Study suggests onsite monitoring at buildings or complexes could aid efforts against disease spread
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In a new study, wastewater surveillance for multiple pathogens at five different sites—including an office and a museum—identified local trends that were not captured in larger surveillance programs, and some sites used the data to inform efforts to prevent disease spread. Jay Bullen of Untap Health in London, U.K., and colleagues present these findings in the open-access journal PLOS Global Public Health.
People with viral infections produce waste containing viral RNA that ends up in wastewater in sewage systems. Measuring viral RNA levels in wastewater at treatment plants can be a cost-effective way to monitor community health. For instance, this method has been useful for monitoring COVID-19 infection trends and tracking polio eradication efforts.
Prior research suggests that wastewater surveillance programs that track multiple diseases at once could be beneficial at the municipal level. However, few studies have assessed their potential value at smaller, site-specific scales.
To fill that gap, Bullen and colleagues monitored daily wastewater concentrations of multiple viruses at five different sites in the U.K.; an office, a charity center for elderly citizens, a museum, a university co-working space, and a care home. The community size of the sites ranged from 50 to 2,000 people, and the researchers measured wastewater levels of the viruses SARS-CoV-2, influenza A and B, RSV A and B, and norovirus GI and GII.
Analysis of trends captured in the wastewater measurements revealed links with site-specific reported events, including staff illness, cleaning practices, and holidays. At the care home, where the community had less contact with the larger regional community, wastewater data captured local events that were not seen in public health data. In larger, more open communities, such as the university space, wastewater data aligned more closely with public health data.
Some sites began using the wastewater data to help inform decisions about disease prevention efforts, such as enhanced cleaning routines and notices in bathrooms about washing hands with soap.
These findings suggest that near-source wastewater monitoring could benefit local communities and perhaps provide earlier warnings of wider trends. Further research is needed to refine understanding of these potential benefits.
The authors add: “Building-level wastewater surveillance enables detection of norovirus, influenza, RSV and COVID-19 in a local population not captured by national surveillance. We see a future with near-source wastewater surveillance scaled across different communities to provide tailored local infection prevention and control measures, reducing outbreaks.”
For centuries, it was believed that tuberculosis spread primarily when a vulnerable person spends hours in a poorly ventilated space with someone infectious. But new findings suggest that much TB transmission also occurs through casual contact.
Conventional thinking held that enclosed spaces such as households, prisons, and shelters, where people spent long periods of time together, were where most TB transmission took place. But new data suggest that casual contact at social settings like shopping malls, restaurants, bars, and places of worship also account for much TB transmission.
A recent study found that close contact explained only 9% of TB transmission links, while casual contact accounted for 49%. The study, called CONTEXT (Casual Contact and Migration in XDR TB), was conducted in KwaZulu-Natal.
The study’s lead author, Professor Neel Gandhi of Emory University in Atlanta, recently presented the findings at the Conference on Retroviruses and Opportunistic Infections (CROI) in San Francisco. The work has not yet been published in a peer-reviewed medical journal.
The new findings come in the context of other research (much of which was conducted in Cape Town) that suggest TB could be transmitted through breathing, and growing evidence that people with asymptomatic TB can transmit the infection.
Where transmission occurs
Gandhi tells Spotlight that TB transmission has traditionally been linked to prolonged, close contact, with previous studies showing that 9 to 30% of cases could be attributed to this type of contact. A compelling alternative argument, he says, is that the remaining 70% of transmission occurs due to casual contact in community settings – which is what their research sought to explore.
He elaborates: “For much of history, we have thought that most TB transmission occurs through close and prolonged contact, meaning that a susceptible person is spending a lot of time in a poorly ventilated area with somebody who is infectious. And so most often we think of households as places where transmission occurs; or congregate settings, places like prisons or homeless shelters.”
On defining casual contact, he says: “In our research, we wanted to understand less intense forms of contact where transmission can occur. So, we understood where people lived, but we also asked them where they spent time in a typical week. The phrase we used was: ‘where do you spend two hours or more, most weeks?’ To try to identify the places people spend substantial amounts of time; and seeing whether they crossed paths with somebody else to whom their molecular fingerprints (of their TB bacteria infection) match.”
Genotyping, and geomapping
In their study, Gandhi and his colleagues made use of both genotyping and geospatial mapping to figure out where TB transmission likely occurred.
Genotyping, explains Gandhi, is a technology developed about 30 years ago that allows us to examine the genetic code of TB bacteria, and to compare similarity between patients’ bacteria.
“TB is a bacteria that keeps its genetic code similar across many generations of replication. In layman’s terms, we call this molecular fingerprinting. If I were to transmit TB to somebody else; my TB bacteria and that person’s TB bacteria’s genetic codes would look very similar – almost identical – so we could use this fingerprinting technique by sequencing the genomes of the two TB bacteria to try to fully get a sense of what the likelihood of transmission was.”
