clinical specimens, we successfully amplified and detected both influenza A and B from human nasopharyngeal swabs. Thermal multiplexing is scalable and applicable to challenges such as pathogen detection where patients presenting non-specific symptoms need to be efficiently screened across a viral or bacterial panel.

A New Method of Differentiation Between a Biological Attack and Other Epidemics

The main obstacle in identifying a biological attack (BA), while preventing false alarms, epidemics of panic and unnecessary expenditures is the insufficient data on which to rely. Тhis new method of outbreak analysis is based on our original model of bioterrorism risk assessment. The intention was to develop a model of quick and accurate evaluation of an unusual epidemiologic event (UEE) that would save time, money, human and material resources and reduce confusion and panic. This UEE analysis is a subtle and detailed differentiation through assessment of BA feasibility in comparison with three other types of outbreak scenarios. There are two types of differences between these four scenarios: qualitative and quantitative. Qualitative and quantitative differences are defined with 23 and 10 indicators, respectively. Both types of indicators can have three different values: N/A, 0 or 1. We have carried out a feasibility analysis for subtle and detailed differentiation among four outbreak scenarios. As a tool for feasibility analysis we have introduced a “system of elimination”. System elimination is applied if one component contains all indicators scored with 0 or as N/A – the related scenario is then eliminated from further consideration. The system was applied to four UEEs: (1) an intentional attack by a deliberate use of a biological agent (Amerithrax), (2) a spontaneous outbreak of a new or re-emerging disease (“swine flu”), (3) a spontaneous outbreak by an accidental release of a pathogen (Sverdlovsk anthrax), and (4) a spontaneous natural outbreak of a known endemic disease that may mimic bioterrorism or biowarfare (Kosovo tularemia). It was found that “agent” was the most important and the most informative UEE component of the new scoring system. This system might be helpful in the analysis of unusual epidemic events and a quick differentiation between biological attacks and other epidemics.

Swine flu. Mexico's handling of A/H1N1 in comparative perspective

Emerging infectious diseases (EIDs) pose international security threats because of their potential to inflict harm upon humans, crops, livestock, health infrastructure, and economies. Despite the scale of this threat, there are inherent limitations in preventing and controlling EIDs, including the scope of current disease surveillance efforts. All of this leads to the following questions in the context of Mexico's recent swine flu experience: What were the cultural, political, and economic challenges to Influenza A/H1N1 virus response in Mexico? By way of comparison, what can we learn from the U.S. experience in 1976 with A/New Jersey/76 (Hsw1N1), later referred to as H1N1? This article explores the comparative political economy of Mexico's handling of influenza virus A/H1N1 outbreak in 2009. Research provides notable observations-based on the strengths and weaknesses of each country's response--that can be used as a starting point of discussion for the design of effective EIDs surveillance programs in developing and middle-income countries. In the U.S., the speed and efficiency of the 1976 U.S. mobilization against H1N1 was laudable. Although the U.S. response to the outbreak is seldom praised, the unity of the scientific and political communities demonstrated the national ability to respond to the situation. Mexico's strongest characteristics were its transparency, as well as the cooperation the country exhibited with other nations, particularly the U.S. and Canada. While Mexico showed savvy in its effective management of public and media relations, as the article details, political, economic, and cultural problems persisted.

Communicating emerging infectious disease outbreaks to the public through local television news: public health officials as potential spokespeople

OBJECTIVE

To assess how West Nile virus (WNV) was reported to the American public on local television news and identify the main factors that influenced coverage.

METHODS

A representative sample of WNV stories that were reported on 122 local television news stations across the United States during October 2002, covering 67% of the nation's population, were coded for self-efficacy, comparative risk scenarios, symptoms and recommendations, high-risk individuals, and frame. In addition, public service professionals (PSPs) interviewed in the segments were identified. Comparisons were made between stories in which a PSP was interviewed and stories without an interview with respect to discussion of the 5 variables coded.

