Zoonosis book to read

Spillover: Animal Infections and the Next Human Pandemic, by David Quammen (2012): another excellent nonfiction published in the decade before the COVID pandemic, and which should have been an eye-opener to governments. (Others in this category are Pandemic: Tracking Contagions, from Cholera to Ebola and Beyond, by Sonia Shah [2016] and Epidemics and Society: From the Black Death to the Present, by Frank M. Snowden III [2019].)

 

First off, Quammen is an excellent writer. His writing reads like lyrical prose even when the subject matter is deadly. He writes for National Geographic and has published a number of science books, especially looking at evolution and ecology. Particular quotes I love are:

“Pondering [zoonoses] tends to reaffirm the old Darwinian truth (the darkest of his truths, well known and persistently forgotten) that humanity is a kind of animal, inextricably connected with other animals: in origin and in descent, in sickness and in health.”

“Infectious disease is a kind of natural mortar binding one creature to another, one species to another, within the elaborate biophysical edifices we call ecosystems.”

“Every spillover is like a sweepstakes ticket, bought by the pathogen, for the prize of a new and more grandiose existence.”

 

Quammen is talented at explaining complex science understandably, as in this analogy of the structure of the influenza virus: “a single-stranded RNA genome, which is partitioned into eight segments, which serve as templates for eleven different proteins. In other words, they have eight discrete stretches of RNA coding, linked together like eight railroad cars, with eleven different deliverable cargoes.” Reassortment happens because “the segmentation allows their RNA to snap apart neatly at the points of demarcation between genes: those eight railroad cars in a switching yard.”

 

The book looks at various zoonoses (infections that can spread from animals to humans), which includes most of the nasty diseases you’ve heard of (rabies, Black Plague, COVID, Ebola, avian and swine flu, HIV, West Nile) and plenty of other nasties you might not have heard of (Nipah, Hendra, Marburg). Basically the only major pandemic-level infections (and bioterrorism threats) that aren’t zoonotic are smallpox and polio. Incidentally, smallpox and polio are the only diseases we’ve been able to eradicate, and that is specifically because they infect humans only, with no animal reservoir.

 

Zoonoses are pathogens that happily circulate in a reservoir host, not causing much illness or death, just replicating and spreading. The problem comes when that pathogen makes a jump to another species. If the pathogen evolves to spread within the new species, you’ve got a new infection. As an example, Nipah virus was traced to a certain fruit bat. The virus and the bat get along fine, happily living and reproducing together. The problem is when the bat drools on fruit or tree sap and then that bat saliva gets into a pig or a human. Pigs and humans experience severe symptoms and death, and can spread it to others of their species, leading to epidemic/epizootic potential.

 

Diseases that are covered in detail in the book are Hendra, Ebola, malaria, SARS, Q fever, Lyme, herpes B, Nipah, Marburg, HIV, and influenza. Along the way we meet interesting people like biologist Mike Fay walking 2,000 miles across central Africa on a Megatransect to identify every species encountered; Mr. Wei, a Chinese gentleman farming giant bamboo rats for food; scientists Lisa and Gregory Engel trapping monkeys at a Bangladeshi shrine; veterinarian Jon Epstein swabbing bats; Michelle Barnes, a tourist who survived an unrecognized Marburg infection from a bat cave; and a nameless seller in a food market, offering tasty smoked monkeys for 6,000 francs.

 

As a veterinarian and public health nerd, I especially found the section on malaria fascinating. Generally speaking, malaria is considered a human infection: the malaria parasite is spread from one person’s bloodstream to another person’s bloodstream via mosquito bites. But as Quammen points out, “everything comes from somewhere.” Malaria may be a human infection now, spread human-to-human, but where did it come from initially? Turns out, it came from animals. There are four major malaria strains and DNA research has found they actually came from four different animal spillovers. A fifth malaria strain may be in the process of currently evolving from animals to humans. As he writes, “The distinction between zoonotic diseases and nonzoonotic diseases is slightly artificial, involving a dimension of time. By a strict definition, zoonotic pathogens are those that presently and repeatedly pass between humans and other animals, whereas the other group of infections are caused by pathogens descended from forms that must have made the leap to human ancestors sometimes in the past.”

