Pan American Health Organization

Emergent diseases and critical health problems undermining development


The Region of the Americas has made substantial progress over the past decade in achieving health-specific goals related to maternal and child mortality, reproductive health, infectious diseases, and undernutrition. Socioeconomic development, environmental factors, the relative strength and resilience of health systems, and improved access to health services have been instrumental in these achievements (). However, advances at the national level continue to obscure disparities among certain subpopulations. The slow progress in closing gaps resulting from avoidable inequalities continues to negatively affect the balanced distribution of those advances (). For example, scaling up evidence-based interventions to fight communicable diseases (CDs) and improving maternal and child health is necessary but not sufficient to resolve health disparities across different populations. Progress, while ongoing, has been nonlinear, and potential social, economic, environmental, and public health crises threaten to reverse the fragile gains.

The Region also faces new challenges from emerging and reemerging infectious diseases that adversely affect communities, families, economies, and health systems and services. Lessons learned from past emergencies (i.e., the 2009 influenza pandemic) have resulted in greater preparedness and increased awareness of the need to strengthen surveillance (). Yet, in other cases, such as the dengue, Zika, and chikungunya epidemics, important challenges remain that will require a coordinated, multisectoral, integrated response.

Achieving the goals of the 2030 Sustainable Development Agenda requires more integrated and collaborative approaches to address inequities in the Region across the social, environmental, and economic dimensions of development, including a clear intergenerational vision. Health systems must adopt a more decisive role in efforts to increase equity and sustainable development, ensuring effective coverage and quality of health services and interventions, and, most importantly, contributing to build coherence and synergy of actions across different sectors, both nationally and locally.


In recent decades, the patterns of disease in the Region of the Americas have shifted, with an overall decrease in both the communicable disease (CD) burden and maternal and child deaths linked mainly to disease control, an aging population, increased political will, and improvements in socioeconomic conditions (). Over the past two decades, in all countries in the Region, CDs and maternal, neonatal, and nutritional diseases have dropped below noncommunicable diseases (NCDs) and injuries as causes of years of healthy life lost (disability-adjusted life years). Progress in decreasing mortality over the past decade has been greatest in Latin America and the Caribbean (LAC), with reductions of more than 30% in the Dominican Republic, Guatemala, Haiti, Honduras, Mexico, and Nicaragua (). However, significant disease burdens persist in some countries, such as Bolivia, Haiti, Guatemala, Guyana, and Peru, where more than 20% of deaths are estimated to be related to CDs and maternal, neonatal, and nutritional diseases ().

Sustained long-term economic development with improvements in public sanitation, housing, nutrition, and health care over the past decade has driven a transition in health outcomes (). Despite this progress, the persistence of specific CDs as well as preventable maternal and child illnesses hinders the well-being, social cohesion, and development of some populations in the Region. These conditions are markers of inequities related to gaps in socioeconomic development.

The Millennium Development Goals (MDGs) for 2000–2015 helped mobilize political will and address health development and equity challenges, and the Sustainable Development Goals (SDGs) (2016–2030) are building on that momentum (). This section covers health-related goals of the MDG agenda—maternal and child mortality, reproductive health, infectious diseases, and undernutrition—focusing on current challenges in public health policy and action, including control and/or elimination of CDs within the context of changing health outcomes, persisting inequities, and a re-strategized approach to sustaining gains while leaving no one behind.

Control of Transmissible Diseases

Diseases are not limited by geopolitical boundaries and thus can spread quickly across borders through international travel and trade, with a single health crisis in one country potentially affecting the economies and livelihoods of the entire international community. In the Americas, there are a wide variety of settings and unique scenarios that may contribute to the emergence of infectious hazards events such as populated urban centers affected by multiple natural disasters, and remote rural areas lacking access to drinking water and sanitation, where close contact between humans and animals is common. Risk of CDs in the Region is also affected by environmental pressures associated with, among other events, rapid urbanization and climate change. For example, the emergence and spread of arboviruses depends on the presence and abundance of vectors, which is in turn related to various social, economic, and environmental factors (). The macrodeterminants that influence the onset of these diseases are compounded by climate change effects, which impact the intensity and duration of rainy seasons and hurricanes, give rise to intense droughts, and alter biodiversity (). Persisting poverty and social inequities also impede sustainable, equitable progress in the control of CDs.

Of all human pathogens worldwide, 61% are classified as zoonoses and account for 75% of all emerging pathogens in the past decade (). A study analyzing the importance of zoonoses and CDs common to man and animals as potential public health emergencies of international concern (PHEIC) reported that 70% of recorded PHEIC in the Region were within the animal/human health interface. Of these, 25% were food safety events (). These results underscore the importance of the animal/human health interface and intersectoral collaboration. Several zoonotic diseases, such as influenza and leptospirosis, are listed as top 10 infectious hazards in the Americas in the WHO Event Management System (EMS) (). Plague, another zoonotic disease, is one of the few diseases requiring notification under IHR 2005, even though there are no current plague outbreaks in the Region ().

Other challenges in controlling CDs in the Region are related to changes in demographics and lifestyle and issues such as availability of treatments and drug resistance. For example, multiple chronic infectious diseases have increased with aging populations. Antimicrobial, antifungal, antiparasitic, and antiviral drug resistance has emerged as a factor with high economic impact in the annual global gross domestic product (GDP), which could fall between 1.1% to 3.8% in 2050 (depending on estimated levels of antimicrobial resistance), according to a World Bank report (). Drug resistance may jeopardize efforts to eliminate malaria, tuberculosis (TB), and HIV and would thus have a direct impact on the lethality of these diseases (). Preventing the spread of resistant infections and slowing the emergence of resistance overall is critical in the Region.

Among the groups at highest risk of contracting infectious diseases are people with inadequate access to water and sanitation and those who live below the global poverty line (), particularly pregnant women, children, and immunosuppressed patients. Some populations may also face barriers in access to prevention and control services due to stigma and discrimination based on their behaviors, sexual orientation, or ethnicity that can be compounded by legal frameworks and cultural and religious beliefs.

