Parasitic worms found in dogs and cats are more likely to infect humans, study says
Strands of parasitic worms found in dogs and cats are more likely to infect humans than other worm species, researchers said.
The study found that 137 of the 737 worm species analyzed may cause infections in humans, according to a Dec. 21 news release from the University of Georgia’s Center for the Ecology of Infectious Diseases.
Nearly 1.5 billion people worldwide are infected with soil-transmitted parasitic worms, also known as helminths, according to the World Health Organization.
Ania Majewska, lead author of the study and an ecology doctoral graduate with the university, and the team found worms that infect companion animals or fish have a higher chance of causing human infections than worms that live in other animal species.
“The close relationships that we have with pets is the predominant reason why people might become infected with new species of parasitic worms,” Majewska said in the release. “Everyday behaviors like playing with and feeding our pets increase opportunities for those parasites to infect people.”
The study, published in The Royal Society journal Philosophical Transactions B last month, categorized traits found in various worm species and used a machine learning model to “determine which characteristics were most commonly associated with transmission into humans.”
Tapeworms, roundworms and flatworms were found to cause chronic infections of the gastrointestinal tract, according to the study.
Three worm species may cause future infection
Researchers also found that three species of worms that don’t infect people now have a 70% chance of transmitting disease in the future.
That’s because they have certain traits that make humans perfect hosts, according to the release. Those parasites include:
Paramphistomum cervi: a flatworm usually found in livestock and some wild animals.
Schistocephalus solidus: a fish-based tapeworm that lives in birds and rodents.
Strongyloides papillosus: a pinworm that is found primarily in livestock.
The study is the first of its kind to identify the likelihood of these parasites infecting humans, according to the release.
“Our pets can become infected with helminths without us noticing,” Majewska said in the release. “Dogs and cats, particularly those that freely roam outside, come into contact either directly or indirectly with wild animals, their excrements and other sources of helminths.”
Don’t consume raw fish
But dogs and cats aren’t the only ones who can transmit parasites to humans. Fish are ideal candidates, too.
People who consume raw, undercooked or poorly prepared fish are susceptible to parasites, researchers said.
For example, roundworms that cause herring worm disease infect thousands of people each year, especially in Japan and parts of Europe, where consuming raw fish is common.
“Human parasitic worm infections have ancient origins, and we will always be associated with them,” said senior author John Drake, the university’s distinguished research professor of ecology and director of the Center for the Ecology of Infectious Diseases. “However, because of climate change and increased demands for animal protein, we fully expect that human parasitic worm infections will continue to increase. More research is needed to understand how parasitic worm spillover to humans can be managed.”
This story was originally published December 22, 2021 at 5:31 PM with the headline "Parasitic worms found in dogs and cats are more likely to infect humans, study says."
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