Toxocara parasite moving under the microscope “It’s really important for us to understand that these neglected tropical diseases, Toxocara being one of them, are still a huge problem the extent of which we don’t yet know, because we really haven’t looked.” “I think their finding of Toxocara is both important and unsurprising,” said Thomas Nutman, chief of the laboratory of parasitic diseases at the National Institute of Allergy and Infectious Diseases. The higher contamination rate may also be related to the ability of pet owners to pay for regular veterinary check-ups and deworming. “In a lower socio-economic area, there’s a lot more stray dogs and cats roaming around,” Tyungu said.

In general, the eggs all over the city tended to come from a species of Toxocara specific to cats rather than dogs. Manhattan, by comparison, has the highest median income but the lowest percentage of contamination, with 29.6% – or eight of 27 – of sites testing positive for Toxocara eggs. Toxocara eggs were found in 66.7% – or 10 of 15 – of tested playgrounds. The highest number of positive samples came from the Bronx, where more than half of the population are people of color and the median household income was roughly $42,000 in 2020. In the New York study, published in 2020, the scientists took samples from 91 parks and playgrounds in the five boroughs. “Pet owners should be aware that their dogs can get infected by something they eat off the ground.” “People, especially those with children who tend to play in the sand or soil, should be aware of Toxocara,” said Donna Tyungu, lead author of the New York paper and a pediatric infectious disease specialist who researches parasites at the University of Oklahoma. In the US each year, at least 70 people, mostly children go blind as a result of toxocariasis, the disease caused by Toxocara, but the researchers say that is probably an underestimate, as a general pediatrician might not easily recognize the illness. In very rare cases, the parasite can reach the eye, causing blindness, and cause neurological damage in the brain.

Even so, the scientists say, most infections are asymptomatic, though sometimes symptoms may include fever, fatigue, coughing, rash, or abdominal pain. But this means children are at a higher risk. It’s not that easy for humans to become infected – they must literally consume infected dirt. The presence of Toxocara is not necessarily a cause for alarm, the researchers say.

Around the world other researchers are also finding Toxocara in parks. In New York City, one of the locations of the studies performed in recent years, these parasites are present in parks in all five boroughs, and there are more of them in parks in more impoverished neighborhoods.

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