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DENGUE, CHIKUNGUNYA, AND OTHER VECTOR-BORNE DISEASES (VBDs): SURVEILLANCE AND RESPONSE IN LATIN AMERICA AND THE CARIBBEAN: THE ROLE OF THE PAN AMERICAN HEALTH ORGANIZATION
To better understand the role of the Pan American Health Organization (PAHO) in support of the prevention, control, and elimination of vector-borne diseases in the American continents, it is useful to briefly describe what PAHO is, what has been done, and where the organization is today in its practice.
The Pan American Health Organization
During the 19th century, four international sanitary conferences that included participation of countries from the Americas were held in Europe with unclear
1 Pan American Health Organization.
results. Later in the 1870s, an epidemic of yellow fever spread in several countries of South America, and from there it reached the United States of America through maritime contacts, resulting in a major epidemic with more than 20,000 cases and deaths.
The countries of the Americas resolved to take action with an international perspective; thus a 5th International Conference was arranged to be held in the Americas for the “purpose of securing an international system of notification as to the actual sanitary situation of ports and places.” Around the same time, inter-American cooperation was beginning to grow, and during the 1890s a first international conference was also organized to establish the International Union of American Republics (today known as the Organization of American States).
In 1901, during the 2nd Conference of the International Union (in Mexico) a recommendation was made to call a general convention of representatives of health from the different American republics, with the purpose of proposing sanitary agreements and regulations. The First General International Sanitary Convention of the American Republics, to assure effective cooperation in promoting health in the Americas, was held in Washington, DC, in December 1902. This meeting gave birth to the Pan American Sanitary Bureau.
Originally called the Pan American Sanitary Bureau (PASB), PAHO today is the world’s oldest international public health agency continuously working.
PAHO can be considered a coalition encompassing 30 percent of Earth’s land mass and 14 percent of the world’s current population. With 28 country offices in 35 countries, PAHO’s scope has also continued to grow. The initial focus on controlling epidemic diseases has broadened to noncommunicable diseases, better health education, health systems and services, essential medications, mental health, and other fields that include environmental improvements designed to help all populations, especially communities in need.
PAHO’s current vision is to serve as the major catalyst for ensuring that all the peoples of the Americas enjoy optimal health, and contribute to the well-being of their families and communities. PAHO’s current mission is to lead strategic collaborative efforts among member states and other partners to promote equity in health, to combat disease, and to improve the quality of, and lengthen, the lives of the peoples of the Americas.
The Fight Against Vector-Borne Diseases in Latin America and the Caribbean
PAHO was the first international health organization to organize a united front against the spread of yellow fever in what today is a key shipping route connecting the Atlantic and Pacific Oceans. Founded by 11 countries, PAHO’s first task was to eliminate yellow fever and malaria in the Panama Canal Zone.
The 2nd International Sanitary Convention, which took place in 1905 in Washington, DC, continued to emphasize the importance of yellow fever, noting the success of control campaigns in Cuba, the Panama Canal Zone, and Mexico. Setting an important precedent, the convention resolved that, in event of epidemics, national health authorities would be responsible for quarantine and disease control campaigns.
Despite successful achievements, yellow fever has continued to be a public health concern in the Americas, and it is a reportable disease according to the International Health Regulations coordinated by the World Health Organization (WHO). Currently, between 16 and 60 cases are reported every year, despite the millions of vaccines applied yearly to prevent its spread, mostly in South America where a dozen countries remain as endemic territories or are under permanent threat.
PAHO’s role is to support countries to keep up-to-date capacity in prevention, control, diagnosis, adverse event management, and risk communication. In addition, PAHO periodically collaborates with WHO in the reviewing of guidelines and recommendations for endemic or at-risk countries.
The efforts to eradicate malaria worldwide were spurred on by the successes seen through use of DDT to kill anopheline vectors of the disease. The global launch to eradicate malaria was held in Mexico City in 1955. After World War II, WHO helped countries put together programs of DDT spraying to combat malaria transmission. PAHO coordinated these efforts in the Americas. These campaigns partially interrupted malaria transmission, and it was reflected in dramatic reductions in infection and number of cases in a relatively short time between the 1960s and 1980s.
With more than one million cases in the year 2000 to less than 430,000 malaria cases in 2013, the Americas have earned a first place in steadily decreasing the incidence and mortality (82 deaths in 2013) due to malaria in the last decade.
One of PAHO’s roles has been concentrated in maintaining political and financial interest from governments and international stakeholders in supporting their national malaria programs and efforts towards control and elimination. For this, permanent consultation with countries has allowed PAHO to properly analyze and map the technical needs and keen efforts necessary to advance the agenda of malaria elimination in the region.
