Poster Presentation 14th Lorne Infection and Immunity 2024

An insect-specific chimeric vaccine protects saltwater crocodiles (Crocodylus porosus) against West Nile virus-induced skin lesions and viremia (#143)

Gervais Habarugira 1 2 , Jessica J Harrison 2 , Jasmin Moran 3 , Willy W Suen 2 4 , Agathe MG Colmant 2 5 6 , Jody Hobson-Peters 2 5 , Sally R Isberg 3 , Helle Bielefeldt-Ohmann 2 5 , Roy A Hall 2 5
  1. School of Veterinary Science, The University of Queensland, Gatton, Quensland, Australia
  2. School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Quensland, Australia
  3. Centre for Crocodile Research, Noonamah, The Northern Territory, Australia
  4. Australian Centre for Disease Preparedness, The Commonwealth Scientific and Industrial Research Organisation, Geelong, Victoria, Australia
  5. Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Quensland, Australia
  6. Unité des Virus Émergents (UVE) Aix-Marseille Univ-IRD 190-Inserm 1207, Marseille, France


West Nile virus (WNV) is a mosquito-borne zoonotic flavivirus causing mild to severe disease in humans, domestic and wildlife animals species. In saltwater crocodiles, WNV causes skin lesions, known as "pix", leading to economic losses of AUD20 million annually due to hide rejection. Currently, no vaccine for WNV is commercially available in Australia. This study aimed to develop a vaccine preventing WNV-induced skin lesions in farmed saltwater crocodiles.

Material and methods

We assessed the efficacy and safety of a flavivirus chimeric vaccine comprising the genome backbone of the insect-specific Binjari virus (BinJV) and genes for the structural prM and envelope (prME) proteins of WNV. The BinJV/WNV-prME chimeric virus vaccine is antigenically similar to wild-type WNV but replication-defective in vertebrates. Crocodiles were vaccinated with two doses of BinJV/WNV-prME administered at a four-week interval and WNV-challenged four weeks after booster vaccination. Serum samples collected at different time points were tested in a pan-flavivirus blocking ELISA and virus neutralisation test (VNT).


Vaccinated crocodiles developed a robust neutralising antibody response, regardless of whether the vaccine was adjuvanted or not. Vaccinated crocodiles showed no adverse effects and were fully protected from viremia and skin lesions when challenged with a Kunjin strain of WNV. Mock-vaccinated crocodiles became viraemic, and 22.2% exhibited WNV-induced skin lesions.


Our findings suggest that the BinJV/WNV-prME chimera is a safe and efficacious vaccine that prevents WNV-induced skin lesions in farmed crocodiles. This is the first vaccine that protects against a viral disease in a reptile.

  1. Habarugira, G., Suen, W. W., Hobson-Peters, J., Hall, R. A. & Bielefeldt-Ohmann, H. West Nile Virus: An Update on Pathobiology, Epidemiology, Diagnostics, Control and "One Health" Implications. Pathogens 9 (2020).
  2. Hobson-Peters, J. et al. A recombinant platform for flavivirus vaccines and diagnostics using chimeras of a new insect-specific virus. Sci. Transl. Med. 11, eaax7888 (2019).
  3. Habarugira, G. et al. A chimeric vaccine protects farmed saltwater crocodiles from West Nile virus-induced skin lesions. NPJ Vaccines 8, 93 (2023).