In case of KHV, some Koi test negative for the PCR examine after applying the natural healing or ”heating-up” method, so there is a possibility that such misunderstanding might occur. However, a seemingly healthy Koi having tested negative for the PCR examine still continues to have KHV. In other words, a Koi treated with the natural healing or “heating-up” method keeps being a virus carrier Koi. For example, series of experiments conducted by the Fisheries Research Agency and other related research agencies have confirmed that a KHV infected Koi can be treated with the heating-up method at 32 deg C (approx. 89.6 deg F), but the existence of KHV has been identified in that Koi fourteen months after such treatment. If and when such Koi becomes ill due to stress or other reasons, the immune system becomes compromised and the virus becomes active. In 2005 there were suspected cases of KHV carrier Koi having become the infectious source and having expanded the transmission in Koi farms through distribution and transfer. A KHV carrier Koi is healthy at a glance and shows no symptoms, so there is a great possibility that it is sold, temporarily kept, and exhibited at Koi shows, which may become the cause of expanding the infection.

I would like to say this once again. It is a total misunderstanding that “KHV infected Koi treated with the natural healing or “heating-up” method will fully recover and that the disease will not be transmitted to other Koi.”
We want all Koi lovers, dealers, and Koi club members administrating Koi shows to fully be aware of this fact. A seemingly healthy KHV carrier Koi may become the cause of the spread of infection, so we want you to pay close attention to avoid such risk.