I've been having some crappy mornings lately - literally.

I walk out my door, admire the contrast of the cherry blossoms against the crisp blue sky, and then hobble over a fresh mound of dog droppings. The Spring Garden section of Philadelphia is scattered with such treasures, occasionally encased in blue plastic bags. On trash day, I return home to a recycling bin containing at least three of these goody bags to bring back into the house.

Let's face it: Dealing with dog waste, whether you own a dog or not, is a fact of life. Increases in dog ownership in Philadelphia, however - coupled with an inadequate number of dog parks and absence of public garbage cans in residential areas - could turn a simple nuisance into a public-health problem reminiscent of early-19th-century America.

You don't need a graduate degree in public health to know that dog doo is gross, but some scientific facts make clear it's even worse.

Let's review:

Contrary to what one would think, many serious health risks associated with dog feces don't become apparent until well after man's best friend has done its business. The eggs of common parasites - Toxocara canis (a.k.a. roundworms), for example - don't turn infectious for days or weeks. When the feces dry out, the eggs can contaminate the soil below, sometimes for years. This obviously poses a serious risk to children who play in parks that are frequented by dogs.

In addition to parasites, dog poo (and most feces, for that matter) contains immense amounts of bacteria, including Giardia lamblia and harmful types of E. coli. When improperly disposed of, dog feces can contaminate local water sources. That happened in Florida, Virginia, and Idaho counties. And last summer, researchers implicated dog excrement as the source of much bacterial air pollution in select U.S. cities.

So, is the waste of Philadelphia's estimated 350,000 to 400,000 dogs causing health problems for its human residents? One can only speculate. What does seem evident, however, is a misalignment between the city's commitment to animal welfare and the infrastructure needed to support it.

As recently noted in the Daily News, the city is restructuring its animal-control activities in an attempt to find homes for all of its shelter animals. This is laudable, and hopefully will come to fruition. But are resources in the city capable of supporting its current dog population, let alone an increase?

For one, we need more dog parks. Because they are few and far between, some city parks (for people) have been commandeered by dogs and their owners - forcing sports teams to practice around droppings and discouraging both children and adults from exercising in some of the neighborhoods' only green spaces. This is bad for public health.

Denver, drawing from best practices in Portland, Ore., and New York, has developed a comprehensive plan to address its own dog-related needs. Philadelphia should consider doing the same.

Next, there seems to be a serious shortage of public trash cans in residential areas. It's a pretty good bet that some people would be more inclined to pick up after their dogs if they didn't have to bring the stuff home with them. A trash can full of dog doo may be a whole other can of worms - but still a step up from the poo-scattered streets we have now.

Finally, a bit of public awareness could go a long way. While it may be a well-established norm that picking up after your dog is "the right thing to do," some appeals highlighting the health risks associated with leaving feces where kids play might sway some of those who opt not to scoop. The Philadelphia Water Department is recruiting "spokesdogs" to help get the message out in one educational campaign.

A body of research suggests that canine companionship has benefits for human health. Dogs have coevolved with human civilizations for millennia, and will continue to do so for the foreseeable future. Dogs are great - in an urban setting, however, a bit of planning and investment is needed to ensure that the relationship between dogs and people, not just their owners, is a symbiotic one.