Author: Czerw, Russell J.
Pub Date: 07/01/2009
Publication: Name: U.S. Army Medical Department Journal Publisher: U.S. Army Medical Department Center & School Audience: Professional Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2009 U.S. Army Medical Department Center & School ISSN: 1524-0436
Issue: Date: July-Sept, 2009
Accession Number: 242963581
Full Text: Among the more well-known of the ancient Chinese maxims of military principles attributed to Sun Tzu is "Know your enemy as you know yourself," a common sense requirement for anyone planning strategy and tactics for an impending conflict. Of course, one immediately thinks of intelligence operatives gathering information about the character of the enemy's forces, locations, capabilities, and support structure, among other things, and analysts examining that data to identify ways to counter and eliminate the threat. The same approach applies not only to opposing military forces, but also to any adversary with the potential to inflict harm on your force and reduce its combat capability. As we have learned from hard experience over the last 110 years, some of the most pernicious threats to our Soldiers are posed by the smallest of adversaries--mosquitoes, ticks, sand flies, fleas, mites, and other arthropods--which cause problems directly through bites and irritation, and, more importantly, vector some of the most virulent disease pathogens that afflict humans and other mammals.

Ever since MAJ Walter Reed confirmed and extended Dr Carlos Finlay's previously ridiculed theories about the role of an arthropod, the mosquito, as intermediary host in the spread of yellow fever, the need to know this constant, pervasive enemy has been recognized by the military. Further, as understanding of the extent and significance of the threat has grown, the military's organization and application of resources has become increasingly sophisticated, with military entomologists on the point. The US Army first commissioned entomologists into the Sanitary Corps during World War I, and significantly increased those numbers during World War II. Today, there are some 64 active duty and 35 reservist Army entomologists serving in a variety of roles in operational commands, on staffs, in research laboratories, and in training organizations, often jointly with entomologists from our sister services. The senior medical and veterinary entomologist at the Army Medical Department (AMEDD) Center and School, COL Mustapha Debboun, has organized this special focus issue of the AMEDD Journal to feature the work of those military entomology professionals, including contributions by Air Force, Navy, and civilian authors. The result is an outstanding issue that is not only a wealth of important, timely medical information, but also provides insight as to the broad scope of roles and responsibilities of medical entomologists in today's military.

Although the role of arthropods as vectors of disease pathogens is, understandably, the best known of the threats they pose, there are other hazards. In the first article, CPT Silas Davidson and his coauthors present an excellent description of the problems caused by beetles that do not sting or bite, but secrete vesicating chemicals which cause blistering in human skin. These blisters are often misdiagnosed, and have sometimes even been attributed to suspected chemical warfare agents. In certain parts of the world, the beetles periodically swarm in numbers large enough to pose a considerable health threat, and have in fact adversely affected military operations. The biology of the production of the irritant, and the physiology of its harmful effects are clearly explained as the authors use an outbreak of dermatitis among US Soldiers in Iraq in 2007 as a case study to illustrate the reality of the threat to readiness. It was discovered that the possibility of vesicating beetles had not been considered as Soldiers and Airmen at Joint Base Balad were being treated for blisters, assumed to be burns from maintenance activities. Sampling at the locations where the affected personnel worked revealed the presence of such beetles, and further collections determined the types of beetles, potential sources, the attraction factors (lights), and the times of activity. Based on the data collected, preventive measures were instituted to reduce human contact with the beetles, and the incidence of dermatitis was significantly reduced. This very informative article is a textbook example of how the teamwork of the healthcare provider and the entomologist effectively identified and resolved a potentially serious public health concern.

