INDEX
Readings
Programmatic Elements of the Emerging Infections Program of WHO
- Infrastructure development. Helping countries set up the systems to detect and contain diseases in their own countries.
- Practical solutions for disease prevention and control. What's feasible to do with the means we have today: the tools exist to prevent and control many infectious diseases, such as vaccines, antibiotics, and pesticides to control disease vectors. However, these are not always accessible or affordable to countries that need them most. We need to improve this situation.
- International Health Regulations. This legislation is being revised to facilitate reporting of infectious diseases of international public health importance. Minimizing disruption of international commerce (travel and trade), while encouraging reporting and response to contain infectious diseases, have been key elements of the revision.
- International public health security. Many industrialized countries, the US in particular, are afraid that infectious diseases from developing countries will enter the country and spread, causing both public health and economic problems. At the onset of the AIDS epidemic, legislative efforts in the US sought to "keep the disease out" of America. Emerging diseases can be seen as public health problems, affecting national security.
- Improved surveillance, monitoring and alert. Even more important than surveillance for industrialized countries is improved disease alert.
- Demonstrating the cost-effectiveness of using the tools we have available today to stop diseases.
Identifying Some Important Issues for the Program
Emerging diseases is really a catch phrase to get us into the problems of communicable diseases in general. Infectious diseases kill 17 million people a year, primarily in developing countries; these diseases will continue to be a problem for decades. Spectacular outbreaks, such as Ebola, can bring this important issue to the attention of our policy makers. With such attention, solutions are possible.
WHO/EMC working list:
- The global problem of infectious diseases, for a number of reasons already described.
- WHO's potential impact on the problem, including attracting funds to enable our work on the international level as well as in countries.
- We also raised the issue about globalization, the mobility of diseases and the effect on national public health security.
- We looked at factors contributing to the problem of emerging diseases as well as some possible solutions.
These elements are illustrated below.
Scope of the Problem
Infectious diseases remain a very important problem as we enter the 21st century. This [Slide] is probably the most convincing: a third of all adult deaths of the total 52 million deaths in the world each year are due to infectious diseases. The transmission types of these lethal diseases include animal-borne (the fewest), insect-borne, food- and water-borne, and person-to-person transmission.
Epidemics are expensive. New diseases occurring over the past year [Slide] included many emerging and re-emerging diseases. Not all of these diseases cause high mortality. However, when epidemics occur, countries must deal with them rapidly, sometimes at great cost, which diverts scarce resources from endemic disease control. In addition, epidemics can cause rapid, dramatic declines in trade and tourist revenues. Countries therefore go to great lengths to try to protect vital income by protecting trade and tourism.
Illustrating the Problem
Emergence and re-emergence of disease result from a number of factors, including changes in society and human behavior, environmental changes, urbanization and deterioration of public health measures. Each of these can have an important impact, shown by the examples below.
Social Change: Diphtheria in Eastern Europe
This [Slide] describes the consequences of civil disorder in Eastern Europe. These are the Newly Independent States, formerly comprising the USSR. Civil disorder and political change effectively destroyed public health protection from communicable diseases. In the early 1990s, with independence and a change in political structure, public health was no longer given priority in national investment. Diptheria vaccination (DPT) was interrupted, resulting in epidemics throughout these countries [Slide].
Behavioral Change: AIDS in Africa
This [Slide] shows how quickly an infectious disease, in this case AIDS, can spread across a continent. Much of this transmission is associated with behavior change. AIDS and sexually transmitted diseases have blossomed as urban migration and cultural mixing have changed traditional sexual mores in societies. Behavior patterns permit a sexually transmitted disease to amplify very rapidly; here there has been an increase from a less than 1% prevalence in 1980 to greater than 10% in 1994. In some countries in Africa AIDS now affects 30% of pregnant women. It's a very serious problem.
Environmental Changes, Deforestation: Meningitis
In addition, the environmental changes caused by deforestation play a role in increasing the spread of diseases. Climate change and changes related to the desert are enhancing the risk of epidemic meningitis in the sub-Sahara region. This [Slide] is a good example of desertification in Africa. You can see on Africa the A's and the C's. The A's represent meningococcal meningitis A. This is the epidemic form in Africa. Historically a group of sub-Saharan African countries form the "meningitis belt". Meningitis sweeps through these countries every 3 to 5 to 7 years in devastating epidemics. Recently Kenya, Tanzania and Uganda have begun to see epidemic meningitis as well. As the desert and dryness has extended, epidemics have occurred further and further south. This year, flooding may prevent this. This [Slide] shows the pattern of meningitis. There was an epidemic in 1996 followed in 1997 by a similar pattern.
