Addressing feral and wild animal threats during deployment: the distinction between animal control and rabies control.
Dunton, Raymond F.
Sargent, Gerald R.
|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|
|Product:||Product Code: 9106280 Wildlife Protection Programs NAICS Code: 92412 Administration of Conservation Programs|
Preventive medicine and veterinary personnel should be prepared to conduct feral and wild animal control on every deployment--it is critical in the Iraq theater of operations. Animal bites take both service members and military working dogs out of the fight and place a preventable burden on medical care and logistics systems. Feral, as used in this article, refers to ownerless dogs and cats that have reverted to the wild state and lack characteristics associated with domestication.
Iraqi cultural and religious beliefs (dogs and cats are considered dirty; they are seldom kept as pets), the absence of a government-backed animal/zoonotic disease control program, and the new food and water sources on US bases in Iraq led to the establishment of unacceptable animal populations soon after the bases were occupied. This, in turn, led to the development of the Theater Animal Control Program early in Operation Iraqi Freedom.
Military animal control during deployments has neither the same goals nor the same options as a government-sponsored, long-term zoonotic disease control program. The focus of a military preventive medicine contingency animal control program is to reduce animal contact and human injury. A national rabies control program is designed to reduce zoonotic disease.
A successful rabies control program requires a long-term government commitment, either at the regional or national level. In its guidelines for canine rabies control, the World Health Organization (WHO) recommends mandatory vaccination of owned animals, movement restriction, and reducing the number of ownerless animals by euthanasia. (1) The WHO also recommends that nontraditional canine rabies control programs such as the oral rabies vaccine not be started without first collecting at least 5 years of data on dog population parameters and infection rates. (2) As an example of the level of commitment required, it took almost 60 years of national effort to rid the United States of dog-to-dog rabies transmission. (3) While a properly run program of this type will reduce the incidence of rabies over time, it cannot be expected to have any impact on US contingency bases in the absence of a national program.
Canine Rabies Control
Rabies is an acute viral encephalomyelitis that principally affects carnivores and insectivorous bats, although it can affect any mammal. It is almost invariably fatal once clinical signs appear; there are only 6 documented cases of humans recovering from rabies following appearance of clinical signs. (4) Reservoirs of rabies vary throughout the world. Canine rabies predominates in Africa, Asia, Latin America, and the middle east. (5) According to the World Health Organization, there are about 55,000 deaths from rabies annually, mostly in Asia and Africa. (6)
The WHO lists 3 basic elements of a successful rabies control program: epidemiological surveillance, mass vaccination, and dog population control. (1) In areas that have large populations of ownerless dogs such as Iraq, the WHO recognizes that mass parenteral vaccination may not be possible (1,2) Control or elimination of canine rabies is possible as demonstrated by successes in the US, Japan, and other countries. (1) These control efforts required long-term commitment, wide-area coverage, local population buy-in, significant managerial investment, and legislation.
The Centers for Disease Control and Prevention's (CDC) program in the US is viewed as a model of success by the WHO.1 The CDC's 2008 program (7) advocates mandatory vaccination of owned animals and removal of unwanted animals/animal control as cornerstones. In support of the national rabies control program in the US, city and county programs collectively euthanize almost 10 million animals every year. (8) This underscores the fact that there are far more stray animals in the US than can be adopted. The problem is magnified in a country like Iraq where there is no organized rabies control program and people do not keep pets. Most medium-sized cities and counties in the US kill more animals annually than the US does theater-wide in Iraq. Table 1 provides a comparison between animal euthanasia in Iraq and representative US districts.
The CDC plan also emphasizes supporting activities including public education, ongoing surveillance, and identification of vaccinated animals. As a result of many years of national commitment, the US has gone from almost 7,000 rabies-positive dogs per year in the late 1940s to declaring the country free of dog-to-dog rabies transmission less than 60 years later. (3) Sporadic canine infections continue to be reported in the US (71 in 2006). (3) these infections are attributed to spillover from virus types that circulate in wild animal populations. (3) Mass vaccination campaigns combined with euthanization of ownerless dogs has also been used in Malaysia, another country that has succeeded in eliminating canine rabies. (1)
In addition to mass parenteral vaccination of owned animals and elimination of strays, the WHO has suggested 2 supplementary approaches for consideration in some situations. (1,2)
Oral Rabies Vaccine (ORV). Successful wild animal rabies control programs that incorporate the ORV have been run in several countries. (1) The ORV is a potentially useful tool for canine rabies control in countries where a large percentage of the dogs are ownerless or where the target reservoir is a wild animal species. A successful ORV canine rabies control program would still have to be region- or country-wide and require long-term national commitment. The WHO recommends considering the following criteria before deciding to use ORV for control of rabies in dogs (2):
* Dog rabies is endemic.
