Biological markers of infection may assist in the identification of early stage viral infection and serve as a surrogate biomarker to identify asymptomatic Ross River or Barmah Forest virus infection

Abstract

Abstract Background and Aims Although Ross River virus (RRV) and Barmah Forest virus (BFV) pose a risk to transfusion safety, in Australia, blood donations are not screened for either. RRV and BFV pathogenesis is poorly understood; however, mannose binding lectin (MBL) levels have been associated with RRV disease severity. We investigated biological markers to identify early stages of infection in asymptomatic RRV or BFV infection. Methods Samples from 7001 blood donations from donors at risk for RRV and/or BFV were tested for anti-RRV (IgM) and/or anti-BFV (IgM). MBL level was assessed in 139 anti-RRV (IgM) positive samples, 143 anti-BFV (IgM) positive samples and clinical samples (10 RRV, 10 BFV). MCP-1, MIG, TNF-α, IFN-α, IFN-γ, IL-8, IL-10 and IP-10 were quantified in these samples and 50 seronegative samples. Results Anti-RRV (IgM) was detected in 2.3%, and anti-BFV (IgM) in 2.4%, of donations, consistent with asymptomatic infection. MBL deficiency was not associated with seropositivity, but higher MBL levels were evident in RRV patients. IP-10, MIG, MCP-1 and IL-8 were elevated in RRV patients and IFN-γ, MCP-1 and IL-8 higher in BFV patients. For both anti-RRV (IgM) and anti-BFV (IgM) positive donations, IL-8 was elevated compared to IgM negative donors. All statistical analysis unpaired T-test, 95% CI. Conclusions Asymptomatic RRV or BFV infection occurs in blood donors. The frequency of MBL deficiency was similar between samples from clinical and presumed asymptomatic RRV or BFV infection. Measurement of IL-8 may assist in the identification of early stage viral infection and function as a surrogate biomarker for early stage RRV or BFV infection.