Previous exposure to the dengue virus may increase the potency of Zika infection, according to research from Imperial College London.

The early-stage laboratory findings, published in the journal Nature Immunology, suggests the recent explosive outbreak of Zika may have been driven in part by previous exposure to the dengue virus.

The study, which included scientists from Institut Pasteur in Paris and Mahidol University in Bangkok, suggests the Zika virus uses the body's own defences as a 'Trojan horse', allowing it to enter a human cell undetected. Once inside the cell, it replicates rapidly.

As people get older, they become choosier about how they spend their time and with whom they spend it. Now, researchers reporting in the Cell Press journal Current Biology on June 23 find, based on a series of experimental and behavioral studies, that similar changes take place in Barbary macaques. The findings offer an evolutionary perspective on why aging humans behave as they do, according to the researchers.

The reason why treadmill training can boost memory recall remains an active area of investigation. A couple of proteins have been shown to fuel exercise-induced neuron growth, but a June 23 study in Cell Metabolism presents a new candidate, cathepsin B--one that can be directly traced from the muscles to the brain in mice. Also, after a run, protein levels increased in blood in mice, monkeys, and humans.

"We wanted to cast a wide net. Rather than focus on a known factor, we did a screen for proteins that could be secreted by muscle tissue and transported to the brain, and among the most interesting candidates was cathepsin B," says senior author Henriette van Praag, a neuroscientist at the National Institute on Aging in the United States.

DURHAM, N.C. -- By combining super-fine electrodes and tiny amounts of a very specific drug, Duke University researchers have singled out a circuit in mouse brains and taken control of it to dial an animal's mood up and down.

Stress-susceptible animals that behaved as if they were depressed or anxious were restored to relatively normal behavior by tweaking the system, according to a study appearing in the July 20 issue of Neuron.

PRINCETON, N.J.--Pregnant women in Latin American countries were more likely to seek an abortion after receiving health alerts about Zika virus, according to a study co-authored by Princeton University researchers and published in the New England Journal of Medicine.

The researchers analyzed data from Women on Web -- an online portal that pairs patients with doctors able to prescribe abortion pills -- and found that many Latin American women using the site reported Zika as their reason for seeking an abortion. Because abortions are illegal or highly restricted across much of Latin America, many pregnant women seek outside options like Women on Web, which serves women who are less than 10 weeks along in their pregnancy and have no severe illnesses.

The implementation of state prescription drug monitoring programs was associated with the prevention of approximately one opioid-related overdose death every two hours on average nationwide, according to a new Vanderbilt-led study released June 22 in the journal Health Affairs.

States with the most robust programs saw the greatest reduction in overdose deaths: these states monitored and tracked a greater number of substances with abuse potential and updated their data more frequently (at least weekly).