 

Another interesting section traces the evolution of HIV (human immunodeficiency virus) from SIVcpz (the specific strain of simian immunodeficiency virus in chimpanzees). Long story short: a human in southeastern Cameroon, probably a hunter cutting up a carcass, got SIV virus into his bloodstream from a chimpanzee, around the year 1908. Over the next couple decades, SIV circulated quietly in the local human population, causing just barely enough new infections to keep the virus going, slowly evolving to HIV, slowly traveling to what was then Leopoldville in the Belgian Congo and is now Kinshasa in the Democratic Republic of Congo. It started to spread much more rapidly in the 1930’s-50’s via well-meaning but inadvertent blood-to-blood contact in the form of reused needles/syringes in medical clinics treating trypanosomiasis and syphilis. In 1960, Belgian colonizers were kicked out of the Congo and Haitians filled a labor shortage, then one of those Haitians returned home carrying HIV. In Haiti, HIV spread through the 1960’s-70’s, again by inadvertent blood-to-blood contact in a medical setting, that of plasma donations. HIV traveled from Haiti to Miami, either in a human or in a plasma bag, around 1969 and then onward around the globe.

 

The final chapter is called It Depends, referring to the Next Big One. Of course, we’re in the Next Big One now, and some of this chapter is prescient. Quoting epidemiologist Donald Burke in 1997 (pre-SARS): “’Some of these viruses,’ he warned, citing coronaviruses in particular, ‘should be considered as serious threats to human health.’” And quoting mathematical ecologist Greg Dwyer: “’Any tiny little thing that people do,’ Dwyer said, if it makes them different from one another, from the idealized standard of herd behavior, ‘is going to reduce infection rates.’” Quammen writes, “An individual human may choose not to drink the palm sap, not to eat the chimpanzee, not to pen the pig beneath the mango trees, not to clear the horse’s windpipe with his bare hand, not to have unprotected sex with a prostitute, not to share the needle in a shooting gallery, not to cough without covering her mouth, not to board a plane while feeling ill, or not to coop his chickens with his ducks.” I would add to that: a human may choose to socially distance, to wear a mask, and to get vaccinated. Please do.

Still in a pandemic but more time for reading...

This past year I read five nonfiction books about pandemics in general and COVID-19 in particular. All are excellent, and approach the issue from different directions. Two are pre-covid, and three are post-covid.

(As an aside, after 9/11, pundits exclaimed, “No one ever imagined an airplane could be used as a terrorist weapon!” Yes, they did. Tom Clancy’s novel, Debt of Honor (1998) ends with a terrorist piloting an airplane into a joint session of Congress, killing nearly everyone in government except for the designated survivor. Similarly, as covid circled the globe, pundits said, “No one expected a pandemic!” Yes, they did. Two of these books were published shortly before the pandemic, along with recent pandemic novels including Chuck Wendig’s Wanderers and Lawrence Wright’s The End of October. People just weren’t paying attention.)

In order of publication:

Pandemic: Tracking Contagions, from Cholera to Ebola and Beyond, by Sonia Shah (2016).

Shah focuses on how pandemics arise: what factors, both biological and sociological, mean some outbreaks turn into a pandemic while others fade away? She uses the historical cholera (Vibrio cholerae) outbreaks of the 19th century to illustrate concepts that allow a pandemic to start and flourish: a jump from animals to humans, transportation around the globe, filth and crowding, governmental corruption and greed, and scapegoating. These factors show up over and over in pandemics. The vast majority of emerging infectious diseases are zoonotic, spread from animals to humans; air travel means that a virus can spread worldwide in a day; governments might try to cover up an outbreak or seize the opportunity to get rich selling treatments (legitimate or not); and people will blame the epidemic on scapegoats (Jews with plague, gay men with AIDS, doctors with covid). 

Epidemics and Society: From the Black Death to the Present, by Frank M. Snowden III (2019).

Snowden looks at how epidemics affect society, inspire public health innovations, and even change the course of history. For example, when smallpox was introduced to indigenous populations in the Americas, it wiped out entire populations. The indigenous population of Hispaniola fell from 1 million to 15 thousand after Columbus, easily enabling colonization. So many indigenous people died in the Americas that colonists needed to import labor from elsewhere—leading directly to the African slave trade and Middle Passage. Another example: in the War of 1812, a third of Napoleon’s army died of dysentery (Shigella) on the march to Moscow, and then most of the rest died of typhus (Rickettsia) on the march back to France.

The Plague Year: America in the Time of COVID, by Lawrence Wright (June 2021).

