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Study Reveals Essential Genes That Help Tuberculosis Survive Airborne Transmission

Tuberculosis is a respiratory disease caused by Mycobacterium tuberculosis, a bacterium that predominantly affects the lungs and spreads through droplets released by an infected person

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Image credit: Jomar Junior from Pixabay

Tuberculosis thrives in the lungs, but when the bacteria causing the disease are expelled into the air, they face a much harsher environment with drastic changes in pH and chemistry. Understanding how these bacteria survive this airborne journey is essential for their persistence, yet little is known about the mechanisms that protect them as they move from one host to another.

Now, MIT researchers and their collaborators have identified a family of genes that are crucial for the bacterium’s survival specifically when exposed to the air, likely offering protection during its transmission.

Previously, many of these genes were thought to be nonessential, as they didn’t appear to affect the bacteria’s role in causing disease when introduced into a host. This new study, however, suggests that these genes are vital for transmission rather than proliferation.

“There is a blind spot in our understanding of airborne transmission, especially regarding how a pathogen survives sudden environmental changes as it circulates in the air,” says Lydia Bourouiba, head of the Fluid Dynamics of Disease Transmission Laboratory, associate professor of civil and environmental engineering, mechanical engineering, and core faculty member at MIT’s Institute for Medical Engineering and Science. “Now, through these genes, we have an insight into the tools tuberculosis uses to protect itself.”

The team’s findings, published this week in Proceedings of the National Academy of Sciences, could lead to new tuberculosis therapies that target both infection and transmission prevention.

“If a drug targeted the products of these genes, it could effectively treat an individual and, even before that person is cured, prevent the infection from spreading,” says Carl Nathan, chair of the Department of Microbiology and Immunology and the R.A. Rees Pritchett Professor of Microbiology at Weill Cornell Medicine.

Nathan and Bourouiba co-senior authored the study, which includes MIT collaborators and Bourouiba’s mentees from the Fluids and Health Network: co-lead author postdoc Xiaoyi Hu, postdoc Eric Shen, and students Robin Jahn and Luc Geurts. The research also involved collaborators from Weill Cornell Medicine, the University of California at San Diego, Rockefeller University, Hackensack Meridian Health, and the University of Washington.

Pathogen’s Perspective

Tuberculosis is a respiratory disease caused by Mycobacterium tuberculosis, a bacterium that predominantly affects the lungs and spreads through droplets released by an infected person, typically when they cough or sneeze. Tuberculosis remains the leading cause of death from infection, except during global viral pandemics.

“In the last century, we’ve seen the 1918 influenza pandemic, the 1981 HIV/AIDS epidemic, and the 2019 SARS-CoV-2 pandemic,” notes Nathan. “Each virus has caused significant loss of life, but after they subsided, we were left with the ‘permanent pandemic’ of tuberculosis.”

Much of the research on tuberculosis focuses on its pathophysiology—how the bacteria infect a host—along with diagnostic and treatment methods. For their new study, Nathan and Bourouiba turned their attention to tuberculosis transmission, specifically exploring how the bacteria defend themselves during airborne transmission.

“This is one of the first efforts to study tuberculosis from an airborne perspective, investigating how the organism survives harsh changes in the environment during transmission,” says Bourouiba.

Critical Defense

At MIT, Bourouiba studies fluid dynamics and how droplet behaviors can spread particles and pathogens. She partnered with Nathan, who investigates tuberculosis and the genes that the bacteria rely on throughout their life cycle.

To explore how tuberculosis survives in the air, the team aimed to replicate the conditions the bacterium encounters during transmission. They first worked to develop a fluid with similar viscosity and droplet sizes to those expelled by a person coughing or sneezing. Bourouiba points out that previous research on tuberculosis relied on liquid solutions that are used to grow the bacteria. However, these liquids differ significantly from the fluids tuberculosis patients expel.

Furthermore, the fluid typically sampled from tuberculosis patients, like sputum for diagnostic tests, is thick and sticky, which makes it inefficient at spreading and forming inhalable droplets. “It’s too gooey to break into inhalable droplets,” Bourouiba explains.

Through her research on fluid and droplet physics, the team determined a more accurate viscosity and droplet size distribution for tuberculosis-laden microdroplets in the air. They also analyzed the composition of droplets by studying infected lung tissue samples. They then created a fluid that mimicked the viscosity, surface tension, and droplet size that would be released into the air when a person exhales.

