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PubMed2006

Tuberculosis in elephants: antibody responses to defined antigens of Mycobacterium tuberculosis, potential for early diagnosis, and monitoring of treatment.

Tuberculosis (TB) in elephants is a re-emerging zoonotic disease caused primarily by Mycobacterium tuberculosis. Current diagnosis relies on trunk wash culture, the only officially recognized test, which has serious limitations. Innovative and efficient diagnostic methods are urgently needed. Rapid identification of infected animals is a crucial prerequisite for more effective control of TB, as early diagnosis allows timely initiation of chemotherapy. Serology has diagnostic potential, although key antigens have not been identified and optimal immunoassay formats are not established. To characterize the humoral responses in elephant TB, we tested 143 serum samples collected from 15 elephants over time. These included 48 samples from five culture-confirmed TB cases, of which four were in Asian elephants infected with M. tuberculosis and one was in an African elephant with Mycobacterium bovis. Multiantigen print immunoassay (MAPIA) employing a panel of 12 defined antigens was used to identify serologic correlates of active disease. ESAT-6 was the immunodominant antigen recognized in elephant TB. Serum immunoglobulin G antibodies to ESAT-6 and other proteins were detected up to 3.5 years prior to culture of M. tuberculosis from trunk washes. Antibody levels to certain antigens gradually decreased in response to antitubercular therapy, suggesting the possibility of treatment monitoring. In addition to MAPIA, serum samples were evaluated with a recently developed rapid test (RT) based on lateral flow technology (ElephantTB STAT-PAK). Similarly to MAPIA, infected elephants were identified using the RT up to 4 years prior to positive culture. These findings demonstrate the potential for TB surveillance and treatment monitoring using the RT and MAPIA, respectively.

Animals↗

PubMed2003

Plasma and erythrocyte fatty acids in captive Asian (Elephas maximus) and African (Loxodonta africana) elephants.

The fatty acid components of the plasma triglycerides and the phospholipid fractions of the red blood cells of a captive group of two African (Loxodonta africana) and four Asian (Elephas maximus) elephants were investigated. All the animals received the same diet of hay, fruits and vegetables, and concentrates. A comparison with data from free-ranging African elephants or Asian work-camp elephants showed that the captive elephants had lower proportions of polyunsaturated fatty acids (PUFAs), and for several lipid fractions a higher n-6:n-3 ratio, than their counterparts in the wild or under the more natural, in terms of diet, work-camp conditions. The difference in PUFA content was smaller in the African than in the Asian elephants. The captive Asian elephants tended to have lower levels of n-3 and total unsaturated fatty acids in their red blood cells than the captive African elephants.

Animals↗

PubMed2004

The return of the giants: ecological effects of an increasing elephant population.

Northern Botswana and adjacent areas, have the world's largest population of African elephant (Loxodonta africana). However, a 100 years ago elephants were rare following excessive hunting. Simultaneously, ungulate populations were severely reduced by decease. The ecological effects of the reduction in large herbivores must have been substantial, but are little known. Today, however, ecosystem changes following the increase in elephant numbers cause considerable concern in Botswana. This was the background for the "BONIC" project, investigating the interactions between the increasing elephant population and other ecosystem components and processes. Results confirm that the ecosystem is changing following the increase in elephant and ungulate populations, and, presumably, developing towards a situation resembling that before the reduction of large herbivores. We see no ecological reasons to artificially change elephant numbers. There are, however, economic and social reasons to control elephants, and their range in northern Botswana may have to be artificially restricted.

Animals↗

PubMed1993

1H NMR investigation of the heme cavity of elephant (E7 Gln) met-cyano-myoglobin. Evidence for a B-helix phenylalanine interaction with bound ligand.