Although covid has of course been a global pandemic, Wright focuses on just the experience in the United States during the first year of the pandemic. 2020 was the deadliest year ever in US history. The United States has just 4% of the global population but 20% of covid deaths. Why? There were three factors working against us: 1. China obscured knowledge of the disease in the beginning and denied entrance to US epidemiologists; 2. CDC tests were faulty (with a contaminated component); 3. The former president spouted crazy anti-science messaging. Wright interviews experts including Anthony Fauci; Robert Redfield (CDC); Deborah Birx, who was more courageous than she appeared in press conferences, and embarked on a cross-country road trip to educate state and municipal leaders; Barney Graham and Jason McLellan, the researchers who were already working on an mRNA vaccine against the spike protein of previous coronaviruses, MERS and SARS; historian of medicine Howard Markel and CDC’s Martin Cetron, who investigated the 1918 influenza outbreak to learn what worked and what didn’t; and politicians of both parties. Wright also looks at how the pandemic became irrevocably tied in with politics of 2020-21, including Black Lives Matter/systemic racism and Stop the Steal/conspiracies. A right-wing conspiracy to abduct Governor Gretchen Whitmer of Michigan because of her statewide mask mandate was prompted by the former president, who tweeted “LIBERATE MICHIGAN.” That essentially turned into a dress rehearsal for the January 6 insurrection. Wright concludes that two qualities determined success or failure for a country facing covid: 1. experience (southeast Asia had dealt with SARS, Saudi Arabia had dealt with MERS, and Africa had dealt with AIDS), and 2. leadership or lack thereof.

Until Proven Safe: The History and Future of Quarantine, by Geoff Manaugh and Nicola Twilley (July 2021).

Fascinating look at the history, politics, infrastructure, and ramifications of quarantine over the last 600 years and into the future. Includes visits to plague-era lazarettos in Dubrovnik, Venice, and Malta; the National Quarantine Unit in Omaha, which hosted some of the earliest COVID patients but only has room for 20 patients; the under-construction National Bio and Agro-Defense Facility in Kansas, which will allow research on horrible livestock pathogens like foot-and-mouth disease; the International Cocoa Quarantine Center outside London (cacao plants are one of the few plants that are so valuable that they are worthy of a three-year quarantine); the Cereal Disease Laboratory (investigating wheat pathogens that could wipe out the entire US economy, located in Minnesota and only operating in winter to prevent accidental escapes from the lab); the Waste Isolation Pilot Plant in New Mexico, where radioactive materials are to be quarantined for 10,000 years (and addressing the question of "How do you warn people in the year 8,022 not to drill in this site?"); and the Johnson Space Center in Houston, keeping our planet safe from lunar or martian pathogens and keeping the moon and Mars safe from earthly pathogens.

World War C: Lessons from the Covid-19 Pandemic and How to Prepare for the Next One, by Sanjay Gupta (October 2021).

Unlike many celebrity doctors, Dr. Gupta is actually a smart guy and trustworthy. Gupta looks at where we are with respect to covid over the last 18 months. He conducted hours of interviews with scientists, doctors, and politicians. He covers the timeline of the pandemic, the science of viruses, the technology of vaccines, and talks of preparation for the next pandemic. Yes, there will be another pandemic, and it will be sooner than next century.

Proboscideans are Cool

I turned 50 last week and for my birthday I wanted to go to natural history museums. I’m a museum nerd, a paleontology nerd, and the Pleistocene is my favorite time period, so I planned a trip to the Los Angeles area. I told my family that they could come but they had to be willing to be dragged to museums and weren’t allowed to complain about it. So I planned a four-day weekend and we saw four museums (plus an aquarium). The museums were the La Brea Tar Pits/George C. Page Museum, the Western Science Center, the San Bernardino County Museum, and the Natural History Museum of Los Angeles County. More on the museums themselves later.

California is a pretty awesome place for paleontology. The state mandates that any paleontological artifacts encountered during construction be reported and dug up by a salvage paleontologist. With all the construction that happens in that state, this means a lot of specimens for science. The finds in the LA area are Pleistocene, so that means lots of megafauna for museums.