RESULTS

Of the 1,371 health-related stories captured during the study period, 160 WNV stories aired, the second most common health topic reported. Forty-nine of the 160 WNV stories contained at least 1 of the 5 reporting variables. Forty-two PSPs were interviewed within 33 unique WNV stories. Public health officials composed 81% of all PSP interviews. Stories containing a public health official interview had 15.2 times (odds ratio 15.2, confidence interval 5.1-45.9) higher odds of reporting quality information, controlling for station affiliate or geographic location.

CONCLUSIONS

Emerging infectious disease stories are prominently reported by local television news. Stories containing interviews with public health officials were also much more likely to report quality information. Optimizing the interactions between and availability of public health officials and the local news media may enhance disaster communication of emerging infections.

Urgent care providers' knowledge and attitude about public health reporting and pertussis control measures: implications for informatics

OBJECTIVES

We assessed urgent care providers' knowledge about public health reporting, guidelines, and actions for the prevention and control of pertussis; attitudes about public health reporting and population-based data; and perception of reporting practices in their clinic.

METHODS

We identified the 106 providers (95% are physicians) employed in 28 urgent care clinics owned by Intermountain Healthcare located throughout Utah and Southern Idaho. We performed a descriptive, cross-sectional survey and assessed providers' knowledge, attitudes, beliefs, and behaviors associated with population-based data and public health mandates and recommendations. The online survey was completed between November 1, 2007, and February 29, 2008.

RESULTS

Among 63 practicing urgent care providers (60% response rate), 19 percent knew that clinically diagnosed pertussis was reportable, and only half (52%) the providers correctly responded about current pertussis vaccination recommendations. Most (35%-78%) providers did not know the prevention and control measures performed by public health practitioners after reporting occurs, including contact tracing, testing, treatment, and prophylaxis. Half (48%) the providers did not know that health department personnel can prescribe antibiotics for contacts of a reported case, and only 22 percent knew that health department personnel may perform diagnostic testing on contacts. Attitudes about reporting are variable, and reporting responsibility is diffused.

CONCLUSION

To improve our ability to meet public health goals, systems need to be designed that engage urgent care providers in the public health process, improve their knowledge and attitude about reporting, and facilitate the flow of information between urgent care and public health settings.

Agriculture emergencies: a primer for first responders

Over the past several years, the primary focus of emergency preparedness has been on terrorism, and how a CBRNE event would directly affect human health. Limited emphasis has been placed on the direct (eg, zoonotic infections) and indirect (eg, mental health, financial loss) effects that an agricultural emergency event can have on human health outcomes, and how they relate to emergency preparedness. We critically reviewed the resources and information readily accessible to our target audience, emergency responders; the resources included military and civilian books, personal communications, internet sites, GAO reports, and peer-reviewed journals. Among more than 2,000 bioterrorism-related articles, we found 51 that addressed either agroterrorism and/or veterinary public health: 2 cross-sectional studies, 28 review papers, and 21 commentary papers. In order to properly respond to future agriculture emergencies, emergency response professionals need to understand the nature and implications of the event as well as their roles and responsibilities, but the availability of educational and training opportunities is limited. The results of our review are consistent with the hypothesis that more resources, education, and training opportunities should be available to responders as well as to producers, importers and shippers, international travelers, and the general public. Increased education and training will raise awareness among these groups of the relationship between animal and human health.

An intervention to improve notifiable disease reporting using ambulatory clinics

Strong notifiable disease surveillance systems are essential for disease control. We sought to determine if a brief informational session between clinic and health department employees followed by reminder faxes and a newsletter would improve reporting rates and timeliness in a notifiable disease surveillance system. Ambulatory clinics were randomized to an intervention group which received the informational session, a faxed reporting reminder and newsletter, or to a control group. Among intervention and control clinics, there were improvements in the number of cases reported and the timeliness of reporting. However, there were no statistically significant changes in either group. Despite improved communication between the health department and clinics, this intervention did not significantly improve the level or the timeliness of reporting. Other types of interventions should be considered to improve reporting such as simplifying the reporting process.

