Publications (47)75.01 Total impact
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Article: Reproductive seasonality in captive wild ruminants: implications for biogeographical adaptation, photoperiodic control, and life history.
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ABSTRACT: Many ruminant species show seasonal patterns of reproduction. Causes for this are widely debated, and include adaptations to seasonal availability of resources (with cues either from body condition in more tropical, or from photoperiodism in higher latitude habitats) and/or defence strategies against predators. Conclusions so far are limited to datasets with less than 30 species. Here, we use a dataset on 110 wild ruminant species kept in captivity in temperate-zone zoos to describe their reproductive patterns quantitatively [determining the birth peak breadth (BPB) as the number of days in which 80% of all births occur]; then we link this pattern to various biological characteristics [latitude of origin, mother-young-relationship (hider/follower), proportion of grass in the natural diet (grazer/browser), sexual size dimorphism/mating system], and compare it with reports for free-ranging animals. When comparing taxonomic subgroups, variance in BPB is highly correlated to the minimum, but not the maximum BPB, suggesting that a high BPB (i.e. an aseasonal reproductive pattern) is the plesiomorphic character in ruminants. Globally, latitude of natural origin is highly correlated to the BPB observed in captivity, supporting an overruling impact of photoperiodism on ruminant reproduction. Feeding type has no additional influence; the hider/follower dichotomy, associated with the anti-predator strategy of 'swamping', has additional influence in the subset of African species only. Sexual size dimorphism and mating system are marginally associated with the BPB, potentially indicating a facilitation of polygamy under seasonal conditions. The difference in the calculated Julian date of conception between captive populations and that reported for free-ranging ones corresponds to the one expected if absolute day length was the main trigger in highly seasonal species: calculated day length at the time of conception between free-ranging and captive populations followed a y = x relationship. Only 11 species (all originating from lower latitudes) were considered to change their reproductive pattern distinctively between the wild and captivity, with 10 becoming less seasonal (but not aseasonal) in human care, indicating that seasonality observed in the wild was partly resource-associated. Only one species (Antidorcas marsupialis) became more seasonal in captivity, presumably because resource availability in the wild overrules the innate photoperiodic response. Reproductive seasonality explains additional variance in the body mass-gestation period relationship, with more seasonal species having shorter gestation periods for their body size. We conclude that photoperiodism, and in particular absolute day length, are genetically fixed triggers for reproduction that may be malleable to some extent by body condition, and that plasticity in gestation length is an important facilitator that may partly explain the success of ruminant radiation to high latitudes. Evidence for an anti-predator strategy involving seasonal reproduction is limited to African species. Reproductive seasonality following rainfall patterns may not be an adaptation to give birth in periods of high resource availability but an adaptation to allow conception only at times of good body condition.Biological Reviews 07/2012; 87(4):965-990. · 9.07 Impact Factor -
Article: Comparing life expectancy of three deer species between captive and wild populations
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ABSTRACT: Life in zoological gardens provides a number of benefits to captive animals, resulting in an artificial reduction of the “struggle Life in zoological gardens provides a number of benefits to captive animals, resulting in an artificial reduction of the “struggle for life” compared to their free-ranging counterparts. These advantages should result in a higher chance of surviving from for life” compared to their free-ranging counterparts. These advantages should result in a higher chance of surviving from 1year to the next, and thus in longer average life expectancies for captive animals, given that the biological requirements 1year to the next, and thus in longer average life expectancies for captive animals, given that the biological requirements of the species are adequately met. Here, we compare the life expectancy of captive and free-ranging populations of three deer of the species are adequately met. Here, we compare the life expectancy of captive and free-ranging populations of three deer species (reindeer Rangifer tarandus, red deer Cervus elaphus, and roe deer Capreolus capreolus). Whereas captive reindeer and red deer had life expectancies equal to or longer than free-ranging individuals, the life species (reindeer Rangifer