A combination of one- and two-dimensional NMR experiments has been used to identify and spatially locate the heme pocket residues in the paramagnetic, low spin, met-cyano complex of elephant myoglobin. In addition to assigning resonances of the conserved residues, we have also assigned Gln64 (E7) and an aromatic ring designated PheA whose side chain is inserted into the heme pocket, as found earlier for elephant carbonmonoxy-myoglobin and oxy-myoglobin (Yu, L. P., La Mar, G. N., and Mizukami, H. (1990) Biochemistry 29, 2578-2585). The assigned conserved proximal side residues (Leu89(F4), Ala90(F5), His93(F8), His97(FG3), Ile99(FG5), Leu104(G5), Phe138(H15), and Tyr146(H23)) and conserved distal side residues (Phe43(CD1), Thr67(E10), Val68(E11), and Ala71(E14)) in elephant met-cyano-myoglobin are found to have orientations similar to those in sperm whale met-cyano-myoglobin. The observed dipolar connectivities and dipolar shift pattern for the substituted Gln64(E7) place the Gln in the heme pocket oriented toward the iron, as found for His64(E7). The conserved structural elements demand that the inserted PheA originate from the B-helix (i.e. Phe27 or Phe33). Dipolar contacts between the inserted PheA and the conserved residues Phe43(CD1), Val68(E11), Ile107(G8), and Gln64(E7), place PheA in the position occupied by the B10 residue in sperm whale myoglobin (Mb), with the larger size of the PheA side chain as compared to the replaced Leu being accommodated by the vacancy that occurs in sperm whale Mb. The paramagnetic induced relaxation places PheA in van der Waals contact with the bound ligand. Hence we conclude that the B10 position of elephant Mb is occupied by a Phe, and this substitution relative to sperm whale Mb is responsible for the low autoxidation rate and low reduction potential of elephant Mb. A reduced autoxidation rate has been reported for a sperm whale synthetic point mutant Leu29(B10) --> Phe (Carver, T. E., Brantley, R. E., Jr., Singleton, E. W., Arduini, R. M., Quillin, M. L., Phillips, G. N., and Olson, J. S. (1992) J. Biol. Chem. 267, 14443-14450). The published sequence of elephant Mb places B-helix Phe residues at position 27(B8) and 33(B14), but a Phe at neither of these positions can account for the observed NMR properties. Since a large proportion of the substitutions in elephant relative to sperm whale Mb, and some of the least conservative, occur in the B-helix, neither a structurally perturbed B-helix nor an error in the sequence can be discounted.

Animals↗

PubMed2006

Extensive deployment of the stented elephant trunk is associated with an increased risk of spinal cord injury.

OBJECTIVE: Thoracic aortic aneurysm repair with the stented elephant trunk technique seems to be associated with an increased risk of spinal cord injury. We investigated whether severe atherosclerosis of the distal landing zone or extensive deployment of the stented elephant trunk is associated with increased risk of spinal cord injury. METHODS: Twenty-five patients underwent thoracic aortic aneurysm repair with the stented elephant trunk technique. The study population included 19 men and had a mean age of 73 +/- 7 years. All patients underwent a median sternotomy with cardiopulmonary bypass and selective cerebral perfusion. The elephant trunk was fixed with a Z-stent distal to the aneurysm during hypothermic circulatory arrest. Thirteen patients underwent concomitant total aortic arch replacement. RESULTS: Six (24%) patients had spinal cord injury. The presence of severe atherosclerosis at the distal landing zone demonstrated a tendency to increase the incidence of spinal cord injury (36% vs 9%, P = .1218). More distal deployment of the stented elephant trunk was significantly associated with increased risk of spinal cord injury (T8.0 +/- 0.6 vs T6.5 +/- 1.1, P = .0043). Univariate logistic regression analysis identified a history of abdominal aortic aneurysm repair (P = .0296) and the vertebral level of the distal landing zone (P = .0249) as significant independent risk factors for spinal cord injury, and only the latter was significant in multivariate analysis (P = .0396). The combination of a distal landing zone of T7 or greater and a history of abdominal aortic aneurysm repair was the strongest predictor for spinal cord injury (71% vs 6%, P = .0047). CONCLUSIONS: Spinal cord injury after stented elephant trunk deployment might be related to occlusion of the excessive intercostal arteries or thromboembolism. Patients with a history of abdominal aortic aneurysm repair who require extensive deployment of the stented elephant trunk seem to be at a higher risk for spinal cord injury.

