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Institute of Medicine (US) Forum on Emerging Infections; Davis JR, Lederberg J, editors. Emerging Infectious Diseases from the Global to the Local Perspective: A Summary of a Workshop of the Forum on Emerging Infections. Washington (DC): National Academies Press (US); 2001.

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Emerging Infectious Diseases from the Global to the Local Perspective: A Summary of a Workshop of the Forum on Emerging Infections.

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3Emerging Infections in Africa


As a region, Africa is characterized by the greatest infectious disease burden and, overall, the weakest public health infrastructure among all regions in the world. Frequently, vertically oriented disease surveillance programs at the national level and above in Africa often result in too much paperwork, too many different instructions, different terminologies, too many administrators, and conflicting priorities. Streamlined communications, strengthened public health surveillance, the use of standard case definitions, criteria for minimum data requirements, and emphasis on feedback through integrated forms, as well as research and training opportunities, are among the important tools available to improve the situation. Yet, efforts to establish fully more effective public health infrastructures may take a period of years to decades.

The aim in Africa is to identify a group of priority diseases categorized as epidemic- prone diseases, diseases targeted for eradication or elimination, and other diseases of public health importance. The challenge will be to integrate surveillance and epidemic preparedness and response activities for these priority diseases, especially when there are weakened ministries of health. Bilateral and multilateral agreements, as well as partnerships with nongovernmental organizations and commercial interests, are among the means being explored to strengthen disease surveillance and response activities, to transfer epidemiological and microbiological skills, and to facilitate timely recognition of these disease outbreaks and their control. Among the promising roles provided by global disease surveillance is the integration of new technology tools in resource-poor environments, such as in sub-Saharan Africa, for the development of an early-warning system based on remotely sensed (satellite) data for Rift Valley fever surveillance.

At a time when increasing attention is focused on many of the recently emerging infections (monkeypox virus, Rift Valley fever virus, filiovirus, Vibrio cholerae O139, and penicillin-resistant Streptococcus pneumoniae) and reemerging infectious diseases (malaria, tuberculosis, yellow fever, and trypanosomiasis) continually incubating and bursting forth from Africa, major gaps exist in surveillance, research and training programs, and the availability of qualified professionals concerned with infectious diseases in Africa. The infrastructure and level of support for surveillance, research, and training on emerging infectious diseases in Africa are extremely limited. There is a shrinking number of trained infectious disease specialists in Africa, from the community health worker, to the laboratory technician, to professionals in the specialized professions of virology, microbiology, medical entomology, epidemiology, and public health. The latter point was emphasized at the workshop on which this report is based, as none of the African scientists invited to make presentations at the workshop were available owing to exigent schedules and demanding workloads for the qualified few, in addition to difficulty in obtaining government permission to travel and technological obstacles to effective communication. The challenge ahead will be to broaden the base of qualified personnel at all levels in Africa.



, M.D.


Chief, Meningitis and Special Pathogens Branch, National Center for Infectious Diseases, Centers for Disease Control and Prevention, United States

A project developed jointly by the World Health Organization (WHO), the African Regional Office of WHO, the Centers for Disease Control and Prevention (CDC), and the U.S. Agency for International Development (USAID) aims to improve the well-being of the approximately 600 million people currently residing in the 46 member states of the African Regional Office of WHO. The project implements integrated infectious disease surveillance and improved epidemic preparedness and response.

On September 2, 1998, the African Regional Office adopted a strategy for integrated epidemiological surveillance of diseases as a regional approach to control communicable diseases and urged its member states to evaluate surveillance and laboratory support, as well as to implement the regional strategy for integration as it was developed.

The response to smallpox has been used as a model for contemporary measures. Until the late 1960s, 10 to 15 million cases of smallpox occurred yearly and the overall smallpox mortality rate at a global level was 15 to 20 percent. Although the economic costs of the eradication effort were sizable, the benefits in terms of economics were similarly tremendous. Even for the smallpox initiative, which was relatively well funded, it took 2 years to establish effective surveillance in most areas.