I love proboscideans—the elephant family (proboscis = nose). There are a lot of extinct elephant species, besides the two extant species, including four-tuskers, shovel-tuskers, and straight-tuskers. The proboscideans we met in LA were:

At La Brea:

American mastodon (Mammut americanum)

Columbian mammoth (Mammuthus columbi)

Comparison of lower jaws (mandibles) of Columbian mammoth and pygmy mammoth

Pygmy mammoth (Mammuthus exilis) – “exilis” because they were exiled onto small islands off the Californian coast. Island populations are weird because big animals tend to evolve smaller (because of limited resources) while small animals tend to evolve big (because of lack of predators). These wee little mammoths lived on Santa Rosa, San Miguel and Santa Cruz islands up to 10,000 years ago.

You could keep a pygmy mammoth as a backyard pet!

At Western Science Center:

Pacific mastodon (Mammut pacificus) – this holotype of a new species is nicknamed “Max.” The Pacific mastodons are larger than the American mastodons, and none have tusks in the lower jaw (many American mastodons do).

Columbian mammoth (Mammuthus columbi) “Xena”

"Xena" in front, "Max" behind

I really like how Western Science Center presents its fossils. One of the complaints you hear from science deniers is that “dinosaur bones are all replicas,” implying that they are fake, just made-up fantasies like Godzilla. Yes, most (but not all) mounted skeletons are replica casts; the fiberglass casts are much sturdier and much lighter weight, and leave the actual bone free for study. At Western Science Center, the mastodon and mammoth are mounted with a metal silhouette and casts of the bones put in the anatomical location, and then in the base of the mount under glass are the actual bones themselves, nestled in sand to support the fragile bones. You can see the real bones, with the real glue that preparators used. Max’s pelvis is too fragile to cast, so only the real bones are present under the mount.

Max's femur. You can see the preparation glue.

Max's left ribs

Xena on the left and Max on the right. The mounted skulls and bones are casts, and the original bones are in the glass-topped recesses in the base of the mount, with the skulls in separate glass cases.

Xena's fibula and femur

Max's pelvis, which is too fragile to cast so the mount doesn't have a pelvis.

At San Bernardino County Museum:

American mastodon (Mammut americanum) – they weren’t actually fluffy but it’s so cute! A fluffy dire wolf threatens the fluffy mastodon from the second floor.

At the Natural History Museum of LA County:

American mastodon (Mammut americanum)

Here we are, still in a pandemic...

Epidemics and Society: From the Black Death to the Present, by Frank M. Snowden

 

Super interesting book by a historian of medicine at Yale. Recommended in general to anyone interested in history, large-scale societal changes, medicine, or infectious diseases, and also recommended to anyone frustrated with COVID-19 responses over the last 18 months and looking for context.

 

The book is copyright 2019, and includes an additional preface from 2020 addressing COVID-19. I write this in the second half of 2021 as our nation experiences the fourth wave of COVID. From the preface: “Like all pandemics, COVID-19 is not an accidental or random event. Epidemics afflict societies through the specific vulnerabilities people have created by their relationships with the environment, other species, and each other. Microbes that ignite pandemics are those whose evolution has adapted them to fill the ecological niches that we have prepared.” In the case of COVID, we—humanity—created the epidemic because of habitat destruction, increased contact with wildlife, rapid international travel, and underfunding of public health infrastructure. “Nobel laureate Joshua Lederberg famously argued that, in the contest between humans and microbes, the only defense humans possess is their wits. One could add to Lederberg’s formulation our capacity to collaborate—if we so choose.” Alas, many people in our world and our country lack both wits and the willingness to collaborate.

 

Dr. Snowden looks at major epidemics over the last millennia, when/where/why they occurred and how they resolved, and explores how society responds to them—both formalized and informal responses, including public health developments, riots, scapegoating, inspiration for arts and literature, the sanitary movement, etc. Infectious diseases have changed wars and the course of history. He also summarizes the advancements of medicine from the supernatural causes (divine theory: illness is a punishment sent by an angry god; demonic theory: demons cause illness through their evil influence) to humoral theory (disease occurs because of an imbalance of the four humors within your body) to the Paris School of Medicine (hospital-based learning for physicians and students, with physical exams correlated with autopsy findings) to germ theory (infectious diseases are caused by microbes, not “miasma” or bad air).

