Health Status of the Population
- Yellow Fever
- Antimicrobial resistance
- Full Article
Cholera in the Region of the Americas, 2010–2016
Cholera still persists in the Americas. From 2010 to 2016, cholera was reported in Cuba, Dominican Republic, Haiti, and Mexico (Table 1).
In Haiti, Vibrio cholerae O1 has been present since 2010. Epidemiological peaks are observed during rainy periods due to increased water run-offs, feeding the endemic transmission (Figure 1). The endemic cycle is maintained through the mobility of persons and inadequate hygienic practices. Oral cholera vaccine was introduced in 2015, and approximately 373,000 persons were vaccinated. Even so, sufficient investment in sewage infrastructure is needed to counter the current endemic cholera situation in Haiti.
Figure 1. Cholera cases per week in Haiti, October 2010–November 2016
* Dates are mid-day of respective epidemiological weeks.
Source: Data from the national surveillance system, MSSP, Haiti.
The Dominican Republic and Cuba reported cholera cases related to Haiti’s outbreaks. The differences in terms of health services infrastructure, sanitation conditions, and access to safe water help explain differences in the spread of cholera among these countries. Mexico also had a cholera outbreak related to the Haitian strain between 2012 and 2014 ().
Table 1. Cholera cases by selected countries in the Americas, 2010–2016. Data from PAHO* unless specified in the footnotes below.
* PAHO. Epidemiological update: cholera. 27 May 2016. Available from: https://www.paho.org/hq/index.php?option=com_docman&task=doc_view&Itemid=270&gid=34811&lang=en.
^ Data for 2010 to 2014 obtained from the WHO Weekly Epidemiological Bulletins. Available from: http://www.who.int/wer/en/.
# Data for 2015 provided to PAHO/WHO by the respective national authorities.
& Data from 1 January to 30 April 2016.
From 2012 through 2016, the patterns of influenza circulation varied by year and by subregion (Figure 1).
Figure 1. Influenza circulation by subregion of the Americas, 2012–2016
In North America, where influenza seasons typically peak around the beginning of the calendar year, during the 2012–2013 and 2014–2015 influenza seasons, influenza A(H3) virus predominated. These H3-predominant seasons are typically associated with higher morbidity and mortality, especially among the elderly.
During the 2013–2014 and 2015‐2016 influenza seasons, influenza A(H1N1)pdm09 predominated.
In the Caribbean, the 2012 season differed from other seasons in this subregion, with an early predominance of influenza A(H3), followed by prolonged circulation of influenza B. The 2013, 2015, and 2016 seasons were similar, with an early predominance of influenza A(H1N1)pdm09 followed by later circulation of influenza A(H3). In 2014, influenza circulation was low overall in this subregion, with an end-of-year increase in influenza A(H3) activity.
In Central America, each season in the 2012–2016 time period had a different pattern, owing largely to the variability in influenza circulation by country. Much like the Caribbean during 2012, there was early circulation of influenza A, in this case A(H1N1)pdm09, followed by prolonged circulation of influenza B. During 2013, 2015, and 2016, influenza A(H3) circulated, but in conjunction with influenza B (2014) and influenza A(H1N1)pdm09 (2013, 2015, and 2016).
In the Andean subregion, the overall patterns resembled those of Central America with some notable differences. In the Andean subregion, influenza (H1N1)pdm09 predominated during the 2012, 2013, and 2016 seasons, and during the 2014 season, co-circulated at a low level overall with influenza A(H3).
In the Southern Cone, influenza circulation patterns were similar to those in Central America and the Andean subregion during 2013 and 2016. During 2012, 2014, and 2015, influenza A(H3) circulation was followed by low-level influenza B circulation, as is typical of a temperate-climate influenza season. During 2012 and 2015, however, influenza A(H1N1)pdm09 co-circulated with influenza A(H3), but at a low level.
