Pien Huang

Editor's note: This post was updated on Monday, Jan. 7.

O'Plerou Grebet is a 22-year-old graphic design student in Ivory Coast. Everywhere he looks, he sees signs of Western influence — from the glass skyscrapers and malls lining the streets in his home city of Abidjan to the way his peers spoke and dressed.

"We are living like we're Western people," he says. "It's like we are not proud of our own culture."

That even applies to the symbols he texts to friends using the messaging apps on his phone (they especially love to use the "tears of joy" face emoji, he says).

2019 is a record year for dengue fever in Latin America. The mosquito-borne disease has surged across the continent, from Mexico down to Chile and Argentina, with nearly 3 million cases reported.

You'd think that as a poor country grows wealthier, more of its children would get vaccinated for preventable diseases such as polio, measles and pneumonia.

But a review published in Nature this month offers a different perspective.

You might think that the more you clean, the less germy your home is.

That's what Laura-Isobel McCall, a biochemist at the University of Oklahoma, thought she'd find when she started comparing microbes between rural and urban homes in Peru and Brazil.

"We expected that all the microbes would actually become less diverse with urbanization, and that's not at all what we found for the fungi," she says.

Alexandra Chen was a trauma specialist working in Lebanon and Jordan when she noticed that a specific group of kids were struggling in schools.

Chen kept getting referrals for refugee students who had fled the war in Syria. They were having trouble focusing and finishing schoolwork. Some had even dropped out of school.

Better vaccines, nutrition and disease control have cut the global death rate for children in half over the past 20 years. But even within countries that have made major progress, children can face greatly different fates.

"Where you're born substantially impacts your probability of surviving to 5," says Simon Hay, an epidemiologist at the University of Washington who is the lead author of a new study on childhood mortality in Nature.

In 2015, Zika virus swept through Brazil and the Americas. It was the first time a mosquito-borne virus was known to cause severe birth defects, and the World Health Organization declared it a "public health emergency that warranted a global response."

Viktoriia Radchuk, an evolutionary ecologist at Berlin's Leibniz Institute for Zoo and Wildlife Research, wanted to know how animals were responding to climate change.

So she scoured the results of more than 10,000 animal studies — on species from frogs to snakes, from insects to birds to mammals — looking for information on how changing environments were affecting animal behavior. Based on the available data, she decided to focus on birds in the Northern Hemisphere.

Precision medicine is the field of dreams for human health. Drugs and treatments that would take into account a person's individual DNA configurations, as well as lifestyle and environment, would presumably be better tailored to each person's needs. Still, while the goal of precision medicine is to help everybody, the current research available has a major flaw. It's largely based on the genes of people who are predominantly of white and European descent.

Updated at 5:45 p.m. ET

Three summers ago, Ayse Tenger-Trolander, a graduate student at the University of Chicago, ordered a batch of monarch butterflies from a breeder, and made an accidental discovery: the butterflies had likely lost the ability to migrate.

The world's glaciers are melting faster than before, but it still takes decades to see changes that are happening at a glacial pace.