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Hoornweg TE, Schaftenaar W, Rutten VPMG, de Haan CAM. Low gH/gL (Sub)Species-Specific Antibody Levels Indicate Elephants at Risk of Fatal Elephant Endotheliotropic Herpesvirus Hemorrhagic Disease. Viruses 2024; 16:268. [PMID: 38400043 PMCID: PMC10892434 DOI: 10.3390/v16020268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 02/02/2024] [Accepted: 02/03/2024] [Indexed: 02/25/2024] Open
Abstract
Elephant endotheliotropic herpesviruses (EEHVs), of which eleven (sub)species are currently distinguished, infect either Asian (Elephas maximus) or African elephants (Loxodonta species). While all adult elephants are latently infected with at least one EEHV (sub)species, young elephants, specifically those with low to non-detectable EEHV-specific antibody levels, may develop fatal hemorrhagic disease (EEHV-HD) upon infection. However, animals with high antibody levels against EEHV(1A) gB, an immunodominant antigen recognized by antibodies elicited against multiple (sub)species, may also occasionally succumb to EEHV-HD. To better define which animals are at risk of EEHV-HD, gB and gH/gL ELISAs were developed for each of the Asian elephant EEHV subspecies and assessed using 396 sera from 164 Asian elephants from European zoos. Antibody levels measured against gB of different (sub)species correlated strongly with one another, suggesting high cross-reactivity. Antibody levels against gH/gL of different subspecies were far less correlated and allowed differentiation between these (sub)species. Importantly, while high gB-specific antibody levels were detected in the sera of several EEHV-HD fatalities, all fatalities (n = 23) had low antibody levels against gH/gL of the subspecies causing disease. Overall, our data indicate that (sub)species-specific gH/gL ELISAs can be used to identify animals at risk of EEHV-HD when infected with a particular EEHV (sub)species.
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Affiliation(s)
- Tabitha E. Hoornweg
- Section of Virology, Division Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Department of Biomolecular Health Sciences, Utrecht University, 3584 CL Utrecht, The Netherlands
- Section of Immunology, Division Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Department of Biomolecular Health Sciences, Utrecht University, 3584 CL Utrecht, The Netherlands;
| | | | - Victor P. M. G. Rutten
- Section of Immunology, Division Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Department of Biomolecular Health Sciences, Utrecht University, 3584 CL Utrecht, The Netherlands;
- Faculty of Veterinary Science, Department of Veterinary Tropical Diseases, University of Pretoria, Onderstepoort 0110, South Africa
| | - Cornelis A. M. de Haan
- Section of Virology, Division Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Department of Biomolecular Health Sciences, Utrecht University, 3584 CL Utrecht, The Netherlands
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Sree Lakshmi P, Karikalan M, Sharma GK, Sharma K, Chandra Mohan S, Rajesh Kumar K, Miachieo K, Kumar A, Gupta MK, Verma RK, Sahoo N, Saikumar G, Pawde AM. Pathological and molecular studies on elephant endotheliotropic herpesvirus haemorrhagic disease among captive and free-range Asian elephants in India. Microb Pathog 2023; 175:105972. [PMID: 36621697 DOI: 10.1016/j.micpath.2023.105972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/19/2022] [Accepted: 01/03/2023] [Indexed: 01/07/2023]
Abstract
In the present research pathology and molecular diagnosis of elephant endotheliotropic herpes virus-haemorrhagic disease (EEHV-HD) among Asian elephants was studied. Out of 76 cases, 20 were positive for EEHV infection in PANPOL and POL1 based semi-nested PCR. Out of 20 samples, 10 samples were fatal cases of EEHV-HD while 10 were of either subclinical or latent infection. Acute onset haemorrhagic disease with EEHV-HD had anorexia, facial and neck swelling, cyanotic buccal mucosa and tongue, nasal and ocular discharge, and colic. The hallmark of gross finding in all cases were severe haemorrhagic lesions in the internal organs viz. cyanosis of tongue with multifocal petechial haemorrhages, diffuse epicardial and endocardial haemorrhages, swollen liver (rounded edges) with parenchymal haemorrhages, serosal and mucosal haemorrhages in gastrointestinal tract, congested kidneys with corticomedullary haemorrhages, highly congested meninges, and brain capillaries with haemorrhages. Microscopic findings in all the cases had severe vascular changes in the visceral organs. Microthrombi was present in the vasculature of tongue, heart, lung, liver, kidney, and brain. The endothelial lining of most of the blood vessels were swollen with apoptotic changes. Amphophilic to basophilic intranuclear inclusion bodies were observed in the endothelial cells. Immunostaining using anti-EEHV DNAPOL hyperimmune sera revealed intense positive signals in the endothelium of blood vessels and their walls. Quantification of viral load in necropsy tissue samples revealed highest in the heart (7.4 × 106/μg of sample) and least in the brain (9 × 103/μg of sample). The PCR amplicons from EEHV1 specific genes (POL1(U38) and TER were subjected to partial genome sequencing which had 99.9% similarity with the EEHV1A subtype. It was concluded that Asian elephants in India are latently infected for EEHV1 and in all the fatal EEHV-HD cases, EEHV1A subtype was the causative agent with characteristic pathomorphological changes in visceral organs.