By the end of World War II, US military planners understood that learning, or relearning, the particulars of regional disease threats each time US forces deployed was counterproductive, and often proved deadly to military personnel. Overseas medical research laboratories were established in Thailand, Indonesia, Peru, Egypt, and Kenya to minimize such knowledge gaps by developing and using surveillance tools to discover and understand the spread of disease and the vectors involved. MAJ Brian Evans has assembled a team of authors representing all five of those laboratories to present an examination of the most serious disease threats targeted by their research, and describe the ongoing work to address the gaps in our knowledge and capabilities to counter them. In a well-developed, very informative article, they carefully lay out the core questions that pertain to the particular vector of concern, and how the answers drive the approach to developing preventive measures to mitigate the respective threat. This article is detailed and complete in its approach that defines the task necessary, identifies the deficiencies encountered in accomplishing the task, and describes the solutions under development to address those deficiencies. However, even though the information presented is extensive, it is only a snapshot of the fascinating and extremely important work under way in those laboratories by our military and civilian entomology professionals.

One advantage of dealing with a vector-borne disease is that the potential occurrence of the disease in a given area is predictable, as long as the absence or presence of the vector can be determined. Unfortunately, that is often the most difficult aspect of the medical threat assessment, in that surveillance of vectors in the area may be impossible prior to deployment, and even after arrival in a combat environment. MAJ Michelle Colacicco-Mayhugh has contributed a very interesting article which looks at one way technology is providing assistance to planners for this problem. The adaptation of remotely sensed data into a number of modeling techniques is providing basic information about distribution, ecology, and the potential range of species without the collection of actual sampling data. By combining what is known about the vector species' biological and environmental requirements with the environmental and geographic data obtained from remote sensors, ecological niche modeling allows planners to determine if conditions in a geographic area are favorable for a given vector, and to assign probabilities to their occurrence. Obviously, this information is of great value to preventive medicine planners in that it allows them to sharpen their focus in their assessments, reducing the unknowns by a considerable amount. MAJ Colacicco-Mayhugh's article is a concise, clearly presented description of niche modeling as a potentially invaluable tool for those planning not only combat deployments, but also humanitarian assistance missions in remote parts of the world.

Although military entomologists are usually focused on management of the smallest of pests, they often share responsibilities with military veterinarians in dealing with feral and wild animals in deployment areas. LTC Raymond Dunton and MAJ Gerald Sargent have contributed an important article that addresses their experiences in this area while deployed to Iraq. Their article provides detailed insight into an often controversial area of public health, the significant differences in purpose and capabilities between contingency animal control efforts and rabies control programs. Ideally, a military deployment is temporary and localized, contending with environmental and public health concerns which directly affect the readiness of the force. Invariably, there is contact between deployed personnel and feral dogs and cats, as well as wild animals drawn to the deployment area by the increased availability of food, either as predators or foragers. Resulting animal bites take military personnel away from their duties until the status of potential rabies infection has been determined, and resources are dedicated to locating, capturing, and examining the animal involved. In their explanation of why the military must use capture and euthanasia as animal control measures, LTC Dunton and MAJ Sargent clearly and completely explain the various rabies control measures that are used as part of long-term, national programs designed to first reduce zoonotic disease, but often with reduction in the numbers of animals as only a secondary effect. They explain why such measures are neither practical nor effective in protecting personnel in a localized, temporary situation, and how the military works very hard to minimize animal movement into the bases, thus reducing the requirement for euthanasia as much as possible. The information in this article should be used in predeployment training to expose personnel to the "whys" of the Army's animal control policy, which, to the uninformed, may seem harsh. Such concerns are distracting and counterproductive to accomplishing the military mission of the deployment.

Identification of arthropod species is one of the most important skills that a military medical entomologist must have. Recognition of disease vectors during surveillance is the vital first step in planning and implementing countermeasures to the disease threat they represent. As with every other extensive field of science, entomology has many areas of expertise among its specialists, but those entering the military must be proficient in species recognition and identification--our Soldiers' health depends on their ability. Such training has been expensive and time consuming, involving contracting classes and experts. In their informative article, Navy CDR (Ret) George Schultz and Dr Richard Robbins introduce a project by the Armed Forces Pest Management Board to provide training in species identification using interactive programs available on computer CDs and DVDs. They describe in detail the 3 initial remote teaching programs focusing on ticks and mosquitoes, and include illustrations of their functionality and interactive capabilities. The advantages in accommodation of student schedules, flexibility of use, and cost effectiveness are clearly explained. This is an exciting first step in training in a specific skill set that is undoubtedly adaptable into many other areas that require specialized medical training of smaller student populations.