A comparison of the completeness and timeliness of automated electronic laboratory reporting and spontaneous reporting of notifiable conditions

OBJECTIVES

We examined whether automated electronic laboratory reporting of notifiable-diseases results in information being delivered to public health departments more completely and quickly than is the case with spontaneous, paper-based reporting.

METHODS

We used data from a local public health department, hospital infection control departments, and a community-wide health information exchange to identify all potential cases of notifiable conditions that occurred in Marion County, Ind, during the first quarter of 2001. We compared traditional spontaneous reporting to the health department with automated electronic laboratory reporting through the health information exchange.

RESULTS

After reports obtained using the 2 methods had been matched, there were 4785 unique reports for 53 different conditions during the study period. Chlamydia was the most common condition, followed by hepatitis B, hepatitis C, and gonorrhea. Automated electronic laboratory reporting identified 4.4 times as many cases as traditional spontaneous, paper-based methods and identified those cases 7.9 days earlier than spontaneous reporting.

CONCLUSIONS

Automated electronic laboratory reporting improves the completeness and timeliness of disease surveillance, which will enhance public health awareness and reporting efficiency.

Discernment between deliberate and natural infectious disease outbreaks

Public health authorities should be vigilant to the potential for outbreaks deliberately caused by biological agents (bioterrorism). Such events require a rapid response and incorporation of non-traditional partners for disease investigation and outbreak control. The astute application of infectious disease epidemiological principles can promote an enhanced index of suspicion for such events. We discuss epidemiological indicators that should be considered during outbreak investigations, and also examine their application during bioterrorism incidents, an accidental release of an agent, outbreaks of infections that were alleged to have been deliberately initiated, and a model scenario. The Grunow & Finke epidemiological assessment tool is used to examine these historical events and the model scenario. The results received from this analysis, coupled with an understanding of epidemiological clues to unnatural events, and knowledge of how to manage such events, can aid in the improved response and resolution of epidemics.

Role of the microbiology laboratory in infectious disease surveillance, alert and response

Surveillance is usually defined as the ongoing and systematic collection, analysis and interpretation of health data essential to the planning, implementation and evaluation of public health practice. During recent years, most of these programmes have been developed in the field of antimicrobial resistance and nosocomial infections, but efforts have also been made in other areas. Recent experiences of emerging microbial threats, including severe acute respiratory syndrome and new influenza variants affecting humans, the re-emergence of infectious disease problems and the possibility of bioterrorism have evidenced the need for implementation of infectious disease surveillance programmes. Clinical microbiology laboratories play a pivotal role in these programmes. They have the first opportunity to detect these problems and should participate in the design of reporting strategies and dissemination of this information. Policies for the flow of data to national and international authorities should be established using passive surveillance strategies. However, active surveillance programmes taking advantage of new methodologies, including virtual tools and mathematical programs, should be the goal for early detection of unusual patterns of microbial pathogens, outbreaks and healthcare-associated infections. In addition, early implementation of response strategies should be designed and performed with the cooperation of microbiology laboratories, and intervention and response protocols should be defined with the participation of clinical microbiologists.

[Emerging or re-emerging infections that can be used for bioterrorism]

USED FOR WARFARE: Bioterrorism is a perfectly foreseeable eventuality. It is defined by the international use, or menace of use, of living organisms whatever their nature, or of substances derived from these organisms, aimed at provoking a disease or the death of human beings, animals or plants. UPDATED COUNTERACTING STRATEGIES: More than 180 infectious agents could be used for terrorist ends. The recent events in the dawn of this twenty-first century have reactivated and notably updated the strategies to counteract such an event. Clinical and therapeutic guidelines have been circulated in many countries. INFECTIONS THAT REQUIRE RECOGNITION: The role of practitioners in the rapid recognition of bioterrorism-related infections is crucial. Hence, updated knowledge on these potentially emerging or reemerging infections is required.

Patients' request for and emergency physicians' prescription of antimicrobial prophylaxis for anthrax during the 2001 bioterrorism-related outbreak

Background

Inappropriate use of antibiotics by individuals worried about biological agent exposures during bioterrorism events is an important public health concern. However, little is documented about the extent to which individuals with self-identified risk of anthrax exposure approached physicians for antimicrobial prophylaxis during the 2001 bioterrorism attacks in the United States.

