Not-So-Silent Spring, or Here Come the Gardeners

FigureAs I write this, the annual Philadelphia Flower Show, the largest indoor flower, horticulture, and gardening exhibition in the world, is about to get underway. A major event in this city, the show heralds the imminent arrival of spring, with throngs of flower, landscape, and garden lovers descending on the city's convention center to ogle displays, attend workshops, pick up gardening tips, and shop for exotic flowers, bulbs, and accessories. This event is well-timed. The combination of warmer, frost-free weather, ample rainfall, and longer days make spring the ideal time for gardening. But gardeners, amateurs and professionals alike, should beware: Behind this seemingly innocuous activity, many threats are lurking! And many of them are going to end up in your emergency department. Soil Perils Starting with the familiar, Clostridium tetani is a non-encapsulated gram-positive rod that produces spores, thrives in anaerobic conditions, and is ubiquitous in soil. After being introduced into a wound, C. tetani proliferates and produces tetanospasmin, a potent neurotoxin that causes generalized muscular rigidity and autonomic nervous system dysfunction. Prevention is of paramount importance; all individuals with waning immunity (more than 10 years since their last tetanus shot) should be given a tetanus booster (Td or Tdap). There have been several recent outbreaks of Escherichia coli O157:H7 in raw food products; possibly because they were grown in soil that had been contaminated by manure-based fertilizers or by run-off from nearby livestock areas. At least one outbreak of Legionnaire's disease has been associated with potting soil (MMWR 2000;49[34]:777) and Giardia intestinalis, the most common intestinal parasite in the U.S., has been associated with outdoor activities and drinking contaminated water supplies (MMWR 2005;54[SS01]:9). Individuals who are immunosuppressed also must guard against exposure to histoplasmosis, coccidioidomycosis, blastomycosis, and other soil-borne opportunistic fungal infections. Zoonotic Threats A wide variety of arthropods such as bees, wasps, spiders, and ants are found in the garden. They are frequently the causes of bites, stings, and toxic, allergic, and anaphylactic reactions. Mosquitoes and ticks may be of greater clinical concern due to their prevalence and role in transmitting vector-borne diseases. Lyme disease, Rocky Mountain spotted fever, babesiosis, ehrilchiosis, and tularemia are all examples of common tickborne illnesses that are widely distributed in the continental United States. Unfortunately, because of their nonspecific prodromes and the fact that many patients who were bitten by a tick do not recall the event, these illnesses are often not recognized initially and become apparent only after they progress or complications arise. Mosquitoes, which breed in ponds, fountains, and other pools of standing water that are common in many gardens, also have been associated with transmission of West Nile disease and various types of equine encephalitis as well as more exotic diseases such as malaria, dengue, and yellow fever. Other bites and envenomations also are frequently encountered because gardens may harbor snakes, rodents, and other small mammals. Plant Dangers Many garden plants, as well as weeds growing wildly, have toxic effects. Jimson weed, deadly nightshade, moonflower, and mandrake all have anti-cholinergic effects. Jimson weed, one of the most common, contains atropine, hyoscyamine, and scopolamine that can be absorbed through contact, ingestion, or inhalation, leading to a wide range of symptoms from mydriasis (cornpicker's pupil) to a systemic anti-cholinergic toxodrome. Jimsonweed is also used as a recreational drug, and many accidental poisonings and overdoses have been reported. Philodendron, poinsettia, holly, and various species of mushrooms and peppers are commonly cultivated, displayed, or eaten, and also have been frequently associated with poisonings. (MMWR 1995;44[3]:41.) Additionally, Sporothrix schenckii, a fungus that is commonly found on plants, moss, and hay and in soil has been linked to sporotrichosis, known as rose gardener's disease. Transmission typically occurs after inoculation from a barb or spine puncturing the skin during handling and can lead to ulcerations at the site of inoculation, painless subcutaneous nodules along lymphatic drainage routes, or a systemic illness. Importantly, incision and drainage should be avoided because it may worsen the lesions. (MMWR 1988;37[42]:652.) Other Hazards Insecticides, herbicides, and pesticides (especially the organophosphates, carbamates, and superwarfarins) commonly used in gardens to increase plant yields and keep pests at bay can be harmful or deadly to humans. Dangerous exposures can occur accidentally or intentionally with systemic absorption occurring by the inhalational, transdermal, transconjunctival, or gastrointestinal routes. Children account for a disproportionately large number of accidental poisonings. Because of the wide variety of exposures, numerous brands, and multitude of chemical formulations and concentrations, treating physicians should consult their local poison control center whenever there is concern for a significant exposure. Recommendations Emergency physicians can help gardeners reduce these risks by advising them to avoid standing water and to run drainage away from composting piles or manure depots. Fertilizers and other chemicals should be safely stored out of the reach of children and used only as directed in well-ventilated areas. Tell patients to remove and discard unknown or unrecognized plants and weeds, and avoid wild animals. Because the garden is prime tick and mosquito habitat, gardeners should be advised to wear light-colored protective clothing (to aid in visualizing the ticks) including pants, long sleeved shirts, hats, and closed-toe shoes. Gardeners also should be encouraged to avoid being outdoors in the early morning or late afternoon, to use DEET-based insect sprays over their clothing, and to inspect their bodies carefully when they leave the garden. Bites and stings should be treated emergently. If a tick is found on the skin, it should be promptly removed by grasping the body with a pair of tweezers. The wound should then be washed and covered with an antibiotic dressing. (MMWR 2006;55[MM34]:933.) Gloves should be worn when cutting barbed or thorny plants, reaching into dark areas, or working near animal nesting areas. Recent CDC guidelines also recommend that immunosuppressed patients wear gloves while touching soil or plants, avoid creating plant or soil aerosols, wash hands thoroughly following contact, and care for skin lesions sustained during soil or plant contact.