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Affiliation(s)
- P Sree Lakshmi
- ICAR- Indian Veterinary Research Institute, Izatnagar, Bareilly, 243122, Uttar Pradesh, India
| | - M Karikalan
- ICAR- Indian Veterinary Research Institute, Izatnagar, Bareilly, 243122, Uttar Pradesh, India.
| | - Gaurav K Sharma
- ICAR- Indian Veterinary Research Institute, Izatnagar, Bareilly, 243122, Uttar Pradesh, India
| | - Kirtika Sharma
- ICAR- Indian Veterinary Research Institute, Izatnagar, Bareilly, 243122, Uttar Pradesh, India
| | - S Chandra Mohan
- ICAR- Indian Veterinary Research Institute, Izatnagar, Bareilly, 243122, Uttar Pradesh, India
| | - K Rajesh Kumar
- Veterinary Officer, Mudumalai Tiger Reserve, The Nigiris, Tamil Nadu, India
| | - Kenei Miachieo
- Sarguja Elephant Reserve, Ambikapur, Chhattisgarh, India
| | - Ajay Kumar
- Bhagwan Birsa Biological Park, Ranchi, Jharkhand, India
| | - M K Gupta
- Faculty of Veterinary Science & Animal Husbandry, Ranchi, Jharkhand, India
| | - Rakesh K Verma
- Sarguja Elephant Reserve, Ambikapur, Chhattisgarh, India
| | - Niranjana Sahoo
- Faculty of Veterinary Science & Animal Husbandry, OUAT, Odisha, India
| | - G Saikumar
- ICAR- Indian Veterinary Research Institute, Izatnagar, Bareilly, 243122, Uttar Pradesh, India
| | - A M Pawde
- ICAR- Indian Veterinary Research Institute, Izatnagar, Bareilly, 243122, Uttar Pradesh, India
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Hoornweg TE, Perera VP, Karunarathne RN, Schaftenaar W, Mahakapuge TA, Kalupahana AW, Rutten VP, de Haan CA. Young elephants in a large herd maintain high levels of elephant endotheliotropic herpesvirus-specific antibodies and do not succumb to fatal haemorrhagic disease. Transbound Emerg Dis 2022; 69:e3379-e3385. [PMID: 35757981 PMCID: PMC9796006 DOI: 10.1111/tbed.14644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 06/23/2022] [Accepted: 06/24/2022] [Indexed: 12/30/2022]
Abstract
Elephant endotheliotropic herpesviruses (EEHVs) have co-existed with elephants for millions of years, yet may cause fatal haemorrhagic disease (EEHV-HD), typically in elephants between 1 and 10 years of age. EEHV is omnipresent in (sub)adult elephants, and young elephants with low EEHV-specific antibody levels are at risk for EEHV-HD, suggesting that fatal disease may occur due to an insufficiently controlled primary infection. To further address this hypothesis, sera of three large elephant cohorts were subjected to a multiple EEHV species ELISA: (I) 96 Asian elephants between 0 and 57 years, including 13 EEHV-HD fatalities, from European zoo herds typically sized five to six elephants, (II) a herd of 64 orphaned elephants aged 0-15 years at the Elephant Transit Home in Sri Lanka and (III) 31 elephants aged 8-63 years, part of a large herd of 93 elephants at Pinnawala Elephant Orphanage, Sri Lanka. All Sri Lankan elephants showed high EEHV-specific antibody levels regardless of their age. While antibody levels of most European zoo elephants were comparable to those of Sri Lankan elephants, the average antibody level of the European juveniles (1-5 years of age) was significantly lower than those of age-matched Sri Lankan individuals. Moreover, the European juveniles showed a gradual decrease between 1 and 4 years of age, to be attributed to waning maternal antibodies. Maintenance of high levels of antibodies in spite of waning maternal antibodies in young Sri Lankan elephants is likely due to the larger herd size that increases the likelihood of contact with EEHV-shedding elephants. Together with the observation that low levels of EEHV-specific antibodies correlate with increased numbers of EEHV-HD fatalities, these results suggest that infection in presence of high maternal antibody levels may protect calves from developing EEHV-HD, while at the same time activating an immune response protective in future encounters with this virus.
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Affiliation(s)
- Tabitha E. Hoornweg
- Section of VirologyDivision Infectious Diseases and ImmunologyFaculty of Veterinary MedicineDepartment of Biomolecular Health SciencesUtrecht UniversityUtrechtThe Netherlands,Section of ImmunologyDivision Infectious Diseases and ImmunologyFaculty of Veterinary MedicineDepartment of Biomolecular Health SciencesUtrecht UniversityUtrechtThe Netherlands
| | - Vijitha P. Perera
- Department of Wildlife Conservation, Elephant Transit HomeUdawalaweSri Lanka
| | | | - Willem Schaftenaar
- Veterinary Advisor EAZA Elephant TAGRotterdam ZooRotterdamThe Netherlands
| | - Thilini A.N. Mahakapuge
- Faculty of Veterinary Medicine and Animal ScienceDepartment of Veterinary PathobiologyUniversity of PeradeniyaPeradeniyaSri Lanka
| | - Anil. W. Kalupahana
- Faculty of Veterinary Medicine and Animal ScienceDepartment of Veterinary PathobiologyUniversity of PeradeniyaPeradeniyaSri Lanka
| | - Victor P.M.G. Rutten
- Section of ImmunologyDivision Infectious Diseases and ImmunologyFaculty of Veterinary MedicineDepartment of Biomolecular Health SciencesUtrecht UniversityUtrechtThe Netherlands,Faculty of Veterinary ScienceDepartment of Veterinary Tropical DiseasesUniversity of PretoriaOnderstepoortSouth Africa
| | - Cornelis A.M. de Haan
- Section of VirologyDivision Infectious Diseases and ImmunologyFaculty of Veterinary MedicineDepartment of Biomolecular Health SciencesUtrecht UniversityUtrechtThe Netherlands
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Yang N, Bao M, Zhu B, Shen Q, Guo X, Li W, Tang R, Zhu D, Tang Y, Phalen DN, Zhang L. Elephant Endotheliotropic Herpesvirus 1, 4 and 5 in China: Occurrence in Multiple Sample Types and Implications for Wild and Captive Population Surveillance. Viruses 2022; 14:v14020411. [PMID: 35216004 PMCID: PMC8875873 DOI: 10.3390/v14020411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 02/13/2022] [Accepted: 02/15/2022] [Indexed: 02/05/2023] Open
Abstract
Elephant endotheliotropic herpesviruses (EEHVs) are important causes of death in both captive and wild Asian elephants (Elephas maximus). Nothing is known about the prevalence of EEHVs in wild or domestic elephants in China. To determine if EEHVs are present in elephants in China, 126 wild elephants from three populations and 202 captive individuals from zoos (n = 155) and the Wild Elephant Valley (n = 47) were screened using semi-nested polymerase chain reaction assays with EEHV-redundant and EEHV1/4/5-specific primers. EEHV1B and EEHV4 were detected in samples from both wild (EEHV1B:8/126; EEHV4:2/126) and captive (EEHV1B:5/155; EEHV4:9/155) elephants, while EEHV1A (six cases) and EEHV5 (one case) were only present in the captive elephants from the Wild Elephant Valley. EEHV1 was detected in blood and trunk and oral swabs; EEHV4 was detected in trunk and oral swabs as well as feces; EEHV5 was found in trunk and oral swabs. No significant age or sex association with EEHV1A, EEHV1B, or EEHV5 positivity was observed. An age association with EEHV4 positivity was found, with all unweaned elephants being EEHV4 positive, but an association with the sex of the elephant was not observed. These findings represent the first documentation of EEHV presence in captive and wild elephants in China. These findings also document EEHV1B and EEHV4 shedding in feces and demonstrate the utility of fecal screening as a tool for investigating EEHV4 infection in wild populations of elephants. It is recommended that EEHV testing be included in surveillance programs for captive and wild elephants in China.
