Large-scale international validation of an indirect ELISA based on recombinant nucleocapsid protein of Rift Valley Fever virus for the detection of IgG antibody in domestic ruminants

Authors: PAWESKA, JANUSZ - National Institute For Communicable Diseases (NICD); JANSEN VAN VUREN, PETRUS - Commonwealth Scientific And Industrial Research Organisation (CSIRO); MSIMANG, VEERLE - National Institute For Communicable Diseases (NICD); MOUSTAPHA LO, MODU - National Laboratory For Animal Husbandry And Veterinary Research (LNERV); THIONGANE, YAYA - National Laboratory For Animal Husbandry And Veterinary Research (LNERV); MULUMBA-MFUMU, LEOPOLD - Ministry Of Agriculture, Democratic Republic Of Congo; MANSOOR, LAQADASI - Food And Agriculture Organization Of The United Nations (FAO); FAFETINE, JOASE - Eduardo Mondlane University; MAGONA, JOSEPH - National Livestock Research Institute; BAZANOW, BARBARA - Wroclaw University Of Environmental And Life Sciences; Wilson, William - Bill; PEPIN, MICHEL - French Agency For Food, Environmental And Occupational Health & Safety (ANSES); UNGER, HERMANN - International Atomic Energy Agency (IAEA); VILJOEN, GERRIT - International Atomic Energy Agency (IAEA)

Submitted to: Viruses
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/13/2021
Publication Date: 8/19/2021
Citation: Paweska, J.T., Jansen Van Vuren, P., Msimang, V., Moustapha Lo, M., Thiongane, Y., Mulumba-Mfumu, L.K., Mansoor, L., Fafetine, J.M., Magona, J., Bazanow, B., Wilson, W.C., Pepin, M., Unger, H., Viljoen, G. 2021. Large-scale international validation of an indirect ELISA based on recombinant nucleocapsid protein of Rift Valley Fever virus for the detection of IgG antibody in domestic ruminants. Viruses. 13(8). Article e1651. https://doi.org/10.3390/v13081651.
DOI: https://doi.org/10.3390/v13081651

Interpretive Summary: Rift Valley fever virus (RVFV) is and mosquito-borne pathogen of ruminants, camels and humans endemic in Sub-Saharan Africa. The presence of the disease is associated with socio-economic losses and outbreaks result in hemorrhagic fever in animals and humans. It is of animal and public health concern especially with climate change that could affect the epidemiology of this vector-borne virus. Since the disease can be fatal and no human vaccine or treatment is available diagnosis requires high biosafety facilities. Even production of the reagents for this test can require high biosafety; however, a serological assay was previous developed base on recombinant technology that can be produced at lower biosafety. In this study, a large validation of this assay was performed using samples from six endemic and three non-endemic countries. The test was found to be highly accurate, easy to perform and safe assay, it can be used outside expensive biocontainment facilities (with virus heat-inactivation of serum) and be automatized. This large international validation study provides a valuable RVFV surveillance tool particularly important for less-resourced countries.

Technical Abstract: Diagnostic performance of an indirect enzyme-linked immunosorbent assays (I-ELISA) based on recombinant nucleocapsid protein (rNP) of Rift Valley fever virus (RVFV) was validated for the detection of IgG antibody in sheep (n = 3367), goat (n = 2632) and cattle (n = 3819) sera. Validation data sets were dichotomized according to the results of a virus neutralization test in sera obtained from RVFV-endemic (Burkina Faso, Democratic Republic of Congo, Mozambique, Senegal, Uganda, Yemen) and RVFV-free countries (France, Poland, USA). Cut-off values were defined using the two-graph receiver operating characteristic analysis at 95% accuracy level. Estimates of the diagnostic specificity of the RVFV rNP I-ELISA in animals from RVF-endemic countries ranged from 98.6 % (cattle) to 99.5 % (sheep) while in those originating from RVFV-free countries, they ranged from 97.7% (sheep) to 98.1% (goats). Estimates of the diagnostic sensitivity in ruminants from RVF-endemic countries ranged from 90.7% (cattle) to 100% (goats). The results of this large-scale international validation study demonstrate the potential use of the RVFV rNP I-ELISA for disease-surveillance investigations. As highly accurate, easy to perform and safe assay, it can be used outside expensive biocontainment facilities and be automatized. These advantages are particularly important for less-resourced countries where there is a need to accelerate and improve RVF surveillance, research on epidemiology, as well as to advance diseases control measures.