Why ‘tropical disease’ is a global problem

In 2015, the United Nations agreed upon Sustainable Development Goals  which set seventeen ambitious targets for the next two decades focusing on tackling poverty, reducing disease, protecting the environment, and driving forward an international community based on sustained commitments to – and improvements in – education, health, human rights, and equity. At first glance, infectious diseases in the tropics do not make headlines among the seventeen goals. On closer scrutiny, however, tropical medicine epitomizes issues that are woven into the heart of this sustained global initiative, and that are relevant to all of us with an interest in 21st century health, wherever we live and work.

Among the seventeen goals, ‘good health and well being’ (goal 3) is the most obviously relevant to tropical medicine, with a bold statement that sets out an agenda to be achieved by 2030, to ‘end the epidemics of AIDS, tuberculosis, malaria and neglected tropical diseases and combat hepatitis, water-borne diseases and other communicable diseases’. Within this goal are additional targets, including provision of sexual health services and access to essential vaccinations.

‘Clean water and sanitation’ (goal 6) is crucial for health and wellbeing in ways that are obviously fundamental and is pertinent to curbing the spread of waterborne diseases including hepatitis A, cholera, and typhoid. Less well recognized diseases are also tackled within this aspiration, including schistosomiasis (blood flukes) and dracunculiasis (‘guinea worm’).

Tropical and subtropical regions are particularly vulnerable to the spread of infectious diseases – the perfect storm arising from the intersection of poor sanitation, lack of education, inadequate resources and infrastructure for healthcare, and specific climates and environments. At the root of this all is poverty. ‘No poverty’ (goal 1) includes an aspiration that individuals, families, and society have sufficient reserves and resource to cope with a crisis – to access drugs and healthcare, and to continue to provide for their children throughout periods of instability arising from illness. Implicit in the aim for economic growth (goal 8) is the need to have a population of adults who are well enough to be economically active in contributing to productivity, development, and prosperity.

‘Quality education’ (goal 4) highlights a particular need to focus on girls and women, whose education is often neglected but whose literacy is known to impact significantly on the health of their children. Education is empowering per se, but also provides a specific foundation for women to become active participants in vaccinating their families, taking measures to prevent mother-to-child transmission of infection, compliance with therapy, promoting and developing better sanitation, and improving sexual health. Tackling inequality is such a key issue that it is also independently represented within goals 5 and 10.

So how, and why, are these challenges aimed mostly at low and middle-income settings relevant to affluent, developed countries?

One answer is that we are part of a delicate global community, in which the health and wellbeing of all human populations is interdependent. In other cases, numbers provide a powerful answer to the question: in Africa, malaria still kills over 290,000 children every year – that is a child every two minutes. None of us should absolve ourselves of responsibility for continued investment in tackling this humanitarian tragedy.

But there are other answers: we are all vulnerable to threats which wreak their worst effects in the tropics – organisms like Streptococcus pneumoniae (a cause of pneumonia) and E. coli (a cause of diarrhoea and urinary tract infections) are common the world over.

The Ebola virus, arising out of a tropical situation, was in no way confined by the bounds of Cancer and Capricorn; it had the potential to take hold in situations of poverty and limited infrastructure and then to spread fast, facilitated by its huge infectivity, and fuelled by human behaviour and environments including crowding, migration, and international travel. Other organisms, like cholera, measles, meningitis, and polio rear their heads in disaster situations; in a world so uncertain, none of us knows when this is around the next corner.

Changes in climate and the environment allow creatures that are the reservoirs and vectors of infection to spread to new locations; the concern for the Zika epidemic in South America has been its rapid dissemination by a mosquito that has the potential to become ubiquitous. The spread of organisms that are resistant to multiple drugs is another major threat to global health. One example is Mycobacterium tuberculosis, the organism that causes TB, where multi-drug resistant (MDR) and extensively-drug resistant (XDR) strains are now well-established. Associated with a high burden of disease, high death rates, and difficult, expensive treatment, these organisms are by no means confined to the tropics.

And what about financial security? We value crops like tea, coffee, chocolate, and bananas which are the exclusive preserve of tropical and subtropical farmers; our supplies depend on their health and productivity. Rich natural resources – from coal to gold – are mined from these regions of the world, and the manufacturing, clothing, and electronics industries are built on tropical and subtropical manpower.

Infections that flourish in the tropics continue to cause a catastrophic burden at the level of individual patients, their families, and wider society at national and international level. They impose an enormous economic cost upon healthcare systems and society, related both to providing care and to the lost output of young adults who are unable to contribute to society through work or raising their families. Labelling them as ‘tropical’ identifies a strong association with some of the world’s most vulnerable settings – but perhaps we need to move on from the term ‘tropical medicine’ to considering ‘global health’

Despite being open to criticism for being too broad, too ambitious, too expensive, the Sustainable Development Goals do put emphasis on tackling the cause of problems rather than just trying to fix the end result. In order for our planet and its populations to thrive and flourish, the aims represented are crucial. The health, well-being, and future of our children and grandchildren are tightly bound to these bold aspirations, and the strides we make against ‘tropical diseases’ represent steps forward for us all.

Featured image credit: Street by aamiraimer. CC0 Public Domain via Pixabay.