Strategies to Protect the Health of Deployed U.S. Forces Assessing Health Risks to Deployed U.S. Forces: Workshop Proceedings (2000) / Chapter Skim
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5 Future Health Assessment and Risk-Management Integration for Infectious Diseases and Biological Weapons for Deployed U.S. Forces
5 Future Health Assessment and Risk-Management Integration for Infectious Diseases and Biological Weapons for Deployed U.S. Forces
Pages 59-112
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From page 59... ...
New microorganisms are being reported every year that might be associated with many of these illnesses, and prospective surveillance might be needed using new techniques to better understand the infection rates and asymptomatic infections. Risk-assessment methods can now be used to quantify the risk of microbial infections and to address exposure and potential outcome from naturally occurring microorganisms and biological weapons.
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From page 60... ...
Finally, the formal expansion of DOD's mission on emerging infectious diseases in June 1996 by Presidential Decision Directive NSTC-7 now includes global surveillance, training, research, and response. One of the major assets in implementing this new directive is the overseas research laboratory system that is currently in place: the DOD Infectious Disease Research Laboratories.
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From page 61... ...
There is currently a greater appreciation of the diversity, adaptability, and evolutionary complexities associated with infectious diseases, and much of this appreciation has been gained through research and studies with new molecular techniques. The technological advances in the study of microbiology, infectious disease, and molecular biology have also paved the way for a potential increased risk associated with the development and use of biological weapons.
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From page 62... ...
The purpose of this report is to: · summarize the emerging infectious diseases and microbiological contaminant risks that U.S. deployed troops might face currently and in the future; · briefly examine the various health disease databases that are available; and · address quantitative research and data needs for integration of the microbial and biological risks into DOD risk-assessment and risk-management frameworks.
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From page 63... ...
Text Box 1, from the Memorandum for Under Secretary of Defense for Personnel and Readiness, Office of the Chairman, The Joint Chiefs of Staff, December 4, 1998, has the list of infectious agents that are reportable.
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From page 64... ...
However, no testing is undertaken routinely. It is generally accepted that surveillance systems greatly underestimate the level of disease in any given community and, although providing a picture of past risk, thus might not accurately reflect future risk.
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From page 65... ...
1. Excludes Helicobacter and most enteric viruses.
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From page 66... ...
. This outcome has also been related to reactions to immunizations (Medical Surveillance Monthly Report (MSMR)
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From page 67... ...
These data might be particularly misleading regarding the risk for deployed troops outside the United States. The completeness of reporting is dependent on the etiological agent; for example, for the two militarily important tropical infectious diseases, malaria and leishmaniasis, reporting was 67% and 81% complete.
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From page 68... ...
For those on active duty, coming from field sites, Adult Respiratory Distress Syndrome (ARDS) apparently is common.
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From page 69... ...
Although Escherichia cold and Shigella sonnet were the primary pathogens identified, of great concern was the high level of antibiotic resistance identified (20 to 80% of the isolates were resistant)
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From page 70... ...
A combined U.S.-Australian military operation in Queensland, Australia, in March 1997 exhibited the successful approach that is used by the military for control of vectorborne diseases (MSMR 1997~. Arboviruses were endemic to the region and the exercise corresponded to the seasonal peak of transmission of the Ross River virus (RRv)
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From page 71... ...
Emerging Infectious Agents Worldwide, the leading cause of death remains the variety of infectious diseases that plague human beings. In the United States, the risk of dying from an infectious disease rose from fifth place to third place just in the last decade due to emerging and reemerging microorganisms.
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From page 72... ...
Coxsackieviruses Encephalitis Aseptic meningitis Diarrhea Respiratory disease Heart disease (myocarditis) , reactive insulin-dependent diabetes Echoviruses Aseptic meningitis Source: CDC 1997.
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From page 73... ...
The coxsackieviruses now need to be considered separately as one of the enteroviruses that might be related to more significant risks (Bendinelli end Friedman 1988~. Diarrhea has been one of the risks associated with many of the enteric viruses such as Norwalk virus, but more serious chronic diseases have now been associated with viral infections and these risks need to be better defined.
