Human Cases of Highly Pathogenic Avian Influenza A<b>(</b>H5N1<b>)</b> — California, September–December 2024
Persons who work closely with dairy cows, poultry, or other animals with suspected or confirmed infection with highly pathogenic avian influenza (HPAI) A(H5N1) viruses are at increased risk for infection. In September 2024, the California Department of Public Health was notified of the first human case of HPAI A(H5N1) in California through monitoring of workers on farms with infected cows. During September 30-December 24, 2024, a total of 38 persons received positive test results for HPAI A(H5N1) viruses in California; 37 were dairy farm workers with occupational exposure to sick cows, and one was a child aged <18 years with an undetermined exposure, the first pediatric HPAI A(H5N1) case reported in the United States. All patients had mild illness. The identification of cases associated with occupational exposure to HPAI A(H5N1) viruses on dairy farms highlights the continued risk for persons who work with infected animals. The pediatric case was identified through routine surveillance. Given recent increases in the prevalence of HPAI A(H5N1) viruses among some animal populations, public health agencies should continue to investigate cases of HPAI A(H5N1) in humans as part of control measures, pandemic preparedness, to identify concerning genetic changes, and to prevent and detect potential human-to-human transmission of the virus. To date, no human-to-human transmission of HPAI A(H5N1) virus has been identified in the United States.
Authors
- Erica Pan (ORCID: https://orcid.org/0000-0001-5118-4389)
- Bárbara Silva Gonzaga (ORCID: https://orcid.org/0000-0001-6271-1535)
- Cora Hoover
- Annabelle de St. Maurice (ORCID: https://orcid.org/0000-0001-7368-7403)
- Elizabeth Traub
- Estela Saguar
- Christina Morales (ORCID: https://orcid.org/0000-0001-5813-7219)
- Dominique Lemoine
- C. Todd Davis (ORCID: https://orcid.org/0000-0002-7075-7477)
- Y. Chang
- Allison Joyce
- Jocelyn San Mateo
- Brandon Brown (ORCID: https://orcid.org/0000-0002-6348-4108)
- Nicholas Moss
- Vit Kraushaar (ORCID: https://orcid.org/0009-0009-6796-8263)
- Aisha Masood
- Denise Lopez
- James Locke (ORCID: https://orcid.org/0000-0003-0670-1943)
- Erin L. Murray (ORCID: https://orcid.org/0000-0002-6674-4868)
- Krista Kniss (ORCID: https://orcid.org/0000-0001-8464-4599)
- Kyoo Shim
- Sophie Zhu (ORCID: https://orcid.org/0000-0002-8694-4058)
- Chao‐Yang Pan (ORCID: https://orcid.org/0000-0003-1584-4233)
- Kavita K. Trivedi (ORCID: https://orcid.org/0000-0001-7538-684X)
- Simon Paul (ORCID: https://orcid.org/0000-0002-2909-0965)
- Jade A. Herrera
- Rebecca Campagna
- Nicole Green (ORCID: https://orcid.org/0000-0002-0371-0986)
- María Cristina Rangel (ORCID: https://orcid.org/0000-0002-8002-9617)
- Alice P. Chen (ORCID: https://orcid.org/0000-0002-1426-853X)
- Kathleen Harriman (ORCID: https://orcid.org/0000-0003-2416-9663)
- Alejandro E. Macías (ORCID: https://orcid.org/0000-0002-6573-4350)
- Shiffen Getabecha
- Krupa Pattni
- Rina Ramírez (ORCID: https://orcid.org/0000-0003-1924-5844)
- April Hatada
- Sharon I. Brummitt (ORCID: https://orcid.org/0000-0001-7905-7592)
- Minhphuong Nguyen
- María Salas (ORCID: https://orcid.org/0000-0002-0583-9492)
- C B Liu
- Esmeralda Íñiguez-Stevens
- Marie K. Kirby (ORCID: https://orcid.org/0000-0003-0859-9604)
- Heidi Ransohoff
- Kyle M. Hernandez (ORCID: https://orcid.org/0000-0001-8267-644X)
- O. Lima Gomez
- Katya Ledin
- Jennifer McNary
- Nina J. Gao (ORCID: https://orcid.org/0000-0003-4314-3805)
- Carlos Luna (ORCID: https://orcid.org/0000-0002-0149-9814)
- Blanca Molinar
- Debra A. Wadford (ORCID: https://orcid.org/0000-0002-8630-427X)
- Hugo Guevara (ORCID: https://orcid.org/0009-0001-7856-4223)
- Kurt O. Reinhart (ORCID: https://orcid.org/0000-0002-7985-6738)
- Holly Howard
- Cindy Wong
- Sergio Sanchez (ORCID: https://orcid.org/0000-0001-7761-0067)
- Chelsea L. Wright
- Tasha Padilla
- Jesse Elder
- John L. Bell (ORCID: https://orcid.org/0009-0000-4236-2497)
- James D. Heffelfinger
- Anthony Tran
- Jeffrey M. Schapiro
- Rahil Ryder
- Carol Glaser
- Jahara Cayabyab
- Brandon Stavig
- Hamed Gharibi
- Laura Esbenshade
- Paula Ptomey
- Paul Rzucidlo
- Thea Papasozomenos
- Payeng Moua
- Eric El-Tobgy
- Cristin Mondy
- Taylor Mundt
- Matthew Bacinskas
- Cynthia Bernas
- Ydelita Gonzales
- Sergio Martinez-Paredes
- Kao Saechao
- Jocelyn Limas
- Ioana Seritan
- Kathleen Garvey
Publication Details
- Journal
- MMWR Morbidity and Mortality Weekly Report
- Published
- 2025-03-13
- DOI
- https://doi.org/10.15585/mmwr.mm7408a1
- Citations
- 18
- Primary Topic
- Influenza Virus Research Studies
- Type
- article
- Field-Weighted Citation Impact
- 24.38