“How inscrutable and incomprehensible are the hidden works of Nature!”
Antonie van Leeuwenhoek, 17th Century Dutch microscopist, Father of Microbiology
“If my efforts have led to greater success than usual, this is due, I believe, to the fact that during my wanderings in the field of medicine, I have strayed onto paths where the gold was still lying by the wayside. It takes a little luck to be able to distinguish gold from dross, but that is all.”
Robert Koch, 19th Century German physician, Father of the Germ Theory of Diseases
I launched Germ Gems on July 20, 2019 as a vehicle to provide timely information on what’s new in the microbial world for a general audience. Today, I celebrate its fifth anniversary and highlight six topics (all subjects of past posts) that I believe are likely to remain top priorities in the field of infectious diseases.
Antimicrobial Resistance. Many experts agree that the biggest infectious diseases challenge globally is preventing the emergence of microbes that are resistant to antimicrobials. Solving this problem is complicated because of evolution—antibiotic pressure in the environment leads to selection of the fittest (antibiotic-resistant) microbes. As Louis Pasteur said: “It is the microbes who will have the last word.”
Many leaders in academia, the pharmaceutical industry, government, and non-profit organizations are working tirelessly to slow, if not stop, this crisis. Let’s hope they do and prove Pasteur wrong.
COVID-19. No one predicted that a novel coronavirus, SARS-CoV-2, would emerge and precipitate the COVID-19 pandemic. When the virus emerged Wuhan, China in December 2019, epidemiologists and scientists alike had the histories of literally hundreds of prior pandemics to draw upon as they developed strategies to combat SARS-CoV-2, the etiologic agent. But as professor Adam Kucharski, an epidemiologist at the London School of Hygiene and Tropical Medicine, said, “There is a saying in my field: ‘If you’ve seen one pandemic, you’ve seen…one pandemic.’ That is to say, they all play out in different ways.” The COVID-19 pandemic is a great case in point.
The initial response to COVID-19 was frenzied and missteps were certainly made. Nonetheless, in the first year of the pandemic, the first-ever effective mRNA vaccines were developed and rolled out—an astonishing achievement. In addition, two antiviral drugs for treating COVID-19 were available by the end of 2021 (Remdesivir, December 2020; Paxlovid, December 2021).
Despite these remarkable accomplishments, by April 2023 in the U.S. the number of cases of COVID-19 exceeded 104 million with over 1.1 million deaths. New variants—most recently those dubbed FLiRT variants—continue to emerge requiring additional boosters to prevent infection. Then there is the associated pandemic of Long COVID for which there’s no effective treatment. (According to the Centers for Disease Control and Prevention (CDC), as of April 2024 an estimated 5.3% of all adults in the U.S. reported having Long COVID.) We have won many battles against SARS-CoV-2, but the war is far from over.
Influenza Viruses. The 1918-1919 “Spanish” influenza pandemic is sometimes referred to as “The Mother of All Pandemics” because it caused about 50 million deaths worldwide. (A total of 675,000 Americans died from the “Spanish” flu.) Since then, several additional smaller pandemics of influenza A virus erupted, and seasonal flu outbreaks of influenza A are now routine.
But another influenza A strain, H5N1(avian flu), is now on the rampage and keeping many epidemiologists and public health officials awake at night. At present, this influenza virus is taking its toll predominantly on birds, both wild and domesticated. But many mammals other than humans have been caught in its crosshairs—dairy cows being the most recent. As I embark on the sixth year of writing Germ Gems, the $64,000 question is: Will H5N1 acquire the ability to pass easily between humans and trigger the next catastrophic pandemic?
Vaccines. The development of vaccines is by far the single most important public health accomplishment ever. According to the CDC, “about 4 million deaths worldwide are prevented by childhood vaccination every year,” and “more than 50 million deaths can be prevented through immunization between 2021 and 2030.”
As of 2023, there were effective vaccines against 33 human diseases. And vaccines against Mycobacterium tuberculosis, the cause of TB, and HIV, the etiology of AIDS, are leading targets for future vaccine development. But of the roughly 1,400 microbial species that cause disease in humans, only one pathogen, variola virus (the cause of smallpox), has been eradicated due to a heroic vaccine campaign that lasted almost two centuries. Eradication of the remaining 1,399 species isn’t a realistic goal, but there is a good shot that some (for example, polio virus and measles virus) could be, and many other pathogens can be kept in check by routine vaccinations.
Climate Change. Climate change is not a hoax; it is the single biggest threat to human health. As I discussed in a number of prior posts, global warming fosters the reproduction and geographic spread of mosquitoes and ticks, the vectors of many pathogens. Clever new strategies aimed at these insect vectors are showing promise.
Dealing effectively with global warming requires extraordinary commitments on the part of the responsible industries and governments. Only time will tell if sufficient commitments are there. Unfortunately, time is running out.
Human Microbiome. In terms of discoveries, none was more astonishing to me than the recognition of the role of the human microbiome (defined as the microbes that share our body surfaces) in health and disease. Due to the pioneering work of Carl Woese in the 1970s, the nature of the Tree of Life was redrawn, and a large number of scientists flocked to the exciting field of microbiome science.
Among the large number of these ecosystems, the gut microbiome has captured the most attention in the field of human medicine. I’ve admired and found humbling the brilliance and courage of the researchers working on the gut microbiome. Imagine trying to make sense out of an ecosystem composed of an estimated 100 trillion bacteria, a quadrillion viruses, and innumerable fungi and protists. I look forward to learning more about this fascinating aspect of medicine.
In the meantime, there already is mounting evidence that suggests that the gut microbiome plays a critical role in shaping emotions such as happiness. And we know that the communication between the gut microbiome and the brain is bidirectional. So, I am going to end this 265th post and celebrate Germ Gems’ anniversary by having a piece of cake and hoping the germs in my gut microbiome return the favor!
Congratulations and keep up the good work. Thank you!
Bill Conroy
Thank you Phil for your excellent written lectures. Very instructive!
Thank you for your continued insights, Dr. Peterson!
Bradley Smegal