Newcastle disease is a highly contagious and devastating viral disease of
poultry that distributed worldwide causing large economic losses in the poultry
industry. Although vaccines are being used to control the disease, there is no effective
antiviral drug used for the treatment of infections. The aim of this study is to test
garlic oil for its antiviral activity against Newcastle disease virus. Garlic oil was
incubated with the virus (LaSota strain) for 1 hr and 24 hrs and its antiviral effect was
determined by performing hemagglutination and RT-PCR tests to detect viral surface
proteins and viral genome, respectively. In addition, the toxicity of garlic oil was
determined on the living organism by injecting it into chicken embryos with or
without the virus. The results showed that this product played a role in the reduction
of virus effectiveness through the destroying of viral surface receptors as well as the
reduction of gene amplification as compared with the control group that included the
treatment of the virus with a saline solution (phosphate buffer saline), which gave
opposite results. In addition, there was no antiviral toxicity on the living organism
since the injected embryos with the oil alone or the oil with virus were healthy and
closely resemble those that have not been injected with anything. In comparison, the
embryos that were injected with the virus only showed clear pathological signs that
did not appear in the other groups containing the oil. These results suggest that garlic
 oil would be a good potential antiviral and probably will have a role to eliminate the
disease.