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Affiliation(s)
- Nian Yang
- Key Laboratory for Biodiversity and Ecological Engineering of Ministry of Education, Department of Ecology, College of Life Sciences, Beijing Normal University, Beijing 100875, China; (N.Y.); (B.Z.); (R.T.); (D.Z.); (Y.T.)
| | - Mingwei Bao
- Wild Elephant Valley, Jinghong 666100, China;
| | - Biru Zhu
- Key Laboratory for Biodiversity and Ecological Engineering of Ministry of Education, Department of Ecology, College of Life Sciences, Beijing Normal University, Beijing 100875, China; (N.Y.); (B.Z.); (R.T.); (D.Z.); (Y.T.)
| | - Qingzhong Shen
- Ecotourism Management Institute of Yunnan Xishuangbanna National Nature Reserve, Jinghong 666100, China;
| | - Xianming Guo
- Research Institute of Xishuangbanna National Nature Reserve, Jinghong 666100, China;
| | - Wenwen Li
- Key Laboratory of Coastal Science and Integrated Management, First Institute of Oceanography, Ministry of Natural Resources, Qingdao 266061, China;
| | - Ruchun Tang
- Key Laboratory for Biodiversity and Ecological Engineering of Ministry of Education, Department of Ecology, College of Life Sciences, Beijing Normal University, Beijing 100875, China; (N.Y.); (B.Z.); (R.T.); (D.Z.); (Y.T.)
| | - Di Zhu
- Key Laboratory for Biodiversity and Ecological Engineering of Ministry of Education, Department of Ecology, College of Life Sciences, Beijing Normal University, Beijing 100875, China; (N.Y.); (B.Z.); (R.T.); (D.Z.); (Y.T.)
| | - Yinpu Tang
- Key Laboratory for Biodiversity and Ecological Engineering of Ministry of Education, Department of Ecology, College of Life Sciences, Beijing Normal University, Beijing 100875, China; (N.Y.); (B.Z.); (R.T.); (D.Z.); (Y.T.)
| | - David N. Phalen
- Sydney School of Veterinary Science, Faculty of Science, University of Sydney, Sydney, NSW 2006, Australia
- Schubot Exotic Bird Health Center, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, 701 Farm to Market 2818 Service Road, College Station, TX 77840, USA
- Correspondence: (D.N.P.); (L.Z.)
| | - Li Zhang
- Key Laboratory for Biodiversity and Ecological Engineering of Ministry of Education, Department of Ecology, College of Life Sciences, Beijing Normal University, Beijing 100875, China; (N.Y.); (B.Z.); (R.T.); (D.Z.); (Y.T.)
- Correspondence: (D.N.P.); (L.Z.)
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ELEPHANT ENDOTHELIOTROPIC HERPESVIRUS HEMORRHAGIC DISEASE OUTBREAK IN AN INDIAN ZOO. J Zoo Wildl Med 2022; 52:1286-1297. [PMID: 34998302 DOI: 10.1638/2020-0156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/03/2021] [Indexed: 11/21/2022] Open
Abstract
Elephant endotheliotropic herpesvirus hemorrhagic disease (EEHV HD) is an acute viral infection of growing Asian elephants (Elephas maximus). Four apparently healthy subadult Asian elephants aged between 6 and 10 yr at Nandankanan Zoological Park (NKZP), India, died of EEHV HD during August-September 2019. All four elephants were rescued from different reserved forests of Odisha state at less than 1 yr of age and hand reared in the NKZP. Elephants exhibited the clinical signs of lethargy, head swelling, fever, loss of appetite, abdominal distension, scant urination and defecation, signs of colic, lameness, trunk discharge, cyanosis/ulceration of tongue, erratic behavior, and recumbence before death. Period of illness varied between 28 and 42 h. Thrombocytopenia was the common significant hematological observation. No significant biochemical alterations were recorded except for higher creatinine concentrations. Analysis of blood samples in RT-PCR assay using two different sets of primers and probes that targeted terminase gene and major DNA-binding protein gene followed by cPCR and sequencing was positive for EEHV-1A in all four animals. Postmortem examination of all four carcasses showed hemorrhages in internal organs, including the hard palate, heart, lungs, stomach, mesenteric lymph nodes, mesentery, colon serosa, spleen, liver, kidney, and meninges. Histopathology showed congestion and/or hemorrhages in heart, lung, brain, kidney, and liver. There was presence of intranuclear inclusion bodies in the sinusoidal epithelial cells. The outbreak of EEHV HD that resulted in the acute death of four juvenile captive Asian elephants within <30 d, the first of its kind documented in India, is increasing the fear of similar outbreaks in the future.
