New and Re-emerging Diseases Sweeping the Globe

Many Nations Lack Ability to Control Outbreaks.

Released exclusively from Washington, D.C.

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WHO experts on emerging diseases–David Heymann, MD, James Leduc, MD and Maria Neira, MD–will be in Washington on Monday, October 16, 1995 for interviews. Dr. Heymann led WHO’s effort to control the Ebola virus outbreak in Zaire earlier this year.


A series of new and re-emerging diseases — such as HIV, Ebola virus, tuberculosis, bubonic plague and yellow fever — is now threatening the health of the world, according to the World Health Organization (WHO).

“The recent outbreaks have shown that the potential of epidemics is now vastly increased by the speed by which they are able to spread by the unprecedented size, concentration and mobility of populations,” says Hiroshi Nakajima, M.D., Ph.D., Director General of WHO.

“The more worrisome aspect of these new diseases is their rate of increase; at least 29 new diseases have emerged during the past 20 years,” says David Heymann, M.D. Director of the WHO Division of Emerging Diseases, created in September to mobilize a global response to the problem. “It is clear that an outbreak of disease anywhere must now be perceived as a threat to all countries, and despite many warnings, we are not yet fully equipped to contain them.”

WHO says that the reasons for the new and re-emerging diseases include:

  • Changes in lifestyle, including over-crowded cities where population growth has outpaced supplies of clean water and adequate housing; dramatic increases in national and international travel, whereby an individual traveler may be infected in one country and spread the disease to others before falling ill;
  • Deterioration of traditional public health activities such as surveillance and diagnostic laboratories needed to quickly recognize emerging problems;
  • Complacency, despite numerous warnings in recent years.

Important newly emerging diseases — Ebola hemorrhagic fever, pulmonary syndrome virus, hepatitis C, Lyme disease and HIV — have infected millions of people. In addition, antibiotic resistance has emerged as a global public health problem, making effective treatment of even some of the simplest infections difficult.

“Unrecognized micro-organisms certainly exist in nature that could cause disease just as deadly as the Ebola virus and perhaps even more so,” says Dr. Heymann. “The world is not becoming a safer place. More and more people are crowding into cities, humans will continue to intrude into once remote areas and there will always be a lack of resources in the developing world.”

The six main re-emerging diseases are:

  • Tuberculosis, an increase of 27.8 percent in case notification in 1990-93 period versus 1984-86;
  • Diphtheria, with some 54,516 cases reported in 1994, is up 141 percent from 1990;
  • Cholera, with some 384,403 cases reported in 1994, is up 454 percent from 1990, which cost an estimated $500 million in Peru alone;
  • Dengue fever, now reported in many Latin American and Caribbean countries for the first time in 50 years;
  • Yellow fever, now reported for the first time in decades in Latin America;
  • The bubonic plague, with more than 2,000 cases reported in 1993 and 1994, highest total since data first collected globally in 1954, costing some $1.5 billion in economic losses in India.

The new WHO Division on Emerging Diseases is also dealing with a third problem of diseases that show growing resistance to antibiotics, which include gonorrhea, staphylococcal infections, dysentery, tuberculosis and malaria.

“During the last 20 years, the world has been given a series of warnings abut new and re-emerging diseases, but we haven’t been listening,” says Dr. Heymann, who led the WHO response to the Ebola outbreak in Zaire earlier this year. “For example, Ebola killed more than 300 people in a remote area of Zaire. Had the outbreak occurred in a crowded capital, the death toll could have been much higher.”

WHO emphasizes that industrialized nations are often in as much danger as developing ones, a clear change from most of the post-World War II era, when communicable diseases were rapidly decreasing and antibiotics effective.

The HIV pandemic is the prime example, infecting more than 1 million Americans, and 18 million people world-wide; an outbreak of waterborne cryptosporidiosis in the United States caused 400,000 cases in April, 1993; a month later an outbreak of hantavirus pulmonary syndrome occurred in the southwestern United States; and a total of 13,109 cases of Lyme disease, which accounts for more than 90 percent of all reports on vector-borne infectious diseases in the United States, was reported by 44 states in 1993, compared with 497 cases by 11 states in 1982, which indicates its rapid emergence over the past decade. Australia experienced an outbreak of morbillivirus pneumonia in humans and horses.

“Plus, an outbreak of Ebola near an airport could mean the disease is exported half way across the world in a matter of hours,” says Dr. Heymann.

WHO Director General Nakajima set up the new Division under Dr. Heymann because of his conviction that international solidarity is needed. It will allow WHO to mobilize rapid reaction teams to tackle epidemics within 24 hours of receiving information about them. WHO is strengthening early warning systems of better surveillance and laboratories in many industrialized and developing countries, especially those that are most at risk.

In order to counter these multiple threats, WHO has adopted four major goals based on a consensus of international experts:

  • To strengthen global surveillance of infectious diseases;
  • To rebuild the international infrastructure, including regional and national centers of scientific expertise, necessary to recognize, report and respond to emerging and resurgent infectious diseases;
  • To foster applied research;
  • To enhance the international capacity for infectious disease prevention and control.

WHO Assistance in Recent Outbreaks

Plague in India, 1994 — No cases of the plague had been reported in India since 1967 until its sudden emergence in 1994 in Maharastra and Gujarat states. It caused at least 54 deaths and nearly 5,000 clinically suspected cases. The outbreak caused an estimated $1.5 billion in economic losses and triggered the exodus of 500,000 people from the city of Surat.

