Efficacy and safety of three different opioid-based immobilisation combinations in blesbok (Damaliscus pygargus phillipsi).

African wildlife species are increasingly being immobilised with combinations of a low dose of potent opioids combined with medetomidine and azaperone. The physiological effects of these combinations in comparison to conventional potent opioidazaperone combinations have scarcely been evaluated. In this cross-over study conducted on eight captive blesbok, we compared the physiological variables of blesbok immobilised with 2 mg of thiafentanil + 10 mg of azaperone (TA); 0.5 mg thiafentanil + 1.5 mg medetomidine (TM), and 0.5 mg thiafentanil + 1.5. mg medetomidine + 10 mg azaperone (TMA). Thiafentanil's effects were antagonised with naltrexone at 10 mg naltrexone per mg thiafentanil, and the medetomidine effects with atipamezole at 5 mg atipamezole per mg medetomidine. The physiological variables were compared between treatment groups using descriptive statistics and repeated measures ANOVA. The TA combination resulted in the shortest induction and recovery times, higher heart rates, respiratory rates, PaO2, SpO2, and lower MAP and A-a gradients, but with less muscle relaxation. The TM and TMA combinations caused marked bradycardia and hypoxaemia. The hypoxaemia was most severe in animals immobilised with TMA, and four of eight blesbok immobilised had a PaO2 < 35 mmHg at the 10- or 15-minute sampling point. These blesbok were provided supplementary oxygen, which corrected the hypoxaemia. The TA combinations caused the lowest degree of physiological compromise. All three combinations were effective for the immobilisation of blesbok, but as the low-dose thiafentanil and high-dose medetomidine combinations caused marked hypoxaemia, supplementary oxygen is recommended when using these combinations.

A comparison of immobilisation quality and cardiorespiratory effects of etorphine-azaperone versus etorphine-midazolam combinations in blesbok.

ABSTRACT: The study compared immobilisation of blesbok (Damaliscus pygargus phillipsi) with etorphine and azaperone vs etorphine and midazolam. Twelve female blesbok, weighing 59.4 ± 2.8 kg, were used. Each animal randomly received Treatment 1 (T1) (etorphine, 0.07 ± 0.003 mg/kg + azaperone, 0.36 ± 0.02 mg/kg) and Treatment 2 (T2) (etorphine, 0.07 ± 0.003 mg/kg + midazolam, 0.20 ± 0.01 mg/kg) with a one-week washout period between treatments. Induction times were recorded followed by physiological monitoring for 45 minutes of immobilisation. Immobilisation was reversed with naltrexone (20 mg per mg etorphine). Recovery times were also recorded. Induction, immobilisation and recovery were scored with subjective measures. Inductions and recoveries did not differ between combinations, but the quality of immobilisation was significantly better with T1. Rectal temperature and blood pressure were significantly lower during T1. Both treatments resulted in severe hypoxaemia and impaired gas exchange, although overall hypoxaemia was more pronounced for T1. Animals treated with T2, however, exhibited a deterioration in respiration as the monitoring period progressed, possibly as a result of impaired ventilatory muscle function due to the effects of midazolam. Both combinations are suitable for adequate immobilisation of blesbok and should be selected based on the specific capture situation. Supplementation with oxygen is highly recommended.

Severe hypoxaemia in field-anaesthetised white rhinoceros (Ceratotherium simum) and effects of using tracheal insufflation of oxygen.

