Periodontal health, neutrophil activity and cardiovascular health in captive chimpanzees.

OBJECTIVE: To investigate the association of dental and cardiac disease in a cohort of captive chimpanzees DESIGN: 12 captive chimpanzees underwent periodontal and cardiac examinations under anaesthesia during a relocation to a new enclosure. Blood samples were taken for analysis of circulating markers of cardiac health, nutritional status and isolation of neutrophils for functional assays. They were then observed for three years for signs of heart disease. RESULTS: Although the chimpanzees displayed large quantities of supragingival plaque, they had low bleeding scores. Peripheral blood neutrophils responded to innate and adaptive immune stimuli. In the follow up period two animals died and post mortem confirmed heart disease. Levels of NT-proBNP were found to be high in chimpanzees that died from heart disease. CONCLUSIONS: Whilst there appeared to be a correlation between probing depth and age, there appeared to be no correlation between dental data and heart data in this cohort.

Evaluation of the agreement of two oscillometric blood pressure devices with invasive blood pressure in anaesthetized chimpanzees (Pan troglodytes).

OBJECTIVE: To evaluate the agreement of two noninvasive blood pressure devices: a human device with the cuff placed on the wrist (Omron R1) and a veterinary device with the cuff placed on the upper brachium (Surgivet Advisor Vital Signs Monitor) with invasive blood pressure (IBP) measurement in anaesthetized chimpanzees. STUDY DESIGN: Prospective clinical study. ANIMALS: A convenience sample of 11 adult chimpanzees undergoing anaesthesia for translocation and routine health checks. METHODS: Systolic (SAP) and diastolic arterial pressures (DAP) were continuously recorded via a transducer connected to a femoral artery cannula, and at 5 minute intervals from the two oscillometric devices. Agreement was explored using Bland-Altman analysis and bias defined as the mean difference between the two measurement methods. Spearman correlation coefficients were calculated. Significance was set at p < 0.05. RESULTS: Bias and standard deviation for the Surgivet compared with IBP were 8.6 ± 18 for SAP and 8.4 ± 9.9 for DAP, showing a significant underestimation of both variables. Limits of agreement (LOA) were from -27 to 44 for SAP and from -11 to 28 for DAP. Correlation coefficients between the Surgivet and IBP values were 0.86 for SAP and 0.85 for DAP (p < 0.0001). Bias and standard deviation for the Omron compared with the IBP were -21 ± 25 for SAP and -18 ± 15 for DAP, showing a significant overestimation of both variables. LOA were from -70 to -28 for SAP and from -47 to 11 for DAP. Spearman correlation coefficients between the Omron and IBP values were 0.64 for SAP and 0.72 for DAP (p < 0.0001). CONCLUSIONS AND CLINICAL RELEVANCE: Although neither device met all the criteria for device validation, the Surgivet presented better agreement with IBP values than the Omron in adult anaesthetized chimpanzees.

Discovery of os cordis in the cardiac skeleton of chimpanzees (Pan troglodytes).

Cardiovascular diseases, especially idiopathic myocardial fibrosis, is one of the most significant causes of morbidity and mortality in captive great apes. This study compared the structure and morphology of 16 hearts from chimpanzees (Pan troglodytes) which were either healthy or affected by myocardial fibrosis using X-ray microtomography. In four hearts, a single, hyperdense structure was detected within the right fibrous trigone of the cardiac skeleton. High resolution scans and histopathology revealed trabecular bones in two cases, hyaline cartilage in another case and a focus of mineralised fibro-cartilaginous metaplasia with endochondral ossification in the last case. Four other animals presented with multiple foci of ectopic calcification within the walls of the great vessels. All hearts affected by marked myocardial fibrosis presented with bone or cartilage formation, and increased collagen levels in tissues adjacent to the bone/cartilage, while unaffected hearts did not present with os cordis or cartilago cordis. The presence of an os cordis has been described in some ruminants, camelids, and otters, but never in great apes. This novel research indicates that an os cordis and cartilago cordis is present in some chimpanzees, particularly those affected by myocardial fibrosis, and could influence the risk of cardiac arrhythmias and sudden death.

Comparison of 25-hydroxyvitamin D concentration in chimpanzee dried blood spots and serum.

