4 . As I write this, a Bob Seger song is stuck in my head. It’s been playing on repeat ever since I heard it in a movie. I hated it a lot when it first came out years ago, and I still really hate it now. Why, oh why, does an earworm happen? This phenomenon, known as an earworm, is both fascinating and annoying. Earworms are a type of auditory imagery, where we perceive a tone without actually hearing it. When a familiar song is heard and suddenly stopped, some areas of the brain become overly activated in expectation of hearing the rest of the song, and then it fills in the missing pieces.

Anyone can experience earworms, but certain personality characteristics, like openness to experience, may increase their frequency. You may have seen a popular TikTok recently of a guy saying earworms aren’t normal but are instead symptoms of ADHD (多动症) or OCD (强迫症). That’s generally not the case. “It is entirely normal to experience earworms: Over 90% of participants in large-scale surveys report having had earworms at least once a week, and they are not a symptom of any other underlying mental condition,” says Jakubowski. Interestingly, earworms aren’t all bad. Research indicates that they can enhance our ability to recall past events, as the repetitive nature of the song strengthens our memory.

There are several strategies to get rid of earworms. Listening to the entire song can help resolve the unfinished loop. Alternatively, distracting yourself with another melody or engaging in activities that require focus can also be effective. Chewing gum or eating something crunchy may interrupt the song playing in your head. Despite these strategies, sometimes the best approach is to simply accept the presence of the earworm and let it fade away naturally. In my case, trying to actively rid myself of the song only made it more persistent. It seems patience is key when dealing with these stubborn musical guests in our minds.

5 . The Carter Center said recently that only 13 human cases of Guinea worm disease were reported worldwide last year. That is a major drop from 3.5 million cases of infected people in 1986, in which year the Atlanta-based Carter Center joined the World Health Organization( WHO) in the fight against Guinea worm disease. The center said the remaining infection occurred in four countries in sub-Saharan Africa. Six human cases were reported in Chad, five in South Sudan, one in Ethiopia and one in the Central African Republic. And the Central African Republic case remains under investigation.

Guinea worm disease is a disease that affects poor communities in distant parts of Africa and Asia where people do not have safe water to drink. People who drink unclean water can get parasites (寄生虫) that can grow up to 1 meter. The worm grows in people for up to a year before painfully coming out, often through the feet or other sensitive parts of the body.

The WHO says there is neither a drug treatment for Guinea worm disease nor a vaccine to prevent it. But it can be prevented by training people to filter (过滤) and drink clean water.

Guinea worm disease could be the second human disease to be ended after smallpox, according to the Carter Center. Adam Weiss, a director of a program to fight against the disease, says that eradicating the disease finally could be difficult, for the populations where Guinea worm disease still exists often face insecurity, including conflict, which can prevent workers and volunteers from going house to house to offer support.

Weiss warns, “If support for these communities slows or stops, there’s no question that you’re going to see a sudden increase in Guinea worm.” However, he adds, “We’re continuing to make progress — even if it is not as fast as we all want it to be, that progress continues.”

People may find it unbelievable that two hundred years ago people did not link illness to environmental problems.     1     (tragic), in London drinking polluted water led to the outbreak of cholera. It always started in the poor neighborhood, and then it spread to the richer areas as the servants     2     (infect) with the illness passed it on. Many     3     (specialist) suspected that polluted water was to blame. An     4     (influence) doctor, John Snow dedicated himself to     5     (tackle) the crisis, and found that the dirtier the water, the more severe the illness. Therefore, it was vital     6     water should be purified. They brought     7     the view that the handles should be removed from pumps if the water carried the virus. Thanks to John Snow’s devotion to     8     (combat) the virus, cholera was defeated eventually.