Next, the team deposited different fluid mixtures onto plates as tiny droplets, measuring how they evaporated and what structures they left behind. They discovered that the new fluid shielded the bacteria at the center of the droplet, unlike traditional fluids where bacteria were more exposed to the air. The realistic fluid also retained more water.

The team then infused the droplets with bacteria carrying genes with various knockdowns to see how the absence of specific genes affected bacterial survival during evaporation.

They evaluated over 4,000 tuberculosis genes and identified a family of genes that became crucial in airborne conditions. Many of these genes are involved in repairing damage to oxidized proteins, such as those exposed to air, while others are responsible for breaking down irreparably damaged proteins.

“What we found is a lengthy list of candidate genes, some more prominently involved than others, that could play a critical role in helping tuberculosis survive during transmission,” Nathan says.

While the experiments cannot fully replicate the bacteria’s biophysical transmission (as droplets fly through the air and evaporate), the team mimicked these conditions by placing plates in a dry chamber to accelerate droplet evaporation, similar to what happens in flight.

Going forward, the researchers are developing platforms to study droplets in flight under various conditions. They plan to further investigate the role of the newly identified genes in more realistic experiments, potentially weakening tuberculosis’s airborne defenses.

“The idea of waiting to diagnose and treat someone with tuberculosis is an inefficient way to stop the pandemic,” Nathan says. “Most individuals who exhale tuberculosis haven’t been diagnosed yet, so we need to interrupt its transmission. Understanding the process is key, and now we have some ideas.”

EP Staff is the editorial team at EdPublica, an independent media organisation focused on science, education, environment and public policy. The team produces evidence-based news, features, explainers and analysis on issues that shape society and everyday life.

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NMC Directs Medical Colleges to Set Up Patient Safety Committees

The National Medical Commission has directed medical colleges and medical institutions to establish patient safety committees, designate nodal officers and strengthen procedures to prevent avoidable harm.

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NMC: Medical professionals in protective equipment review documents during a patient safety meeting.
Medical professionals review documents during a meeting, highlighting the importance of coordinated safety practices in healthcare institutions. Representational image. Image credit: Dave Gracia/ Pexels

The National Medical Commission (NMC) has directed medical colleges and medical institutions across India to establish Patient Safety Committees or Cells and designate Patient Safety Nodal Officers to strengthen safety practices and reduce preventable harm in healthcare settings.

The Commission asked the heads of medical institutions to share the composition of their committees and the details of the designated nodal officers with the National Patient Safety Secretariat (NPSS) under the Directorate General of Health Services (DGHS).

The directive follows a communication dated May 8, 2026, from the Additional Director General of Health Services in the Union Ministry of Health and Family Welfare. It seeks to strengthen the adoption of patient safety protocols and standard operating procedures across medical institutions.

NMC’s Multidisciplinary Oversight

The proposed committee will be chaired by the director, head of the institution or medical superintendent. Its membership must include representatives from relevant medical specialties and the patient safety domains identified by the NPSS. Institutions are also advised to designate a nodal officer with sufficient seniority and authority to coordinate safety initiatives.

The framework covers 11 patient safety domains, including medication safety, surgical safety, blood transfusion safety, medical device safety, laboratory and diagnostic safety, infection prevention and control, healthcare-associated infections, antimicrobial resistance, patient and family engagement, vaccine and injection safety, and facility safety. It also encompasses operational research in patient safety and safety in AYUSH services.

The scope extends beyond clinical treatment to areas such as biomedical waste management, fire safety, structural safety and environmental safety. Nursing, hospital administration and other relevant professionals can contribute to the committee’s work.

From Protocols to Institutional Accountability

The directive places responsibility for patient safety within an organised institutional framework. Rather than leaving safety measures to individual departments or healthcare professionals, the proposed mechanism brings clinical, diagnostic and administrative functions under coordinated oversight.

The committee’s terms of reference include reviewing patient safety incidents and near misses, analysing their causes, promoting reporting and recommending corrective and preventive measures. Such reviews can help institutions identify weaknesses in procedures and address risks before they result in further harm.

The effectiveness of these committees will depend on how consistently institutions implement safety protocols, review incidents and act on their findings. Establishing a committee is an administrative step; sustained monitoring and corrective action are essential to translating the framework into safer care.

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World Food Day: India’s Childhood Obesity Burden Raises Concerns Over Diabetes Risk

More than 41 million Indian children and adolescents aged 5–19 were living with overweight or obesity in 2025, according to the World Obesity Atlas 2026. The growing burden raises concerns about long-term health risks, including type 2 diabetes, and highlights the need for healthier food environments, better nutrition and stronger school-based interventions.

