GLOBAL HEALTH | Addressing the world’s health challenges
20 July 2007
Emerging Diseases Drive Human, Animal Health Alliance
"One Health" is a growing international effort to fight disease at source
Washington -- The spread of highly pathogenic avian influenza across 60 countries since 2003 has done more than kill millions of birds and 192 of 318 infected people. It has spurred many veterinary and medical professionals to join forces against emerging diseases, most of which originate in animals.
In the United States, for example, in June, the 244,000-member American Medical Association adopted a "one health" policy, calling for closer ties and more educational and research collaborations between the human and veterinary medicine professions.
In July, during the 144th annual American Veterinary Medical Association (AVMA) convention in Washington, officials from the U.S. State Department, the Centers for Disease Control and Prevention (CDC), the U.S. Department of Agriculture, the Defense Department, the U.N. Food and Agriculture Organization (FAO), the Organisation for Animal Health (OIE) and others detailed causes and effects of zoonotic diseases -- those that can pass from animals to people. (See related article.)
"An animal virus has spread across three continents, has become endemic in parts of Asia and Africa and now poses a worldwide epizootic [affecting many animals at the same time] threat," said Ambassador John Lange, the State Department's special representative on avian and pandemic influenza, during a July 16 AVMA session.
"Worse," he added, "the world is facing the risk that the highly pathogenic H5N1 virus could mutate and result in sustained and efficient human-to-human transmission -- in other words, a pandemic." (See related article.)
PERFECT MICROBIAL STORM
Over the past decade, a range of animal-generated human epidemics has stalked the globe -- hanta virus in the United States (1993), plague in India and deadly Ebola virus in Zaire (1994), West Nile virus in Africa (1999), Rift Valley fever in Africa (2000) and severe acute respiratory syndrome in Asia and Canada (2003).
Most recently, in 2005, researchers from CDC, the Johns Hopkins Bloomberg School of Public Health and the Army Health Research Center in Cameroon discovered two new retroviruses among central Africans who hunt nonhuman primates.
Human T-lymphotropic virus types 3 and 4 (HTLV-3 and HTLV-4), belong to a genus of viruses known to cause serious illness in people. The researchers said their findings show that people who are in contact with animals should be surveyed regularly for new infectious zoonotic diseases.
According to many epidemiologists, including Dr. Lonnie King, director of the new CDC National Center for Zoonotic, Vector-Borne and Enteric Diseases and dean of the Michigan State University College of Veterinary Medicine, 75 percent of emerging human diseases first arise in animals.
During an AVMA session, King said a new era of emerging diseases began 25 years ago and was described in a 2002 U.S. Institute of Medicine publication -- Microbial Threats to Health, Emergence, Detection and Response - as a group of factors "swirling and converging to create a perfect microbial storm."
He said this brings zoonotic pathogens that infect and kill people, emerge and re-emerge globally, and acquire characteristics like drug resistance.
Factors that contribute to emerging infectious diseases are microbial adaptation and change; host susceptibility to infection, climate and weather; changing ecosystems; economic development and land use; international travel and commerce; the breakdown of public health measures; poverty; and war and famine.
INTERNATIONAL EFFORTS
Around the world, organizations such as OIE, FAO and the World Health Organization (WHO) are embracing the “one health” concept.
Emerging diseases could have a devastating impact on international trade, Alejandro Thiermann, president of the OIE Terrestrial Animal Health Code Commission, told AVMA members, unless there is a movement away from traditional approaches to disease control and toward new, holistic prevention and control strategies.
Strategies to control emerging diseases will be more effective, he said, if authorities and veterinary services integrate their public and animal health objectives into a single strategy, coordinated by international standard-setting organizations such as OIE.
In September, OIE plans to release a new software tool, called Performance, Vision and Strategy (PVS), that nations can use to assess veterinary services using OIE international standards of quality and evaluation.
The FAO and OIE have launched an initiative called the Global Framework for the Progressive Control of Transboundary Animal Diseases -- those diseases that affect economies, trade or food security and that easily can spread to other countries.
The initiative, said Dr. Juan Lubroth, senior officer of the Infectious Disease Group for the FAO Animal Health Service, addresses issues related to tackling diseases at their source; improving capacity building; strengthening governance in veterinary services; and communicating the importance of livestock, wildlife and environment to human health.
Another program, the Global Early Warning and Response System (GLEWS), was launched in 2006 as a collaboration among FAO, OIE and WHO. It is the first joint early warning system established to predict and respond to animal diseases worldwide.
"From an animal health point of view," OIE Director-General Dr. Bernard Vallat said in a statement, "controlling contagious animal diseases in their early stages is easier and less expensive for the international community. In cases of zoonoses, this system will enable control measures that can also benefit public health."
For more information on U.S. and international efforts to combat avian influenza, see Bird Flu (Avian Influenza).