The smallpox response model has been used, for example, to respond to meningitis in the sub-Saharan meningitis belt, where periodic, irregular, and large meningitis epidemics occur. A vaccine against meningitis is available, but it is ineffective in young children, so emergency mass campaigns are used to control the disease. Over the last decade, WHO, USAID, and other organizations have developed surveillance-based thresholds for the initiation of mass vaccinations, accompanied by appropriate laboratory confirmation. On the basis of some model data obtained over the last 10 years, it is known that a rapid response is essential for the effectiveness of this strategy.

Data from Ghana gathered in 1996 and 1997 suggest that about 5,000 cases of meningitis and 304 deaths were prevented by the reaction of the Ghana Ministry of Health. If 85 percent vaccine coverage could have been achieved within 1 week after the epidemic was identified, substantially more cases and deaths could have been avoided. These data provide an example of the effective use of surveillance data to detect a problem and also to assess the effectiveness of a public health response to that problem.

The difficulties with surveillance in Africa are well known. In the context of the multiple epidemics that have been recognized over the past decade, numerous assessments of surveillance systems have revealed problems essentially across the board.

Individuals who are part of vertically oriented programs at the national level and above try to communicate with district officials and health facilities at the local level, resulting in too much paperwork, too many different instructions, different terminologies, too many administrators, and conflicting priorities.

The time is right to move toward integrated disease surveillance and epidemic preparedness and response in Africa. A number of important things that leverage the opportunities for success in this area are happening. One of the first efforts was streamlining of the communication and conduct of public health surveillance, with the use of standard case definitions, minimum data requirements, and an emphasis on integrated forms, feedback, and training. No single approach is likely to fit all countries, yet WHO is committed to providing support to all of its member states.

The next major step was to identify a group of priority diseases. A group of 18 diseases was categorized. These included epidemic-prone diseases, diseases targeted for eradication or elimination, and other diseases of major public health importance. If effective surveillance is broken down into 10 elements, multiplied by 18 priority diseases, and combined with four levels of the health system, designing an ideal system becomes complex. All of these units require some technical input, and all must accommodate the other diseases included in the surveillance effort.

The transition to integration is happening. Most countries have existing systems for some disease surveillance. Recently, polio eradication has become a major focus of new efforts, which should establish an infrastructure for future responses. Surveillance for cholera, meningitis, neonatal tetanus, typhoid fever, yellow fever, dysentery, malaria, and measles is needed at various levels in many countries. Some countries, such as Tanzania, are requesting help with integrated disease surveillance. As development of public health infrastructures progresses over a period of years to decades, additional diseases can be added to the system. Currently, 15 polio laboratories are functioning, and 7 bacterial meningitis laboratories have been established, as have 5 diarrheal disease laboratories and 2 laboratories that are monitoring antimicrobial resistance.

Support from CDC for these efforts provides technical, epidemiological, and laboratory expertise in polio eradication and measles elimination programs, as well as in programs that address other vaccine-preventable childhood diseases; expansion of laboratory and technical capacity; development of training materials and other material support; and laboratory training and support. USAID and the United Nations Foundation have provided additional resources. National governments have exhibited a willingness to contribute actively to this effort.

The partners are in the process of defining indicators that would suggest progress and success. The level of integration of the current polio efforts are actively being measured. In addition, the number of outbreak investigations and the effectiveness of those responses are actively being monitored in a number of countries, and laboratory confirmation of suspected outbreaks is being obtained at the national level. The quality and frequency of feedback instruments are also being assessed. Clearly, improvements in communications technologies will aid these efforts. The key elements needed to design the ideal system and to develop the strategies for making the transition from existing systems to strengthened laboratory resources have been identified. Finally, the resources to begin this effort are available, but they are certainly not sufficient to sustain an effective system.



, M.D., Dr. P.H.


