Epidemiology of Mycobacterium bovis infection in free-ranging rhinoceros in Kruger National Park, South Africa.

Mycobacterium bovis infection, which is a prominent cause of bovine tuberculosis, has been confirmed by mycobacterial culture in African rhinoceros species in Kruger National Park (KNP), South Africa. In this population-based study of the epidemiology of M. bovis in 437 African rhinoceros (Diceros bicornis, Ceratotherium simum), we report an estimated prevalence of 15.4% (95% CI: 10.4 to 21.0%), based on results from mycobacterial culture and an antigen-specific interferon gamma release assay from animals sampled between 2016 and 2020. A significant spatial cluster of cases was detected near the southwestern park border, although infection was widely distributed. Multivariable logistic regression models, including demographic and spatiotemporal variables, showed a significant, increasing probability of M. bovis infection in white rhinoceros based on increased numbers of African buffalo (Syncerus caffer) herds in the vicinity of the rhinoceros sampling location. Since African buffaloes are important maintenance hosts for M. bovis in KNP, spillover of infection from these hosts to white rhinoceros sharing the environment is suspected. There was also a significantly higher proportion of M. bovis infection in black rhinoceros in the early years of the study (2016­2018) than in 2019 and 2020, which coincided with periods of intense drought, although other temporal factors could be implicated. Species of rhinoceros, age, and sex were not identified as risk factors for M. bovis infection. These study findings provide a foundation for further epidemiological investigation of M. bovis, a multihost pathogen, in a complex ecosystem that includes susceptible species that are threatened and endangered.

Reliability, clinical performance and trending ability of a pulse oximeter and pulse co-oximeter, in monitoring blood oxygenation, at two measurement sites, in immobilised white rhinoceros (Ceratotherium simum).

BACKGROUND: Monitoring blood oxygenation is essential in immobilised rhinoceros, which are susceptible to opioid-induced hypoxaemia. This study assessed the reliability, clinical performance and trending ability of the Nonin PalmSAT 2500 A pulse oximeter's and the Masimo Radical-7 pulse co-oximeter's dual-wavelength technology, with their probes placed at two measurement sites, the inner surface of the third-eyelid and the scarified ear pinna of immobilised white rhinoceroses. Eight white rhinoceros were immobilised with etorphine-based drug combinations and given butorphanol after 12 min, and oxygen after 40 min, of recumbency. The Nonin and Masimo devices, with dual-wavelength probes attached to the third-eyelid and ear recorded arterial peripheral oxygen-haemoglobin saturation (SpO2) at pre-determined time points, concurrently with measurements of arterial oxygen-haemoglobin saturation (SaO2), from drawn blood samples, by a benchtop AVOXimeter 4000 co-oximeter (reference method). Reliability of the Nonin and Masimo devices was evaluated using the Bland-Altman and the area root mean squares (ARMS) methods. Clinical performance of the devices was evaluated for their ability to accurately detect clinical hypoxemia using receiver operating characteristic (ROC) curves and measures of sensitivity, specificity, and positive and negative predictive values. Trending ability of the devices was assessed by calculating concordance rates from four-quadrant plots. RESULTS: Only the Nonin device with transflectance probe attached to the third-eyelid provided reliable SpO2 measurements across the 70 to 100% saturation range (bias - 1%, precision 4%, ARMS 4%). Nonin and Masimo devices with transflectance probes attached to the third-eyelid both had high clinical performance at detecting clinical hypoxaemia [area under the ROC curves (AUC): 0.93 and 0.90, respectively]. However, the Nonin and Masimo devices with transmission probes attached to the ear were unreliable and provided only moderate clinical performance. Both Nonin and Masimo devices, at both measurement sites, had concordance rates lower than the recommended threshold of ≥ 90%, indicating poor trending ability. CONCLUSIONS: The overall assessment of reliability, clinical performance and trending ability indicate that the Nonin device with transflectance probe attached to the third-eyelid is best suited for monitoring of blood oxygenation in immobilised rhinoceros. The immobilisation procedure may have affected cardiovascular function to an extent that it limited the devices' performance.

