In 2024, Brazil celebrated the 20th anniversary of the Bolsa Família Programme (BFP), one of the world’s largest conditional cash transfer initiatives. A new study published in The Lancet Public Health shows that the BFP has prevented more than 8.2 million hospitalisations and 713,083 deaths in Brazil between 2004 and 2019. In addition, it is estimated that an additional 683,721 deaths could be prevented if the programme's coverage is expanded by 2030.

A new study challenges the view that leprosy is a disease that was introduced into the Americas during European colonization. It reports that a strain of leprosy-causing mycobacterium, Mycobacterium lepromatosis, that was only discovered in recent years infected humans in the Americas longer ago – before European contact. The findings reshape current views of leprosy in the Americas and provide insights into the long-term interactions between humans and infectious diseases. There are two known mycobacteria that cause leprosy: Mycobacterium leprae and Mycobacterium lepromatosis. The former seems to have arrived in the Americas with European colonization and the latter was discovered in 2008 – and mostly reported in the Americas. To date, the only genomic data available from M. lepromatosis was obtained from three human samples from patients of Mexican origin and from seven red squirrels from Great Britain/Ireland, thereby limiting current understanding of the genetic diversity and history of the species. Here, Maria Lopopolo and colleagues sought to investigate the contemporary distribution and diversity of M. lepromatosis. They studied contemporary M. lepromatosis sequences, where data was available. To clarify the history and past prevalence of M. lepromatosis in the Americas, they also studied ancient DNA datasets from pre-European contact Ancestors from the Americas. Notably, the screening of pre-contact Ancestors uncovered three samples positive for M. lepromatosis in locations spanning the length of the Americas. “While our findings do not challenge the introduction of M. leprae leprosy into the Americas by European and African populations,” say the authors, “they reveal that M. lepromatosis was already circulating within human populations across the continent several centuries before the European arrival.”

 

Analysis of ancient proteins preserved in fossilized tooth enamel reveals insights into the elusive nature of Paranthropus robustus, researchers report. The findings, which challenge long-held assumptions about this early human relative, suggest greater diversity within Paranthropus than previously recognized and support the possibility of multiple distinct species within the genus. While advances in ancient DNA (aDNA) sequencing have enabled valuable insights into the evolutionary relationships of Middle to Late Pleistocene hominins, understanding of earlier Pliocene-Pleistocene species, like Paranthropus, remains limited. This is largely because aDNA does not survive well in African hominin fossils older than 20,000 years of age. Paranthropus, which lived between 2.8 and 1 million years ago alongside other early hominins like Australopithecus and Homo, has traditionally been viewed as a single evolutionary group. However, overlapping traits between Paranthropus robustus and Australopithecus africanus have raised questions about their potential evolutionary relationship. Moreover, variation in tooth structure suggests either hidden diversity within P. robustus or the presence of multiple separate species.

 

In lieu of aDNA, Palesa Madupe and colleagues used ancient proteins – which can persist far longer – to investigate variation within this ancient hominin species. Using high-resolution mass spectrometry and paleoproteomics techniques, Madupe et al. analyzed dental enamel proteins from four P. robustus fossils found in South Africa’s Swartkrans cave. These fossils, dated to between 1.8–2.2 million years ago, represent some of the earliest known of this species. Protein sequence analysis revealed molecular-level variation among the P. robustus individuals, including evidence of both male and female specimens – challenging the reliability of tooth-size-based sexing and suggesting that sexual dimorphism alone cannot account for the observed diversity in the fossil record. Notably, one individual appears genetically distinct from the others, which may indicate the presence of a different Paranthropus group or reflect substantial intraspecific variation. According to the authors, these findings align with recent morphological evidence pointing to previously unrecognized taxonomic diversity within the genus, including the proposed species P. capensis.

 

For reporters interested in research integrity issues, study lead author Palesa Madupe notes, “Paleoanthropology has a history of being dominated by scholars from predominantly White, Western institutions. This imbalance reproduces colonial dynamics, where foreign researchers often act as custodians of African sites, specimens (hoarding them), data and narratives, marginalizing local scholars and communities in both practice and recognition. We have worked to recenter knowledge production by including a large and diverse group of Africans right from the conceptualization stage of the research, in both lead and support roles, including reproducing analyses in South Africa (with a long-term goal of moving portions of the workflow to the continent). Our hope is that future research in the discipline will move away from helicopter research and towards more ethical and socially responsive science that centers African knowledge and uplifts the communities who are custodians of our fossil heritage.”

In a Perspective, Mark Hanson and Peter Gluckman explore how maternal stress, caregiving quality, and early environmental conditions can shape the development of executive functions and emotional regulation in children, and how these factors contribute to the emergence of anxiety disorders in young people. Mounting evidence reveals a significant rise in anxiety disorders among adolescents ages 12 to 19, especially in developing countries like the United States, which cannot be fully explained by contemporary stressful events like the COVID-19 pandemic. This pattern suggests that broader longer-term societal or developmental factors are driving the growing prevalence of adolescent anxiety. Here, Hanson and Gluckman highlight how environmental conditions in the earliest stages of life – beginning even before birth – can significantly shape a child’s developing brain, particularly the systems responsible for emotional regulation and executive functioning. According to the authors, these early cues may "prepare" children for adversity, but if the anticipated threats never fully materialize as they grow, such heightened emotional responses may lead to anxiety disorders, especially in adolescence. This mismatch is further compounded by the rapid and dynamic social and technological changes young people now face. “Societies face an emerging burden of mental health issues, especially in young people. Although appropriate interventions are needed to help those already affected, preventative approaches are also critical,” write Hanson and Gluckman. “Solutions will need to adopt a lifecourse perspective, involving more cohesive thinking about parental and caregiver support and the early childhood years by policymakers across health, education, and social welfare."

Nearly every human culture uses clapping to cheer, protest, pray or perform, but a new study reveals that the familiar gesture is as much a scientific event as it is a social one.

High levels of income inequality weaken support for raising the minimum wage, which in turn could further worsen income inequality as people believe this is the way things should be, according to research published by the American Psychological Association.