Colonel and Director, Division of Preventive Medicine Walter Reed Army Institute of Research, United States Army

A landmark 1992 Institute of Medicine report on emerging infections (IOM, 1992) resulted in the development of a CDC strategic plan for the nation, which suggested a specific role for the U. S. Department of Defense (DOD). Then, in 1996, President Bill Clinton issued a directive expanding the role of many federal agencies in global surveillance for infectious diseases, including DOD.

DOD’s Expanded Role

DOD’s role was expanded to include support of global surveillance, training, research, and response through centralized coordination. The DOD role includes improved preventive health programs for U.S. forces and their family members and enhanced involvement of military treatment facilities and laboratories in the United States and overseas. Beyond its health care infrastructure, DOD has some unique assets that it can bring to bear on the global problem of emerging infections.

A major asset is the DOD network of overseas laboratories in Egypt, Kenya, Thailand, Indonesia, and Peru. These are medical research and development laboratories that in some cases were established more than 50 years ago and that exist primarily for the purpose of product development. For example, the key studies conducted for the licensure of the hepatitis A and the Japanese encephalitis vaccines were done at these laboratories.

These laboratories have, in some instances, a biosafety level 3 capability. The laboratory in Cairo, Egypt, can if necessary, adapt to a biosafety level 4 capability. Although located in 5 countries, these laboratories have active research programs in about 31 countries; they have established extensive networks in their regions and have formal relationships with many ministries of health and the WHO.

The laboratories have tremendous depth. In almost every case they have expertise in virology, bacteriology, parasitology, other aspects of microbiology, veterinary medicine, and epidemiology. Although their primary purpose was to support product development, increasingly they are becoming involved with surveillance. In all, about 700 people work at these laboratories and are backed up by more than 800 more DOD scientists working on issues related to emerging infections.

The laboratories have additional assets: they are networked with state-of-the-art communications technologies and possess cutting-edge field diagnostic reagents that are field oriented, rapid, and invaluable in the response to emerging infectious diseases. In addition, the laboratories have access to special drugs and vaccines that might be of critical importance in regions with outbreaks of unusual pathogens.

Globally deployed military forces who are under medical surveillance are another unique asset. On any given day, U.S. troops are in the field in more than 70 countries. Because they are under intense medical surveillance, they provide a key opportunity to document the emergence of new conditions. The DOD serum repository is a valuable source of sera from subjects before and after disease development. These sera can be used to document exposures to various infectious agents. Currently, DOD has more than 25 million catalogued specimens from DOD personnel.

A major focus at DOD overseas laboratories is drag-resistant malaria. This is because DOD operates the largest malaria drug development program in the world and needs up-to-date information on resistance patterns. DOD also has a surveillance program for antibiotic-resistant enteric agents and for hemorrhagic fevers, including dengue, and influenza. In addition, DOD supports regional syndromic sentinel surveillance networks.

Currently, DOD is trying to support WHO’s efforts to link military public health laboratories together to conduct surveillance on antibiotic resistance or other types of medical surveillance. Military hospitals often serve as a good source of surveillance data in less developed countries because of the quality of their facilities.

DOD Involvement in Rift Valley Fever Outbreak

An example of recent DOD involvement in Africa was the outbreak of Rift Valley fever in 1997–1998 in East Africa. Approximately 80,000 people ultimately contracted Rift Valley fever, resulting in hundreds of deaths. In addition to the direct toll on the human population, there was a tremendous toll on the animal population in this pastoral economy. Using its laboratory in Kenya, DOD was able to quickly assist with the initial epidemiological and entomological investigations. At the time that the outbreak surfaced Kenya had no laboratory capacity for the diagnosis of Rift Valley fever. Specimens had to be sent to either South Africa or CDC to make the diagnosis. Using resources at its laboratory in Cairo, DOD was able to quickly transfer technology for rapid diagnosis to Kenya so that the outbreak could be defined rapidly and locally. Experts in remote sensing also collected data to establish indicators that are evident at least 3 or 4 months before outbreaks. In the future this will enable the government to initiate immunizations for animals and thus prevent the amplification of the virus and its transmission to humans. DOD also provided access to the Rift Valley fever vaccine for at-risk laboratory workers in Kenya.