Commenting on their geospatial methodology, he says: “When our participants told us where they live or where they spend time in the community, or where they get outpatient healthcare; our team went to those sites and captured a GPS coordinates.
“Just like we use GPS for mapping when we’re trying to get around town, we would get specific coordinates… If two people went to the same shop, they might have used different names for that shop, or let’s say they went to a shopping mall, they may have used different names for those places; but we used GPS coordinates allowing us to determine whether they were at the same place or close to one another. And we used the concept of proximity to try to understand the likelihood that they may have crossed paths.”
In the study they used the metric of “community proximity” defined as a radius of 500 metres, or less.
Gandhi illustrates the nuance of geomapping, using his university campus: “So the example I like to give is; I work in a building called the School of Public Health. Across the courtyard is the School of Nursing. If you just asked me, where do you work? I would tell you, I work in this building. If you ask the next person where they work, they may say, I work in the School of Nursing. That wouldn’t match up in terms of place name. But if we used a radius of 100 metres or 500 metres, we can determine that we work very close to one another. And there’s a cafe in yet another building that we may have eaten lunch in at the same time. TB being an airborne disease, I don’t have to sit next to that person or even to know that person; if I’m infectious, I could have transmitted to them if they were sitting and eating in the same room.”
Essentially, the researchers used genotyping, particularly molecular fingerprinting to help understand the likelihood of transmission between people who have drug resistant TB. And once individuals with similar molecular fingerprints were found, they used geomapping to see whether these patients could be connected through close contact – and if not close contact, then through casual contact.
He adds: “The most common place people told us were friends and family members’ homes. Then the next most common was places of shopping so shopping malls.”
At CROI, Gandhi responded to a question from a conference delegate around risk, saying that there appears to be a greater risk of TB transmission in social settings than previously understood.
Symptoms and disease
To Spotlight, he says more work is needed to understand why casual contact transmission is happening. “And it connects to another topic in the TB community that is gaining a lot of attention currently, which is trying to understand what the association is between symptoms and having TB disease,” says Gandhi.
He notes that the challenge for researchers moving forward is understanding the link between infectiousness and symptoms – specifically, understanding when a person becomes infectious, even if they show no symptoms.
Most TB public health interventions are still based on the assumption that people with TB will present at health facilities with classic TB symptoms such as persistent cough, night sweats, fever, weight loss, and chest pain. South Africa has however in recent years been offering TB tests to asymptomatic people thought to be at high risk of TB, as part of its targeted universal testing strategy.
“So you may have heard of this concept of what some people have called subclinical TB or asymptomatic TB. And that is to say, if you were to test a group of people who didn’t come to a health clinic, but let’s say you were on a street corner and you tested everybody who went by for TB, we’re coming to appreciate that as many as 50% of people may not either have any symptoms or may not have symptoms that are worrisome enough for them to seek healthcare, but are actually testing positive for TB disease,” Gandhi adds.
Gandhi says this reminds him of the early days of COVID-19, when scientists weren’t sure if people only became infectious after showing symptoms.
“Eventually we learned that people were infectious probably for a few days before they developed symptoms. And in the TB world, this may be an area we need to investigate. If there’s the possibility that somebody is infectious when they have absolutely no symptoms, they would go about their regular activities; going to work, going to school, going shopping, going to religious ceremonies, going to restaurants, and they may unknowingly be infectious with TB. So this is the challenge.”
The bigger picture
Commenting on the findings, Robert Wilkinson, Honorary Professor in the Department of Medicine at the University of Cape Town and director of the Centre for Infectious Diseases Research in Africa, says: “It is interesting, and the proportion of transmission estimated to occur outside the household is a low estimate, but not incompatible with other estimates.”
He notes that the phenomenon of transmission occurring after brief casual contact is not novel though, and has been investigated in previous studies.
Asked how the findings presented by Gandhi might affect the outlook on TB interventions, Wilkinson says: “Whilst close household exposure to infectious tuberculosis should prompt clinical evaluation especially if there are symptoms, finding a close contact by conventional contact tracing approaches is far from invariable. Therefore, in high incidence environments like South Africa more attention needs to be placed on mass radiographic (X-ray) and, or microbiological screening of asymptomatic persons.”
In a recent public lecture called ‘Hunting Bosons, Finding the Bummock’, Emeritus Professor in Medicine at the University of Cape Town, Robin Wood, former CEO of the Desmond Tutu Health Foundation, states: “I think we are changing the paradigm of tuberculosis.” He notes that research now targets “hidden reservoirs of TB transmission beyond visible, symptomatic cases… [as] TB silently spreads within communities through carriers who exhibit no symptoms yet contribute to transmission.” Asked about Gandhi’s findings, Wood told Spotlight he would reserve comment until the data is submitted for further peer review and publication.
Study details
The 305 respondents in the CONTEXT study were patients with extensively drug-resistant TB or pre-extensively drug-resistant TB. They were diagnosed between 2019 and 2022 in the eThekwini, Ilembe, Umgungundlovu, and Ugu regions. The average age was 36 years, with 137 (45%) women and 216 (73%) people living with HIV.