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A young boy eating a slice of pepperoni pizza in front of a chain-link fence.
Children’s food environments and dietary habits are increasingly important in discussions about childhood obesity and long-term health risks.Image credit:Pexels

With more than 41 million Indian children and adolescents living with overweight or obesity, experts warn that unhealthy food environments could increase future risks of type 2 diabetes. New national guidance on childhood diabetes and proposed restrictions on junk food sales near schools highlight the need for preventive action.

As the world observes World Food Day on October 16, childhood nutrition is emerging as a challenge that extends beyond hunger and undernutrition. The growing prevalence of overweight and obesity among children is raising concerns about their long-term health, including their risk of developing type 2 diabetes.

India faces a particularly significant challenge. The World Obesity Atlas 2026 estimates that approximately 14.9 million children aged five to nine and 26.4 million children and adolescents aged 10–19 in India were living with overweight or obesity in 2025. Together, these figures amount to more than 41 million young people.

The report also estimates that around 1.39 million Indian children aged five to 19 had hyperglycaemia attributable to high body mass index in 2025. Hyperglycaemia refers to elevated blood glucose levels and is a health indicator associated with metabolic risk; it should not be interpreted as a count of children diagnosed with diabetes.

The figures highlight the importance of addressing childhood obesity early, before associated health risks become more difficult to manage.

Food environments and the risk of early-onset diabetes

The World Health Organization (WHO) reported in September 2026 that 400 million children and adolescents aged five to 19 worldwide were overweight in 2024, including 170 million living with obesity. The prevalence of overweight in this age group increased from 8% in 1990 to 20% in 2024.

Childhood obesity is influenced by a combination of biological, social, economic and environmental factors. Diets high in energy but low in essential nutrients, limited opportunities for physical activity and the easy availability of heavily marketed processed foods can contribute to unhealthy weight gain.

Obesity can increase insulin resistance, in which the body’s cells respond less effectively to insulin. This can raise the risk of type 2 diabetes, a condition that is increasingly important to consider in children and adolescents.

However, the relationship between food and diabetes requires an important distinction. Type 1 diabetes is an autoimmune condition in which the body’s immune system attacks insulin-producing cells in the pancreas. It is not caused by eating sugary foods or being overweight. Type 2 diabetes develops through different mechanisms and is associated with factors including excess body weight, genetics and physical inactivity.

The two conditions require different approaches to prevention and treatment.

India introduces a national childhood diabetes framework

In a significant policy development, the Union Ministry of Health and Family Welfare released a comprehensive guidance document on diabetes mellitus in children on May 3, 2026.

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Diabetic checkup.Representational image.Image credit:Pexels

The framework outlines a structured approach to screening, diagnosis, treatment and long-term management, linking community-level identification with district hospitals and medical colleges. It also provides for free-of-cost care at public health facilities, including insulin therapy, blood glucose monitoring supplies and follow-up services.

The guidance promotes awareness of the early warning signs of type 1 diabetes through the “4Ts”: Toilet, Thirsty, Tired and Thinner. These refer to frequent urination, excessive thirst, unusual tiredness and unexplained weight loss.

The initiative is important because timely diagnosis and access to insulin can be lifesaving for children with type 1 diabetes. It also highlights the need for health systems to identify and manage diabetes before complications develop.

Schools become a focus of food policy

India is also considering measures to improve the food environments surrounding schools. A Reuters report published on September 24, 2026, said the country was moving towards restrictions on the sale of foods high in fat, salt and sugar within a 50-metre radius of schools.

The proposed measures would affect vendors and shops selling products such as sugary drinks and packaged snacks near educational institutions. The proposal reflects growing concern about the availability of unhealthy foods in places where children spend much of their day.

If implemented effectively, school-focused measures could form part of a wider strategy that includes healthier school meals, accessible drinking water, nutrition education, physical activity and clearer food labelling.

However, restrictions alone cannot address the problem. Families also need affordable access to fruits, vegetables, pulses and other nutritious foods. Public-health measures must account for household budgets and the realities of food access in different communities.

Beyond calories

World Food Day 2026, themed “Innovate today. Nourish tomorrow,” offers an opportunity to reconsider what food security means for children. Access to sufficient calories is essential, but the nutritional quality of food also matters.

Reducing the future burden of type 2 diabetes requires action across healthcare, education, food policy and community environments. At the same time, children living with type 1 diabetes need timely diagnosis, uninterrupted insulin supplies and long-term medical support

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Why Some People Age Better Than Others May Be Written in Their Blood

A study links patterns in blood proteins and immune cells to long-term disease risk, offering new insights into why some people age more healthily than others.

