Locally produced inactivated oil emulsion newcastle disease (ND) vaccine

The Biologics Vaccine Production Laboratory of DA-RFU 7 [Department of Agriculture - Regional Field Unit - Central Visayas, Philippines] has been licensed by the Bureau of Animal Industry (BAI) to produce and manufacture locally inactivated oil emulsion ND vaccine. Several in-house researches and field experiments on the efficacy of the produced vaccine has been conducted and gave positive results. However, said studies were limited within Region 7. The need to further test the efficacy of said vaccine against ND in other regions was inevitable. To address this concern, Cadeliña et al. (DA-RFU7) assessed the efficacy of the DA-RFU7 - produced inactivated oil emulsion ND vaccine from June 2006 to July 2007 in Region 6 (Iloilo covering 8 municipalities), 7 (Amlam, Oriental Negros covering 7 barangays [villages]) and 10 (Bukidnon covering 5 municipalities). The focal sites were identified based on the poultry population in the region, disease situation, and LGU participation in the program. The protective titer of chickens vaccinated with the DA-RFU7 locally produced vaccine was determined through Hemagglutination Inhibition (HI) technique and challenge test. A total of 1,500 head of upgraded native chickens (500 head/region) were randomly selected as experimental animals. Wing bands were placed on the chicken for identification purposes. Pre- and post-blood collections were conducted and all serum samples were examined through HI technique. The study revealed that there was an increasing antibody response in chicken vaccinated with the DA-RFU7 locally produced vaccine during the 1st and 2nd vaccination. Pre-blood collection in Region 6 reflected presence of antibody in the titer in most of the serum samples examined. Geometric mean titer (GMT) ranged from 27.54 to 61.09 because most of the research cooperators in the area were vaccinating their flocks with commercially available live vaccines. At 3 weeks and 6 months post-vaccination with the DA-RFU7 ND vaccine, there was a significant increase in the GMT from 52.48-275.42 to 71.42-266.07. At 3 weeks post-2nd vaccination, GMT remained at its protective level. Region 7 showed low antibody titer at pre-blood collection ranging from 5.58 to 14.65, since most poultry raisers were not regularly vaccinating their chickens against ND. At 3 weeks post-vaccination, GMT results showed significant increase, however, at 6 months post-vaccination, GMT results decreased in some areas. At 3 weeks post-2nd vaccination, GMT remained at its protective level. Pre-blood collection results in Region 10 [Northern Mindanao, Philippines] also showed low antibody titer. Most of the poultry raisers were not regularly vaccinating their chickens against ND except in fighting cocks. At 3 weeks post-vaccination, GMT results showed significant increase but at 6 months post-vaccination, GMT results decreased in some areas. Six months after second vaccination was administered to the experimental flock. At 3 weeks post-2nd vaccination, GMT remained at its protective level. The vaccine can protect free-range chicken against ND with 100% survival rate while all the unvaccinated chickens died. Both the control/birds and the vaccinated were inoculated with 0.5 ml Escario strain challenge virus and were observed for 14 days. The vaccinated chicken remained healthy and showed no ND infection during the 14-day observation period, while all the control birds showed weakening of the legs, loss of appetite, greenish white feces, and eventually died within the 5-day observation period. Necropsy conducted in the control chickens showed remarkable infection of ND on lesions in both the large and small intestines, trachea, and proventriculus. Using simple economic analysis, if 1,500 chickens were not vaccinated and were affected by ND, PhP 180,000 would have been lost, as every kilo liveweight was valued at PhP 120. On the contrary, if these 1,500 head were vaccinated with the DA-RFU7 ND vaccine, they would only incur an additional cost of PhP 4,800 for the vaccine period at PhP 1.60/dose given twice during booster vaccination and revaccination. Therefore, the DA-RFU7 ND vaccine is highly recommended for implementation as booster for breeders and layers for the prevention and control against ND.