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From page 74... ...
In North America, there have been 12 waterborne outbreaks of Cryptosporidium. It has also been associated with drinking water outbreaks in the United Kingdom, Japan, and Holland.
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From page 75... ...
The prevalence of microsporidiosis in studies of patients with chronic diarrhea ranges from 7 to 50% worldwide (Bryan 1995~. It is unclear whether this broad range represents geographic variation, differences in diagnostic capabilities, or differences in risk factors for exposure to microsporidia.
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From page 76... ...
The outbreak was attributed to a single drinking water source for the area. The number of newly identified cases of toxoplasmosis declined sharply after the drinking water reservoir suspected of contamination was shut down.
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From page 77... ...
cold strains under routine drinking water conditions. There have been two documented outbreaks of waterborne disease caused by E
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From page 78... ...
The health outcomes associated with Campylobacterassociated GBS have been estimated at <1% developing GBS, 20% of those requiring ventilation and 10% of those dying. Prions Prions are protein-based agents that are able to self-replicate and cause disease.
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From page 79... ...
The worldwide spread of the vectors, the difficulty in implementing control measures, and newly identified resistant strains are challenges that continue to present themselves to deployed troops. Table 9 summarizes some of the key vectorborne diseases.
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From page 80... ...
The severity of the disease is related to sequential infection by two serotypes (Halstead 1988~. Characteristics of this disease are high attack rates (70 to 80%)
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From page 81... ...
Biological Weapons Biological agents used as weapons will be spread through similar transmission routes as naturally occurring infectious agents. Fecal-oral microorganisms will likely be spread by contaminating the food or water supply.
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From page 82... ...
need to be considered. Multiple Exposure Issues In exposure assessment and dose-response modeling, single contaminant experiments and evaluations have been the primary focus of most studies.
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From page 83... ...
For example, it is now known that the coxsackieviruses are associated with various forms of heart disease, eye infections, and respiratory disease. Studies in mice have shown an increased virulence (severe outcomes)
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From page 84... ...
The disease surveillance that is currently in place can be used to examine these issues, but better exposure assessment must be undertaken. Animal models with experimentation associated with mixtures need to be developed, including mixtures of microorganisms with antibiotics, vaccinations, metals, and other infections.
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From page 85... ...
1 ANALYSTS PHASE I Exposure Analysis Pathogen Occurrence Exposure Profile Health Effects | Dose-Response| ,~ | Host Pathogen I Profile FIGURE 7 Analysis phase for microbial risk assessment (ILSI 1996~. Risk Assessment for Microorganisms Hazard Identification Hazard identification includes the identification of the microbial agent as well as the spectrum of human illnesses and disease associated with the specific microorganism.
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From page 86... ...
This concept has also been suggested as providing the explanation for sporadic cases of infectious disease. Although it is clear that the host defenses (immunity at the cellular and humoral level)
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From page 87... ...
In the future, more human and animal studies will be needed to further address both hazard identification and dose-response assessment, including virulence, strain variation, immunity, autoimmune reactions, and multiple exposures. Exposure Assessment The exposure assessment is aimed at determining the size and nature of the population exposed and the route, concentrations, and distribution of the microorganisms and the duration of the exposure.
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From page 88... ...
FORCES: WORKSHOP PROCEEDINGS LOW HIGH IMEPAALCTT OF RISK OUTCOME TREATABILITN MINIMUM LOW . RISK E XPOSURE HIGH 'a -- .> FIGURE 8 Risk matrix for infectious agents.
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From page 89... ...
This includes some hazard identification and exposure assessment. The system is largely nonquantitative and does not incorporate dose-response or risk characterization.
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From page 90... ...
Several examples can be used to address the risk-assessment process and the relationship to HACCP (Table 12; Figure 10~. BUILDING DATABASES FOR NATURALLY-OCCURRING MICROBIAL HAZARDS AND BIOLOGICAL WEAPONS Although health outcomes and morbidity and mortality statistics are available from numerous databases and surveillance programs, the data lacking are often the long-term assessments and chronic outcomes.
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From page 91... ...
