ANTIVIRAL EFFICACY OF GARLIC OIL AGAINST NEWCASTLE DISEASE VIRUS

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 control control observed in other hand, another study has evaluated the cytotoxicity and antiviral activity against Newcastle disease virus of ivermectin, a medication used to treat many types of parasite infestations such as scabies, head lice, strongyloidiasis; and ribavirin which is an antiviral medication used to treat RSV infection, hepatitis C, Lassa fever and severe cases of influenza. The study concluded that ivermectin has strong antiviral potential at 100μg/ml and higher but some concentrations were cytotoxic while ribavirin showed strong antiviral potential at all concentrations (9) . In the current study, the concentration of garlic oil which was 50μg/ml gave good results in destroying the virus without toxicity seen in the chicken embryos. A study suggested that fucoidan from Cladosiphon okamuranus exhibited antiviral activity against Newcastle disease virus LaSota strain, and represented a potential low-toxicity antiviral compound for the poultry industry . Another study revealed that ethanolic extracts of Acacia cyanophylla leaves, Moringa peregrina leaves, Eucalyptus camaldulensis fruits and Pistacia atlantica (leaves and stem) can inhibit Newcastle disease virus completely without causing death of the chicken embryo. However, the response of the viral-infected chicken embryos was different depending on the species of the medicinal plant, plant material concentration applied and the plant part. In addition, some plant extracts showed a dose dependent relationship with the degree of the virus inhibition, whereas other plant extracts showed some toxicity on the chicken embryo (11). The results of our study revealed that the current doses of garlic oil has not shown any toxicity on chicken embryos and eliminate the virus completely, and therefore, garlic oil would be a potential antiviral drug against Newcastle disease virus.