Aged↗

PubMed1992

Preliminary observations on the training of Burmese elephants using xylazine.

A traditional elephant training method was chosen to be modified by the use of xylazine as a sedative and muscle relaxant. Three elephant calves with different degrees of tameness were trained using xylazine. The drug was helpful in the training process. Xylazine made restraint of the elephants much easier and safer. During training, repeated doses of xylazine were used to prevent beatings, the wounds worsening and to pacify the elephants. The tamest elephant calf was punished less and took less time to be trained than the others. It is important to play with elephant calves to win their acceptance of man. A tame calf still needs training to learn about fettering, walking, sitting, etc. Elephants need to be considered man's working companions, and deserve sympathy and humane treatment.

Journal Article↗

PubMed2004

Liquid storage of Asian elephant (Elephas maximus) sperm at 4 degrees C.

The Asian elephant (Elephas maximus) population in the wild has been in decline for several decades and breeding in captivity has not been self-sustaining. The use of artificial insemination (AI) can help overcome many of the difficulties associated with breeding elephants in captivity; however, the ability to store semen for extended periods of time is critical to the successful application of AI to elephants. The objective of the present study was to assess the effects of four different semen extenders and the presence of egg yolk on the viability and motility of Asian elephant semen stored at 4 degrees C. High quality ejaculates (n=4) were collected from two Asian elephant bulls by rectal massage. Aliquots of each ejaculate were extended in four different diluents (Beltsville thawing solution (BTS); Tris-citric acid (TCA)/fructose-based; Beltsville F5 (BF5); dextrose-supplemented phosphate-buffered saline (PBS)) with or without egg yolk then cooled and stored at 4 degrees C. The percentages of viable (viability) and motile (motility) sperm were evaluated at 8, 24 and 48 h following collection. The addition of egg yolk significantly reduced the percentage loss in viability from initial collection to 48 h compared to extenders without egg yolk (17.0 +/- 8.2 versus 32.6 +/- 8.9 decline in percent viable sperm in the population, respectively; P<0.05). Extender and egg yolk affected (P<0.005) total motility and percent progressively motile sperm at all evaluation times during incubation. TCA + egg yolk maintained higher (P<0.05) levels of progressive motility compared to other extenders supplemented with egg yolk. These results indicate that Asian elephant semen extended in TCA diluent supplemented with egg yolk can maintain at least 50% viability and motility when stored at 4 degrees C for 48 h.

Animals↗

PubMed2004

Evaluation of post-thaw Asian elephant (Elephas maximus) spermatozoa using flow cytometry: the effects of extender and cryoprotectant.

Although the development of semen cryopreservation in the African elephants (Loxodonta africana) has been accomplished, effective procedures for cryopreservation of Asian elephant (Elephas maximus) spermatozoa have not been established. In the present study, we investigate the freezing methods for conservation of Asian elephant spermatozoa under field conditions and identify the most suitable freezing protocols which provide acceptable post-thaw semen quality. Semen was collected from two Asian elephant bulls (EM1 and EM2, 10 ejaculates from each bull) by manual manipulation and were assessed for volume, pH, sperm cell concentration, and progressive motility. Eight out of 20 ejaculates were of acceptable quality (progressive motility >/= 60%), and were used for cryopreservation studies. Semen were frozen in TEST + glycerol, TEST + DMSO, HEPT + glycerol, or HEPT + DMSO. The post-thaw progressive sperm motilities were assessed, and sperm cells were stained with PI and FITC-PNA for membrane and acrosomal integrity assessment using flow cytometry. Post-thaw progressive motility of spermatozoa (EM1: 42.0 +/- 4.3%; EM2: 26.0 +/- 17.3%) and the percentage of membrane and acrosome intact spermatozoa (EM1: 55.5 +/- 8.1%; EM2: 46.3 +/- 6.4%) cryopreserved in TEST + glycerol were significantly higher than (P < 0.05) those frozen in the other medium investigated choices for cryopreservation of Asian elephant spermatozoa. The data support the use of TEST + glycerol as an acceptable cryopreservation media of Asian elephant semen for the establishment of sperm banks.

