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 |  Subject: New Vaccine - August 2009 Thu Sep 10, 2009 4:24 pm | |
| Sourced from http://www.henderson-morley.com/news.php
Result of KHV Study - August 2009
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The Board of Henderson Morley, the AIM quoted biotechnology company, is pleased to announce the results of the Koi Herpes Virus (KHV) Vaccine field studies that have now been completed in a sub-contract research facility.
Highlights
- Henderson Morley’s KHV vaccine field study has produced positive results
- In two of the vaccine groups 96% and 93% of the vaccinated fish survived the study and remained healthy
- Two successful vaccine candidates are now being developed further with a view to presenting these candidates to Schering Plough Animal Health
- KHV disease is classed as a ‘Notifiable-Disease’ by the World Organisation of Animal Health. KHV is therefore a pathogen of growing economic and environmental importance
About the Study
In this study, eight different vaccine candidates were studied. These candidates were formulated to examine the effects of different doses of vaccine, addition of purified virus particles, formulation of candidates with different adjuvants (components of the vaccine that boost immune responses), and different combinations of adjuvants. Adjuvants, that the Directors believe, have never been used in fish vaccines before, were also examined.
Ten groups of Koi carp were held in isolated tanks each with individual water supplies, of which eight groups were vaccinated with candidate vaccines. One group received no vaccine (negative control), and another group were survivors of prior KHV infection, (positive controls).
Results
The unvaccinated negative control group died from KHV infection, as did the fish in some of the unsuccessful low dose vaccine groups. The Board is very pleased that in two of the vaccine groups, 96% and 93% of the vaccinated fish survived, and remained healthy following the virus challenge and for the month following the virus challenge. Other vaccine groups had 76% and 79% survival; however these candidates are not being selected for further development.
Vaccine Candidates
The candidates used in this study utilise inactivated virus, so pose no threat of infection either to the vaccinated fish or other fish in the same tank or pond. The candidates comprises proprietary methods and techniques developed in-house at the Birmingham (UK) laboratories and do not have PREPS or L-particles in their manufacture. New patents are in preparation to protect the current lead candidates.
KHV
KHV is a serious viral infection that infects all species of carp, including the high value and in-bred ornamental fish, Koi carp. The virus was first isolated in 1996, and has now been detected in over 20 countries. Consequently, in 2006 the World Organisation of Animal Health (OIE) gave KHV disease ‘Notifiable Disease’ status. As a Notifiable Disease there is a legal obligation to report any suspicion of a clinical outbreak of Koi Herpes Virus disease to the Fish Health Inspectorate (FHI). KHV is therefore a pathogen of growing economic and environmental importance.
A single fish infected by KHV may rapidly spread the disease and this often kills between 90% and 100% of fish in the infected pond or tank, with the potential to devastate entire fish farms. The virus is temperature sensitive and is mainly active in warm weather conditions. There is currently no available anti-viral treatment or vaccine licensed in the EU, US or Japan.
A particular problem with KHV, which is similar to other herpes viruses in humans and animals, is the ability to cause latent infection. Once a fish has been infected, or exposed to the live virus, the infection may recur (usually in response to stressors such as high water temperature), without further exposure to the virus. Once infected, fish may also shed the virus into a pond, even in the absence of symptoms.
Live virus challenge
Approximately two months after receiving the vaccines (to allow the fish to develop immune responses), fish were challenged with live Koi Herpes virus that had been characterised by Polymerase Chain Reaction (PCR), a technique used in molecular biology for creating multiple copies of DNA from a sample which results in a very accurate diagnosis and typing of virus infections.
Further development
The two successful vaccine candidates are now being developed further with a view to presenting these candidates to Schering Plough Animal Health under the terms of the development and option to license agreement as soon as possible.
Chairman Andrew Knight commented “We are extremely pleased with the results of this study which demonstrate a level of efficacy for our vaccine technology and reinforces our decision to transform Henderson Morley into a pure play vaccine company by 2011. We look forward to bringing further news on this exciting development in due course. ” |
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