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PROJECT TOPIC:  ASSESSMENT OF NEWCASTLE DISEASE VIRUS ANTIBODIES AMONG BIRDS
Department:  Microbiology
AMOUNT:  10,000
FORMAT:   MS WORD
PAGES:  93
 
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Newcastle disease is a contagious disease of birds and is the greatest constraint to the development of rural poultry production in Nigeria and most developing countries. The only effective means of control is vaccination which is not properly carried out in Nigeria. Therefore, this project determined the prevalence rate of Newcastle disease virus (NDV) in local chicken in the Federal Capital Territory, Abuja, Nigeria. About 5 mL of blood was collected from each of 200 chickens at the point of sale by exsanguination and sera obtained were analyzed using Haemagglutination Inhibition (HI) test to determine the prevalence of NDV. Of the 200 samples screened 34 were positive for HI antibody to NDV giving a prevalence rate of 17%. The prevalence rate obtained in this study is significant  and indicates endemicity of the disease. There was no statistically significant  difference in the seroprevalence of NDV antibodies among the four markets studied. Further studies are required to determine the strains circulating for appropriate preventive and control measures.

1. Introduction

Newcastle disease (ND) is a highly contagious viral infection of avian species especially poultry caused by Newcastle disease virus (NDV), a Paramyxovirus called avian Paramyxovirus type 1 (APMV-1). Although other host species are usually susceptible, the disease has a significant economic impact on poultry production [1]. There are about nine strains of NDV which are distinguished on the basis of pathogenicity test [2].

ND is mostly caused by velogenic strains of NDV rather than mesogenic or lentogenic strains which about 80–100% and 25% mortality, respectively, from disease [3–5]. Overall, seropositive rate of 32.5% was reported by [6] for Sokoto State, Nigeria.

Reference [4] reported a prevalence of 3.2% for NDV in clinically healthy chickens in Nsukka area, Nigeria. Reference [7] reported a higher incidence rate (68.4%) of ND during the dry season against 34.6% in the rainy season and higher rate in the young (20.7%) against 12.1% in the adult. Newcastle disease can cause great mortality in birds without any clinical signs, sometimes reaching 100 percent in unvaccinated poultry flocks and even in vaccinated poultry [4]. This disease is endemic, causing huge economic loses to farmers and hampering growth of poultry industries in Nigeria, which has an estimated poultry population of 137.6 million, with backyard poultry population constituting 84% (115.8 million) and 16% (21.7 million) of exotic poultry.

There is no means of treatment for this disease except vaccination which is not effective as outbreaks are reported yearly in vaccinated chickens. Lack of data regarding the prevalence of this disease in most parts of Nigeria has made policy formulation on controls and prevention difficult. Therefore, this research was carried out to determine the prevalence of NDV in local chicken in the Federal Capital Territory Abuja, Nigeria.

2. Material and Methods

2.1. Study Area

This study was carried out in local chicken of different sexes in Kubwa and Lugbe, Abuja-FCT, Nigeria. Abuja is located on longitude 7°, 29′ East and latitude 9°, 4′ North. The annual rainfall is high which begins from April and ends in October. The mean maximum temperature is about 27.5°C [8].

2.2. Sample Collection

About five milliliter (5 mL) of blood was collected into a sample bottle containing ACD from each of two hundred (200) local adult chickens by exsanguination in Kubwa and Lugbe markets in Abuja, Federal Capital Territory, Nigeria. Efforts were made to prevent discomfort to the chickens. Sera were obtained by centrifugation and transported to the Avian Viral Research Unit, National Veterinary Research Institute (NVRI), Vom, Plateau State, for laboratory analysis.

2.3. Haemagglutination Inhibition (HI) Test

Antibody titer for NDV was determined from each serum sample using the OIE HI test protocol. Briefly, 0.025 mL of PBS was dispensed into all wells of a plastic 96-well microtiter plate (v-bottomed wells) and 0.025 mL of serum was placed in the first well. 0.025 mL of the positive control serum (with known HI titer) and negative control sera were added to two respective wells of the microtiter plates. With the aid of a multichannel micro pipette, twofold dilutions of the sera were made across plate (A1–A12). The last 0.025 mL was discarded and 0.025 mL of antigen containing 4 HAU was added to all the wells except row H which serves as back titration.

Newcastle disease virus (very virulent Kudus strain) was used as antigen. Back titration was carried out; thus, 0.025 mL of antigen suspension containing 4 HAU was added into each of the first two wells of row H (4 HAU control from H1–H6), and twofold dilution was made from H2 to the H6 and the last 0.025 mL was discarded in order to obtain 4, 2, 1, 0.5, 0.25, and 0.25 HAU. 0.025 mL of PBS and albumin was added in all wells of row H and mixed by tapping gently and plates were placed at 20°C for 30 minutes. 0.025 mL of 1% washed chicken-RBC was added to each well. Mixing was done gently by tapping and the plates were placed on the bench at 20°C for 30 minutes and observed for HI.

2.4. Data Analysis

Geometric mean of HI antibody titer (GMT) and percentages of detectable NDV HI antibody titer were calculated. The Statistical Package for Social Sciences (SPSS) Programme (version 13) was used to compare if there was any significant difference between the geometric means of the HI antibody titer.

3. Result

3.1. Seroprevalence of NDV in Local Chicken in Kubwa and Lugbe Markets

Result showed that the seroprevalence rate of NDV antibodies for Kubwa village market was 15 positive samples (30.0%), Kubwa Monday market had 7 positive samples (14.0%), Gaso Lugbe market had 6 positive samples (12.0%), and Sabo Lugbe Market had 6 positive samples (12.0%). The mean HI titer for the respective markets includes 5.1, 4.9, 5.0, and 5.5 (Table 1).

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