, it is the microbial hazard that influences these attack rates, which correlate well with the dose-response values for the individual microorganisms (Figure 11~. For example, on average, 22% of the populace in the communities exposed developed illness when the drinking water was tainted with Campylobacter, and 53% of the populace became ill during waterborne outbreaks of the Norwalk virus.
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From page 92... ...
FORCES: WORKSHOP PROCEEDINGS 70 60 o a_ ~ 50 ct ~ 40 ct 1 ' <: 30 20 10 o To ~~\,~ c.~9 by'' . ~ .' ~W AGE Microorganism FIGURE 11 Average attack rates by microorganism during waterborne outbreaks.
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From page 93... ...
Health Outcome Databases Associated With Biological Weapons and Terrorist Attacks Figures 13 and 14 demonstrate the outcomes of the Salmonella and Shigella outbreaks associated with the tainted food sources during suspected terrorist acts (Torok et al. 1997; Kolavic et al.
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From page 94... ...
STRATEGIES TO PROTECT THE HEALTH OF DEPLOYED U.S. FORCES: WORKSHOP PROCEEDINGS Infection 74 stools + 231 _ for employees (32%)
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From page 96... ...
Exposure assessment could be defined as monitoring the source of the exposure over time, up to contact, that is, the final food product prior to consumption, the glass of water from the tap, or the aerosol that is inhaled. This is a difficult and impossible task in most cases.
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From page 97... ...
For drinking water, a similar system based on watershed assessment, drinking-water treatment efficacy, and distribution-system integrity is being promoted. In some of these cases, an understanding of infections in the animal or human populations, waste disposal practices, and the transport patterns, survival, and growth of the microorganisms must be Pained and monitoring data must be developed to support the likelihood of exposure through the various pathways.
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From page 98... ...
98 STRATEGIES TO PROTECT THE HEALTH OF DEPLOYED U.S. FORCES: WORKSHOP PROCEEDINGS TABLE 14 Best-Fit Values for Some Fecal-Oral Microorganisms Best-Fit Model Values Exponential Beta-Poissona Microorganism Subject (doses)
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From page 100... ...
In most cases colonization was the criterion used, referred to as infection (clinical diagnosis or antibody response [serology]
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From page 101... ...
mortality dose-response models, these climatic models are extremely useful for comparing risks to various populations and could be used to examine the risks to deployed troops. Data should be gathered on geographic and climatic conditions, along with knowledge on the distribution and density of the vector and the level of infection of the parasite in the vector.
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From page 102... ...
Table 16 is a brief summary of the laboratories. Early in the history of the United States, it was clearly recognized that conflicts, wars, and deployment of troops carried with them special medical needs in regards to infectious disease.
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From page 103... ...
This laboratory also contains an animal facility. DOD Global Emerging Infectious Surveillance and Response System The formal expansion of DOD's mission on emerging infectious diseases in June 1996 by Presidential Decision Directive NSTC-7 now includes global surveillance, training, research, and response.
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From page 104... ...
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From page 106... ...
Opportunities for Research Using a Risk-Assessment Method It is proposed that a risk-assessment framework be used to develop criteria documents or briefs on the various microbial hazards, dose-response models, exposure assessments, and risk characterization, followed by a risk-management strategy. These documents can be used to fill data gaps and then be matched to the capabilities of the various laboratories.
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From page 107... ...
· Geographic, climatic, seasonal, dose-response, and exposure scenarios can be used to develop tools for setting priorities for assessment of predeployment risks. · Risk models can be evaluated for plausibility during outbreak investigations or disease surveillance operations.
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From page 108... ...
1997. Emerging Infectious Diseases.
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From page 109... ...
1988. Assessment of risks associated with enteric viruses in contaminated drinking water.
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From page 110... ...
, Fort Detrick, Maryland. MSMR ~ Medical Surveillance Monthly Report)
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From page 111... ...
, Fort Detrick, Maryland. MSMR (Medical Surveillance Monthly Report)
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From page 112... ...
Addressing emerging infectious disease threats, a strategic plan for the Department of Defense. Presidential decision Directive NSTC-7.
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