Community-Based Surveillance for Highly Pathogenic Avian Influenza Viruses among Deceased Birds

A 2025 community-based surveillance initiative in Galveston County, Texas, successfully detected and characterized highly pathogenic avian influenza H5N1 (clade 2.3.4.4b, genotype D1.1) in 70% of reported deceased birds through cross-sectoral collaboration, enabling rapid response and preventing human infections.

The Gist

Imagine a neighborhood watch program, but instead of looking out for burglars, the neighbors are on the lookout for sick birds. That is essentially what this paper describes: a community-driven mission in Galveston County, Texas, to catch a dangerous flu virus before it spreads to people or livestock.

Here is the story of how they did it, broken down into simple terms.

The Setup: A Neighborhood Watch for Birds

Think of the H5N1 bird flu (Highly Pathogenic Avian Influenza) as a "wolf in sheep's clothing." It's a virus that usually lives in wild birds but can be deadly to them, and it has the potential to jump to chickens, cows, and even humans.

In 2025, a team of experts decided to set up a "tripwire" in Galveston County. This area is like a major rest stop for migratory birds flying between North America and South America. Because so many birds stop there, it's a perfect place for the virus to hitch a ride.

The team was a "One Health" alliance, meaning they brought together:

• The Police: The local Health District and Animal Services (who handle the dead birds).
• The Detectives: University scientists (who test the samples).
• The Neighbors: The general public (who call if they find a dead bird).

The Mission: Catching the "Wolf"

The process worked like a relay race:

1. The Sighting: A resident sees a dead bird or a bird acting strangely (like stumbling or having seizures) and calls the local health district.
2. The Pickup: The Animal Services team, wearing protective gear (like hazmat suits), picks up the bird. They take two "swabs" (like giant Q-tips) from the bird's throat and rear end.
3. The Lab Test: The samples are rushed to a university lab. The scientists run a series of tests:
   • The Metal Detector: First, they check if the bird has any flu virus.
   • The ID Check: If it's flu, they check if it's the dangerous "H5" or "H7" type.
   • The Deep Dive: If it's the bad kind, they grow the virus in a petri dish (like growing a mold culture) and then use a high-tech scanner (Next-Generation Sequencing) to read the virus's entire genetic code.

The Findings: The Virus Was There

Between November and December 2025, the team collected 10 dead birds.

• The Hit Rate: 7 out of 10 birds (70%) tested positive for the deadly H5N1 virus.
• The Identity: The virus wasn't just any flu; it was a specific "hybrid" version known as Genotype D1.1.
  • Analogy: Imagine a car built with an engine from a European sports car and a chassis from an American truck. This virus is a genetic mix: half its genes came from Eurasian birds, and half came from North American birds. This mix makes it a very efficient traveler.
• The Danger Signs: The scientists found specific "typos" in the virus's genetic code. These typos are like warning lights on a dashboard. They suggest the virus is getting better at infecting mammals (like cats or humans) and might be harder to stop with current medicines.

The Human Element: No One Got Sick

Ten people in the community had touched these infected birds. The team acted fast:

• They gave 8 of them a preventative pill (Tamiflu) just in case.
• They monitored everyone for symptoms.
• The Result: Zero human infections. The "tripwire" worked perfectly; it caught the virus in the birds before it could jump to people.

Why This Matters

This paper isn't just about dead birds; it's about early warning systems.

• The Canary in the Coal Mine: Wild birds are the canaries. If they are dying, it means the virus is active in the area.
• The Domino Effect: If the virus stays in wild birds, it might jump to a chicken farm, then to a cow, and eventually to a human. By catching it in the birds, they stop the dominoes from falling.
• Community Power: This proves that regular people don't need to be scientists to help fight pandemics. If you see a dead bird and call the right number, you are part of the global defense team.

The Bottom Line

The virus is out there, evolving and mixing its genes like a deck of cards. But thanks to a collaboration between neighbors, animal control, and scientists, Galveston County proved that we can spot the danger early, understand what the virus is doing, and keep our communities safe. It's a reminder that in the fight against invisible enemies, the best weapon is often a sharp eye and a quick phone call.

Technical Summary

1. Problem Statement

Highly Pathogenic Avian Influenza (HPAI) viruses, specifically the H5N1 clade 2.3.4.4b, have escalated into a global panzootic since 2020. These viruses pose significant threats to:

• Wildlife: Causing mass die-offs and threatening biodiversity.
• Livestock: Spreading to poultry and, increasingly, mammals (e.g., dairy cows, cats).
• Humans: Presenting zoonotic risks, with sporadic infections documented in workers.

Traditional public surveillance systems often lack the capacity for rapid, localized detection in wildlife. Galveston County, Texas, a critical stopover on the Central Migratory Flyway with over 300 bird species, is a high-risk zone for virus introduction and spread. There is an urgent need for a "One Health" approach that integrates community reporting with rapid genomic characterization to detect viral adaptations and prevent spillover.

