Credit UK HAIRS
#17,217
Although it is difficult to imagine given the large number of EID (Emerging Infectious Disease) outbreaks we've already seen over the past 20 years (see map above), but 18 months ago in PNAS Research: Intensity and Frequency of Extreme Novel Epidemics, researchers suggested that the probability of novel disease outbreaks will likely grow three-fold in the next few decades.
Most of these EIDs originated from a zoonotic source, with bats, birds, swine, rodents, mosquitoes, and ticks all major contributors. Sometimes these diseases jump directly to humans, and other times they are first transmitted to intermediate hosts.
Zoonotic Disease Pathways
The list of zoonotic diseases is long and continues to expand, and includes such well known infections as SARS, MERS, SARS-CoV-2, Babesiosis, Borrelia (Lyme), Nipah, Hendra, Malaria, Dengue, Zika, Hantavirus, Monkeypox, Ebola, Bartonella, Leptospirosis, Q-Fever, multiple flavors of avian flu and many, many others.
In 2014, in Emerging zoonotic viral diseases L.-F. Wang (1, 2) * & G. Crameri wrote:
The last 30 years have seen a rise in emerging infectious diseases in humans and of these over 70% are zoonotic (2, 3). Zoonotic infections are not new. They have always featured among the wide range of human diseases and most, e.g. anthrax, tuberculosis, plague, yellow fever and influenza, have come from domestic animals, poultry and livestock. However, with changes in the environment, human behaviour and habitat, increasingly these infections are emerging from wildlife species.
We explored some of the reasons behind this dramatic shift more than a decade ago in The Third Epidemiological Transition - which focused on the work of anthropologist and researcher George Armelagos (May 22, 1936 - May 15, 2014) - of Emory University.
Emerging infectious diseases are considered such an important public health threat that the CDC maintains as special division – NCEZID (National Center for Emerging and Zoonotic Infectious Diseases) – to deal with them, and 28 years ago the CDC established the EID Journal dedicated to research on emerging infectious diseases.
Fifty years ago, when I first began my career as an EMT, infectious diseases here in the United States were such a low concern that we routinely worked bare-handed. The only gloves we carried on our ambulance were in the sterilized OB kit, and if you broke into that, you'd better be delivering a baby.
Between better vaccines, a growing array of antibiotics - and even a few antivirals - infectious diseases were widely viewed as on the way out, making the conquering of chronic diseases (cancer, diabetes, heart disease, etc.) and the improved treatment of trauma viewed as the future of medicine.
In many ways, 1976 may have been the turning point.
Three major - and quite unexpected - EID outbreaks occurred that would shake the world; the Swine Flu scare, the Legionnaire's outbreak in Philadelphia, and 2 outbreaks of an unknown, and deadly, hemorrhagic fever (Ebola) in central Africa.
The swine flu scare of 1976 began in January, when a young recruit at Ft. Dix, New Jersey fell ill and died within 24 hours. Tests revealed he had a novel strain of influenza, previously unseen, dubbed `Swine Flu’. It was an H1N1, a strain that had disappeared `from the wild’ after the 1957 Asian Flu pandemic.
The alarm went out, and while no other deaths occurred at Fort Dix, many of the other soldiers tested positive for the virus. Most were without symptoms, but a few fell ill and recovered.Two weeks later, after consultation at the highest levels, the public was informed of the threat. The decision was made to create a vaccine, and inoculate the country. Things did not go as planned, but you can read the full story in Deja Flu, All Over Again.
Within days of returning home from the convention, more than 180 people would fall ill with (often) severe flu-like symptoms, and at least 29 died. Notified by a doctor who saw multiple patients fall ill after attending the convention, the CDC launched an investigation.
For several days, we thought this might be the first outbreak of swine flu, but pandemic influenza was ruled out fairly quickly.
Four months later a CDC lab would identify the culprit as an aquatic gram-negative bacterium - subsequently dubbed Legionella pneumophila - which could cause mild to severe pneumonia.
Legionella wasn't new of course, just finally isolated and identified. Its discovery led to retrospective identification of previous outbreaks, including an earlier outbreak at the same Philadelphia hotel (see The Lancet 1974 outbreak of Legionnaires' Disease diagnosed in 1977).
Lastly, over September and October 1976, 318 cases of acute viral hemorrhagic fever occurred in northern Zaire, resulting in 280 deaths (see WHO Bulletin Ebola haemorrhagic fever in Zaire, 1976), which would eventually be identified as Zaire ebolavirus.
Suddenly, emerging infectious diseases were back on display, and while the swine flu pandemic of 1976 fizzled, H1N1 did return the following year after an absence of 2 decades, sparking a pseudo-pandemic among those born after 1957.
While the exact mechanism of that virus’ return still isn’t known, the strain was so similar to one last seen in the 1950s that it has been postulated that it was the result of an accidental lab release in China or Russia (see PLoS ONe The Re-Emergence of H1N1 Influenza Virus in 1977 . . . ). Hence, it was dubbed the `Russian Flu’.
Since then, new - mostly zoonotic - infectious diseases have continued to emerge. The spread of HIV in the early 1980s reinforced the lessons of 1976, and reminded us that modern medicine still had limits. Since then, the frequency of spillover events into humans has only increased.
This past week the UK HAIRS ( Human Animal Infections and Risk Surveillance group) published an overview of two decades of major EID spillovers into humans. Included are a map (see above), a timeline, and a table showing newly identified emerging infections and notable outbreaks of diseases in humans in new areas between 2003 and 2022.
By all means, follow the link to read the full report, as I've only reproduced the timeline below the link. As busy as this graphic is, if the aforementioned PloS study from 2021 is anywhere near correct, the next 20 years will be even more so.
5 January 2023
If `What's past is prologue', then we should really take a hard look at this graphic, and start treating pandemic preparedness and public health as crucial and integral parts of our national security.
Not something to be discussed ad nauseam, but ultimately left to wither unfunded, or under staffed, until the next crisis emerges.
I'm not optimistic, as we seem to immediately forget the lessons of every public health crisis as soon as the `all clear' is sounded.
No matter how many times nature reminds us.