Natural resistance to worms exacerbates bovine tuberculosis severity independently of worm coinfection.

Pathogen interactions arising during coinfection can exacerbate disease severity, for example when the immune response mounted against one pathogen negatively affects defense of another. It is also possible that host immune responses to a pathogen, shaped by historical evolutionary interactions between host and pathogen, may modify host immune defenses in ways that have repercussions for other pathogens. In this case, negative interactions between two pathogens could emerge even in the absence of concurrent infection. Parasitic worms and tuberculosis (TB) are involved in one of the most geographically extensive of pathogen interactions, and during coinfection worms can exacerbate TB disease outcomes. Here, we show that in a wild mammal natural resistance to worms affects bovine tuberculosis (BTB) severity independently of active worm infection. We found that worm-resistant individuals were more likely to die of BTB than were nonresistant individuals, and their disease progressed more quickly. Anthelmintic treatment moderated, but did not eliminate, the resistance effect, and the effects of resistance and treatment were opposite and additive, with untreated, resistant individuals experiencing the highest mortality. Furthermore, resistance and anthelmintic treatment had nonoverlapping effects on BTB pathology. The effects of resistance manifested in the lungs (the primary site of BTB infection), while the effects of treatment manifested almost entirely in the lymph nodes (the site of disseminated disease), suggesting that resistance and active worm infection affect BTB progression via distinct mechanisms. Our findings reveal that interactions between pathogens can occur as a consequence of processes arising on very different timescales.

Method development to characterise elephant tail hairs by LA-ICP-MS to reflect changes in elemental chemistry.

This paper evaluated analytical methods used to generate time-series data from elephant tail hairs, which can be used to reflect changing exposure to environmental geochemistry. Elephant tail hairs were analysed by three methods sequentially, each providing data to inform subsequent analysis. Scanning Electron Microscopy (SEM) and X-ray Microanalysis visually showed the structure of the hair, specific structures such as tubules, and the mineral crusting around the edge of the hair, informing targeting of subsequent analysis by Laser Ablation-Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). LA-ICP-MS generated time-series data which informed sectioning of the tail hairs for subsequent quantitative analysis for potentially toxic elements and micronutrients using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) of dissolved tail hairs. This novel approach to characterise the tail hair enabled time-series analysis to reflect changes in environmental exposure which may result from seasonal or geochemical spatial variation and could inform elephant movement patterns. The seasonal change between wet and dry seasons was reflected down the length of the hair. Correlations were seen between LA-ICP-MS data and ICP-MS data in several elements including Mg, P, Ca, Fe, Na, Mn and U. This study provided time-series data for the analysis of elephant tail hairs by evaluating analytical challenges to obtaining quantitative data, such as improving protocols to ensure removal of extraneous material, determining where to section the tail hairs to best reflect environmental changes/exposure and ensuring representative analyses. A protocol was established to determine mineral status across a 12-18 month time period utilizing single elephant tail hairs.

Bovine tuberculosis disturbs parasite functional trait composition in African buffalo.

Novel parasites can have wide-ranging impacts, not only on host populations, but also on the resident parasite community. Historically, impacts of novel parasites have been assessed by examining pairwise interactions between parasite species. However, parasite communities are complex networks of interacting species. Here we used multivariate taxonomic and trait-based approaches to determine how parasite community composition changed when African buffalo (Syncerus caffer) acquired an emerging disease, bovine tuberculosis (BTB). Both taxonomic and functional parasite richness increased significantly in animals that acquired BTB than in those that did not. Thus, the presence of BTB seems to catalyze extraordinary shifts in community composition. There were no differences in overall parasite taxonomic composition between infected and uninfected individuals, however. The trait-based analysis revealed an increase in direct-transmitted, quickly replicating parasites following BTB infection. This study demonstrates that trait-based approaches provide insight into parasite community dynamics in the context of emerging infections.

Cardiopulmonary responses of free-ranging African elephant (Loxodonta africana) bulls immobilized with a thiafentanil-azaperone combination.

