Becker said 600 children every year go blind from parasites commonly found in gardens, lawns and outdoor areas. Animals pass the parasites in their feces and children playing outside then may get contaminated, touch their mouths and contract the bug.
"They put their fingers in the dirt and the dirt in their mouth," Becker said. "These larval worms realize they are in the wrong host and start wandering around."
Unfortunately, the worms may wander into the retina and cause blindness. In total, 700 people lose their vision from a zoonotic parasite each year, according to the CDC.
Furry friends are easy targets for deer ticks, or as Becker calls them, "heinous hitchhikers," which thrive in wooded areas in the Northeast.
Once outside, even on the leash, a tick can hitch a ride on your dog or cat, and then infect you with Lyme disease. More than 25,000 people reported Lyme disease infections to the CDC last year.
Pets also can pick up the American dog tick and Rocky Mountain wood tick while playing outside. These ticks carry the severe infection of Rocky Mountain spotted fever. Although discovered in the Rocky Mountains, the disease is far more common in the Southeast and Mid-Atlantic regions and affects 250 to 1,200 people each year, according to the CDC.
Becker noted the prevalence of tick-borne diseases recently motivated organizations including the non-profit Companion Animal Parasite Council [CAPC] to ask pet owners everywhere to fight parasites year-round.
"People would try to time parasite control for the seasons, but often they'd forget," said Becker. "They [CAPC] don't care where you live, they ask for lifetime parasite control for all pets."
Rowell noted that pet birds can carry the diseases psittacosis and cryptococcus.
Meanwhile, Becker warned that cats put their owners at eight times the normal risk for contracting the superbug MRSA. But he added people can cut the risk and keep the pet by following good hygiene.
"You don't want to clean the cages out in the same place you prepare food," said Becker, who added people should never wash water dishes or pets in the kitchen sink.
Becker noted that keeping a yard clean can also go a long way to prevent roundworm and other parasites from infecting young children.
"If you pick up your yard every other day, the feces won't get to the infective stage," explained Becker.
Not allowing your pet to lick your face can also stop the spread of parasites. Keeping open wounds covered will stop other infections, as will good, old-fashioned hand washing.
"With most healthy people and the usual good hygiene, it's not a common problem," said Rowell. "The most common thing I can think of is toxoplasmosis in pregnant women."
Rowell recommended pregnant woman ask someone else to change their cat litter when they're pregnant, avoid digging outside in the garden and wash their hands if they do touch soil.
Despite the variety of pet-to-human diseases, Becker pointed out that most of them are non-lethal.
"You don't read in the news of veterinarians dropping dead of these zoological diseases ... like Ebola and bird flu," said Becker.