* A monitored dog rabies vaccination program by parenteral vaccination is in place for the last 5 years and is permanently evaluated.
* Commitment of the authorities is demonstrated by allocation of sufficient annual budget for the operation of the rabies surveillance and control program.
* There is a network of biomedical services and diagnostic laboratory capacity established in the country and historical data on human and animal rabies cases for at least the 5 previous years are available.
* Dog demography information (population size estimates, density, distribution, age structure, turnover, etc) is available.
A properly managed ORV campaign could eventually reduce the prevalence of rabies in the target population, but it is not appropriate for military contingency purposes. It does not address the numbers of animals on bases, it will not change how we treat bite victims, and it will foster a false sense of security that could lead to increased violation of General Order Number 1, which prohibits the adoption of pets and mascots. The suggestion that we should use ORV to vaccinate animals inside our bases, and that this would allow us to stop euthanizing animals, ignores the primary goal of Army contingency animal control: reducing the number of human-animal encounters. In the absence of an ongoing national program, spreading ORV bait throughout the installations of deployed US forces protects neither military personnel nor the local population.
Trap-Neuter-Return (TNR) or Animal Birth Control. In 1990 the WHO published guidelines for rabies control programs built around the sterilization, vaccination, and release of dogs. (9) It was thought that this would reduce the size of the dog population, the number of animals susceptible to rabies infection, and ultimately the number of human infections. While it may have potential in some situations, a military deployment is not one of them. TNR will not reduce human-animal encounters, does not protect military personnel, is impractical in terms of work load for deployed veterinarians, and therefore should not be considered in a contingency situation.
There is an ongoing debate in the United States on the utility of TNR programs designed to control the size of animal populations, (10-12) (not rabies control programs), with more evidence against than for TNR. Discussions regarding the best way to address feral animal population control in the US typically have an emotional component, with people averse to euthanasia advocating TNR. (13,14) In many instances, this has been the primary impediment to solving a feral animal problem. (15,16)
Focusing strictly on rabies control, there is very little hard evidence that TNR programs are effective. The WHO itself states that, almost 20 years after they issued guidance on conducting this type of program, "... the results are promising, but data are limited and independent evaluation of projects has not yet been undertaken". (1)
Vaccination of owned animals and elimination of strays are the mainstays of WHO rabies control recommendations. An ORV program may be of value for controlling rabies in wild populations or in large populations of ownerless dogs, but ORV and TNR are not good options for the US military on deployment. None of the rabies control approaches address the basic goal of military contingency animal control.
Animal Control in a Contingency Environment
The primary goal of military animal control in a contingency environment is to reduce the feral animal population inside US bases. This has at least 5 distinct benefits:
* Reduces human-animal contact and thus the likelihood of human injury by an animal.
* Reduces the disease reservoir population.
* Reduces damage to personal and government property.
* Reduces interference between military or contract working dogs and feral animals.
* Allows us to produce data on zoonotic disease prevalence in the animal populations.
The Army's approach for contingency deployments, euthanization of ownerless animals inside the base perimeter, addresses all of the threats posed to US and coalition forces by animals. Rabies control methods do not. Historically, the chain of command has authorized and advocated very basic means of animal control, such as kinetic force, early in a deployment and on more remote bases, acknowledging the importance of limiting human-animal contact. As the theater matures, animal trapping and chemical euthanasia become the norm, at least on the larger bases.
It is essential that preventive medicine and veterinary services personnel, installation commanders, and contractors in theater work closely together in the initial development of a comprehensive animal control program. Army Preventive Medicine Sciences officers, and enlisted Preventive Medicine Specialists (MOS * 68S), have primary responsibility for contingency animal control in their pest management role. They build a team to assess the problem, develop a plan to address the problem, and make recommendations to commanders regarding animal control.
Veterinary Officers (Area of Concentration 64A/64B) and enlisted Animal Care Specialists (MOS 68T), consult on the initial development of the animal control plan, provide euthanasia support, collect disease surveillance data using the trapped animals, and provide quality control oversight to the program. This support will vary depending on mission priorities and number of veterinary personnel available. Veterinary services are responsible for euthanasia whenever personnel are available. They should also provide oversight and guidance when others must euthanize trapped animals to ensure that humane methods are being used in accordance with current American Veterinary Medical Association Guidelines. (17)
While preventive medicine has overall responsibility for animal control, installation commanders assume responsibility for implementing trapping programs on their bases. Base programs are developed based on theater guidance and support the theater plan. Both preventive medicine and veterinary service personnel should monitor these programs to ensure the use of proper trapping methods and humane treatment of animals.