 

Epidemics covered:

 

Bubonic plague (Yersinia). There have been three major epidemics, the Plague of Justinian (5^th-7^th centuries), the Black Death (13^th-15^th centuries), and modern plague (1870’s to present). Black Death significantly impacted total population numbers for centuries, economy, religion, art, and development of public health measures. Societal responses in particular to the Black Death included flight (rapidly evacuating from places with outbreaks, thus spreading infection), scapegoating (blaming the plague on Jews and prostitutes), and religiosity (Saint Sebastian and Saint Roch were worshipped as plague saints). The plague also prompted the first institutional public health measures: “The first antiplague measure was the establishment of an institutional framework of officials capable of taking extraordinary action to defend the community throughout an emergency. Created under specially drafted ‘plague regulations,’ the new authorities were termed ‘health magistrates.’ They exercised full legislative, judicial, and executive powers in all matters relating to public health under the ancient precept salus populi suprema lex esto (the health of the people is the highest law).” Modern plague exists still today, maintained in wild rodent populations and causing regular outbreaks. 

 

Smallpox. Smallpox killed approximately half a million Europeans every year throughout the 18^th century. Smallpox was endemic, considered “normal,” so did not induce hysteria, riots, and scapegoating as plague did. When smallpox was introduced to indigenous populations in the Americas, it wiped out entire populations. The indigenous population of Hispaniola fell from 1 million to 15 thousand after Columbus, easily enabling colonization. So many indigenous people died that it prompted importing labor from elsewhere: “disease was an important contributing factor in the development of slavery in the Americas and the establishment of the infamous Middle Passage.” In the formal public health realm, smallpox led to the invention of vaccination—and, alas, the first antivaxxers (“the antivaccination movement in both Europe and the United States became one of the largest popular movements of the 19^th century”).

 

Cholera (Vibrio). The first cholera epidemic was in 1817, and was followed by six more pandemics. The cholera organism relies on human movement, and it wasn’t able to establish pandemics until the modern era of global travel. “Cholera thrived on such features of early industrial development as chaotic and unplanned urbanization, rapid demographic growth, crowded slums with inadequate and insecure water supplies, substandard housing, an inadequate diet, ubiquitous filth, and the absence of sewers.”

 

Tuberculosis (Mycobacterium). TB is interesting because its epidemic lasted across the time of the discovery of germ theory; before germ theory, it was thought to be an inherent illness that increased a person’s intelligence, beauty, and creativity (Keats), but after germ theory it was seen to be contagious and evil, and patients were shunned.

 

Malaria (Plasmodium). Malaria continues to be a major problem today, with half a million deaths per year despite good prevention and treatment options.

 

Poliomyelitis. Polio was historically a cause of infant mortality, but with improved sanitation around the early 20^thcentury, people reached adulthood without having been exposed, and new epidemics were seen in affluent teens and adults. After widespread vaccination in developed countries, the epidemic shifted to the impoverished, ethnic minorities, and religious groups that opposed vaccination.

 

HIV/AIDS. Snowden compares the epidemic in South Africa (a disease of the general population spread by heterosexual sex and worsened by the legacy of apartheid) to the epidemic in the US (a focal disease of white gay men spread by homosexual sex and leading to stigmatization). In both cases, disinformation played a significant role in spreading disease.

 

Emerging and reemerging diseases. Ebola, dengue, cholera, antibiotic-resistant bacteria, and SARS all demonstrate the global lack of preparedness to deal with epidemics—as we’ve seen with COVID. “To survive the challenge of epidemic disease, humanity must adopt an internationalist perspective that acknowledges our inescapable interconnectedness.”

 

Societal effects of epidemics discussed:

 

Scapegoating (blaming a group of people for the disease) and conspiracy theories:

• ·      Black Death was blamed on Jews, prostitutes, foreigners, witches, lepers, beggars—people were stoned, lynched, and burned at the stake.
• ·      Cholera’s symptoms progress very rapidly, causing explosive diarrhea and death within hours, which led people to believe it was a poison rather than an infection. People in the slums noted that health officials, clergy, and doctors didn’t fall ill when they came into the slums (because they weren’t eating and drinking and sleeping there) and thought they were deliberately introducing the disease. This led to riots in hospitals to “rescue” patients, and attacks against doctors and stretcher-bearers.
• ·      During an outbreak of plague in 1894 in Hong Kong, there were “desperate rumors that the colonial government of ‘foreign devils’ was spreading plague as a means to rid itself of the poor while harvesting their body parts for experimentation and allowing ‘barbarian’ soldiers to take women away to satisfy their ‘sordid intentions.’” In Bombay (Mumbai) in 1896, a rumor told that plague “was a poison administered by the British to solve the twin problems of overpopulation and poverty. A further theory alleged that Queen Victoria’s intention was to sacrifice Indian bodies to placate the god of plague, thereby preserving Britain, not India, from divine wrath.”
• ·      The global attempt to eradicate polio has run into some problems in the 21^st century. “In Kano [Nigeria], Muslim leaders, suspicious of Western intentions after the launching of war in Afghanistan and Iraq, preached that Sabin’s doses were not a public health measure at all. The vaccine, they warned, formed part of a sinister plot to sterilize Muslim children with a reproductive poison.”