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Lee MH, Nathan SKSS, Benedict L, Nagalingam P, Latimer E, Hughes T, Ramirez D, Sukor JRA. The first reported cases of elephant endotheliotropic herpesvirus infectious haemorrhagic disease in Malaysia: case report. Virol J 2021; 18:231. [PMID: 34819101 PMCID: PMC8611640 DOI: 10.1186/s12985-021-01694-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 11/05/2021] [Indexed: 12/03/2022] Open
Abstract
Background Elephant endotheliotropic herpesvirus haemorrhagic disease (EEHV HD) is the leading cause of death in captive Asian elephant calves in Asia, North America, and Europe with a mortality rate of ~ 65% in calves that are under human care. Although EEHV HD was first found in elephant camps, more recently it was identified in wild populations which poses a greater threat to the elephant population. Deaths due to EEHV HD have been seen in wild elephants, but the in-situ prevalence and mortality rate is unknown. We report the first EEHV HD cases in Malaysia from 3 wild born endangered Bornean elephant calves from Sabah with known typical clinical signs. Case presentation The first calf died within 24 h of the onset of clinical signs; the second calf died within 12 h of the onset of clinical signs. The third calf succumbed within 72 h. Necropsies revealed that all 3 calves had similar presentations of EEHV HD but in the third calf with less severity. We conducted conventional polymerase chain reaction (cPCR) assays and found EEHV DNA at all 7 loci in the 3 calves; it was identified as EEHV1A, the virus type that has been found in most other reported cases. Conclusion Typical EEHV HD clinical signs and the molecular confirmation of EEHV by cPCR and sequencing point to EEHV as the cause of death. Further genetic investigation of the strain is in progress.
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Affiliation(s)
- Mei-Ho Lee
- Conservation Medicine, 47000, Sungai Buloh, Selangor, Malaysia. .,EcoHealth Alliance, New York, NY, 10018, USA.
| | - Senthilvel K S S Nathan
- Sabah Wildlife Department, 88100, Kota Kinabalu, Sabah, Malaysia.,Wildlife Rescue Unit, Sabah Wildlife Department, 88100, Kota Kinabalu, Sabah, Malaysia
| | - Laura Benedict
- Wildlife Rescue Unit, Sabah Wildlife Department, 88100, Kota Kinabalu, Sabah, Malaysia
| | - Pakeeyaraj Nagalingam
- Wildlife Rescue Unit, Sabah Wildlife Department, 88100, Kota Kinabalu, Sabah, Malaysia
| | - Erin Latimer
- National Elephant Herpesvirus Laboratory, Wildlife Health Sciences Department, Smithsonian's National Zoo, Washington, DC, 20008, USA
| | - Tom Hughes
- Conservation Medicine, 47000, Sungai Buloh, Selangor, Malaysia.,EcoHealth Alliance, New York, NY, 10018, USA
| | - Diana Ramirez
- Wildlife Rescue Unit, Sabah Wildlife Department, 88100, Kota Kinabalu, Sabah, Malaysia
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Patterns of serum immune biomarkers during elephant endotheliotropic herpesvirus viremia in Asian and African elephants. PLoS One 2021; 16:e0252175. [PMID: 34793450 PMCID: PMC8601435 DOI: 10.1371/journal.pone.0252175] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 11/02/2021] [Indexed: 12/23/2022] Open
Abstract
Hemorrhagic disease (HD) caused by a group of elephant endotheliotropic herpesviruses (EEHV) is one of the leading causes of death for young elephants in human care. These viruses are widespread and typically persist latently in adult elephants with no negative effects; however, in juvenile Asian and more recently young African elephants, the onset of disease can be rapid and the mortality rate high. Measuring biomarkers associated with the immune response could be beneficial to understanding underlying disease processes, as well as the management of infection and HD. The goal of this study was to measure acute phase proteins and cytokines in serum collected from elephants infected with EEHV (13 Asian and 1 African) and compare concentrations according to presence, severity and outcome of disease. Serum amyloid A (SAA) and haptoglobin (HP) were higher in elephants with EEHV viremia than those without; concentrations increased with increasing viral load, and were higher in fatal cases compared to those that survived. In Asian elephants, SAA was also higher during EEHV1 viremia compared to EEHV5. Cytokine concentrations were typically low, and no statistical differences existed between groups. However, in individuals with detectable levels, longitudinal profiles indicated changes in tumor necrosis factor alpha (TNF-α) and interleukin-2 (IL-2) that may reflect an immune response to EEHV infection. However, the overall low concentrations detected using previously validated assays do not support the presence of a 'cytokine storm' and suggest more work is needed to understand if sub-optimal immune responses could be involved in disease progression. These results highlight the potential benefit of measuring circulating biomarker concentrations, such as APPs and cytokines, to improve our understanding of EEHV viremia and HD, assist with monitoring the progression of disease and determining the impact of interventions.
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Jesus SA, Doherr MG, Hildebrandt TB. Elephant Endotheliotropic Herpesvirus Impact in the European Asian Elephant ( Elephas maximus) Population: Are Hereditability and Zoo-Associated Factors Linked with Mortality? Animals (Basel) 2021; 11:ani11102816. [PMID: 34679837 PMCID: PMC8532781 DOI: 10.3390/ani11102816] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 09/20/2021] [Accepted: 09/23/2021] [Indexed: 11/16/2022] Open
Abstract
EEHV is a ubiquitous virus, which most likely has co-evolved with elephants and is shed by healthy individuals and maintained in the herds. Yet, the factors determining calf susceptibility to the virus remain unknown. Here, we explored the impact of EEHV-HD in the European captive Asian elephant population in a retrospective statistical study spanning the last 35 years. We show that EEHV-HD was implicated in more than half of all deaths recorded in calves older than one months old. Moreover, the median age across EEHV-HD fatalities was significantly lower compared to other death causes. Finally, we investigated if heredity and zoo-associated factors could be linked to a higher susceptibility of calves to this disease. We used a univariable logistic regression model to evaluate if either fathers, mothers, or zoos could, separately, be considered as risk factors to the development of the disease. Afterwards, we used a two multivariable model, combining: (1) fathers and zoos, and (2) mothers and zoos. Overall, we found that two fathers, one mother, and four zoos had three or more times higher risk of their calves becoming sick when compared to all others, pointing us to the presence of a management or environmental element, which can have paternal and maternal influence and leads to calf susceptibility or resistance to EEHV-HD.
