In 1969, Surgeon General William H. Stewart triumphantly stated that we could ‘close the book on infectious diseases. In the 1980s, pharmaceutical companies began to redirect investment away from antibiotic development, until a humbling reality began to cripple the medical community in the twentieth century. Antibiotic resistance was paving the way for old infectious diseases to re-emerge. Cohen discusses the troubling case of antibiotic resistance involving the bacteria, Strep. pneumoniae (DRSP), which causes pneumonia and death. Antibiotic resistance is not the only factor driving the re-emergence of virulent infectious diseases. Changes in society and technology are other culprits. Refrigeration to preserve food and kill food borne pathogens have naturally selected for the progress of cold-loving pathogens like Listeria or Yersinia which causes food poisoning and related symptoms. Additionally, at the start of the twentieth century US citizens aged 65 and older constituted less than 5% of the American population but by 2040 they will account for 25%. The dynamics of disease within an aging demographic present a new challenge to control transmission and treat illness in a vulnerable population. This reality hit home during the COVID19 pandemic. Infectious diseases continue to be an area of concern for the US and the world.
When infectious diseases emerge or re-emerge, minorities in the US have been seen to be disproportionately affected. This raises a conundrum: why do minority communities in a developed nation experience a higher rate of infectious disease? When describing the re-emergence of tuberculosis in US inner cities, the CDC posited that “tuberculosis retreated into geographically and demographically defined pockets.” 2 Garcia explains that this “retreat” was driven by social dynamics, specifically residential segregation.2 Residential segregation creates communities isolated by poverty and overcrowding where there is limited access to healthcare and poor implementation of social intervention strategies.2 Cohen describes another demographic of vulnerable individuals who, with increased lifespan, present new opportunities for infectious diseases to flourish. These are people who live with chronic diseases, like cancer, diabetes, and Hodgkin’s disease. During the COVID19 pandemic, members within this group were also more vulnerable. Infectious agents that previously were not widely seen are on the rise as well, including Legionnaire’s disease, toxic shock syndrome, Lyme disease, Nipah virus, hantavirus, Escherichia coli O157:H7, ‘flesh-eating’ bacteria, and many others.1
In 2006, King et al. posited eight categories of known infectious diseases that would require improved detection systems in the upcoming 10-25 years.3 His list included SARS, H5N1 and influenza variants, antibiotic-resistant infections like tuberculosis, zoonoses, acute respiratory diseases and sexually transmitted diseases; the COVID19 pandemic proved one of these predictions true. In 2020, Smiley-Evans et al. posited that a zoonotic pandemic could be the next potential threat.4 The potential for zoonotic infectious diseases is highly concerning for the US since it is, apart from China, the world’s largest exporter and importer of livestock and its derivatives.4 Since urbanization, changes in farming, and livestock proximity have increased the likelihood of cross species transmission between animals of different species and animals and humans, Smiley-Evans et al. argues that zoonotic diseases are the new major threat. For example, methicillin-resistant Staphylococcus aureus (MRSA) and antimicrobial-resistant Escherichia coli (plasmid-mediated colistin resistance mechanism, MCR-1) are on the rise in livestock like pigs and human beings. These gram-negative bacterial food pathogens are known to cause serious infections in human beings.4
More focus on disease ecology is needed to mitigate the threat of a zoonotic pandemic.4 With current trends, it is critical that resources be directed toward the prediction, prevention, and treatment of infectious diseases.
References
1. Cohen, M. Changing patterns of infectious disease. Nature 406, 762–767 (2000). https://doi.org/10.1038/35021206
2. Acevedo-Garcia D. Residential segregation and the epidemiology of infectious diseases. Soc Sci Med. 2000 Oct;51(8):1143-61. doi: 10.1016/s0277-9536(00)00016-2. PMID: 11037206.
3. King DA, Peckham C, Waage JK, Brownlie J, Woolhouse ME. Epidemiology. Infectious diseases: preparing for the future. Science. 2006 Sep 8;313(5792):1392-3. doi: 10.1126/science.1129134. PMID: 16959992.
4. Smiley Evans, T., Shi, Z., Boots, M. et al. Synergistic China–US Ecological Research is Essential for Global Emerging Infectious Disease Preparedness. EcoHealth 17, 160–173 (2020). https://doi.org/10.1007/s10393-020-01471-2