While the circulation of many established pathogens in the Americas has decreased, both new and traditional infectious diseases, such as Zika virus (ZIKV), chikungunya virus (CHIKV), dengue virus (DENV), plague, cholera, yellow fever virus (YFV), and leptospirosis, periodically emerge or reemerge. This poses challenges to health systems that lead, in some cases, to competing political, social, and technical perspectives, the absence of an organized and efficient public health strategy.

Disease emergence or reemergence is related to social, political, and economic factors that have resulted in increased movement among the population, increased pressure on the environment, and environmental changes, as well as disparities across different social groups related to a lack of health service capacity in disease detection, prevention, and control (). Prevention and management of emerging diseases is a major health concern in the Region. Acute outbreaks of DENV, CHIKV, and ZIKV have increased the pressure on health systems, highlighting their structural weaknesses and the shortcomings of fragmented approaches to public health emergencies. In addition, the Region faces outbreaks of reemerging diseases such as yellow fever, cholera, and plague, which can cause devastating epidemics. These outbreaks pose a threat to public health security and can undermine socioeconomic progress.

Some of the more important Regional challenges in communicable disease control—foodborne diseases (FBDs), health care–associated infections (HAIs), arboviruses, influenza, plague, leptospirosis, and cholera—are described below.

Foodborne diseases (infections and intoxications)

Foodborne diseases can be defined as conditions commonly transmitted through ingested food and comprise a broad group of illnesses caused by enteric pathogens, parasites, chemical contaminants, and biotoxins. FBDs reduce societal productivity, impose substantial stress on the health care system, and reduce economic output by adversely affecting tourism, food production, and access to domestic and export markets. In the Caribbean, acute gastrointestinal illness associated with contaminated food (which has an annual incidence of 0.65–1.4 cases/person) has an estimated cost of US$ 700,000–US$ 19 million per year (). The U.S. Centers for Disease Control and Prevention (CDC) estimates that each year about 1 in 6 people in the United States gets sick, 128,000 are hospitalized, and 3,000 die of FBDs, at a total cost of US$ 77.7 billion ().

Socioeconomic determinants lead to different levels of exposure and vulnerability to FBDs (). Poverty, education, ethnicity, gender, demographic factors, living and working conditions, and trade are structural determinants of food safety and different modes of food production, handling, and consumption. For example, ethnicity is often structurally linked to inequity, leading to conditions prejudicial to food security and safety. Brucellosis due to the consumption of raw milk or raw milk products such as cheese occurs more frequently among indigenous populations (). Female literacy rates and education are also important factors in access to food and food safety ().

Health care–associated infections

Health care–associated infections (HAIs) are linked to significant morbidity and mortality and pose a major problem for hospitals and other health care delivery settings throughout the world. Estimating HAI incidence Region-wide is challenging, but some countries have national surveillance systems that include hospital-acquired infections (). In 2014, the United States reported more than 700,000 HAIs and 75,000 deaths in patients with HAIs ().

The economic impact of HAIs is substantial. The costs of treating a bloodstream infection in the United States can be high as US$ 45,000 (). Data from Latin American countries indicate that treatment of HAIs accounts for 15%–35% of operational costs for critical care units ().

Implementing infection prevention and control programs, which include surveillance and targeted strategies at the hospital level, can prevent 55%–70% of HAIs (). Although the main prevention strategies are not resource-intensive, many countries do not have HAI control programs at the national and hospital level (), and implementation of the programs in countries where they do exist remains a challenge. For example, hand-hygiene campaigns at health care facilities showed implementation rates of about 50% ().

In the Americas, the changing population demographics, increasing number of patients with comorbidities and chronic treatments, development of antimicrobial resistance, and more complex medical care aggravate the challenge posed by HAIs.


Despite vector control efforts, in recent years the prevalence of viral infections transmitted by arthropods has increased worldwide (). Emerging epidemics in the Americas from new arboviruses such as CHIKV and ZIKV and already endemic viruses such as DENV and the reemergence of YFV reflect important changes in patterns of disease (, ). A recent example was the PHEIC declared in February 2016 in response to the increasing numbers of ZIKV-associated neurological syndromes ().

The characteristics that make these epidemics complex issues for prevention and control include the following: (1) vectors’ adaptation to new habitats, use of unusual breeding sites (e.g., sewers and septic tanks), and expansion to new geographic areas or areas where they had been eliminated (e.g., the reinfestation of Aedes aegypti in continental Chile); (2) virus spread in densely populated areas in the Region; and (3) the simultaneous circulation of closely related pathogens and new clinical manifestations. All of these factors contribute to the increase in virulence and pathogenicity of arboviruses in the Americas.

The association between congenital ZIKV infection and birth defects, including microcephaly, has prompted concern among health officials and the public, highlighting the need to address the issue from both a human rights and reproductive health perspective. The report of congenital syndromes has demonstrated gaps in the proportion and number of cases reported by each country, mostly due to differences in surveillance systems. Therefore, standardized methodologies should be implemented.

The epidemiologic status of arboviruses in the Region is complex. DENV control efforts have decreased fatality rates, but incidence and morbidity are on the rise. For example, in 2015, DENV case fatality decreased by 23% compared to 2012, but incidence increased by 44% over the same period (). In December 2013, after autochthonous transmission of CHIKV in Saint Martin (French territory) was confirmed, the virus spread rapidly from that focal point to the northern coast of South and Central America. In 2015, transmission of CHIKV was documented in 44 countries and territories in the Region. Similarly, the dissemination of ZIKV has rapidly disseminated following the first detection of the virus in northeast Brazil in May 2015 (). By 2016, the virus had been confirmed in 40 countries and territories in the Region (). The new patterns of arboviral disease, including the emergence of ZIKV and its cocirculation with other arboviruses in areas where only DENV had been documented, highlight the need for more research on the pathogenesis and clinical and epidemiological behavior of these viruses in new habitats.

Emerging and reemerging epidemics are causing an overload on health systems, affecting families and communities. Challenges include difficulties in clinical and laboratory diagnosis as well as surveillance (). These epidemics also increase the pressure on social infrastructures in affected countries and territories. Chronic disease manifestations or sequels can affect the productivity of the population as well as individual and national incomes. Congenital health problems in newborns related to virus infections can result in the need for long-term care and family and community support. Although some research has been conducted (, ), the economic and social impact of arbovirus infections has not been fully estimated.