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Affiliation(s)
- Sónia A. Jesus
- Department of Reproduction Management, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Straße 17, 10315 Berlin, Germany;
- Correspondence:
| | - Marcus G. Doherr
- Institute for Veterinary Epidemiology and Biostatistics, Freie Universität, Königsweg 67, 14163 Berlin, Germany;
| | - Thomas B. Hildebrandt
- Department of Reproduction Management, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Straße 17, 10315 Berlin, Germany;
- Faculty of Veterinary Medicine, Freie Universität, Oertzenweg 19 b, 14163 Berlin, Germany
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Yun Y, Sripiboon S, Pringproa K, Chuammitri P, Punyapornwithaya V, Boonprasert K, Tankaew P, Angkawanish T, Namwongprom K, Arjkumpa O, Brown JL, Thitaram C. Clinical characteristics of elephant endotheliotropic herpesvirus (EEHV) cases in Asian elephants ( Elephas maximus) in Thailand during 2006-2019. Vet Q 2021; 41:268-279. [PMID: 34511026 PMCID: PMC8475116 DOI: 10.1080/01652176.2021.1980633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Background Elephant endotheliotropic herpesvirus causes a hemorrhagic disease (EEHV-HD) that is a major cause of death in juvenile Asian elephants with EEHV1 and EEHV4 being the most prevalent. Aim To perform a retrospective clinical data analysis. Methods Records of a total of 103 cases in Thailand confirmed by polymerase chain reaction (PCR) on blood and/or tissue samples. Results The severity of clinical signs varied among EEHV subtypes. EEHV1A was the most prevalent with 58%, followed by EEHV4 with 34%, EEHV1B with 5.8% and EEHV1&4 co-infection with 1.9%. Overall case fatality rate was 66%. When compared among subtypes, 100% case fatality rate was associated with EEHV1&4 co-infection, 83% with EEHV1B, 75% with EEHV1A, and the lowest at 40% for EEHV4. Calves 2- to 4-year old were in the highest age risk group and exhibited more severe clinical signs with the highest mortality. Majority of cases were found in weaned or trained claves and higher number of cases were observed in rainy season. A gender predilection could not be demonstrated. Severely affected elephants presented with thrombocytopenia, depletion of monocytes, lymphocytes and heterophils, a monocyte:heterophil (M:H) ratio lower than 2.37, hypoproteinemia (both albumin and globulin), severe grade of heterophil toxicity, and low red blood cell counts and pack cell volumes. Survival was not affected by antiviral drug treatment in the severely compromised animals. Conclusion Early detection by laboratory testing and aggressive application of therapies comprising of supportive and anti-viral treatment can improve survival outcomes of this disease.
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Affiliation(s)
- Yaoprapa Yun
- Faculty of Veterinary Medicine, Center of Elephant and Wildlife Research, Chiang Mai University (FVM-CMU), Chiang Mai, Thailand.,Graduate Program in Veterinary Science, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Supaphen Sripiboon
- Faculty of Veterinary Medicine, Department of Large Animal and Wildlife Clinical Sciences, Kasetsart University (FVM-KU), Kamphaeng Saen Campus, Nakornpathom, Thailand
| | - Kidsadagon Pringproa
- Faculty of Veterinary Medicine, Department of Veterinary Biosciences and Public Health, Chiang Mai University, Chiang Mai, Thailand
| | - Phongsakorn Chuammitri
- Faculty of Veterinary Medicine, Department of Veterinary Biosciences and Public Health, Chiang Mai University, Chiang Mai, Thailand
| | - Veerasak Punyapornwithaya
- Faculty of Veterinary Medicine, Veterinary Public Health and Food Safety Centre for Asia Pacific, Chiang Mai University, Chiang Mai, Thailand
| | - Khajohnpat Boonprasert
- Faculty of Veterinary Medicine, Center of Elephant and Wildlife Research, Chiang Mai University (FVM-CMU), Chiang Mai, Thailand
| | - Pallop Tankaew
- Faculty of Veterinary Medicine, Center of Elephant and Wildlife Research, Chiang Mai University (FVM-CMU), Chiang Mai, Thailand
| | - Taweepoke Angkawanish
- Elephant Hospital, National Elephant Institute (NEI), Forest Industry Organization, Lampang, Thailand
| | - Kittikul Namwongprom
- Elephant Hospital, National Elephant Institute (NEI), Forest Industry Organization, Lampang, Thailand
| | - Orapun Arjkumpa
- Phra Nakhon Si Ayutthaya Provincial Livestock Office, Phra Nakhon Si Ayutthaya Province, Thailand
| | - Janine L Brown
- Faculty of Veterinary Medicine, Center of Elephant and Wildlife Research, Chiang Mai University (FVM-CMU), Chiang Mai, Thailand.,Center for Species Survival, Smithsonian Conservation Biology Institute (SCBI), Front Royal, VA, USA
| | - Chatchote Thitaram
- Faculty of Veterinary Medicine, Center of Elephant and Wildlife Research, Chiang Mai University (FVM-CMU), Chiang Mai, Thailand.,Department of Companion Animal and Wildlife Clinics, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
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Common SM, Yun Y, Silva-Fletcher A, Thitaram C, Janyamethakul T, Khammesri S, Molenaar FM. Developing a non-invasive method of detecting elephant endotheliotropic herpesvirus infections using faecal samples. Vet Rec 2021; 190:e833. [PMID: 34472109 DOI: 10.1002/vetr.833] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 06/07/2021] [Accepted: 07/27/2021] [Indexed: 02/06/2023]
Abstract
BACKGROUND Elephant endotheliotropic herpesvirus (EEHV)-associated haemorrhagic disease (EEHV-HD) is a leading cause of death in Asian elephant calves across the world. Cases of EEHV-HD have been detected in free-living calves through post-mortem examination (PME) indicating the presence of the virus in the wild. In the absence of a non-invasive sampling method, little research into free-living populations has been possible. This study aimed to provide evidence that faeces can be used as a non-invasive sampling method for the detection of EEHV excretion using quantitative polymerase chain reaction. METHODS Serial saliva swabs and faecal samples were taken from five captive Asian elephants in Thailand over 12 weeks. To ensure the presence of detectable elephant DNA within the sample, qPCR was run for amplification of the Asian elephant tumour necrosis factor (TNF-α) gene, EEHV1 and EEHV4. RESULTS Of 28 sample pairs, seven saliva samples were positive for EEHV, of which two had paired positive faecal samples. CONCLUSIONS This study presents the first evidence that EEHV is excreted in faeces at detectable levels. This method may in future be used for improved understanding of the epidemiology of EEHV in free-living elephant populations, as well as detection of EEHV excretion in captive herds.
