Bioterrorism-related inhalational anthrax in an elderly woman, Connecticut, 2001

Drumming-associated anthrax incidents: exposures to low levels of indoor environmental contamination

Two fatal drumming-related inhalational anthrax incidents occurred in 2006 and 2008 in the UK. One individual was a drum maker and drummer from the Scottish Borders, most likely infected whilst playing a goat-skin drum contaminated with Bacillus anthracis spores; the second, a drummer and drum maker from East London, likely became infected whilst working with contaminated animal hides.

We have collated epidemiological and environmental data from these incidents and reviewed them alongside three similar contemporaneous incidents in the USA. Sampling operations recovered the causative agent from drums and drum skins and from residences and communal buildings at low levels. From these data, we have considered the nature of the exposures and the number of other individuals likely to have been exposed, either to the primary infection events or to subsequent prolonged environmental contamination (or both).

Despite many individual exposures to widespread low-level spore contamination in private residences and in work spaces for extended periods of time (at least 1 year in one instance), only one other individual acquired an infection (cutaneous). Whilst recognising the difficulty in making definitive inferences from these incidents to specific residual contamination levels, and by extending the risk to public health, we believe it may be useful to reflect on these findings when considering future incident management risk assessments and decisions in similar incidents that result in low-level indoor contamination.

Unexplained Deaths in Connecticut, 2002–2003:Failure to Consider Category A Bioterrorism Agents in Differential Diagnoses

Background: Recognition of bioterrorism-related infections by hospital and emergency department clinicians may be the first line of defense in a bioterrorist attack.

Methods: We identified unexplained infectious deaths consistent with the clinical presentation of anthrax, tularemia, smallpox, and botulism using Connecticut death certificates and hospital chart information. Minimum work-up criteria were established to assess the completeness of diagnostic testing.

Results: Of 4558 unexplained infectious deaths, 133 were consistent with anthrax (2.9%) and 6 (0.13%) with tularemia. None were consistent with smallpox or botulism. No deaths had anthrax or tularemia listed in the differential diagnosis or had disease-specific serology performed. Minimum work-up criteria were met for only 53% of cases.

Conclusions: Except for anthrax, few unexplained deaths in Connecticut could possibly be the result of the bioterrorism agents studied. In 47% of deaths from illnesses that could be anthrax, the diagnosis would likely have been missed. As of 2004, Connecticut physicians were not well prepared to intentionally or incidentally diagnose initial cases of anthrax or tularemia. More effective clinician education and surveillance strategies are needed to minimize the potential to miss initial cases in a bioterrorism attack. (Disaster Med Public Health Preparedness. 2008;2:87–94)

Evaluation of applicability of the Sartorius Airport MD8 sampler for detection of Bacillus endospores in indoor air

This study was designed to evaluate the measuring range and lowest limit of detection of Bacillus endospores in the ambient room air when the Sartorius MD8 sampler, and two different culture methods for bacterial enumeration were used. Different concentrations of bioaerosol were generated inside the test chamber filled with either the high-efficiency particulate air (HEPA)-filtered air or with the ambient room air. The detection of endospores in the HEPA-filtered air was achievable: (1) when they were aerosolized at a concentration above 7.56 × 10(3) CFU/m(3) and analyzed with spread plate method, and (2) when they were aerosolized at a concentration above 4.00 × 10(2) CFU/m(3) and analyzed with pour plate method. The detection of endospores in the ambient room air was possible: (1) when they were aerosolized at a concentration above 9.1 × 10(3) CFU/m(3) and analyzed with spread plate method, and (2) when they were aerosolized at a concentration above 5.6 × 10(2) CFU/m(3) and analyzed with pour plate method. The microorganisms present in the ambient room air interfere with precise quantification of Bacillus endospores when their concentration is relatively low. The results of this study may be helpful in critical assessment of the results obtained from monitoring the air for bacterial endospores.

