Comparative efficacy of various antiviral agents against avian influenza virus (Type H7N3/Pakistan/2003)

Highly pathogenic avian influenza (H7 type) is of greater importance due to its economic impact and public health significance. Drugs available to vanish this pathogens are very limited and having high prices. Therefore a study was planed to check the comparative efficacy of the Herbs' extract as compared to the standard available drug in the market. There were used three different concentrations (2%, 4% and 8%) of each of amantadine HCl, extracts of fresh leaves of opuntia herb, papaya and dried powdered leaves of green tea in distilled water and were evaluated for their antiviral activity, by injecting through chorioallantoic sac route into 10 days old live embryonated broiler chicken eggs. Group A is negative control with no haemagglutination activity and group B as positive control with positive Haemagglutination activity. For each drug to be tested, 40 eggs were assigned to 8 groups (i.e. A, B, C1, C2, C3, D1, D2, D3) with 5 eggs in each group. Embryonated eggs in each of C1, C2 and C3 subgroups were treated only with 3 different concentrations of each compound to evaluate toxicity respectively. Whereas embryonated eggs of SUB-GROUPS D1, D2 and D3 were treated with suspensions of three different concentrations of each compound with 4HA titer of Avian Influenza Virus (AIV) type H7N3/Pakistan/2003, to check antiviral efficacy respectively. Positive and negative controls were also run side by side under similar experimental conditions. In case of amantadine HCl out of 50, 500 and 1000 mug/ml concentrations, only 500ug/ml was found to be an ideal concentration, as in addition to stop virus growth it also did not kill the embryos. In case of Opuntia dellinii all the 3 concentrations used were not toxic for embryos, but antiviral effect was observed only at 4g and 8g/100ml concentrations. Green tea extract was found to be effective against AIV only at 8g/100ml concentration with no damage to chick embryos. Papaya leaves extract as a whole failed to check virus replication at all the three concentrations used in this experiment i.e. 2, 4 and 8g/100ml. All these dose levels were not lethal for chick embryos.