Inadequate Public Health Measures: Yellow Fever
In the past 20 years there has been an increase in many other diseases due to inadequate or deteriorating public health measures. Yellow fever [Slide] has increased in Africa, and has become a serious problem, due to two things: First, immunization programs are no longer sustained, as yellow fever is no longer a vaccination priority. Second, mosquito control efforts have decreased throughout the world, including in Africa. If you look at Latin America, dengue is on the rise due to a lack of mosquito control: resources are no longer going into this problem.
Urbanization: Cholera
Rapid, uncontrolled urbanization in developing countries also contributes to the increase in infectious disease. Sanitation systems cannot keep up with populations moving into cities and the diseases that are associated with poor sanitation and unsafe water supply are the inevitable consequence. This [Slide] shows cholera, which entered the Americas in 1991. After 100 years of absence from the Americas, it returned in 1991; causing over 1.5 million reported cases and numerous deaths throughout the region.
Surveillance Systems Lacking: Ebola
Surveillance systems are an essential part of an effective public health infrastructure. Where they are lacking, the consequences can be critical. This [Slide] shows that the Ebola outbreak began in January, but it was not detected until it amplified in a hospital in April. It's important to realize that surveillance systems are in disrepair in both developing and industrialized countries. Where public health practices are poor, especially
Consequences as a Selling Point: HIV in Uganda, UK
Consequences are the key in convincing those people whom you need to convince to offer political and financial support for infectious diseases. The consequences of emergence and re-emergence of communicable diseases are: 1) high morbidity and mortality, 2) important economic impact, 3) disruption of usual endemic disease control activities and 4) detrimental interaction with other diseases.
For example, in 1989-1990, HIV/AIDS represented 44% of total population mortality in Uganda and, in the population 25-34 years of age, 89% of that mortality. Within a period of 10 years HIV has changed mortality patterns and is causing much human suffering. Both industrialized and developing countries, are susceptible to emerging and other infectious diseases and their impact. For example, BSE has caused severe economic disruption in the UK; one result of which has been a great increase in resources devoted to infectious disease control.
Infections Resistant to Antimicrobials
The spread of infections resistant to antimicrobial agents affects both developing countries and the industrialized world. Prescribing and infection control practices of health workers and hospitals, medication taking practices of patients, and antibiotic availability policies of national health systems all contribute to the basic problem of resistance. The CDC demonstrated that mortality doubled in persons who were infected with resistant infections compared to those who had non-resistant infections. Many countries in Africa can no longer treat gonorrhea or many other infectious diseases because the antibiotics which are affordable are no longer effective; quinalones and the second and third generation antibiotics are out of the price range of both the private and government sectors in many countries.
Economic cost of HIV in Thailand
This [Slide] showing the impact of HIV/AIDS in Thailand illustrates the cost of emergent infections. Thailand estimates that AIDS costs the country 2.2 billion dollars a year, and that by the year 2000, they will have spent or lost 8.7 billion dollars due to HIV/AIDS.
Other Issues of Globalization -- Travel and Tourism in Thailand
Infectious diseases travel very easily
[Slide]. These are two clones of multi-resistant Streptococcus pneumoniae, both of which were first isolated in Spain and later isolated within a period of two months throughout the world, a very rapid spread. The Thai government and WHO found that 11% of tourists carried with them some type of infectious disease. These
[Slide] are the types of diseases among 477 tourists exiting Thailand
Misuse of Antibiotics
Misuse of antibiotics also contributes to resistance. This data [Slide], again from Thailand, showed that 36% of infections were treated with an antibiotic when an antibiotic wasn't indicated. These are good results compared to what Canada found; 50% of their antibiotics are used in persons who don't have bacterial infections, according to one study. This issue was an important one which WHO/EMC pulled in to address.