The response to arbovirus epidemics requires a multisectoral approach. Responses limited to the health sector increase the risk of higher-cost outcomes with less social impact and more inequity. The promotion of an integrated approach for arboviral disease surveillance, prevention, and control should therefore be a priority.


Influenza is estimated to cause about 80,000 deaths annually in the Americas (). In 2013–2015, there were tremendous gains in the Region related to the surveillance of influenza. There are currently more than 100 hospitals in the Americas conducting influenza surveillance according to global standards and 28 national laboratories carrying out virologic surveillance. These hospitals and laboratories, working with their ministries of health, international partners, and PAHO/WHO, developed a Regional influenza network, SARInet, which was formally established in 2014. This type of Regional collaboration allows for the sharing of experiences, lessons learned, and resources and has created a structure to respond to questions of public health importance, such as the burden of influenza-associated hospitalizations.

Groups at higher risk for adverse outcomes from influenza infection include children, the elderly, pregnant women, and persons with specific coexisting conditions. It is recommended that these groups receive the influenza vaccine and early antiviral therapy (e.g., oseltamivir) in order to decrease their risk of prolonged hospitalization and death (). Trends in the early use of antiviral therapy are difficult to monitor due to untraceable purchases of antiviral products without a prescription, but increased use of the influenza vaccine in the last 5 years has been reported. In 2014, 40 countries and territories in the Americas used the vaccine, and 12 of them (29%) targeted pregnant women in their coverage (compared to seven countries/territories in 2008). Among the 23 countries reporting coverage data, on average, 75% of adults ≥60 years, 45% of children aged 6–23 months, 32% of children aged 2–5 years, 59% of pregnant women, 78% of health care workers, and 90% of individuals with chronic conditions were vaccinated during the 2013–2014 vaccination campaigns (). Estimates based on 2013 surveillance data from LAC suggest that the vaccine was 52% effective in preventing medically attended severe influenza infection ().

There is much more to be done, especially in strengthening influenza surveillance at the human-animal interface, developing estimates of the burden of influenza-associated hospitalizations, strengthening the rapid response capacity, and gaining a better understanding of the barriers to access to vaccination among various population groups. Targeting these aspects of the work plan requires a multisectoral approach and open communication and data sharing among partners.


Plague persists in the Americas, with endemic foci in Bolivia, Brazil, Ecuador, Peru, and the United States (). Since 2009, small outbreaks and occasional human deaths have occurred, including in hospital settings. Notification of pneumonic plague is mandatory under the IHR (). Plague’s epidemiology is highly entangled with the ecology of its vectors and reservoirs, which are influenced by climatic, ecological, and social changes that have contributed to its resurgence.

The Andean region population has the highest risk of ecological and climatic changes derived from the El Niño Southern Oscillation (ENSO). The effects of ENSO have been associated with plague reemergence in the past (1992 and 1998). High-risk populations include those living in semiarid areas surrounded by a rural agricultural (intensive or extensive/traditional) landscape, where interface with the sylvatic cycle of the plague reservoir may be ubiquitous. Local housing conditions can also increase the risk of plague; isolated households in maize or sugarcane production areas, with adobe homes that have soil floors, high intrahousehold human density, and store agricultural products inadequately, are most at risk.


Estimates suggest that in the Americas, over the last decade there have been more than 100,000 cases of leptospirosis, causing 5,000 deaths annually. Consequently, leptospirosis has garnered more attention, mostly during outbreaks (). However, the disease remains under-reported due to nonspecific symptoms that mimic those of DENV, malaria, and influenza, and because it requires laboratory confirmation (). The diversity of leptospirosis’ animal carriers creates additional challenges for prevention and control.

Studies have identified environmental drivers of leptospirosis, such as heavy rains or floods, frequently related to outbreaks with a higher number of cases (). Alkaline and neutral soil types facilitate the survival and persistence of the bacteria (). Socioeconomic drivers include living in dense urban or peri-urban areas with inadequate waste collection and sanitation, lack of potable water, and poor housing conditions (). As an occupational disease, leptospirosis affects rice workers, animal handlers, sewer workers, and gold miners (). Rural workers who acquire leptospirosis in areas with limited access to health services may not be able to return to their jobs and some may even die. Severe leptospirosis cases may lead to renal failure that requires hemodialysis (). If this complex and costly procedure is not available, the chances of patient recovery are low.


Cholera is still present in the Americas. In 2010–2016, cholera was reported in Cuba, the Dominican Republic, Haiti, and Mexico. In Haiti, Vibrio cholerae O1 has persisted since 2010 and epidemiological peaks have been observed during rainy periods due to the increased water runoff feeding the endemic transmission, which is maintained through movement of the population and inadequate hygiene practices. The oral cholera vaccine was introduced in Haiti in 2015, and approximately 373,000 persons were vaccinated. However, on 4 October 2016, Hurricane Matthew struck the departments of Grand Anse and Sud, generating more cases than normally expected for the season. Water and sanitation infrastructure is limited in the country and was destroyed in the southern peninsula by the hurricane. Total sanitation coverage in Haiti remains low (28% in 2015); in 2012, in the poorest population quintile, 90% were still practicing open-air defecation (). Drinking water coverage in Haiti declined in urban settings over the period 1990–2015, despite a national increase of 2%; in 2012, in the poorest population quintile, only 1% had access to improved water sources. Water treatment centers in urban settings in Haiti need to improve their performance in water chlorination and routinely measure fecal coliforms and residual chlorine in drinking water. In rural settings, sustainable local water chlorination strategies still need to be devised. Without adequate investment in sewage discharge infrastructure, improvements in the current endemic cholera situation in Haiti will be slow. The Dominican Republic and Cuba reported cholera cases related to Haiti’s outbreaks. Differences in health service infrastructure, sanitation conditions, and access to safe water help explain patterns in cholera spread across the three countries. Mexico also suffered a cholera outbreak related to the Haitian strain between 2012 and 2014 ().