For most people, perhaps the most common of arthropod pests are the various species of house flies. These ubiquitous insects are not only annoying, but have been recognized for many years as threats to human health as transporters of a considerable array of human pathogens. The presence of house flies is especially problematic in deployed environments, where public health infrastructure to support sanitation and hygiene may not exist, or, in many cases, has never existed. Their large numbers pose significant challenges for our military preventive medicine professionals in reducing both their existing numbers and their reproduction rates. Unfortunately, we have learned that house flies are extremely adaptable, rapidly developing resistance in their breeding cycles to our attempts to control them with insecticides. Two University of California at Riverside scientists, MAJ Alec Gerry (USAR) and Dr Diane Zhang, investigated the rapidly spreading resistance to a common fly bait that house flies in southern California have demonstrated since 2003. They describe their well researched, carefully designed study in a fascinating article that reveals the complexity of attempting to identify whether the generational change is increased physiological resistance to the bait's toxic component, a change in behavior by which the flies increasingly avoid the bait, or a combination of both. Their study is an illustration of the scientific rigor that must be applied when examining a phenomenon that has multiple, perhaps interacting causes which may also be changing over time. Further, this study is a classic example of an area of public health research that clearly has significant value for both military and civilian applications.

The problems of obtaining data and understanding the situation with regard to vector-borne diseases is not limited to remote areas with no advanced medical surveillance and laboratory resources. The US military has had a continuous, significant presence in the Republic of Korea (ROK) for over 50 years, and a tremendous amount of work has been done in improving public health and dealing with vector-borne diseases. However, as LTC William Sames and his coauthors point out in their detailed, very informative article, much is still unknown about the presence and distribution of a number of tick- and rodent-borne pathogens that cause serious illnesses in humans. This is due to a number of factors over the years, and, as pointed out in the article, the ROK government and US military are both placing increased emphasis and resources into surveillance, tracking, and analysis of disease data, and research into the vectors and pathogens throughout the country. Because the presence of these diseases may not be well known, the potential for misdiagnosis is significant. This well-researched, carefully developed article contains important information for healthcare providers who provide services to military personnel stationed in the ROK, or to those who rotate there on training deployments.

The first line of the individual Soldier's defense against arthropod-borne pathogens is the proper use of personal protective measures, particularly the application of an effective repellent. The most widely produced and used repellent, 7V,7V-diethyl-3-methylbenzamide (deet), was developed in 1954, but over the last decade has come under increasing critical scrutiny for associated adverse effects and other troubling chemical properties. LTC Van Sherwood and his team have contributed an excellent article reporting a formal study they performed in Kenya evaluating deet in comparison with 4 other commercially produced repellent formulations against mosquitoes. This was a detailed, scientifically rigorous field study involving volunteers and careful data collection and analysis. LTC Sherwood et al point out that although the work performed and data analysis of this study were extensive and did produce solid results, the study should be contributory to additional studies exploring other aspects of repellent effectiveness, under other conditions. This article is another excellent example of the high caliber of work being performed every day by the US military's dedicated scientific professionals in our overseas laboratories.

One method for rapid application of pesticides over large areas is aerial spraying. Although on the surface it may appear to be a straightforward process involving special equipment and skillful flying, in reality it is a much more complex undertaking. USAFR Maj Mark Breidenbaugh and his coauthors have contributed a fascinating article which reports on the test and evaluation trials that the USAF Aerial Spray Unit performed to determine the character and dispersal of the spray patterns generated by a new fuselage-mounted spray boom configuration installed on their C-130H airplanes. Generation of predictable droplet size and prediction of drift are key parameters in planning effective aerial pesticide spray applications, especially for mosquito control. Therefore, the new configuration had to be carefully tested to evaluate the effect of the airplane's turbulence on droplet size and drift, under various atmospheric conditions. This article is an illuminating presentation of the myriad of details, calculations, considerations, and allowances which must be included in planning spray missions, not only considering the weather and coverage areas, but the species of the target pest as well. Different species may require different droplet sizes and dispersals to be effective, and may also have different optimal times of application, which could then affect the configuration of the delivery system. This article gives insight into the high level of expertise and professionalism that is required for this very specialized capability, which is extremely important to both the military and civilian emergency management agencies.