The Use of Antimicrobials in Animals
Antimicrobial resistance is augmented by animal husbandry practices, spraying of crops with antibiotics to prevent diseases in apples and pears. Persistence of Salmonella in the Netherlands is seen here in pig isolates [Slide]. The trend over the past 15 years has been an increase in resistance in animals; humans in that country exhibit the same trend [Slide]. Exposure comes from environmental routes as well. Last year in the US, 300,000 pounds of antimicrobials were sprayed indiscriminately from airplanes onto fruit trees.
Identifying the Main Issues: Eradication, Legislation and Good Health Practices
The three strategies that have traditionally been used to prevent or control infectious diseases have been eradication campaigns, legislation and good public health practices.
Disease Eradication: Smallpox
Eradication is a very powerful approach, and it's easy to convince legislators -- the US Congress, for example -- that eradication is important if you can show them what it will do and how much money it will save. The impact of smallpox eradication has probably been the most studied of any infectious disease as regards cost-effectiveness.
In 1967, 30 years ago, over 1.5 million people in the world died from smallpox. The annual cost of this disease to the world was $1.4 billion. This was in lost life, lost economic input, cost of vaccination and the side effects from vaccinations, as vaccinations were not denied. The cost of the eradication program, which continued from 1967 to 1979, was $300 million. The US in 1967 (the year smallpox eradication began) had estimated that the disease cost the country $92.8 million from the cost of the vaccine, from the nine deaths that occurred as a result of vaccination and the four permanent disabilities associated with the vaccine. Having looked at all these factors, when we look at the disappearance of this disease and the need no longer to vaccinate, the US today saves the equivalent of its investment in the smallpox eradication program every 26 days. This is a powerful argument for talking with the people who are making decisions on funding and policy.
Conditions for Eradication
Not every infectious disease can be eradicated. There must be the following characteristics: 1) the disease must have no reservoir other than humans; 2) the patient must clear the infection and develop solid immunity; 3) intervention must be affordable, effective and practical to administer; 4) the disease must be sufficiently important to warrant the effort; and 5) interruption of transmission must be demonstrated in those countries where it is most feasible first, before beginning to work on developing country issues.
Polio as a Case for Eradication
Polio is gone from the Americas. It is estimated that by 2002, polio will be gone from the world. We can look at another disease that has been eradicated. The US has shown the cost savings for eradicating smallpox and no longer requiring vaccination. They vary, but it is in the billions of dollars that the US will save per year since smallpox has been eradicated from the world.
Criteria for Eradicability
The first criteria for eradicability was that it cannot have a reservoir other than man. That is because trying to wipe out all rodents that may have fleas that could carry bubonic is an impossibility. Certain interventions are biologically impossible. Biologic Feasibility, i.e. a human reservoir rather than another vector is in favor of eradicability.
Eradication - A Policy Perspective
Eradication is appealing to donors because it presents definite goals for achievement. In the US, policy change occurs, in part, through a process of congressional hearings.
Securing a Hearing on Capitol Hill
In 1996, a hearing was scheduled with Senator Casovan presiding, about Emerging Infections. The Senator is very interested in the issue of infectious diseases. This was the entry point into Congress that led into two other hearings, one in the House and one in the Senate, last year, when we raised many of these issues. Security issues figured strongly in these hearings. For example the vector Aedes Aegypti ranges into the US as far north as Washington DC in the summer, bringing the potential for Yellow Fever and Malaria transmission. This really attracted their attention. Other things that attracted their attention were antibiotic resistance, and the suggestion that maybe they wouldn’t be able to have their grandchild treated for a simple ear infection because antibiotics would no longer be effective. Just communicating a few pertinent messages like that with Congress has resulted, through the efforts of Senator Lahey, who is the minority in the Senate, in an add-on to USAID’s budget of $50 million. This add-on is to focus on four issues, and that was surveillance, Malaria, Tuberculosis and antimicrobial resistance. This is a beginning with that $50 million.
Next month in Washington, there is a hearing on eradication because there are other diseases besides polio. There’s leprosy, which is going to be eliminated, there’s Chaga's disease, and there’s Guinea Worm, which is close now, Lymphatic filariasis, which can probably be gotten rid of. So next month, there’s a new series of hearings beginning on Capitol Hill, in which we’ll push the issue of eradication and the cost effectiveness that could result. So the issues, getting the issues out and getting them discussed are very important.