OBJECTIVE: To determine the time course and certain cardiopulmonary effects of trunk-breathing elephants immobilized with thiafentanil-azaperone. STUDY DESIGN: Prospective descriptive study. ANIMALS: A convenience sample of 10 free-ranging African elephant bulls (estimated weight range: 3000-6000 kg). METHODS: Elephants were immobilized using thiafentanil (15-18 mg) and azaperone (75-90 mg) administered by dart. Once recumbent, the respiratory rate, minute ventilation (V˙e), end-tidal carbon dioxide (Pe'CO2), arterial blood pressure and heart rate were recorded immediately after instrumentation and at 5 minute intervals until 20 minutes. Arterial blood gases were analysed at the time of initial instrumentation and at 20 minutes. On completion of data collection, thiafentanil was antagonized using naltrexone (10 mg mg-1 thiafentanil; administered intravenously). A stopwatch was used to record time to recumbency (dart placement to recumbency) and time to recovery (administration of antagonist to standing). Data were compared using a one-way anova. Data are presented as mean ± standard deviation. RESULTS: All elephants were successfully immobilized, and there were no significant changes in cardiopulmonary variables over the monitoring period. Average time to recumbency was 12.5 (± 3.9) minutes. The measured V˙e was 103 (± 30) L minute-1. The average heart and respiratory rates over the 20 minute immobilization were steady at 49 (± 6) beats minute-1 and 5 (± 1) breaths minute-1, respectively. The mean arterial blood pressure was 153 (± 31) mmHg. The elephants were acidaemic (pH: 7.18 ± 0.06), mildly hypoxaemic (PaO2: 68 ± 15 mmHg; 9.1 ± 2.0 kPa) and hypercapnic (PaCO2: 52 ± 7 mmHg; 6.9 ± 0.9 kPa). Average time to recovery was 2.2 ± 0.5 minutes. CONCLUSION AND CLINICAL RELEVANCE: African elephant bulls can be successfully immobilized using thiafentanil-azaperone. Recumbency was rapid, the cardiopulmonary variables were stable over time, and recovery was rapid and complete. Mild hypoxaemia and hypercapnia were evident.

Reliability of pulse oximetry at four different attachment sites in immobilized white rhinoceros (Ceratotherium simum).

OBJECTIVES: To determine the reliability of peripheral oxygen haemoglobin saturation (SpO2), measured by a Nonin PalmSAT 2500A pulse oximeter with 2000T transflectance probes at four attachment sites (third eyelid, cheek, rectum and tail), by comparing these measurements to arterial oxygen haemoglobin saturation (SaO2), measured by an AVOXimeter 4000 co-oximeter reference method in immobilized white rhinoceros (Ceratotherium simum). STUDY DESIGN: Randomized crossover study. ANIMALS: A convenience sample of eight wild-caught male white rhinoceros. METHODS: White rhinoceros were immobilized with etorphine (0.0026 ± 0.0002 mg kg-1, mean ± standard deviation) intramuscularly, after which the pinna was aseptically prepared for arterial blood sample collection, and four pulse oximeters with transflectance probes were fixed securely to their attachment sites (third eyelid, cheek, rectum and tail). At 30 minutes following recumbency resulting from etorphine administration, the animals were given either butorphanol (0.026 ± 0.0001 mg kg-1) or an equivalent volume of saline intravenously. At 60 minutes following recumbency, insufflated oxygen (15 L minute-1 flow rate) was provided intranasally. In total, the SpO2 paired measurements from the third eyelid (n = 80), cheek (n = 67), rectum (n = 59) and tail (n = 76) were compared with near-simultaneous SaO2 measurements using Bland-Altman to assess bias (accuracy), precision, and the area root mean squares (ARMS) method. RESULTS: Compared with SaO2, SpO2 measurements from the third eyelid were reliable (i.e., accurate and precise) above an SaO2 range of 70% (bias = 1, precision = 3, ARMS = 3). However, SpO2 measurements from the cheek, rectum and tail were unreliable (i.e., inaccurate or imprecise). CONCLUSIONS AND CLINICAL RELEVANCE: A Nonin PalmSAT pulse oximeter with a transflectance probe inserted into the space between the third eyelid and the sclera provided reliable SpO2 measurements when SaO2 was > 70%, in immobilized white rhinoceros.

