Zoobiquity (32 page)

When monster wildfires scorched southern Australia in 2009, destroying homes and killing nearly two hundred people, one photograph came to symbolize the epic clash of man against nature and the plight of the vulnerable creatures caught in the middle. It showed a firefighter in bright yellow battle fatigues. With smoke rising around him, he crouched on the charred earth, holding a plastic water bottle to the lips of an exhausted koala. As it drank, the animal gripped the firefighter’s hand with its small paw. The human—face sooty, hair mussed—gazed intently at the animal, a striking image of compassion and interspecies cooperation.

Around the world, people anxiously followed the story of the koala and the firefighter. At the shelter where the animal’s burns were salved and her paws bandaged, she acquired the nickname Sam. This icon of Australia—pulled from the ashes—became the furry face of resilience overcoming adversity, more phoenix than marsupial.

But six months later, Sam hit the blogs again. This time, her story didn’t have such a happy ending. In fact, Sam had died. It wasn’t the burns that had killed her. The koala was dead of complications from
chlamydia.
^*
She had a sexually transmitted disease (STD). Readers learned that chlamydia is an epidemic of such proportions among the thousands of wild koalas in Australia that it threatens extinction of the iconic animals.

Chlamydia and koalas. It’s a combination that just seems
wrong
, like a toddler with a heart attack. Small marsupials are innocent and natural, even cute. STDs, let’s be honest, are not. Even among physicians accustomed to the sights and smells of the human body, STDs hold little appeal.
An international survey of physicians once ranked afflictions by their level of prestige. Brain tumors, heart attacks, and leukemia were the top three. Diseases that strike below the belt were dead last.

And medical advances of the past half century have made it even easier to look away from sexual infections. In developed countries, most of us have the luxury of thinking of STDs as being essentially curable—or, at worst, treatable, chronic diseases requiring daily medication. (Think of antiviral medication for herpes or, in a more extreme case, daily drug cocktails for HIV.) What’s more, pervasive and effective “safe sex” education has given the strong message—true in some cases—that barrier methods and abstinence can make you practically impervious to STDs.

But for animals, safe sex isn’t a choice. In fact, when you think about it, unprotected sex is the only kind nonhuman animals have. Without access to condoms and abstinence pledges, not to mention antibiotics and vaccines, nonhuman animals have to cope and survive and reproduce somehow, regardless of what infections come their way. When you consider the amount of “unsafe” sex going on, 24/7, in a mere square mile of wilderness, it seems remarkable that animals aren’t 100 percent infected at all times with STDs.

Veterinarians, like physicians, often give animal STDs scant attention, compared to other health concerns. Wildlife veterinarians don’t regularly count the genital warts on tundra swan penises when they radio-collar them for migration surveys. Nor does yearly population
tracking of Yukon caribou end with the females in stirrups and the vet chitchatting while warming up an Arctic-chilled speculum. Even when zoos transport and relocate their animals for breeding, most don’t routinely screen for STDs.
Among biologists, the handful of professional academic organizations that might discuss animal STDs are loosely organized and spread thinly throughout the world.

Like most patients and physicians, I wasn’t exactly clamoring to hear more about STDs. But we all should pay attention, because STDs are remarkably deadly.
HIV/AIDS is the world’s sixth biggest cause of death. When you combine those numbers with cancer deaths from sexually spread viruses such as human papilloma virus (HPV) and hepatitis B and C, the mortality climbs even higher. STDs are tenacious, ancient, and lethal, and they continue to outfox human attempts to control them. Perhaps physicians can find help for human STD patients in a place they’ve never thought to look: the genitals of nonhuman animals.

Consider the following: Atlantic bottlenose dolphins sprout cervical and penile warts. Baboons get genital herpes. Copulating whales, donkeys, wildebeests, wild turkeys, and Arctic foxes harbor and transmit warts, herpes, infectious pustular vulvovaginitis, venereal pox, and chlamydia.

Sexually spread brucellosis, leptospirosis, and trichomoniasis cause repeated miscarriages and reduced milk output in cattle.
Pig litters can be decimated by bacterial infections acquired during mating.
Venereal diseases in farmed geese cause death as well as drops in egg production.
Contagious equine metritis so predictably devastates fertility in mares that every stallion of breeding age imported to the United States is required to go into a minimum three-week quarantine to make sure he’s not a carrier.
Dog STDs can cause abortions and birth failures.

When I first started learning about animal STDs, I was surprised by the range of species they infect. But it wasn’t too hard to picture the mechanics of mouse or horse or elephant sex and imagine the genital contact that could lead to the spread of an infection. What was truly eye-opening to me, however, was that the dark, balmy environments favored by sexually transmitted pathogens aren’t limited to warm-blooded creatures.
Dungeness crabs, for example, are vulnerable to a worm that spreads from males to females when they mate. The worms invade the female
looking for her cache of eggs. Once they find it, they start feeding, reducing the number of viable crab offspring.