Acrosome↗

PubMed1998

Chemical signals in the reproduction of Asian (Elephas maximus) and African (Loxodonta africana) elephants.

Asian (Elephas maximus) and African (Loxodonta africana) elephants exhibit polygynous mating that involves female choice of mates and male-male competition for access to females. Chemical signals mediate intersexual and intrasexual interactions associated with reproduction. The need for reliable and honest signals is accentuated by the markedly different social structure of adult males and females. Adult female elephants live in matriarchal herds consisting of a dominant female and several generations of offspring. Adult males are solitary or travel with other males except during breeding periods. Because females have a long 16-week oestrous cycle with a brief 1-week receptive period and a 4-5 year interval between births, a sexually active female is a limited resource. Asian elephant females advertise a forthcoming ovulation by releasing (Z)-7-dodecen-1-yl acetate in their urine during the preovulatory period. African elephants probably produce a sex pheromone as well. Females regularly contact the ano-genital region of other females and show heightened chemosensory responsiveness to urine during the follicular phase. The physiological impacts of this ability to detect reproductive condition (e.g. possible synchronizing or suppressing of oestrus) are uncertain. Males experience an annual period of heightened aggressiveness and highly elevated testosterone concentrations known as musth. Males secrete fluid copiously from their temporal gland and dribble strongly odoriferous urine during musth. Females appear to prefer musth males as mates, and captive Asian females exhibit greater chemosensory responses to urine from males in musth than not. Males in musth are competitively dominant to all other males, even those larger than themselves. Nonmusth males avoid males in musth, and captive Asian bulls show greater interest in musth than nonmusth urine. In captivity subordinate Asian females back away from musth secretions, and females with calves sometimes display protective behaviour. Clearly, chemical signals play an important role in communication by elephants between and within the sexes. Further work is needed to identify more of these chemical messengers and to understand their complete function in mediating reproductive interactions in the elephant social system.

Animals↗

PubMed2004

Cytonuclear genomic dissociation in African elephant species.

African forest and savanna elephants are distinct species separated by a hybrid zone. Because hybridization can affect the systematic and conservation status of populations, we examined gene flow between forest and savanna elephants at 21 African locations. We detected cytonuclear dissociation, indicative of different evolutionary histories for nuclear and mitochondrial genomes. Both paternally (n = 205 males) and biparentally (n = 2,123 X-chromosome segments) inherited gene sequences indicated that there was deep genetic separation between forest and savanna elephants. Yet in some savanna locales distant from present-day forest habitats, many individuals with savanna-specific nuclear genotypes carried maternally transmitted forest elephant mitochondrial DNA. This extreme cytonuclear dissociation implies that there were ancient episodes of hybridization between forest females and savanna males, which are larger and reproductively dominant to forest or hybrid males. Recurrent backcrossing of female hybrids to savanna bulls replaced the forest nuclear genome. The persistence of residual forest elephant mitochondria in savanna elephant herds renders evolutionary interpretations based on mitochondrial DNA alone misleading and preserves a genomic record of ancient habitat changes.

Africa South of the Sahara↗

PubMed2005

Population differentiation within and among Asian elephant (Elephas maximus) populations in southern India.

Southern India, one of the last strongholds of the endangered Asian elephant (Elephas maximus), harbours about one-fifth of the global population. We present here the first population genetic study of free-ranging Asian elephants, examining within- and among-population differentiation by analysing mitochondrial DNA (mtDNA) and nuclear microsatellite DNA differentiation across the Nilgiris-Eastern Ghats, Anamalai, and Periyar elephant reserves of southern India. Low mtDNA diversity and 'normal' microsatellite diversity were observed. Surprisingly, the Nilgiri population, which is the world's single largest Asian elephant population, had only one mtDNA haplotype and lower microsatellite diversity than the two other smaller populations examined. There was almost no mtDNA or microsatellite differentiation among localities within the Nilgiris, an area of about 15,000 km2. This suggests extensive gene flow in the past, which is compatible with the home ranges of several hundred square kilometres of elephants in southern India. Conversely, the Nilgiri population is genetically distinct at both mitochondrial and microsatellite markers from the two more southerly populations, Anamalai and Periyar, which in turn are not genetically differentiated from each other. The more southerly populations are separated from the Nilgiris by only a 40-km-wide stretch across a gap in the Western Ghats mountain range. These results variably indicate the importance of population bottlenecks, social organization, and biogeographic barriers in shaping the distribution of genetic variation among Asian elephant populations in southern India.

