Location: Zoonotic and Emerging Disease Research
Project Number: 3022-32000-027-045-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Aug 1, 2026
End Date: Jul 31, 2028
Objective:
Background: Hendra virus (HeV) and Nipah virus (NiV) are highly pathogenic ssRNA viruses in the Henipavirus genus, causing encephalitis and respiratory illness with case fatality rates of 40–75%. Pteropus fruit bats are the natural reservoir; spillover to humans and animals occurs through contaminated food or direct contact. PNG studies document high serological evidence of HeV and NiV in wild bat populations (seroprevalence 3–71%), yet no HNV isolates have been sequenced from PNG despite documented exposure. This knowledge gap prevents understanding of regional viral diversity, spillover origins, and evolution—critical for predicting spillover risk and informing surveillance strategies globally.
Primary Objectives: Determine the presence of, and previous exposure to, HeV and NiV in bat populations and species in close contact with bats in PNG using archived and prospectively collected samples. Isolate and obtain full-genome sequences of HeV and NiV from PNG to characterize regional viral diversity, phylogenetic position, and relationship to spillover-associated lineages.
Secondary Objectives: Understand viral and ecological risk factors for spillover by identifying viral genetic features, host population characteristics, and seasonal/geographic patterns associated with transmission. Characterize the PNG bat virome and microbiome to identify co-circulating henipaviruses and other emerging zoonotic pathogens relevant to spillover risk.
Expected Outcomes: Identification of HNV seropositive bat populations and geographic distribution of exposure, enabling targeted surveillance. PNG HNV isolates and full-genome sequences, revealing regional viral diversity, evolutionary origins, and genetic features (mutations in receptor-binding or immune-antagonist genes) relevant to spillover competence. Characterization of bat infectome, deepening understanding of henipavirus ecology and reservoir host biology. PNG-anchored baseline data to inform One Health strategies for spillover prevention and calibrate predictive spillover-risk models including models for the United States.
Approach:
Retrospective Survey: Obtain archived serum, plasma, tissue (spleen, liver, kidney) from Pteropus bats (Madang, Lae; ~n=121). Screen via ELISA for anti-HeV/NiV IgM/IgG. Confirm seropositive results via live virus neutralization test at BSL-4 facility. Conduct PCR on seropositive and select seronegative samples; forward PCR-positive samples to BSL-4 for virus isolation and full-genome sequencing.
Prospective Survey: Collect samples from Pteropus bat colonies in Madang and Lae during high-spillover-risk seasons (bat migration, feeding peaks). Non-lethal sampling: urine beneath roosting sites; capture of bats for blood, serum, urine, oral/rectal swabs. Additionally collect blood, nasal, fecal samples from domestic/production animals (swine, horses) within 5–10 km of bat colonies and where possible other species in close contact or in potential close contact. Document sampling location, date, bat species, environmental conditions. Screen all via ELISA; confirm via neutralization testing. Conduct PCR on seropositive samples; isolate and sequence PCR-positive samples via NGS.
Spillover Risk Factor Analysis: Map serological prevalence data geographically and temporally to identify spillover hotspots, seasonal peaks, and bat species/populations at highest risk. Analyze PNG isolate genomes via phylogenetics (maximum-likelihood) to determine relationship to spillover-prone clades (Bangladesh NiV, Malaysian NiV) vs. endemic lineages. Conduct selection analyses (dN/dS, PAML) to identify viral mutations enriched in spillover-associated lineages. Assess whether PNG viral sequences carry predicted spillover-competence markers. Correlate viral and ecological data (seroprevalence, phylogenetic position, environmental factors) to identify population-level spillover risk determinants.
Virome Characterization: Perform metatranscriptomics on bat tissues to detect novel or co-circulating henipavirus sequences and other zoonotic pathogens. Assess pathogen diversity and co-infection patterns as risk factors for spillover events.
Data Integration and Spillover Risk Assessment: Synthesize serological distribution, phylogenetic placement, spillover-risk mutations, and virome data to characterize PNG henipavirus ecology and identify risk factors (host, viral, ecological, seasonal) driving spillover potential. Provide PNG-grounded evidence to inform spillover prevention strategies and calibrate predictive spillover-risk models.