White rhinoceros anaesthetised with etorphine and azaperone combination develop adverse physiological changes including hypoxia, hypercapnia, acidosis, tachycardia and hypertension. These changes are more marked in field-anaesthetised rhinoceros. This study was designed to develop a technique to improve safety for field-anaesthetised white rhinoceros by tracheal intubation and oxygen insufflation. Twenty-five free-ranging white rhinoceros were anaesthetised with an etorphine and azaperone combination for translocation or placing microchips in their horns. Once anaesthetised the rhinoceros were monitored prior to crating for transportation or during microchip placement. Physiological measurements included heart and respiratory rate, blood pressure and arterial blood gas samples. Eighteen rhinoceros were intubated using an equine nasogastric tube passed nasally into the trachea and monitored before and after tracheal insufflation with oxygen. Seven rhinoceros were not intubated or insufflated with oxygen and served as controls. All anaesthetised rhinoceros were initially hypoxaemic (percentage arterial haemoglobin oxygen saturation (%O2Sa) = 49% +/- 16 (mean +/- SD) and PaO2 = 4.666 +/- 1.200 kPa (35 +/- 9 mm Hg)), hypercapnic (PaCO2 = 8.265 +/- 1.600 kPa (62 +/- 12 mm Hg)) and acidaemic (pHa = 7.171 +/- 0.073 ). Base excess was -6.7 +/- 3.9 mmol/l, indicating a mild to moderate metabolic acidosis. The rhinoceros were also hypertensive (systolic blood pressure = 21.861 +/- 5.465 kPa (164 +/- 41 mm Hg)) and tachycardic (HR = 107 +/- 31/min). Following nasal tracheal intubation and insufflation, the %O2Sa and PaO2 increased while blood pHa and PaCO2 remained unchanged. Tracheal intubation via the nose is not difficult, and when oxygen is insufflated, the PaO2 and the %O2Sa increases, markedly improving the safety of anaesthesia, but this technique does not correct the hypercapnoea or acidosis. After regaining their feet following reversal of the anaesthesia, the animals' blood gas values return towards normality.

Immobilisation of impala (Aepyceros melampus) with a ketamine hydrochloride/medetomidine hydrochloride combination, and reversal with atipamezole hydrochloride.

A combination of medetomidine hydrochloride (medetomidine) and ketamine hydrochloride (ketamine) was evaluated in 16 boma-confined and 19 free-ranging impalas (Aepyceros melampus) to develop a non-opiate immobilisation protocol. In free-ranging impala a dose of 220 +/- 34 microg/kg medetomidine and 4.4 +/- 0.7 mg/kg ketamine combined with 7500 IU of hyaluronidase induced recumbency within 4.5 +/- 1.5 min, with good muscle relaxation, a stable heart rate and blood pH. PaCO2 was maintained within acceptable ranges. The animals were hypoxic with reduced oxygen saturation and low PaO2 in the presence of an elevated respiration rate, therefore methods for respiratory support are indicated. The depth of sedation was adequate for minor manipulations but additional anaesthesia is indicated for painful manipulations. Immobilisation was reversed by 467 +/- 108 microg/kg atipamezole hydrochloride (atipamezole) intramuscularly, but re-sedation was observed several hours later, possibly due to a low atipamezole:medetomidine ratio of 2:1. Therefore, this immobilisation and reversal protocol would subject impalas to possible predation or conspecific aggression following reversal if they were released into the wild. If the protocol is used on free-ranging impala, an atipamezole:medetomidine ratio of 5:1 should probably be used to prevent re-sedation.

The epidemiology of tuberculosis in free-ranging African buffalo (Syncerus caffer) in the Kruger National Park, South Africa.