Evaluation of Gram-positive rod surveillance for early anthrax detection

Since 2003, Connecticut laboratories have reported Gram-positive rod (GPR) isolates detected within 32 h of inoculation from blood or cerebrospinal fluid. The objectives were to rapidly identify inhalational anthrax and unusual Clostridium spp. infections, and to establish round-the-clock laboratory reporting of potential indicators of bioterrorism. From 2003 to 2006, Connecticut's GPR surveillance system identified 1134 isolates, including 657 Bacillus spp. (none B. anthracis) and 241 Clostridium spp. Reporting completeness and timeliness improved to 93% and 92%, respectively. Baseline rates of Bacillus spp., Clostridium spp. and other GPR findings have been established and are stable. Thus far, no cases of anthrax and no unusual clusters of Clostridium spp. have been detected by the GPR surveillance system. This system would probably have confirmed the inhalational anthrax case in Pennsylvania in 2006 3 days sooner than traditional reporting. Using audits and ongoing evaluation, the system has evolved into a highly functional 24/7 laboratory telephone reporting system with almost complete reporting.

State-wide hospital clinical laboratory plan for measuring cholinesterase activity for individuals suspected of exposure to nerve agent chemical weapons

BACKGROUND

Hospital laboratories currently lack the capacity to provide emergency determination of cholinesterase activity.

METHODS

We have developed a hospital-based 3-tiered system to test plasma for butyrylcholinesterase (BChE) activity and whole blood for red cell acetylcholinesterase (AChE) activity using available technology and personnel. Interagency communications, toxidrome definition, and patient triage will be coordinated by the Connecticut Department of Public Health and the Poison Control Center.

DATA

Initial BChE data documents good precision between institutions (coefficient of variation < 8%).

SUMMARY

Laboratory testing of plasma or blood for cholinesterase activity is important in the management of nerve agent exposure and in ruling out disease in those with non-specific symptoms in the setting of a terrorist attack or accidental exposure. Rapid availability of strong hospital-based analytic support in a smoothly functioning network of clinical, public health, and laboratory services will facilitate overall regional response to chemical terrorism or large scale HazMat events.

Performance indicators for response to selected infectious disease outbreaks: a review of the published record

The purpose of this study was to determine whether published reports of infectious disease outbreaks could serve as a source of evidence for public health practice, particularly in responding to bioterrorism. Such performance indicators are measures of practice and process that lead to optimal health outcomes. We collected data from 116 individual articles that described 59 outbreaks of eight different pathogens with potential for bioterrorist use. Analysis of these reports determined whether they addressed 12 process indicators and four outcome indicators--each generally recognized as a component of effective outbreak response. The results showed that outbreak reports typically included information about these process and outcome indicators, thus validating their practical importance. However, few reports had been written with specificity to document the chronology of outbreak response, or the dissemination of information to protect healthcare workers, or the communication with law enforcement and emergency operations that are important in response to bioterrorism. We conclude that the published record of infectious disease outbreaks can, in the future, be used as a source for practice-based evidence if agreed-upon measures for effective performance become standard components of outbreak reports.

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.

Discriminating Inhalational Anthrax From Community-Acquired Pneumonia Using Chest Radiograph Findings and a Clinical Algorithm

BACKGROUND

Limiting the effects of a large-scale bioterrorist anthrax attack will require rapid and accurate detection of the earliest victims. We undertook this study to improve physicians' ability to rapidly detect inhalational anthrax victims.

METHODS

We conducted a case-control study to compare chest radiograph findings from 47 patients from historical inhalational anthrax cases and 188 community-acquired pneumonia control subjects. We then used classification tree analyses to derive an algorithm of chest radiograph findings and clinical characteristics that accurately and explicitly discriminated between inhalational anthrax and community-acquired pneumonia.

