Nikhil Prasad Fact checked by:Thailand Medical News Team May 03, 2026 1 hour, 33 minutes ago
Medical News: A widely used anti-parasitic drug may soon find a new role in combating some of the world’s most dangerous influenza viruses, according to a new study that is drawing increasing attention among scientists and public health experts.
Existing anti-parasitic drug shows promise against bird flu strains
Rising Concerns Over Deadly Bird Flu Strains
Highly pathogenic avian influenza viruses, known as H5Nx strains, have been spreading among birds globally and have occasionally infected humans. Although such infections are rare, they are often severe and can be fatal. A major concern is that these viruses mutate rapidly, allowing them to develop resistance to current antiviral drugs.
Most existing influenza treatments are designed to attack the virus directly. However, when the virus changes, these drugs can become less effective. This has prompted researchers to explore alternative approaches that do not rely solely on targeting the virus.
Repurposing an Existing Drug
In the latest research, scientists investigated niclosamide, a drug long used to treat parasitic worm infections. Instead of targeting the virus itself, niclosamide works by disrupting processes within human cells that viruses depend on to replicate.
The study was conducted by researchers from The University of Tokyo’s Pandemic Preparedness, Infection and Advanced Research Center (UTOPIA), the Division of Virology at the Institute of Medical Science at the University of Tokyo, the Influenza Research Institute at the University of Wisconsin-Madison in the United States, and The Research Center for Global Viral Diseases at the National Institute of Global Health and Medicine, Japan Institute for Health Security.
Strong Laboratory Evidence Across Multiple Virus Types
Researchers tested niclosamide against four different H5Nx virus strains derived from human infections between 2020 and 2023. These included strains of H5N1, H5N6, and H5N8.
The results showed that niclosamide effectively blocked viral replication in laboratory cell cultures at relatively low concentrations. Notably, the drug demonstrated stronger activity than favipiravir, a commonly used antiviral medication.
Importantly, the drug showed minimal toxicity to healthy cells at effective doses, suggesting it may be safe within a controlled therapeutic range.
Effective in Human Lung Cell Models
Further testing was conducted using human lung cells, which are the primary targets of severe influenza infections. Niclosamide significantly reduced viral levels in these cells, lowering virus counts by as much as 1,000-fold within 48 hours.
This finding highlights the drug’s potential relevance in real-world infections affecting the respiratory system.
Evidence From Animal Studies
The research also included animal experiments involving mice infected with a lethal dose of H5N1 virus. While untreated mice experienced severe illness and high mortality, approximately 40 percent of mice treated with niclosamide survived.
Althoug
h not fully protective, this level of effectiveness is considered promising given the severity of the infection.
Activity Against Drug Resistant Variants
A key strength of niclosamide identified in the study is its ability to remain effective against virus strains that have developed resistance to existing antiviral drugs such as baloxavir and favipiravir.
Because niclosamide targets host cell mechanisms rather than viral components, the virus is less able to develop resistance. This makes it a potentially valuable option in managing emerging and evolving influenza threats.
Potential Role in Combination Therapy
The study also explored the use of niclosamide alongside established antiviral medications. While the combination did not significantly enhance effectiveness, it did not reduce the activity of either drug.
This suggests that niclosamide could be safely incorporated into existing treatment regimens. This
Medical News report underscores the importance of combination strategies in addressing complex viral infections.
Challenges and Future Directions
Despite its promise, niclosamide faces several challenges. It has limited absorption when taken orally and may cause side effects at higher doses. Researchers are currently exploring alternative delivery methods, including nasal sprays and inhaled formulations, to improve its effectiveness and safety.
Conclusion
The findings from this study provide compelling early evidence that niclosamide may serve as a useful therapeutic option against highly pathogenic avian influenza viruses, including strains resistant to current antiviral drugs. By targeting host cell processes rather than the virus itself, niclosamide offers a different and potentially more resilient approach to treatment. However, further clinical research is essential to confirm its safety and effectiveness in humans and to optimize delivery methods. If these challenges are successfully addressed, niclosamide could become an important component of future strategies to combat influenza outbreaks and reduce the global risk of pandemics.
The study findings were published in the peer reviewed journal: Antiviral Research.
https://www.sciencedirect.com/science/article/pii/S016635422600080X
For the latest on H5Nx Avian viruses, keep on logging to Thailand
Medical News.
Read Also:
https://www.thailandmedical.news/articles/h5n1-avian-flu
Medical Disclaimer: All content published by Thailand Medical News is based on scientific research and is intended for informational and educational purposes only. It is not medical advice, diagnosis, or treatment. Readers must not attempt to use, apply, or experiment with any protocols, compounds, or therapies mentioned without first consulting a qualified and licensed medical doctor. Many findings discussed are experimental or preliminary, and only a licensed healthcare professional can determine what is safe and appropriate for an individual’s specific medical condition.
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