A new study has shown that carp faeces can be analysed to determine whether the fish are carriers of the deadly Koi Herpes Virus.
Scientists from the Department of Pathology at the Hebrew University-Hadassah Medical School in Jerusalem, Israel, used the Polymerase Chain Reaction (PCR) molecular technique to analyse droppings and found that they contained viral DNA that could be used in diagnoses.
Not only did the faeces contain viral antigens, which can be used to show that the fish has previously been exposed to the virus, they also carried active virus particles.
The faeces of infected carp were shown in the laboratory to be capable of infecting common carp brain cells, and also of triggering the disease in so-called naiive fish that had not previously encountered KHV before.
The findings, which have just been reported in the journal Applied Environmental Microbiology, may lead to non-invasive tests for KHV in fish so that invasive tissue samples don't need to be taken from the fish.
It is also possible that the virus may remain active in fish droppings during the non permissive seasons, the team said.
The team had previously demonstrated that virus is present mainly in the kidneys and liver of infected fish.
Koi Herpes Virus, or KHV, is a major disease affecting carp and is also known as Cyprinid Herpes Virus 3 (Cy-HV3) and Carp Interstitial Nephritis and gill necrosis Virus (CNGV).
For more details see the paper: Dishon A, Perelberg A, Bishara-Shieban j, Ilouze M, Davidovich M, Werker S and M Kotler (2005) - Detection of carp interstitial nephritis and gill necrosis virus in fish droppings. Applied Environmental Microbiology, 2005, No; 71 (11): 7285-91.