Syndromic Surveillance in Indonesia

DOD is also establishing a syndromic surveillance system, called the Early Warning Outbreak Recognition System (EWORS), in Indonesia. Several sites around the Indonesian archipelago once every 24 hours report syndromic data to a central point in Jakarta, where a DOD laboratory is collocated with the Indonesian Ministry of Health. The system is focused on hospitals located around Indonesia, where nurses collect syndromic data from patients. These data are entered into a database where one can enter not only the signs and symptoms but also the specific working diagnosis. In almost real time the frequencies of various syndromes can be tracked across the archipelago.

Integrating Surveillance in the Caribbean

A different approach to infectious disease surveillance is under way in the Caribbean, in collaboration with PAHO’s Caribbean Epidemiology Center (CAREC). In 1997, CAREC brought together the national epidemiologists and laboratory directors from its 21 member countries and said that by the year 2000 they wanted to have in place a surveillance system capable of monitoring trends and impacts of emerging infectious diseases and providing timely, relevant, and accurate feedback. The concept was one of hierarchical, laboratory-based surveillance, with CAREC the regional pinnacle of the hierarchy.

DOD donated equipment for a website to CAREC so that it can receive data from its member countries and report back to them. DOD then sponsored a meeting of the 21 countries for a week of training in the use of automated equipment and other aspects of informatics for public health reporting. Each independent country took home two computers. Subsequently, DOD is providing additional equipment to each independent country and an additional week of training to further support the surveillance system. The reporting system is based on CDC’s Public Health Laboratory Information System (PHLIS). The PHLIS program is capable of integrating into one system reports from multiple types of reporting.

Facilitating Training and Capacity Building

DOD laboratories also serve as training sites, offering a number of courses in outbreak investigation, for example, throughout Southeast Asia. The aim is to transfer epidemiological and microbiological skills and to facilitate timely recognition of outbreaks and control. These courses should also bring some uniformity to the outbreak investigation process.

In countries with weaker ministries of health, such as some African nations, DOD has increasingly turned to nongovernmental organizations and commercial organizations, such as the African Medical and Research Foundation and the African Conservation Company, to establish partnerships.



, M.D.


Department of Communicable Disease Surveillance and Response World Health Organization, Geneva

There is a dire need for global surveillance of emerging infectious diseases, including in the African region. Strengthening of national surveillance systems is an important part of improving global surveillance. From this perspective the World Health Organization (WHO) assists countries with the development of national surveillance plans and surveillance standards on the basis of selected priority diseases and by use of an integrated or multidisease approach. WHO also supports epidemiology training in the field to ensure a better capacity for preparedness and response to epidemics at the national and regional levels. In addition, WHO continues to strengthen global laboratory surveillance networks, including the antimicrobial resistance network and the hemorrhagic fever surveillance network. Military networks and the Pasteur Institutes network are examples of non-disease-specific global networks, also important partners of WHO. The revision of the International Health Regulations is another important element of the WHO strategy in global surveillance and control of emerging infections.

On the response side, WHO supports a rapid epidemic response team and other global response networks such as the International Coordinating Group, which ensures that vaccines and other resources are delivered in an equitable manner during meningococcal meningitis epidemics, and the WHO Cholera Task Force, which focuses on cholera and other epidemic diarrheal diseases.

Global Epidemic Intelligence

In the area of epidemiological surveillance of emerging infections, there have been a number of new approaches, such as integrated (or multidisease) surveillance, syndromic reporting, and the development of Internet-based disease surveillance.