Conditions Targeted for Elimination

Disease elimination and eradication are the ultimate goals of public health. The successful eradication and/or elimination of diseases such as smallpox (1971), polio (1994), rubella (2015), and measles (2016) and significant progress in the control of many infectious diseases have prompted global and Regional target-setting, collective decision-making, and action towards elimination of goals with regard to many diseases.

Nevertheless, the costly up-front investments required to eliminate diseases and the risk of failure are cause for concern. The benefits of disease elimination include the positive return on the investment in most cases, ending important causes of disability and death, improved results in health service delivery, and closing the equity gap (). Lessons learned from previous elimination successes show that the societal and political commitment of countries is key to maintaining efforts to achieve elimination (). To support the elimination agenda, countries need to move beyond a perspective based solely on cost-effectiveness. Disease elimination requires political commitment, a human-rights- and gender-based approach, and a strategy that addresses structural and social determinants, focusing on the most excluded and vulnerable populations.


With regard to HIV, 2016 was a turning point. The Americas, which has an estimated 3.4 million people living with HIV, is moving toward ending the AIDS epidemic by 2030, as marked by the 2016 United Nations General Assembly (UNGA) High-Level Meeting on Ending AIDS, held in New York, where heads of state from member countries endorsed the Joint United Nations Programme on HIV/AIDS (UNAIDS) Fast-Track strategy to end the AIDS epidemic by 2030 (). This is an important challenge given that an estimated 25% of people with HIV in LAC do not know their serostatus and a 55% were receiving antiretroviral treatment (ART) in 2015 ().

LAC countries have the highest level of ART coverage of all low- and middle-income countries (LMICs) and have achieved a remarkable reduction in new infections in children (a 55% decrease since 2010). However, challenges remain in curtailing new infections, and an effective response is complex given the nature of the epidemic. In 2015, LAC experienced a decreasing trend in HIV deaths and new infections compared to 2005 (a 32% versus 10% decrease respectively). However, the rate of reduction in new infections slowed after 2010, and has begun to increase in the past 2 years. The burden of HIV is not equally distributed and key populations in the Americas, such as gay men and other men who have sex with men (MSM), transgender women, and sex workers, are disproportionately affected compared to the general population. Key populations also include prison inmates, certain ethnic groups (e.g., the Honduran Garifuna population and Canadian Aboriginal people), the homeless, non-injecting drug users, and young women in the Caribbean. These high-risk groups are increasingly vulnerable and often driven underground due to various factors including stigma and discrimination in their communities and at health service facilities (). Stigma and discrimination can lead to delayed care-seeking. In 2015, almost one-third of newly diagnosed HIV cases accessed care with a highly compromised immune system ().

The HIV epidemic uncovers social inequities, stigma and discrimination and poses challenges to health systems. Stigmatization of same-sex relationships and sex work hinders access to HIV prevention services and leads to an increase in risky behaviors (). Homophobia drives MSM away from HIV testing and prevention activities and is associated with lower adherence to treatment. Women in key populations face stigma and discrimination in various forms, including violence and violations of their human rights ().

Ending AIDS by 2030, to meet the goals of the Sustainable Development Agenda, will require increased financial investment to expand services and improve the prevention response. UNAIDS has estimated that US$ 3.05 billion was allocated to finance the response to HIV in 2014 in LMICs in the Region, with 87% of that amount coming from domestic (in-country) resources. The Americas region is a global leader in terms of supporting the HIV response with domestic funds, although one-third of countries depend on external donors for much (more than 40%) of their response (particularly Haiti, Bolivia, and the Dominican Republic). Other requirements for meeting Agenda goals include (1) the decentralization of services, to support the expansion of HIV testing and treatment for all; (2) the implementation of models for delivery of prevention services, with a focus on the most vulnerable populations, and those at highest risk; and (3) the elimination of stigma and discrimination, including the elimination of punitive laws and policies that create barriers to the receipt of health care and the protection of human rights.

Box 1. Elimination of mother-to-child transmission (MTCT) of HIV and congenital syphilis (CS) in LAC

In 2015, Cuba became the first country credited by WHO for eliminating MTCT of HIV and syphilis. Other countries and territories, such as the United Kingdom Overseas Territories (OKOTs) and Eastern Caribbean countries, have applied to WHO for accreditation for HIV elimination. As of 2015, 19 countries and territories in the Region had reached CS rates compatible with the elimination of MTCT of syphilis ().

Data suggest that testing for HIV and syphilis has been integrated into antenatal care (ANC) services, and the goals of eliminating MTCT of HIV and syphilis are seen as indicators of good quality in maternal and child health services. Despite the high rates of testing and treatment coverage (in 2014, 75% and 79% for HIV and syphilis testing, respectively, and 81% and 85% for treatment of pregnant women for HIV and syphilis, respectively), the neediest and most vulnerable populations are underserved ().

Health service barriers for the elimination of CS in LAC countries include late access to ANC; the need to attend health centers multiple times (for diagnosis and treatment of syphilis), often resulting in a lack of follow-up care for syphilis-positive pregnant women; penicillin shortages and stock-outs; uncommitted budgets; and lack of partner treatment, resulting in syphilis reinfection in pregnant women (). To eliminate CS, it is necessary to address sexual health and syphilis prevention as well as diagnosis and treatment among women of reproductive age and the general population. Therefore, effective responses must address HIV and sexually transmitted infection (STI) prevention in the community, satisfy the need for family planning, and rapidly identify and treat early infections, including in sexual partners ().

Sexually transmitted infections

STIs have often been neglected in favor of the HIV response, but the socioeconomic costs of these infections and their complications are substantial. For example, they rank among the top 10 reasons for health care visits in most developing countries (). Annually, 64 million new cases of four curable STIs (Chlamydia trachomatis, Neisseria gonorrhoeae, syphilis, and Trichomonas vaginalis) are reported among people 15–49 years old in the Americas (2012 data) (). High levels of STIs among key populations such as gay men and other MSM, sex workers, transgender populations, and specific indigenous and ethnic groups in LAC have been reported (). Reported data for 2008 and 2012 show a small decrease or stagnation in the incidence and prevalence of the four curable STIs among men and women 15–49 years old (). However, in recent years, some countries, such as Brazil and the United States, are reporting increases in rates of curable STIs (). Stigma regarding STIs is prevalent in the Region () and community attributes such as poverty, substance abuse, sex roles, gender-based violence, and norms for sexual behavior affect the risks associated with individual behaviors and impede the adoption of preventive behaviors ().

