University of Nebraska Medical Center

HPAI H5N1 (Avian Influenza)


Explore this page for HPAI H5N1 (Avian Influenza) information, updates/situational reports, news, webinars, and published papers. 


About HPAI H5N1

What is HPAI H5N1?

According to the Centers for Disease Control and Prevention (CDC), "Avian influenza or bird flu refers to the disease caused by infection with avian (bird) influenza (flu) Type A viruses. These viruses naturally spread among wild aquatic birds worldwide and can infect domestic poultry and other bird and animal species. Bird flu viruses do not normally infect humans. However, sporadic human infections with bird flu viruses have occurred."

The Highly Pathogenic Avian Influenza (HPAI) strain of the H5N1 avian flu is currently spreading in the U.S. and is the same as the one spreading in Europe and Asia. Both wild birds and domestic poultry have been affected, along with cases of the virus being found in wild mammals, such as foxes, mink, skunks, bears, sea lions, and otters. Few cases of H5N1 in cats have also been reported. Most recently in the spring of 2024, multiple US states reported infection of H5N1 in herds of dairy cows. Three cases have been reported in humans in the U.S. (1 in Colorado in 2022, 1 in Texas and 1 in Michigan in 2024). 

The CDC further explains "the wide geographic spread of A(H5N1) bird flu viruses in wild birds, poultry, and some other mammals, including in cows, is creating additional opportunities for people to be exposed to these viruses. Therefore, there could be an increase in sporadic human infections resulting from bird, cattle, and other animal exposures, even if the risk of these viruses spreading to people has not increased. Sporadic human infections in the current context would not significantly change CDC’s risk assessment." 

As of April 19, 2024, the CDC "is collaborating with partners including the U.S. Department of Agriculture (USDA), the Food and Drug Administration (FDA), and state public health and animal health officials to address this emerging infectious disease."

According to the World Health Organization,  on "May 23, 2024, the Mexico International Health Regulations (IHR) National Focal Point (NFP) reported to PAHO/WHO a confirmed fatal case of human infection with avian influenza A(H5N2) virus detected in a resident of the State of Mexico who was hospitalized in Mexico City. This is the first laboratory-confirmed human case of infection with an influenza A(H5N2) virus reported globally and the first avian H5 virus infection in a person reported in Mexico. Although the source of exposure to the virus in this case is currently unknown, A(H5N2) viruses have been reported in poultry in Mexico." 

Unofficial HPAI H5N1 Map
Unofficial HPAI H5N1 Map
Data was sourced and imported from FAO EMPRES, USDA APHIS, WAHIS, and open source news reports beginning in late 2022 to current.


Published Papers


Prosser, D.J., Teitelbaum, C.S., Yin, S. et al. Climate change impacts on bird migration and highly pathogenic avian influenza. Nat Microbiol 8, 2223–2225 (2023). https://doi.org/10.1038/s41564-023-01538-0
Vreman, S.; Kik, M.; Germeraad, E.; Heutink, R.; Harders, F.; Spierenburg, M.; Engelsma, M.; Rijks, J.; van den Brand, J.; Beerens, N. Zoonotic Mutation of Highly Pathogenic Avian Influenza H5N1 Virus Identified in the Brain of Multiple Wild Carnivore Species. Pathogens 202312, 168. https://doi.org/10.3390/pathogens12020168
Agüero MontserratMonne IsabellaSánchez AzucenaZecchin BiancaFusaro AliceRuano María Josédel Valle Arrojo ManuelFernández-Antonio RicardoSouto Antonio ManuelTordable PedroCañás JulioBonfante FrancescoGiussani EdoardoTerregino CalogeroOrejas Jesús Javier. Highly pathogenic avian influenza A(H5N1) virus infection in farmed minks, Spain, October 2022. Euro Surveill. 2023;28(3):pii=2300001. https://doi.org/10.2807/1560-7917.ES.2023.28.3.2300001
Learn about H5N2

A(H5N2) is one of several types of avian influenza (bird flu) viruses.

According to the CDC, "five subtypes of avian influenza A viruses are known to have caused human infections (H5, H6, H7, H9, and H10 viruses). The most frequently identified subtypes of avian influenza A viruses that have caused human infections are H5, H7 and H9 viruses. Specifically, A(H5N1) and A(H7N9) viruses have caused the majority of avian influenza A virus infections reported in people, with HPAI A(H5N6) and LPAI A(H9N2) viruses also causing human infections in recent years."

In June 2024, the World Health Organization reported the first fatality in a human caused by H5N2 in Mexico. 

Older H5N1 News