Methods

We conducted a telephone survey of randomly selected members of the Pennsylvania Chapter of the American College of Emergency Physicians to assess patients' request for and emergency physicians' prescription of antimicrobial agents during the 2001 anthrax attacks.

Results

Ninety-seven physicians completed the survey. Sixty-four (66%) respondents had received requests from patients for anthrax prophylaxis; 16 (25%) of these physicians prescribed antibiotics to a total of 23 patients. Ten physicians prescribed ciprofloxacin while 8 physicians prescribed doxycycline.

Conclusion

During the 2001 bioterrorist attacks, the majority of the emergency physicians we surveyed encountered patients who requested anthrax prophylaxis. Public fears may lead to a high demand for antibiotic prophylaxis during bioterrorism events. Elucidation of the relationship between public health response to outbreaks and outcomes would yield insights to ease burden on frontline clinicians and guide strategies to control inappropriate antibiotic allocation during bioterrorist events.

Les virus des encéphalites virales, une nouvelle menace bioterroriste

Often responsible for little known infections, today viral encephalitis viruses appear as a new bioterrorist menace, because of their easy production and their great pathogenic potential. Spraying is the best way to permit the rapid diffusion of certain encephalitis viruses. Diagnosis of viral encephalitis, predominating in tropical surroundings, is difficult. In the majority of cases, symptoms differ little from those of common flu. With supplementary examinations, the biological abnormalities are usually non-specific. There are no characteristic images on scans or MRI. Identification of the virus in the nasopharynx, blood or cerebrospinal fluid, in serology, PCR or RT-PCR permits confirmation of the virus. Treatment is essentially symptomatic and relies on appropriate reanimation measures. Ribavirin can be indicated in some cases such as the Rift Valley fever, but is formally contraindicated in West Nile encephalitis. The aim of terrorist groups who would use this type of weapon is more to provoke panic and disorganisation than to kill as many people as possible.

Epidemic West Nile virus encephalitis in Tunisia

West Nile fever (WNF) is a mosquito-borne flavivirus infection. It is epidemic in Africa and Asia. In autumn 1997, a WNF epidemic occurred in the Sfax area (southeastern Tunisia). Fifty-seven patients were hospitalized with aseptic meningitis and/or encephalitis. Search for specific anti-West Nile virus (WNV) antibodies in serum and cerebrospinal fluid (CSF) was performed using an ELISA test. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to detect the WNV genome in CSF and brain specimens. Recent central nervous system (CNS) infection by WNV was confirmed in 30 patients, probable infection in 17 and it was excluded in 10. In the confirmed subgroup, patients with encephalitis were older than those with meningitis. CSF showed pleocytosis, high protein (47%) and normal glucose levels. Brain computed tomography-scan (CT-scan) and magnetic resonance imaging (MRI) were normal. RT-PCR disclosed WNV genome in the CSF in two cases and in a brain specimen in one. Three patients died rapidly, the remaining cases had favorable prognosis. Autopsy was performed in two cases and showed nonspecific lesions of encephalitis. No viral inclusions were seen with light microscopy. Seropositivity rate in patients' proxies for WNV was 23.4%. Prognosis of CNS involvement during WNF seemed to be poor in older patients. This is the first WNV encephalitis epidemic report in the Sfax area of Tunisia.

Representative threats for research in public health surveillance

A large number of biological agents can cause natural or bioterroristic disease outbreaks and each can present in a bewildering number of ways (e.g., a few cases versus many cases, confined to a building versus widely disseminated). This 'problem space' is a challenge for designers of early warning systems for disease outbreaks and the sheer size of this space is a barrier to progress. This paper addresses this problem by deriving nine categories of threats that represent a parsimonious characterization of the problem space. A literature search also identified one or more example outbreaks for each of the nine categories. These outbreaks have occurred in recent times and could be used by researchers in need of actual outbreak data for investigations of the role of different types of surveillance data and algorithms in outbreak detection. The methodological contribution of this research is a Criterion Set of threats for analysis and evaluation of detection systems. This set characterizes the problem space in a tractable manner with less loss of generality than analyses based on one or two selected diseases, which is representative of current analyses.