Yellow fever is a vaccine-preventable hemorrhagic fever caused by a single-stranded RNA flavivirus and transmitted by mosquitoes according to two distinct epidemiologic patterns. Aedes aegypti, the same mosquito species responsible for transmission of the dengue, chikungunya, and Zika viruses, also transmits urban yellow fever, the classic epidemic form of the disease. Haemagogus and Sabethes species of mosquitoes, which typically spend their winged lives in forest canopies, can transmit jungle (or sylvatic) yellow fever to nonhuman primates and occasionally to humans, causing sporadic cases that can then reintroduce the disease into urban areas. Jungle yellow fever remains an important health threat in the Region. With the growing influence of climate change, and compounded by humans encroaching on jungle areas, the risk of transmission to humans and thus of occurrence of an urban cycle of yellow fever has become more pronounced. Furthermore, recent outbreaks of Zika virus and chikungunya confirm that the wide distribution and high infestation rates of Aedes aegypti in many highly populated cities are conducive to efficient transmission of Aedes-borne arboviruses.
Figure 1. Areas at risk of yellow fever in the Region of the Americas, 2013–2016
Yellow fever has historically been known to circulate in the Americas in areas of Argentina, Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Panama, Paraguay, Peru, Suriname, Trinidad and Tobago, and Venezuela. However, the range of the virus continues to expand (Figure 1). From 2010 to 2016, 269 confirmed cases of yellow fever were reported to the Pan American Health Organization (Figure 2), with an average of 48 cases per year ().
Figure 2. Confirmed cases of yellow fever in the Region of the Americas, 2010–2015
Brazil reported an outbreak of yellow fever at the end of 2016. Between 1 December 2016 and 17 March 2017, a total of 448 confirmed yellow fever cases had been reported, including 144 confirmed deaths (for a case fatality rate of 32%). The outbreak has affected the following eight Brazilian states: Bahia, Espírito Santo, Goias, Minas Gerais, Rio Grande do Norte, Rio de Janeiro, São Paulo, and Tocantins ().
In the 21st century, infectious diseases continue to cause morbidity and mortality in the Region of the Americas. While the development of antimicrobial resistance by microbes (bacteria, viruses, parasites, fungi) is not a new phenomenon, the awareness of its importance, not only for health but also for the economy and human development, has recently reached an unprecedented level. At the 69th United Nations General Assembly, held in September 2016, world leaders committed to acting on antimicrobial resistance, calling for a multisectoral response and appealing to organizations such as the World Health Organization (WHO), the Food and Agriculture Organization of the United Nations (FAO),and the World Organization for Animal Health (OIE), along with other stakeholders such as multilateral development banks and civil society, to use the “One Health” approach in responding to antimicrobial resistance (). In efforts to meet the commitment made during the 69th United Nations General Assembly, five of the Region’s countries are in the process of preparing and implementing national and multisectoral plans to respond to and contain antimicrobial resistance.
For more than two decades, Latin America has employed the Latin American Surveillance Network of Antimicrobial Resistance (ReLAVRA). From 1996 to the present, a growing trend of resistance among the principal human pathogens, including community and hospital pathogens (pneumococci, gonococci, Staphilococcus aureus, and enterobacteria), has been documented (). Some countries in the Region are organizing programs for integrated monitoring of antimicrobial resistance in order to follow the evolution of antimicrobial resistance and propose measures to limit its growth. This effort is being supported by ReLAVRA, the Global Foodborne Infections Network (WHO-GFN), and the Pulsenet Latin America and Caribbean network. The purpose of these programs is to generate descriptive data and identify trends regarding patterns of sensitivity or resistance in zoonotic pathogens, foodborne pathogens, and a select group of commensal organisms in order to identify unusual or high levels of resistance to antimicrobial drugs in humans, animals, and foods containing these organisms.
Surveillance systems have made it possible to document the spread of emerging mechanisms of resistance in the Region. Between 2011 and 2016, KPC-type carbapenemas spread in almost all of the countries of Latin America. This mechanism causes high case fatality (up to 50%) in outbreaks at intensive care units (). Evidence has also been found of the presence and spread of other emerging mechanisms of resistance in enterobacteria (such as OXA-type carbapenemases, NDM-1 New Delhi metallo-beta-lactamases, and resistance to colistin mediated by plasmids [mcr-1]) (Figure 1).