BACKGROUND: Dried blood spots (DBS) are used in human medicine to measure total 25-hydroxyvitamin D (25-OHD) in the blood. However, this easy and affordable sampling technique has not been evaluated in primates to measure vitamin D concentrations. OBJECTIVES: We aimed to compare 25-OHD measurements in chimpanzee serum at two different laboratories and determine the precision and accuracy of the DBS method by comparing DBS and serum results. METHODS: Blood samples from 17 captive chimpanzees were collected, and 25-OHD3 and 25-OHD2 were measured in serum at two accredited laboratories using liquid chromatography-tandem mass spectrometry. The same analytes were measured on DBS cards, and results were compared with that of serum. Data were assessed using the Spearman correlation, Deming regression, and Bland-Altman analyses. RESULTS: The correlation coefficient between the two measurements in serum was rs  = .51 (P = .04), and the mean bias was -1.25 ± 14.83. When comparing 25-OHD concentrations measured in DBS and serum at the same laboratory, the rs was 0.7 (P = .002), and the mean bias was 1.42 ± 14.58. Estimated intra-assay and inter-assay coefficients of variation for DBS results were 6% and 12.6%, respectively. CONCLUSIONS: Although substantial analytical variability was found in 25-OHD measurements regardless of the sample type, the identification of both constant and proportional error and wider limits of agreement with the DBS technique makes the interpretation of DBS results challenging, especially for values close to clinical cut-off points. The DBS and serum methods were not interchangeable, and further studies are needed to validate DBS samples for vitamin D measurements in chimpanzees.

Idiopathic Myocardial Fibrosis in Captive Chimpanzees (Pan troglodytes).

Cardiovascular disorders and predominantly idiopathic myocardial fibrosis are frequently associated with mortality among zoo-housed chimpanzees (Pan troglodytes). Formalin-fixed whole hearts of deceased chimpanzees housed in zoos (n = 33) and an African sanctuary (n = 2) underwent detailed macroscopic and histopathologic examination using a standardized protocol. Archived histological slides from the hearts of 23 additional African sanctuary-housed chimpanzees were also examined. Myocardial fibrosis (MF) was identified in 30 of 33 (91%) of the zoo-housed chimpanzees but none of the 25 sanctuary-housed chimpanzees. MF was shown to be characterized by both interstitial and replacement fibrosis. Immunophenotyping demonstrated that the fibrotic lesions were accompanied by the increased presence of macrophages, alpha smooth muscle actin-positive myofibroblasts, and a minimal to mild T-cell-dominant leukocyte infiltration. There was no convincing evidence of cardiotropic viral infection or suggestion that diabetes mellitus or vitamin E or selenium deficiency were associated with the presence of the lesion. However, serum vitamin D concentrations among zoo-housed chimpanzees were found to be lower in seasons of low ultraviolet light levels.

A clinical study to evaluate the cardiopulmonary characteristics of two different anaesthetic protocols for immobilization of healthy chimpanzees (Pan troglodytes).

OBJECTIVE: To characterize the cardiopulmonary characteristics of two different anaesthetic protocols (tiletamine/zolazepam ± medetomidine) and their suitability for the immobilization of healthy chimpanzees undergoing cardiac assessment. STUDY DESIGN: Prospective, clinical, longitudinal study. ANIMALS: Six chimpanzees (Pan troglodytes) aged 4-16 years weighing 19.5-78.5 kg were anaesthetized on two occasions. METHODS: Anaesthesia was induced with tiletamine/zolazepam (TZ) (3-4 mg kg-1) or tiletamine/zolazepam (2 mg kg-1) and medetomidine (0.02 mg kg-1) (TZM) via blow dart [intramuscular (IM)] and maintained with intermittent boluses of ketamine (IV) or zolazepam/tiletamine (IM) as required. The overall quality of the anaesthesia was quantified based on scores given for: quality of induction, degree of muscle relaxation and ease of intubation. The time to achieve a light plane of anaesthesia, number of supplemental boluses needed and recovery characteristics were also recorded. Chimpanzees were continuously monitored and heart rate (HR), pulse rate (PR), respiratory rate (fR) oxygen saturation of haemoglobin (SpO2), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), rectal temperature, mucous membrane colour and capillary refill time recorded. During the first procedure (TZ) animals underwent a 12-channel electrocardiogram (ECG), haematology, biochemistry and cardiac biomarker assessment to rule out the presence of pre-existing cardiovascular disease. A detailed echocardiographic examination was carried out by the same blinded observer during both procedures. Data were compared using Student's paired t-test or Wilcoxon rank tests as appropriate. RESULTS: There was a significant difference for the area under the curves between anaesthetic protocols for HR, SAP, MAP and fR. No significant differences in the echocardiographic measurements were evident. Quality of anaesthesia was significantly better with TZM and no additional boluses were required. The TZ protocol required multiple supplemental boluses. CONCLUSIONS AND CLINICAL RELEVANCE: Both combinations are suitable for immobilization and cardiovascular evaluation of healthy chimpanzees. Further work is required to evaluate the effect of medetomidine in cardiovascular disease.

