Although equine herpesvirus-1 (EHV-1) infection occurs throughout the world; causing various health problems within horse population such as respiratory disease, abortion and myeloencephalopathy, there is information shortage concerning the epidemiological situation of EHVs in Egypt. This paper is the first study of EHV-1 prevalence rate in Monufia province (as a model for other pro­vinces). During 2015, two hundred and seventy serum samples from EHV non-vaccinated horses were randomly collected from 9 centres of Monufia province. The indirect ELISA was used to detect the prevalence rate of the disease while assessment of the associated risk factors was conducted using univariate and multivariate logistic regression models. The results showed that EHV-1 infection was widespread among horses at Monufia province (apparent prevalence rate 64% and true prevalence rate 28%) and posed risk for the health of other equines in the region. Results of risk factors identification showed that horses > 5 years of age were at significant risk of getting EHV-1 infection than < 1-year-old horses (OR: 5; P<0.02), while males were twice more prone than females of getting the EHV-1 infection (OR: 2 and P<0.03). There was a significant effect of different localities on the prevalence of EHV-1 infection. The obtained results could be extrapolated to the different districts and governorates of Egypt because of the similarity of the husbandry system of equines all over Egypt.

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A combined vaccine of Equine influenza (EI), equine herpesvirus-1 (EHV-1), rabies virus and tetanus toxoid adjuvanted with saponin and Alhydrogel was prepared. Quality control testing of such vaccine revealed that it was free from foreign contaminants, safe for Guinea-pigs, mice and mares. It was inoculated into Guinea -pigs as a preliminary evaluation for its potency and it was proven safe and potent. Also, it exceeded the permissible protective level allowed to be used for the vaccination of horses. Two groups of mares were used for evaluating the potency of the vaccine. The first one received two doses (5 ml) of the prepared vaccine with 4 weeks interval while the 2 nd group was kept without vaccination as control. The mean haemagglutination inhibition (HI) influenza antibody titer reached its maximum at the 2 nd month post-vaccination (MPV); 2048 while EHV-1 antibodies reached the peak at the 3 rd MPV as recorded by ELISA and neutralizing indices; 1790 and 3.50. Rabies antibodies were detectable in vaccinated mares by the 2 nd week post-vaccination showing titers of 16 and 1.0 by serum neutralization test (SNT) and ELISA, respectively recording their peaks (128 by SNT and 2.15 by ELISA) at the 2 nd MPV. Tetanus antitoxic titer increased till reaching the peak at the 2 nd MPV (40IU/ml) as determined by toxin neutralization test. Depending on these results, it could be concluded that the prepared inactivated EI, EHV-1, rabies and tetanus vaccine is safe and potent for mares providing them with good protective levels of specific antibodies against the 4 used antigens up to 6 months.

Equine herpesvirus-1 is a highly prevalent and frequently pathogenic infection of equines. The most serious clinical signs of disease ranging in severity, from mild respiratory distress to abortion in pregnant mares, neonatal foal death and neuropathogenic disorders. Inactivated EHV-1 adjuvanted vaccines consider the best way for controlling infectious disease. In this research, the prepared EHV-1 adjuvanted vaccines was completely inactivated by binary ethyleneimine (BEI) with (0.008M) and proved to be, sterile, pure, safe and potent when inoculated on VERO cells, mice and horses. Challenge was applied only in inoculated mice to detect the role of all prepared vaccines in the reduction of virus clearance and excretion. There was no any undesirable post vaccinal reaction in horses vaccinated with the prepared vaccine reconistitued in saponin, DEAE-Dextran (100mg/dose) and adjuvanted with Montanide MT Gel-01. The immunogenicity of vaccinated mares adjuvented with different three types of vaccine was assayed by different serological tests revealed that maximum antibodies titre was achieved at 3-4 months' post vaccination and EHV-1 inactivated vaccine reconstituted in DEAE-Dextran (100 mg/dose) is the best one of them followed by the vaccine reconstituted in saponin and vaccine adjuvanted with Montanide MT Gel-01.

An inactivated Equine herpes virus-1 vaccine was successfully improved using carbomer as adjuvant inducing high and long immunity in vaccinated mares in comparison with the convention one adjuvanted with Al-hydra gel and saponin. Such purpose was established by using 0.5% carbomer as adjuvant to the inactivated EHV-1. The applied quality control tests carried out on such vaccine revealed that it is free from foreign contaminants, safe in pregnant mares and mice and potent induced high levels of specific EHV-1 antibodies in vaccinated Guinea pigs and mares as measure by ELISA and SNT. This immunity was sufficient to protect vaccinated horses up to 28 weeks (7months) post-vaccination.