The decision to move toward the elimination of STIs was agreed upon by WHO Member States in 2016 (). Most STI prevention tools and interventions have been available for years (STI case management, counseling and behavioral interventions, diagnostic tests, treatment and vaccines, etc.). However, the extent of their use varies and the adoption of innovations such as point-of-care tests, multipurpose technologies, and HPV vaccine is slow (). These interventions require targeted approaches for vulnerable populations, including youth (). The time has come to address the broader framework for sexual health to end STI epidemics. This will require interventions at not only the individual level but also the community and public infrastructure levels to address the root causes and social contexts.


In 2015, an estimated 268,500 people in the Region contracted TB, and 25,000 died (). Between 1996 and 2015, with the implementation of Directly Observed Treatment Short Course (DOTS) and the WHO Stop TB Strategy, and improved socioeconomic conditions in the countries of the Region, TB incidence dropped from 46 to 27 cases per 100,000 population (), thus meeting the TB-related MDG indicators for 2015 for the Region and the majority of its countries. This rate of decline has slowed since 2007 due to the persistence of factors linked to poverty, social inequity and exclusion, and rising urbanization, which generate living conditions and circumstances favorable to TB transmission. These difficult conditions also influence adherence to treatment among groups with poor socioeconomic status and education, regardless of disease control measures ().

Countries are committed to ending the TB epidemic (<10 cases per 100,000 population) by 2030 and eliminating TB as a public health problem (<1 case per 1,000,000 population) by 2050 (). Challenges to achieving elimination include social inequalities; demographic changes such as rapid urbanization, migration, and aging of the population; the epidemiological transition, with an increase in NCDs; and the persistence of multidrug TB and HIV transmission (), all of which increase the risk of falling ill with TB (, ). TB is concentrated in the most disadvantaged populations within the social gradient (, ), including those living in city slums, where poor housing and limited access to basic health services generate greater transmission and vulnerability (, ); ethnic minorities; migrants, prisoners; people with HIV; and those affected by NCDs (). Countries are applying different prevention and control initiatives adapted to the needs of each population. One example is the initiative for TB control in large cities () using a cross-sectoral and inter-programmatic approach, incorporating community participation and health care services adapted to the needs of the poorest.


Eighteen of the 21 countries in the Americas endemic for malaria have committed to eliminating the disease in the next 5 to 15 years (). Argentina and Paraguay have formally requested certification of malaria-free status from WHO. Costa Rica reported zero autochthonous cases since 2013 and El Salvador and Belize reported, respectively, 6 and 19 autochthonous cases in 2014. The Dominican Republic, Ecuador, and Mexico are also considered close to malaria elimination ().

As the Anopheles vector exists in almost all of the 30 non-endemic countries in the Americas, it is imperative to have surveillance and emergency response systems in place Region-wide to prevent the reestablishment of malaria transmission. Between 2000 and 2014, non-endemic countries reported an annual average of about 2,000 imported cases, mostly originating among travelers from endemic countries. Control measures in the non-endemic countries are based on travel and include preparedness for outbreaks.

In the 21 endemic countries, malaria risk depends on interactions with the epidemiologic factors (host, vector, parasite, and environment). The most important drivers of the disease in these countries are related to social determinants, occupation, geography, and the environment. Social determinants stemming from race, ethnicity, and cultural distinctions are major issues to consider in malaria elimination in key malaria-endemic areas. Many ethnic groups live in poverty, lack access to health care, and face cultural barriers inhibiting proper diagnosis and treatment. Cases from ethnic/indigenous populations were only reported by 8 of the 21 endemic countries in 2014. In Guyana, Amerindians have a fivefold higher risk of malaria than the rest of the population. Unfortunately, most other countries do not report similar types of information, making it difficult to measure risks by ethnicity, track disease trends, implement proper interventions, and make sound cases for policy change. Additional risks are related to specific occupational exposures, particularly in mining, logging, and agriculture. Miners in all countries making up the Guiana Shield are at risk of malaria with limited intervention or control methods available to them (). The approach to malaria elimination needs to be tailored to the local situation and needs to consider the social determinants in contexts where available interventions may be highly effective if implemented appropriately ().

An increasing trend of domestic funds remains the primary source of support for malaria efforts in the Region (approximately US$ 189 million in 2013) (). There are also a number of ongoing malaria initiatives in the Americas focusing on malaria elimination, including the U.S. Agency for International Development (USAID) investment to support technical cooperation on malaria control and elimination throughout the Region; the Elimination of Malaria in Mesoamerica and the Island of Hispaniola (EMMIE) initiative, funded by the Global Fund to Fight AIDS, Tuberculosis and Malaria (Geneva); and Malaria Zero (Atlanta, Georgia, United States), funded by the Bill & Melinda Gates Foundation (Seattle, Washington, United States). These and other initiatives, along with in-country resources, financial support from key partners, and technical collaboration from international agencies, provide a platform for eliminating malaria in the short to medium term.

Vaccine-preventable diseases

The Americas was the first Region in the world to eradicate smallpox, poliomyelitis, rubella, congenital rubella syndrome (CRS), and measles. With the technical support from the Pan American Sanitary Bureau and its associated Revolving Fund for Vaccine Procurement, the Region has been at the forefront of sustainable and equitable introduction of new vaccines ().

An analysis of return on investment associated with achieving projected coverage levels for vaccinations to prevent diseases related to 10 antigens in 94 LMICs during 2011–2020, based on the costs of illnesses averted, and using costs of vaccines, supply chains, and service delivery and their associated economic benefits, estimated that immunizations will yield a net return about 16 times greater than costs over the decade. Using a full-income approach, which quantifies the value that people place on living longer and healthier lives, net returns amounted to 44 times the costs. Across all antigens, net returns were greater than costs ().