Crimean-Congo Hemorrhagic Fever: Prevention and Control Limitations in a Resource-Poor Country

In autumn 2000, an outbreak of Crimean-Congo hemorrhagic fever (CCHF) occurred in Pakistan and involved nosocomial cases due to human-to-human transmission at a tertiary care hospital in Karachi. During a hospital-based investigation, 6 serologically confirmed cases (i.e., patients seropositive for CCHF antigen or anti-CCHF immunoglobulin M antibodies by means of a capture enzyme-linked immunosorbent assay [ELISA]) and 3 clinically confirmed cases (i.e., patients with negative ELISA for CCHF but with relevant epidemiologic exposures and compatible clinical disease) of CCHF were identified. The outbreak originated in rural Balochistan, a region of known CCHF endemicity where miniepidemics regularly occur, and subsequently spread to the urban centers of Quetta and Karachi. This outbreak demonstrated the capacities and weaknesses associated with a developing country's response to hemorrhagic fever epidemics. We describe aspects of disease prevention, control challenges, and political obstacles posed by illness associated with what we refer to as the "Asian Ebola virus."

Herpes simplex encephalitis: an audit of the use of laboratory diagnostic tests

BACKGROUND

The combination of both PCR and intrathecal antibody studies is recommended to confirm or refute the diagnosis of herpes simplex encephalitis (HSE).

AIM

To investigate the pattern of use of laboratory tests in the diagnosis of suspected cases of HSE, and to determine the final diagnosis in cases proven not to be HSE.

DESIGN

Structured audit.

METHODS

We reviewed the case-notes of all patients who, over a five-year time period, presented with suspected encephalitis; and/or were prescribed aciclovir. Clinical and laboratory criteria were used to categorize the likelihood of HSE.

RESULTS

We identified 222 patients: 10 (5%) had definite HSE, 24 (10%) possible HSE, and 144 (65%) a definite alternative diagnosis. In 44 (20%), no final diagnosis was made, but the diagnosis of HSE was excluded. PCR was performed in 68 (31%), intrathecal antibody studies in 24 (11%), and brain biopsy in 17 (8%). A wide range of diseases mimicked HSE, but most common were inflammatory diseases and other infections of the central nervous system.

DISCUSSION

Laboratory tests, particularly intrathecal antibody assays, are under-used in the diagnosis of HSE. Although early empirical treatment of suspected HSE is essential, confirmation or exclusion of the diagnosis is equally important to avoid overlooking alternative diagnoses. Identification of the aetiology of encephalitis is of particular importance, given the current concerns of emerging infections and bioterrorism.

Automated laboratory reporting of infectious diseases in a climate of bioterrorism

While newly available electronic transmission methods can increase timeliness and completeness of infectious disease reports, limitations of this technology may unintentionally compromise detection of, and response to, bioterrorism and other outbreaks. We reviewed implementation experiences for five electronic laboratory systems and identified problems with data transmission, sensitivity, specificity, and user interpretation. The results suggest a need for backup transmission methods, validation, standards, preserving human judgment in the process, and provider and end-user involvement. As illustrated, challenges encountered in deployment of existing electronic laboratory reporting systems could guide further refinement and advances in infectious disease surveillance.