The extent of the serious impact of diseases on combat effectiveness, especially in large-scale, extended hostilities, was fully understood after World War II and the Korean War, and military leadership realized that addressing that threat was a full-time effort, in periods of both peace and war. In addition to establishing the overseas laboratories, a centralized activity was envisioned to coordinate efforts and resources, and ensure the timely availability and exchange of current pest management information across the services. The predecessor of the Armed Forces Pest Management Board (AFPMB) was created in 1956 and chartered to be the US military's clearinghouse in support of US forces worldwide in the prevention of arthropod-borne diseases, as well as losses from other forms of pest attacks. USAF Col William Rogers, Dr Richard Robbins, and Navy CAPT Stanton Cope of the AFPMB have contributed an excellent article describing the history, responsibilities, organization, and functioning of the AFPMB. Among other important resources provided by the AFPMB, the article details the Literature Retrieval System which accesses the AFPMB's extensive reference library, one of the world's most highly respected sources of information in vector-borne diseases and medically related zoological topics, especially entomology. In addition, the authors highlight the important role AFPMB plays in careful management of pest control products, ensuring that military pest control efforts are environmentally sound, and, above all, safe for all concerned.

Soldiers in many tactical environments must use camouflage face paints to improve their concealment, especially in jungles or other areas of foliage and trees. Operations in such areas also make Soldiers vulnerable to arthropods, and to the disease pathogens they may carry. As mentioned earlier, the first defense in such situations is proper use of personal protective measures, especially repellents. Application of the separate face paint and repellent is a 2 step process, repellent first, then paint. The Army has developed a formulation of face paint combined with 30% deet repellent to eliminate that second step, and reduce the number of items involved. The development process had to ensure that the efficacy of neither the paint nor the deet was compromised in the blend, and the product had to be field tested before it could be accepted and put into production and distribution. In their article, MAJ Kendra Lawrence and her coauthors present a detailed, well-developed report on the field trials of the combined product. The tests were conducted in rural Belize, using local volunteers, and were designed to be scientifically rigorous and thorough, examining every aspect of product effectiveness and safety. The data was analyzed producing extensive statistical profiles of effectiveness against a number of mosquito species. The article by MAJ Lawrence et al is yet another example of the professional skills and technical expertise of AMEDD professionals that directly benefit our Warriors in every tactical environment and situation.

As the science of identification and analysis of vectors and their pathogens has become increasingly more sophisticated, our ability to plan and counter the threats they impose have markedly improved. However, no matter the capabilities of laboratory science, the first requirement of the process remains basic--specimens of the potential vectors must be collected in the field. In their article, CPT Lee McPhatter, Cara Olsen, and COL Mustapha Debboun describe their study into ways to refine the methodology of collecting specific mosquito species, especially gravid female mosquitoes which provide the best estimate of an infected population. We are all familiar with the commercial types of mosquito control traps, especially the light and CO2 attractant versions, but research has show that any trap must use a lure to be truly effective. In order to attract and ultimately trap gravid female mosquitoes, research such as that described in this article must determine the type of aquatic site that a mosquito species prefers for depositing eggs. CPT McPhatter et al infused a variety of organic substances in water to examine their respective effectiveness in traps placed in a variety of locations across Fort Sam Houston. Their detailed, clearly written article presents the methodology, results and analysis of a well-researched, carefully planned and executed study project. Their work is another important contribution to the ever-growing body of vital scientific knowledge with which we better know and combat these dangerous and evolving scourges to human health.
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