Abstracts Page 5

Seroprevalence of Crimean-Congo hemorrhagic fever and flavivirus infections among Ethiopian domestic animals 

Samia Bedjaoui1, Younes Laidoudi1, Hana Tadesse2, Zerihun Asefa2, Adrien Limozin3, Loïc Comtet3, Bernard Davoust1 and Bersissa Kumsa2, Rafael Forero4

1University Hospital Institute Mediterranean Infection, Veterinary Research Center, Marseille, France 

2College of Veterinary Medicine & Agriculture, Addis Ababa University, Bishoftu, Oromia, Ethiopia

3Innovative Diagnostics, Grabels, France

4IDvet INC, Hampton, USA

Background: Crimean-Congo Hemorrhagic Fever (CCHF) and Flavivirus infections are significant viral diseases with public health implications. CCHF is primarily transmitted through ticks and contact with infected animals, while Flavivirus infections, including Zika and West Nile viruses, are mosquito-borne. Both diseases exhibit a range of symptoms from mild fever to severe illness, highlighting the need for vector control and vaccination strategies.

Methods: A serological study was conducted in 2023 on Ethiopian domestic animals to assess the prevalence of CCHF and Flavivirus using ELISA assays (ID Screen® Flavivirus, ID Screen® CCHF Double Antigen Multi-species, Innovative Diagnostics, France). A total of 215 animals, including horses (n=22), bovines (n=47), sheep (n=37), donkeys (n=39), cats (n=64), and goats (n=6), were tested for CCHF. An additional 271 dogs were included for Flavivirus screening. All animals appeared healthy at the time of sampling.

Results and Discussion: Among the 486 animals tested for Flavivirus, 59 tested positive, yielding a seroprevalence of 12.14%. The highest prevalence was observed in horses (18.2%) and dogs (17.3%). For CCHF, 8 out of 215 animals tested positive, indicating a seroprevalence of 3.7%, with the highest rates in horses (9%) and bovines (6.3%). Statistical analysis revealed a significantly higher Flavivirus infection rate (p < 0.002) compared to CCHF (p = 0.06). Factors such as age, ectoparasite infestation, geographical location, and agroecological conditions influenced infection rates. Notably, Ethiopia's CCHF prevalence was significantly lower than in neighboring countries like Senegal (32.5%) and Uganda (up to 94%).

Conclusion: The findings underscore the necessity for continued surveillance and research into CCHF and Flavivirus epidemiology in Ethiopia. Future studies should consider environmental, socio-economic, and biological factors to inform targeted interventions and improve public health preparedness. Regional collaboration is essential to effectively address zoonotic disease threats in East Africa.

Developing and delivering education and outreach to U.S. beef producers, veterinarians, and transporters about the Secure Beef Supply Plan to further industry preparedness for Foot and Mouth Disease

Julia Herman1*, Danelle Bickett-Weddle2, Michaela Clowser1, Kathy Simmons3

National Cattlemen’s Beef Association, 1Centennial, Colorado, USA & 3 Washington D.C., USA

2 Preventalytics, Ames, Iowa, USA 

*Corresponding author – jherman@beef.org 

Background. The Secure Beef Supply (SBS) Plan for Continuity of Business provides opportunities for U.S. cattle industry stakeholders to voluntarily prepare before a foot and mouth disease (FMD) outbreak. Producer education can reach additional cattle producers, veterinarians, and transporters about the components of an SBS plan. New resources will be developed for the SBS plan for business continuity to improve uptake by industry stakeholders.

Methods. This project is funded by the USDA National Animal Disease Preparedness and Response Program to improve educational resources for SBS. An advisory group of cattle producers and influencers from all cattle sectors conducted a gap analysis of current SBS resources. Resources created, such as handouts, videos, social media tools, and presentations, will be distributed through train-the-trainer programs and posted on the SBS website.

Results. Multiple resources were developed and made publicly available to stakeholders within the cattle industry. These include handouts, videos, continuing education modules available online, webinars, and podcasts that cover topics specific to sectors (cow/calf, stocker/backgrounder, feedlot, livestock hauler/transporter). All resources will be posted on the SBS website.

Conclusion. Streamlining educational information on the SBS website with industry education programs provides consistent and up-to-date information for cattle producers and veterinarians. Preventive planning and disease preparedness prior to an FMD outbreak requires collaboration from the producer to private veterinarians to state animal health officials. These resources will help all tiers of cattle caretakers in biosecurity planning and disease preparedness, seeking to mitigate as much business continuity issues during a potential FMD outbreak.