HEART RATE AND INDIRECT BLOOD PRESSURE RESPONSES TO FOUR DIFFERENT FIELD ANESTHETIC PROTOCOLS IN WILD-BORN CAPTIVE CHIMPANZEES (PAN TROGLODYTES).

Limited data are available on hemodynamic responses to anesthetic protocols in wild-born chimpanzees (Pan troglodytes). Accordingly, this study characterized the heart rate (HR) and blood pressure responses to four anesthetic protocols in 176 clinically healthy, wild-born chimpanzees undergoing routine health assessments. Animals were anesthetized with medetomidine-ketamine (MK) (n = 101), tiletamine-zolazepam (TZ) (n = 30), tiletamine-zolazepam-medetomidine (TZM) (n = 24), or medetomidine-ketamine (maintained with isoflurane) (MKI) (n = 21). During each procedure, HR, systolic blood pressure (SBP), and diastolic blood pressure (DBP) were regularly recorded. Data were grouped according to anesthetic protocol, and mean HR, SBP, and DBP were calculated. Differences between mean HR, SBP, and DBP for each anesthetic protocol were assessed using the Kruskall-Wallis test and a Dunn multiple comparisons post hoc analysis. To assess the hemodynamic time course response to each anesthetic protocol, group mean data (±95% confidence interval [CI]) were plotted against time postanesthetic induction. Mean HR (beats/min [CI]) was significantly higher in TZ (86 [80-92]) compared to MKI (69 [61-78]) and MK (62 [60-64]) and in TZM (73 [68-78]) compared to MK. The average SBP and DBP values (mm Hg [CI]) were significantly higher in MK (130 [126-134] and 94 [91-97]) compared to TZ (104 [96-112] and 58 [53-93]) and MKI (113 [103-123] and 78 [69-87]) and in TZM (128 [120-135] and 88 [83-93]) compared to TZ. Time course data were markedly different between protocols, with MKI showing the greatest decline over time. Both the anesthetic protocol adopted and the timing of measurement after injection influence hemodynamic recordings in wild-born chimpanzees and need to be considered when monitoring or assessing cardiovascular health.

SUMMER AND WINTER VITAMIN D3 LEVELS IN SEVEN PLATYRRHINE SPECIES HOUSED AT A BRITISH ZOO, WITH REFERENCE TO NATURAL UVB LEVELS.

Serum samples were collected from 24 platyrrhines of seven diurnal species housed with outdoor access at Bristol Zoo Gardens (United Kingdom) to test 25-hydroxyvitamin D3 (25OHD3) levels as part of the veterinary department's preventative health care program. Samples were collected in August 2008 (summer) and January 2009 (winter) to examine the effect of season on 25OHD3 levels. Dietary levels of vitamin D3 remained the same throughout the study period and fell within the range of 2000-4000 IU/kg dry matter, in accordance with current primate guidelines. Statistical analysis showed that there was no significant difference between the platyrrhines' summer 25OHD3 values (range, <4.0->150.0 µg/L) and winter 25OHD3 values (range, <4.0-80.1 µg/L). However, ultraviolet B (UVB) measurements taken at the zoo during the study period confirmed that UVB levels were significantly higher in summer (mean reading for 1200-1300 hours GMT time period, 153.8 µW/cm2) compared with winter (mean reading for 1200-1300 hours GMT time period, 19.4 µW/cm2). The 25OHD3 levels measured were generally found to be low compared with previously published values from healthy captive and wild platyrrhines.

A RETROSPECTIVE REVIEW OF WESTERN LOWLAND GORILLA (GORILLA GORILLA GORILLA) MORTALITY IN EUROPEAN ZOOLOGIC COLLECTIONS BETWEEN 2004 AND 2014.