tarandus, red deer Cervus elaphus, and roe deer Capreolus capreolus). Whereas captive reindeer and red deer had life expectancies equal to or longer than free-ranging individuals, the life expectancy of captive roe deer was shorter than that of free-ranging animals. These results support the impression that roe expectancy of captive roe deer was shorter than that of free-ranging animals. These results support the impression that roe deer are difficult to keep in zoos, whereas reindeer and red deer perform well under human care. We suggest that the mean deer are difficult to keep in zoos, whereas reindeer and red deer perform well under human care. We suggest that the mean life expectancy of captive populations relative to that of corresponding free-ranging populations is a reliable indicator life expectancy of captive populations relative to that of corresponding free-ranging populations is a reliable indicator to evaluate the husbandry success of a species in captivity. to evaluate the husbandry success of a species in captivity. Keywords Keywords Capreolus capreolus Capreolus capreolus - - Cervus elaphus Cervus elaphus -Husbandry-Longevity- -Husbandry-Longevity- Rangifer tarandus Rangifer tarandus -Sex differences -Sex differencesEuropean Journal of Wildlife Research 04/2012; 56(2):205-208. · 1.31 Impact Factor -
Article: An isthmus at the caecocolical junction is an anatomical feature of domestic and wild equids
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ABSTRACT: The isthmus at the caecocolical junction in domestic equids is well described. Like another isthmus between the ansa proximalis coli (the colonic fermentation chamber or ‘large colon’) and the colon transversum (the distal or ‘small’ colon), this spot represents not only a potential anatomical feature contributing to particle ingesta retention but also an explicit predilection site for intestinal obstructions. The question whether this anatomical feature also occurs in wild equids is therefore of both physiological and medical interest but has not been addressed so far. In this paper, we report dissections of the large intestine of a domestic pony (Equus caballus f. dom.), a Przewalski horse (Equus przewalski) and a plains zebra (Equus burchelli). The intestinal tract section of all three animals were similar in length; each species displayed the caecocolical isthmus as well as the abrupt narrowing of the intestinal tract between the ‘large’ and the ‘small’ colon. Graphical descriptions of wild equid gastrointestinal anatomy should include these features.European Journal of Wildlife Research 04/2012; 54(2):347-351. · 1.31 Impact Factor -
Article: Observations on the length of the intestinal tract of African Loxodonta africana (Blumenbach 1797) and Asian elephants Elephas maximus (Linné 1735)
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ABSTRACT: The digestive tract of elephants is surprisingly short compared to other herbivorous mammals. However, measurements relating the length of the intestine to the body mass of the respective individual are rare. In this study, we report such data for an African elephant and an Asian elephant. Our data support the hypothesis that Asian elephants have a longer intestinal tract than their African counterparts. These findings are in accord with the observation of longer retention times and higher digestion coefficients in Asian as compared to African elephants. This difference between the species could be the reflection of slightly different ecological niches, with Asian elephants adapted to a natural diet with a higher proportion of grass.European Journal of Wildlife Research 04/2012; 53(1):68-72. · 1.31 Impact Factor -
Article: Fluid and particle retention times in the black rhinocerosDiceros bicornis, a large hindgut-fermenting browser
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ABSTRACT: 2005. Fluid and particle retention times in the black rhinoceros Diceros bicornis, a large hindgut-fermenting browser. Acta Theriologica 50: 367-376. The mean retention time (MRT) of ingesta in the gastrointestinal tract is one of the major determinants of herbivore digestive physiology. We examined MRTs of fluids and particles in the gastrointestinal tract of six adult captive black rhinoceroses Diceros bicornis on conventional zoo diets. Fluid MRT ranged from 25-45 h and averaged 31 h. Particle MRT ranged froin 28-59 h and averaged 38 h. In the six animals, both fluid and particle MRT declined as relative dry matter intake (g/kg metabolic body mass) increased. Black rhinoceroses, which are large hindgut--fermenting browsers, retained ingesta for a shorter period relative to their body size than grazing equids or grazing rhinoceros species. Our findings support the hypothesis that browsing hindgut fermenters have relatively shorter MRTs than grazing hindgut fermenters.Acta theriologica 04/2012; 50(3). · 0.89 Impact Factor -
Article: Variation in Growth and Potentially Associated Health Status in Hermann's and Spur-Thighed Tortoise (Testudo hermanni and Testudo graeca).