Src and Abl Kinase Phosphorylation at EPIYA-like Motifs of the Tick-Specific Anaplasma phagocytophilumEffector AteA Leads to Binding of the Tick Signaling Proteins RasGAP and Crk

Brittany Genera1, Eliciane Mattos1, Prabhat Talukdar1, Kelly A. Brayton1, Jason M. Park1 

1 Washington State University, Pullman, Washington, USA

brittany.genera@wsu.edu

Background
Anaplasma phagocytophilum is an obligate intracellular Gram-negative bacterium that causes human granulocytic anaplasmosis (HGA) and is transmitted by Ixodes scapularis ticks. The pathogen infects very different cell and tissue types in its mammalian host and tick vector. To establish and maintain infection, A. phagocytophilum uses a Type IV Secretion System (T4SS) to translocate effector proteins that manipulate host cell pathways and immune responses. Our lab recently identified a novel T4SS effector, AteA (Anaplasmatick effector A), which is crucial for bacterial acquisition and survival in tick cells.

Methods
Western blot was used to assess tyrosine phosphorylation of AteA. Site-directed mutagenesis was performed to identify specific tyrosine residues within the EPIYA-like motifs (EPLYA) as sites of phosphorylation. Synthetic peptides containing phosphorylated EPLYA motifs were used in binding assays to detect interactions with SH2-domain-containing tick signaling proteins.

Results
We found that AteA is phosphorylated at tyrosine residues by host Src and Abl kinases. Mutagenesis revealed that phosphorylation occurs specifically at the tyrosine residues within the EPLYA motifs of AteA. Binding assays with phosphorylated synthetic peptides demonstrated that the tick proteins RasGAP and Crk interact specifically with phosphorylated EPLYA motifs.

Conclusion
These findings suggest that phosphorylation of AteA at EPLYA motifs facilitates interactions with tick signaling proteins involved in host-pathogen dynamics. Understanding these interactions provides new insight into how A. phagocytophilum manipulates tick cell pathways and identifies potential molecular targets for interrupting pathogen transmission at the vector level.

GROWTH KINETICS OF RIFT VALLEY FEVER VIRUS MP-12 VACCINE STRAIN IN VERO CELLS

Luija Mudiyanselage1, Alina D. Mota-Peynado2, William C. Wilson2, Dana Mitzel2, and Jayme Souza-Neto1,3*

1 Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan KS 66502

2 Foreign Arthropod-Borne Animal Diseases Research Unit, United States Department of Agriculture, Agricultural Research Service, National Bio and Agro-Defense Facility, Manhattan, KS 66505

3 Kansas State Veterinary Diagnostic Laboratory, Manhattan, KS 66505

*Corresponding author - jsouzaneto@vet.k-state.edu

Background: Rift Valley Fever Virus (RVFV) is an arthropod-borne virus primarily transmitted by Aedes and Culex mosquitoes. RVFV mainly affects livestock, causing high mortality in young animals. The infection is often mild in humans but can lead to severe complications. RVFV MP-12 is a live attenuated vaccine that can be handled at biosafety level 2 (BSL-2), bringing value as a prototype for RVFV-mosquito studies at lower biocontainment levels, compared to RVFV which is categorized as a select agent and requires handling under a BSL-3. This study characterizes the growth kinetics of MP-12 in Vero cells to determine the optimal time for harvesting high-titer virus for mosquito infection experiments. 

Methods: Vero cells were infected with RVFV MP-12 at MOIs of 0.1 and 0.01, and samples were collected at several time points post-infection (0–96 hours). Viral titers were quantified using plaque assay and qRT-PCR. Growth curves were generated to identify the peak titer window. 

Results: Both plaque assay and qRT-PCR showed that the RVFV MP-12 reached its peak viral titer at 24 hours post-infection in Vero cells under both MOIs tested. A higher viral load was observed at MOI of 0.1 compared to an MOI of 0.01 at the same time point, suggesting that the RVFV MP-12 exhibits optimal titer at 24 hours post-infection with an MOI of 0.1 in Vero cells. 

Conclusion: Understanding the growth kinetics of RVFV MP-12 is crucial for optimizing mosquito infection studies that serve as a safe model for studying RVFV transmission dynamics in mosquitoes compared to wild-type virus.