VACCINATION AND COMPARISON OF THE POTENCY OF NEWCASTLE DISEASE VACCINE STRAINS I2 AND LA SOTA IN RURAL CHICKENS IN PLATEAU STATE, NIGERIA
VACCINATION AND COMPARISON OF THE POTENCY OF NEWCASTLE DISEASE VACCINE STRAINS I2 AND LA SOTA IN RURAL CHICKENS IN PLATEAU STATE, NIGERIA
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Date
2009-02
Authors
MUSA, USMAN
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Abstract
Newcastle Disease (ND) has been recognized for a long time as one of the major
production constraints to rural poultry. Management systems, thermoliability,
maladministration of vaccines and lack of extension services have been suggested as
possible causes of outbreaks, spread and maintainance of ND. A study on
management systems in rural household chickens in Plateau State was, therefore,
conducted in 32 rural households of four Local Government Areas (LGAs) involving
1,240 households using a structured questionnaire. Also studied was ND antibodies
and field vaccination with ND vaccine strain I2 (NDVI2) on 1,208 chickens raised
under traditional management system. Thermostability of NDVI2, vaccination trial
and comparative immunogenicity tests using NDVI2 and La Sota administered via
different routes and vaccine carriers were investigated. The cost benefit of ND control
using NDVI2 via intraocular (i/o) route was estimated. The ND antibodies in rural and
commercial chickens were evaluated using haemagglutination inhibition (HI) tests
and the vaccines were titrated using embryonated chicken eggs. Diseases were the
main (83.2%) causes of losses of rural chickens followed by preying (8.85%) and
herbs were main remedies used for managing ND. Out of 1,208 sera tested, 627
(51.9%) had detectable antibodies to ND virus, but only 170 (14.1%) of the chickens
had a protective HI antibody titre of ≥ 4 Log2. About 1,041 (86.2%) of the chickens
sampled were at risk of suffering from clinical ND. In the field, NDVI2 administered
by i/o route gave higher geometric mean titre (GMT) of 8.3 + 1.6 Log2 and 92%
protection rate than when administered through drinking water (dw) with GMT of 3.4
+ 0.6 Log2, yielding a 46% antibody protection rate. Reconstituted and lyophilized
NDVI2 vaccines maintained a minimum infective dose of 6.8 Log10 and 8.4 Log10 for
3 and 35 days, respectively from an initial titre of 10.2 Log10. Reconstituted NDVI2
lost 3.4 Log10 titre after exposure at room temperature (RT) for 3 days. Lyophilized
NDVI2 lost only 1.8 Log10 titre after exposure at RT for 35 days. NDVI2 or ND La
Sota vaccines administered through commercial feed, parboiled sorghum, parboiled
sorghum coated with gum Arabic and untreated sorghum gave little protection (0 to
22%) to birds when challenged with velogenic viscerotropic ND virus. The financial
losses due to ND outbreak in unvaccinated flocks in terms of the value of birds and
eggs amounted to ₦1,250,505.9 and losses avoided following vaccination were
₦10,296,264. The benefit cost ratio arising from adopting NDVI2 via i/o route for the
control of ND in rural chickens is 7.2. It was concluded that the prevalence and risk of
ND in rural chicken are very high. The NDVI2 or NDV La Sota vaccines can protect
commercial and rural chickens vaccinated through i/o, im or dw routes, while feeds
were not suitable as vaccine carriers. In the field, ND vaccination with NDVI2 via dw
route may not be appropriate but the benefits derived in the use of NDVI2 via i/o route
were greater than the cost of the ND outbreak in unvaccinated flocks.
Description
A DISSERTATION SUBMITTED TO THE POSTGRADUATE SCHOOL
AHMADU BELLO UNIVERSITY ZARIA, NIGERIA, IN PARTIAL
FULFILMENT OF THE REQUIREMENTS FOR THE AWARD OF DEGREE
OF DOCTOR OF PHILOSOPHY (Ph.D) IN VETERINARY MEDICINE
DEPARTMENT OF VETERINARY SURGERY AND MEDICINE
FACULTY OF VETERINARY MEDICINE
AHMADU BELLO UNIVERSITY
ZARIA NIGERIA
FEBRUARY, 2009
Keywords
VACCINATION,, COMPARISON,, POTENCY,, NEWCASTLE,, DISEASE VACCINE STRAINS,, PLATEAU STATE, NIGERIA