 

Formal public health developments:

• ·      Plague: Venice invented quarantine (quaranta = forty), where incoming ships and their cargo, crew, and passengers, were isolated for 40 days and decontaminated. Austria maintained an overland sanitary cordon, a permanent line of troops and forts that protected much of Europe for over a century.
• ·      Smallpox: Dr. Edward Jenner’s cowpox-derived vaccine, which eventually enabled eradication of smallpox, and which also led to other vaccine development including rabies and polio.
• ·      Cholera: city planning, sanitation, and public waterworks.
• ·      Tuberculosis: many formal sanitaria were established, where patients lived for months in a healthful environment, along with local community “dispensaries,” which offered free diagnostics and treatments and education of family members.
• ·      Malaria: efforts in Sardinia showed that multi-faceted prevention is key, with medications and mosquito-spraying being ineffective without also reversing environmental degradation, educating people, increasing the standard of living, and improving nutrition.
• ·      Polio: two vaccines were developed, Salk’s inactivated injectable vaccine in 1955, and Sabin’s modified live oral vaccine in 1962. Interestingly, Cuba was the first country to eliminate polio, due to a campaign of taking the vaccine to the people, going door-to-door to immunize every child in the country. That’s a lesson we could learn with COVID.

 

Changing the course of history in wars:

• ·      Revolutionary War: George Washington ordered smallpox inoculation (variolation) of the army, which affected the outcome of the war.
• ·      Haitian Revolution: yellow fever arrived from Africa aboard slave shops, along with its mosquito vector; slaves were more resistant to yellow fever but European slavers and Napoleon’s troops sickened and died.
• ·       War of 1812: a third of Napoleon’s army died of dysentery (Shigella) on the march to Moscow, and then most of the rest died of typhus (Rickettsia) on the march back to France.

Favorite Books of 2020

The only plus to a pandemic is more time for reading! 

Favorite books read in 2020:

• The Custard Protocol series (Prudence, Imprudence, Competence, Reticence), Gail Carriger – fiction, steampunk/vampires/werewolves/dirigibles.
• Untamed, Glennon Doyle – memoir and empowerment.
• Around the World in 80 Trees, Jonathan Drori – nonfiction, an ode to trees, with gorgeous illustrations. Did you know there is a tree called the Sève Bleue, which concentrates nickel in its sap, making the sap a crazy turquoise color? It’s being looked at for phytoremediation, using plants to remove toxic metals from the environment.
• Curators: Behind the Scenes of Natural History Museums, Lance Grande – nonfiction by a paleontology curator at the Field Museum in Chicago.
• The Relentless Moon, Mary Robinette Kowal – fiction, #3 of the Lady Astronaut series, alt-history/space travel/post-apocalyptic.
• The Stand, Stephen King – fiction, one of the three best pandemic stories ever (along with Wanderers by Chuck Wendig and World War Z by Max Brooks).
• Archaeology from Space, Sarah Parcak – nonfiction, using satellite imagery and remote sensing to discover thousands of new archaeological sites (Egyptian, Viking, Maya, etc.) and to combat looting and antiquities trafficking.
• Lovecraft Country, Matt Ruff – fiction, horror/sci-fi/racial injustice.
• Monarchs of the Sea, Danna Staaf – nonfiction, extinct and extant cephalopods and why they’re cool.
• The Book of Eels, Patrik Svensson – nonfiction about eels! Yes, eels! Science, history, mythology, and memoir.

  

  I heart cephalopods

My dog's cancer, Part II

I recently posted about Pippin's jaw cancer (fibrosarcoma). Unfortunately, he started declining and I made the hard decision to euthanize him on December 4. I'm still glad I pursued the mandibulectomy, because it gave him 9 happy months. He had a good summer and fall, going camping in the mountains, keeping our neighborhood safe from cats, bossing around the workers replacing our neighbors' roof, and hunting/eating grasshoppers in the yard.