Global Epidemic Intelligence, established at WHO in 1996, was created to improve international preparedness and the international response to epidemics by sharing the same information in a timely fashion. It also plays an essential role in countering confusing information that can have a major impact on international travel and trade. Through active collection of information on ongoing or rumored outbreaks worldwide and rapid verification of theses reports, WHO is able to provide valuable and timely information to the international public health community.

This system requires multiple skills, not only in epidemiology, infectious diseases, and laboratory surveillance but also skills in international public health and field experience, telecommunications and informatics, and information management. It also requires partnership with the public and private sectors. Six regional offices of WHO, such as the African Regional Office (AFRO), play an essential role in this network, particularly for verification purposes, as they have privileged access to countries.

Use of the Internet

The Internet is an increasing source of outbreak-related information. For example, information can be obtained through news on media wires, electronic discussion groups, and various websites. Epidemic intelligence must take in to account the unrestricted use of the new technologies, such as the Internet and the increased participation in the health fields by nongovernmental organizations and private-sector interests, whose activities and information often bypass official reporting systems. This is a new situation and can allow additional time for proper action to be taken in advance to avert panic and minimize potential damage to trade.

To explore the extent to which nontraditional means of reporting, particularly over the Internet, can be channeled to good use, WHO developed with the Canadian Ministry of Health a computer application (Global Public Health Intelligence Network) that scans hundreds of websites and media wires 10 times a day for information that could be associated with reports of communicable diseases or disasters. Of the 450 reports of outbreaks verified in the past 2.5 years, more than 50 percent have come from the media.

Disease Distribution and Verification

The reports gathered from websites are verified and entered into a database that also contains data from other reporting sources. The information is then mapped, sometimes down to the village level (WHO/United Nations Children’s Fund HealthMap Programme).

Retrospective analysis of the data shows that diarrheal diseases—in particular, cholera—are the most frequently reported events. For the last 3 years cholera has been the most frequently reported event in the African region. Meningococcal meningitis, acute hemorrhagic fever syndromes, acute neurological syndromes, acute respiratory syndromes, yellow fever, and plague are also frequently reported. About 60 percent of all the reports processed by the WHO outbreak verification group come from the so-called emergency countries, that is, countries experiencing civil strife, civil war, and economic collapse.

The first step in the verification process is to share the report with the ministry of health of the relevant country so that it may investigate and initiate a possible response. Nongovernmental organizations and the United Nations network are important partners in outbreak verification. When an event is sufficiently verified and if it is likely to have international implications (likely spread to other countries, impact on international travel and trade, or requests for international assistance), it is shared through the weekly Outbreak Verification List (OVL) with WHO partners in international public health. The OVL reports the presented syndrome or disease, the location of the event, its source, the available figures and number of reported cases and deaths, and the contact details for WHO professionals who are monitoring this particular event. When an event is fully verified and when there is a need for public information, it is described on the WHO website and other websites and its description is published in the Weekly Epidemiological Record.

Verification can be difficult because of limited infrastructure and human resources in a country, poor communications systems, a lack of laboratory capacity, and civil conflict and war situations, which are increasingly common.

Outbreak Response Role of WHO

WHO responds to epidemics at the request of its member states. After WHO receives a request, its role is to mobilize the international response and to coordinate the response when there are different partners from different regions. Coordination is necessary for field activities, logistics, information vis-à-vis the media, contact with national authorities, and the raising of emergency funds. The response can be limited by a delay in the initial request, insufficient preparedness, time pressures, bilateral agreements that could impede coordination, and concerns for security in the field. In addition, the partners, either nongovernmental organizations or major laboratories, sometimes compete over visibility and access to clinical specimens and scientific data. When an outbreak is over, WHO should then ensure that there is a national follow-up plan, particularly in the area of epidemic preparedness and surveillance. Specific guidelines on how to handle certain types of outbreaks have also been developed, including videos, particularly targeting epidemic diseases specific to Africa, such as Ebola hemorrhagic fever.

Copyright © 2001, National Academy of Sciences.
Bookshelf ID: NBK99567


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