Abstract
Velogenic strains of Newcastle disease virus (NDV) were isolated from field outbreaks. ELD50 of the VNDV was determined
at 10-5.33. La Sota strain and Incomplete Freund’s Adjuvant (IFA) were inoculated in adult chicks to raise hyper immune
serum. The serum was purified and used to reduce the morbidity and mortality in experimentally infected broiler chicks with
Newcastle disease virus (NDV). 120 day-old broiler chicks were divided into four groups i.e. A, B, C and D. At 14th day of
age, the chicks were infected with velogenic field isolate of Newcastle disease virus (ELD50 = 10-5.33/0.1mL) and two hours
post infection the birds were passively immunized with HIS @ 2mL, 3mL and 6mL, in group B, C and D, respectively, while
group A was kept as control. Chicks received 2mL HIS exhibited severe respiratory and enteric signs of Newcastle disease,
while chicks received 3mL and 6mL HIS were anorexic in early days and on 10th day post inoculation (DPI) they were
recovered. Gross lesions in infected birds were hemorrhages in trachea, proventriculus and intestine, and congestion in
infected lungs. Histo-pathological examination showed epithelial sloughing, congestion of blood vessels in group A, mild
tracheitis and alveoli of lungs filled with exudates along with lymphocytes in group B, mild lymphocytic infiltration in group
C, while trachea and lungs showed no significant change in group D. Higher range of GMT values were observed in group D
while low range of GMT values were observed in group A. It was concluded that HIS against NDV can be used to decrease
the morbidity and mortality rate in experimentally infected birds.
