Embed Size (px)
DESCRIPTION
Emerging Infections, Reemerging Infections
Citation preview
Dr.T.V.Rao MD
Dr.T.V.Rao MD 1
Infectious disease is one of the few genuine adventures left in the world. The dragons are all dead and the lance grows rusty in the
chimney corner . . . About the only sporting proposition that remains unimpaired by the relentless domestication of a once free-living human species is the war against those ferocious little fellow creatures, which lurk in the dark corners and stalk us in the bodies of rats, mice and all kinds of domestic animals; which fly and crawl with the insects, and waylay us in our food and drink and even in
our love.
- (Hans Zinsser,1934 quoted in Murphy 1994)
Dr.T.V.Rao MD 2
The discovery of disease-causing pathogens is an
important activity in the field of medical science, as many viruses, bacteria protozoa, fungi, helminthes and prions are identified as a confirmed or potential pathogen. A Center for Disease Control program begun in 1995 identified over a hundred patients, with life threatening illnesses which were considered to be of an infectious cause, but could not be linked to a known pathogen. The association of pathogens with disease can be a complex and controversial process, in some cases requiring decades or even centuries to achieve total control on the etiological agents.
What is a Emerging Infectious Disease
Dr.T.V.Rao MD 3
EMERGING INFECTIOUS DISEASES
Microbes and vectors swim in the evolutionary stream, and they swim faster than we do. Bacteria reproduce every 30 minutes. For them, a millennium is compressed into a fortnight. They are fleet afoot, and the pace of our research must keep up with them, or they will overtake us. Microbes were here on earth 2 billion years before humans arrived, learning every trick for survival, and it is likely that they will be here 2 billion years after we department. (Krause 1998).
Dr.T.V.Rao MD 4
Direct economic impact of selected infectious disease outbreaks, 1990-2003
Heymann DL. Emerging and re-emerging infections. In Oxford Textbook of Public Health, 5th ed, 2009, p1267.
Dr.T.V.Rao MD 5
The World Health Organization warned in its 2007
report that infectious diseases are emerging at a rate that has not been seen before. Since the 1970s, about 40 infectious diseases have been discovered, including SARS, Ebola, Avian flu, and Swine flu. With people traveling much more frequently and far greater distances than in the past, the potential for emerging infectious diseases to spread rapidly and cause global epidemics is a major concern.
WHO Warns the Trends
Dr.T.V.Rao MD 6
Many are Zoonotic Infections.
Many emerging diseases arise when infectious agents in animals are passed to humans as zoonosis. As the human population expands in number and into new geographical regions, the possibility that humans will come into close contact with animal species that are potential hosts of an infectious agent increases.
Dr.T.V.Rao MD 7
Emerging zoonotic diseases have potentially serious
human health and economic impacts and their current upwards trends are likely to continue. Examples are avian influenza, Bovine Spongiform Encephalitis (BSE) and the Nipah virus. Some of the "lingering" zoonosis are re-emerging in some regions, although they seem to attract less public awareness. Brucellosis, dog rabies and parasitic diseases such as cysticercosis/taeniasis and echinococcosis/hydatidosis for example.
Emerging Zoonosis
Dr.T.V.Rao MD 8
Climate change Promotes Emerging Infections
Climate change is increasingly becoming a concern as a factor in the emergence of infectious diseases. As Earth's climate warms and habitats are altered, diseases can spread into new geographic areas.
Dr.T.V.Rao MD 9
How HIV Emerged
The example of an emerging infectious disease that can be attributed to human practices is HIV. It is thought that humans were first infected with HIV through close contact with chimpanzees, perhaps through bush meat hunting, in isolated regions of Africa. It is likely that HIV then spread from rural regions into cities and then internationally through air travel
Dr.T.V.Rao MD 10
Previously undetected or unknown infectious agents
Known agents that have spread to new geographic locations or new populations Previously known agents whose role in specific diseases has previously gone unrecognized. Re-emergence of agents whose incidence of disease had significantly declined in the past, but whose incidence of disease has reappeared. This class of diseases is known as re-emerging infectious disease
Emerging infections can be caused by:
Dr.T.V.Rao MD 11
Emerging infectious diseases are caused by
new or previously unrecognized microorganisms (. Although the term became part of the journalist’s lexicon in the 1990s, emerging infectious diseases have long been recognized as an important outcome of host-pathogen evolution. Because emerging infections may have severe public health consequences, they are a focus of both the popular press and scientific research.