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Affiliation(s)
- Sophie M Common
- Institute of Zoology, Zoological Society of London, Regents Park, London, NW8 7LS, UK.,The Royal Veterinary College, Hatfield, Hertfordshire, UK
| | - Yaoprapa Yun
- Center of Elephant and Wildlife Research, Faculty of Veterinary Medicine, Chiang Mai University (FVM-CMU), Chiang Mai, Thailand
| | | | - Chatchote Thitaram
- Center of Elephant and Wildlife Research, Faculty of Veterinary Medicine, Chiang Mai University (FVM-CMU), Chiang Mai, Thailand
| | | | - Siripat Khammesri
- Center of Elephant and Wildlife Research, Faculty of Veterinary Medicine, Chiang Mai University (FVM-CMU), Chiang Mai, Thailand
| | - Fieke M Molenaar
- Whipsnade Zoo, Zoological Society of London, Dunstable, Bedfordshire, UK
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11
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Perrin KL, Kristensen AT, Bertelsen MF, Denk D. Retrospective review of 27 European cases of fatal elephant endotheliotropic herpesvirus-haemorrhagic disease reveals evidence of disseminated intravascular coagulation. Sci Rep 2021; 11:14173. [PMID: 34238966 PMCID: PMC8266883 DOI: 10.1038/s41598-021-93478-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 06/25/2021] [Indexed: 02/06/2023] Open
Abstract
Elephant endotheliotropic herpesvirus haemorrhagic disease (EEHV-HD) is widely acknowledged as the most common cause of mortality in young Asian elephants (Elephas maximus) in captivity. The objective of the current study was to perform a blinded, retrospective pathology review of European EEHV-HD fatalities, constituting the largest systematic assessment of EEHV-HD pathology to date. Findings between viral genotypes were compared with the aim to investigate if disseminated intravascular coagulation (DIC) could be substantiated as a significant complicating factor, thereby increasing the understanding of disease pathophysiology. Immunohistochemical staining confirmed endothelial cell (EC) damage and the presence of EC intranuclear inclusion bodies, demonstrating a direct viral cytopathic effect. Microthrombi were observed in 63% of cases in several organs, including lungs, which, together with widespread haemorrhage and thrombocytopenia reported in EEHV-HD case reports, supports the presence of overt DIC as a serious haemostatic complication of active EEHV infection. Death was attributed to widespread vascular damage with multi-organ dysfunction, including severe acute myocardial haemorrhage and subsequent cardiac failure. Systemic inflammation observed in the absence of bacterial infection may be caused by cytokine release syndrome. Findings reinforce the necessity to investigate cytokine responses and haemostatic status during symptomatic and asymptomatic EEHV viraemia, to potentially support the use of anti-inflammatory treatment in conjunction with anti-viral therapy and cardiovascular support.
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Affiliation(s)
- K L Perrin
- Center for Zoo and Wild Animal Health, Copenhagen Zoo, Roskildevej 38, 2000, Frederiksberg, Denmark.
- The Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Dyrlægevej 16, 1870, Frederiksberg, Denmark.
| | - A T Kristensen
- The Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Dyrlægevej 16, 1870, Frederiksberg, Denmark
| | - M F Bertelsen
- Center for Zoo and Wild Animal Health, Copenhagen Zoo, Roskildevej 38, 2000, Frederiksberg, Denmark
| | - D Denk
- International Zoo Veterinary Group, Station House, Parkwood Street, Keighley, BD21 4NQ, UK
- Institute for Animal Pathology, Ludwig-Maximilians-University, Veterinärstr. 13, 80539, Munich, Germany
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12
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Hoornweg TE, Schaftenaar W, Maurer G, van den Doel PB, Molenaar FM, Chamouard-Galante A, Vercammen F, Rutten VPMG, de Haan CAM. Elephant Endotheliotropic Herpesvirus Is Omnipresent in Elephants in European Zoos and an Asian Elephant Range Country. Viruses 2021; 13:v13020283. [PMID: 33670367 PMCID: PMC7917619 DOI: 10.3390/v13020283] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/05/2021] [Accepted: 02/06/2021] [Indexed: 11/16/2022] Open
Abstract
Elephant endotheliotropic herpesviruses (EEHVs) may cause acute, often lethal, hemorrhagic disease (EEHV-HD) in young elephants. Prevalence of EEHV in different elephant populations is still largely unknown. In order to improve diagnostic tools for the detection of EEHV infections and to obtain insight into its spread among elephants, we developed novel ELISAs based on EEHV1A gB and gH/gL. Performance of the ELISAs was assessed using sera from 41 European zoo elephants and 69 semi-captive elephants from Laos, one of the Asian elephant range countries. Sera from all (sub)adult animals tested (≥5 years of age) showed high reactivity with both gB and gH/gL, indicating that EEHV prevalence has been highly underestimated so far. Reactivity towards the antigens was generally lower for sera of juvenile animals (1 > 5 years). Only one (juvenile) animal, which was sampled directly after succumbing to EEHV-HD, was found to be seronegative for EEHV. The two other EEHV-HD cases tested showed low antibody levels, suggesting that all three cases died upon a primary EEHV infection. In conclusion, our study suggests that essentially all (semi-)captive (sub)adult elephants in European zoos and in Laos carry EEHV, and that young elephants with low antibody levels are at risk of dying from EEHV-HD.
