Figure 1.

One health disparities. The top of the figure illustrates a standard view of One Health and zoonotic disease in the context of SARS-CoV-2. Bats represent the likely reservoir of SARS-CoV-2, with transmission from bats to humans occurring directly or through bridge hosts (amplification hosts), such as livestock or animals in wet markets. Once in the human population, the virus successfully infected multiple new animal species, including mink, and other species are likely to be susceptible, such as other great apes. The bottom of the figure integrates One Health, social determinants of health, and health disparities within a framework of exposure, susceptibility and disease expression. We represent the social environment and exposure with a social network, revealing a gradient in exposure (top to bottom) that results in exposure disparities. Susceptibility and disease expression are combined here, given that they are difficult to disentangle without experimental studies, and also shown as a gradient (left to right). This results in a gradient of susceptibility and disease expression disparities. The figure shows an expected correlation between exposure and susceptibility-disease expression. However, outliers to this expected correlation will occur. For example, individual (a) is someone who has high exposure but low susceptibility (such as a healthcare worker) and individual (b) is someone who has high susceptibility but low exposure (such as an older person with comorbidities who is able to work from home to reduce exposure).