A: Hey there! Heard anything interesting lately?
B: Not much, just work and stuff. What's up?
A: So, remember that bird flu thing going around the US dairy farms?
B: Uh-huh, yeah...
A: Well, a group of researchers is saying the delay in treatment might make it drug-resistant!
B: Oh no! Who's leading this study?
A: It's Professor Kawaoka from the University of Tokyo. He's been studying this H5N1 virus since early 2024.
B: Wow, that sounds serious... Any reports about human cases?
A: Yes, apparently there have been 41 cases where it seems to be transmitted from cows to humans.
B: Whoa! That's a lot! What did they do with the antiviral drug Xofluza?
A: They gave it to mice infected with bovine H5N1 virus and saw its effectiveness. Unfortunately, it didn't work so well when given late.
B: What do you mean?
A: Well, if they gave the drug 24 hours after infection, three out of five mice died, and a Xofluza-resistant virus was found in one of them.
B: And if they waited 48 hours...?
A: They all died, with three having drug-resistant viruses. But when given right after infection, none died, and no drug-resistant viruses were found.
B: So, it's better to treat early! What does Professor Kawaoka suggest?
A: He thinks the virus multiplies so quickly that drug resistance might occur easily. He recommends looking into extending treatment periods and increasing dosage if humans get infected.
----------------
A group of researchers says delayed treatment of a type of bird flu now spreading on dairy farms in the United States may increase the virus's drug-resistance.
The group is led by Professor Kawaoka Yoshihiro of the University of Tokyo Pandemic Preparedness, Infection and Advanced Research Center.
It has been studying the highly pathogenic H5N1 avian influenza virus that has spread rapidly among US dairy cattle since early 2024.
There have been reports that the virus appears to have been transmitted from cows to humans in 41 cases.
The researchers gave the antiviral drug Xofluza, or baloxavir marboxil, to mice infected with bovine H5N1 virus and examined its efficacy.
They say that of the five mice treated with Xofluza from 24 hours after infection, three died within 21 days. They say a Xofluza-resistant virus was found in one dead mouse.
The researchers say all five mice that were given Xofluza from 48 hours after infection died. Three of them reportedly had drug-resistant viruses.
But the group says none of the mice given the drug starting one hour after infection died, and no drug-resistant viruses were found in them.
Professor Kawaoka says there is a possibility that the virus multiplies so quickly that the emergence of drug-resistance might be facilitated.
He says there is need to explore ways to respond, such as extending the period of drug administration and increasing dosage, in case humans are infected.
B: Not much, just work and stuff. What's up?
A: So, remember that bird flu thing going around the US dairy farms?
B: Uh-huh, yeah...
A: Well, a group of researchers is saying the delay in treatment might make it drug-resistant!
B: Oh no! Who's leading this study?
A: It's Professor Kawaoka from the University of Tokyo. He's been studying this H5N1 virus since early 2024.
B: Wow, that sounds serious... Any reports about human cases?
A: Yes, apparently there have been 41 cases where it seems to be transmitted from cows to humans.
B: Whoa! That's a lot! What did they do with the antiviral drug Xofluza?
A: They gave it to mice infected with bovine H5N1 virus and saw its effectiveness. Unfortunately, it didn't work so well when given late.
B: What do you mean?
A: Well, if they gave the drug 24 hours after infection, three out of five mice died, and a Xofluza-resistant virus was found in one of them.
B: And if they waited 48 hours...?
A: They all died, with three having drug-resistant viruses. But when given right after infection, none died, and no drug-resistant viruses were found.
B: So, it's better to treat early! What does Professor Kawaoka suggest?
A: He thinks the virus multiplies so quickly that drug resistance might occur easily. He recommends looking into extending treatment periods and increasing dosage if humans get infected.
----------------
A group of researchers says delayed treatment of a type of bird flu now spreading on dairy farms in the United States may increase the virus's drug-resistance.
The group is led by Professor Kawaoka Yoshihiro of the University of Tokyo Pandemic Preparedness, Infection and Advanced Research Center.
It has been studying the highly pathogenic H5N1 avian influenza virus that has spread rapidly among US dairy cattle since early 2024.
There have been reports that the virus appears to have been transmitted from cows to humans in 41 cases.
The researchers gave the antiviral drug Xofluza, or baloxavir marboxil, to mice infected with bovine H5N1 virus and examined its efficacy.
They say that of the five mice treated with Xofluza from 24 hours after infection, three died within 21 days. They say a Xofluza-resistant virus was found in one dead mouse.
The researchers say all five mice that were given Xofluza from 48 hours after infection died. Three of them reportedly had drug-resistant viruses.
But the group says none of the mice given the drug starting one hour after infection died, and no drug-resistant viruses were found in them.
Professor Kawaoka says there is a possibility that the virus multiplies so quickly that the emergence of drug-resistance might be facilitated.
He says there is need to explore ways to respond, such as extending the period of drug administration and increasing dosage, in case humans are infected.
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Summary
Researchers led by Professor Kawaoka at the University of Tokyo are warning about drug-resistant bird flu, specifically H5N1, on US dairy farms. Delayed treatment might increase resistance to Xofluza, an antiviral drug. The study shows that if given late, the drug was ineffective and could even
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ID: 88a2fef5-9fe3-4fb6-815a-55e5c3d60e42
Category ID: nhk
URL: https://www3.nhk.or.jp/nhkworld/en/news/20250721_06/
Date: July 21, 2025
Created: 2025/07/21 19:00
Updated: 2025/12/08 03:17
Last Read: 2025/07/21 20:03