Fig. 1

Zebrafish embryos are susceptible to IAV infection, and IAV replicates in zebrafish hosts. PBS- or IAV-injected zebrafish embryos were monitored for 5 days post infection for quantification of cumulative percent survival (A) and viral burden (B). The results represent three separate experiments. (A) Cumulative percentage survival of zebrafish infected at 48 hpf with IAV APR8 or X-31 (n=50 fish per treatment). Significantly fewer zebrafish survived in either IAV-infected group compared with controls (***P<0.001). (B) Quantification of viral burden in zebrafish infected with APR8 or X-31 (n=20 fish per treatment). Viral burden increases 10- to 20-fold in APR8- or X-31-infected zebrafish. In APR8-infected embryos, viral burden increased steadily over time through to 96 hpi. In X-31-infected zebrafish, viral burden peaked around 48 hpi. These data demonstrate IAV replicates within zebrafish and suggest that death in IAV-infected zebrafish is likely to be caused by infection with the virus.