Deployment animal control has been conducted during most of Operation Iraqi Freedom (OIF) in much the same way as in other US deployments. Although it is not a viable option as a long-term disease control program, animal trapping combined with humane euthanasia of trapped animals is effective at reducing the threat and frequency of Soldier injury by animals on US bases. The program used by the US Army and other military services deployed in support of OIF is designed to reduce the number of animals "inside the wire."
Preventive medicine's focus with regard to animal control has been and must continue to be very limited--protect our military personnel, DoD civilians, contractors, and coalition partners from animal injuries. Euthanizing trapped animals accomplishes this, and in addition reduces the available disease reservoir population. Military and contract working dogs have a proven record of protecting US forces. However, in situations where unrestrained feral dogs exist, these working dogs may be harassed, attacked, and distracted from their duties. Euthanizing animals trapped on coalition bases also provides the opportunity to generate data on zoonotic disease prevalence in the theater of operations which currently does not exist. (1,18,19)
While some have suggested that we should not euthanize animals and even that some animals should be released, it is critical that all animals known to be zoonotic disease reservoirs trapped in a contingency environment be euthanized. In Iraq, contract vector control personnel have not trapped an endangered or threatened animal during more than 5 years of animal control operations on US bases. Moreover, the National Center for Medical Intelligence (NCMI, formerly the Armed Forces Medical Intelligence Center) lists fox and jackal as the primary reservoirs of rabies in Iraq. (19) The International Union for the Conservation of Nature (IUCN), referenced in the 2007 Iraq Animal Control Plan, lists no endangered or threatened mammals that are likely to be caught incidentally during the animal control trapping program. The IUCN is currently tracking 5 endangered and 9 vulnerable mammals in Iraq, (20) listed in Table 3.
Iraqi cultural and religious beliefs explain in part why there are so many feral dogs and cats in Iraq. Iraqis do not keep pets such as dogs and cats, because they are considered unclean and are not allowed in the house. The other major factor that has resulted in a large feral animal population is that there was no regional or national program to address this health threat before September 2008.
Animal trapping and euthanizing trapped animals works on deployment in general and on US bases in Iraq in particular because we concurrently do 2 other things: movement restriction and habitat modification. (1) The walls and fences around our bases, while not completely impassable, serve to limit animal movement onto the bases. Refuse on bases is managed in much the same way that it is in the US, which limits food sources for animals. While animal-proof compounds are not a realistic expectation, both waste management and exclusion are continually improved throughout the theater. Holes under walls and in fences were identified and repaired, more incinerators were put into operation, and burn pit management was improved.
The US feral and wild animal control program in Iraq was effective in reducing the number of animals to which coalition forces are exposed. Organized animal control has been conducted continuously on major US bases in Iraq since the beginning of Operation Iraqi Freedom in 2003. Contract vector control personnel trapped approximately 14,000 feral and wild animals, such as those shown on page 39, in 2005; 6,500 in 2006; and 7,092 animals in 2007 (Table 1). This is a good indication that the program is working--reducing the number of feral animals on our bases.
For the deployed US military, some type of animal control will often be necessary, and animal trapping and euthanasia will remain the standard. In countries with large feral animal populations such as Iraq, animal control is a critical component of force health protection. In the absence of a functioning national disease control program, it is the only tool we have that addresses injury by animals and effectively reduces the zoonotic disease reservoir population.
If US forces are tasked to assist the Iraq government in the establishment of a sustainable national animal or zoonotic disease control program, it will be critical to understand both the Iraqi culture and the programs that have worked in other countries. Since Iraqis do not keep pets and consider dogs and cats to be unclean, a program that includes euthanasia would probably receive more support than one that advocates sterilization and release of animals. An ORV program is ill-advised for the same reason.
Until about 25 years ago, the Iraq government paid a bounty for dogs and cats, dead or alive. Apparently, this program worked very well and reduced the feral animal populations significantly in Iraq. Resurrecting the program could be the solution to the country's feral animal problem. In November 2008, the government of Iraq initiated kinetic dog control in Baghdad to prevent rabies transmission and stop feral dog packs from killing people. Expanding this initiative to other population concentrations will benefit all Iraqis.