As with other indicators, high national vaccine coverage levels often mask inequalities within a country. There is a clear gradient in the proportion of the population under 1 year old living in municipalities of the Americas with suboptimal coverage of DTP3 (i.e., less than 80%) along the social hierarchy defined by per capita income. Countries in the lower income quartile have an excess of almost 20% of the population under 1 year living in municipalities with suboptimal DPT3 coverage compared to countries in the highest quartile. Such excess risk of exposure is attributable to the prevailing economic inequality among countries ().

The main priorities for the Americas are (1) to ensure universal access to vaccines with emphasis on the most disadvantaged, (2) to manage the risk of reintroduction of diseases that could be brought into the Region by people traveling from other regions where the disease circulates, (3) to respond to increasing pressure from “antivaccine” groups, (4) to manage the high cost of new vaccines, and (5) to maintain immunization as a political priority, as reflected in the sustained allocation of national resources.

Neglected infectious diseases

The neglected infectious diseases (NIDs) rank with HIV/AIDS, malaria, and tuberculosis among the most common serious infections globally and in the Americas (). They are associated with poverty and marginality and have failed to receive attention, nor sufficient resources to address them, and have not historically been a priority on the public health or research agendas. They disproportionately affect populations that have been historically neglected including certain indigenous populations, Afro-descendants, and poor populations in rural and peri-urban areas. Their social determinants of health include poor housing conditions; lack of access to proper drinking water, basic sanitation, and hygiene; low income; poor education; and other barriers to access health services.

NIDs create a significant social and financial burden on poor and marginalized groups because they contribute to the cycle of poverty (). The adverse effects on the individuals include growth retardation, stunting, and impairment of cognitive development caused by soil-transmitted helminths in children, leading to decreased productivity and income in adulthood; chronic, disabling morbidity, such as chronic heart failure due to Chagas disease; disability and disfigurement caused by leprosy, lymphatic filariasis, and leishmaniasis; and visual impairment and blindness resulting from trachoma and onchocerciasis. In many cases, the chronic sequelae caused by NIDs lead to additional stigmatization and discrimination.

Many NIDs are on the path toward elimination (lymphatic filariasis, onchocerciasis, schistosomiasis, Chagas disease, leprosy, and trachoma). Others can be prevented or controlled with the appropriate tools and resources from health systems as well as government commitment and support from partners, and donors. The main challenges for elimination and control of NIDs can be grouped into two areas: (1) political and financial and (2) technical.

Political and financial challenges

NIDs are usually given a low priority in the national public health agendas due to competition with other public health-related problems, including public health emergencies, and because they affect mostly groups of people with a low political voice and their chronic nature. This diminishes the resources needed to tackle this group of diseases. This is particularly concerning because only with sustained interventions across several years can the elimination goals be reached.

Technical complexity of interventions

NIDs can be prevented, controlled, and in some cases even eliminated when health services use the proper tools and resources and have both commitment from their governments and support from partners and donors. While in some cases adequate implementation, monitoring, and evaluation of public health interventions have contributed to the successful elimination of some NIDs (e.g., preventive chemotherapy for onchocerciasis, lymphatic filariasis, and trachoma), intersectoral action in tackling the social determinants of NIDs is essential for achieving a faster, greater, and longer-lasting impact. The effective implementation of intersectoral coordination and collaboration poses a great challenge. The most cost-effective public health intervention for the control of schistosomiasis is the large-scale distribution of praziquantel, but access to healthy water, improved basic sanitation, snail control, and environmental enhancements are key to moving towards elimination. Transmission of soil-transmitted helminths and of trachoma is also closely linked to lack of access to proper sanitation, hygiene, safe water, and to lack of education on good hygiene practices such as hand and face washing and personal cleanliness. The use of proper shoes is also vital to keep children from being infected with soil-transmitted helminths.

The weakness of health systems affects the care and treatment of many persons affected by NID. Only an estimated 1% of persons with Chagas disease annually receive appropriate and timely diagnosis and treatment (). Young and middle-aged women are most likely to develop irreversible visual disabilities from ocular trachoma because of their limited access to health services, and weak health systems also contribute to delayed diagnosis of leprosy cases, with a higher risk of developing disabilities and deformities.

Changes in the environment also affect the distribution and incidence of some NIDs as occurs with visceral leishmaniasis in the Southern Cone, which is expanding due to population displacement, environmental changes, and adaptation of vectors to different environments ().

Viral hepatitis

A major shift worldwide has occurred in the significance given to viral hepatitis as a public health concern. Considered “silent” epidemics, they are now on the global health agenda with a goal of elimination as a public health threat by 2030. Of the different hepatitis virus types, the greatest burden of disease in the Americas is caused by hepatitis B and C, which contribute to more than 95% of the Regional mortality from viral hepatitis (). While the burden of other CDs has declined in the past decade, the burden of viral hepatitis has increased. National strategies for the prevention, care, and control of viral hepatitis are in place in fewer than half of countries in the Americas. The greatest strides in the Region have been in vaccination for HBV: Every country and territory has included HB vaccine in its immunization schedule for children and 69% of countries/territories have included an HB birth dose in their immunization policies. While the Region of the Americas is making gains in reducing chronic HBV prevalence, particularly from decades-long universal HBV vaccination and catch-up campaigns (), the time has come to accelerate access to care and treatment for people living with chronic viral hepatitis, particularly from HCV.

With a focus on health systems strengthening, strategies based on integrating packages of services in primary health care, including maternal and child health services, and strengthening infection control policies and practices in healthcare institutions, are key components of a sustainable and efficient public health response to viral hepatitis. Major challenges for countries include the financial investment related to prices of viral hepatitis treatment, and improving the planning, organization and delivery of services for viral hepatitis prevention, diagnosis and treatment. Price negotiation, use of generics and joint procurement strategies are solutions underway to address these issues.

Challenges for Women, Children, and Adolescent Health, including Nutritional Deficiencies

Sexual and reproductive health, newborn and child health, and nutrition in the Americas progressed in the last decade, with improvements in the national indicators and reduced inequalities among economic and educational subgroups (). Increased contraceptive use, ANC coverage and births attended by skilled personnel, decreased unmet need for family planning, decreased stunting, and decreased maternal mortality (despite not meeting the MDGs for maternal health) show a pattern of slow national improvements and a small reduction in absolute inequities in most indicators. Nevertheless, inequalities in reproductive, maternal, and child health continue and the most disadvantaged populations groups present values that the advantaged groups presented 5 to 10 years ago ().