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ABSTRACT: Captive reptiles often show higher growth rates than in the wild, possibly due to higher feeding intensity. Although health problems are usually linked to inappropriate diets, fast growth itself, such as triggered by appropriate diets fed in high amounts, has traditionally also been considered unfavorable for tortoises. We document growth rates (based on age and mass) from private Testudo hermanni and T. graeca breeders, which are generally higher than those reported for free-ranging specimens, but show enormous variation. Tortoise patients presented to an exotics clinic also covered the whole growth rate spectrum. To test whether fast growth was associated with diseases, the age-body mass relationship of these patients was tested, in a retrospective evaluation, for additional influence factors, such as dietary history and occurrence of certain diet and growth-related diseases. No indication was found that animals particularly heavy for their age were more prone to diet/growth-related disorders. In general, tortoises fed diets with meat/grain were heavier for their age than tortoises fed more appropriate diets; dietary history was not related to a particular disease. The results suggest the age-body mass relationship may not be suitable for testing effects of fast growth; an age-body length relationship would be more appropriate. Animals presented for a diet/growth-related disorder were younger than animals presented for other reasons; there was a significant negative correlation between the severity of pyramiding and age, suggesting that growth-related disorders may well limit the life expectancy of tortoises. Controlled clinical studies are required to fully test this hypothesis.Zoo Biology 01/2012; · 0.84 Impact Factor -
Article: Use of deferiprone for the treatment of hepatic iron storage disease in three hornbills.
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ABSTRACT: 3 hornbills (2 Papua hornbills [Aceros plicatus] and 1 longtailed hornbill [Tockus albocristatus]) were evaluated because of general listlessness and loss of feather glossiness. Because hepatic iron storage disease was suspected, liver biopsy was performed and formalin-fixed liver samples were submitted for histologic examination and quantitative image analysis (QIA). Additional frozen liver samples were submitted for chemical analysis. Birds also underwent magnetic resonance imaging (MRI) under general anesthesia for noninvasive measurement of liver iron content. Serum biochemical analysis and analysis of feed were also performed. Results of diagnostic testing indicated that all 3 hornbills were affected with hepatic iron storage disease. The iron chelator deferiprone was administered (75 mg/kg [34.1 mg/lb], PO, once daily for 90 days). During the treatment period, liver biopsy samples were obtained at regular intervals for QIA and chemical analysis of the liver iron content and follow-up MRI was performed. In all 3 hornbills, a rapid and large decrease in liver iron content was observed. All 3 methods for quantifying the liver iron content were able to verify the decrease in liver iron content. Orally administered deferiprone was found to effectively reduce the liver iron content in these 3 hornbills with iron storage disease. All 3 methods used to monitor the liver iron content (QIA, chemical analysis of liver biopsy samples, and MRI) had similar results, indicating that all of these methods should be considered for the diagnosis of iron storage disease and monitoring of liver iron content during treatment.Journal of the American Veterinary Medical Association 01/2012; 240(1):75-81. · 1.79 Impact Factor -
Article: Radiographic measurement of internal organs in Spix's macaws (Cyanopsitta spixii).
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ABSTRACT: Radiology is an important diagnostic instrument in avian medicine, but standard measurement ranges for the objective evaluation of radiographs of birds are rare. To establish radiographic reference ranges for the critically endangered Spix's macaw (Cyanopsitta spixii), we measured radiographic silhouettes of the heart, liver, kidneys, spleen, proventriculus, and keel of the sternum on 29 radiographs taken under standardized conditions in adult and juvenile, clinically healthy birds. Ratios were determined for the proventricular diameter-to-keel height, the width of the heart to the width of the thorax, and for the "hourglass shape" (ratio of the width of the heart to the width of the liver). No significant differences were found between the sexes among the adult birds. Compared with adult birds, juvenile females had a significantly larger heart width (19.8 +/- 1.4 mm versus 21.2 +/- 0.7 mm), ratio of the heart width to the thorax width (0.86 +/- 0.08 versus 0.94 +/- 0.09), and horizontal width of the spleen (7.7 +/- 0.6 mm versus 8.5 +/- 0.4 mm). Results of radiographic measurements in the Spix's macaws were comparable to those published from other psittacine species. These reference ranges will facilitate a more objective radiographic evaluation of captive Spix's macaws.Journal of Avian Medicine and Surgery 12/2011; 25(4):254-8. · 0.63 Impact Factor -
Article: Ultrasonographic evaluation of postprandial heart variation in juvenile Paraguay anacondas (Eunectes notaeus).