RESULTS

Twenty-two of the 47 patients from historical inhalational anthrax cases (46.8%) had reported chest radiograph findings. All 22 case patients (100%) had mediastinal widening, pleural effusion, or both. However, 16 case patients (72.7%) also had infiltrates. In comparison, all 188 community-acquired control subjects had reported chest radiographs. Of these, 127 control subjects (67.6%) had infiltrates, 43 control subjects (22.9%) had pleural effusions, and 15 control subjects (8.0%) had mediastinal widening. A derived algorithm with three predictor variables (chest radiograph finding of mediastinal widening, altered mental status, and elevated hematocrit) is 100% sensitive (95% confidence interval [CI], 73.5 to 100) and 98.3% specific (95% CI, 95.1 to 99.6). The derivation process used 12 patients with inhalational anthrax and 177 control subjects with community-acquired pneumonia who had information available for all three variables.

CONCLUSIONS

There are significant chest radiograph differences between inhalational anthrax and community-acquired pneumonia, but none of the chest radiograph findings are both highly sensitive and highly specific. The derived clinical algorithm can improve physicians' ability to discriminate inhalational anthrax from community-acquired pneumonia, but its utility is limited to previously healthy individuals and its accuracy may be limited by missing values.

Microneedle-based intradermal delivery of the anthrax recombinant protective antigen vaccine

The recombinant protective antigen (rPA) of Bacillus anthracis is a promising anthrax vaccine. We compared serum immunoglobulin G levels and toxin-neutralizing antibody titers in rabbits following delivery of various doses of vaccine by microneedle-based intradermal (i.d.) delivery or intramuscular (i.m.) injection using conventional needles. Intradermal delivery required less antigen to induce levels of antibody similar to those produced via i.m. injection during the first 2 weeks following primary and booster inoculation. This dose-sparing effect was less evident at the later stages of the immune response. Rabbits immunized i.d. with 10 mug of rPA displayed 100% protection from aerosol spore challenge, while i.m. injection of the same dose provided slightly lower protection (71%). Groups immunized with lower antigen doses were partially protected (13 to 29%) regardless of the mode of administration. Overall, our results suggest rPA formulated with aluminum adjuvant and administered to the skin by a microneedle-based device is as efficacious as i.m. vaccination.

Gram-positive rod surveillance for early anthrax detection

Connecticut established telephone-based gram-positive rod (GPR) reporting primarily to detect inhalational anthrax cases more quickly. From March to December 2003, annualized incidence of blood isolates was 21.3/100,000 persons; reports included 293 Corynebacterium spp., 193 Bacillus spp., 73 Clostridium spp., 26 Lactobacillus spp., and 49 other genera. Around-the-clock GPR reporting has described GPR epidemiology and enhanced rapid communication with clinical laboratories.

Evaluation of public health interventions for Anthrax: a report to the secretary's council on Public Health Preparedness

To aid in understanding how best to respond to a bioterror anthrax attack, we analyze a system of differential equations that includes a disease progression model, a set of spatially distributed queues for distributing antibiotics, and vaccination (pre-event and/or post-event). We derive approximate expressions for the number of casualties as a function of key parameters and management levers, including the time at which the attack is detected, the number of days to distribute antibiotics, the adherence to prophylactic antibiotics, and the fraction of the population that is preimmunized. We compare a variety of public health intervention policies in the event of a hypothetical anthrax attack in a large metropolitan area. Modeling assumptions were decided by the Anthrax Modeling Working Group of the Secretary's Council on Public Health Preparedness. Our results highlight the primary importance of rapid antibiotic distribution and lead us to argue for ensuring post-attack surge capacity to rapidly produce enough anthrax vaccine for an additional 100 million people.