2. Methodology

The study employed a multidisciplinary, community-based surveillance model initiated in February 2025, involving the Galveston County Health District (GCHD), the University of Texas Medical Branch (UTMB), and local animal services.

• Surveillance Strategy:

  • Citizen Science: The public was educated to report dead wild/domestic birds or birds with neurological symptoms to GCHD.
  • Sample Collection: GCHD Animal Services collected oropharyngeal and cloacal swabs from deceased birds reported between November and December 2025. Samples were transported in viral transport medium (VTM) under a cold chain (2–8°C) to UTMB within 24 hours.
  • Ethical Oversight: The protocol was reviewed by UTMB's IACUC; formal review was waived as no live animals were handled, only deceased carcasses.

• Laboratory Workflow:

  • Inactivation & Extraction: Samples were inactivated in a BSL-3 Enhanced (BSL3E) lab using TRIzol™ LS. RNA extraction was performed in a BSL-2 lab.
  • Molecular Detection:
    • RT-qPCR: Screening for Influenza A (Matrix gene), followed by subtyping for H5 and H7.
    • Pathogenicity Confirmation: RT-PCR targeting the Hemagglutinin (HA0) cleavage site to distinguish HPAI from Low Pathogenic Avian Influenza (LPAI).
    • Sanger Sequencing: Used to confirm the HA0 cleavage site and Neuraminidase (NA) gene identity.
  • Virus Isolation: Positive samples were cultured in Madin-Darby Canine Kidney (MDCK) cells in BSL3E.
  • Genomic Characterization:
    • Next-Generation Sequencing (NGS): Whole-genome sequencing using the Oxford Nanopore MinION platform.
    • Bioinformatics: Data analysis included consensus genome generation, mutation analysis (FluSurver), phylogenetic tree construction (IQ-TREE), and genotyping (GenoFLU) to identify reassortment patterns.

3. Key Contributions

• Operational Model: Demonstrated the feasibility of a rapid-response, cross-sectoral surveillance system linking public reporting, local health departments, and academic research labs.
• Rapid Genomic Surveillance: Successfully integrated field sampling with high-throughput sequencing (Nanopore) and Sanger sequencing to characterize circulating strains within weeks of collection.
• Public Health Intervention: Established a protocol for immediate risk assessment, offering antiviral prophylaxis (oseltamivir) to exposed community members and monitoring household animals.

4. Results

• Sample Demographics: 10 dead birds were sampled (4 Muscovy ducks, 1 chicken, 1 duck hybrid, 1 Woodcock-like bird, 1 Cattle Egret, and 1 unidentified wild bird) from various locations in Galveston County.
• Detection Rates:
  • 7 out of 10 (70%) birds tested positive for Influenza A virus.
  • All positive samples were confirmed as H5N1.
  • Sanger sequencing confirmed the presence of the multibasic HA cleavage site, verifying them as HPAI.
  • All H5N1 strains possessed the N1 neuraminidase gene.
  • Virus was successfully isolated in MDCK cells from all 7 positive samples.
• Genomic Analysis:
  • Genotype: The viruses exhibited a 4:4 reassortant constellation consistent with Genotype D1.1 within clade 2.3.4.4b.
    • Eurasian Avian Lineage: PB1, HA, MP, NS.
    • North American LPAI Lineage: PB2, PA, NP, NA.
  • Mutations: Notable amino acid substitutions were identified in segments PB2 (I495V, A676T), PB1 (S375N), NA (P272S, N329S), and NS1 (D171N, P87S). These mutations are associated with enhanced polymerase activity, mammalian adaptation, and potential immune evasion.
• Human Exposure:
  • 10 community members reported direct contact with infected birds.
  • 8 received post-exposure prophylaxis (oseltamivir).
  • Zero human infections were detected; all symptomatic exposed individuals tested negative for influenza.

5. Significance

• Early Warning System: The detection of Genotype D1.1 in wild birds serves as a critical early warning for poultry operations and the potential for mammalian spillover.
• Evolutionary Monitoring: The identification of specific mutations (e.g., in PB2 and NS1) linked to mammalian adaptation and virulence highlights the dynamic nature of the virus. Continuous genomic monitoring is essential to track the accumulation of mutations that could increase zoonotic risk.
• One Health Implementation: The study validates that community involvement combined with cross-sectoral collaboration (public health, veterinary services, and research institutions) is an effective strategy for rapid detection and characterization of emerging avian influenza threats.
• Policy Implication: Sustained local surveillance is deemed essential for risk assessment and preventing the spread of HPAI to domestic livestock and humans.

Data Availability: All genome sequences have been deposited in GenBank (Accession: PX995912–PX996007) and GISAID (Accession: EPI_ISL_5152143–EPI_ISL_5152238).