Avian flu - Case definitions (suspected & probable) and state dashboards

[jackie-powers]

Currently, there are 3 avian flu dashboards at the state level that we have noted in our sources in addition to the CDC's national dashboard.

It appears that CA, WA, and the CDC are using standardized case definitions set by the Council of State and Territorial Epidemiologists (CSTE): https://cdn.ymaws.com/www.cste.org/resource/resmgr/position_statements_files_2023/24-ID-09_Novel_Influenza_A.pdf. It appears that confirmed cases are those that test positive at both the state- and CDC-level. Probable cases have tested positive at the state-level but negative during CDC's confirmatory testing.

Colorado: https://cdphe.colorado.gov/animal-related-diseases/hpai-h5n1
Colorado includes confirmed, presumptive, and number of people tested. Dashboard has not been updated since May 2024 as there have been no new cases. There is no information on case definitions.

California: https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/Bird-Flu.aspx
California's dashboard only includes confirmed cases. However, there is a footnote that lists the number of probable cases according to CSTE. This is the number of cases that have tested positive by a local lab, but confirmatory testing by CDC was negative. It is unclear whether probable cases are included in the confirmed count. Will need to crosscheck with CDC's table.

Washington: https://doh.wa.gov/you-and-your-family/illness-and-disease-z/avian-influenza
Washington's dashboard includes the confirmed, probable, and total case counts in addition to the exposure (poultry, bovine, other). For their case definitions it says: "Total human cases include both confirmed and probable cases of novel influenza A. Human cases by classification show which of the total cases have been classified as confirmed or probable.* *Updates to national public health reporting and notification of novel influenza A infections were approved by the Council of State and Territorial Epidemiologists (CSTE) in June 2024 and enacted in September 2024. Whether a case is counted as confirmed or probable is determined after completion of a public health case investigation and takes into account a person's exposure to avian influenza virus, whether confirmatory testing at the CDC was negative or positive, and whether a person experienced symptoms of illness. The specific criteria used to determine if a case is confirmed, or probable is based on a standardized case definition for public health surveillance which allows states to apply the same criteria and to count cases in the same manner for national reporting."
It is unclear whether the probable cases include ones that were negative by CDC testing.

[jackie-powers]

11/5/24: Both CA dashboard and CDC dashboard are at 20 cases. Therefore, it does not appear that CA's total counts include the probable case.

[jackie-powers]

11/5/24: CDC counts do not include probable cases: "Not included in that count are four probable cases -- one in a California dairy farm worker and three in Washington state poultry farm workers. While these probable cases were negative on confirmatory testing at CDC, all four met the Council of State and Territorial Epidemiologists (CSTE) probable case definition (https://cdn.ymaws.com/www.cste.org/resource/resmgr/position_statements_files_2023/24-ID-09_Novel_Influenza_A.pdf) and have been reported by the states." https://www.cdc.gov/bird-flu/spotlights/h5n1-response-11012024.html CA and CDC counts match, so CA's total counts do not include probable cases.