DEVELOPMENT OF A QUANTITATIVE IMMUNOASSAY FOR SERUM HAPTOGLOBIN AS A PUTATIVE DISEASE MARKER IN THE SOUTHERN WHITE RHINOCEROS (CERATOTHERIUM SIMUM SIMUM).

Objective disease markers in the southern white rhinoceros (Ceratotherium simum simum) are in high demand. In the field, such markers are typically needed to decide whether a captured white rhinoceros is fit to cope with quarantine, transport, or both. Captive white rhinoceros have a need for unbiased biomarkers for early detection of disease. Acute phase proteins, including haptoglobin, are proteins that significantly change their plasma concentration in response to tissue perturbation or inflammation, such as that occurring during infection or neoplastic disease. Acute phase proteins are well known diagnostic tools in both human and veterinary medicine. In this study, an ELISA with commercially available anti-human haptoglobin antibodies for quantification of haptoglobin in white rhinoceros serum was developed. The validity of the haptoglobin assay and haptoglobin as a biomarker of disease was investigated with the use of serum samples from both captive and free-ranging animals with a well-described health status. The assay was precise (intra-assay and interassay reproducibility were 5.0% and 13.1%, respectively) and reliably quantified white rhinoceros haptoglobin serum concentrations consuming low volumes of sample. The assay was sensitive to the presence of free hemoglobin in the sample at levels corresponding to a visibly hemolyzed sample. Haptoglobin was readily measurable, baseline levels (in white rhinoceros with no clinical signs of disease) did not differ between genders, and a significant increase was seen in captive as well as in free-ranging white rhinoceros with inflammatory disease. Thus, haptoglobin is a positive acute phase protein in southern white rhinoceros with potential for use as an objective marker of disease.

Mycobacterium bovis Infection in Free-Ranging African Elephants.

Mycobacterium bovis infection in wildlife species occurs worldwide. However, few cases of M. bovis infection in captive elephants have been reported. We describe 2 incidental cases of bovine tuberculosis in free-ranging African elephants (Loxodonta africana) from a tuberculosis-endemic national park in South Africa and the epidemiologic implications of these infections.

Development of a cytokine gene expression assay for the relative quantification of the African elephant (Loxodonta africana) cell-mediated immune responses.

Immunological assays are the basis for many diagnostic tests for infectious diseases in animals and humans. Application in wildlife species, including the African elephant (Loxodonta africana), is limited however due to lack of information on immune responses. Since many immunoassays require both identified biomarkers of immune activation as well as species-specific reagents, it is crucial to have knowledge of basic immunological responses in the species of interest. Cytokine gene expression assays (GEAs) used to measure specific immune responses in wildlife have frequently shown that targeted biomarkers are often species-specific. Therefore, the aim of this study was to identify elephant-specific cytokine biomarkers to detect immune activation and to develop a GEA, using pokeweed mitogen stimulated whole blood from African elephants. This assay will provide the foundation for the development of future cytokine GEAs that can be used to detect antigen specific immune responses and potentially lead to various diagnostic tests for this species.

Immobilization of African buffaloes (Syncerus caffer) using etorphine-midazolam compared with etorphine-azaperone.

