Anthrax postexposure prophylaxis in postal workers, Connecticut, 2001

Outbreak of Anthrax in Livestock with Human Occupational Exposures - Minnesota, 2023

In July 2023, the Minnesota Department of Health (MDH) was notified of possible occupational exposures to anthrax during an outbreak in animals. In consultation with the Centers for Disease Control and Prevention, MDH epidemiologists created a questionnaire that assessed exposure risks and helped determine individual illness monitoring and antibiotic post-exposure prophylaxis needs. This investigation and the resources developed for it could be useful in future scenarios where there are occupational exposures to naturally occurring anthrax.

Development of a Pharmacy Point-of-Dispensing Toolkit for Anthrax Post-Exposure Prophylaxis for Allegheny County Postal Workers

CONTEXT

The Centers for Disease Control and Prevention (CDC) and the US Postal Service (USPS) consider anthrax to be a potential threat to USPS workers. A county health department-owned pharmacy supports local USPS response in the event of an exposure. The pharmacy team identified the need to review and update the local anthrax response plan.

PROGRAM/POLICY

A Pharmacy Point-of-Dispensing Toolkit and response plan for initial 10-day post-exposure antibiotic prophylaxis was developed for use by a local health department in the event of a mass anthrax exposure at a US Post Office sorting facility. The pharmacist's role in medical countermeasures planning for anthrax exposure is also discussed to illustrate how pharmacists' medication expertise can be utilized.

EVALUATION

The CDC's Public Health Preparedness Capabilities: National Standards for State and Local Planning framework and inputs from an interprofessional stakeholder team were used to develop a Medical Countermeasures Response Plan and Implementation Toolkit for mass point-of-dispensing (POD) in the event of an anthrax exposure.

IMPLEMENTATION AND DISSEMINATION

Stakeholders attended a USPS Community Partner Training event where additional revisions to the toolkit were made. The toolkit and standing order are now implemented at the local health department to be reviewed and updated on a yearly basis by health department leadership.

DISCUSSION

Pharmacists can use their medication expertise and experience with patient education to design emergency response plans focused on increasing patient safety and medication adherence. Pharmacists should be involved in emergency response and medical countermeasures planning that involve medications.

Anti-infective immunoadhesins from plants

Immunoadhesins are recombinant proteins that combine the ligand-binding region of a receptor or adhesion molecule with immunoglobulin constant domains. All FDA-approved immunoadhesins are designed to modulate the interaction of a human receptor with its normal ligand, such as Etanercept (Enbrel(®) ), which interferes with the binding of tumour necrosis factor (TNF) to the TNF-alpha receptor and is used to treat inflammatory diseases such as rheumatoid arthritis. Like antibodies, immunoadhesins have long circulating half-lives, are readily purified by affinity-based methods and have the avidity advantages conferred by bivalency. Immunoadhesins that incorporate normal cellular receptors for viruses or bacterial toxins hold great, but as yet unrealized, potential for treating infectious disease. As decoy receptors, immunoadhesins have potential advantages over pathogen-targeted monoclonal antibodies. Planet Biotechnology has specialized in developing anti-infective immunoadhesins using plant expression systems. An immunoadhesin incorporating the cellular receptor for anthrax toxin, CMG2, potently blocks toxin activity in vitro and protects animals against inhalational anthrax. An immunoadhesin based on the receptor for human rhinovirus, ICAM-1, potently blocks infection of human cells by one of the major causes of the common cold. An immunoadhesin targeting the MERS coronavirus is in an early stage of development. We describe here the unique challenges involved in designing and developing immunoadhesins targeting infectious diseases in the hope of inspiring further research into this promising class of drugs.

Monoclonal antibody therapies against anthrax

Anthrax is a highly lethal infectious disease caused by the spore-forming bacterium Bacillus anthracis. It not only causes natural infection in humans but also poses a great threat as an emerging bioterror agent. The lethality of anthrax is primarily attributed to the two major virulence factors: toxins and capsule. An extensive effort has been made to generate therapeutically useful monoclonal antibodies to each of the virulence components: protective antigen (PA), lethal factor (LF) and edema factor (EF), and the capsule of B. anthracis. This review summarizes the current status of anti-anthrax mAb development and argues for the potential therapeutic advantage of a cocktail of mAbs that recognize different epitopes or different virulence factors.