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Healthcare professional holding an older adult’s hand during a medical consultation, illustrating research into healthy ageing and age-related health risks.
Researchers are exploring how blood protein patterns and immune system changes may help explain differences in healthy ageing and the risk of chronic diseases. Representational image. Image credit: Towfiqu barbhuiya/ Pexels

Ageing does not affect everyone in the same way. While some people remain relatively healthy into their later years, others develop several chronic illnesses despite being of a similar age. Scientists are investigating whether part of this difference can be traced to the way the immune system changes over a lifetime.

A study published in Immunity, offers a new clue. Researchers found that the balance between two populations of immune cells was associated with people’s long-term risk of disease and death. They also developed a way to estimate this balance using proteins circulating in the blood.

The findings could help scientists identify biological changes associated with unhealthy ageing before symptoms appear. Why do some people’s immune systems remain resilient while others develop patterns associated with declining health?

Ageing Leaves Marks on the Immune System

The immune system changes as people grow older. Its ability to respond to unfamiliar threats can weaken, while some immune cells become more prominent after years of exposure to infections and other stimuli. These changes can influence how the body responds to disease.

To investigate these differences, researchers examined approximately 12.4 million immune cells collected from 2,609 adults aged 20 to over 90 across eight study groups. Their analysis focused on two populations of T cells, which are white blood cells involved in identifying and responding to threats. The cells were distinguished by their production of granzyme K and granzyme B, proteins that help coordinate immune responses and destroy infected or abnormal cells.

The researchers found that older adults did not share a single pattern of immune ageing. Instead, their immune systems varied considerably, with some showing a greater presence of cells associated with granzyme B and others displaying a different balance.

That variation mattered when the team examined participants’ health outcomes. An immune profile dominated by granzyme B-producing cells was associated with a higher risk of several chronic conditions and death over the following years. The finding suggests that a person’s immune system may reveal aspects of their health trajectory that their age alone cannot capture.

What Blood Proteins Can Reveal

Counting specific immune cells requires specialised laboratory techniques. The researchers therefore investigated whether the proteins circulating in blood could offer an alternative way to estimate the same underlying pattern. They used a smaller dataset linking immune-cell measurements with blood-protein levels to develop a computer model. This model was then applied to data from approximately 50,000 participants in the UK Biobank, a long-running research resource that tracks health and biological information.

Microscopic illustration of immune cells against a red cellular background, representing research into immune ageing and blood protein signatures.
Immune-cell patterns and blood proteins helps to understand how changes in the immune system may be linked to healthy ageing and age-related disease risk. Representational image. Image credit: CDC/ Pexels

The team compared the predicted immune profiles with participants’ subsequent health records. Those whose profiles indicated a greater abundance of granzyme B-producing cells had higher risks of death and conditions including type 2 diabetes, hypertension, liver disease and kidney disease. The researchers followed health outcomes over an extended period, allowing them to investigate whether the blood-protein patterns were associated with future illness rather than simply reflecting differences observed at one point in time.

Could This Lead to an Early-warning Test?

One potential application is a blood test that helps identify people whose immune systems show signs associated with poorer long-term health. Many chronic diseases develop over years. Detecting biological changes before a person experiences noticeable symptoms could eventually give researchers and clinicians an additional way to assess risk and investigate preventive strategies.

The research team is working towards a simpler testing approach that could use standard laboratory equipment. At present, however, the findings represent a research advance rather than an established clinical test for healthy ageing. A useful test would need to do more than identify a statistical association. It would have to demonstrate that its predictions are sufficiently accurate for individual patients, work reliably across different populations and provide information that improves clinical decisions.

An Association That Needs Explanation

A greater abundance of granzyme B-producing cells could reflect underlying immune stress or other biological processes associated with disease. Researchers will need further investigation to establish whether these cells contribute directly to the development of chronic conditions or primarily act as indicators of changes occurring elsewhere in the body.

The results also require validation before the proposed protein signature can be used widely. A model developed from one set of participants may not perform equally well in people with different genetic backgrounds, lifestyles, environmental exposures or existing health conditions.

For ageing research, the larger opportunity lies in understanding why people follow different biological trajectories. A reliable marker could help scientists study these differences and identify when intervention might be most effective. The immediate achievement is a potential way to read some of those differences through blood. Whether that information can translate into longer, healthier lives will depend on the evidence that follows.

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