Shifts in the illegal drug trade and the rise of the Northern Triangle

Chris Beyrer and his colleagues have pointed out how during the 1990s and 2000s, internal armed conflicts, guerilla movements, kidnappings, and internal displacements linked to cocaine production and trafficking largely halted public health, vector control, and case-detection and treatment activities in Colombia [7]. As a result, there was a sharp rise in malaria, Chagas disease, and leishmaniasis cases [7]. As we moved into the 2010s, drug smuggling routes shifted away from the Caribbean and Florida towards Central America, with major routes operating through the Northern Triangle nations of Guatemala, El Salvador, and Honduras [8]. Briefly, the three countries in the Northern Triangle each face recent and dramatic increases in widespread criminal activity (including organized crime, extortion, forced recruitment into criminal groups, sexual and gender-based violence, and violence against children) as well as economic hardship [2]. New drug routes through the Northern Triangle help to fuel transnational gangs such as Mara Salvatrucha (MS-13) [8]. The rise in violence in this region, together with failed economic policies leading to some of the largest income disparities in the Americas, generated large population displacements now producing large migrant human caravans through Guatemala and Mexico [9]. The public health impact of this political instability and its role in stimulating the rise of NTDs and vector-borne disease in the Northern Triangle remains largely unstudied. However, the impact can be devastating as seen from the spring and summer of 2019 dramatic uptick in dengue cases and severe dengue that was observed in the Northern Triangle countries, especially Honduras and in Nicaragua [10]. Chagas disease, leishmaniasis, and even many of the helminth infections actually increased over the last two decades, so overall within the CLA region, the Northern Triangle countries have made some of the least progress in NTD control, possibly second only to Venezuela.

Political instability and socioeconomic collapse

An equally urgent economic and humanitarian crisis has unfolded in Venezuela over the last decade. Specifically, the Bolivarian revolution, steep drops in oil revenue, and rise in illegal mining have effectively shut down many aspects of Venezuela’s public health system, with a disproportionate impact on vector-borne tropical diseases and interruption of control activities [11]. Among the prominent aspects is a greater than 400% increase in malaria cases in Venezuela since 2000, together with significant rises in Chagas disease, leishmaniasis, and dengue and the emergence of chikungunya and Zika virus infections [11, 12]. Schistosomiasis increases have also been noted [12]. Similar to the migrant caravans in Honduras, the socioeconomic collapse of Venezuela has fueled a massive population exodus into Brazil, Colombia, and Ecuador, potentially spreading vector-borne diseases.

The Central American Dry Corridor and climate change

Sociopolitical and economic breakdowns in Venezuela and surrounding countries or in the Northern Triangle of the CLA region are not occurring in isolation. Regarding the Northern Triangle, five years of drought (often interspersed with drenching rains)—in an area that extends from southern Mexico and Guatemala through Honduras and El Salvador and possibly extending as far down as Panama—has produced a Central American “dry corridor” that has adversely affected agriculture in the region, promoting food insecurity, malnutrition, urbanization, and human displacements [13]. The dry corridor is believed to have developed and expanded due to Central America’s disproportionate vulnerability to climate change [3], which can also promote susceptibility to vector-borne tropical diseases, particularly for illnesses transmitted by urbanized Aedes aegypti mosquitoes. It’s been further noted that a mysterious form of kidney failure known as Mesoamerican nephropathy has emerged in the dry corridor, where it is sometimes known as global warming nephropathy [14]. Outside of Central America, severe drought from climate change similarly affects Venezuela [15].

Marginalization of indigenous populations

Indigenous populations are at disproportionate risk to NTDs due to lack of healthcare, extreme poverty, and the fact that their native lands are often exploited for mining and other causes of environment degradation. Such situations are now unfolding among the Yanomami indigenous people in the Amazon region of Venezuela and Brazil, the Wayuu in La Guajira in Colombia near the Venezuela border, and possibly others [16].

Concluding comments

Together, the countries of the CLA region contain several areas of “perfect storm” conditions (areas highly vulnerable to NTDs, especially vector-borne illnesses). The vulnerability stems of the combination of key physical and social determinants acting together, often synergistically. (Fig 3).

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Fig 3. The key vulnerability points and challenges that influence and stall the progress of neglected tropical disease control in the CLA region.

CLA, Central Latin American; NTD, neglected tropical diseases.

https://doi.org/10.1371/journal.pntd.0007962.g003

The decline in health systems resulting from these vulnerability points likely account for the minimal public health gains and reductions in NTDs seen over the last two decades. However, it should be noted that progress has been achieved in some areas. For example, Mexico has achieved great progress in terms of the control of malaria, leishmaniasis, and soil-transmitted helminth infections while eliminating onchocerciasis over this period, although Chagas disease and cysticercosis continue to rise and the incidence of dengue has increased dramatically. Similarly, Colombia has made important public health gains in malaria and soil-transmitted helminth control these past two decades, although cases of Chagas disease, leishmaniasis, and dengue continue to go up. Both Venezuela and the Northern Triangle countries continue to have serious challenges leading to—in some cases—tragic increases in their NTDs and, in the case of Venezuela, even a steep rise in malaria. Therefore, additional research is urgently required to understand the marked heterogeneity in NTD and malaria control across the CLA region. Doing so will help identify potential solutions to pinpoint which interventions are effective or which new global heath technologies will need to be developed.

Agencies such as the Organization of American States (OAS) and the Pan American Health Organization could have an important role in convening experts for this purpose. One aspect, for instance, that could accelerate research and development of new or improved global health technologies is building local pharmaceutical development capacity in the CLA region, potentially in Mexico, Panama, and/or Colombia where some infrastructure for biotechnology already exists. This would allow for future self-reliance, sustainability, and economic strengthening while developing and testing new or better drugs, vaccines, and diagnostics specifically designed for the major neglected diseases impacting this troubled part of the world. Nevertheless, getting to the root social and physical causes of the CLA region’s vulnerability points will be paramount for long-term and sustainable solutions to its health system collapse and disease emergence.