Public response to an anthrax attack: reactions to mass prophylaxis in a scenario involving inhalation anthrax from an unidentified source

An attack with Bacillus anthracis ("anthrax") is a known threat to the United States. When weaponized, it can cause inhalation anthrax, the deadliest form of the disease. Due to the rapid course of inhalation anthrax, delays in initiation of antibiotics may decrease survival chances. Because a rapid response would require cooperation from the public, there is a need to understand the public's response to possible mass dispensing programs. To examine the public's response to a mass prophylaxis program, this study used a nationally representative poll of 1,092 adults, supplemented by a targeted focus on 3 metropolitan areas where anthrax attacks occurred in 2001: New York City (n=517), Washington, DC (n=509), and Trenton/Mercer County, NJ (n=507). The poll was built around a "worst-case scenario" in which cases of inhalation anthrax are discovered without an identified source and the entire population of a city or town is asked to receive antibiotic prophylaxis within a 48-hour period. Findings from this poll provide important signs of public willingness to comply with public health recommendations for obtaining antibiotics from a dispensing site, although they also indicate that public health officials may face several challenges to compliance, including misinformation about the contagiousness of inhalation anthrax; fears about personal safety in crowds; distrust of government agencies to provide sufficient, safe, and effective medicine; and hesitation about ingesting antibiotic pills after receiving them. In general, people living in areas where anthrax attacks occurred in 2001 had responses similar to those of the nation as a whole.

Anti-toxin antibodies in prophylaxis and treatment of inhalation anthrax

The CDC recommend 60 days of oral antibiotics combined with a three-dose series of the anthrax vaccine for prophylaxis after potential exposure to aerosolized Bacillus anthracis spores. The anthrax vaccine is currently not licensed for anthrax postexposure prophylaxis and has to be made available under an Investigational New Drug protocol. Postexposure prophylaxis based on antibiotics can be problematic in cases where the use of antibiotics is contraindicated. Furthermore, there is a concern that an exposure could involve antibiotic-resistant strains of B. anthracis. Availability of alternate treatment modalities that are effective in prophylaxis of inhalation anthrax is therefore highly desirable. A major research focus toward this end has been on passive immunization using polyclonal and monoclonal antibodies against B. anthracis toxin components. Since 2001, significant progress has been made in isolation and commercial development of monoclonal and polyclonal antibodies that function as potent neutralizers of anthrax lethal toxin in both a prophylactic and therapeutic setting. Several new products have completed Phase I clinical trials and are slated for addition to the National Strategic Stockpile. These rapid advances were possible because of major funding made available by the US government through programs such as Bioshield and the Biomedical Advanced Research and Development Authority. Continued government funding is critical to support the development of a robust biodefense industry.

Human monoclonal antibody AVP-21D9 to protective antigen reduces dissemination of the Bacillus anthracis Ames strain from the lungs in a rabbit model

Dutch-belted and New Zealand White rabbits were passively immunized with AVP-21D9, a human monoclonal antibody to protective antigen (PA), at the time of Bacillus anthracis spore challenge using either nasal instillation or aerosol challenge techniques. AVP-21D9 (10 mg/kg) completely protected both rabbit strains against lethal infection with Bacillus anthracis Ames spores, regardless of the inoculation method. Further, all but one of the passively immunized animals (23/24) were completely resistant to rechallenge with spores by either respiratory challenge method at 5 weeks after primary challenge. Analysis of the sera at 5 weeks after primary challenge showed that residual human anti-PA levels decreased by 85 to 95%, but low titers of rabbit-specific anti-PA titers were also measured. Both sources of anti-PA could have contributed to protection from rechallenge. In a subsequent study, bacteriological and histopathology analyses revealed that B. anthracis disseminated to the bloodstream in some naïve animals as early as 24 h postchallenge and increased in frequency with time. AVP-21D9 significantly reduced the dissemination of the bacteria to the bloodstream and to various organs following infection. Examination of tissue sections from infected control animals, stained with hematoxylin-eosin and the Gram stain, showed edema and/or hemorrhage in the lungs and the presence of bacteria in mediastinal lymph nodes, with necrosis and inflammation. Tissue sections from infected rabbits dosed with AVP-21D9 appeared comparable to corresponding tissues from uninfected animals despite lethal challenge with B. anthracis Ames spores. Concomitant treatment with AVP-21D9 at the time of challenge conferred complete protection in the rabbit inhalation anthrax model. Early treatment increased the efficacy progressively and in a dose-dependent manner. Thus, AVP-21D9 could offer an adjunct or alternative clinical treatment regimen against inhalation anthrax.

