The H5N1 avian influenza virus can be transmitted between mammals, according to a study published in Nature. The research team isolated the virus from the milk of an infected cow in New Mexico (USA) and found that it spreads in mice and ferrets, reaching the mammary glands of both animals. In addition, the virus was also transmitted from infected lactating mice to their offspring. The European Centre for Disease Prevention and Control (ECDC) has issued a press release on Monday recommending increased surveillance for these viruses.

Talc has been classified as "probably carcinogenic to humans" by the International Agency for Research on Cancer (IARC), an agency of the World Health Organisation. In a statement, IARC reports that, after thoroughly reviewing the available scientific literature, the expert working group classified talc as probably carcinogenic to humans (Group 2A) "based on a combination of limited evidence of cancer in humans (for ovarian cancer), sufficient evidence of cancer in experimental animals, and strong mechanistic evidence that talc exhibits key features of carcinogens in human primary cells and experimental systems". In the same monograph, the agency classified acrylonitrile as "carcinogenic to humans" (Group 1). It is a chemical used in the manufacture of fibres for textiles, synthetic rubber and plastics. Both assessments are published in an article in The Lancet Oncology.

Wildfires increase the level of tropospheric ozone. An international study, published in The Lancet Planetary Health and involving Spanish participation, suggests that one- to three-day exposure to wildfire-related ozone pollution is linked to increased daily all-cause and respiratory mortality rates. The study analysed more than 700 locations - including in Spain - between 2000 and 2016, calculated the daily concentration of wildfire-related ozone pollution and compared it with data on daily deaths in the areas studied.

Research published in JAMA Network Open suggests that exposure to common environmental toxicants is associated with depressive symptoms. The authors analysed data from urine or blood samples from more than 3,400 US adults and found that 27 environmental toxicants were associated with these symptoms, which could be linked to inflammatory processes.

The use of the antidepressants escitalopram, paroxetine, and duloxetine is associated with greater weight gain than the use of sertraline, according to the results of an analysis comparing data from more than 183,000 adults treated with one of eight types of antidepressants. Among these, bupropion is associated with the least weight gain, concludes the study, which is published in Annals of Internal Medicine.

A new technique developed at the Institut de Bioenginyeria de Catalunya (IBEC) has succeeded in assessing the health of mouse oocytes and embryos in a non-invasive way, according to a study published in PNAS. The method generates 3D images to visualise the metabolism of oocytes and embryos obtained by in vitro fertilisation and makes it possible to select those that are most likely to implant and develop, say the authors.

A neuroprosthetic interface allows a bionic leg to respond to the nervous system of amputees to make walking faster and more natural, says a study published in Nature Medicine. The clinical trial involved 14 people with below-knee amputations: seven with a surgically attached bionic leg compared to seven without the interface.

The Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) has recommended granting marketing authorisation in the European Union for Eurneffy (epinephrine), the first nasally administered medicine for the emergency treatment of allergic reactions. Anaphylaxis is the most severe form of allergic reaction that can occur within minutes of exposure to an allergen and can be life-threatening. Until now, treatment with epinephrine (also known as adrenaline) to reduce the anaphylactic reaction is done by intramuscular injection. 

In a new study in mice published in Science, researchers present CHARM, an epigenetic editor that can be used to silence prion protein throughout the brain. The tool offers a path to effective first-line treatment for patients with fatal prion diseases, as well as other neurodegenerative diseases caused by the toxic accumulation of unwanted proteins. 

Two articles published in Nature describe a new genome editing technique that enables the insertion, inversion, or deletion of long DNA sequences at specific positions in the genome. This is a one-step approach that could offer a simpler method for genome editing in the future. The authors describe a technique to create reprogrammable recombinases—key enzymes in genetic recombination. These enzymes are guided by RNA, which acts as a bridge, directing the recombinase to target sites and facilitating predetermined editing.