The US must continue to make improvements to installations that will limit the number of animals gaining entrance to our bases. This includes maintenance of barriers such as fences and walls, and also taking steps to exclude animals from dump sites as much as possible. We must continue to improve burn pit management where necessary, and continue efforts to increase the number of incinerators in use in the theater. Finally, our expectations for animal exclusion efforts must be tempered with a clear understanding of the costs versus benefits--neither bases nor burn pits can be made completely animal-proof.
Whenever and wherever our Army deploys, we must be prepared to conduct animal control operations as necessary. In Iraq, the US military must stay the course with its animal trapping and euthanasia program until the Iraqi government is able to establish a program that addresses the feral animal problem throughout the country, and that program begins to show positive results. To do anything else increases health risks to Soldiers.
(1.) Who Technical Report Series No. 931. WHO Expert Consultation on Rabies, First Report. Geneva: WHO Press; 2005.
(2.) Oral Vaccination of Dogs Against Rabies. Geneva: World Health Organization: 2007. Available at: http://www.who.int/rabies/resources/guidelines% 20for%20oral%20vaccination%20of%20dogs% 20against%20rabies_with%20cover.pdf. Accessed June 24, 2009.
(3.) Blanton JD, Hanlon CA, Rupprecht CE. Rabies surveillance in the United States during 2006. J Am Vet Med Assoc. 2007;231:540-556.
(4.) Willoughby RE, Rotar MM, Dhonau HL, et al. Recovery of a Patient from Clinical Rabies--Wisconsin, 2004. MMWR Morb Mortal Wkly Rep. 2004;53:1171-1173.
(5.) Aiello SE, ed. The Merck Veterinary Manual. 8th ed. Whitehouse Station, NJ: Merck & Co, Inc; 1998:966967.
(6.) World Health Organization. Human and animal rabies. Available at: http://www.who.int/rabies/en/. Accessed May 15, 2009.
(7.) Compendium of Animal Rabies Prevention and Control, 2008. MMWR Morb Mortal Wkly Rep. 2008;57(No.RR-2).
(8.) Animal Shelter Euthanasia. American Humane Association web site. Available at: http://www.americanhumane.org/about-us/newsroom/factsheets/ animal-shelter-euthanasia.html. Accessed June 25, 2009.
(9.) Bogel K. Guidelines for Dog Population Management. Geneva: World Health Organization & World Society for the Protection of Animals; 1990. Available at: http://whqlibdoc.who.int/hq/1990/ WHO_ZOON_90.166.pdf. Accessed June 25, 2009.
(10.) Andersen MC, Martin BJ, Roemer GW. Use of matrix population models to estimate the efficacy of euthanasia versus trap-neuter-return for management of free-roaming cats. J Am Vet Med Assoc. 2004;225 (12):1871-1876.
(11.) Levy JK, Gale DW, Gale LA. Evaluation of the effect of a long-term trap-neuter-return and adoption program on a free-roaming cat population. J Am Vet Med Assoc. 2003;222(1):42-46.
(12.) Castillo D, Clarke AL. Trap/neuter/release methods ineffective in controlling domestic cat "colonies" on public lands. Nat Area J. 2003;23(3):247-253.
(13.) Sleeman JM. Additional input on feral cat debate. J Am Vet Med Assoc. 2003;223(12):1729-1730.
(14.) Tim RM. Trends in wildlife management in North America. Outlooks PestManag. 2005;16(5):215-219.
(15.) Hawkins CC. Feral cats, colonies, and wildlife. Outlooks Pest Manag. 2005;16(4):177-178.
(16.) Wolff EF. Final letters for now on feral cats. J Am Vet Med Assoc. 2002;221(11):1548.
(17.) AVMA Guidelines on Euthanasia. Schaumburg, Illinois: American Veterinary Medical Association; 2007. Available at: http://www.avma.org/issues/ animal_welfare/euthanasia.pdf. Accessed June 25, 2009.
(18.) Communicable Disease Profile Iraq. Geneva: World Health Organization; 2003. Available at: http:// www.who.int/infectious-disease-news/IDdocs/ whocds200317/1profile.pdf. Accessed June 25, 2009.
(19.) Baseline Infectious Disease Risk Assessment, Animal Contact Diseases page. National Center for Medical Intelligence web site. Available at: https:// www.intelink.gov/ncmi/product/idra.php? id=64706#Rabies. Accessed July 1, 2009.
(20.) International Union for Conservation of Nature and Natural Resources. IUCN Red List of Threatened Species. Available at: http://www.iucnredlist.org/ static/introduction.
LTC Dunton is Director, Proponency Office for Preventive Medicine--San Antonio, and a Medical Entomology Staff Officer at the US Army Medical Command, Fort Sam Houston, Texas.