The cost-effectiveness of strategies to reduce mortality from an intentional release of aerosolized anthrax spores

BACKGROUND

Intentional exposures to aerosolized Bacillus anthracis spores have caused fatalities.

OBJECTIVE

To evaluate the cost-effectiveness of strategies to reduce mortality from future inhalational anthrax exposures.

METHODS

Computer cohort simulation of a 100,000-person single-site exposure (worst-case scenario) and a 100-person multiple-site exposure (resembling the recent US attack). For each scenario, universal vaccination and an emergency surveillance and response (ESR) system were compared with a default strategy that assumed eventual discovery of the exposure.

RESULTS

If an exposure was unlikely to occur or was small in scale, neither vaccination nor an ESR system was cost-effective. If an exposure was certain and large in scale, an ESR system was more cost-effective than vaccination ($73 v. $29,600 per life-year saved), and a rapid response saved more lives than improved surveillance.

CONCLUSIONS

Strategies to reduce deaths from anthrax attacks are cost-effective only if large exposures are certain. A faster response is more beneficial than enhanced surveillance.

Antibiotic selection and resistance issues with fluoroquinolones and doxycycline against bioterrorism agents

Bacillus anthracis (anthrax), Yersinia pestis (plague), Francisella tularensis (tularemia), Coxiella burnetti (Q fever), and Brucella sp (brucellosis) are all potential bioterrorism agents. Their known virulence, potential lethality, and ability to develop resistance to known antibiotic treatments make these pathogens particularly dangerous. We reviewed the scientific literature by searching MEDLINE databases and published abstracts from the Interscience Conference on Antimicrobial Agents and Chemotherapy and the Infectious Diseases Society of America from 1989-2005 for studies of each of these biologic agents with the specific aim of examining whether doxycycline or a fluoroquinolone should be stockpiled for mass-scale postexposure prophylaxis. An evidence-based approach was used to determine whether doxycycline or fluoroquinolones were efficacious (both in vitro and in vivo) against these biologic agents and to examine these drugs' respective susceptibility patterns and differences in cost, based on available data. Little published data are available on these pathogens, and much of the data are from studies that used older strains obtained from patient or animal sources in outbreaks decades ago. Doxycycline appears to show comparable minimum inhibitory concentrations to those of the fluoroquinolone class in most clinical and in vitro studies, perhaps with the exception of inhalation plague. Studies also suggest that development of antibiotic resistance is less likely to occur with doxycycline. Doxycycline is several-fold less expensive than most fluoroquinolones and appears to have similar efficacy in most scenarios based on clinical case studies and established Clinical and Laboratory Standards Institute (formerly known as the National Committee for Clinical Laboratory Standards) breakpoints for staphylococci. Therefore, doxycycline should be considered as a first-line antibiotic in the management of bioterrorism agents.

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.

Threat: a concept analysis for a new era

TOPIC

Living in a post-September 11 world, the concept of threat has never been more apparent in people's minds.

PURPOSE

To reviews past analyses, capture the critical elements, and clarify a newly defined meaning of threat.

SOURCES

Walker and Avant's method was used to conduct the analysis.

CONCLUSIONS

Understanding an individual's perceived threat and the emotions experienced by this phenomenon can help develop research-based interventions, decrease perceived threat, increase positive coping strategies, and decrease negative emotions.