Resolution CD51.R09, approved by PAHO’s member states in 2011, described the strategy and plan of action elaborated to aggressively pursue control and advance towards the elimination of malaria in the Americas. In the year 2015, a new regional strategy and plan of action will be presented considering the advances reached by the countries, including the potential use of newly developed and available tools and in concordance with recommendations of the forthcoming
new WHO Global Malaria Strategy 2016–2030. Among the main areas of action, PAHO supports countries in the following ways:
- Intensify efforts directed toward malaria prevention, surveillance, early detection, and outbreak containment in various program contexts (including malaria elimination)
- Integrated vector management by promoting, strengthening, and optimizing mechanisms and tools for judicious and cost-effective vector management
- Malaria diagnosis and treatment by strengthening efforts to achieve universal access to prompt, accurate, and quality malaria diagnosis, followed by rapid treatment with effective antimalarial medicines
- Advocacy, communications, partnerships, and collaborations through specific actions that foster an environment that promotes sustainability and supports collaborative efforts and best practices to combat the disease
- Health systems strengthening, strategic planning, operational research, and country-level capacity building
- Optimize efforts to strengthen health systems (including strategic planning, monitoring and evaluation, operations research) and the countries’ capacities to address their respective malaria challenges both relevantly and adequately
Similar to malaria, PAHO also has played a role in the history of (attempted) Aedes aegypti eradication or control as described in the PAHO Director’s Report from 1958, but outcomes so far are different. In the Americas, dengue incidence has increased 30 fold in the last 50 years, and between 2008 and 2012 more than 1.2 million cases of dengue were notified annually, including 28,233 severe cases and 1,000 deaths. Furthermore, 2013 had the highest burden of disease ever registered, with the largest epidemic in the history of the Americas, with a total of 2.3 million cases, 37,898 severe cases, and 1,318 deaths.2 This disease has a high social and economic impact, affecting not just the patient, but also families and the community as a whole. The estimated economic cost of the disease in the region supersedes US$2.1 billion per year.
Dengue and its main vector in the Americas have continued to spread geographically, and its unusual capacity to survive in cold climates and temperatures has increased. The United States is not exempt from this threat, as documented in 2013 by Añez and collaborators from the U.S. Food and Drug Administration. The geographic spread of these potentially harmful vectors has already invaded a
significant portion of North American soil. Currently all four serotypes of dengue virus (I, II, III, and IV) are known to be circulating in the Americas, and simultaneous circulation of all four types are documented in at least eight countries.
PAHO/WHO, through the Dengue Regional Program, supports member states in the implementation of the Integrated Management Strategy for the Prevention and Control of Dengue (IMS-Dengue). This strategy was adopted by the countries of the Americas through the Resolution of PAHO’s governing bodies CD44.R9 in 2003; since then, 22 countries of the Americas have developed national IMS-Dengue prevention and control plans. In addition, 20 of the countries have completed an assessment of their IMS-Dengue strategy, with the support of experts from the International Technical Group on Dengue (ITG-Dengue), following the recommendations of Resolution CSP27.R15, adopted in 2007 by the 27th Pan American Health Organization Sanitary Conference.
The current efforts of the Regional Dengue Program include the following:
- Strengthen epidemiological surveillance of dengue through the development of a generic model of an integrated epidemiological surveillance system.
- Strengthen laboratory networks in the management of effective practices in the diagnosis of dengue through the Dengue Laboratory Network of the Americas (RELDA, acronym is from the Spanish name of the network).
- Strengthen vector monitoring and control in entomology, integrated vector management, and monitoring of insecticide resistance.
- Improve clinical management of patients through the adaptation for the Americas of the WHO clinical guidelines published in 2009, a second edition of which is currently in progress.
- Strengthen social communication by use of communication planning methodologies to improve behaviors of populations facing the dengue problem, including political leaders, health officials, residents, and other stakeholders.
As the Americas evolve along with the rest of the world, communication and international trade facilitates the travel or transport of individuals and goods, and with them, the spread of diseases and their vectors. On December 2013, PAHO/WHO received confirmation of the first cases of autochthonous transmission of chikungunya virus (CHIKV) in the Americas. Yet, since 2012, PAHO/WHO and the U.S. Centers for Disease Control and Prevention (CDC) collaborated together and with countries in the region, anticipating and preparing for the risk of introduction of the virus. As a result of these efforts, new joint guidelines were published that same year for preparedness and response on CHIKV introduction. These guidelines were aimed to help countries throughout the Americas improve
their ability to detect the virus and be prepared to monitor, prevent, and control the disease.
Ever since the first cases were reported, PAHO has officially acknowledged the reporting of over 900,000 cases (over 15,000 laboratory diagnosed), and close to 150 deaths related to CHIKV in more than 30 countries and territories of the Americas.
In addition to the already developed capacity in countries to properly respond to any chikungunya-related threat in the Americas, PAHO has from the very beginning supported countries to (a) formulate evidence-based outbreak management plans and effectively manage cases and outbreaks, and (b) improve their reporting systems and technical skills to properly diagnose cases, and improve their capacity to assess and implement vector control activities. PAHO also publishes guidelines and handbooks for surveillance, case management, laboratory detection, and vector control for its member states and receives support from a network of referral laboratories located in Argentina, Brazil, Cuba, French Guyana, and the United States.
Countries in the Americas have a history of success in achieving public health goals, and elimination of diseases has been in the agenda for more than 50 years. Ever since the eradication of smallpox, initiated in the Americas in the 1950s, the region grew its reputation for tackling vaccine-preventable diseases and showing the world that it was possible to eliminate them. After smallpox, polio, measles and rubella have followed the same path, as the Americas proudly reflects their achievements in the health of all children and adults. Nowadays, the Americas are convinced that elimination of diseases can be expanded to conquer diseases that cannot be prevented with immunizations; and as examples of such possibilities, in 2013 Colombia became the first country in the world to be verified by WHO as having eliminated onchocerciasis transmission, followed recently by Ecuador in September 2014.
Understanding the role of the Pan American Health Organization in the public health history of the Americas, we note the following:
- The Pan American Health Organization (PAHO) is the world’s oldest international public health agency continuously working for the public health and well-being of the Americas.
- Vector-borne diseases have been a historical public health challenge to the Americas, and they continue to be a significant threat.