H5N1 and H9N2 antibodies detected in apparently healthy livestock in Egypt

A new study reports serologic evidence of avian influenza exposure in apparently healthy livestock in northern Egypt. Among 444 animals sampled between October 2024 and January 2026, H5N1 antibodies were detected in cattle and H9N2 antibodies in cattle, sheep and goats, suggesting repeated spillover from avian reservoirs into livestock.

Researchers sampled 444 apparently healthy adult animals from 33 small farms and mixed-species backyards in three northern Egyptian governorates to investigate exposure to avian influenza viruses circulating in poultry.

Serologic testing detected:

• 20 of 444 animals, or 4.5%, positive for H5N1 antibodies by hemagglutination inhibition

• 13 of 444, or 2.9%, positive by microneutralization

• 11 of 444, or 2.5%, positive for H9N2 antibodies.

H5N1 exposure detected only in cattle

All H5N1-seropositive animals were cattle. H5N1 antibodies were identified in two of the three governorates sampled, and small farms had a significantly higher proportion of positive cattle by microneutralization than backyard settings. The finding is notable because the animals showed no obvious clinical signs. However, seropositivity indicates previous exposure and does not demonstrate active infection, viral shedding or sustained cattle-to-cattle transmission.

H9N2 also detected in sheep and goats

H9N2 antibodies were found in several livestock species:

• 6 of 374 cattle

• 1 of 31 goats

• 4 of 39 sheep.

All positive H9N2 samples originated from three locations within the same governorate. This extends the evidence of avian influenza exposure beyond cattle and indicates that sheep and goats may also encounter poultry-associated influenza viruses in mixed farming environments.

A different context from the US dairy outbreak

Egypt provides a distinct epidemiological setting from the H5N1 outbreak in US dairy cattle. H5N1 clade 2.3.4.4b and H9N2 circulate widely in Egyptian poultry, including commercial farms, backyard flocks and live bird markets, creating repeated opportunities for cross-species exposure.

The H5N1 virus used in the study belonged to the EA-2021-AB genotype, which differs from the B3.13 genotype initially associated with US dairy cattle. This supports the idea that livestock susceptibility to H5N1 is not restricted to a single viral genotype.

Exposure does not prove sustained transmission

The study does not show that H5N1 or H9N2 are circulating autonomously in Egyptian livestock. No active infection was demonstrated, and the authors could not determine whether cattle develop the same mammary-gland tropism or high milk viral loads described in US dairy herds.

The findings instead document previous exposure to avian influenza viruses in livestock living in close contact with poultry.

Further RT-PCR, virus isolation and longitudinal sampling will be needed to determine how frequently these spillover events occur, whether they lead to productive infection and whether infected livestock can transmit the virus onward.