Pippin Corgi, May 2, 2008 - December 4, 2020

My dog's cancer

Here’s a post about modern veterinary medicine and surgery, featuring my own dog, Pippin. Pippin is a 12-year-old neutered male Pembroke Welsh Corgi. Back in January 2020 I had him at work for a “dental.” I put that term in quotes; many pet owners and veterinary professionals use “dental” as a noun to describe a full dental procedure under anesthesia. But we’re trying to get away from using that term and instead using a term that more fully describes the procedure. At my hospital we call it an Oral ATP = oral assessment, treatment, and prevention. Other terms/acronyms are COHAT = complete oral health assessment and treatment, or OAT = oral assessment and treatment. Regardless of what you call it, it involves putting the pet under general anesthesia with an endotracheal tube in the trachea to provide ventilation and protect the airway, full-mouth radiographs (x-rays), scaling off the calculus (tartar), probing around each tooth for periodontal (gum) disease, and polishing the teeth.

 

Some places offer what’s called a “non-anesthetic dental” or NAD, but I do not recommend those. Basically it involves a technician scaling and polishing the teeth with the pet awake. The American Animal Hospital Association and the American Veterinary Dental College have both taken positions against NAD’s. When I talk to pet owners about NAD’s, I make these points:

• I hate going to the dentist. Scaling and polishing makes my anxiety spike and my head hurt. I’m a human and understand why I need to go to the dentist—pets don’t understand why they’re being held and someone is poking their mouth.
• Even the calmest pet will not allow full-mouth radiographs (x-rays) awake. Radiographs are absolutely necessary to look for pathology under the gumline, like abscesses, fractures, congenital abnormalities, or tumors.

 

Which brings us back to Pippin. His mouth looked fine; in the photo he is missing the upper tooth because he fractured it years ago and I extracted it. 

But on Pippin’s radiographs, I saw this splotchy black spot in the jaw around his lower left second and third molars (equivalent to our wisdom teeth).

My doctor brain and my pet owner brain started panicking.

Maybe it’s a congenital cyst? No, I’ve done radiographs on him multiple times in the past and that was never there before.

Maybe it’s an abscess? No, the black splotches are more diffuse and between the teeth, not centered around the tip of the root like an abscess would be.

Ugh, I think it’s cancer.

So I extracted the middle tooth and the surrounding bone and sent the chunk to the pathologist. The biopsy results came back as a sarcoma, or cancer. I took Pippin to a local specialty veterinary hospital where a board-certified veterinary dentist evaluated him. She did a CT scan of his head to see the extent of the tumor. These pictures show a generic dog skull with the location of the tumor in purple. The orange is the extent of the jaw that needed to be removed. 

Any time veterinarians or physicians are doing surgery to remove a cancer, you need to remove a margin of what appears to be normal tissue on all sides of the tumor. The reason for that is that cancer can be like an octopus—the tumor that you see with your eyes or x-rays or CT is the body of the octopus, but microscopic tumor cells can extend out like the arms of the octopus. To make sure you remove the entire tumor, you have to take at least a half-inch of healthy tissue on every side. In Pippin’s case, that meant such a large chunk behind the tumor that there was no point in leaving the ramus of the mandible, the part of the jaw that takes a left turn up to the joint with the skull.

A week or two later, Pippin had a caudal mandibulectomy. His surgeon removed the whole back half of his jaw and sutured the soft tissues together. He spent the night at the specialty hospital on heavy pain management. He was pretty sad for a couple days after coming home, with some swelling and oozing. The final biopsy report on the jaw was a fibrosarcoma, a potentially malignant cancer with a small (<20%) chance of metastasizing to other areas of the body.

First night home, in the "cone of shame"

To access the whole jaw and TMJ joint, his surgeon had to cut back from the corner of his mouth and then suture it back together.

A month after surgery, back to chewing on sticks!

Because there isn't actually any bone attachment on his left side, sometimes his jaw slides over to the side because of scar tissue. In this photo, you can see that his bottom jaw doesn't line up with his upper jaw. But the jaw only slides when he's being lazy; he can move it back into position when he wants to chew on a toy or eat dinner.

So far, so good! Here's Pippin on a family camping trip in August 2020. He's still feeling well now in November 2020.