Validation of a pXO2-A PCR assay to explore diversity among Italian isolates of Bacillus anthracis strains closely related to the live, attenuated Carbosap vaccine

Several circulating Bacillus anthracis strains isolated in Italy and belonging to the A1.a cluster, genotype 3 (A1.a-3) are genotypically indistinguishable from Carbosap, a live attenuated vaccine strain, containing both pXO1 and pXO2 plasmids. The genotype was assessed by using eight-locus multilocus variable-number tandem repeat analysis. We describe here the use of a ninth locus able to explore variability among strains that have the same genotype. It is important to be able to genotype the wild isolate of B. anthracis strains from outbreaks of anthrax in areas where Carbosap vaccination of cattle and sheep is common practice. A total of 27 representative field strains isolated in Italy and four vaccinal strains, namely, Carbosap, Sterne, Pasteur I, and Pasteur II, were characterized by a ninth marker, called pXO2-A. Twenty-three field strains were genotype 3 and therefore identical to Carbosap. The marker was in the pXO2 plasmid and is based on the polymorphism of the already-known VX2-3 locus. Detection was obtained by PCR with fluorescence-labeled forward primers in order to produce appropriate fragments for capillary electrophoresis with an ABI 310 genetic analyzer. Genetic relationships showed heterogeneity in all of the examined samples. Interestingly, with respect to genotype 3, samples grouped into eight different subtypes, A to H, and the subtype G, had only two samples indistinguishable from Carbosap. The results of the present study confirm the validity of a hierarchical progressive protocol for discrimination among closely related isolates.

Developing vaccines to counter bioterrorist threats

Large and innovative research programs are underway to define the immune parameters for vaccines against a wide array of pathogens considered to represent a potential bioterrorist threat. However, the development and utilization of such vaccines presents a number of predicaments that have not previously been addressed by the field of vaccinology.

A model curriculum for public health bioterrorism education

Beginning with the spring semester of 2001, a course designed to prepare future public health leaders for potential bioterrorism events has been offered by the University of Connecticut Graduate Program in Public Health. Entitled "The Public Health Response to Bioterrorism," this popular course was one of the few developed by academic programs in the United States prior to the attack of September 11, 2001. The course utilizes innovative teaching methods and presentations by distinguished guest speakers to educate public health personnel, public health and medical students, and physicians and nurses about the complex issues involved in the public health response to bioterrorism. The instructional methods and curriculum can serve as prototypes for similar efforts.

INFECTIOUS DISEASES

The emergence of new pathogens, or the concern about bioterrorism, has brought an added urgency to the development of more efficient and rapid methods to detect pathogens and predict their potential virulence. Till date, DNA testing in microbiology has been directed predominantly to the detection of organisms that are difficult to culture in vitro, or for various reasons the growth is unlikely. DNA analysis can be used successfully in infections in which there is a mix of pathogens. Apart from the straightforward diagnostic applications, DNA microbiological testing has been used to detect antimicrobial resistance or toxigenic forms of E. coli. More recently, the availability of DNA technology to quantitate HCV and HIV has been useful in planning and monitoring treatment. The pathogenesis of many infections, particularly viral ones, can also be realized from experimental strategies based on light and electron microscopy, cell culture and immunoassay. The advantages that are provided by DNA techniques include the ability to detect latent (non-replicating) viruses and to localize their genomes to nuclear or cytoplasmic regions within cells. Nucleic acid probe techniques (NAT) can also be manipulated to enable a broad spectrum of serotypes to be detectable. This is particularly valuable in those emerging infections where the underlying serotypes are unknown.

Isolated case of bioterrorism-related inhalational anthrax, New York City, 2001

On October 31, 2001, in New York City, a 61-year-old female hospital employee who had acquired inhalational anthrax died after a 6-day illness. To determine sources of exposure and identify additional persons at risk, the New York City Department of Health, Centers for Disease Control and Prevention, and law enforcement authorities conducted an extensive investigation, which included interviewing contacts, examining personal effects, summarizing patient's use of mass transit, conducting active case finding and surveillance near her residence and at her workplace, and collecting samples from co-workers and the environment. We cultured all specimens for Bacillus anthracis. We found no additional cases of cutaneous or inhalational anthrax. The route of exposure remains unknown. All environmental samples were negative for B. anthracis. This first case of inhalational anthrax during the 2001 outbreak with no apparent direct link to contaminated mail emphasizes the need for close coordination between public health and law enforcement agencies during bioterrorism-related investigations.