Despite the continuous advances in medicine, public health, and general health science, emerging infectious diseases (EIDs) continue to become more frequent in the last few decades (Ellwanger, 2019). just think about all the outbreaks, epidemics, and pandemics that have emerged in the 21st century: SARS, H1N1, MERS, Ebola, Zika virus, Covid-19, and now Monkeypox. One might think that the advances in medicine and public health might counteract the increased international mobility of the worlds occupants. However, it is not that simple. Although advances in medicine in the past few decades have been profound there has been a disproportionate increase in factors that allow for EIDs: the loss of biodiversity among other environmental changes, poor public health systems in many countries, and the resistance to antibiotics to name a few.
Funding in the field of global health is complicated given that the funds are often scarce. This is especially true in low-income countries that often need funding the most. Ellwanger et al. published an article in the Journal of Infection and Public Health where they lay out a simple map of where and how these funds should be allocated so as to provide the highest efficiency for combating EIDs.
In this figure, it shows 3 major areas of consideration when tackling EIDs: animal reservoirs (Exploration), human sentinels (Surveillance), and general human population (surveillance). It is important to not only know how each of these areas contribute to the emergence of candidate pathogens, but also how they contribute to public health funding.
The first area focuses on the investigation of known and unknown microorganisms residing animal hosts. Animal reservoirs are the starting line from which all zoonotic transmissions (transmission from animal to human) originate. In a perfect world, anytime an EID pops up we would determine the pathogen and already have its genome sequenced leading to rapid development of a therapeutic vaccine. However, obtaining this pathogenic information is costly. Additionally, the large majority of pathogens residing in wild animals will never lead to any sort of zoonotic transmission (Lloyd-Smith, 2017). Nevertheless, that pathogenic data could be the difference between a small isolated outbreak and a full blown pandemic. It should then be concluded that focusing investigation on candidate hosts (domesticated animals, livestock, and of course bats) would lead to the highest efficacy.
The final two areas revolve around surveillance. This essentially means that instead of exploring possible pathogens that might make the jump, we are now focused on surveilling the microorganisms that are already present in humans. The human sentinel for spillover area refers to individuals who are in close and frequent contact with animals and livestock. Such individuals include veterinarian, farmers, and hunters. These individuals are important for surveillance as they are likely already host to microorganism that have been zoonotically transmitted. General human population surveillance acts to survey blood donor samples for specific pathogens. These pathogens being searched for would be determined by the 2 previous areas. Such detection techniques require an adequate laboratory and an educated staff. These might be serious limitation in low-income countries.
In a post-pandemic era, it is imperative that we put in place efficient methods for detecting EIDs. Early detection of EIDs can make a drastic change in terms of response and mitigation of spread. Three important areas for funding in terms of cost-efficiency are exploration of animal reservoirs and surveillance of human sentinels and general human population.
Primary Article
Ellwanger, J. H., Kaminski, V. de, & Chies, J. A. B. (2019). Emerging infectious disease prevention: Where should we invest our resources and efforts? Journal of Infection and Public Health, 12(3), 313–316. https://doi.org/10.1016/j.jiph.2019.03.010
Other Resources
Lloyd-Smith, J. Predictions of virus spillover across species. Nature 546, 603–604 (2017). https://doi.org/10.1038/nature23088
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