An understanding of the main causes of mortality among captive gorillas is imperative to promoting their optimal care, health, and welfare. A retrospective observational review of mortality among the European zoo-housed western lowland gorilla ( Gorilla gorilla gorilla) population from 2004 to 2014 was carried out. This is the first published study of mortality in this population. Relevant postmortem data were requested from each collection reporting a death during the study period. Age at death enabled grouping into discrete age categories. Deaths were classified according to cause. The main causes of death overall and for each age category and sex were identified. In total, 151 gorillas from 50 European collections died during the study period. Postmortem data were available for 119 (79%) of the deaths, of which 102 (86%) were classified by cause. Diseases of the digestive system were responsible for most (23%) deaths overall. Also of significance (each accounting for 15% overall mortality) were deaths due to external causes (especially trauma) among young gorillas and cardiovascular disease among adult and aged animals. Being a male gorilla was associated with an 8.77- and 5.40-fold increase in risk of death due to cardiovascular and respiratory disease, respectively. Death due to external causes was 4.45 times more likely among females than males. There was no statistically significant difference in life expectancy between male and female gorillas. The authors conclude that further work is needed to understand risk factors involved in the main causes of death and suggest a need for standardization with regard the approach to postmortem examination and data collection, sample collection, and storage across European zoos.

Bilateral cataract surgery with intraocular lens implant in a captive western lowland gorilla.

We report a case of bilateral cataract surgery performed in a 21-year-old western lowland gorilla. Phacoemulsification with intraocular lens insertion was performed using standard human surgical equipment. Visual function significantly improved. She subsequently mated and gave birth. Ultimately, cataract surgery enabled the birth of a baby gorilla.

A SYSTEMATIC REVIEW OF THE LITERATURE RELATING TO CAPTIVE GREAT APE MORBIDITY AND MORTALITY.

Wild bonobos (Pan paniscus), chimpanzees (Pan troglodytes), Western gorillas (Gorilla gorilla), and orangutans (Pongo pygmaeus, Pongo abelii) are threatened with extinction. In order to help maintain a self-sustaining zoo population, clinicians require a sound understanding of the diseases with which they might be presented. To provide an up-to-date perspective on great ape morbidity and mortality, a systematic review of the zoological and veterinary literature of great apes from 1990 to 2014 was conducted. This is the first review of the great ape literature published since 1990 and the first-ever systematic literature review of great ape morbidity and mortality. The following databases were searched for relevant articles: CAB Abstracts, Web of Science Core Collection, BIOSIS Citation Index, BIOSIS Previews, Current Contents Connect, Data Citation Index, Derwent Innovations Index, MEDLINE, SciELO Citation Index, and Zoological Record. A total of 189 articles reporting on the causes of morbidity and mortality among captive great apes were selected and divided into comparative morbidity-mortality studies and case reports-series or single-disease prevalence studies. The content and main findings of the morbidity-mortality studies were reviewed and the main limitations identified. The case reports-case series and single-disease prevalence studies were categorized and coded according to taxa, etiology, and body system. Subsequent analysis allowed the amount of literature coverage afforded to each category to be calculated and the main diseases and disorders reported within the literature to be identified. This review concludes that reports of idiopathic and infectious diseases along with disorders of the cardiovascular, respiratory, and gastrointestinal body systems were particularly prominent within the great ape literature during 1990-2014. However, recent and accurate prevalence figures are lacking and there are flaws in those reviews that do exist. There is therefore a critical need for a robust, widespread, and more up-to-date review of mortality among captive great apes.

Simian Immunodeficiency Virus Infection of Chimpanzees (Pan troglodytes) Shares Features of Both Pathogenic and Non-pathogenic Lentiviral Infections.

The virus-host relationship in simian immunodeficiency virus (SIV) infected chimpanzees is thought to be different from that found in other SIV infected African primates. However, studies of captive SIVcpz infected chimpanzees are limited. Previously, the natural SIVcpz infection of one chimpanzee, and the experimental infection of six chimpanzees was reported, with limited follow-up. Here, we present a long-term study of these seven animals, with a retrospective re-examination of the early stages of infection. The only clinical signs consistent with AIDS or AIDS associated disease was thrombocytopenia in two cases, associated with the development of anti-platelet antibodies. However, compared to uninfected and HIV-1 infected animals, SIVcpz infected animals had significantly lower levels of peripheral blood CD4+ T-cells. Despite this, levels of T-cell activation in chronic infection were not significantly elevated. In addition, while plasma levels of ß2 microglobulin, neopterin and soluble TNF-related apoptosis inducing ligand (sTRAIL) were elevated in acute infection, these markers returned to near-normal levels in chronic infection, reminiscent of immune activation patterns in 'natural host' species. Furthermore, plasma soluble CD14 was not elevated in chronic infection. However, examination of the secondary lymphoid environment revealed persistent changes to the lymphoid structure, including follicular hyperplasia in SIVcpz infected animals. In addition, both SIV and HIV-1 infected chimpanzees showed increased levels of deposition of collagen and increased levels of Mx1 expression in the T-cell zones of the lymph node. The outcome of SIVcpz infection of captive chimpanzees therefore shares features of both non-pathogenic and pathogenic lentivirus infections.