The study was conducted in collaboration with the Durban-based Centre for the AIDS Programme of Research in South Africa (CAPRISA).
“CAPRISA played a leadership role in conceptualising the science, development of the protocol and data collection instruments, oversight of all aspects of field work, including screening and enrolling patients, obtaining informed consent from patients or their proxy’s, field and laboratory data collection, data verification and data clean-up activities for all data used in this study,” says CAPRISA’s deputy director, Professor Kogieleum Naidoo.
CONTEXT was funded through the United States National Institutes of Health (NIH), the world’s largest health research funder which has in recent weeks terminated several grants in South Africa and elsewhere. “The funding period has ended,” says Gandhi. “Now we’re analysing all of the data, so it won’t be impacted by any changes happening at NIH.”
Brain implants hold immense promise for restoring function in patients with paralysis, epilepsy and other neurological disorders. But a team of researchers at Case Western Reserve University has discovered that bacteria can invade the brain after a medical device is implanted, contributing to inflammation and reducing the device’s long-term effectiveness.
The groundbreaking research, recently published in Nature Communications, could improve the long-term success of brain implants now that a target has been identified to address.
“Understanding the role of bacteria in implant performance and brain health could revolutionize how these devices are designed and maintained,” said Jeff Capadona, Case Western Reserve’s vice provost for innovation, the Donnell Institute Professor of Biomedical Engineering and senior research career scientist at the Louis Stokes Cleveland VA Medical Center.
Capadona’s lab led the study, which examined the presence of bacterial DNA in the brains of mouse models implanted with microelectrodes.
To their surprise, researchers found bacteria linked to the gut inside the brain. The discovery suggests that a breach in what is known as “the blood-brain barrier,” caused by implanting the device, could allow microbes to enter.
“This is a paradigm-shifting finding,” said George Hoeferlin, the study’s lead author, who was a biomedical engineering graduate student at Case Western Reserve in Capadona’s lab. “For decades, the field has focused on the body’s immune response to these implants, but our research now shows that bacteria—some originating from the gut—are also playing a role in the inflammation surrounding these devices.”
In the study, mouse models treated with antibiotics had reduced bacterial contamination and the performance of the implanted devices improved—although prolonged antibiotic use proved detrimental.
The discovery’s implications go beyond device failure. Some of the bacteria found in the brain have been linked to neurological diseases, including Alzheimer’s, Parkinson’s and stroke.
“If we’re not identifying or addressing this consequence of implantation, we could be causing more harm than we’re fixing,” Capadona said. “This finding highlights the urgent need to develop a permanent strategy for preventing bacterial invasion from implanted devices, rather than just managing inflammation after the fact. The more we understand about this process, the better we can design implants that work safely and effectively.”
Capadona said his lab is now expanding the research to examine bacteria in other types of brain implants, such as ventricular shunts used to treat hydrocephalus, an abnormal buildup of fluid in the brain.
The team also examined the faecal matter of a human subject implanted with a brain device and found similar results.
“This finding stresses the importance of understanding how bacterial invasion may not just be a laboratory phenomenon, but a clinically relevant issue,” said Bolu Ajiboye, professor in biomedical engineering at the Case School of Engineering and School of Medicine and scientist at the Cleveland VA Medical Center. “Through our strong translational pipeline between CWRU and the VA, we are now investigating how this discovery can directly contribute to safer, more effective neural implant strategies for patients.”
Streptococcus Pyrogenese bound To human neutrophil. Credit: NIH
A new study published in Nature Communications reveals a novel approach to mitigating tissue damage caused by Streptococcus pyogenes, the flesh-eating bacterium responsible for severe infections such as necrotising fasciitis. The research highlights how disrupting bacterial metabolism can help the body better tolerate infection and heal more effectively.
The study was led by Wei Xu, PhD, an assistant professor of biomedical sciences at the Marshall University Joan C. Edwards School of Medicine, and colleagues at Washington University School of Medicine and Central China Normal University. The team discovered that S. pyogenes manipulates the body’s immune response through its aerobic mixed-acid fermentation process, which produces metabolic byproducts, such as acetate and formate, that impair immune cell function, delay bacterial clearance and slow wound healing.
By inhibiting this bacterial metabolic pathway with a pyruvate dehydrogenase inhibitor, the team successfully reduced tissue damage in a mouse model of necrotising skin infection. These findings suggest that reprogramming bacterial metabolism could serve as a novel therapeutic approach, not only to improve host tolerance but also as a potential adjuvant therapy alongside antibiotics. This strategy could enhance the effectiveness of existing treatments, particularly in severe infections where antibiotic resistance or excessive inflammation worsens patient outcomes.
“This study sheds light on how bacterial metabolism influences the immune system,” Xu said. “By understanding these interactions, we can develop new treatment strategies that protect tissues, enhance antibiotic efficacy and improve patient outcomes.”