Biological Warfare Concerns
There’s the question of maintaining immunity when you eradicate some of those diseases or the possibly of diseases which have been suppressed, emerging.
Even more, when you have a sitting duck population, biological warfare using one of these agents is very powerful. We officially know that there is Small Pox virus in two laboratorys. But the same is true for polio, and even more important for polio when polio is eradicated, because that virus is everywhere. The wild polio virus is everywhere, and when polio is eradicated, are the defense and the Congress going to accept not vaccinating populations? Is the public going to accept that? Those are the questions. Small Pox came at the right time. I said yesterday that it came before HIV, we could still use Small Pox vaccination, and it came when people weren’t thinking about biological warfare and other issues, and eradication today is going to be an issue. It won’t be an issue for things like leprosy, but for these really easily.
Controlling Infectious Diseases through Legislation
The second disease policy response to infections is attempts at legislation. Since 1374, there have been attempts. In 1374, Venice for the first time created legislation which quarantined persons with plague and which kept ships out in the harbor and wouldn’t let ships come in because they didn’t want the rats to come in carrying the plague. So any ship that had the plague was quarantined, and all ships were kept out in the harbor and landing vessels brought in the supplies after they were de-ratted.
International Health Regulations
Since that time, there have been various national and international efforts, until 1969, when what we today call the International Health Regulations were developed in Geneva at WHO. Today, these are the sole legislation requiring reporting of certain diseases. Their purpose in 1969 was to ensure maximum security against the international spread of diseases with minimum interference in world travel and trade. The goals were to detect and reduce or eliminate the sources from which infections spread to airports and sea ports, eliminate breeding sites for vectors and reservoirs such as mosquitos and rats, that could allow disease transmission. It also required reporting of four (now three) infectious diseases: cholera, plague and yellow fever.
How effective are these Regulations?
The regulations were set up to provide maximum security and minimum disruption. Yellow fever vaccination is one of the recommendations most consistently followed. People are vaccinated against yellow fever before they travel, as people who have brought yellow fever back to the US have been non-vaccinated travellers. (Last year there was an imported case in the US and in Switzerland, both cases had not been vaccinated.) The spread of plague has certainly been controlled. Containerization, inspection of ships and ports has reduced the rat problem and stopped plague importation. But the spread of cholera has not been prevented. Cholera is now endemic in over 50 countries, and continues to have epidemic occurrence in certain areas.
Reporting infectious diseases still causes international disorder and stigmatization. When a country reports certain diseases, there are immediate trade barriers. When cholera hit Peru in 1991 [Slide], the US restricted seafood imports. There was a $70 million loss in tourist revenue and a $700 million loss in trade in the first year after the cholera epidemic. We are witnessing the same problem now in east Africa where cholera is endemic. Several outbreaks came to media attention, resulting in a ban on African freshwater fish into Europe. This ban is illegal according to the International Health Regulations.
Reporting Diseases by Syndrome
The working group on revising the International Health Regulations is testing syndromic reporting using precise case definitions. These are currently being field tested. The syndromes are defined based on the list of epidemic-prone infectious diseases. The revised regulations are still in draft format, and criteria for field-testing are under development. The five acute syndromes are: 1) respiratory, 2) diarrheal, 3) neurological, 4) hemorrhagic, and 5) unrecognized syndrome.
Monitoring will focus on clusters of disease which have high mortality and are spreading rapidly in a country, thus posing a potential threat internationally. These cover most of the infectious diseases of international concern.
Proposal for Revised International Health Regulations
The new regulations will include descriptions of best public health practices with a goal of developing into a convention. A convention is binding on signatory countries. The convention would require that countries use mono-inject syringes and adhere to certain standards to stop the spread of disease. It will include descriptions and practices that are inappropriate- this is important because there are many such practices. There will be a practical handbook and 24 hour availability for assistance.
There will be an international alert and response system. WHO will work with all 191 countries in the application of these norms, showing what should and should not be done. With pressure by countries, a new understanding of how the international community should react to these diseases will emerge, putting pressure on policy makers to take appropriate action. Changing the culture internationally could make the regulations contribute to the important global monitoring system.
