A Serologic and Polymerase Chain Reaction Survey of Equine Herpesvirus in Burchell’s Zebras (Equus quagga), Hartmann’s Mountain Zebras (Equus zebra hartmannae), and Thomson’s Gazelles (Eudorcas thomsonii) in a Mixed Species Savannah Exhibit.

The research investigates the occurrence and potential spread of two types of equine herpesvirus (EHV), specifically EHV-1 and EHV-9, in a mixed animal group that includes Burchell’s zebras, Hartmann’s mountain zebras, and Thomson’s gazelles inhabiting the same savannah exhibit. The study found evidence of potential latent EHV in the zebra population, leading to the implementation of a vaccine protocol, changes in managing pregnant zebra mares, and screening practices for EHV prior to animal transportation.

Informative Overview of the Research

• This study was devised to evaluate the presence and potential interspecies transmission of equine herpesvirus (EHV) 1 and EHV-9 in a group of different species sharing a savannah exhibit. This concern stemmed from existing literature documenting various species affected by these viruses, with zebras believed to be natural hosts of EHV-9.
• The researchers involved in the study carried out serologic (blood serum) and polymerase chain reaction (PCR) surveys, which are methods used to detect and quantify specific genetic material in a sample.

Animal Group and Testing Measures

• The animal group in the study included 18 Burchell’s zebras, 11 Hartmann’s mountain zebras, and 14 Thomson’s gazelles, none of which had been exposed to EHV-1 or EHV-4 vaccination previously.
• The researchers were seeking evidence of the EHV-1 virus by looking for virus neutralization titers (indications of the body’s immunity to a virus) and EHV 1-5 through PCR tests.

Research Findings

• All of the zebras that were tested displayed positive EHV-1 titers, which means they each had antibodies specific to EHV-1 in their blood, suggesting prior infection. These antibodies ranged from a low level of 4 to a high level of 384.
• All zebras and gazelles had negative PCR results for EHV, indicating they did not currently have any of the EHV types 1-5 in their bodies.

Indications and Follow-up Measures

• The positive serology results from the zebras suggest the possibility of a latent equine herpesvirus in these animals. This is akin to how the herpesvirus works in humans, where people can carry the virus for long periods without showing any symptoms.
• As a result, it was recommended to initiate a vaccination protocol for EHV, change how pregnant zebras are taken care of, and to screen for EHV using PCR prior to either sending or receiving animals from the exhibit.