Early season crow mortality as a sentinel for West Nile virus disease in humans, northeastern United States

The 1999 New York epidemic of human West Nile virus (WN) encephalitis and meningitis was preceded by a crow die-off also caused by WN infection. As one component of the subsequently developed national surveillance system, crow mortality data were collected to detect WN activity before humans might become infected. However, predicting areas at risk for human WN disease likely requires assessment of multiple factors, including the intensity and timing of crow epizootics. To identify early season measures of WN activity in crows associated with subsequent WN disease in humans, county-level crow mortality data from seven northeastern states were analyzed. A predictive model was developed based on analysis of 2000 surveillance data and then assessed for 2001. To characterize the intensity of early season WN activity in crows, 15 variables were constructed from surveillance data of 52 counties that tested at least four crows during the early season (defined as June 17-July 28, 2000). County values for each variable were dichotomized at the 75th percentile into "high" and "low" activity. Multivariate analysis indicated that "high" early season activity of two variables-density of reported dead crow sightings (reported dead crows/area) and [(WN-infected crows/tested crows) x (human population)]--were associated with report of at least one human WN disease case (for each variable: adjusted odds ratio, 6.9; 95% confidence interval, 1.2-40.6). An assessment of this model using 2001 surveillance data from 61 counties yielded similar findings. With emphasis on early season WN activity, crow surveillance may allow timely targeting of interventions to protect the public health.

Emerging viral infections of the nervous system

New viral infections of the nervous system have been appearing with great regularity. Some result from the evolution of new agents and others from the entry of viruses into new hosts or environments. The emergence of neurovirulent enteroviruses causing a paralytic poliomyelitis syndrome and rhomboencephalitis represent the evolution of new human viruses. Most emerging viral infections represent movement of an agent into new geographic areas or across species barriers. The transport of neurovirulent strains of West Nile virus into the Western Hemisphere and the penetration of Nipah virus, a newly recognized paramyxovirus, across species barriers from bat to pig to man are examples that are highlighted in this review. The burgeoning human population and the speed and frequency of travel favor the evolution, preservation, and spread of new viral agents.

Meeting the challenge of bioterrorism: lessons learned from West Nile virus and anthrax

Hospital emergency departments (EDs) and ambulatory clinics may be the first to recognize illness related to a bioterrorist event. Every health-care institution must develop a weapons-of-mass- destruction (WMD) preparedness plan as part of its all-hazards disaster planning. As part of an all-hazards disaster plan, WMD preparedness should use the incident-command model to insure the required chain of command for effectively coordinating activities between hospital departments and external agencies. Preparedness for bioterrorism poses unique challenges. In the event of a biological attack, the hospital infection control staff and administration must already have in place the means to communicate with local and state public health agencies, the Centers for Disease Control and Prevention (CDC), local law-enforcement agencies, and the Federal Bureau of Investigation (FBI). Local and regional planners must consider how to coordinate the responses of emergency medical services (EMS), police, and fire departments with healthcare providers and the news media. Most hospitals are ill equipped to deal with a catastrophic event caused by WMD. The burden of responding to such events will fall initially on ED physicians and staff members. The severity of such an incident might be mitigated with careful planning, training and education. The responses of one hospital network to the outbreak of West Nile virus and, more recently, to the threat of anthrax, are presented as guides for bioterrorism preparedness.

West Nile virus encephalitis in the United States

West Nile virus appeared in New York City in 1999 and has subsequently spread over the eastern United States. The mode of transport across the Atlantic Ocean is unknown. During the past decade, encephalitis has been a more prominent feature of West Nile virus infection in Europe, the Middle East, and the United States, suggesting the emergence of more neurovirulent strains. The rapid spread of the virus and more serious disease caused by the virus have spurred vaccine development.

Laboratory response to anthrax bioterrorism, New York City, 2001

In October 2001, the greater New York City Metropolitan Area was the scene of a bioterrorism attack. The scale of the public response to this attack was not foreseen and threatened to overwhelm the Bioterrorism Response Laboratory's (BTRL) ability to process and test environmental samples. In a joint effort with the Centers for Disease Control and Prevention and the cooperation of the Department of Defense, a massive effort was launched to maintain and sustain the laboratory response and return test results in a timely fashion. This effort was largely successful. The development and expansion of the facility are described, as are the special needs of a BTRL. The establishment of a Laboratory Bioterrorism Command Center and protocols for sample intake, processing, reporting, security, testing, staffing, and and quality control are also described.

