Three species of worms are more than 70% likely to cross the species barrier
Parasitic worms that infect companion animals such as dogs and cats are more likely to make the leap into humans than other worm species, according to new research from the University of Georgia’s Center for the Ecology of Infectious Diseases.
The study also identified three species of worms that don’t currently infect people but have a more than 70% chance of crossing into humans in the future.
“The close relationships that we have with pets is the predominant reason why people might become infected with new species of parasitic worms,” said Ania Majewska, lead author of the study and a doctoral graduate from the Odum School of Ecology. “Everyday behaviors like playing with and feeding our pets increase opportunities for those parasites to infect people.”
Dracunculiasis could be the second ever disease that humans have managed to eradicate, after smallpox, but dogs are hampering those efforts.
Scientists are warning that efforts to eradicate a debilitating parasite are being undermined by dogs eating infected fish.
Guinea worm disease used to affect millions of people a year in the 1980s, but eradication efforts have suppressed that number to just 27 documented human cases in 2020.
It would be the second ever human disease to be eradicated by modern medicine after smallpox, but just as it appeared to be on the cusp of eradication, scientists have discovered that domestic dogs are harbouring the parasite.
Researchers at the University of Exeter have published a study investigating how dogs - eating fish that carry the parasite larvae - are maintaining the Guinea worm's life cycle and passing the parasite on to humans.
Also known as Dracunculiasis, the disease historically infected humans when they drank water which contained water fleas infected with the parasite's larvae.
Once infected with the larvae there is no way to prevent the parasite from developing, first by penetrating through the digestive tract and then by escaping into the body where they mature and mate.
The mature adult Guinea worm - now potentially longer than a metre (three feet) - then migrates to what scientists call an "exit site" - usually a leg or an arm - and creates an extremely painful blister.