Scientists from Germany have developed a new molecular technique for detecting the deadly KHV virus.
The technique uses the Polymerase Chain Reaction (PCR) to amplify tiny quantities of genetic material to detect the presence of the viral DNA, and is believed to be capable of detecting the presence of the disease at levels 10 times lower than those currently used.
El-Matbouli, Rucker and Soliman of the University of Munich's Faculty of Veterinary Medicine announced the details of the new protocol in a recent issue of the journal Diseases of Aquatic Organisms.
Koi Herpes Virus, which is now formally known as Cyprinid Herpes Virus-1 (CyHV-1) among scientists, became a notifiable disease in 2007 and the public now have a legal obligation to report suspected cases to the authorities; however, the disease remains difficult to detect accurately.
Based on an experimental modification called "nested PCR", the new technique is designed to reduce the likelihood of contamination in products due to the amplification of unexpected primer binding sites.
The authors said: "The 2-round PCR amplified 529 and 379 bp segments of the CyHV-3 gene coding for the major capsid protein using specific external and internal primers, respectively.
"The PCR test did not amplify genomic DNA from either Cyprinid herpesvirus-1 (CyHV-1) or Cyprinid herpesvirus-2 (CyHV-2).
"The nested PCR test detected CyHV-3 DNA at a 10-fold lower concentration than a routinely used, 1-round test."
The scientists believe the new 2-round nested PCR method will provide a more sensitive diagnosis for detecting the virus in carp populations.
For more information see: El-Matbouli M, Rucker U, Soliman H (2007) - Detection of Cyprinid herpesvirus-3 (CyHV-3) DNA in infected fish tissues by nested polymerase chain reaction. Dis Aquat Organ. 2007 Oct 31;78(1):23-8.