Transmission of the virus has been demonstrated to occur by contact with infected fish or their secretions.

Contact with equipment or people who have handled infected fish also transmits the virus.

During this time it was reported that up to 60% of infected fish died before they could successfully spawn.

The definitive host is known to get infected by consuming infected fish.

In heavily infected fish it can cause a rapid loss of condition, considerable distress and death.

Damage caused to the gill tissue of an infected fish can also reduce respiratory efficiency.

Upside-down swimming near the surface A subclinically infected fish will not show any of these signs.

A subclinically infected fish may initially only have a single trophozoite.

This behavior makes the infected fish 30 times more likely to be caught and consumed by a bird.

As the name implies, it causes severe anemia of infected fish.