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

Aznar, E. Vicente; Casas, Inmaculada; Praetorius, Alejandro González; Ramos, María José Ruano; Pozo, Francisco; Moros, María José Sierra; Rivera, María Victoria García; Sánchez, Azucena; Villacieros, Elena García; Saravia, Gabriela; Iglesias-Caballero, María; Marcos, Elena Román; Miguel, Lucía García San

doi:10.2807/1560-7917.es.2023.28.8.2300107

Cited by 13 publications

(9 citation statements)

References 4 publications

(3 reference statements)

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“…However, due to low virus load no full genome could be generated and no seroconversion was present in the workers. This indicates rather a contamination of the mucosa with avian influenza viruses due to exposure to highly contaminated environment despite wearing personal protective equipment (PPE) and not a systemic infection (Aznar et al, 2023) (ECDC, 2022aSanidad, 2022;WHO, online-a). Other farm workers involved in the culling activities during the outbreak at the same farm tested negative.…”

Section: Most Recent Human Infections With Avian Influenza A(h5n1) An...mentioning

confidence: 99%

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Avian influenza overview December 2022 – March 2023

Adlhoch¹,

Fusaro²,

Gonzáles³

et al. 2023

EFS2

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Between 3 December 2022 and 1 March 2023 highly pathogenic avian influenza (HPAI) A(H5N1) virus, clade 2.3.4.4b, was reported in Europe in domestic (522) and wild (1,138) birds over 24 countries. An unexpected number of HPAI virus detections in sea birds were observed, mainly in gull species and particularly in black-headed gulls (large mortality events were observed in France, Belgium, the Netherlands, and Italy). The close genetic relationship among viruses collected from black-headed gulls suggests a southward spread of the virus. Moreover, the genetic analyses indicate that the virus persisted in Europe in residential wild birds during and after the summer months. Although the virus retained a preferential binding for avian-like receptors, several mutations associated to increased zoonotic potential were detected. The risk of HPAI virus infection for poultry due to the virus circulating in black-headed gulls and other gull species might increase during the coming months, as breeding bird colonies move inland with possible overlap with poultry production areas. Worldwide, HPAI A(H5N1) virus continued to spread southward in the Americas, from Mexico to southern Chile. The Peruvian pelican was the most frequently reported infected species with thousands of deaths being reported. The reporting of HPAI A(H5N1) in mammals also continued probably linked to feeding on infected wild birds. In Peru, a mass mortality event of sea lions was observed in January and February 2023. Since October 2022, six A(H5N1) detections in humans were reported from Cambodia (a family cluster with 2 people, clade 2.3.2.1c), China (2, clade 2.3.4.4b), Ecuador (1, clade 2.3.4.4b), and Vietnam (1, unspecified clade), as well as two A(H5N6) human infections from China. The risk of infection with currently circulating avian H5 influenza viruses of clade 2.3.4.4b in Europe is assessed as low for the general population in the EU/EEA, and low to moderate for occupationally or otherwise exposed people.

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Section: Most Recent Human Infections With Avian Influenza A(h5n1) An...mentioning

confidence: 99%

“…Source:(Pyankova et al, 2021; WHO, 2021a, c;Oliver et al, 2022; WHO, 2022b;Aznar et al, 2023; CDC, online-c; ECDC, online; WHO, online-c) …”

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confidence: 99%

Avian influenza overview December 2022 – March 2023

Adlhoch¹,

Fusaro²,

Gonzáles³

et al. 2023

EFS2

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“…The United Kingdom also reported such cases. On further investigation, all but one were considered most likely to be from mucosal contamination through environmental exposure rather than infection, and the remaining one was inconclusive (Aznar et al., 2023 ; UKHSA, 2024 ; WHO, 2024a ).…”

Section: Current Situationmentioning

confidence: 99%

Drivers for a pandemic due to avian influenza and options for One Health mitigation measures

Melidou,

Enkirch,

Willgert

et al. 2024

EFS2

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Avian influenza viruses (AIV) remain prevalent among wild bird populations in the European Union and European Economic Area (EU/EEA), leading to significant illness and mortality of birds. Transmission between bird and mammal species has been observed, particularly in fur animal farms, where outbreaks have been reported. While transmission from infected birds to humans is rare, there have been instances of exposure to these viruses since 2020 without any symptomatic infections reported in the EU/EEA. However, these viruses continue to evolve globally, and with the migration of wild birds, new strains carrying potential mutations for mammalian adaptation could be selected. If avian A(H5N1) influenza viruses acquire the ability to spread efficiently among humans, large-scale transmission could occur due to the lack of immune defences against H5 viruses in humans. The emergence of AIV capable of infecting mammals, including humans, can be facilitated by various drivers. Some intrinsic drivers are related to virus characteristics or host susceptibility. Other drivers are extrinsic and may increase exposure of mammals and humans to AIV thereby stimulating mutation and adaptation to mammals. Extrinsic drivers include the ecology of domestic and wild host species, human activities like farming practices and the use of natural resources, climatic and environmental factors. One Health measures to mitigate the risk of AIV adapting to mammals and humans focus on limiting exposure and preventing spread. Key options for actions include enhancing surveillance targeting humans and animals, ensuring access to rapid diagnostics, promoting collaboration between animal and human sectors, and considering the implementation of preventive measures such as vaccination of poultry. Effective communication to different target audiences should be emphasised, as well as strengthening veterinary infrastructure, enforcing biosecurity measures at farms, and reducing wildlife contact with domestic animals. Careful planning of poultry and fur animal farming, especially in areas with high waterfowl density, is essential for effective risk reduction.

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“…To the Editor: Following the infection event of highly pathogenic avian influenza (HPAI) A(H5N1) in farmed minks [1], poultry farms were also reported as affected by the same virus in Spain from October 2022 [2]. The virus contains a second sialic acid binding site in neuraminidase [3].…”

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confidence: 99%

“…To our knowledge, it is the first time that outbreaks of HPAI A(H5N1) have occurred within the same season not only in wild birds and poultry but also in several mammalian species in various geographical locations. As Aznar et al noted, it is unusual for bird-to-human transmission to occur frequently [2], and person-toperson transmission of HPAI A(H5N1) has been limited [4]. In light of these conventional understandings, we may have to focus on two possible pathways that could potentially lead to a pandemic in humans, i.e.…”

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confidence: 99%