Investigation of Three Newly Identified Equine Parvoviruses in Blood and Nasal Fluid Samples of Clinically Healthy Horses and Horses with Acute Onset of Respiratory Disease

Three newly identified equine parvoviruses (equine parvovirus hepatitis (EqPV-H), equine parvovirus CSF (EqPV-CSF) and equine copivirus (Eqcopivirus)) have recently been discovered in horses with respiratory signs. However, the clinical impact of these three equine parvoviruses has yet to be determined. Nasal fluid samples and blood from 667 equids with acute onset of fever and respiratory signs submitted to a diagnostic laboratory were analyzed for the presence of common equine respiratory pathogens (equine influenza virus, equine herpesvirus-1/-4, equine rhinitis A and B virus, S. equi subspecies equi) as well as EqPV-H, EqPV-CSF and Eqcopivirus by qPCR. An additional 87 clinically healthy horses served as controls. One hundred and seventeen sick horses tested qPCR-positive for at least one of the three parvoviruses. Co-infections with common respiratory pathogens and parvoviruses were seen in 39 sick equids. All 87 clinically healthy horses tested qPCR-negative for all tested common respiratory pathogens and 10 healthy horses tested qPCR-positive for one of the equine parvoviruses. When the frequency of detection for EqPV-H, EqPV-CSF and Eqcopivirus of equids with respiratory signs was compared to that of clinically healthy horses, the difference was not statistically significant (p > 0.05), suggesting that the three recently identified equine parvoviruses do not contribute to the clinical picture of equids with respiratory disease.

Genetic Characterization of Equine Herpesvirus 1 from Clinical Cases and Asymptomatic Horses in Serbia and Bosnia and Herzegovina

Equine herpesvirus 1 (EHV-1) causes considerable economic loss to the equine industry and is spread among susceptible animals during the cycles of latency and reactivation, causing rhinopneumonitis, abortion, and neurological disease. Nucleotide polymorphisms within ORF30 and ORF68 sequences of the viral genome are associated with strain neuropathogenicity and geographical origin. A total of 142 tissue and nasal swab samples from apparently healthy unvaccinated horses were examined to ascertain EHV-1 distribution, diversity, and clinical significance considering the results of virus isolation, sequence analysis, and anamnestic data. The ORF30 and ORF68 molecular study of these circulating strains and archival isolates from abortion storms aimed to contribute to the perception of strain pathogenicity and origin. EHV-1 was detected by PCR and virus isolation in 81 and 45.1% of the analyzed samples, respectively, and 82.1% of the representative samples were neuropathogenic strains. The ORF68-based grouping was restricted by the pronounced polymorphism of Balkan EHV-1 strains, and only two isolates were assigned to group 4. The cases of abortion were caused by neuropathogenic strains that also circulate within the horse population with no documented outbreaks of disease. It was evident that strain virulence is not solely accountable for the development of clinical symptoms in affected animals. Neural tissue is significant for virus latency and reactivation, considering the number of EHV-1 isolates from apparently healthy stressed horses. Special care must be taken when accommodating together immunologically naive and latently infected horses since asymptomatic carriers silently shed EHV-1.

Seroprevalence of Equine Herpesvirus 1 (EHV-1) and Equine Herpesvirus 4 (EHV-4) in the Northern Moroccan Horse Populations

This study reports the first equine herpesvirus-1 (EHV-1) and equine herpesvirus-4 (EHV-4) seroprevalence investigation in horse populations of Morocco in 24 years. It also aims to determine antibody titers in horses vaccinated under field conditions with a monovalent EHV-1 vaccine. Blood samples were collected from 405 horses, including 163 unvaccinated and 242 vaccinated animals. They were tested using a commercial type-specific enzyme-linked immunosorbent assay (ELISA) and a virus neutralization test (VNT). Overall, 12.8% unvaccinated, and 21.8% vaccinated horses were positive for EHV-1. All samples were positive for EHV-4 when tested with the type-specific ELISA. In the vaccinated group, the VNT revealed a mean antibody titer of 1:49 for EHV-1 and 1:45 for EHV-4.

A SYSTEMATIC REVIEW AND META-ANALYSIS TO ASSESS THE SIGNIFICANCE OF MICROBIAL INFECTIONS IN ZEBRA

Wild equids can harvest multiple-host infectious agents that are able to affect other wildlife species, but also domestic animals and humans. The contact between wild and domestic equids is constantly increasing due to the depletion of natural areas, climate and land-usage changes, which could result in burdensome epidemics. Nevertheless, currently there is a lack of adequate epidemiological data from zebra. Three electronic databases were searched from 10 to 20 March 2021 for publications reporting bacterial, viral and protozoan infections in zebra. Data for a total of 12 nominal variables were extracted from reviewed papers to undergo a qualitative analysis on microbial infections in zebra. Prevalence-reporting studies were subjected to meta-analysis for estimating the pooled prevalence and seroprevalence of infectious agents in wild zebra populations. We identified 29 pathogen species and the most represented were Equine Herpesvirus 1 and 9, Bacillus anthracis, African Horse Sickness virus and Theileria equi. They were reported from all the three zebra species, both in captivity and wilderness. Pooled seroprevalences were estimated for the equine Orbiviruses AHSV (70%; 95%CI: 35-96%) and EEV (21%; 95%CI: 8-38%) and for the equine α -Herpesviruses EHV-1 (72%; 95%CI: 43-93%), EHV-4 (40%; 95%CI: 0-100%) and EHV-9 (58%; 95%CI: 9-98%), and pooled prevalences for the equine piroplasms T. equi (100%; 95%CI: 94-100%) and B. caballi (8%; 95%CI: 0-28%). Zebra is most probably a reservoir from which AHSV, EHV-1 and T. equi can be transmitted to horse populations, potentially causing disastrous epidemics. Zebra can also harvest zoonotic pathogens like B. anthracis, A. phagocytophylum, CCHFV and T. brucei. Other agents like EHV-9, BPV-1 and BPV-2 have the potential to spread from zebra to other wild endangered animal species. We conclude that zebra is an important host for multiple and dangerous pathogens. Alert and epidemiological research should be increased on infectious agents of zebra.