#Outbreak of #H9N2 avian #influenza viruses in lesser #rhea in #Peru, June-July 2025

 

Abstract

Avian influenza viruses (AIVs) are endemic in the Americas and responsible for outbreaks in both domestic and wild birds that occasionally spill over into humans. We report the first known outbreak of AIV H9N2 in lesser rhea (Rhea pennata), also known as Darwin’s rhea, in the region of Puno-Peru. The animals in this study lived in an isolated conservation center located in remote highlands above 4,000 m.a.s.l. Between June and July 2025, a total of 46/92 animals were recorded sick, with symptoms including greenish diarrhea (100%), hyporexia (24%), dyspnea (76%), nasal discharge (42%), drowsiness (18%) and isolation from the flock (73%), and 94% later died. Gross pathology exams revealed septicemia characterized by severe hepatitis, pneumonia, tracheitis, enteritis, and encephalitis. Swab and necropsy samples tested positive for Influenza A by PCR and were later identified as H9N2 through whole genome sequencing. We generated complete H9N2 genomes for two individuals. No additional pathogens were found. Phylogenetic analysis across all eight segments revealed that the viruses were low pathogenicity H9N2 AIV strains of North American origin, which indicated this outbreak was a new introduction of the virus into South America. We also performed a comparative mutational analysis and identified multiple mutations previously associated with mammalian host adaptation, increased virulence, increased pathogenicity, and increased virus binding to α2-6 receptors, which may explain the high mortality rates observed despite the supposedly low pathogenicity of the strain. We also identified novel mutations specific to rhea viruses that will need to be experimentally validated. This is the first report of a natural H9N2 systemic infection in an avian host, highlighting a need for increased surveillance efforts for zoonotic influenza viruses with pandemic potential.

Competing Interest Statement

The authors have declared no competing interest.

Source: 

Link: https://www.biorxiv.org/content/10.64898/2026.05.08.723762v1

____

#Peru - #Influenza A #H5 viruses of high pathogenicity (Inf. with) (non-poultry including wild birds) (2017-) - Immediate notification

 

In the framework of passive surveillance activities, a report was received regarding backyard poultry (not considered as poultry) with clinical symptoms consistent with avian influenza. An outbreak of high pathogenicity avian influenza has been confirmed in the Cajabamba district of the Cajamarca department. The birds showed clinical signs such as weakening, hoarseness, eye discharge, and diarrhoea. The Official Authority activated quarantine, control, and surveillance measures in the outbreak and around the outbreak with the aim of identifying possible cases and preventing the spread of the outbreak.

A notification was received regarding sick birds in a backyard (turkeys, ducks, roosters, hens, geese, and chickens) showing signs of depression, diarrhoea, and hoarseness.

Source: WOAH, https://wahis.woah.org/#/home

Link: https://wahis.woah.org/#/in-review/7358

____

#Spillover of #H5 #influenza viruses to vampire #bats at the marine-terrestrial interface

 

Abstract

The highly pathogenic H5N1 avian influenza A virus (IAV) clade 2.3.4.4b has spread globally and spilled over into multiple mammalian species, raising concerns about its pandemic potential. In late 2022, clade 2.3.4.4b viruses devastated seabird and marine mammal populations along the Pacific coast of South America. Here, we report the first evidence of H5 IAV infections in wild bats globally, focusing on common vampire bats (Desmodus rotundus) in coastal areas of Peru. Longitudinal serological screening, stable isotope analysis and metabarcoding revealed repeated exposures to H5 IAVs in vampire bats which feed on coastal wildlife species heavily impacted by the 2.3.4.4b epizootic, but no evidence of infection in populations without access to marine prey. We further report bat gene flow between IAV-exposed and IAV-naive populations, and IAV infections in a vampire bat colony that fed on both marine and terrestrial livestock prey, providing insights into how future IAV epizootics might spread spatially within bats and between marine and terrestrial ecosystems if a bat reservoir were established. Immunohistochemistry demonstrated that the H5 haemagglutinin protein binds to the upper respiratory tract of vampire bats, suggesting bat tissue susceptibility to H5 IAVs. Finally, vampire bat-derived kidney, liver, and lung cells supported entry, replication, and egress of avian and mammalian 2.3.4.4b viruses, confirming cellular infectivity. These results illustrate how combining ecological inference and experimental virology can pinpoint the species origins and biological significance of viral spillover at species interfaces. Recurrent exposures from marine wildlife, tissue and cellular susceptibility to H5N1 IAVs, and connections to other IAV-susceptible terrestrial mammals establish the prerequisite conditions for vampire bats to spread IAVs between marine and terrestrial environments or to form a novel reservoir of highly pathogenic IAVs.