The presence of bovine tuberculosis (Mycobacterium bovis) in the Kruger National Park (KNP) was determined for the first time in 1990. It was diagnosed in an African buffalo (Syncerus caffer) bull, which was found recumbent and in an emaciated and moribund state near the south-western boundary fence. This prompted an investigation into the bovine tuberculosis (BTB) status of the KNP, with emphasis on its epidemiological determinants and risk factors. This report documents the findings of surveys that were conducted from 1990 to 1996. It was found that BTB had entered the KNP ecosystem relatively recently (+/- 1960), and has found favourable circumstances for survival and propagation in a fully susceptible and immunologically naive buffalo population. Indications are that it entered the KNP from across the southern river boundary, where the presence of infected domestic cattle herds had been documented. From there the infection spread through the southern buffalo population and is currently spreading in a northward direction. It was estimated that this northward spread took place at a rate of about 6 km per year; the prospect being that, if this rate of spread is maintained, the entire KNP may be affected in less than 30 years from now. Spillover from buffalo had already occurred in species such as chacma baboon (Papio ursinus), lion (Panthera leo), cheetah (Acinonyx jubatus), kudu (Tragelaphus strepsiceros) and leopard (Panthera pardus). Although there is no indication yet that these species act as maintenance hosts, the possibility is raised that these, or an as yet overlooked species, might assume such a role in future. In the KNP, BTB manifests itself as a chronic and predominantly subclinical disease in buffalo. It may take years for clinical signs to develop, and then only at a terminal stage, when emaciation is a constant feature. It is suspected that the time from infection to death is variable and dependent on the animal's immune response, which can be weakened by such factors as stress, old age or droughts. It was found that, in the interim, buffalo have a normal reproductive life. On necropsy, buffalo show almost exclusively lung and upper respiratory tract involvement, pointing to an aerogenous mode of transmission. Histologically, little sign of encapsulation of lesions was detected, which suggests that they are exceptionally susceptible to BTB and that most lesions are open and infectious and progressive, leading ultimately to death of the individual. Evidence also indicates that BTB is progressive within the herd context (92% being the highest prevalence rate thus far determined in a buffalo herd) as well as progressive within the KNP buffalo population (the implication being that virtually all buffalo herds in the KNP will eventually be infected). Preliminary data suggest a positive correlation between disease prevalence and mortality, with potential mortality reaching up to 10% in buffalo herds having BTB prevalence rates of 50 % and higher. Only the future will tell what the effect of the disease on the population dynamics of buffalo will be.

Use of medetomidine and ketamine for immobilization of free-ranging giraffes.

OBJECTIVE: To develop a dosage correlated with shoulder height (SH) in centimeters for effective immobilization of free-ranging giraffes, using a combination of medetomidine (MED) and ketamine (KET) and reversal with atipamezole (ATP). DESIGN: Prospective study. ANIMALS: 23 free-ranging giraffes. PROCEDURE: The drug combination (MED and KET) was administered by use of a projectile dart. Quality of induction, quality of immobilization, and time to recovery following injection of ATP were evaluated. Physiologic variables measured during immobilization included PaO2, PaCO2, oxygen saturation, end-tidal CO2, blood pH, indirect arterial blood pressure, heart and respiratory rates, and rectal temperature. RESULTS: Sixteen giraffes became recumbent with a dosage (mean +/- SD) of 143 +/- 29 microg of MED and 2.7 +/- 0.6 mg of KET/cm of SH. Initially, giraffes were atactic and progressed to lateral recumbency. Three giraffes required casting with ropes for data collection, with dosages of 166 +/- 5 microg of MED and 3.2 +/- 0.6 mg of KET/cm of SH. Four giraffes required administration of etorphine (n = 2) or were cast with ropes (2) for capture but remained dangerous to personnel once recumbent, precluding data collection. In giraffes successfully immobilized, physiologic monitoring revealed hypoxia and increased respiratory rates. Values for PaCO2, end-tidal CO2, and heart rate remained within reference ranges. All giraffes were hypertensive and had a slight increase in rectal temperature. Atipamezole was administered at 340 +/- 20 microg/cm of SH, resulting in rapid and smooth recoveries. CONCLUSIONS AND CLINICAL RELEVANCE: Medetomidine and KET was an effective immobilizing combination for free-ranging giraffes; however, at the dosages used, it does not induce adequate analgesia for major manipulative procedures. Quality of induction and immobilization were enhanced if the giraffe was calm. Reversal was rapid and complete following injection of ATP.

Serum oxytetracycline concentrations in African elephant (Loxodonta africana) calves after long-acting formulation injection.

