Jordan was vague about the import of his discovery, but on more than one occasion he made his point about poop: The pileup of human excrement in the park is "unhealthy and unsanitary."
Indeed, there are many "unhealthy and unsanitary" creatures lurking in those unflushed logs. Human feces are about as rich a medium for transmitting disease as they come. According to the National Institutes of Health's Dr. Dennis Lang, a short list of the meatier bacteria with a taste for waste includes shigella, salmonella, and E. coli, not to mention hepatitis A and Cryptosporidium. Let's take a closer look at the dirty three.
Shigella, a bacterium whose existence is well documented in migrant farmer communities and Indian reservations where people live in outdoor camps, arrives as an intestinal infection. The bacteria invade the epithelial cells in the colon and cause severe cramps and bloody diarrhea.
Salmonella, better recognized because of its dubious recurrence in uncooked chicken, eggs, and dairy products, also has a nasty bite. An invasive organism like shigella, salmonella bacteria burrow into organ systems through the intestines. As with most fecal-oral diseases, the bacterium stokes inflammation and causes damage to the intestinal walls, which again provokes diarrhea. Once this organism gets into the bloodstream it can effect typhoidlike fevers and damage to the spleen and the liver in cases where the infection is not treated with haste.
Pathogenic strains of E. coli bacteria (those causing human disease) have special features. Not invasive organisms, E. coli live for a time in the intestines, releasing toxins that cause diarrhea, most dangerously the severely dehydrating diarrhea that can lead to death.
Then there are the parasites like the protozoan giardia. Giardia, with two nuclei and eight microscopic flagella, uses a small sucking disc to adhere to the lining of the small intestines. After weathering a sinister incubation period that can hide evidence of the parasite for several weeks, a person carrying the parasite will lose weight, suffer sever abdominal cramps, and excrete foul-smelling yellow-green feces in almost constant diarrhea for several weeks to several months.
Lang quickly points out the low probability of these diseases running with the homeless population, and moreover, the rare situation where they are passed along due to outdoor defecation. Citing Amtrak, whose train passengers flush waste directly to the tracks, Lang says there is little conclusive proof that exposed feces create problems unless they enter the water supply. According to Lang an irritating fly or a careless restaurant employee fingering salad greens would have a better shot at transmitting disease.
Even though she's heard the mayor's bombast about feces in the papers, Dr. Frances Taylor, who has been with the Department of Public Health in the city since 1986, says no fecal alarms have crossed her desk in recent weeks.
"It's been some time since I've been out to the park to look at fecal matter," she says. "I have no idea where any of the homeless defecate. But I'm not sure that in the back bushes of Golden Gate is more dangerous than a sidewalk."
Since it takes an infected person to pass along disease, Taylor adds that the volume of feces from an estimated 500 campers a night does not increase the health risk, only the probability of an infected camper who may dump a load chock-full of pathogenic bacteria. She explains the risk to recreational users of the park is nearly nil and says that the problems may be more with the appearance than with the disease.
Echoing that sentiment is Dr. Peter Schantz, the deputy chief of epidemiology at the division of parasitic disease at the Centers for Disease Control.
"The CDC has no official policy on parks, but personally I suspect that it is an aesthetic problem rather than a health problem -- no one wants to step in a pile of human shit.