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The spread of duck hepatitis virus (DHV) in Egypt with its’ most prevalent genotypes (1 and 3) causes vast economic losses in the duck industry despite the regular vaccination with live attenuated vaccines. However, the use of live-vaccines is considered a potential risk for the non-vaccinated birds due to the viral shedding from vaccinated populations. The current study aimed to evaluate the protective efficacy and safety of two inactivated monovalent and one bivalent vaccines against DHV 1 and 3 genotypes. The inactivated monovalent (DHAV-1, DHAV-3) and bivalent (DHAV-1+3) vaccines were produced by using Montanide ISA 70 oil as an adjuvant. Three groups of 4-week-old ducklings (n=50) were vaccinated with one of the three vaccines, respectively. One group of ducklings was used as negative control (n=25). The immune-response of the vaccinated groups was measured by Virus Neutralization Test and expressed with Neutralizing Indices (NIs). The NIs for the bivalent vaccine group (5.6 and 5.4) were higher compared to the monovalent vaccine groups (5.0 and 4.7). In conclusion, the use of inactivated bivalent DHV vaccine could produce higher protective efficacy compared to the monovalent DHAV-1 and DHAV-3 vaccines.

Equine influenza is a highly contagious viral disease, specially among 1-5 years old naive horses. Vaccination is considered the best way to control the disease spread and outbreaks. Although foals are the main animal used for evaluation of equine influenza vaccines, guinea pigs were chosen as an alternative model in the present work, as they have a negligible antibody titer against equine influenza virus and are cheaper and easier to handle than foals. Five equine influenza vaccine batches were evaluated in two animal models, foals and guinea pigs, by injection of two doses/animal with 4 weeks apart using 2 mL/animal/dose and evaluation of immune responses by hemagglutination inhibition test and enzyme-linked immunosorbent assay. On the 7th week post vaccination, equine influenza antibodies titers reached maximum values of 9-10.2 and 8.7-10 hemagglutination inhibition units for foals and guinea pigs, respectively; sample/negative ratios were 0.126-0.464 and 0.128-0.445 for both animals, respectively. The use of guinea pigs as an animal model for the evaluation of equine influenza vaccines could be recommended instead of foals.