Cats deposit about 1.2 million metric tons of feces into the U.S. environment every year, roughly equivalent to 12 aircraft carriers, a new study finds, and all that poop may pose a public health hazard.
In a study published Tuesday in the journal Trends in Parasitology, two Maryland researchers studied an infectious parasite known as Toxoplasma gondii.
A new analysis by Dr. E. Fuller Torrey and Dr. Robert H. Yolken, scientists at Johns Hopkins University Medical Center, found that the parasite eggs, known as oocysts, may be more common than previously once known – perhaps between three and 434 oocysts per square foot of soil, according to samples taken from places as diverse as California, China, Brazil, Panama and Poland.
“It may be a much bigger problem than we realize,” said Torrey, a psychiatrist who heads the Stanley Medical Research Institute in Chevy Chase, Md.
“There’s increased awareness now that Toxoplasma gondii is a very clever parasite, and does strange things to the brain,” added Dr. E. Fuller Torrey. “That’s prompted us to re-evaluate it. It may be capable of doing more than we thought.”
Torrey and study co-author, Dr. Robert Yolken, a neurovirologist at Johns Hopkins Medical Center, write that “accumulating T. gondii oocysts in the environment pose a significant public health hazard, especially in the sandboxes of children, gardens and other places favored by cats for defecation.”
“It should be assumed that the play areas of children, especially sandboxes, are highly infectious unless they have been covered at all times when not in use, or … are not accessible to cats,” the authors wrote. “It should also be assumed that gardens to which cats have access are infectious, and gardeners should wear gloves and wash their hands after completing gardening…. Fruits and vegetables should be thoroughly washed.”
With the population of cats increasing in the United States, growing from 55 million to 80 million from 1989 to 2006, and the number of feral cats is estimated at between 25 million and 60 million. Studies show that approximately 1 percent of cats shed the infectious oocysts at any given time. These oocysts can survive for at least 18 months, and only a single one is needed to cause an infection, according to past research.
Researchers urge cat owners to keep their pets indoors and take precautions when it comes to kids’ sandboxes and backyard gardens. Also, they want you to dispose cat litter properly. Meaning, don’t flush it down the toliet and don’t throw it outside. Simply bag it, and dispose of it as you would the rest of your trash.
More research is needed to understand the risks posed by the Toxoplasma parasite. In the meantime, Torrey advocated controlling cat populations, especially feral ones.