Summary on the 1st European Elephant Endotheliotropic Herpesvirus (EEHV) research workshop

The Elephant Endotheliotropic Herpesvirus (EEHV) is threatening Asian elephant breeding success in Europe and North America, with a total of 27 and 43 confirmed fatal cases, respectively. In the Asian elephant EEP, 60% of calf mortalities are due to EEHV Hemorrhagic Disease (EEHV-HD). This year, two fatalities were already recorded within European zoos.

In order to bring European researchers and clinicians together, on May 20th, the 1st European EEHV Research Workshop was held in Rotterdam, Blijdorp Zoo, organized by Willem Schaftenaar.

The aim was to hear about completed and ongoing research activities and to discuss priorities for action. More than 40 participants from all relevant institutions in Europe working on EEHV as well as veterinarians of affected zoos were present (List of participants). The main topics discussed are summarized below:

Research & Diagnostics

The Elephant Taxon Advisory Group is currently collecting money annually from all elephant holding facilities to provide funds to three selected EEHV research projects performed at Artemis-OneHealth Center, Utrecht (NL), the Animal & Plant Health Agency, Weybridge (UK) and the IZW, Berlin (D). 

The quantitative (q)PCR is the current standard technique used identify viremia and viral load. There are currently two laboratories performing qPCR in Europe:

·       UK: Dr. Akbar Dastjerdi (Akbar.Dastjerdi@apha.gsi.gov.uk) 

·       Germany: Prof. Klaus Osterrieder (no.34@fu-berlin.de).  

All relevant information on EEHV-HD is collated in the updated EAZWV Infectious Disease Fact Sheet (link to new fact sheet to follow shortly).

It is important to collect the right samples ante and post mortem, and for historic cases, to share these samples amongst facilities. Mad Bertelsen from Copenhagen Zoo (Denmark) has offered to establish a -80°C biobank for sample storage for research purposes (contact: mfb@zoo.dk).

Epidemiology/Immunology/Genetics

To date, 11 types of the virus have been identified EEHV 1A, 1B, 2, 3A, 3B, 4, 5A, 5B, 6, 7A und 7B. In Asian elephants, EEHV1 is the main cause of death, followed by EEHV 4 and 5.

Factors, such as familiarly predisposition, antibody transfer and protective function of the mother´s milk, husbandry differences and hereditary coagulopathy are currently under investigation (IZW Berlin). An antibody ELISA has been developed for a first indication on antibody titers in Asian elephants (Erasmus Medical Center, Rotterdam). Construction of glycoproteins (gB, gN and gM) in different expression systems (human cell lines, Leishmania culture) is attempted in the search for the development of a vaccine (Artemis-OneHealth).

Monitoring & Treatment

More effective than treatment of a symptomatic case is the early detection of viraemia by close monitoring of Asian elephant calves at risk (1-8 years old). Training for blood collection and restraint should be given utmost priority and may start as early as 4 months of age. Checking of mucous membranes, activity and sleeping patterns are easy to perform (minor changes in behavior pattern are often the only early symptoms in clinical EEHV cases!). I addition, routine weekly screenings of calves for viraemia and/or virus shedding is strongly recommended. More info: EEHV Monitoring Guidelines.

If you see a clinical case, the new EEHV-Emergency Treatment Guideline is available here: EEHV Emergency Treatment Protocol. First aid consists of fluid therapy and plasma transfusion. Virostatic drugs, such as Famciclorvir, are still of questionable efficacy, especially in later stages as absorption from the intestine appears disturbed by hemorrhage. Intravenous Ganciclovir is the drug of choice. 

This workshop was a first important step for a united research strategy within Europe.  The aim is to create awareness amongst elephant holding facilities to monitor their calves, develop an action plan and to identify the most important areas for research to be supported in the future. 

Full meeting proceedings can be found here

More  information on EEHV is available online here: www.eehvinfo.org. Please ask Erin Latimer (latimere@si.edu) for the password to access the protected area.

Imke Lüders, Willem Schaftenaar

June 2016