OBJECTIVE: To compare induction times and physiological effects of etorphine-azaperone with etorphine-midazolam immobilization in African buffaloes. STUDY DESIGN: Randomized crossover study. ANIMALS: A group of 10 adult buffalo bulls (mean body weight 353 kg). METHODS: Etorphine-azaperone (treatment EA; 0.015 and 0.15 mg kg-1, respectively) and etorphine-midazolam (treatment EM; 0.015 and 0.15 mg kg-1, respectively) were administered once to buffaloes, 1 week apart. Once in sternal recumbency, buffaloes were instrumented and physiological variables recorded at 5 minute intervals, from 5 minutes to 20 minutes. Naltrexone (20 mg mg-1 etorphine dose) was administered intravenously at 40 minutes. Induction (dart placement to recumbency) and recovery (naltrexone administration to standing) times were recorded. Arterial blood samples were analysed at 5 and 20 minutes. Physiological data were compared between treatments using a general linear mixed model and reported as mean ± standard deviation. Time data were compared using Mann-Whitney U test and reported as median (interquartile range) with p ≤ 0.05. RESULTS: Actual drug doses administered for etorphine, azaperone and midazolam were 0.015 ± 0.001, 0.15 ± 0.01 and 0.16 ± 0.02 mg kg-1, respectively. Induction time for treatment EA was 3.3 (3.6) minutes and not different from 3.2 (3.2) minutes for treatment EM. The overall mean arterial blood pressure was significantly lower for treatment EA (102 ± 25 mmHg) than that for treatment EM (163 ± 18 mmHg) (p < 0.001). The PaO2 for treatment EA (37 ± 12 mmHg; 5.0 ± 1.6 kPa) was not different from that for treatment EM (43 ± 8 mmHg; 5.8 ± 1.1 kPa). Recovery time was 0.8 (0.6) minutes for treatment EA and did not differ from 1.1 (0.6) minutes for treatment EM. CONCLUSIONS AND CLINICAL RELEVANCE: Treatment EA was as effective as treatment EM for immobilization in this study. However, systemic arterial hypertension was a concern with treatment EM, and both combinations produced clinically relevant hypoxaemia. Supplemental oxygen administration is recommended with both drug combinations.

SEROLOGICAL EVIDENCE OF COXIELLA BURNETII INFECTION IN THE WHITE RHINOCEROS (CERATOTHERIUM SIMUM) IN SOUTH AFRICA.

Coxiellosis, or Query (Q) fever, a disease caused by the intracellular bacteria Coxiella burnetii, was recently described in a managed breeding herd of white rhinoceros (Ceratotherium simum) in the southeastern United States. Clinical disease often results in abortion and could represent a conservation challenge for this species. In addition to the reproductive and herd management consequences, coxiellosis is also a zoonotic disease. Infection or clinical disease in any free-ranging rhinoceros species in a national park setting has not been previously described. In this study, evidence of prior infection was measured by immunofluorescent antibody titers in 89 serum samples collected from white rhinoceros within private reserves and a national park in South Africa. Total seropositivity was 48/89 (53.9% [95% CI, 43.6-63.9%]). Animals on private reserves had a seropositivity of 21/51 (41.1% [95% CI, 27.1-55.2%]), and national park rhinoceros had a higher rate of seropositivity at 71.0% [95% CI, 55.9-86.2%] (27/38; P= 0.004). Adults had a higher seropositivity compared with subadults (P= 0.03). There was no difference in seropositivity between sexes (P > 0.05). Results demonstrate that South African white rhinoceros populations are exposed to Coxiella, which could result in underrecognized reproductive consequences. Further studies should investigate potential implications for public health and conservation management of this species.

Shuni Virus in Wildlife and Nonequine Domestic Animals, South Africa.

We screened nonequine animals with unexplained neurologic signs or death in South Africa during 2010-2018 for Shuni virus (SHUV). SHUV was detected in 3.3% of wildlife, 1.1% of domestic, and 2.0% of avian species. Seropositivity was also demonstrated in wildlife. These results suggest a range of possible SHUV hosts in Africa.

The VetMAX™ M. tuberculosis complex PCR kit detects MTBC DNA in antemortem and postmortem samples from white rhinoceros (Ceratotherium simum), African elephants (Loxodonta africana) and African buffaloes (Syncerus caffer).

BACKGROUND: Bovine tuberculosis and tuberculosis are chronic infectious diseases caused by the Mycobacterium tuberculosis complex members, Mycobacterium bovis and Mycobacterium tuberculosis, respectively. Infection with M. bovis and M. tuberculosis have significant implications for wildlife species management, public health, veterinary disease control, and conservation endeavours. RESULTS: Here we describe the first use of the VetMAX™ Mycobacterium tuberculosis complex (MTBC) DNA quantitative real-time polymerase chain reaction (qPCR) detection kit for African wildlife samples. DNA was extracted from tissues harvested from 48 African buffaloes and MTBC DNA was detected (test-positive) in all 26 M. bovis culture-confirmed animals with an additional 12 PCR-positive results in culture-negative buffaloes (originating from an exposed population). Of six MTBC-infected African rhinoceros tested, MTBC DNA was detected in antemortem and postmortem samples from five animals. The PCR was also able to detect MTBC DNA in samples from two African elephants confirmed to have M. bovis and M. tuberculosis infections (one each). Culture-confirmed uninfected rhinoceros and elephants' samples tested negative in the PCR assay. CONCLUSIONS: These results suggest this new detection kit is a sensitive screening test for the detection of MTBC-infected African buffaloes, African elephants and white rhinoceros.