The lessons learned from these efforts and progress are (1) the effort to assure child survival needs to be accompanied with a focus in child development; (2) achieving goals for maternal, child, and adolescent health requires addressing health sector issues, for example, those related directly to safe blood and obstetric services, and also a wider array of strategies addressing sexual health for women and adolescents, nutrition, gender, human rights, poverty and exclusion; (3) further gains will require specific approaches toward the needs of most vulnerable populations; and (4) greater attention needs to be focused on adolescent health.

Maternal mortality

Maternal health, measured by maternal mortality, remains a crucial indicator for measuring human and social development. In LAC, countries have made tremendous efforts to improve outcomes in maternal health. Between 1990 and 2015, the maternal mortality ratio (MMR) decreased by 52% in Latin America (from 124 to 69 per 100,000 live births) and by 37% in the Caribbean (from 276 to 175 per 100,000 live births) (). This decrease in MMR, however, was not enough to achieve MDG 5 (75% reduction compared to the 1990 baseline) ().

In 2015, an estimated 7,800 women died of maternal causes throughout the Region (). Most of these maternal deaths were due to complications of pregnancy and childbirth, such as bleeding, sepsis, unsafe abortions and hypertension, and the majority were preventable with quality obstetric care during pregnancy, delivery, and postpartum (). These deaths are concentrated within certain disadvantaged populations of women who face inequity in access to adequate reproductive and maternal health care services (). The link between social determinants, such as place of residence, race, occupation, gender, religion, education, and socioeconomic status, and maternal mortality is clear. In Peru, the estimate for the poorest group presented a sixfold excess maternal deaths per 100,000 live births compared with the richest quintile (). In Guatemala, the maternal mortality rate among indigenous women was more than double that of nonindigenous women (163 versus 77 deaths per 100,000 live births) ().

By looking closely at the causes of maternal mortality and morbidity, it is evident that there are economic, social and gender health inequalities that persist throughout LAC (). Women with lower socioeconomic status are less likely to have contact with the health system during pregnancy and childbirth, which are known to be periods of extreme vulnerability. On average, 90% of women in LAC have at least four ANC visits. Yet, large inequalities exist, for example, in Haiti and Nicaragua, where there is a gap of more than 30 percentage points between the poorest and wealthiest women having at least four ANC visits; for Bolivia and Panama, the gap is about 20 percentage points (2).

Some of the main barriers affecting maternal health in LAC countries in obtaining skilled birth attendance (SBA) include the lack of medical personnel in rural and low-income areas, difficult and long distances to the nearest health facilities, cost of care, and the low quality of medical treatment. As a result, a significant number of women in rural areas are less likely to deliver with SBA. In Haiti, there is a 35% gap between women living in rural and urban areas, while in Guatemala and Bolivia there are gaps of 41% and 26%, respectively (). The SDGs present a renewed opportunity to meet the challenges of maternal health and reduce the maternal health inequalities (), offering a new scenario aligning the strategy to end preventable maternal deaths ().

Neonatal, child, and adolescent health

The traditional way of describing the health situation of children () has been to present the mortality trends and the disease prevalence of the main causes of deaths for three age groups: under 5 years old, under 1 year old, and 10–19 years old. While the MDGs promoted a more integrated approach to health, the emphasis remained on mortality and on a limited set of diseases. Neonates and adolescents were barely visible, and equity was a missing component.

The region achieved MDG 4 due to the 67% decline in the under-5 mortality rate between 1990 and 2015 (). Diarrhea, pneumonia, undernutrition, and vaccine-preventable diseases as causes of mortality have decreased significantly (). However, the risk of dying shows a clear gradient: the lower in the social position the higher the risk of dying. This is the case for newborns, children, and adolescents. Most child deaths in the Region are currently either neonatal or stillbirths.

A more detailed analysis shows that the speed of mortality reduction varied by age. The annual rate of reduction was largest in the post-neonatal group, followed by the 1–5 year age group, and lower in the neonates and stillbirth (). The mortality rate of adolescents for all causes has remained stable, but the mortality rates are consistently three to four times higher among male adolescents compared with females ().

Despite international calls to address the health and social needs of adolescents, adolescent health has been overlooked. Sexual and reproductive health among adolescents is an area of political sensitivity and tension. Latin America and the Caribbean shows some decline in adolescent fertility (from 70 in 2008 to 65 births per 1,000 women 15-19 in 2014), but remains significantly higher than the global average of 45 (). Adolescent pregnancy is recognized as having profound effects on the health and well-being of young women and their children, especially for those living in disadvantage. Access to contraceptives in LAC is limited due to various legal and religious restrictions and the increasing influence of conservative groups. Child marriage is still a concern in various countries in the Region. Finally, groups such as ethnic minorities, LGBT (lesbian, gay, bisexual, or transgender) youth, those with disabilities, or who are homeless or in juvenile detention have the greatest health needs that remain invisible and unmet.

Ensuring the survival of children, their mothers, and adolescents is crucial when aiming for zero preventable deaths. Even so, country efforts to save lives are incomplete if the life prospects of those who survive remain constrained by factors that could be effectively addressed (). The process of growth and development are by nature inter-related, interdependent, and mutually reinforcing. Therefore, efforts and resources must simultaneously promote survival and development (intellectual, emotional, and social).

Globally, an estimated 7.1% of preterm babies who survive have some level of long-term neurodevelopmental impairment (). In the LAC region, an estimated 4.1 million children 3–4 years old (18.7% of the population for that cohort) experienced low cognitive and/or socio-emotional development (). The economic consequences of these and other delays are significant. Developing countries lose an estimated US$ 616.5 billion per cohort due to early life growth faltering, which is just one factor affecting child development. The losses for Latin America are estimated at US$ 44.7 billion ().

