A new study has found that a parasite typically found in humans is also present in domestic dogs and, to a lesser extent, in cats.<\/p>\n
The results were published in Veterinary Research Communications<\/a>, led by scientists at Wroc\u0142aw University of Environmental and Life Sciences in Poland.<\/p>\n The parasite Trichomonas tenax<\/a> is a mouth scavenger that feeds on microbes tucked between the teeth and around the gums.<\/p>\n Most people don’t even know their mouth is home to this parasite, and while it doesn’t always cause health problems, it has been linked to some periodontal infections.<\/p>\n T. tenax can be spread through saliva, and some studies have found it in dogs, cats, and horses<\/a>, too.<\/p>\n The new research from Poland can’t establish whether our pets are getting these oral parasites directly from us, but that is a possibility.<\/p>\n Scientists collected oral swabs from 238 household animals in Poland, including 151 dogs and 87 cats.<\/p>\n When they cultured the samples, they found trichomonads in 17 percent of the dog swabs and nearly 6 percent of the cat swabs.<\/p>\n T. tenax was one of the only parasite species detected in both dogs and cats. It was the second most frequently identified trichomonad.<\/p>\n Among dogs, pets over 9 years of age and those with severe tartar deposits on their teeth were more likely to host oral trichomonads.<\/p>\n Housing conditions may also play a role, though the difference wasn’t statistically significant.<\/p>\n For instance, all the cats with oral trichomonads were indoor animals, with limited contact with the outside world but closer contact with humans.<\/p>\n “Therefore,” the authors suggest<\/a>, “the primary source of infection seems to be humans, for whom T. tenax is considered a typical species.”<\/p>\n That may be why dogs have higher rates.<\/p>\n Compared to cats, researchers in Poland explain<\/a>, our dogs “generally have greater opportunities for contact with other individuals and the external environment, which is associated with a higher risk of infection.”<\/p>\n “Additionally,” they add<\/a>, “cats are typically more reserved in interactions with conspecifics and often have limited exposure to the external environment\u2026 “<\/p>\n For now, this is only a hypothesis, but the sharing of oral germs could have health implications for both us and our pets.<\/p>\n Oral trichomonads, for example, can produce proteins and enzymes that damage collagen fibers and promote soft tissue loss.<\/p>\n Sometimes, they are even found outside the mouth, in the tonsils or lymph nodes.<\/p>\n “Despite clear evidence of their role as pathogens, trichomonads remain poorly understood in dogs and cats,” write<\/a> researchers in Poland, led by Agnieszka Piekara-St\u0119pi\u0144ska.<\/p>\n “These domestic animals are particularly important due to their close contact with humans, which increases the risk of transmission of pathogens with a zoonotic potential.”<\/p>\n Zoonotic potential means the ability for a pathogen to jump from one species to another.<\/p>\n Toxoplasma gondii is perhaps the most famous of parasites<\/a> that can jump between our pets and us.<\/p>\n Cats are its typical host, but it can also end up in our own brains and stay there for decades.<\/p>\n Most cases don’t cause health issues, but in children or those with suppressed immune systems, severe flu-like symptoms<\/a> can occur, as well as blurred vision and brain inflammation.<\/p>\n The parasite’s presence in humans is associated<\/a> with schizophrenia.<\/p>\n To find out whether T. tenax is also associated with health issues, however, will require more research.<\/p>\n The trouble is, scientists have measured widely different rates of trichomonad infections in our pets, depending on where in the world they look, and what subset of pets they consider.<\/p>\n A previous study in Poland, for instance, found a lower rate of infection among dogs, and in the neighboring Czechia, researchers found oral trichomonad prevalence reaches nearly 38 percent in dogs and 10 percent in cats.<\/p>\n That latter study, however, also included shelter pets, which makes the two sets of figures harder to compare directly.<\/p>\n More rigorous studies are needed to pinpoint which of our pets are most affected by human-associated oral parasites, and how these microbes may be related to health.<\/p>\n The research has been published in Veterinary Research Communications<\/a>.<\/p>\n This article was fact-checked by Rebecca Dyer<\/a> and edited by Rebecca Dyer<\/a>. While we pride ourselves on our process, we are only human. If you spot a mistake, please let us know<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"There’s a common myth that a dog’s mouth is cleaner than a human’s. 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