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ABSTRACT: To noninvasively evaluate physiologic postprandial adaptations of the heart in snakes. 6 juvenile Paraguay anacondas (Eunectes notaeus). The heart of each anaconda was echocardiographically evaluated after food was withheld for 28 days as well as 3 and 10 days after feeding. Physical measurements included body length, weight, and circumference at the level of the heart. Echocardiographic measurements included heart rate and 2-D total and internal ventricular area. From these measurements, total ventricular volume as well as the myocardial area as a surrogate of myocardial mass was calculated. No significant changes in body length, weight, and circumference were found. Significant increases in heart rate (from 45 to 58 beats/min), total ventricular volume (from 4.63 to 5.54 mL), and myocardial area (from 0.7 to 0.81 cm(2)) were detected 10 days after feeding, compared with results obtained prior to feeding after food had been withheld for 28 days. No pericardial effusion was detected at any time point. Echocardiographic evaluation of the heart of anacondas was performed, and feeding resulted in concentric cardiac hypertrophy. Physiologic fluctuation of cardiac dimensions should be considered when cardiac imaging is performed in snakes.American Journal of Veterinary Research 09/2011; 72(9):1253-8. · 1.27 Impact Factor -
Article: Bispectral index reveals death-feigning behavior in a red kite (Milvus milvus).
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ABSTRACT: Red kites (Milvus milvus) are birds of prey known to feign death in the presence of humans. An adult wild red kite was anesthetized with isoflurane for coelioscopy. During surgery, heart rate and respiratory rate ranged from 240 to 260 beats per minute and from 16 to 28 breaths rates per minute, respectively. Pupil and corneal reflexes remained present, and body temperature was maintained at 40.4 degrees C (104.7 degrees F). Suppression ratio was 0 during the anesthetic episode. The bispectral index was 44 immediately after intubation, ranged from 44 to 57 during maintenance of anesthesia, and was 59 at the moment of extubation. The index increased to 85 while the kite remained immobile, which was suggestive of feigning death in sternal recumbency. Once the bird was perched upright, it immediately kept the upright position, which confirmed the correspondence of the bispectral index value (85) with a fully conscious patient. Although behavioral or cardiorespiratory variables remained unchanged, the degree of hypnosis was indicated by the bispectral index, which anticipated a possible sudden awakening episode of this bird.Journal of Avian Medicine and Surgery 06/2011; 25(2):132-5. · 0.63 Impact Factor -
Article: Methane output of tortoises: its contribution to energy loss related to herbivore body mass.
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ABSTRACT: An increase in body mass (M) is traditionally considered advantageous for herbivores in terms of digestive efficiency. However, recently increasing methane losses with increasing M were described in mammals. To test this pattern in non-mammal herbivores, we conducted feeding trails with 24 tortoises of various species (M range 0.52-180 kg) fed a diet of grass hay ad libitum and salad. Mean daily dry matter and gross energy intake measured over 30 consecutive days scaled to M(0.75 (95%CI 0.64-0.87)) and M(0.77 (95%CI 0.66-0.88)), respectively. Methane production was measured over two consecutive days in respiration chambers and scaled to M(1.03 (95%CI 0.84-1.22)). When expressed as energy loss per gross energy intake, methane losses scaled to 0.70 (95%CI 0.47-1.05) M(0.29 (95%CI 0.14-0.45)). This scaling overlaps in its confidence intervals to that calculated for nonruminant mammals 0.79 (95%CI 0.63-0.99) M(0.15 (95%CI 0.09-0.20)), but is lower than that for ruminants. The similarity between nonruminant mammals and tortoises suggest a common evolution of the gut fauna in ectotherms and endotherms, and that the increase in energetic losses due to methane production with increasing body mass is a general allometric principle in herbivores. These findings add evidence to the view that large body size itself does not necessarily convey a digestive advantage.PLoS ONE 01/2011; 6(3):e17628. · 4.09 Impact Factor -
Article: Herbivorous reptiles and body mass: effects on food intake, digesta retention, digestibility and gut capacity, and a comparison with mammals.
