The following is an edited transcript of infectious agents seminar against human health, October, 2019:
Moderator: Thank you for taking the time out from afflicting disease to attend this seminar and welcome our latest pathogen in training, SARS-CoV-2. Viral agents and Rickettsia should take the first few rows that contain cell cultures. It is my pleasure to introduce our guest speaker, inflicting misery on Homo sapiens for centuries, our President, Yersinia pestis.
Yersinia pestis: Thank you. For those of you who are unfamiliar with my resumé, I am responsible for bubonic, pneumonic and septic plague. Partnering with the black rat and rat flea, I have inflicted death rates of 50-80% for generations. I helped take down the Roman Empire in the 6th century by killing thousands of farmers. Since the farmers were now not available to pay their Roman taxes to support the military, this led to the collapse of the Roman armies. My greatest hit was 1346-1353 where I took out half of the population of Europe. I started out in China, traveled with traders overland and with the shipping trade and went west, south and northwest, tightening the noose of misery on millions. I took on one of the greatest city-states at the time, Florence, and annihilated hundreds of thousands. For those Florentines that had a false sense of security and fled to the countryside, my coterie of fleas and bacilli followed them and finished them off. I rushed into Avignon, then the seat of the papacy, and inflicted so much suffering that the Pope blessed the Rhône River as a burial site. As the centuries passed and I lost some of my virulence, I came back every few generations of humans to remind them of my sordid deeds.
Of course, I couldn’t do it alone so I’d like to introduce my fellow “partners in crime.”
Bacillus anthracis: Thank you, Yersinia. Some may say I take a backseat to the Plague but others recognize me as a formidable foe. I cause Anthrax. I received some kudos from human terrorists who used my spores to infect others through the U.S. mail in 2001. I am crafty and can infect humans through the skin, lungs and gut. Proudly, I can kill 85% of victims within hours or days. What about those deaths in England in 1348-1349? Yes, I chipped in with Yersinia by killing cattle, transmitting my disease through eating meat and leaving my spores in burial graves. My spores can stay viable in soil for over 40 years! Now, THAT is staying power.
Moderator: We acknowledge the lesser known genera, Rickettsia and their contribution to human suffering.
Rickettsia prowazekii: I’ll be brief as I cannot stay long outside my cell culture medium. I may be intracellular but even humans acknowledge my clout: my disease is called EPIDEMIC typhus. My ride is the human louse, pediculus humanus corporis. I thrive with poverty, war and overcrowding and feel at home in endothelium, the cell that lines blood vessels. I cause rash, headache, cough, muscle pain and then progress to shock and delirium and then death. I have caused more deaths than all the wars combined. I was there during the Peloponnesian War in ancient Greece, the Thirty Years’ War and the Napoleonic Wars. In fact, I killed more of Napoleon’s troops than did the Russians. I caused misery and death during the Great Irish Potato Famine in 1846 and spread to England. The English called it the “Irish fever,” blaming the Irish instead of giving me full credit for the disease. While poverty and hygiene has improved recently and the human louse is in short supply, I jumped to the flying squirrel to cause intermittent disease in modern humans. Please be assured, I am still in the game and doing my part.
Moderator: My thanks to all of the innovative microbes that have stricken so many for so many centuries. Now, we welcome our latest entry to the world of human virulence, an RNA virus from an unheralded family. Let’s give a warm welcome and a round of applause for SARS-CoV-2.
SARS-CoV-2: I am humbled to take my place among the greats of infectious disease. I want to express my gratitude to our “think tank” and mammalian assistant, the bat, who has unselfishly provided incubation over the centuries to improve our infectivity. I proudly come from the family of Coronaviruses. We have been in the human disease business for over 800 years, but have been underwhelming as we have only succeeded in causing the common cold with our first 4 family members. We showed promise in 2003 with the release of my brother, SARS-1, and a later cousin, MERS. SARS-1 had an encouraging mortality of 50% and we were packing the ICU’s in Asia. We did not plan for high transmission rates and with public health measures we were stymied early in the game. I inherited 85% of the genome and fine tuned my transmission rates. In contrast to my ancestor SARS-1, who was most infectious during severe illness, I made sure I could jump to another human even before they were experiencing my infective presence. This was the magic bullet for my success and I am honored to be nominated for rookie pathogen of the year.
Yersinia pestis: I want to thank all in participating in this important update. Let me remind you that Homo sapiens are adaptable and we must be vigilant. In Florence, after several generations of plague, they formed isolation hospitals, board of health administrators and invoked quarantining measures to restrict my spread. They finally got the tools to see some of us in 1683 (early microscope, van Leeuwenhoek). Our fellow microbes have been betraying us starting in the 20th century with penicillin (the mold Penicillium notatum), streptomycin (the bacteria Streptomyces griseus), and tetracycline (Streptomyces aureofaciens). Our machinery has been co-opted (DNA polymerase) and our bacterial tools to prevent viral infections in us have been discovered (CRISPR technology). We can take solace in that humans have short memories and often make irrational choices and blame others that have nothing to do with their plight. But we must stay vigilant: It is never too late to mutate! Let me call this meeting adjourned and we all look forward to next year’s gathering.