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Study Raises Questions About Key Features of H5N1 Infection in Cattle
— It may not always produce mild illness, and asymptomatic animals can harbor virus
by Kristina Fiore, Director of Enterprise & Investigative Reporting, MedPage Today,
July 26, 2024
A new paper challenged two ideas about how the H5N1 bird flu behaves in cattle: that it always produces mild illness, and that asymptomatic animals don't spread disease.
Instead, the paper showed that cattle mortality was twice as high during outbreaks on two of the nine farms assessed, and almost a third of nasal swabs in asymptomatic animals were positive for the virus, as were half of urine samples.
The findings underscore "the need for robust measures to prevent and control the infection and further spread of HPAI [highly pathogenic avian influenza] H5N1 in dairy cattle," Kiril Dimitrov, DVM, PhD, of Texas A&M Veterinary Medical Diagnostic Laboratory in College Station, and co-authors wrote in Natureopens in a new tab or window. "This would reduce the risk of the virus adapting in this new mammalian host species, thereby decreasing the pandemic risk to humans."
Dimitrov and colleagues studied nine farms -- five in Texas, two in New Mexico, one in Kansas, and one in Ohio -- that had outbreaks from February 11 to March 19.
The New York Times reportedopens in a new tab or window that 99 cows died during a 3-week outbreak on the Ohio farm, which is twice the normal mortality rate. The other increased mortality event occurred on a Texas farm, according to the paper.
The researchers found evidence of subclinical infection in some cows, with viral RNA detected in six of 19 nasal swabs and four of eight urine samples. Interestingly, animals with clinical illness shed virus at a lower frequency in nasal swabs and urine, they noted…..
lots more :tiphat:
https://www.medpagetoday.com/infectiousdisease/uritheflu/111256
— It may not always produce mild illness, and asymptomatic animals can harbor virus
by Kristina Fiore, Director of Enterprise & Investigative Reporting, MedPage Today,
July 26, 2024
A new paper challenged two ideas about how the H5N1 bird flu behaves in cattle: that it always produces mild illness, and that asymptomatic animals don't spread disease.
Instead, the paper showed that cattle mortality was twice as high during outbreaks on two of the nine farms assessed, and almost a third of nasal swabs in asymptomatic animals were positive for the virus, as were half of urine samples.
The findings underscore "the need for robust measures to prevent and control the infection and further spread of HPAI [highly pathogenic avian influenza] H5N1 in dairy cattle," Kiril Dimitrov, DVM, PhD, of Texas A&M Veterinary Medical Diagnostic Laboratory in College Station, and co-authors wrote in Natureopens in a new tab or window. "This would reduce the risk of the virus adapting in this new mammalian host species, thereby decreasing the pandemic risk to humans."
Dimitrov and colleagues studied nine farms -- five in Texas, two in New Mexico, one in Kansas, and one in Ohio -- that had outbreaks from February 11 to March 19.
The New York Times reportedopens in a new tab or window that 99 cows died during a 3-week outbreak on the Ohio farm, which is twice the normal mortality rate. The other increased mortality event occurred on a Texas farm, according to the paper.
The researchers found evidence of subclinical infection in some cows, with viral RNA detected in six of 19 nasal swabs and four of eight urine samples. Interestingly, animals with clinical illness shed virus at a lower frequency in nasal swabs and urine, they noted…..
lots more :tiphat:
https://www.medpagetoday.com/infectiousdisease/uritheflu/111256