Even insects carry STDs on their tiny genitals.
Two-dot ladybugs, one of the most promiscuous creatures on Earth, can become infected with a sexually spread mite that makes them sterile.
A postcoital housefly that lands hungrily on your freshly prepared Dungeness crab chowder may himself harbor a genital fungus, also acquired through copulation.
Astonishingly, some of the diseases we humans catch from insects—such as St. Louis encephalitis from mosquitoes and spotted fever from ticks—are actually sexually transmitted among the insects themselves. (If you’ve never pictured what ladybug or tick or housefly sex looks like, you have an illuminating twenty minutes of Internet image searching ahead of you. Most insects do engage in penetrative sex with genital contact—often in the doggy-style position.)

Indeed, STDs have been found thriving in so many living things, from fish and reptiles to birds and mammals and even
plants
, it’s safe to say they’re ubiquitous in all sexually active populations. Experts agree that these infections are legion.

And yet you might be whispering to yourself:
So what?
Yes, we want to reduce animal suffering. But in terms of human health, why should we give a moment’s thought to diseases of their genitals? To be blunt, since we’re not having sex with these animals, why should we care if some koala catches the clap?

The answer is as simple as it is unsettling: because pathogens are always looking for new paths, and they don’t differentiate between humans and other animals.
For example, rabbit syphilis once spread to trappers in East Yorkshire, who got sores on their hands after handling the animals. There was no sexual contact between the humans and the animals, but the syphilis pathogens didn’t care. They were happy to jump the species barrier and curl into warm moist tissue through cuts on the men’s hands.

Or think about brucella. In livestock,
these nasty bacteria cause spontaneous, late-term miscarriages in females and swollen, bleeding testicles in males. So unforgiving is brucella’s attack on the reproductive system that one of its common strains is called
Brucella abortus
. But what’s instructive about brucella is how it spreads.
Cattle, pigs, and dogs transmit it through sex. So do hares, goats, and sheep. But all these animals
can also acquire it nonsexually … by eating it. Under the right conditions, brucella organisms can live for several months on many things that might end up in an animal’s mouth: feed, water, equipment, and clothing, not to mention manure, hay, blood, urine, and milk.

In a number of animals, the same pathogen has found two different paths of entry into the body—sexual and oral. Through the mouth is the way humans usually acquire brucella infections, too—when they eat contaminated meat, unpasteurized milk, or soft cheeses. Spread this way, from animals to humans,
brucellosis is a major public health concern, especially in developing countries, where thousands of cases emerge each year. (
In developed countries, it has become mercifully rare, thanks largely to veterinarians who vaccinate animals and monitor the spread of disease.)

Like livestock, humans can become infected with brucella in more than one way. Like the trappers who contracted syphilis infections by touching sick rabbits,
zookeepers in Japan got brucellosis when, during the delivery of an infected baby moose, they came in contact with the placenta and mother’s vaginal secretions.

And although they’re rare, reports do exist of brucella’s spreading from human to human—through blood, milk, and bone marrow … as well as through sexual intercourse.

Same pathogen. Different paths. Could classifying a condition as “sexually transmitted” be limiting how we consider and understand these infections? After all, bugs are bugs, no matter how they get in.
Streptococcus A
, the common human pathogen that causes strep throat, scarlet fever, and rheumatic heart disease already exploits several routes into the body. Its most common path is respiratory. One person coughs or sneezes droplets containing the bacteria, and another person inhales or picks them up from doorknobs or silverware. But Strep A can, through oral-genital contact, cause penile inflammation and purulent discharge. You can get salmonella from sex with an infected person or by licking raw cookie dough off your finger—either way you’ll be down for the count with 104-degree fever, hideous diarrhea, and exhaustion. Hepatitis A, as well, can be picked up during a sexual encounter or by eating at a restaurant where the chef didn’t heed the hand-washing instruction sign in the bathroom. No matter which portal it uses to enter your body, the pathogen will give you the same gruesome symptoms: fever, exhaustion,
and a complexion the color of Grey Poupon. You might even need a liver transplant.

Studying STDs in animals reminds us that, like all living things, pathogens are constantly evolving. Species suited to one region of the body can change over time, developing new areas in which to live and thrive. Take
Trichomonas vaginalis
.
Nowadays, “trich” is one of the least glamorous but most common STDs. In women it causes a fishy-smelling, frothy, yellow-green vaginal discharge. Men infected with trich usually have a slight irritation or burning in the penis, but no other symptoms.
But contemporary
T. vag
wasn’t always a lowly genital dweller.
Ancient, ancestral
T. vaginalis
resided in the digestive tracts of termites. This made it, essentially, a gastrointestinal bug. Changes over trillions of generations (and millions of years), however, allowed it to expand beyond termites and guts into the bodily crannies of many different animals. Eventually a version found its way to human vaginas (and fifteen minutes of microbial celebrity in 2007 when it was featured as
Science
magazine’s “cover bug”).

Today, cousins of
T. vaginalis
(descendants of that ancient termite-dwelling ancestor) don’t limit themselves to human penises and vaginas. Other species of trich have found suitable homes in various parts of human and animal bodies.
T. tenax
,
for example, thrives in the dark, moist crevices of rotting teeth.
T. foetus
causes chronic diarrhea in cats and ravages the fertility of cows.
T. gallinae
is practically endemic in the mouths of many birds—voracious raptors and peace-loving doves alike.