Friday, 4 February 2011

Session 5: Feb 8, 2011: Rabies from multiple perspectives: A One Health Exemplar

Session 5: Feb 8, 2011: Rabies from multiple perspectives: A One Health Exemplar
This session will include a 4-part panel with leading researchers, Dr. Charles Rupprecht, Dr. Bob Weedon, Dr. Carl Williams, and Peter Costa. Read on for more information on their presentations. 

Dr. Carl Williams, Rabies: A disease with a comprehensive medical, legal, and public health framework
Rabies is an infectious disease with the highest known case fatality rate, yet human cases of rabies in the US and NC are rare. In fact, a recognized human case of rabies has not occurred in NC since 1955. However, because of the burden of wildlife rabies in NC, and the high numbers of human and animal exposures to the disease, there is a strong public health and legal framework in place to limit the impact of this disease. No other human communicable disease, save perhaps HIV and TB, has such a specific legal framework in place for purposes of control. The success of these legal controls is dependant upon individual citizens and animal owners, physicians and veterinarians, and local and state public health officials working in concert. Rabies control is, and always has been, an ideal example of the concept of “One Medicine.” While rabies control laws are ultimately designed to protect human health, they have the benefit of providing significant benefits to animal health. As a result of compulsory dog, cat, and ferret rabies vaccination laws the number of rabies cases in these species is low. Similarly vaccination of raccoons along the Appalachian ridge against rabies (Oral Rabies Vaccination using Raboral V-RG) has the dual benefit of protecting raccoons in the central US from the raccoon variant of rabies, and protecting people there from many more exposures to rabies.

Learning Objectives:
1.    To understand the rationale for the existence of a legal framework for rabies control.
2.    To know the individual roles and responsibilities of animal owners, bite victims, animal control officers, physicians and veterinarians when dealing with rabies exposures.
3.    To understand basic principles of rabies exposure risk assessment to ensure people exposed receive appropriate care.

Dr. Charles Rupprecht, Rabies: an Epitome of the One-Health Concept
Rabies is one of the oldest infectious diseases, and has the highest case fatality rate of any conventional pathogen. The etiological agents are highly neurotropic, single-stranded, negative-sense RNA viruses in the Family Rhabdoviridae, Genus Lyssavirus. At least 12 different lyssaviruses, all which cause an acute, progressive encephalitis, have been described to date, some with considerable antigenic variation that lack cross reactivity to modern biologics. This zoonosis is distributed on all continents, with the exception of Antarctica. All mammals are considered susceptible, but major reservoirs reside in the Carnivora and Chiroptera. The domestic dog is the major reservoir, and responsible for >90% of human exposures and fatalities. Considering its veterinary impact on the loss of food, fiber, and fur, and public health impact, disability-adjusted life year scores, the burden of rabies lies within the top 10 echelon of global infections. Rabies is the only routine veterinary diagnostic test in which regular concentration upon laboratory results in a suspect animal directly determines human medical intervention. Additionally, animal models serve as the quintessential research subjects for innovative development of modern human prophylaxis and treatment options. Significantly, results of mass immunization programs in domestic and wildlife species demonstrate that rather than concentrate solely upon human rabies prevention, animal rabies can be controlled effectively, and in some cases eliminated locally. Hence, given these key facets alone, of decentralized laboratory-based diagnosis, research model development, and biotechnology/vaccinology, all focused centrally upon the role of non-human animals, with major benefits accruing directly for Homo sapiens, this ancient pariah is an ideal 21st example of the OneHealth concept in action.

Learning Objectives:
1)    To appreciate the value of basic surveillance and laboratory-based diagnosis conducted upon animal reservoirs and their critical role for decision making in human rabies exposures.
2)    To understand the utility of experimental rabies models, as surrogates in pathogenesis studies for relevant disease prevention and treatment in humans and other animals.
3)    To comprehend the historical importance of focusing upon control via vaccine-induced herd immunity, in domestic animals and wildlife, as a barrier to human infection, and a productive means of ultimate disease elimination.

Dr. G. Robert Weedon, The role of animal population control in human rabies prevention
The principal reservoir of rabies in the world is the domestic dog, the cause of >90% of human exposures and fatalities. The World Health Organization has said that control of rabies in domestic dogs can be accomplished by a three-pronged approach: a) epidemiologic surveillance, b) mass vaccination, and c) animal population control.

In most developing nations, only about 5 percent of dogs have owners in the Western sense, compared to 95 percent in the U.S. The rest can be loosely classified as community dogs. These community dogs may be a valued and recognized part of the community, but may not be “owned” in a manner that would provide supervision of movement in the neighborhood and address health needs such as rabies vaccination or population control. Therefore, any attempt to prevent rabies in a community will require both canine vaccination, and, in order to reduce overpopulation of these community dogs, animal birth control.

There is evidence that the combination of sterilization and rabies vaccination of dogs in a community can reduce the incidence of human rabies to zero. Imagine what could be accomplished by incorporating a non-surgical form of sterilization in such programs. The goal of this presentation is to increase awareness of the role of animal population control in rabies prevention campaigns in developing countries.

Learning objectives:
1) To recognize the unique demographics of dog populations, and their role as the principal reservoir of rabies, in developing countries.
2) To appreciate the value of canine sterilization and mass vaccination campaigns in preventing human rabies in communities where the dog is the principal reservoir of rabies.
3) To increase awareness of the potential for non-surgical sterilants and their use in rabies prevention programs in areas where animal overpopulation and human rabies is a problem.

Peter Costa, Health Communication: Bridging Gaps for Rabies Prevention
Rabies is a zoonotic disease that remains a serious public health concern, particularly in Asia and Africa, where the majority of human rabies deaths occur. It is clear that the areas where human rabies remains a major problem are also those areas where canine rabies is endemic. Raising awareness on rabies prevention and control is essential in preventing exposures, increasing the general public’s behaviors towards proper wound care and seeking medical attention. Enhanced awareness can also improve rabies control efforts in animals by increasing reporting of potential rabid animals, improving understanding among the population about the need to vaccinate dogs and behaviors of responsible dog ownership. All of these efforts will lead to improved overall rabies prevention at the local level. The recent establishment of an annual World Rabies Day and the involvement of professional health communicators in rabies outreach represent a major step forward. Fundamental and innovative communication techniques are used to achieve global coordination, galvanize support and empower stakeholders at different levels. Critically, the network also provides rabies advocates in different countries (often working in relative isolation) with an effective support structure and sense of engagement within a concerted international effort.

Learning Objectives:
1.    To list three reasons why rabies remains a neglected zoonotic disease on a global scale
2.    To describe the pivotal role of health communication and community education in effective and sustainable rabies prevention programs
3.    To formulate novel approaches to building partnerships, engaging hard-to-reach populations and overcoming barriers to health communication
Suggested readings for this session are referenced below: