Abstract 

Background

Newcastle disease  is a highly contagious disease of birds caused by Paramyxovirus. Birds mostly affected by Paramyxovirus virus includes; chickens, turkeys, geese, ducks and guinea fowls. Newcastle disease however, remains a worldwide problem. There are three major strains of Newcastle disease virus and they are velogenic, mesogenic and lentogenic strains respectively. These viral strains reflects the severity of the disease pathotypes. In the medical laboratory,  these viral strains are classified according to the rate of chicken embryo mortality which is measured by the Mean Death Time (MDT) of the embryos inoculated with the Newcastle disease virus by the allantoic cavity route.

Methodology 

Aqueous and ethanol extracts of Mangifera Indica and Thymus Vulagris plants were prepared and used for the study. Eight embryonated eggs were used for each extract. Out of the eight eggs, four were used for the aqueous extract plus Newcastle disease virus inoculation at 0 hour interval with two eggs and 2 hours interval for the other two eggs. The remaining four eggs was used for the ethanol extract plus virus inoculation at 0 hour interval with two eggs and 2 hours interval of virus and ethanol extract using the remaining two eggs. These groupings were applied for the two plants used for the research study. 

Results

Thymus Vulgaris inhibited Newcastle disease virus giving a positive control of 9.0. The aqueous extract of Thymus Vulgaris gave a mean log2 reciprocal  of HA titre value of 4.0 and 5.0 at 0 and 2 hours while the ethanol extract of the same herb gave a mean log2 reciprocal of HA titre value of 5.0 and 6.5 at 0 and 2 hours respectively.  The aqueous extract of Thymus Vulgaris gave a percentage inhibition of 55.56% and 38.89% at 0 and 2 hours while the ethanol extract of the same herb gave a percentage inhibition of 44.44% and 27.78% at 0 and 2 hours. The aquoues extract of Mangifera Indica gave a mean log2 reciprocal of HA titre value of 8.5 and 6.0 at 0 and 2 hours while the ethanol extract of the same herb gave a mean log2 reciprocal of HA titre value of 6.5 and 8.0 at 0 and 2 hours. The aqueous extract of Mangifera Indica gave a percentage potentiation of 46.55% and 3.45% at 0 and 2 hours while the ethanol extract of thesame herb gave a percentage potentiation of 12.07% and 37.73% at 0 and 2 hours. 

Conclusion

This research was carried out to thoroughly investigate and establish the antiviral effect of  Mangifera Indica (Mango leaf) and Thymus Vulagris (Thyme) on Newcastle disease virus.  Thymus Vulgaris was found to inhibit the virus while Mangifera Indica potentiated the virus. This research study can help create awareness and knowledge on the benefits of Thymus Vulgaris antiviral effects on Newcastle disease virus.  Therefore, there is urgent  need for pharmaceutical companies and policy makers to extract the active ingredients of Thymus Vulgaris, in order for it to be used in producing antiviral drugs for the cure of Newcastle disease virus. This drugs can help reduce the risk of Newcastle disease among poultry flocks and poultry workers thereby restoring flocks and egg production for human consumption.