Animals↗

PubMed2000

Mitochondrial DNA variation, phylogeography and population structure of the Asian elephant.

We report the first genetic analysis of free-ranging Asian elephants (Elephas maximus). We sampled 118 elephants from Sri Lanka, Bhutan/North India, and Laos/Vietnam by extracting DNA from dung, PCR amplifying and sequencing 630 nucleotides of mitochondrial DNA, including part of the variable left domain of the control region. Comparison with African elephant (Loxodonta africana) sequences indicated a relatively slow molecular clock in the Proboscidea with a sequence divergence of approximately 1%/Myr. Genetic diversity within Asian elephants was low, suggesting a small long-term effective population size. Seventeen haplotypes were identified within Asian elephants, which clustered into two well-differentiated assemblages with an estimated Pliocene divergence of 2.5-3.5 million years ago. The two assemblages showed incomplete geographical partitioning, suggesting allopatric divergence and secondary admixture. On the mainland, little genetic differentiation was observed between elephant populations of Bhutan and India or Laos and Vietnam. A significant difference in haplotype frequencies but relatively weak subdivision was observed between the regions Bhutan-India and Laos-Vietnam. Significant genetic differentiation was observed between the mainland and Sri Lanka, and between northern, mid-latitude and southern regions in Sri Lanka.

Animals↗

PubMed2002

Patterns of molecular genetic variation among African elephant populations.

The highly threatened African elephants have recently been subdivided into two species, Loxodonta africana (savannah or bush elephant) and L. cyclotis (forest elephant) based on morphological and molecular studies. A molecular genetic assessment of 16 microsatellite loci across 20 populations (189 individuals) affirms species level genetic differentiation and provides robust genotypic assessment of species affiliation. Savannah elephant populations show modest levels of phylogeographic subdivision based on composite microsatellite genotype, an indication of recent population isolation and restricted gene flow between locales. The savannah elephants show significantly lower genetic diversity than forest elephants, probably reflecting a founder effect in the recent history of the savannah species.

Africa South of the Sahara↗

PubMed2006

Self-recognition in an Asian elephant.

Considered an indicator of self-awareness, mirror self-recognition (MSR) has long seemed limited to humans and apes. In both phylogeny and human ontogeny, MSR is thought to correlate with higher forms of empathy and altruistic behavior. Apart from humans and apes, dolphins and elephants are also known for such capacities. After the recent discovery of MSR in dolphins (Tursiops truncatus), elephants thus were the next logical candidate species. We exposed three Asian elephants (Elephas maximus) to a large mirror to investigate their responses. Animals that possess MSR typically progress through four stages of behavior when facing a mirror: (i) social responses, (ii) physical inspection (e.g., looking behind the mirror), (iii) repetitive mirror-testing behavior, and (iv) realization of seeing themselves. Visible marks and invisible sham-marks were applied to the elephants' heads to test whether they would pass the litmus "mark test" for MSR in which an individual spontaneously uses a mirror to touch an otherwise imperceptible mark on its own body. Here, we report a successful MSR elephant study and report striking parallels in the progression of responses to mirrors among apes, dolphins, and elephants. These parallels suggest convergent cognitive evolution most likely related to complex sociality and cooperation.

Animals↗

PubMed1999

The developing renal, reproductive, and respiratory systems of the African elephant suggest an aquatic ancestry.