SUMMER AND WINTER VITAMIN D3 LEVELS IN FOUR LEMUR SPECIES HOUSED AT A BRITISH ZOO, WITH REFERENCE TO UVB LEVELS.

Serum samples were collected from 18 lemurs of four diurnal/cathemeral species housed with outdoor access at Bristol Zoo Gardens (United Kingdom) to test 25-hydroxy-vitamin D3 (25OHD3) levels as part of the veterinary department's preventative health care program. Samples were collected from each lemur in August 2008 (summer) and January 2009 (winter) to examine the effect of season on 25OHD3 levels. The lemurs were fed commercial primate food and a range of fruit and vegetables, and dietary levels of vitamin D3 remained the same throughout the study period. Statistical analysis showed that the lemurs' summer 25OHD3 values (range 26.7 to >150.0 µg/L) were significantly higher than their winter 25OHD3 values (range 11.4-87.1 µg/L). UVB measurements taken during the study period confirmed that UVB levels were significantly higher in summer (mean reading for 1200-1300 GMT time period 153.8 µW/cm2) compared to winter (mean reading for 1200-1300 GMT time period 19.4 µW/cm2). The 25OHD3 levels measured were generally found to be high compared to previously published values from wild (free-ranging) lemurs in Madagascar. The most likely explanation for this was the higher vitamin D3 content of the captive lemurs' diet, as UVB levels at the zoo (latitude 51° north) are substantially lower than those that occur in Madagascar (latitude 12°-26° south). No evidence of vitamin D toxicity or deficiency was found in any of the captive lemurs. The results indicate that vitamin D3 levels in lemurs housed with outdoor access in the United Kingdom and by extension, other regions of similar latitude, vary with seasonal environmental UVB levels, in a similar way to the seasonal variations in vitamin D3 observed in humans living in these regions, but that vitamin D levels in this captive lemur population were adequate compared to wild lemur levels, even in winter.

First fatality associated with elephant endotheliotropic herpesvirus 5 in an Asian elephant: pathological findings and complete viral genome sequence.

Infections of Asian elephants (Elephas maximus) with elephant endotheliotropic herpesvirus (EEHV) can cause a rapid, highly lethal, hemorrhagic disease, which primarily affects juvenile animals up to the age of four years. So far, the majority of deaths have been attributed to infections with genotype EEHV1 or, more rarely, EEHV3 and EEHV4. Here, we report the pathological characteristics of the first fatality linked to EEHV5 infection, and describe the complete viral DNA sequence. Gross post-mortem and histological findings were indistinguishable from lethal cases previously attributed to other EEHV genotypes, and the presence of characteristic herpesviral inclusions in capillary endothelial cells at several sites was consistent with the diagnosis of acute EEHV infection. Molecular analysis confirmed the presence of EEHV5 DNA and was followed by sequencing of the viral genome directly from post-mortem material. The genome is 180,800 bp in size and contains 120 predicted protein-coding genes, five of which are fragmented and presumably nonfunctional. The seven families of paralogous genes recognized in EEHV1 are also represented in EEHV5. The overall degree of divergence (37%) between the EEHV5 and EEHV1 genomes, and phylogenetic analysis of eight conserved genes, support the proposed classification of EEHV5 into a new species (Elephantid herpesvirus 5).

Pneumonia from Angiostrongylus vasorum infection in a red panda (Ailurus fulgens fulgens).

A 9-year-old, male, captive red panda (Ailurus fulgens fulgens) in an urban zoo in the United Kingdom presented with respiratory distress and weight loss. The animal was euthanatized, and a postmortem examination was performed. The lungs were diffusely consolidated with extensive mineralization. Microscopically, there was extensive obliteration of normal pulmonary architecture by sheets and coalescing nodules of partially mineralized fibrous tissue and granulomatous inflammation centered on large numbers of nematode larvae and eggs. First stage nematode larvae were isolated from lung tissue and were characterized as Angiostrongylus vasorum on the basis of their morphology and sequencing of the 18S ribosomal RNA gene and the entire second internal transcribed spacer. Although A. vasorum has previously been reported in red pandas in a zoological collection in Denmark, this study is the first reported case in the United Kingdom and occurs against a background of geographical spread and increased incidence of disease in domestic and wild canids. Angiostrongylus vasorum should be considered a differential diagnosis for respiratory disease in the red panda and taken into account when planning parasite and pest control programs for zoological collections.