Influenza A(H5N1) detection in two asymptomatic poultry farm workers in Spain, September to October 2022: suspected environmental contamination

• Published in: Euro surveillance : bulletin européen sur les maladies transmissibles Vol. 28; no. 8; p. 1
• Main Authors: Aznar, Esteban, Casas, Inmaculada, González Praetorius, Alejandro, Ruano Ramos, María José, Pozo, Francisco, Sierra Moros, María José, García Rivera, María Victoria, Sánchez Sánchez, Azucena, García Villacieros, Elena, Saravia, Gabriela, Iglesias-Caballero, María, Román Marcos, Elena, García San Miguel, Lucía
• Format: Journal Article
• Language: English
• Published: Sweden Centre Europeen pour la Surveillance Epidemiologique du SIDA (European Centre for the Epidemiological Monitoring of AIDS) 23-02-2023; European Centre for Disease Prevention and Control (ECDC)
• Subjects: Animals; Asymptomatic; Avian flu; Disease Outbreaks - veterinary; Epidemics; Farmers; Farms; Humans; Influenza A Virus, H5N1 Subtype; Influenza in Birds - diagnosis; Influenza in Birds - epidemiology; Influenza, Human - diagnosis; Influenza, Human - epidemiology; Livestock industry; Poultry; Poultry Diseases - epidemiology; Rapid Communication; Serology; Spain - epidemiology; Workers; Spain; highly pathogenic avian influenza; outbreak; human; HPAI A(H5N1); asymptomatic; Spain
• ISSN: 1560-7917; 1025-496X; 1560-7917
• DOI: 10.2807/1560-7917.es.2023.28.8.2300107

In autumn 2022, the Spanish Influenza National Reference Laboratory (NRL) confirmed the detection of influenza A(H5N1) in samples from two asymptomatic workers linked to an outbreak in a poultry farm in Spain. Nasopharyngeal swabs were taken according to a national screening protocol for exposed workers. Absence of symptoms, low viral load and negative serology in both workers suggested environmental contamination. These findings motivated an update of the early detection strategy specifying timing and sampling conditions in asymptomatic exposed persons.