Background and Aim: Equine herpesvirus-1 infection in horses causes a wide range of manifestations affecting the respiratory tract. The virus can cause serious economic losses through sporadic abortion in pregnant mares, perinatal death, respiratory disease in young foals. This study was designed to prepare inactivated equine herpesvirus-1 (EHV-1) vaccine using both 0.005 M binary ethylenimine (BEI) and 0.0006% formaldehyde (FA) to decrease the use of BEI and provide a good immunological response. The efficacy, safety, and duration of immunity of the prepared inactivated EHV-1 vaccine were evaluated.
Materials and Methods: The prepared FA/BEI-inactivated EHV-1 vaccine was adjuvanted with Alhydrogel and then evaluated by inoculation into guinea pigs, followed by comparison with the commercial inactivated EHV-1 vaccine. These two vaccines were evaluated by testing the safety and immunogenicity in horses classified into two groups. Group A was vaccinated with two doses of the prepared vaccine at a 4-week interval, while Group B was vaccinated with two doses of the commercial vaccine only. Anti-EHV-1 antibodies were detected in horse serum using enzyme-linked immunosorbent assay (ELISA) and virus neutralizing test (VNT).
Results: Regarding the time required to inactivate EHV-1 vaccine, this was decreased using 0.005 M BEI and 0.0006% FA from 24 to 8 h. ELISA in Group A horses demonstrated a significant increase in EHV-1 antibody titer at 2 weeks after the booster dose compared with that for the pre-booster one, from 485 to 855 antibody titer, which then peaked at 1240 in the 3rd month post-vaccination; after that, it began to decline gradually until the 6th month. Meanwhile, in Group B, the ELISA reading increased from 420 to 790 and then peaked at 1215. The VNT mean in Group A increased from 1.1 to 2.5 within 2 weeks after administration of the booster dose, while in Group B it increased from 0.8 to 2.1. Moreover, ELISA in Group A pigs indicated mean antibody titers at the 3rd week post-inoculation of 576 for Group A and 554 for Group B.
Conclusion: The inactivated EHV-1 vaccine, with fewer chemicals, was prepared in a shorter time. It is safe and also more potent to protect horses for up to 6 months against EHV-1 infection than the commercially produced vaccine.
Equine herpesviruses (EHV1 and EHV4) are essential in horses. Repeated cases of infection and abortion in mares who have regularly vaccinated impetus us to determine to investigate the humoral immune response after post-vaccination with the same inactivated vaccine and the best vaccination protocol. Twelve healthy susceptible horses were divided into four groups (3 horse /group). The first group was vaccinated I/M with inactivated Equine Herpes (type 1 and 4), where each horse was inoculated with a single dose (2ml/ dose /horse). The second group was vaccinated with inactivated Equine Herpes (type 1 and 4) then a booster dose after two months. The third group was vaccinated with inactivated Equine Herpes (type 1 and 4) followed by two booster doses at two months intervals. Three horses were kept as a negative control in the fourth group. Serum samples were tested for the EHV and antibodies using virus Neutralization Test (VNT) and ELISA; it was found that VNT against EHV-1 indicated that the neutralizing antibody titer value ≥ 4 fold titer rise had been demonstrated at 28th-day post-vaccination for all vaccinated horse groups, it was demonstrated that the vaccinated horse group (1) indicated the significant greater titer values compared to other vaccinated groups and showed protective titer value till the end of the experiment (6 months post-vaccination), There is an agreement in titer values between ELISA and VNT tests for EHV was observed, but it could not reveal the same antibodies, where the ELISA measures antibodies against EHV1-4. It was concluded that the single-dose vaccination protocol was more appropriate for horse vaccination than other vaccination protocols.
Rift valley fever is an arthropod-born, multispecies zoonotic viral disease. Control of RVF disease depends mainly on vector control and vaccination of susceptible animals. The present work aims to detect the correlation between Rift Valley Fever Virus (RVFV) neutralizing antibody titers in vaccinated sheep using Serum Neutralization test as in vitro test and effective dose fifty in vaccinated mice as in vivo potency test and determine if they can be alternative to each other. In this work,17 inactivated RVFV vaccine batches were evaluated, applying SNT for serum samples of vaccinated sheep and ED50 in vaccinated mice. The two models of tests showed compatible results, where the same 14 vaccine batches showed satisfactory results [(SNT >1.5) and (ED50 less than 0.02)], while the other three batches revealed unsatisfactory results in both two tests. Statistical analysis of results using Wilcoxon’s test was (0.0001), indicating a significant correlation between the tests so it could be recommended to depend on SNT instead of mice inoculation in the evaluation of RVF vaccine to reduce the numbers of animals being used and to avoid the possible public health hazard.
Lumpy Skin Disease (LSD) is a vector born disease of cattle, caused by Lumpy Skin Disease Virus (LSDV), there is antigenic relationship between LSDV, Sheeppox virus (SPPV) and Goat pox virus GTPV within a genus Capripoxvirus, accordingly it can be used homologous or heterologous Capripoxvirus strains for vaccination of cattle against LSD. This study compare the efficacy of live attenuated Neethling LSDV vaccine and live attenuated Romanian SSPV Vaccine against recent circulating LSDV field isolate. The evaluation was done in calves as the main host of LSD, through using three different batches for each vaccine type. Experimental calf groups were vaccinated with vaccines batches, and after 21 days serum samples were collected for evaluation of humoral immune response by using SNT and commercial ELISA technique, then the vaccinated calves were challenged by virulent LSDV field isolate. The results of SNT for vaccinated calves by LSDV vaccines indicated mean neutralizing antibody titer 1.2, 1.6 and1.5 log10 for the batches 1, 2 and 3 respectively, while vaccinated calves by SPPV vaccines indicated 1.05, 1.05 and 1.5 log10 for the batches 1,2 and 3 respectively; the ELISA mean sample to positive (S/P) percentage for the vaccine batches 1, 2 and 3 of LSDV were 40, 45 and 42% respectively and for SPPV vaccine batches 1,2 and 3 were 35, 37 and 40 % respectively, the challenge test indicated mean difference titer for the groups of calves vaccinated with LSDV vaccine were 4.2, 4.5 and 3.8 log10 and for groups vaccinated with SPPV vaccine were 2.6, 2 and 2.65 log10 respectively, it was concluded that potential using of Neethling LSDV vaccine against LSD is superior for combating and prevention of the lumpy skin disease.
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