Thermo-tolerant Launch
• Launch of the thermo-tolerant new castle disease vaccine PDF Print E-mail
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Wednesday, 03 August 2011 09:52

NCD thermostable vaccine

Thermo tolerant I-2 Newcastle Disease Vaccine

Justification

Newcastle disease is a major constraint to indigenous chicken productivity in Kenya and often causes  80-100% mortality in unvaccinated flocks. Outbreaks of Newcastle disease (ND) are unpredictable in many parts of the country and often discourage farmers from investing in the management and welfare of rural chicken.  In many cases, vaccination against ND is the only intervention that protects chicken from Newcastle disease.

Commercially available vaccines for the control of ND are effective but require the cold chain during storage and transportation to end users.  As such they are not suitable for small, multi-aged scattered free ranging chicken in rural areas where cold chains are rarely available.  In addition, although commercial vaccines are ideal for large chicken rearing facilities, their  packaging in large number of doses makes them unsuitable for farmers with smaller flocks due to wastage and hence expensive for the rural indigenous chicken farmers.

Rural production systems have not been conducive for vaccination since they are viewed as low input systems.  Additionally, backyard chicken rearing is controlled by women who often may not have access to extension agents for various reasons.  Most of the 32 million poultry  reared in Kenya are backyard chicken and the potential for their role in poverty alleviation is untapped.  A market ready backyard chicken is currently retailing at  Ksh 1,000 and there is growing demand especially in urban centres where these birds are increasingly competing with commercial broilers in the market.  Vaccination of these birds has the potential to greatly improve their productivity and increase numbers reaching market weight.  Vaccination of backyard chicken also provides an opportunity to invest in other management activities such as housing, feeding and other disease control measures for improved growth rates.

The objectives of this project was to identify, validate and commercialise a new vaccine appropriate for the Kenyan indigenous (backyard) chicken production systems,  which is easy to distribute in the rural areas in appropriate packaging without the need for a cold chain.

I-2 ND vaccine Background

The Australian Centre for International Agricultural Research (ACIAR) commissioned workers at the Virus Laboratory in the University of Queensland to produce a seed virus similar to ND commercial strains that could be made available without cost to laboratories in developing countries.  In 1999 forty-five isolates of avirulent ND were examined for effectiveness, safety and ability to spread. The most promising of these isolates were checked for thermostability and the more resistant isolates selected for enhanced heat resistance. The result was strain I-2, which was amplified in eggs from a disease free flock to form a master seed. The seed was tested for safety and for freedom from bacterial contamination.

Strain I-2 has undergone laboratory tests in several countries (Mozambique, Tanzania, Vietnam) and has proved to be protective against local virulent strains of ND virus. In Vietnam it has been officially recognized as the ND vaccine for local chicken, after extensive laboratory and local trials. In Tanzania it has given protection to rural chicken for at least two months after vaccination. Results from field trials in Mozambique indicate that I-2 ND vaccine provides approximately 80% protection in the face of an outbreak, when given every 4 months via eye drop.

ND vaccine of acceptable standard has been successfully produced from strain I-2 ND master seed at the Kenya Veterinary Vaccine Production Institute. The vaccine was produced in eggs, which are not specific-pathogen-free, but which come from a flock that is regularly screened for key poultry diseases. It has been produced and stored in liquid form, and suitably diluted in a protective solution such as 1% gelatin. The thermostable vaccine is best administered via eye drop. The I-2 vaccine can retain its protective ability for 8 weeks at 28°C when in freeze-dried form and stored in the dark.  Results from trials in Kenya have shown that I-2 ND vaccine provides 62% protection against Newcastle disease virus in chicken under a free ranging system.  As such we recommend I-2 ND vaccine for the control of Newcastle disease as a means of enhancing food security and nutrition among rural communities.


Summarized benefits of I-2 ND vaccine

1.      It is thermostable
2.      It can be administered via eye or nose drop, oral drench, or drinking water; mixed with certain feeds or by injection ;
3.      Its ease of administration makes it suitable for use by farmers;
4.      The vaccine strain can be transmitted by contact from vaccinated to non-vaccinated birds;
5.      It is avirulent and can be safely administered to chickens of any age from day-old to adult ;
6.      Its biological safety is superior to that of other living ND vaccine strains such as B1 or La Sota
Last Updated on Wednesday, 03 August 2011 09:54
 


   

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