Share on PinterestViruses remain stable when attached to waterborne microplastics, a new study shows. Image credit: Ole Spata/EyeEm/Getty Images.The researchers studied the stability of the viruses over time when suspended in water containing microplastics.They found that viruses can stick to microplastics and remain more stable than just in water. They note that more research is needed to understand how long pathogens can survive by attaching to microplastics.
Microplastics are plastic particles less than 5 millimeters (mm) in size. Once in the environment, they are quickly colonized by microorganisms.
Previous research suggests that human and animal pathogens can “hitchhike” on microplastics and thus spread to different areas.
Although wastewater treatment plants remove up to 99% of microplastics from wastewater, wastewater remains one of the main sources by which microplastics enter the environment.
This presents a risk of pathogens from human waste attaching to bacterial colonies known as biofilms on plastics.
Knowing whether pathogens found in microplastic biofilms remain infectious could help public health initiatives.
Researchers recently evaluated the stability of viruses when immersed in water containing microplastics.
They found that viruses attached to microplastic biofilms were more stable than when they were just in the water.
The study appears in Environmental Pollution.
For the study, the researchers tested two types of viruses. One, a bacteriophage, a virus that feeds on bacteria, known as Phi6, had an “envelope” or lipid layer around it similar to the flu virus, while the other, rotavirus strain SA11 (RV), did not. it had “wrapping”.
To begin, the researchers grew biofilms on 2-mm polyethylene microplastic pellets by inserting them into jars containing filtered lake water, unfiltered lake water, or water infused with nutrients to stimulate microbial growth for 7 to 14 days.
Biofilms formed in all three water treatments, although they formed more rapidly between the granules in the nutrient-based water source.
The biofilm-coated pellets were then inserted into flasks containing 100 milliliters (mL) of fresh lake water and 1 mL of Phi6 or SA11 rotavirus at concentrations typical of sewage samples.
To track the number of virus particles, the researchers removed samples of microplastics and 1 mL of water at 3, 24, and 48 hours.
After analyzing the samples, the researchers noticed that both Phi6 and RV particles had formed in the microplastics.
Although virus stability decreased over time, virus inactivation was lower in biofilm-colonized pellets than in water samples.
Furthermore, they noted that the RV viruses were more stable than the Phi6 viruses. This, they noted, demonstrates how the interaction between nonenveloped viruses and bacterial cell wall components can increase their infectivity and thermostability.
Dr. Nikolas Stasulli, an assistant professor in the Department of Biology and Environmental Sciences at the University of New Haven, who was not involved in the study, told Medical News Today, when asked how viruses might remain intact when hitchhiking with microplastics in fresh water:
“As the authors point out, much of the ability to ‘hitchhike’ in microplastics is due to the biofilm layer that bacteria form on microplastics. Once bacteria attach and adhere to the surface of microplastics, they can continue to recruit more bacteria through biofilm production, which acts like a biological glue that can help keep bacteria in close association with one another.” .
“During this process, other smaller things in the surrounding area, such as viruses or chemical compounds, can also attach to this biofilm. It is widely known that biofilm can protect bacteria enclosed in it from factors such as antibiotics and unfavorable environmental changes such as desiccation, so it could be that viruses attached to this biofilm get the same kind of protection against environmental changes. environments that can inactivate them. he added.
The study authors conclude that microplastic contamination is a potential pathway for viral spread and persistence in the environment.
When asked about the limitations of the study, Dr. Saif Uddin, a principal investigator at the Kuwait Institute for Scientific Research, who was not involved in the study, told MNT that the researchers did not sufficiently account for bioaerosols.
He noted that efforts to prevent cross-contamination are crucial, as higher microbial loads are transferred to microplastics in exhaled air.
He added that the researchers also did not investigate biofilms on dust or sand particles, which take less time to form on these materials than on plastics.
In addition, Dr. Stasulli noted that these are preliminary findings and more study is needed. He said that “[m]No doubt mineral studies will be conducted on a variety of viral human pathogens that will include variables such as route of infection and infective dose.”
“Combining future information on viral infectious dose and microplastic ingestion route, along with the variables discussed in this new study, will certainly help establish the impact that viruses in biofilm-coated microplastics may have on health.” human,” he continued.
Dr. Stasulli added that such research is nevertheless important for public health: “[As] are microscopic, these microplastic particles contaminated with human pathogens are easily ingested or inhaled by humans. The increased viability time on a surface that can easily enter the human body only increases the potential infection rate of these pathogens.”
However, Dr. Uddin noted that the risk of contracting a virus from microplastics is low compared to other routes of transmission due to the generally low concentrations of microplastics in water.
To put that in perspective, he noted that levels of microplastics in water typically range from 1 to 10 parts per cubic meter. Meanwhile, levels of phytoplankton, particulate matter, and zooplankton range from 1,000 to 100,000 per cubic meter.
Source: www.medicalnewstoday.com