Figure 4.

ZIKV replicated in zebrafish was able to infect healthy larvae. The supernatants obtained after centrifugation of the lysate from the 72 hpf ZIKV-infected larvae or control larvae were injected in 72 hpf healthy larvae into the yolk (2 nL) or diluted in E2 0.5× medium (0.04%). After 24 h, larvae were distributed in a 96-well plate (1 larvae/well), and the locomotor activity was analyzed in Zebrabox system. The larvae were exposed to an incubation period of 30 min in the light (lux: 12%) followed by the testing phase consisting of a dark stimulus (lux: 0%) for 1s, alternated by 29s in the light (lux: 12%) for 2.5 min to induce visual stimulation and the startle response. The total distance moved (mm) of each group during the testing period and the average velocity (mm/s) of each group are shown in (A,B). Graphical representation of the larvae tracking during the testing phase (C). The lines represent the distance moved by the larvae at each second during the total experiment period with highlights of testing phase (D). * p < 0.05 compared with the negative control group.