Serum oxytetracycline pharmacokinetics were studied in 18 African elephant (Loxodonta africana) calves. Each elephant received separate injections of oxytetracycline at approximately 18 mg/kg i.m. and 8 mg/kg i.v. in a cross-over study. Blood samples were drawn at 0, 24, 48, 72, and 96 hr postinjection. An additional sample was drawn 110 hr before the animals were reinjected in the cross-over study and a final blood sample was drawn 48 hr after the second dose. No lameness or stiffness was observed following i.m. injections. Serum oxytetracycline concentrations >0.5 microg/ml were present 48 hr after initial dosing for all elephants (i.m., i.v., high or low dosage). Only elephants given the high i.m. dosage (18 mg/kg) maintained levels >0.5 microg/ml 72 hr postinjection. No significant difference in serum oxytetracycline concentration with time was observed between the groups given different i.v. dosages. These studies demonstrated that quantifiable serum oxytetracycline concentrations can be maintained in young African elephants with a low-dosage multidose i.m. regimen.

Fundamental cryobiology of selected African mammalian spermatozoa and its role in biodiversity preservation through the development of genome resource banking.

Fundamental cryobiological characteristics of spermatozoa from threatened or endangered species must be determined for successful cryopreservation techniques to be established. In this study, spermatozoa from four diverse species, impala (Aepyceros melampus), wart hog (Phacochoerus aethiopicus), elephant (Loxodonta africana), and lion (Panthera leo), were collected by electroejaculation or epididymal aspiration. Spermatozoal plasma membrane permeability to water (hydraulic conductivity, Lp) and the osmotically inactive fraction of the sperm cell (Vb) were determined from each species. Changes in cell volume were measured over time using an electronic particle counter. A Kedem-Katchalsky membrane transport model was used to theoretically characterize the data to determine Lp and Vb for each species. In addition to determining plasma membrane characteristics, spermatozoa were also studied to determine their sensitivity to low temperatures and to permeating cryoprotectant solutes. Cells maintained at room temperature (20-22 degrees C) were slowly or rapidly exposed to cold temperatures (1-4 degrees C), and percent motility was estimated to determine the sensitivity of the cells to cooling. Spermatozoa were also in media containing 1 M glycerol, dimethyl sulfoxide or ethylene glycol, and percent motility was measured at 15, 30 and 60 min intervals to determine the sensitivity of the cells to the cryoprotectant agent over time. Results indicate that sperm motility is significantly effected by decreased temperatures and the presence of cryoprotectant agents.

The efficacy of an experimental oil-adjuvanted encephalomyocarditis vaccine in elephants, mice and pigs.

An oil-adjuvanted inactivated encephalomyocarditis (EMC) vaccine was developed to protect a wild population of elephants against a natural outbreak of disease. The experimental vaccine was initially tested for efficacy by challenging mice and pigs. Mice showed protection against challenge and pigs developed high antibody levels. Since both vaccinated and control pigs failed to develop clinical disease, apparently due to the low virulence of the strain in this species, protection in pigs could not be evaluated. Vaccinated elephants developed high antibody titers which protected all vaccinates from a challenge roughly two months post-vaccination, whereas controls developed fatal or sub-clinical myocarditis. This is the first report of an inactivated EMC vaccine inducing high antibody titers in domestic and wild animal species. Due to the potency of this vaccine and the acceptability of the oil adjuvant used, it has potential for use in animals in zoological collections as well as in the pig industry.

Ulcerative pododermatitis in free-ranging African elephant (Loxodonta africana) in the Kruger National Park.

The occurrence of severe lameness in adult African elephant bulls in a shrub Mopane (Colophospermum mopane) ecosystem was investigated. Large ulcers in the soles of at least one front foot were seen in each of the recorded cases. Microscopically, the lesion can be described as a severe, chronic-active, ulcerative, bacterial pododermatitis (complicated by hypersensitivity/septic vasculitis). A variety of bacteria were isolated from these lesions as well as from regional lymph nodes. Streptococcus agalactiae was the most consistent isolate, while Dichelobacter nodosus, the only organism known to be involved with foot disease in domestic ruminants, was isolated from two cases. Contributory factors such as body mass, portal of entry and origin of potential pathogens may have predisposed to the development of the lesions.

