US flu activity shows another jump, first two peds deaths reported
United States flu activity jumped again the week ending Dec 18, with eight states reporting high or very high activity and the first two pediatric flu deaths reported for the season, the US Centers for Disease Control and Prevention (CDC) said today in its regular update.
Most flu markers showed steady rises, with eastern and central states seeing the biggest increases, with H3N2 as the dominant strain and infections continuing to affect a wider range of adult age groups after illnesses targeted younger people earlier in the season.
States or jurisdictions reporting high or very high activity—a marker that reflects clinic visits for flulike illness—include New Mexico, Kansas, North Dakota, Indiana, Tennessee, Georgia, New Jersey, and the District of Columbia. The CDC has said that other respiratory viruses are circulating and may be influencing flulike illness patterns.
Hospitalizations are starting to rise, and 1,265 people were admitted to the hospital for lab-confirmed flu during the week that ended Dec 18. Regarding the first two pediatric flu deaths of the season, one involved H3N2 and occurred during the week that ended on Dec 11. The other occurred the following week and was linked to unsubtyped influenza A.
The CDC also provided its first genetic flu virus characterization, noting that most H3N2 viruses are closely related to the vaccine strain, but there are some antigenic differences that are emerging as H3N2 viruses continue to evolve.
Dec 27 CDC FluView
Canada, Portugal, and Taiwan report H5 outbreaks in birds.
In the latest avian influenza developments, Canada reported a highly pathogenic H5N1 outbreak in captive birds at a multispecies exhibition farm on the island portion of New Foundland and Labrador, and Portugal reported more H5N1 in poultry.
The Canadian Food Inspection Agency confirmed H5N1 after the farm experienced sudden deaths of birds over several days. The event is considered a nonpoultry event, and the facility doesn't produce birds for sale.
Portugal's outbreak began on Dec 22 at a commercial turkey farm in Leiria region, killing 1,459 of 18,100 birds, according to a notification from the World Organization for Animal Health (OIE).
Elsewhere, Taiwan reported highly pathogenic H5N2 events in poultry and wild birds, according to separate notices from the OIE. There were nine poultry outbreaks, mostly at farms, but also at a slaughterhouse and at a site where discarded chickens were found. The outbreaks occurred at different locations in November and December, and taken together, the virus killed 2,755 of 66,408 susceptible birds. Taiwan also reported separate detections of H5N2 and H5N1 in wild birds.
Dec 22 CFIA statement
Dec 24 OIE report on H5N1 in Portugal
Dec 24 OIE report in H5N2 in Taiwanese poultry
Dec 24 OIE report on H5N2 in Taiwanese wild birds
Dec 23 OIE report on H5N1 in Taiwanese wild birds
In its latest avian influenza overview, the European Centre for Disease Prevention and Control (ECDC) said between Sep 18 and Dec 8, 27 European Union countries and the UK reported 867 highly pathogenic detections in poultry, wild, and captive birds. Italy had the most events in poultry, followed by Hungary and Poland.
It said the frequent incursions in poultry flocks raised concerns about biosecurity gaps. Genetic analysis shows that viruses belong to clade 18.104.22.168b. Tests suggest H5N1 viruses in Sweden, Germany, Poland, and the UK have been circulating in Europe since October 2020. However, viruses from North, Central, and East Europe show a novel reassortant that was introduced in October 2021.
Also, H5N1 was found in mammals in Sweden, Estonia, and Finland, and in some instances, the viruses have an adapative marker associated with increased virulence and replication in mammals.
Dec 22 ECDC report