In vitro Adoption and Propagation of High Pathogenic Avian Influenza (HPAI) Virus Subtype H5N1 in non-avian Host System

The paradigmatic, fatal and devastating ailment called avian influenza or bird flu is a highly contagious viral disease caused by type A influenza virus, It primarily affects the respiratory, digestive and/or nervous system of chickens, turkeys, guinea fowls and other avian species and less commonly pigs and other species of mammals including human. In India, The first pandemic outbreak of Avian Influenza was reported during 2006. In this study, we selected an isolate of high pathogenic avian influenza (A/Ck/Jalgaon/India/12419/2006) H5N1 virus and propagated in chicken embryo fibroblast. Later this virus was adopted and propagated in Madin-Darby canine kidney cells (MDCK) and Vero cells. Infected non-avian cells with an avian virus shown cytopathic effects like rounding, cytoplasmic elongation, syncytia formation and later stages fluffing from the attached surface. The harvested virus suspension shown increased haemagglutination titre (HA) than viral suspension from chicken embryo fibroblast culture and the presence of virus was confirmed by reverse transcriptase-polymerase chain reaction (RT-PCR). The obtained result reveals that virus had capacity to adopt for the invitro culture and propagate in non avian host cells with higher titre. This infers the chance of virus to cross the host barrier and probable chance of infection in human being

Evaluation of immuno efficiency of hemorrhagic septicemia vaccine strain (vaccine seed)

Objective: To compared seed culture of hemorrhagic septicemia (HS) bacteria which was used to produce vaccine for its antibody induction efficiency before and after passaging in natural host (calf) using laboratory animals. Methods: Serial dilution of virulent bacteria was injected in to mice which were immunized with HS vaccine which was obtained from seed bacteria before and after back passaged in calf. Ratio of survived and dead was calculated by Reed-Meunch hypothesis and the LD50 value for each vaccine trial groups were calculated. Results: The immunological study revealed that vaccine prepared from back passaged seed culture showed greater improvement in its immunopotency than seed vaccine (before back passage). Around 200 mice were used to study the immuno efficiency of vaccine. Each mouse was from the same source, which were free from the Pastuerella infection previous to expose to trial infection. The same broth culture of HS was used to induce infection in mice in both trials (vaccine before back passage and vaccine after back passage). The 0.2 mL of broth dilution from 10−1 to 10−10 was used, as dilution increases, death rate decreases. It indicates the minimum load of bacterium is required to induced infection. Conclusions: Obtained results revealed that back passaged vaccine seed HS bacteria in its natural host had provided better immune efficiency to the culture than laboratory stock culture, and this findings recommended that regular annual back passage was mandatory for the vaccine seed culture of Pastuerella multocida bacteria for better establishment of immune potent vaccines