Diphtheria Epidemic, 1990-95, Eastern Europe and the former Soviet Union — The epidemic broke out in 1990 in the former Soviet Union, and by mid-1995, some 25,000 cases had occurred. Other cases were identified in Germany, Finland and Poland.

The epidemic has still not been brought under control because of factors such as: large migrations of peoples; the large numbers of refugees from war areas; and shortages of vaccine and antibiotics.

Ebola Hemorrhagic Fever, Zaire, 1995 — The outbreak was identified in April and declared under control in August. The virus brought on bloody diarrhea and high fever, killing more than 70 percent of the afflicted. In all, the Ebola outbreak killed some 245 people, 26 percent of them health care workers, and caused severe economic damage in affected districts.

Ebola also exposed many of the health care weaknesses in sub-Saharan Africa, including a delayed diagnosis of the disease; poor sanitation and hygiene in hospitals and health centers; and social customs, especially ritual cleansing before burial.

Yellow Fever, Kenya, 1992-93 — The outbreak occurred in the Rift Valley province, where early diagnosis was difficult because of the wild isolated terrain, and because yellow fever had never been known before in Kenya. It was first mis-diagnosed as malaria. Only a total of 63 cases were identified, and the epidemic came to a rapid end after vaccination campaigns were begun. Because the virus is now present in mosquitoes, it continues to pose a threat.

Drug Resistance

Drug resistance has emerged in the United States and other industrialized nations, as well as developing countries, as a major health problem in both local communities and in hospitals, child care centers and nursing homes.

Antibiotics that once seemed invincible are losing their effectiveness for a wide range of diseases that include tuberculosis, pneumococcal pneumonia, meningitis and gonorrhea, acquired mainly outside institutions, along with enterococcala and staphylococcal infections, acquired mainly in hospital settings.

Additionally, resistance to antiviral and antifungal drugs is emerging; also, in nearly all areas of the world where malaria occurs, drug resistance to the disease is found.

The increase in drug resistance has resulted in higher deaths and forced the use of much more expensive drugs or drug combinations, even for the more common infections, which has meant higher health care costs for both families and communities.

Yearly expenditures from anti-microbial resistance in the Unites States alone are estimated to approach nearly $4 billion and are increasing.

No U.S. national system to detect drug-resistant infectious diseases exists. Laboratory-based surveillance for drug-resistant tuberculosis, which was discontinued in 1984, is just now being re-established.

Bacterial pathogens develop resistance to antimicrobials after wide usage, and there is a need to have a reliable method of monitoring the problem. To do this, WHO has developed WHONET, which is designed for use in microbiological laboratories to facilitate the local management of antibiotic sensitivity test results from routine clinical isolates. At present, more than 200 hospitals and laboratories utilize WHONET.

WHO is also working with pharmaceutical manufacturers and researchers to persuade them to continue their work in the development of new antibiotics to replace those that are no longer effective.

Regional Problems

Africa — This continent is experiencing an increasing frequency of epidemics on a much larger scale. Cholera is now common in 36 African countries. Meningitis and bubonic plague is prevalent in many countries and bloody diarrhea is increasingly common. “New” diseases such as Ebola virus and lassa fever — a hemorrhagic fever with signs and outcome similar to Ebola — are now appearing.

“The role of WHO and its collaborating partners is essential in assisting countries to control epidemics when they happen, but it must also help countries strengthen their ability to detect disease by supporting training in epidemiology and disease surveillance at local levels, and public health laboratory surveillance nation-wide,” says Dr. Heymann.

Asia — During the last decade, overcrowding, increasing urbanization, military conflict, natural disasters such as floods and the overwhelming problem of poverty have all exacerbated the problems of communicable disease, especially in southeast Asia.

The region has high levels of polio, leprosy and neo-natal tetanus. In 1992, a new strain of cholera emerged in India, along with the plague in 1994. High mortality rates are produced by acute respiratory infection, tuberculosis and diarrheal diseases. Dengue hemorrhagic fever, Japanese encephalitis, meningococcal meningitis and HIV/AIDS are all increasing in southeast Asia.

WHO’s aim in the region is to control communicable disease through development of better epidemiological and laboratory skills among national health care workers. WHO is concentrating its effort in the key area of strengthening existing systems of surveillance.

Latin America and the Caribbean — In 1991, cholera returned to the Western Hemisphere for the first time in the 20th Century, and the disease reached epidemic proportions, especially in Peru, where it affected at least one million people and caused $500 million in financial losses. The epidemic is still increasing in certain areas of Central America, Brazil and Peru.

Reported cases of dengue fever are rapidly increasing, even in areas bordering the southern United States. Yellow fever, affecting poor rural farmers in Peru particularly, plague, hemorrhagic fevers, hanta virus diseases, HIV/AIDS and malaria are all increasing threats in the region.

Poverty and inequity causing major health differentials between population groups make epidemic control especially difficult.

The Pan-American Health Organization (PAHO), WHO’s affiliate organization in the Western Hemisphere, is collaborating with country level health institutions to coordinate efforts to identify and control these diseases.

The WHO offices, including PAHO, are developing a regional plan of action to combat emerging and re-emerging infectious diseases and are setting these goals to reinforce goals set by the new Division: to strengthen regional and national laboratory and surveillance networks; to establish national and regional infrastructures for early warning and rapid response to infectious diseases; to promote the development of applied research in rapid diagnosis, epidemiology and prevention; and to strengthen regional capacity for effective implementation of prevention and control strategies.

Category: Press Release