Competing Interest Statement

The authors have declared no competing interest.

Funder Information Declared

Wellcome Trust, https://ror.org/029chgv08, 218518/Z/19/Z, 217221/Z/19/Z, CC1114

Medical Research Council, MC_UU_00034/3, CC1114

NSF/Biotechnology and Biological Sciences Research Council, DEB 2011069, BB/V003798/1, BB/V004697/1

Medical Research Council and Department for Environment Food and Rural Affairs (FluTrailMap-One Health), MR/Y03368X/1, BB/Y007298/1

NERC, NE/V014730/1

Biotechnology and Biological Sciences Research Council/Medical Research Council, BB/Y006879/1

Carlsberg Foundation, https://ror.org/01kpjmx04, CF21-0411

Villum Fonden, VIL41390

Francis Crick Institute, Cancer Research UK, CC1114

National Institute of Allergy and Infectious Diseases, https://ror.org/043z4tv69, 75N93021C00015

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.11.09.686930v1

____

Yellow fever - Region of the #Americas (#WHO D.O.N., May 16 '25)

{Summary}

Situation at a glance

From 29 December 2024 and as of 26 April 2025 (with data for Ecuador updated as of 2 May 2025), a total of 212 confirmed human cases of yellow fever, including 85 deaths, have been reported to WHO by five countries in the Region of the Americas (case fatality rate (CFR) 40%). 

The cases have been reported in the Plurinational State of Bolivia, Brazil, Colombia, Ecuador and Peru. 

The 212 confirmed yellow fever cases reported so far in 2025 represent a threefold increase compared to the 61 confirmed cases reported in 2024. 

WHO is supporting affected countries in implementing coordinated actions to respond to the yellow fever cases and outbreaks. 

This includes: 

- enhancing preventive measures, 

- strengthening surveillance and case management, 

- improving risk communication and community engagement, and 

- implementing immunization activities. 

The current yellow fever situation in the Americas is driven by increased sylvatic transmission cycles. 

The occurrence of yellow fever cases outside of the Amazon basin, combined with high fatality, varying vaccination coverage across affected countries, and limited vaccine supply, contributes to the overall classification of yellow fever risk in the Region of the Americas, especially in endemic countries, as high. 

WHO emphasizes the importance of active surveillance, timely laboratory testing, cross-border coordination, and information sharing. 

Vaccination remains the primary means for the prevention and control of yellow fever. 

WHO continues to support countries in expanding vaccination coverage through routine immunization programs and mass vaccination campaigns to enhance population immunity and reduce the risk of outbreaks.

(...)

Source: World Health Organization, https://www.who.int/emergencies/disease-outbreak-news/item/2025-DON570

____

Co-Circulation of 2 #Oropouche Virus #Lineages during #Outbreak, #Amazon Region of #Peru, 2023–2024

Abstract

We describe introduction of the 2022–2023 Oropouche virus lineage from Brazil, which has caused large-scale outbreaks throughout Brazil, into the Amazon Region of Peru. This lineage is co-circulating with another lineage that was circulating previously. Our findings highlight the need for continued surveillance to monitor Oropouche virus in Peru.

Source: US Centers for Disease Control and Prevention, https://wwwnc.cdc.gov/eid/article/31/4/24-1748_article

____