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ABSTRACT: Differences in the allometric scaling between gut capacity (with body mass, BM¹·⁰⁰) and food intake (with BM⁰·⁷⁵) should theoretically result in a scaling of digesta retention time with BM⁰·²⁵ and therefore a higher digestive efficiency in larger herbivores. This concept is an important part of the so-called 'Jarman-Bell principle' (JBP) that explains niche differentiation along a body size gradient in terms of digestive physiology. Empirical data in herbivorous mammals, however, do not confirm the scaling of retention time, or of digestive efficiency, with body mass. Here, we test these concepts in herbivorous reptiles, adding data of an experiment that measured food intake, digesta retention, digestibility and gut capacity in 23 tortoises (Testudo graeca, T. hermanni , Geochelone nigra, G. sulcata, Dipsochelys dussumieri) across a large BM range (0.5-180 kg) to a literature data collection. While dry matter gut fill scaled to BM¹·⁰⁷ and dry matter intake to BM⁰·⁷⁶, digesta mean retention time (MRT) scaled to BM⁰·¹⁷; the scaling exponent was not significantly different from zero for species > 1 kg. Food intake level was a major determinant of MRT across reptiles and mammals. In contrast to dietary fibre level, BM was not a significant contributor to dry matter digestibility in a General Linear Model. Digestibility coefficients in reptiles depended on diet nutrient composition in a similar way as described in mammals. Although food intake is generally lower and digesta retention longer in reptiles than in mammals, digestive functions scale in a similar way in both clades, indicating universal principles in herbivore digestive physiology. The reasons why the theoretically derived JBP has little empirical support remain to be investigated. Until then, the JBP should not be evoked to explain niche differentiation along a body size axis in terms of digestive physiology.Comparative biochemistry and physiology. Part A, Molecular & integrative physiology 01/2011; 158(1):94-101. · 2.20 Impact Factor -
Article: Mating system, feeding type and ex situ conservation effort determine life expectancy in captive ruminants.
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ABSTRACT: Zoo animal husbandry aims at constantly improving husbandry, reproductive success and ultimately animal welfare. Nevertheless, analyses to determine factors influencing husbandry of different species are rare. The relative life expectancy (rLE; life expectancy (LE) as proportion of longevity) describes husbandry success of captive populations. Correlating rLE with biological characteristics of different species, reasons for variation in rLE can be detected. We analysed data of 166 901 animals representing 78 ruminant species kept in 850 facilities. The rLE of females correlated with the percentage of grass in a species' natural diet, suggesting that needs of species adapted to grass can be more easily accommodated than the needs of those adapted to browse. Males of monogamous species demonstrate higher rLE than polygamous males, which matches observed differences of sexual bias in LE in free-living populations and thus supports the ecological theory that the mating system influences LE. The third interesting finding was that rLE was higher in species managed by international studbooks when compared with species not managed in this way. Our method facilitates the identification of biological characteristics of species that are relevant for their husbandry success, and they also support ecological theory. Translating these findings into feeding recommendations, our approach can help to improve animal husbandry.Proceedings of the Royal Society B: Biological Sciences 12/2010; 278(1714):2076-80. · 5.41 Impact Factor -
Article: Evaluation of butorphanol, medetomidine and midazolam as a reversible narcotic combination in free-ranging African lions (Panthera leo).