The early embryology of the elephant has never been studied before. We have obtained a rare series of African elephant (Loxodonta africana) embryos and fetuses ranging in weight from 0.04 to 18.5 g, estimated gestational ages 58-166 days (duration of gestation is approximately 660 days). Nephrostomes, a feature of aquatic vertebrates, were found in the mesonephric kidneys at all stages of development whereas they have never been recorded in the mesonephric kidneys of other viviparous mammals. The trunk was well developed even in the earliest fetus. The testes were intra-abdominal, and there was no evidence of a gubernaculum, pampiniform plexus, processus vaginalis, or a scrotum, confirming that the elephant, like the dugong, is one of the few primary testicond mammals. The palaeontological evidence suggests that the elephant's ancestors were aquatic, and recent immunological and molecular evidence shows an extremely close affinity between present-day elephants and the aquatic Sirenia (dugong and manatees). The evidence from our embryological study of the elephant also suggests that it evolved from an aquatic mammal.

Africa↗

PubMed2006

African elephants show high levels of interest in the skulls and ivory of their own species.

An important area of biology involves investigating the origins in animals of traits that are thought of as uniquely human. One way that humans appear unique is in the importance they attach to the dead bodies of other humans, particularly those of their close kin, and the rituals that they have developed for burying them. In contrast, most animals appear to show only limited interest in the carcasses or associated remains of dead individuals of their own species. African elephants (Loxodonta africana) are unusual in that they not only give dramatic reactions to the dead bodies of other elephants, but are also reported to systematically investigate elephant bones and tusks that they encounter, and it has sometimes been suggested that they visit the bones of relatives. Here, we use systematic presentations of object arrays to demonstrate that African elephants show higher levels of interest in elephant skulls and ivory than in natural objects or the skulls of other large terrestrial mammals. However, they do not appear to specifically select the skulls of their own relatives for investigation so that visits to dead relatives probably result from a more general attraction to elephant remains.

Africa↗

PubMed2006

Endotheliotropic elephant herpesvirus, the first betaherpesvirus with a thymidine kinase gene.

Endotheliotropic elephant herpesvirus (elephantid herpesvirus 1; ElHV-1) is apathogenic for African elephants (Loxodonta africana), but causes fatal haemorrhagic disease in Asian elephants (Elephas maximus). This is thought to occur through transmission from African elephants in places where both species are housed, such as zoological gardens. The virus has caused considerable losses in North American and European zoological gardens and thus severely impedes breeding of the endangered Asian elephant. Previously, the ultrastructural and genetic characterization of ElHV-1 from a male Asian elephant that died from the disease at the Berlin zoological gardens in 1998 have been reported. Here, a partial characterization of the ElHV-1 genome is presented. A 60 kbp locus, spanning 34 open reading frames, was analysed. Most of the detected genes were found to be conserved among the herpesviruses and showed an overall arrangement most similar to that of betaherpesviruses, in particular Human herpesvirus 6 and Human herpesvirus 7. Most importantly, in addition to a protein kinase gene that is homologous to the human cytomegalovirus UL97 gene, a thymidine kinase (TK) gene was found, which is generally missing in betaherpesvirus genomes. Thus, ElHV-1 is the only known betaherpesvirus to encode a TK gene. This peculiarity might contribute to the fulminant pathogenicity of ElHV-1, but also provide a crucial enzymic activity for developing an efficient antiviral therapy with currently available nucleoside analogues.

Animal Diseases↗

PubMed2000

Seismic properties of Asian elephant (Elephas maximus) vocalizations and locomotion.

Seismic and acoustic data were recorded simultaneously from Asian elephants (Elephas maximus) during periods of vocalizations and locomotion. Acoustic and seismic signals from rumbles were highly correlated at near and far distances and were in phase near the elephant and were out of phase at an increased distance from the elephant. Data analyses indicated that elephant generated signals associated with rumbles and "foot stomps" propagated at different velocities in the two media, the acoustic signals traveling at 309 m/s and the seismic signals at 248-264 m/s. Both types of signals had predominant frequencies in the range of 20 Hz. Seismic signal amplitudes considerably above background noise were recorded at 40 m from the generating elephants for both the rumble and the stomp. Seismic propagation models suggest that seismic waveforms from vocalizations are potentially detectable by instruments at distances of up to 16 km, and up to 32 km for locomotion generated signals. Thus, if detectable by elephants, these seismic signals could be useful for long distance communication.

Animal Communication↗