Location: Zoonotic and Emerging Disease Research
Project Number: 3022-32000-021-029-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jul 21, 2026
End Date: Jul 20, 2029
Objective:
The overall objective of this collaborative project is to define ecological, geographic, and host-associated factors that influence the movement and spillover of Crimean-Congo hemorrhagic fever virus (CCHFV) and CCHFV-associated ticks, and to use those data to estimate potential risk to the United States. CCHFV has one of the widest known geographic ranges of any tick-borne viral hemorrhagic fever, yet major gaps remain in understanding where virus activity occurs, how genetically diverse circulating strains are, what animal and tick communities support local maintenance, and how infected ticks or exposed hosts could move into new regions. This work will build on established international partnerships and ongoing field-based studies in the Democratic Republic of Congo, the Czech Republic and neighboring Eastern European countries, and Turkey, a recognized region of intense CCHFV activity. Specific objectives are to:
Define ecological and husbandry factors associated with CCHFV activity at livestock and wildlife interfaces. Existing and newly generated serologic, tick, animal, farm-management, and site-level data from DRC farms and partner sites in Eastern Europe and Turkey will be harmonized to identify factors associated with animal exposure and tick presence.
Characterize tick species composition, host associations, and viral genetic diversity across linked international study sites. Tick collections from livestock, wildlife, companion animals, and the environment will be identified morphologically and molecularly, tested for CCHFV and related nairoviruses, and, when feasible, sequenced to evaluate viral diversity and relationships among regions.
Evaluate the role of migratory birds in the long-distance movement of ticks relevant to CCHFV ecology. Bird-associated ticks will be collected through partner networks and analyzed to determine species identity, life stage, geographic origin when possible, and pathogen status, with emphasis on routes that could connect CCHFV-endemic regions with areas where competent tick species or suitable hosts occur.
Integrate field, laboratory, geospatial, host, and movement data into predictive models of CCHFV spread and potential U.S. introduction risk. Models will assess ecological suitability, tick-host connectivity, livestock and wildlife interface factors, migratory bird pathways, and plausible entry points relevant to U.S. agriculture and public health preparedness.
Approach:
This project will use a comparative, multi-region framework that links field ecology, laboratory testing, data harmonization, and predictive modeling. UCLA and USDA-ARS will combine complementary expertise in tick ecology, host-pathogen systems, geospatial analysis, and high-consequence zoonotic viruses to develop an integrated assessment of CCHFV risk and potential pathways relevant to the United States.
First, the project will consolidate data and samples from existing CCHFV-focused partnerships. In DRC, prior work has mapped CCHFV activity around farms using serology while collecting detailed metadata on animal species present, herd structure, animal movement, husbandry practices, tick burden, farm environment, and human-animal contact patterns. Comparable datasets and tick collections from the Czech Republic, surrounding Eastern European countries, and Turkey will be incorporated to support cross-site comparisons. Data elements will be standardized across projects, including host species, tick species, collection method, site characteristics, animal management, serologic results, molecular test results, and geospatial coordinates.
Second, tick and animal samples will be analyzed using a tiered laboratory strategy. Ticks will be identified by morphology and confirmatory molecular barcoding as needed. Tick pools and available animal specimens will be tested for CCHFV and related nairoviruses using molecular assays, and positive or high-priority specimens will be advanced for sequencing to define viral diversity and phylogeographic relationships. Animal sera will be analyzed using available serologic platforms to identify evidence of prior exposure, with attention to livestock species that may amplify risk at the farm level and wildlife or companion animal interfaces that may indicate broader local circulation.
Third, the project will add a focused migratory bird component to address long-distance tick movement. Partner networks will collect ticks from migratory birds or bird stopover sites in regions linked to CCHFV activity. These collections will be used to determine whether bird-associated ticks include species capable of maintaining or transmitting CCHFV, whether transported ticks overlap with livestock or wildlife habitats, and whether migration pathways could contribute to movement of infected ticks or expansion of ecologically suitable tick populations.
Finally, all field and laboratory data will be integrated into spatial and statistical models to estimate risk. Models will incorporate tick distribution, host community structure, animal management practices, viral genetic relationships, bird movement pathways, land use, and environmental suitability. Outputs will identify ecological features associated with CCHFV activity abroad, rank potential pathways for movement toward new regions, and evaluate where U.S. livestock systems, wildlife interfaces, and tick habitats could be vulnerable if CCHFV or infected ticks were introduced. The resulting framework could support risk-based planning, targeted field sampling, and prioritization of diagnostic, tick-control, and response capabilities for U.S. agriculture.