Review of Newcastle Disease control with emphasis in vx protocol

Biko M. Gadaga
Division of Veterinary Technical Services
D&R Branch, Central Veterinary Labs
Box CY551, Causeway, Harare
[email protected]
Opening remark
“Man, despite his artistic pretensions, his sophistication and
many accomplishments, owes the fact of his existence to a
six-inch layer of topsoil and the fact that it rains.”
Role of backyard poultry
*55% of SHF own cattle, over 70% shoats & 80%
chickens which play a complementary role to cattle incl.:
Health& well being – protein source and contain all
essential AA , vitamins&minerals. Eggs provide approx. 11.5
%of daily protein & 5% of daily energy requirements,
liquidation for grain, high quality manure for veg. gardens
 Gender biased- up to 60% women& children own & care
 Education- disposal for fees, books & incidentals
 Environ. Impact- minimum as they are scavengers
* Up to 1/3 of Zims poultry pop. Sector 3&4 (village
type/backyard/low biosecurity) note: Av. for Africa + 70%
Importance of Newcastle Disease
*ND is the most important disease of poultry in Africa & Zimbabwe
As it has potential to wipe out entire flocks
70-80% of annual losses are due to ND
Control could result in a 42% increase in production
Potential to incr. HH income by 80%.
But this is further complicated by:
 In ND endemic areas, the disease is generally well-recognised by farmers &
this discourages them from investing time & money in improving the
standard of their poultry husbandry
 Resource poor people least likely to take risks, as a result, adopt new tech
only once they are sure of an adequate ROI (time&$)
 Dev. partner funded projects have controlled activities which usually lack
cont. This lack of sustainability may be due in part to..
Overview of ND control
The control of ND in the family sector, as in the commercial sector,
requires a multifaceted approach. In the commercial sector, ND
control consists of (Alexander, 1997):
 International control policies – as per OIE standards
 National control policies – as per Animal health act
 Biosecurity at the farm level - sanitation and security practices
 Vaccination
Why vaccinate:*Primarily for Disease control
*Principle of vaccination : to elicit an immunological response
against the virus in a way that does not cause the disease.
 Reduce economic losses(egg & meat production)
 Hamper diffusion of virulent strains
 Tool for disease eradication
Types of vaccine: Traditional : Live virus: Hitchner B1, F, La Sota
Clone 30, 6/10, VG/GA, V4, I2
Inactivated: Mukteswar
New generations
Recombinant (FP, HVT) with subunits
Current protocol: Sector 3&4
*One/Two rounds of avirulent thermotolerant I2 vaccine sourced
from CVL during the dry winter season i.e.- Apr-Jun then Jul-Sep
 Note strategic as farmers are not busy in their fields &high
incidents of outbreaks occur in winter. Dry season favours movt of
chickens to mkt, exchange of animals between villages & regions
 Flocks are scattered, multi-aged and usually unhoused
 CBV concept allowed the overcoming of extension challenges
with realisation of community ownership& op. sustainability
 In extensive flocks, economic losses associated with outbreaks are
often alleviated by: self-consume, salvage slaughter &sale
The same practices enhance the spread of the disease in the area
General review (SWOT analysis)
 Community based therefore Relevant, Ownership?,SustainableEffecient.
 Local vaccine production therefore cheaper
 Competent DVS ext. staff and CBVs
 Donor driven, inconsistent labelled & min. ext. staff coop.
 Little to NO commercial poultry producer participation
 Lacks scientific evaluation tool(effectiveness unknown)
 Lacks further farmer education
 Poor I2 Vaccine packaging losses, dilution problems
General review cont.
 Improved perception on of role of poultry as a sustainable
enterprise to alleviation poverty& major protein source
 Backyard poultry is perceived healthier, tastier(Organic)
 Advent of Conservation agriculture (CA) &climate change
 High grain and oilseed prices
 Registration and commercial I2 production
 Prioritization of intervention/emergency mitigation in crops
 Funding in livestock targeted towards cattle
 Ownership gender biased with min. part. of heads of HH
 Globalisation , advent of cheap GMO fed imports
Review cont.
Experience has shown that a sustainable ND control prog. has
4 essential components (Alders et al., 2001):
 an appropriate vaccine and vaccine technology;
 effective extension materials &methodologies that target
veterinary and extension staff as well as CBVs & farmers;
 simple evaluation and monitoring systems of both technical
and socio-economic indicators;
 economic sustainability based on the commercialisation of
the vaccine &vaccination services & the marketing of surplus
chickens and eggs.
Scientific review
*Vaccination might be an important tool only if applied
adequately&concomitantly with:adequate bio-security measures&
verification sys that detect & eliminate the coz of efficacy reductn
 Humoral immunity, Ab against F &HNproteins is of paramount
importance for the protection of ND virulent strains
 To guarantee vaccination MOST individuals in the vaccinated
population should have adequate protection thus transmission of
the ND virus might be interrupted only if > 85% shows an Ab
titers ≥ 1:8 (Boven et al., 2008) .
 The protection of the “group” of birds in a farm is adequate only if
the average Ab titers of the farm is not <1:8 &if at least 75% of the
animals have Ab titers not <1:32 (Cameron . 2007)
Scientific review cont.
The optimal protection is obtained through the use of a
live vaccine followed by an inactivated &the ideal interval
between two interventions should be of at least 3wks
Whenever Ab titers are considered not protective, it is possible to
vaccinate with live vaccines
In a low risk situation, (no circulation of highly pathogenic virus) a
minimum vaccination protocol with the predominant use of live
vaccines might be adequate.
In a high risk situation and in emergency situation, the use of
inactivated vaccines is obligatory to guarantee high Ab titers
Outbreak origin patterns; generally 62% from backyard to
backyard system, backyard-commercial 13% &com-com 25% .
Vaccine Selection considerations
The selection criteria of a ND vaccine for use in backyard poultry:
•Ease of use
•Thermostability (where cold chain maintenance is a challenge)
o Continue CBV approach i.e. Recruit & Retrain
o Expand ownership to ext& other gvt staff. i.e.- incorporate in
workplans wholesome, AI/ND surveillance& vaccination
o Commercial producers should take lead as major stakeholder
o Repackage I2 vaccine into convenient 200/100 doses
o Design scientific M&E tool which inc. social aspects
o Conduct further field trials incl. Field strain typing
o Inc. other dzz poultry prod. aspects in CBV curriculum
o Maintain contacts with international institutions
Only dead fish follow the flow.
• Participatory approach the in thing thus there is need for a
consistent program on DVS calendar with/out donor support
• CBV concept is sustainable overally and this opportunity
needs to be exploited and extended to most disease
vaccination and surveillance other than AI and ND.
• Instead of limiting to CBV concept there is room to expand it
to a Community Based Animal Health worker
i.e. a first line to disease management
The Directorate of DVTS in particular Drs Makaya and
Nyika for affording me the opportunity to travel to
AU/PANVAC and maintaining links with renowned
continental and international institutions
 Resource personnel at AU/PANVAC particularly Ms
Ethel Chitsungo and the team from Padova.
 Above all, all present at this LWG presentation.

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