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Affiliation(s)
- Tabitha E Hoornweg
- Section Virology, Division Infectious Diseases and Immunology, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands
- Section Immunology, Division Infectious Diseases and Immunology, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands
| | - Willem Schaftenaar
- Veterinary Advisor EAZA Elephant TAG, Rotterdam Zoo, 3041 JG Rotterdam, The Netherlands
| | - Gilles Maurer
- Center for Functional and Evolutionary Ecology (CEFE), Univ. Montpellier, CNRS, EPHE, IRD, Univ. Paul Valéry Montpellier 3, 34090 Montpellier, France
- Zooparc de Beauval & Beauval Nature, 41110 Saint-Aignan, France
| | | | - Fieke M Molenaar
- Zoological Society of London, ZSL Whipsnade Zoo, Dunstable LU6 2LF, Bedfordshire, UK
| | | | - Francis Vercammen
- Antwerp Zoo Centre for Research and Conservation, Antwerp Zoo Society, 2018 Antwerp, Belgium
| | - Victor P M G Rutten
- Section Immunology, Division Infectious Diseases and Immunology, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - Cornelis A M de Haan
- Section Virology, Division Infectious Diseases and Immunology, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands
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13
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Pearson VR, Bosse JB, Koyuncu OO, Scherer J, Toruno C, Robinson R, Abegglen LM, Schiffman JD, Enquist LW, Rall GF. Identification of African Elephant Polyomavirus in wild elephants and the creation of a vector expressing its viral tumor antigens to transform elephant primary cells. PLoS One 2021; 16:e0244334. [PMID: 33544724 PMCID: PMC7864673 DOI: 10.1371/journal.pone.0244334] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 12/07/2020] [Indexed: 11/29/2022] Open
Abstract
Wild elephant populations are declining rapidly due to rampant killing for ivory and body parts, range fragmentation, and human-elephant conflict. Wild and captive elephants are further impacted by viruses, including highly pathogenic elephant endotheliotropic herpesviruses. Moreover, while the rich genetic diversity of the ancient elephant lineage is disappearing, elephants, with their low incidence of cancer, have emerged as a surprising resource in human cancer research for understanding the intrinsic cellular response to DNA damage. However, studies on cellular resistance to transformation and herpesvirus reproduction have been severely limited, in part due to the lack of established elephant cell lines to enable in vitro experiments. This report describes creation of a recombinant plasmid, pAelPyV-1-Tag, derived from a wild isolate of African Elephant Polyomavirus (AelPyV-1), that can be used to create immortalized lines of elephant cells. This isolate was extracted from a trunk nodule biopsy isolated from a wild African elephant, Loxodonta africana, in Botswana. The AelPyV-1 genome contains open-reading frames encoding the canonical large (LTag) and small (STag) tumor antigens. We cloned the entire early region spanning the LTag and overlapping STag genes from this isolate into a high-copy vector to construct a recombinant plasmid, pAelPyV-1-Tag, which effectively transformed primary elephant endothelial cells. We expect that the potential of this reagent to transform elephant primary cells will, at a minimum, facilitate study of elephant-specific herpesviruses.
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Affiliation(s)
- Virginia R. Pearson
- Fox Chase Cancer Center, Program in Blood Cell Development and Function, Philadelphia, Pennsylvania, United States of America
- * E-mail:
| | - Jens B. Bosse
- RESIST Cluster of Excellence, Institute of Virology at Hannover Medical School, Center for Structural Systems Biology, Hamburg, Germany
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Orkide O. Koyuncu
- Princeton University, Department of Molecular Biology, Princeton, New Jersey, United States of America
| | - Julian Scherer
- Princeton University, Department of Molecular Biology, Princeton, New Jersey, United States of America
| | - Cristhian Toruno
- Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah, United States of America
| | - Rosann Robinson
- Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah, United States of America
| | - Lisa M. Abegglen
- Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah, United States of America
| | - Joshua D. Schiffman
- Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah, United States of America
| | - Lynn W. Enquist
- Princeton University, Department of Molecular Biology, Princeton, New Jersey, United States of America
| | - Glenn F. Rall
- Fox Chase Cancer Center, Program in Blood Cell Development and Function, Philadelphia, Pennsylvania, United States of America
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14
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Prompiram P, Wiriyarat W, Bhusri B, Paungpin W, Jairak W, Sripiboon S, Wongtawan T. The occurrence of elephant endotheliotropic herpesvirus infection in wild and captive Asian elephants in Thailand: Investigation based on viral DNA and host antibody. Vet World 2021; 14:545-550. [PMID: 33776322 PMCID: PMC7994120 DOI: 10.14202/vetworld.2021.545-550] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 01/21/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND AND AIM Elephant endotheliotropic herpesvirus (EEHV) is a serious disease, threatening the life of young elephants. Many elephants have been infected with no clinical signs and may serve as carriers spreading this disease. It is important to monitor the disease through clinical signs and molecular diagnosis. In this study we investigated the occurrence of EEHV and the efficiency of different techniques used to monitor EEHV infection in various samples and populations of Asian elephants. MATERIALS AND METHODS Blood and trunk swabs were collected from live elephants, while visceral organs (lung, digestive tract, spleen, lymph nodes, and kidney) were collected from dead elephants. EEHV was detected by polymerase chain reaction (PCR) in whole blood, trunk swabs, and visceral organs as samples, while elephant anti-EEHV immunoglobulin G (IgG) in serum was detected by enzyme-linked immunosorbent assay (ELISA). A total of 162 samples were analyzed in this study: 129 from healthy, 26 from dead, and 7 from sick elephants. RESULTS The present study showed that the overall incidence of EEHV was 40.1% (n=65/162). Approximately 46.2% (n=12/26) and 85.7% (n=6/7) of dead and sick elephants were positive for EEHV by PCR, respectively. All sick elephants that were young and affected by EEHV clinical disease tested negative for the IgG antibody ELISA, suggesting primary EEHV infection in this group. In addition, 2.3% (n=3/129) of subclinical infections were detected using PCR, and trunk swab samples showed slightly higher sensitivity (5.3%, n=2/38) to detect EEHV than whole blood (1.2%, n=1/84). As many as, 48.4% (n=44/91) of healthy elephants were EEHV seropositive (ELISA-positive), suggesting that many elephants in Thailand had previously been infected. Overall, 30% of dead wild elephants had been infected with EEHV (n=3/10). Moreover, statistical analysis revealed no significant differences in the EEHV detection rate between different age groups or sexes (p>0.05). CONCLUSION PCR is better than ELISA to detect EEHV active infection in dead/sick elephants and to monitor EEHV in young elephants. ELISA is suitable for detecting previous EEHV infection and carriers, particularly adults. Theoretically, we could use both PCR and ELISA to increase the sensitivity of testing, along with observing abnormal behavior to efficiently monitor this disease. Identification of EEHV carriers within elephant populations is important to prevent transmission to healthy individuals, especially young elephants with high mortality from EEHV. This is the first report from Thailand regarding EEHV infection in wild elephants, showing the importance of preventing disease transmission between captive and wild elephants.