EVALUATION OF A PARTIALLY REVERSIBLE IMMOBILIZATION PROTOCOL USING MEDETOMIDINE, BUTORPHANOL, ZOLAZEPAM-TILETAMINE, AND KETAMINE IN FREE-RANGING WARTHOGS (PHACOCHOERUS AFRICANUS) IN KRUGER NATIONAL PARK, SOUTH AFRICA.

Twenty-one free-ranging warthogs (Phacochoerus africanus) in the Kruger National Park, South Africa, were immobilized with a combination of medetomidine (0.07 ± 0.01 mg/kg), butorphanol (0.26 ± 0.04 mg/kg), tiletamine-zolazepam (0.69 ± 0.15 mg/kg), and ketamine (1.43 ± 0.21 mg/kg) administered intramuscularly by dart. Induction, immobilization, and recovery characteristics were evaluated using a standardized scoring system. In the immobilized warthogs, physiological variables were measured every 5 min and arterial blood gases were analyzed at 15-min intervals. At 45 min after initial drug administration, atipamezole (0.34 ± 0.050 mg/kg) and naltrexone (0.53 ± 0.079 mg/kg) were administered intravenously. Overall, induction quality after darting was scored as excellent and the mean time to safe handling was 5.9 ± 2.0 min. Based on muscle relaxation, and loss of palpebral and pedal reflexes, most subjects (17 out of 21) reached a plane of surgical anesthesia by 10 and 15 min; 20 out of 21 warthogs were in this plane for the duration of the monitoring period. In the immobilized warthogs the overall mean heart rate was 65 ± 15.3 beats per minute, mean respiratory rate was 14.7 ± 5.6 breaths per minute, and the mean rectal temperature was 37.9 ± 1.4°C during the 40 min. Arterial blood gas results showed hypoxemia (mean PaO2 62.1 ± 16.2 mmHg), hypercapnia (mean PaCO2 47.1 ± 5.1 mmHg), and acidemia (mean pH = 7.36 ± 0.04). Values for PaO2 and pH improved over the immobilization period. After antagonist administration, overall recovery quality from immobilization was scored as good, with animals standing at a mean time of 7.3 ± 4.9 min. The drug combination proved to be effective in the immobilization of free-ranging warthogs with rapid induction, good anesthesia, and limited cardiorespiratory changes. This anesthetic protocol produces effective, safe, and partially reversible immobilization in warthogs.

West Nile Virus in Wildlife and Nonequine Domestic Animals, South Africa, 2010-2018.

West Nile virus (WNV) lineage 2 is associated with neurologic disease in horses and humans in South Africa. Surveillance in wildlife and nonequine domestic species during 2010-2018 identified WNV in 11 (1.8%) of 608 animals with severe neurologic and fatal infections, highlighting susceptible hosts and risk for WNV epizootics in Africa.

Mycobacterium bovis Infection in African Wild Dogs, Kruger National Park, South Africa.

We screened African wild dogs (Lycaon pictus) in Kruger National Park, South Africa, for Mycobacterium bovis infection using an interferon-gamma release assay. We detected M. bovis sensitization in 20 of 21 packs; overall apparent infection prevalence was 83%. These animals experience high infection pressure, which may affect long-term survival and conservation strategies.

Compared to etorphine-azaperone, the ketamine-butorphanol-medetomidine combination is also effective at immobilizing zebra (Equus zebra).