Emerging Diseases are New to our knowledge
Dr.T.V.Rao MD 12
The changing landscape of infectious
diseases over the past 2 decades has astounded the medical PROFESSIONALS and the PUBLIC. Emerging pathogens that cause new diseases (e.g., severe acute respiratory syndrome–associated coronavirus [SARS-CoV]), newly recognized microbial agents of known diseases (e.g., human metapneumovirus), and rapidly evolving pathogens (e.g., influenza viruses) all contribute to this seismic shift
Infectious diseases are not Static but New are Emerging
Dr.T.V.Rao MD 13
Respiratory Infections are Major Threat
Acute respiratory infections are, globally, the major cause of mortality in children 5 years of age. The advent of diagnostic platforms suited to surveillance as well to clinical application will reduce the morbidity and mortality of respiratory
Dr.T.V.Rao MD 14
Dr.T.V.Rao MD 15
Factors Contributing to Emerging Infections
Several factors contribute to the emergence of new infectious diseases. They include the increasing growth and mobility of the world‟s population, overcrowding in cities with poor sanitation, massive food preparation and international distribution,
Dr.T.V.Rao MD 16
Dr.T.V.Rao MD 17
Changes in human behavior, food habits and environment
Unsanitary food preparation, exposure of humans to disease vectors and reservoirs, and ecological changes that alter the composition and size of insect vectors and animal reservoirs.
Dr.T.V.Rao MD 18
Some emerging infections are caused by microbes that originate in nonhuman vertebrates. Hantavirus pulmonary syndrome was first noted in the Four Corners area of New Mexico in 1993. The disease is caused by Sin Nombre virus, which is endemic in the deer mouse (Peromyscus maniculatus).An increase in the deer mouse population might have been a factor. In 1992–93, abundant rainfall produced a large crop of piñon nuts, which are food for both humans and the deer mouse. As the mouse population rose, contact with humans increased.
Animal origins of Emerging Infections
Dr.T.V.Rao MD 19
Animal origins of Emerging Infections – Hanta Virus
The virus is excreted in
mouse droppings, and contaminated blankets or dust from floors provided opportunities for human infection. Because humans are not the natural host for Sin Nombre virus, the human disease is rare.
Dr.T.V.Rao MD 20
Emergence of Lyme disease,
The emergence of Lyme disease, t he infection has probably been present in North America for millennia, but it was only in the 20th century that conditions in the northeastern US changed to favor the propagation of Lyme disease.
Dr.T.V.Rao MD 21
Dr.T.V.Rao MD 22
Some emerging infectious diseases are
caused not by new pathogens, but by the re-emergence of microbes that had been successfully controlled. The mosquito-borne dengue virus was shown in 1903 to be the causative agent of dengue fever, a disease accompanied by fever, rash, and arthralgia. Fifty years later, a new disease caused by the virus, dengue hemorrhagic fever, was identified in Southeast Asia
Age old infections can be Reemerging
Dr.T.V.Rao MD 23
Pan American Health Organization
The Pan American Health Organization led efforts to eradicate the mosquito vector of dengue virus, Aedes aegypti, from most of Central and South America. As a consequence, dengue fever and dengue hemorrhagic fever were largely eliminated from all but Southeast Asia. Unfortunately, the mosquito-eradication programs ended in the 1970s, leading to reinfestation of the Americas.
Dr.T.V.Rao MD 24
Dengue – A Reemerging Infection
Dengue virus has been reintroduced into the Caribbean, the Pacific, Australia, and the Indian subcontinent and has appeared for the first time in China, Venezuela, and Brazil. Intercontinental transport of car tires containing mosquito eggs has been implicated in the spread of the virus.
Dr.T.V.Rao MD 25
Millions are affected with Dengue
Currently there are
an estimated 100 million cases of dengue fever and several hundred thousand cases of dengue hemorrhagic fever each year, and 2.5 billion people are at risk for infection. Dr.T.V.Rao MD 26
Unfulfilled Gaps to Molecular Methods
In recent years, there has been substantial progress in applying molecular biologic advances to respiratory virus diagnosis nonetheless, a major gap has been the lack of a cost-effective, systematic way to identify the causes of respiratory diseases in populations.