Surveillance for anthrax cases associated with contaminated letters, New Jersey, Delaware, and Pennsylvania, 2001

In October 2001, two inhalational anthrax and four cutaneous anthrax cases, resulting from the processing of Bacillus anthracis-containing envelopes at a New Jersey mail facility, were identified. Subsequently, we initiated stimulated passive hospital-based and enhanced passive surveillance for anthrax-compatible syndromes. From October 24 to December 17, 2001, hospitals reported 240,160 visits and 7,109 intensive-care unit admissions in the surveillance area (population 6.7 million persons). Following a change of reporting criteria on November 8, the average of possible inhalational anthrax reports decreased 83% from 18 to 3 per day; the proportion of reports requiring follow-up increased from 37% (105/286) to 41% (47/116). Clinical follow-up was conducted on 214 of 464 possible inhalational anthrax patients and 98 possible cutaneous anthrax patients; 49 had additional laboratory testing. No additional cases were identified. To verify the limited scope of the outbreak, surveillance was essential, though labor-intensive. The flexibility of the system allowed interim evaluation, thus improving surveillance efficiency.

Future challenges in preparing for and responding to bioterrorism events

The future success of our preparations for bioterrorism depends on many issues as presented in this article. If these issues are properly addressed, the resulting improvements in bioterrorism preparations will allow us to better deter and mitigate a bioterrorism incident and will also provide us with the added benefit of improvements in early detection, diagnosis, and treatment of natural disease outbreaks. Emergency physicians must take an active leading role in working with the various disciplines to produce a better-prepared community.

Bioterrorism preparedness. II: The community and emergency medical services systems

Disaster planning is an arduous task. Perhaps no form of disaster is more difficult to prepare for than one resulting from the intentional, covert release of a biological pathogen or toxin. The complexities of response operations and the perils of inadequate preparation cannot be overemphasized. Even with detailed planning, deviations from anticipated emergency operations plans are likely to occur. Several federal programs have been initiated to assist communities in enhancing their preparedness for events involving biological and other agents of mass destruction. Many of these, such as the Metropolitan Medical Response Systems (MMRS) Program [37,38], will be discussed elsewhere. Community preparedness will be enhanced by: 1. Implementing a real-time public health disease surveillance program linking local healthcare, emergency care, EMS, the CDC, local law enforcement, and the FBI 2. Improved real-time regional patient and healthcare capacity status management 3. Development of affordable, accurate biological agent detection systems 4. Incorporation of standardized education and training curricula (appropriate for audience) on terrorism and biological agents into healthcare training programs 5. Expansion of federal and state programs to assist communities in system development 6. Increased public awareness and education programs.

Diagnostic analyses of biological agent-caused syndromes: laboratory and technical assistance

The impact of a bioterrorism attack can be greatly reduced by collaboration among primary healthcare providers, laboratories, the veterinary community, public health officials, and emergency response personnel. Improved communication and coordination are essential to make this happen. As a first-line provider, the emergency physician must keep in mind the possibility of bioterrorism and alert the laboratory so that samples can be processed in the correct fashion. New and exciting developments in laboratory organization, communication, and diagnostic capabilities will ensure that all patients receive the best possible care.

Bioterrorism and the people: how to vaccinate a city against panic

Bioterrorism policy discussions and response planning efforts have tended to discount the capacity of the public to participate in the response to an act of bioterrorism, or they have assumed that local populations would impede an effective response. Fears of mass panic and social disorder underlie this bias. Although it is not known how the population will react to an unprecedented act of bioterrorism, experience with natural and technological disasters and disease outbreaks indicates a pattern of generally effective and adaptive collective action. Failure to involve the public as a key partner in the medical and public-health response could hamper effective management of an epidemic and increase the likelihood of social disruption. Ultimately, actions taken by nonprofessional individuals and groups could have the greatest influence on the outcome of a bioterrorism event. Five guidelines for integrating the public into bioterrorism response planning are proposed: (1) treat the public as a capable ally in the response to an epidemic, (2) enlist civic organizations in practical public health activities, (3) anticipate the need for home-based patient care and infection control, (4) invest in public outreach and communication strategies, and (5) ensure that planning reflects the values and priorities of affected populations.