The foundations of brain architecture are laid down early in life (). Social inequities in early life contribute to inequities in health later in life (). Gender inequalities have roots in early childhood through gender socialization, gender biases, and the day-to-day experiences of a child’s early years, especially among girls.

The emphasis on early child development (ECD) is growing in the Region. The main factors driving the expansion of ECD programs are recognition of the importance of ECD and the need to increase female participation in the labor market, especially among women living in poverty. The programs vary widely in terms of their organizational structure, governance, and level of financing ().

The investment of countries in ECD services is significant. Countries such as Brazil and Chile spend annually US$ 882 and US$ 641 per child 0–5 years old, respectively (). While public spending on children 0–5 years old is estimated at 0.4% of GDP, it is two or three times higher for children 6–12 years old, in countries in Latin America and the Caribbean. In addition to lower levels of investment for younger children, it is necessary to improve the overall quality of these services. The few available studies show that full-time day care services in the Region are generally of low quality.

The health care system has an important role to play in ensuring that children and adolescents have the opportunities to thrive (). Mothers and young children seek health care more frequently than in any other period of their lives. For them, health services can serve as a platform for information, as well as a source of support and linkages with other social resources. Adolescents have the poorest level of health coverage of any age group. This fact makes the visit of an adolescent to a healthcare service a unique opportunity to address the nutritional, sexual, mental health and social changes of this age period. More than in the case of maternal and child health, progress in adolescent health will only be possible if a whole of society approach is at the center of country efforts.

Nutritional deficiencies

The nutrition landscape in the Americas is undergoing change in all countries and in most population groups as a result of changes in the food environment that affect diet and eating practices. The Americas met the MDG 1 target related to underweight prevalence in children under 5, but undernutrition in the form of stunting in young children continues to be highly prevalent in many countries, particularly in Central America and the Andes (). There are large differences within and among countries, with indigenous and Afro-descendant children and those living in rural areas especially affected. Stunting is a predictor of lower educational outcomes and adult productivity and a risk factor for subsequent overweight and associated metabolic disorders. Wasting is far less prevalent and focused in specific high-poverty communities. Overweight and obesity are similar in women and adolescents and among all income and ethnic groups. In some households, child stunting and maternal overweight coexist ().

Between 1990 and 2014, the prevalence of stunting among children less than 5 years of age in the Region decreased from 14.9% to 7.1%. However, it remains above 25% in two countries and above 15% in six more. A traditional approach to reduce stunting has been to provide complementary foods, which has met with limited success. A more innovative approach is to provide conditional cash transfers/or comprehensive and integrated programs to address its root causes of poverty and other social determinants. Brazil and Mexico have been particularly successful with this approach and have significantly reduced not only the prevalence of stunting but also inequities among the affected population subgroups. At the same time, such programs have led to increases in overweight in women and need to be carefully monitored and adjusted to not reduce one nutrition problem while exacerbating another ().

Micronutrient deficiencies, particularly iron deficiency, continue to be a problem among women, children, and adolescents, and rates are especially high among children under 2 years of age and pregnant women. Staple food fortification, such as salt iodization and fortification of sugar with Vitamin A has proven effective in reducing deficiencies of these micronutrients. However, the reduction of iron deficiency and deficiency of other key micronutrients through supplements and food-based approaches is challenging. As the reduction in the consumption of salt and sugar to prevent obesity and/or NCDs becomes increasingly important, adjustments to staple food fortification programs will be needed ().

Given the rapid changes in the nutrition landscape in which undernutrition coexists with overweight and obesity, the increases in child, adolescent, and maternal overweight and obesity, and persistent micronutrient deficiencies, efforts to improve food and nutrition security must be addressed through comprehensive multisectoral actions that simultaneously address malnutrition in all its forms. While alleviating poverty and other social determinants, actions are also needed in the agricultural sector to improve access to nutritious foods. Regulatory actions are necessary to improve the food environment to promote the consumption of minimally processed foods such as fiscal policies, regulation of food marketing and front-of-package labeling ().


In all countries of the Americas, maternal and child mortality and the burden of CDs have decreased in the past 5 years. Nevertheless, inequities persist in the Region, and LMICs experience worse health outcomes, including higher mortality and morbidity related to CDs and other diseases and conditions that affect mothers and children. Re-strategizing the approach to sustain the gains in MDGs 4, 5, and 6 and address complex issues of this unfinished agenda will be part of the transition to the 2030 Agenda. Countries and development partners need to acknowledge that while chronic diseases are increasing, the burden of CDs and maternal and child deaths including those related to nutritional deficiencies is still considerable.

The Region of the Americas has moved into a period of emergent infectious diseases due to changes in environment, lifestyle, and travel. These conditions can lead to the evolution of new pathogenic arboviruses and others, meaning that timely notification of public health events with potential international impact and future disease control strategies must recognize this context and plan accordingly. Vaccine development, innovative technologies, new drugs, and research programs are some of the areas recommended for collaboration among different sectors, including public sector partners such government health, education, agriculture, and urban development departments and private sector partners such as industry, academia, and civil society.

A focus on health, education, and socioeconomic disparities is needed in order to close the gaps and leave no one behind in working to achieve the SDGs—particularly in the elimination of HIV, malaria, NIDs, STIs, TB, and viral hepatitis and the improvement of maternal, child, and adolescent health.


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1 Health events that endanger international public health, as defined by the International Health Regulations (IHR) (2005), an agreement between 196 countries including all WHO Member States.

2 An online WHO application tool designed to provide timely information for event monitoring and iterative risk assessment and support decisions about response operations during outbreaks and other acute public health events in accordance with the IHR [].

3 While elimination is based on interruption of transmission to zero or very low levels, the specific definitions of elimination vary depending on each disease and its control measures.

4 Key populations refer to both vulnerable and most-at-risk populations for HIV infection. They are important to the dynamics of HIV transmission in a given setting and are essential partners in an effective response to the epidemic (WHO. 2013. HIV/AIDS: definition of key terms. Available from:

5 See

6 Persons under the age of 18 years.

7 MDG 4: Reduce by two-thirds, between 1990 and 2015, the under-five mortality rate.

8 Defined by WHO as people between 10 and 19 years old.

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