Dr.T.V.Rao MD 27
Drug Resistant Pathogens are Emerging
The problematic as the threat of emerging infectious diseases is the emergence of drug-resistant pathogens, which can turn a conquered microbe into a new threat. Low-cost, common antibiotics can no longer clear infections of Escherichia coli, Neisseria gonorrhea, Pneumococcus, Shigella, and Staphylococcus aureus.
Dr.T.V.Rao MD 28
Dynamics of Modern Life Contributed
The cost and length of
treatment of many common diseases are increased, or infections may be refractory to treatment. The changing dynamics of a growing population children‟s day care centers, and the overuse of antibiotics, both in humans and in the food chain, have contributed to the emergence of drug-resistant microbes.
Dr.T.V.Rao MD 29
Drug Resistant Malaria a grave threat to Developing Countries
The emergence of resistance of Plasmodium falciparum to chloroquine, once a mainstay in the prevention of malaria, has led to a global resurgence of this disease
Dr.T.V.Rao MD 30
Increasing Human Comfort and Changing Life styles too Contribute
Humans are always
providing new ways to meet new pathogens. Air travel, dam construction, hot tubs, air conditioning, blood
transfusion, deforestation, day care centers, and urbanization
are some of the technological and social changes that influence the spread of microbes.
Dr.T.V.Rao MD 31
Need for Antibiotic Stewardship
While rising rates of antimicrobial resistance are driving many institutions to adopt antimicrobial stewardship programs, many are finding the principle difficult to put into practice. Some physicians from across the medical spectrum ignore recommendations to reduce unnecessary use of antimicrobials.
Dr.T.V.Rao MD 32
Dr.T.V.Rao MD 33
Ever Increasing Population in Developing Countries
Most importantly, growth of the human population continues, providing interactions with other humans and the environment on an unprecedented scale, and ensuring the propagation of new diseases.
Dr.T.V.Rao MD 34
One Health
One Health is the collaborative effort of multiple disciplines – working locally, nationally, and globally – to attain optimal health for people, animals, and our environment.
Dr.T.V.Rao MD 35
Goal 1: Develop, implement and sustain a national strategy for improved public health based on the principles of One Health Goal 2: Create national awareness within the veterinary and medical professions; the broad scientific community; government institutions; the political leadership; and the general public of the power of One Health to improve the health of people, animals and the environment Goal 3: Illustrate the value of implementing One Health principles through specific Demonstration Projects Goal 4: Extend the One Health Initiative to the international community to achieve tangible improvements in global health
One Health Initiative (OHI) has four long-term goals
Dr.T.V.Rao MD 36
Unfulfilled Gaps to Molecular Methods
In recent years, there has been substantial progress in applying molecular biologic advances to respiratory virus diagnosis nonetheless, a major gap has been the lack of a cost-effective, systematic way to identify the causes of respiratory diseases in populations.
Dr.T.V.Rao MD 37
We can Track very Fast
Emerging infections can be tracked by the hour on the Internet (ProMED-mail, (www.promedmail.org) and in scientific journals (e.g., Emerging Infectious Diseases).
Dr.T.V.Rao MD 38
Emerging Infections Network
In 1995, the CDC granted a Cooperative Agreement Program award to the Infectious Diseases Society of America (IDSA) to develop a provider-based emerging infections sentinel network: the Emerging Infections Network (IDSA EIN).
Dr.T.V.Rao MD 39
How Emerging Infectious Diseases Network works
The Emerging
Infections Network (EIN) is a provider-based sentinel network designed to help the public-health community detect trends in emerging infectious diseases.
Dr.T.V.Rao MD 40
Emerging Infections Network Works
IDSA EIN has evolved into a flexible sentinel network composed of over 1,100 infectious disease specialists primarily from North America, with some global members. The overarching goal of the EIN is to assist CDC and other public health authorities with surveillance for emerging infectious diseases and related phenomena.
Dr.T.V.Rao MD 41
Detect new or unusual clinical events;
Identify cases during outbreak investigations;
Gather information about clinical aspects of emerging infectious diseases;
Help connect members to the CDC and other public health investigators; and
Develop new methods for gathering epidemiological and clinical information.
The Specific goals of the EIN are to:
Dr.T.V.Rao MD 42
STRATEGIES TO REDUCE THREATS
IMPROVE GLOBAL RESPONSE CAPACITY
WHO
National Disease Control Units (e.g. USCDC, CCDC)
IMPROVE GLOBAL SURVEILLANCE
Improve diagnostic capacity (training, regulations)
Improve communication systems (web, e-mail etc.)