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Affiliation(s)
- Phirom Prompiram
- The Monitoring and Surveillance Centre for Zoonotic Diseases in Wildlife and Exotic Animals, Faculty of Veterinary Science, Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, 73170, Thailand
- Laboratory of Veterinary Biomedicine, Faculty of Veterinary Science, Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, 73170, Thailand
| | - Witthawat Wiriyarat
- The Monitoring and Surveillance Centre for Zoonotic Diseases in Wildlife and Exotic Animals, Faculty of Veterinary Science, Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, 73170, Thailand
- Department of Preclinical Science, Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, 73170, Thailand
| | - Benjaporn Bhusri
- The Monitoring and Surveillance Centre for Zoonotic Diseases in Wildlife and Exotic Animals, Faculty of Veterinary Science, Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, 73170, Thailand
| | - Weena Paungpin
- The Monitoring and Surveillance Centre for Zoonotic Diseases in Wildlife and Exotic Animals, Faculty of Veterinary Science, Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, 73170, Thailand
| | - Waleemas Jairak
- Zoological Park Organization, 267 Pracharat 1 Road, Bangsue Bangkok 10800, Thailand
| | - Supaphen Sripiboon
- Department of Large Animal and Wildlife Clinical Sciences, Faculty of Veterinary Medicine, Kasetsart University, Kamphaeng Saen Campus, Nakhon Pathom 73140, Thailand
| | - Tuempong Wongtawan
- Laboratory of Veterinary Biomedicine, Faculty of Veterinary Science, Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, 73170, Thailand
- Department of Preclinical Science, Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, 73170, Thailand
- Centre of Excellence for One Health, Akkhraratchakumari Veterinary College, Walailak University, Thai Buri, Tha Sala, Nakhon Si Thammarat 80160 Thailand
- Centre of Excellence Research for Melioidosis and other Microorganism, Walailak University, Thai Buri, Tha Sala, Nakhon Si Thammarat 80160 Thailand
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15
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Serum Health Biomarkers in African and Asian Elephants: Value Ranges and Clinical Values Indicative of the Immune Response. Animals (Basel) 2020; 10:ani10101756. [PMID: 32992555 PMCID: PMC7601509 DOI: 10.3390/ani10101756] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/18/2020] [Accepted: 09/25/2020] [Indexed: 01/07/2023] Open
Abstract
Simple Summary Biomarkers are biological molecules found in the blood or other fluids or tissues that can indicate normal or abnormal processes or disease. Developing tools to measure biomarkers that indicate immune function and establishing concentrations observed within a species is an important first step in their use for managing health and understanding disease processes. Here we report assays, observed value ranges, and concentrations during illness or injury for seven immune biomarkers measured in the serum of African and Asian elephants under human care. Concentrations were variable in both clinical and non-clinical samples, but all seven biomarkers were elevated in at least one case and most increased in response to routine vaccination in a single Asian elephant. These tools provide an exciting avenue for monitoring health status and helping diagnose and treat health problems in wildlife species, like elephants. Abstract Serum biomarkers indicative of inflammation and disease can provide useful information regarding host immune processes, responses to treatment and prognosis. The aims of this study were to assess the use of commercially available anti-equine reagents for the quantification of cytokines (tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ), interleukins (IL) 2, 6, and 10) in African (Loxodonta africana, n = 125) and Asian (Elephas maximus, n = 104) elephants, and alongside previously validated anti-human reagents for acute-phase proteins (serum amyloid A and haptoglobin), calculate species-specific biomarker value ranges. In addition, we used opportunistically collected samples to investigate the concentrations of each biomarker during identified clinical cases of illness or injury, as a first step to understanding what biomarkers may be useful to managing elephant health. Immune biomarkers were each elevated above the calculated species-specific value ranges in at least one clinical case, but due to variability in both clinical and non-clinical samples, only serum amyloid A was significantly higher in clinical compared to non-clinical paired samples, with tendencies for higher TNF-α and IL-10. We also detected increased secretion of serum amyloid A and all five cytokines following routine vaccination of a single Asian elephant, indicating that these biomarkers can be beneficial for studying normal immune processes as well as pathology. This study indicates that assays developed with commercial reagents can be used to quantify health biomarkers in wildlife species and identifies several that warrant further investigation to elucidate immune responses to various pathologies.
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