OBJECTIVE: To compare immobilization efficacy of a nonpotent opioid drug combination, ketamine-butorphanol-medetomidine (KBM) to the preferred etorphine-azaperone (EA) combination in zebras. STUDY DESIGN: Randomized crossover trial. ANIMALS: A group of ten adult zebra (six females and four male). METHODS: KBM and EA were administered once to the zebras in random order by dart, 3 weeks apart. Once a zebra was recumbent and instrumented, physiological parameters were measured and recorded at 5-minute intervals until 20 minutes. Antagonist drugs were administered at 25 minutes. KBM was antagonised using atipamezole (7.5 mg mg-1 medetomidine dose) and naltrexone (2 mg mg-1 butorphanol dose). EA was antagonized using naltrexone (20 mg mg-1 etorphine dose). Induction and recovery (following antagonist administration) times were recorded. Physiological parameters, including invasive blood pressure and blood gas analysis, were compared between combinations using a general linear mixed model. Data are reported as mean ± standard deviation or median (interquartile range). RESULTS: The doses of KBM and EA administered were 3.30 ± 0.18, 0.40 ± 0.02 and 0.16 ± 0.01 mg kg-1; and 0.02 ± 0.001 and 0.20 ± 0.01 mg kg-1, respectively. KBM and EA induction times were 420 (282-564) and 240 (204-294) seconds, respectively (p = 0.03). Zebras remained recumbent throughout the study procedures. Systolic blood pressure (226 ± 42 and 167 ± 42 mmHg) and oxygen partial pressure (64 ± 12 and 47 ± 13 mmHg) were higher for KBM compared to EA (p < 0.01). Recovery time, after administering antagonists, was 92 (34-1337) and 26 (22-32) seconds for KBM and EA, respectively (p = 0.03). CONCLUSIONS AND CLINICAL RELEVANCE: Compared to EA, KBM also immobilized zebras effectively. Systemic hypertension and moderate hypoxaemia are clinical concerns of KBM and severe hypoxaemia is a concern of EA. This occurrence of hypoxaemia highlights the importance of oxygen administration during immobilization.

MYCOBACTERIUM BOVIS IN FREE-RANGING LIONS (PANTHERA LEO) - EVALUATION OF SEROLOGICAL AND TUBERCULIN SKIN TESTS FOR DETECTION OF INFECTION AND DISEASE.

Bovine tuberculosis (bTB), caused by Mycobacterium bovis infection, causes morbidity and mortality in free-ranging lions in bTB-endemic areas of South Africa. However, the only currently used diagnostic test is the tuberculin skin test (TST). This test is logistically challenging to perform because it requires immobilization of lions twice in a 72-hr period. Blood-based diagnostic tests, such as serological assays, have been previously reported for M. bovis detection in lion populations, and have the advantage of only requiring a single immobilization. In addition, serological assays can be used for retrospective testing. Therefore, the aim of this study was to test free-ranging lions with the STAT-PAKt (Chembio Diagnostics Systems, Medford, NY 11763, USA) and DPPt VetTB (Chembio Diagnostics Systems) serological assays and compare those results with the tuberculin skin test. The serological assays were also used to determine prevalence in bTB-endemic and uninfected lion populations. The results showed that the serological assays could distinguish between M. bovis culture-positive and -negative lions. In addition, antigen-specific humoral responses were present in lions that had clinical signs of bTB disease or were shedding M. bovis antemortem. Although the seroprevalence of M. bovis infection in Kruger National Park lions was similar to that obtained from antemortem mycobacterial culture (4.8 and 3.3%, respectively), it was less than that estimated by the TST (72%). These findings support the hypothesis that assays based on cell-mediated immune responses are more sensitive than serology is in detecting M. bovis infection in lions. However, serological assays can have a role in bTB disease detection in lions and are especially useful for retrospective studies.

Conservation of White Rhinoceroses Threatened by Bovine Tuberculosis, South Africa, 2016-2017.

During 2016-2017, when Kruger National Park, South Africa, was under quarantine to limit bovine tuberculosis spread, we examined 35 white and 5 black rhinoceroses for infection. We found 6 infected white rhinoceroses during times of nutritional stress. Further research on Mycobacterium bovis pathogenesis in white rhinoceroses is needed.