Immunostimulation of Asian elephant (Elephas maximus) blood cells by parapoxvirus ovis and CpG motif-containing bacterial plasmid DNA upregulates innate immune gene expression.

The immune system of Asian elephants (Elephas maximus) is poorly studied, compared to that of livestock, rodents or humans. The innate immune response has become a focus of interest in relation to Elephant endotheliotropic herpesviruses (EEHVs). EEHVs cause a fatal hemorrhagic disease (EEHV-HD) and are a significant threat to captive Asian elephant populations worldwide. Similar to other herpesvirus infections, nearly all animals become infected, but only some develop disease. As progression to EEHV-HD is often acute, a robust innate immune response is crucial to control EEHV infections. This is invariably true of the host in the first instance, but it can also potentially be modulated by intervention strategies. Here, two immunostimulant veterinary medicinal products, authorized for use in domestic species, were tested for their ability to induce innate anti-viral immune responses in Asian elephant blood cells. Sequence data were obtained for a range of previously unidentified Asian elephant immune genes, including C-X-C motif chemokine ligand 10 (CXCL10), interferon stimulated gene 15 (ISG15) and myxovirus GTPase 1 (Mx1), and were employed in the design of species-specific qPCR assays. These assays were subsequently used in analyses to determine fold changes in gene expression over a period of 24 hours. This study demonstrates that both immunostimulant medications are capable of inducing significant innate anti-viral immune responses which suggests that both could be beneficial in controlling EEHV infections in Asian elephants.

ASSESSMENT OF A LANCET-AND-SWAB BLOOD SAMPLING TECHNIQUE FOR SURVEILLANCE OF ELEPHANT ENDOTHELIOTROPIC HERPESVIRUS INFECTION.

Lancing a finger elicits minimal pain in humans and is applied routinely to obtain small volumes of blood for clinical diagnostics. A modified lancet bleeding method and several blood sampling matrices were evaluated in this study for the purpose of routine elephant endotheliotropic herpesvirus (EEHV) surveillance in Asian elephants (Elephas maximus). The procedure enabled weekly sampling from elephants as young as 9 mo of age. The blood sampling matrices were evaluated for their sensitivity measuring ß-actin, tumor necrosis factor α, and/or EEHV-1 by quantitative polymerase chain reaction assays. Foam and flocked swabs produced significantly (P < 0.05) lower quantitation cycles, ie, increased analytical sensitivity, than filter papers, Whatman® FTA cards, or conventional cotton-tipped swabs. The two swab types also demonstrated comparable analytical sensitivity to that of a similar volume of EDTA whole blood for the detection of EEHV-1 DNA. This lancet-and-swab technique proved satisfactory for the detection of EEHV-1 viremia in two Asian elephant calves, and in one instance viremia could be detected 5 days prior to the development of clinical signs. Low blood yield from the lancet application may reduce sensitivity and compromise early detection of viremia. Therefore, standard venipuncture remains the recommended blood sampling method, and training for consistent and regular vein access should continue to be the priority for collections holding elephants. However, if appropriate measures are taken to collect an optimum blood volume, this lancet-and-swab technique offers a suitable alternative for EEHV surveillance in situations where venipuncture may not be practical.