Monday, March 20, 2023

Leslie Reperant's "Fatal Jump"

Leslie Reperant is a doctor of veterinary medicine and earned a PhD in ecology and evolutionary biology from Princeton University. She has published her research on emerging infectious diseases in leading scientific journals, including The Lancet and Science.

Reperant applied the "Page 99 Test" to her new book, Fatal Jump: Tracking the Origins of Pandemics, and reported the following:
Page 99 of Fatal Jump is the closing page of Chapter 3 on heirloom and souvenir parasites and pathogens that have afflicted humans (and other hominins) since prehistory. It opens on a world map showing the prehistoric dispersion routes of Helicobacter pylori along the migration of humans within and out of Africa tens of thousands of years ago: a pandemic that spread at the rhythm of our hunting-gathering ancestors. This spiral-shaped bacteria inhabits the lining of the stomach of more than half of the human population today, and is associated with increased risk of developing gastritis, ulcers, and cancer. Its association with humans started long ago, upon a prehistoric host jump from a mysterious animal into humans. Because the species of Helicobacter acinonychis present in the stomach of large African felids, like lions and cheetahs, is closely related to humans’ Helicobacter pylori, researchers proposed that prehistoric hunters may have acquired the bacteria after savoring some large felid stomach. But thorough analyses of the genetic sequences of these two species of Helicobacter revealed, shockingly (or perhaps not much so), that the jump had occurred in the opposite direction: the ferocious large felids acquired the bacteria after devouring prehistoric human stomachs instead, about 45,000 years ago. The remainder of page 99 reads:
So long for lions as the source of our once-zoonotic Helicobacter: our prestigious shoulder rubbing had turned ugly. The next closest relative of Helicobacter pylori and Helicobacter acinonychis is Helicobacter cetorum, found in dolphins and whales. This leads to yet more perplexing interrogations on the still enigmatic origin of Helicobacter pylori in humans and of Helicobacter cetorum in cetaceans for that matter.

Retracing the prehistoric origins of heirloom and souvenir parasites and pathogens is fraught with uncertainties, and often uncovers unexpected—and sometimes unexplainable—developments along the paths of their long associations with hominins. And yet, with languages and pottery cultures, the phylogeography of heirloom parasites and pathogens retraces the remarkable prehistoric journey of modern humans across the Earth’s continents and illuminates the enduring relationships hominins have had with some of the agents of humans’ most entrenched chronic diseases.
Fatal Jump passes the Page 99 Test fairly well. The short story of the rise of Helicobacter pylori in humans is a neat example of an unexpected jump of a zoonotic pathogen from a so-far mysterious animal—yet probably hunted for food or other resources—to humans. It illustrates well the global spread of such new associations due to the (long) mobile propensity of humans. It showcases these associations’ far-reaching consequences on today’s human health. But the end paragraph also provides a clue on what is to come. It ends on a reflection about the enduring relationships humans have had with some of the agents of our most entrenched chronic diseases. The changes that propelled humanity from prehistory into history would soon allow for the rise and spread of the agents of more devastating, acute infectious diseases.

Fatal Jump is indeed a journey, by leaps and bounds around the world and through time, that leads the reader to examine the extraordinary circumstances—evolutionary, ecological, and otherwise—that converged and gave birth to some of our most wicked plagues and pandemics, including the latest one. This journey is full of (often unsettling) surprises. In the field of emerging infectious diseases, we know to expect the unexpected. Dear prospective reader, the question I have for you is: Are you ready to meet the unexpected?
Visit Leslie Reperant's website and follow her on Twitter.

--Marshal Zeringue