Little things, like taking a shortcut through the park on your way to work each day can make a big difference

to your mental health. Find your little big thing

little big thing at every mind matters. This is scientific Americans 60 Second Science. I'm Waite Gibbs.

I'm a big fan of sushi and Civiche, so I was alarmed to see the headline on a recent news release from the University of Washington stating that sushi parasites have increased

283 fold in the past 40 years.

But after digging into the research, which came out of a marine ecology lab run by Chelsea

Wood at UW Seattle campus, I learned that the rising abundance of marine worms known

as anisacids is actually less of a problem for people than it is for whales and dolphins, which are the natural hosts infected by those parasites.

Woods team did what's known as a meta analysis. They collected data

from a hundred and twenty three papers published over the past half century that

estimated parasite abundance in various species at sites all over the world between 1967 and 2017.

Their analysis, published last month in the Journal Global Change Biology, found that since

1978 when less than one worm was seen in every 100 host animals on average,

the prevalence of anisacid parasite infection has skyrocketed,

to the point that more than one worm is now typically seen in every host animal examined in 2015.

Anisacid worms grow in the guts of whales.

Spread to krill through the whale's poop and then move up the food chain to squid and small fish like anchovies,

then to big fish like salmon, tuna, and halibut, and finally to humans.

In the US and most parts of Europe, fish and squid served raw must first be frozen to kill the nematodes in their larvae, which are big enough to see with the naked eye.

And even if you're unlucky enough to eat live anisached larvae in your sushi, saviche or gravlox, you'll probably be fine.

The worms rarely survive long enough in the human gut to cause anisociasis, which typically

involves abdominal pain and vomiting.

...