Respiratory and circulatory parameters of African elephants (Loxodonta africana) anaesthetised with etorphine and azaperone.

Respiratory rate, heart rate, blood-gas tensions (PO2 and PCO2) and pH of arterial (a) and peripheral venous (v) blood, concentration of haemoglobin in arterial blood (Hb), saturation of arterial haemoglobin with oxygen and the end-expiratory concentration of oxygen were measured in 22 juvenile African elephants (Loxodonta africana) anaesthetised with etorphine and azaperone during a period of 35-65 minutes after they had assumed lateral recumbency. Based on these parameters the alveolar-arterial and arterial-peripheral venous differences of PO2 [P(A-a)O2 and P(a-v)O2 respectively] and oxygen content of arterial blood (CaO2) were calculated. Elephants with body mass of < or = 600 kg showed statistically significant changes in the following parameters, compared with elephants with a body mass of more than 600 kg (x +/- SD): PaO2 (64 +/- 11 versus 82 +/- 8 mmHg), P(a-v)O2 (9 +/- 5 versus 22 +/- 9 mmHg), P(A-a)O2(37 +/- 16 versus 15 +/- 8 mmHg) and Hb (148 +/- 20 versus 130 +/- 10 g/l) (p < 0.05). These findings suggested a tendency towards impaired oxygen exchange in the lungs, reduced peripheral extraction of oxygen and elevated oxygen-carrying capacity of arterial blood in smaller elephants. These changes were theoretically attributed to the respiratory-depressant and sympathomimetic effects of higher dosages of etorphine used in the smaller elephants to maintain a clinically acceptable anaesthetic plane. Individual elephants spent 35-150 minutes under anaesthesia and all recovered uneventfully after reversal of etorphine with diprenorphine.

An outbreak of bovine tuberculosis in a free-living African buffalo (Syncerus caffer--sparrman) population in the Kruger National Park: a preliminary report.

Bovine tuberculosis was diagnosed for the first time in an African buffalo (Syncerus caffer) in the Kruger National Park (KNP). The index case was a 2-year-old, emaciated bull which had been found recumbent and obviously ill, near the south-western boundary of the KNP, in July 1990. During a follow-up random sampling of 57 buffalo, from two herds in close proximity to this initial case, nine more suspect cases were found. Mycobacterium bovis was isolated from a lung and thoracic lymph node, respectively, of two of these cases. Histopathologically, all nine of these animals had granulomatous lesions compatible with a diagnosis of mycobacteriosis, but acid-fast organisms could be demonstrated in only one animal.

An outbreak of encephalomyocarditis-virus infection in free-ranging African elephants in the Kruger National Park.

A cluster of four deaths in late December 1993, marked the onset of an outbreak of disease of African elephants (Loxodonta africana) in the Kruger National Park (KNP) in South Africa, which has an estimated population of 7,500 elephants. Mortalities peaked in January 1994, with 32 deaths, and then declined steadily to reach pre-outbreak levels by September, but sporadic losses continued until November. During the outbreak altogether 64 elephants died, of which 53 (83%) were adult bulls. Archival records revealed that, in addition to the usual losses from known causes such as poaching and intraspecific fighting, sporadic deaths from unexplained causes had, in fact, occurred in widely scattered locations from at least 1987 onwards, and from that time until the perceived outbreak of disease there had been 48 such deaths involving 33 (69%) adult bulls. Carcases had frequently become decomposed or had been scavenged by the time they were found, but seven of eight elephants examined early in 1994 had lesions of cardiac failure suggestive of encephalomyocarditis (EMC)-virus infection, and the virus was isolated from the heart muscles of three fresh carcases. The results of tests for neutralizing antibody on 362 elephant sera collected for unrelated purposes from 1984 onwards and kept frozen, indicated that the virus had been present in the KNP since at least 1987. Antibody prevalences of 62 of 116 (53%) 18 of 139 (13%) and seven of 33 (21%) were found in elephants in three different regions of the KNP in 1993 and 1994. Studies had been conducted on myomorph rodents in the KNP for unrelated purposes since 1984, and trapping attempts were increased during the perceived outbreak of disease in elephants. There was a striking temporal correlation between the occurrence of a population explosion (as evidenced by markedly increased catch rates per trap-night) and a surge in prevalence of antibody to EM virus in rodents, and the occurrence of the outbreak of disease in elephants.