MAJ Sargent is Chief, Animal Medicine Division, US Army Veterinary Command, Fort Sam Houston, Texas.
LTC Raymond F. Dunton, MS, USA
MAJ Gerald R. Sargent, VC, USA
* Military occupational specialty
Table 1. Numbers of dogs and cats euthanized by year in the Iraq theater of operations and in 3 representative US locations. Iraq * San Antonio, Albuquerque, TX ([dagger]) NM ([dagger]) 2005 14,000 37,927 16,306 2006 6,500 ([double dagger]) 33,785 14,839 2007 7,092 32,210 12,003 Ft. Hood, TX ([dagger]) 2005 500 2006 981 2007 900 * Numbers for Iraq are from contract vector control records and do not include animals euthanized on bases that did not have permanent contract presence. ([dagger]) Three United States representative districts are provided for comparison: a large city (San Antonio), a medium-sized city (Albuquerque), and a primarily rural Army installation (Fort Hood). Data supplied by local humane societies. ([double dagger]) Iraq 2006 data was incomplete. Table 2. Comparison of the ability of deployment animal control (trapping and euthanasia) and 2 rabies control programs to reduce human-animal encounters. The comparison uses selected parameters of importance in a general deployment setting and specifically in the Iraq theater of operations. * Control Measures Parameters of Importance Animal Trapping & Euthanasia ([dagger]) Protection from animal [check] bites Immediate reduction of [check] ([section]) rabies risk to Soldiers Protection from other [check] diseases (leishmaniasis, cryptococcosis, Q fever) Keeps animal [check] populations at acceptable levels Reduces rabies risk from [check] jackal & fox ([double dagger]) Provides rabies [check] # prevalence data for risk assessments Reduces threatened No animal population ([dagger][dagger]) Affect Makes people [check] uncomfortable or increases stress ([dagger][dagger]) Control Measures Parameters of Importance Oral Rabies Vaccine Protection from animal No bites Affect Immediate reduction of No rabies risk to Soldiers Affect Protection from other No diseases (leishmaniasis, Affect cryptococcosis, Q fever) Keeps animal No populations at Affect acceptable levels Reduces rabies risk from [check] ** jackal & fox ([double dagger]) Provides rabies No prevalence data for risk Affect assessments Reduces threatened No animal population ([dagger][dagger]) Affect Makes people No uncomfortable or Affect increases stress ([dagger][dagger]) Control Measures Parameters of Importance Sterilize, Vaccinate, & Release Protection from animal No bites Affect Immediate reduction of No rabies risk to Soldiers Affect Protection from other No diseases (leishmaniasis, Affect cryptococcosis, Q fever) Keeps animal No populations at Affect acceptable levels Reduces rabies risk from No jackal & fox ([double dagger]) Affect Provides rabies No prevalence data for risk Affect assessments Reduces threatened No animal population ([dagger][dagger]) Affect Makes people No uncomfortable or Affect increases stress ([dagger][dagger]) * The assessment of the rabies control programs assumes no established national program, as is the case in Iraq. ([dagger]) For the US DoD in a contingency environment, trapping and euthanizing animals on US bases provides the most protection for deployed personnel. ([double dagger]) The primary rabies reservoirs in Iraq according to the WHO and NCMI. ([section]) Some infected animals are removed from the population, but this is not measurable because tests are not available that identify infected animals prior to the time that they become infective. Reducing the number of animals on US installations makes human-animal encounters less likely and thus contributes to reducing rabies risk and damage of personal and government property. ([paragraph]) If captured animals are euthanized. # If captured animals are tested. ** Rabies risk reduced from those animals that consume the bait. ([dagger][dagger]) No Affect is the desirable result for this parameter. Table 3. Iraq mammals currently listed as Endangered (blue rows) and Vulnerable by the World Conservation Union (http://www.iucnredlist.org). Common Name scientific Name Blue Whale Balaenoptera musculus Persian Fallow Deer Dama mesopotamica Asiatic Wild Ass Equus hemionus Bunn's Short-tailed Bandicoot Rat Nesokia bunnii Arabian Oryx Oryx leucoryx Cheetah Acinonyx jubatus Long-fingered Bat Myotis capaccinii Mehely's Horseshoe Bat Rhinolophus mehelyi Indian Smooth-Coated Otter Lutrogale perspicillata Brown Bear Ursus arctos African Lion Panthera leo Goitered gazelle Gazella subgutturosa European Marbled Polecat Vormela peregusna Finless Porpoise Neophocaena phocaenoides
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