Is it influenza or anthrax? A decision analytic approach to the treatment of patients with influenza-like illnesses

STUDY OBJECTIVE

We analyze the risks and benefits of alternative treatment strategies for non-septic-appearing febrile patients with influenza-like illnesses and possible exposure to anthrax.

METHODS

We used a decision analytic model to evaluate 6 testing and treatment strategies in an emergency department. Patients were non-septic-appearing and had influenza-like illnesses but low likelihood of exposure to anthrax. The following interventions were used: (1) no empiric antibiotics; (2) blood culture and treatment only if the result was positive; (3) rapid testing for influenza and, for those who tested negative, treatment with 60 days of ciprofloxacin; (4) a two-test strategy in which all patients were first tested for influenza; those who tested negative had a blood culture test and were treated empirically with ciprofloxacin for 3 days while waiting for blood culture results; (5) culture test for all patients and treatment with ciprofloxacin for up to 3 days while waiting for blood culture results; and (6) treatment of all patients with ciprofloxacin empirically for 60 days. Main outcome measures were deaths, complications from anthrax, adverse events from ciprofloxacin, and ciprofloxacin patient-days.

RESULTS

For nonzero probabilities of anthrax, patient mortality was always lowest in the strategies in which all patients were treated empirically for anthrax either for 60 days or for 3 days pending blood culture results. These strategies, however, were associated with more morbidity (more ciprofloxacin patient-days and more antibiotic adverse events) than were strategies without empiric treatment. The numbers of adverse events and antibiotic patient-days were reduced substantially with the two-test strategy, in which patients with influenza were identified early and not treated. In general, for probabilities of anthrax equaling or exceeding 2%, treating all patients empirically for 60 days was best, but for probabilities between 0.1% and 2%, the sensitivity of blood culture for anthrax determined the optimal strategy: when the sensitivity exceeded 95%, a short course of empiric ciprofloxacin until blood culture results became available was best, but for sensitivities below 95%, more aggressive empiric antibiotics use was warranted. The proportion of patients with influenza in the community affected the choice of strategy, so that seasonal variation exists.

CONCLUSION

During influenza season, our findings support rapid testing for influenza, followed by empiric treatment for anthrax pending blood culture results for those who test negative for influenza. Our results help to highlight the importance of developing rapid and sensitive tests for anthrax and of developing improved surveillance and methods to calculate the previous probability of attacks.

Emergency response to an anthrax attack

We developed a mathematical model to compare various emergency responses in the event of an airborne anthrax attack. The system consists of an atmospheric dispersion model, an age-dependent dose-response model, a disease progression model, and a set of spatially distributed two-stage queueing systems consisting of antibiotic distribution and hospital care. Our results underscore the need for the extremely aggressive and timely use of oral antibiotics by all asymptomatics in the exposure region, distributed either preattack or by nonprofessionals postattack, and the creation of surge capacity for supportive hospital care via expanded training of nonemergency care workers at the local level and the use of federal and military resources and nationwide medical volunteers. The use of prioritization (based on disease stage andor age) at both queues, and the development and deployment of modestly rapid and sensitive biosensors, while helpful, produce only second-order improvements.

Investigation of bioterrorism-related anthrax, United States, 2001: epidemiologic findings

In October 2001, the first inhalational anthrax case in the United States since 1976 was identified in a media company worker in Florida. A national investigation was initiated to identify additional cases and determine possible exposures to Bacillus anthracis. Surveillance was enhanced through health-care facilities, laboratories, and other means to identify cases, which were defined as clinically compatible illness with laboratory-confirmed B. anthracis infection. From October 4 to November 20, 2001, 22 cases of anthrax (11 inhalational, 11 cutaneous) were identified; 5 of the inhalational cases were fatal. Twenty (91%) case-patients were either mail handlers or were exposed to worksites where contaminated mail was processed or received. B. anthracis isolates from four powder-containing envelopes, 17 specimens from patients, and 106 environmental samples were indistinguishable by molecular subtyping. Illness and death occurred not only at targeted worksites, but also along the path of mail and in other settings. Continued vigilance for cases is needed among health-care providers and members of the public health and law enforcement communities.