Field testing began in November, and picked up an outbreak in Latin America which came to the attention of national authorities. Reported as a syndrome very quickly to WHO, it turned out not to be an infectious disease. We also picked up a syndrome in Amazonia, again coming in rapidly: this was yellow fever.
These Issues Will Continue
Infectious diseases will continue, antimicrobial resistance will stay and travel and globalization will continue. But strong surveillance will permit early detection and response, and good public health practices will prevent and control diseases. Education will slow microbial resistance and help control disease. Finally, we have to be sure that there is a continued research and development base to provide new tools.
A Four Part Program—WHO Initiative
After identifying the issues and discussing them within the program, we took the vision and translated it into a four part program:
Global monitoring and alert
Global information access
Strong national surveillance and control
International preparedness
We then developed an objective for each of those. The first was to strengthen WHO information networks on infectious (including zoonotic diseases) to ensure early detection of threats to international public health. WHO has strengthened five different systems: the International Health Regulations, the WHO Collaborating Centers, specialized laboratories for viral, bacterial and zoonotic diseases. We have in our division over 200 centers collaborating with us, monitoring specimens for disease detection.
We also set up resistance monitoring networks
[Slide] because developing countries didn't have them. We decided that we needed to investigate rumors in a systematic manner and to strengthen some of the active surveillance networks maintained by WHO. The regulations are being revised and field tested. In 1999 they will go to the World Health Assembly for approval. Countries will have six months to disagree and withdraw as signatory. If they have not done so within that time, countries adhere to the regulations.
Enforcement
Enforcement will strengthen the regulations. If a country refuses to report a disease (known to WHO from our collaborating centers), WHO will ask the country to state why it did not comply. The response goes to the WHO committee on international surveillance, the governing body for the regulations. If they decide that the country was not justified in not reporting the disease, they will recommend to the Director-General that Article 7 of the WHO Constitution be invoked-under which a country's vote can be taken away. In these areas, WHO is working with the World Trade Organization and the Codex Alimentarius (which governs food importation and commerce).
Laboratory System as Global Monitoring Alert
The second system for monitoring and alert is our system of laboratories monitoring viral, bacterial and zoonotic diseases. WHO laboratories, spread worldwide, are national and regional centers of expertise. They report directly to WHO when a disease is identified. This [Slide] is the collaborating system for hemorrhagic fevers. WHO's laboratories (over 200) are geographically well placed throughout the world. The laboratories in the south require strengthening to improve geographic self-sufficiency.
The Antimicrobial Resistance Program
The third system is for antimicrobial resistance. The concern here is to strengthen national laboratory networks monitoring resistance. At the national level, information obtained from monitoring has to be translated into policy. When we work with our laboratories, we also include a national policy meeting to assist the ministries of health to understand how to translate monitoring results into action. In this effort we have joined with the drug action program at WHO, which recommends the world list of essential drugs.
Outbreak Verification System
The fourth system is the WHO/EMC outbreak verification system. We take information from many sources (including the Internet and other reports) and compile a list of reported outbreaks. Each one is considered pending while it is being investigated through our network of contacts in countries. Once confirmed, reports are published on Disease Outbreak News on the WWW.
Networks
The fifth consists of specialized surveillance networks, including influenza and rabies. We have built interactive Web interface reporting mechanisms so that countries with a code can enter reports in a standard format, and send them directly to WHO. This is
[Slide] FluNet for influenza; this is Switzerland's data, they have entered this data directly on the net. This information it is displayed as maps or graphics giving a picture of influenza activity around the world.
Conclusion
This is how we have set up the program. The elements are global monitoring and alert; global information access; national surveillance and control; and international preparedness-making sure the norms and guidelines (including case definitions and surveillance standards) are available and that countries are prepared to act to contain diseases. An important challenge remains: to be sure that the resources remain in infectious diseases, and that we don't lose them because there are new priorities. This is your job, to make sure that the resources stay in public health and infectious diseases so that we can continue to make progress in infectious disease control.
Readings:
Heymann, D.L. "Infectious Diseases: Still a Threat at the Turn of the Century."
Heymann, D.L.. "Challenges - Reemerging pathogens and diseases out of control." The Lancet, Vol. 349, June 1997. (summary)
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