Rapid data analysis
Develop innovative surveillance and analysis strategies
Utilize geographical information systems
Utilize global positioning systems
Utilize the Global Atlas of Infectious Diseases (WHO) Dr.T.V.Rao MD 43
STRATEGIES TO REDUCE THREATS
USE OF VACCINES Increase coverage and
acceptability (e.g., oral)
New strategies for delivery (e.g., nasal spray administration)
Develop new vaccines
Decrease cost
Decrease dependency on “cold chain”
NEW DRUG DEVELOPMENT
Dr.T.V.Rao MD 44
STRATEGIES TO REDUCE THREATS
DECREASE INAPPROPRIATE DRUG USE Improve education of clinicians and public
Decrease antimicrobial use in agriculture and food production
IMPROVE VECTOR AND ZOONOTIC CONTROL Develop new safe insecticides
Develop more non-chemical strategies e.g. organic strategies
BETTER AND MORE WIDESPREAD HEALTH EDUCATION (e.g., west Nile virus; bed nets, mosquito repellent)
Dr.T.V.Rao MD 45
ROLE OF THE PUBLIC HEALTH PROFESSIONAL
Establish surveillance for: Unusual diseases Drug resistant agents
Assure laboratory capacity to investigate new agents (e.g., high-throughput labs)
Develop plans for handling outbreaks of unknown agents
Inform physicians about responsible antimicrobial use
Dr.T.V.Rao MD 46
ROLE OF THE PUBLIC HEALTH PROFESSIONAL
Educate public about Responsible drug compliance
Emergence of new agents
Infection sources Vector control
Malaria prophylaxis
Be aware of potential adverse effects of intervention strategies
Anticipate future health problems
Promote health and maximize human functional ability
Dr.T.V.Rao MD 47
Our Vision should look for Our Survival
Human population growth, technological advances, and changing social behaviors lead to the selection of new microbial pathogens. Antimicrobial drugs, vaccines, diagnostics, and treatments for emerging infectious diseases must be developed. The selective forces that drive the emergence of new infectious diseases, and the implications for our survival, are just beginning to be understood.
Dr.T.V.Rao MD 48
Role of Microbiology
Crucial link The importance of
Microbiology laboratories rests with prompt identification and reporting can cure with simple remedies, as most of the emerging infections respond to several drugs and choice lies with optimal selection based on Antibiograms, as resistance is not a menace with emerging, newer and uncommon isolates
Dr.T.V.Rao MD 49
Up gradation of Diagnostic Microbiology Laboratories a Must
The modern generation of Microbiologists should be familiar with Identification of the Microbes with newer generation of Technological advances.
Dr.T.V.Rao MD 50
Share your Observations on
www
Today sharing the knowledge on Microbes through World Wide Web (WWW) helps for faster dissemination of Knowledge and many lives in the Developing world can be saved
Dr.T.V.Rao MD 51
Research on Emerging Infectious Disease Agents
The development of
vaccines and antimicrobial drugs and the remarkable eradication of smallpox had created hope that infectious diseases could be controlled or even eliminated. However, the current realization that infectious diseases continue to emerge and re-emerge (including the possibility of bioterrorism), underscores the challenges ahead in infectious disease research.
Dr.T.V.Rao MD 52
Caution …. Donot discard Unfamiliar bacteria in the
routine Diagnostic work
Many important pathogens both unfamiliar, emerging and reemerging are discarded without much consideration and review.
Be wise to consult a colleague and some one who is more familiar
Dr.T.V.Rao MD 53
Need for global help to Developing countries
Commitment to technology transfer and global collaboration is essential if we are to have the agility required to keep pace with emerging infectious diseases. Pathogen surveillance and discovery can promote global interaction via collaborations on matters that know no national or political boundaries but simply reflect our common goals.
Dr.T.V.Rao MD 54
Update your Knowledge from
CDC
Dr.T.V.Rao MD 55
Follow me for More Articles of Interest on Infectious Diseases
Dr.T.V.Rao MD 56
Created by Dr.T.V.Rao MD for „e‟ learning resources for Medical and
Public Health Personal in the Developing World
Dr.T.V.Rao MD 57