[Epidemiologic study of bluetongue in sheep, cattle and different species of wild animals in the Ivory Coast]. / Etude épidémiologique sur la fièvre catarrhale du mouton chez les ovins, les bovins et différentes espèces d'animaux sauvages en Cóte d'Ivoire.

Between 1992 and 1993, a serological survey was conducted in Côte d'Ivoire on 623 sera from sheep, 215 sera from cattle and 211 sera from wild herbivores. These sera were tested for bluetongue virus (BTV) antibodies using an agar gel immunodiffusion test. The purpose of this survey was twofold: to establish the incidence of bluetongue in the country, and to analyse the putative role of BTV in the reproductive pathology of sheep. Seroprevalence was 52 +/- 4% in sheep, 95 +/- 3% in cattle, and 56 +/- 7% in wild herbivores. The authors found antibodies against BTV in kob (Kobus kob Erxleben, 1777), common waterbuck (Kobus ellipsiprymnus Ogilby, 1833), roan antelope (Hippotragus equinus Desmarest, 1804), buffalo (Syncerus caffer Sparrman, 1779), hartebeest (Alcelaphus buselaphus Pallas, 1766) and elephant (Loxodonta africana Blumenbach, 1797). A significant difference was found in seroprevalence in sheep between the three areas covered by the survey. Antibody prevalence increased significantly with age in sheep and wild herbivores, and seroprevalence was higher in dams with a history of abortion. It can therefore be concluded that bluetongue is enzootic in Côte d'Ivoire.

[Prevalence of Trypanosoma infections in different species of wild animals in the Comoé national park on the Ivory Coast: preliminary results of the comparison of 3 diagnostic methods]. / Etude de la prévalence des infections à trypanosomes chez différentes espèces d'animaux sauvages du parc national de la Comoé en Côte d'Ivoire: résultats préliminaires sur la comparaison de trois méthodes de diagnostic.

Compared with the numerous studies of trypanosomosis in domestic animals, few such studies have been carried out on wild animals in West Africa. Preliminary results on the comparison of three detection methods (thin smears, detection of trypanosome antigens by ELISA-Test and Kit for in vitro isolation of trypanosomes, KIVI) in wild animals of Comoe Game Reserve in Côte d'Ivoire confirm the actual presence of trypanosomes; however, no accurate identification of those parasites has been possible, but work is in progress to clarify the taxonomical status of stocks isolated by KIVI.

Ostrich (Struthio camelus) immobilisation using carfentanil and xylazine and reversal with yohimbine and naltrexone.

Ostriches (Struthio camelus) (n = 20) were immobilised from a helicopter by darting with a total dose of 3 mg carfentanil and 150 mg xylazine. An initial excitement phase was displayed, commencing on average at 2.67 min (S.D. 0.72) after darting, and the average time to recumbency was 4.97 min (S.D. 1.05). The average heart and respiration rates prior to reversal were 121.2 (S.D. 19.96) and 13.7 (S.D. 5.96) min-1 respectively. Reversal was achieved by the intravenous injection of yohimbine at approximately 0.125 mg kg-1 and 300 mg of naltrexone, and was uneventful. Further investigations need to be done to establish the most appropriate dosage rates for these preparations in ostriches.