Just as health officials were on the cusp of conquering Guinea worm disease, an outbreak in dogs may be spreading the worms back to humans in Chad, Nature reports. People ingest Guinea worm larvae when they drink contaminated water, and adult female worms later crawl from peoples’ legs or feet—an excruciating process that can take weeks. A global effort to educate people and improve sanitation has nearly eradicated Guinea worms, cutting cases from millions in the 1980s to a couple dozen in 2015. The type of Guinea worms that infect humans once specialized almost entirely on our species, but in the last year more than 450 cases were reported in dogs in Chad. Health workers are now targeting canine infections in an effort to wipe out the parasites once and for all.
Read our COVID-19 research and news.