Figure 1. Identification of emerging resistance mechanisms in enterobacteria, Region of the Americas, 2000–2016
Multiresistant fungi can also cause hospital outbreaks. Since 2012, Candida auris outbreaks caused by Candida have been reported in intensive care units in Venezuela, Colombia, Panama, and the United States (). Case fatality in these outbreaks can reach 30%. The correct and timely detection of C. auris is essential as the organism is often confused with other species (e.g., C. haemulonii).
The road ahead: the molecular epidemiology of resistance
Molecular epidemiology makes it possible to recognize genetic characteristics of microorganisms, which assists in ascertaining patterns of clonal dissemination and in identifying emerging resistance mechanisms. In recent decades, the technology required to conduct regional studies in molecular epidemiology has become increasingly accessible. In 2016, an initial extensive study of mechanisms of resistance to fluoroquinolones in Salmonella enterica was conducted. The study examined the regional situation regarding mutations in DNA gyrase – the most important mechanism of resistance to fluoroquinolones in the Region – as well as indicating the presence of mechanisms mediated by plasmids.
As a result of molecular studies, the presence of the mcr-1 gene (which provides resistance to colistin) has been detected in isolations of Escherichia coli from Argentina, Colombia, Ecuador, and the United States. These findings underline the importance of integrated monitoring of resistance, since the use of colistin in veterinary medicine selects for this gene. Coordination between the human and animal health sectors is key to preventing and controlling transferable colistin resistance in microorganisms ().
In implementing national plans to address antimicrobial resistance, countries should adopt actions consistent with, and realistic within, the context of national circumstances, needs, and priorities. The goal is to ensure that there exists the capacity to treat and prevent infectious diseases through the responsible and rational use of effective, safe, available, accessible, and quality-assured drugs.
Between 2010 and 2016 there were 3,311 disasters worldwide, of which 682 (20.6%) occurred in the Region of the Americas (Table 1), at a cost of US$ 300 billion. Of the 815,111 injuries and 160,962 deaths caused by disasters across the globe, 277,037 and 12,954, respectively, occurred in the Region. Of the 400 adverse events in the Region, 58.6% involved hydrometeorological phenomena, at a cost of approximately US$ 278 million ().
Table 1. Global impact of natural disasters on health and impact on the Region of the Americas, 2010–2016
|Damages (US$ thousands)||903,828,410||296,438,667||32.8|
Source: Adapted from EM-DAT. Database of the Center for Research on the Epidemiology of Disasters (CRED) ().
Earthquakes in Haiti and Chile in 2010 and in Ecuador in 2016 caused significant damage to the health sector, particularly infrastructure, leading to a reduced capacity to provide effective care for the population.
Nearly 30 of Haiti’s 49 hospitals collapsed or were damaged, representing losses of around US$ 470 million; 90% of primary health care facilities remained standing or were less severely affected ().
In Chile, there was a loss of 4,249 hospital beds, including 22% of the total available beds at affected health care facilities in the Bío Bío, Metropolitan, and Maule regions. In addition, 39% of the operating rooms in the affected area were compromised. The greatest impact was in the Araucanía, Maule, and Bío Bío regions (). Damages in the health sector have been estimated at US$ 2.72 billion ().
In Ecuador, the earthquake of 16 April 2016 rendered 48 health care facilities inoperative, including 12 health care centers, 6 clinics, and 3 general hospitals. A total of 537 hospital beds were removed from operation, representing 29% of the available beds at in-patient facilities. The Government of Ecuador calculated the cost of reconstruction in the health sector at US$ 177.9 million.
Since the greatest effect of the damage to hospital infrastructure has been a reduction in the capacity to save lives, the ongoing challenge is to ensure that hospitals are equipped to continue functioning in the wake of an adverse event. Programs promoting hospitals that are safe, “smart,” and environmentally friendly exemplify the best available strategies for responding to the challenges posed by emergencies, disasters, and outbreaks or epidemics, by maintaining response capacity and ensuring timely health care.
At the same time, health systems that are more capable of withstanding emergencies and disasters must be created, and the internal response capacities of the countries must be strengthened, along with the capacity for coordination and cooperation between countries.
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