The Ecology of Health

The complex interactions between humans, animals, and the environment have become more apparent in the past few decades. This is because of emerging infectious diseases, environmental hazards, ecological degradation, and climate change, all of which affect the collective health of our world. Rapid urbanisation and habitat fragmentation have increased our interactions with bats, non-human primates, and feral dogs, which in turn have impacted the health of local communities and led to the emergence and spread of diseases such as Nipah virus, Ebola, HIV, and rabies. The distribution and prevalence of vector-borne diseases such as dengue, malaria, and Lyme disease have been compounded by unchecked urban expansion, changes in land use and climate change.  A rapidly growing human population has led to the extensive industrialisation of agriculture and animal husbandry—increasing our exposure to hazardous contaminants (mercury, lead, DDT)—and the widespread use of antibiotics, which has led to increasing antimicrobial resistance in pathogens.

Therefore, to address the complex problems we face today in public health, we require a collective approach that spans across environmental, animal, and human sectors. An example of such an approach, which emphasises the need for transdisciplinary partnerships and multisectoral collaborations for optimal health outcomes, is ‘One Health’. Keeping the wider planetary health in mind, the ‘One Health’ approach can enable us to predict, mobilise, and mitigate challenges  such as antimicrobial resistance, food insecurity, pandemic unpreparedness, species extinction, and ecological degradation.

Elements in the artwork:

The purpose of the drawing is to visualise the interconnectedness between a healthy environment, humans, and other animals—all represented in a circle. Through the artwork, I highlight the major actors which have shaped my personal understanding of these interconnections:

  • Health professional: In order to express the theme of health, I deemed it necessary to include health professionals and their role in understanding, mitigating, and controlling emerging infectious diseases and other health issues.
  • Hooded Figure: Gender has important effects on the determinants and consequences of health, especially in developing and industrialised countries. Women are more vulnerable to diseases and epidemics due to gender norms, inaccessible and biased healthcare services, unprepared health systems, and power dynamics. Apart from women, children, immunocompromised individuals, BIPOC communities, and low-income individuals are also extremely vulnerable to, and impacted by infectious and non-infectious diseases, and environmental hazards.
  • Child and chicken: Modern agriculture, food production practices, and changing dietary patterns have increased the incidence of various types of infectious disease such as Salmonella, exposure to contaminants, and antimicrobial resistance in industrialised nations. Salmonella infections commonly occur in children, where risk factors include living in a rural area, contacts with pets, and consumption of  untreated local water.

While taking classes in Wildlife Disease Ecology and One Health during my undergraduate studies in Wildlife Biology at the University of Vermont, I was presented with various case studies that included many of the species I have incorporated in my artwork. In addition to this, my reason for choosing these species was because they are widely recognized in India, which is where I’m from:

  • Feral dogs: Feral dogs can threaten the health of wildlife, domesticated animals as well as people. Free-ranging feral dogs are reservoirs for many zoonotic diseases that can spread to other species, such as canine distemper virus, rabies, and brucellosis.
  • Leopards and big cats: Big cats are increasingly coming into contact with humans, domesticated animals, and feral dogs due to urbanisation, habitat loss, and tourism. These interactions may pose a risk to the conservation of big cats due to the potential spread of disease between species. However, positive impacts of wildlife such as vultures and big cats in controlling zoonotic transmission have also been recorded, such as a recent study that determined the role leopards play in controlling transmission of rabies between stray dogs in Mumbai and its citizens. 
  • Non-human primates (NHP): Many infectious diseases in humans have been linked to NHP. NHP have a variety of micro- and macro-parasites which increase the chances of cross-species transmission with humans (and vice-versa). This can cause new pandemics as well as threaten endangered populations of various NHP. In India, langurs and macaques are common NHP  who live in close proximity to humans, which results in important health implications for both. I drew a langur holding a plastic bottle to symbolise this very proximity.
  • Ticks and mosquitoes: According to the World Health Organisation, vector-borne diseases account for more than 17 percent of infectious diseases. Among the various vectors, arthropod vectors are the most common and responsible for infectious diseases, such as malaria, dengue, yellow fever, Zika virus, and Lyme disease. Moreover, vector-borne diseases are linked with the health of the environment. For example, climate change and rising temperatures are causing range shifts of various vectors such as ticks, which is leading to an increase in the prevalence of Lyme disease in habitats it was not seen in before.
  • Snakes and frogs: In many cases, changes to ecological health are not very obvious to people. However, sensitive groups such as amphibians are good indicators of ecological integrity. Additionally, increased contact with reptiles and amphibians increases zoonotic disease transmission associated with bacterial infections like Salmonella, Mycobacterium, E. coli, etc.
  • Bats: Recently, bats have been subjected to negative publicity because they are natural reservoirs for various high-profile zoonotic viruses such as paramyxoviruses, coronaviruses, Nipah and Hendra viruses. However, I believe this emphasises our need to understand and thus mitigate harmful interfaces between domestic animals, humans, and bats, which are crucial for maintaining ecosystem health—as they pollinate plants, disperse seeds, and control insect populations.
  • Hornbill: Ecosystem health and resilience are essential for maintaining populations of endangered wildlife, such as hornbills, which are severely threatened by habitat destruction, habitat loss, and hunting.
  • Trees, plants and fungi: These elements characterise the environment, on which both wildlife and people depend for the ecosystem services they provide.
Illustration by Soham Mehta, Ball-point pen ink on paper

Further reading:

Kahn, L. H. 2017. Perspective: The one-health way. Nature 543(7647): S47–S47.

Capos. C. 2021. One Health: preventing and solving public health disasters. University of Michigan School of Public Health Findings 37(1): 22–29.

Halliday, J. E., K. J. Allan, D. Ekwem, S. Cleaveland, R. R. Kazwala and J. A. Crump. 2015. Endemic zoonoses in the tropics: a public health problem hiding in plain sight. Veterinary Record 176(9): 220–225.