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ABSTRACT: To evaluate the effects of the combination butorphanol, medetomidine and midazolam (BMM) and its reversibility in lions. Prospective clinical trial. Thirty free-ranging lions, 10 male and 20 female, weighing 81-210 kg. Lions were immobilised with butorphanol mean 0.31 ± SD 0.034 mg kg(-1), medetomidine 0.052 ± 0.006 mg kg(-1), midazolam 0.21 ± 0.024 mg kg(-1) and hyaluronidase 1250 IU administered intramuscularly with a dart gun. Upon recumbency, physiological parameters and anaesthetic depth were monitored 10-15 minutes after darting (T1) and repeated every 10 minutes for a further 30 minutes (T2, T3, T4). Arterial blood gas analyses were performed at T1 and T4. At the end of the procedure, 45-60 minutes after initial darting, immobilisation was reversed with naltrexone 0.68 ± 0.082 mg kg(-1), atipamezole 0.26 ± 0.031 mg kg(-1), and flumazenil 0.0032 ± 0.0007 mg kg(-1) administered intravenously and subcutaneously. The BMM combination rapidly induced immobilisation and lateral recumbency was reached within 7.25 ± 2.3 minutes. Median induction score [scored 1 (excellent) to 4 (poor)] was 1.4 (range 1-2). Cardio-respiratory parameters were stable. Heart rate varied from 32 to 72 beats per minute, respiratory rate from 14 to 32 breaths minute(-1) and rectal temperature from 36.6 to 40.3 °C. No sudden arousals were observed. Arterial blood gas analyses revealed a mean pH of 7.33, PaCO(2) of 33 mmHg and PaO(2) of 87 mmHg. Mild to moderate hypoxemia was seen in four lions. Recovery was smooth and lions were walking within 4.4 ± 4.25 minutes. Median recovery score [scored 1 (excellent) to 4 (poor)] was 1.3 (range 1-2). The drug combination proved to be effective in immobilising free-ranging healthy lions of both sexes with minimal cardio-respiratory changes.Veterinary Anaesthesia and Analgesia 11/2010; 37(6):491-500. · 0.94 Impact Factor -
Article: Clinical course of a malignant peripheral nerve sheath tumor in a Siberian tiger (Panthera tigris altaica).
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ABSTRACT: A 14-year-old male Siberian tiger (Panthera tigris altaica) was admitted with an ulcerating mass on the right thoracic wall. Radiographic and computed tomographic evaluation indicated 2 isolated cutaneous masses without any signs of metastasis. Histology of a Tru-Cut biopsy revealed an anaplastic sarcoma with giant cells. Both tumors were resected with appropriate normal tissue margins. The size of the defect did not allow primary closure of the wound; therefore, a mesh expansion technique was attempted. Three months later, the tiger had to be euthanized due to extensive metastasis to the lungs. Histomorphological features and immunohistochemical results confirmed the diagnosis of malignant peripheral nerve sheath tumor. In contrast to domestic animal experience, the tumor had spread extensively to the lungs without local reccurrence in a short period of time. Correct diagnosis requires various immunohistochemical evaluations of the tumor tissue.Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc 11/2010; 22(6):970-5. · 1.21 Impact Factor -
Article: CASE REPORT: Bilateral vision loss in a captive cheetah (Acinonyx jubatus)
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ABSTRACT: The following case report describes a 1-year-old female cheetah (Acinonyx jubatus) with bilateral blindness and unresponsive pupils. For comparison, a second healthy 2.5-year-old male cheetah without visual deficits was also examined. Clinical examination of both animals included biomicroscopy, indirect ophthalmoscopy, tonometry, and electroretinography. The young female cheetah showed no menace response, no direct or indirect pupillary light reflex, and no dazzle reflex in either eye. Fundus lesions, as detected by indirect ophthalmoscopy, are described for the female animal. In both eyes, the fundus color was green/turquoise/yellow with multiple hyperpigmented linear lesions in the tapetal area around the optic nerve. The optic nerve head was dark gray and about half the normal size suggesting bilateral optic nerve hypoplasia and retinal dysplasia or differentially optic nerve atrophy and chorioretinal scarring. The ERG had low amplitudes in the right eye but appeared normal in the left eye compared with the male cheetah. Blood levels did not suggest current taurine deficiency. This is addressed to some degree in the discussion. Bilateral optic nerve hypoplasia or optic nerve atrophy is a rare anomaly in cats and has not yet been described in a cheetah.Veterinary Ophthalmology 09/2010; 13(s1):128 - 133. · 0.75 Impact Factor -
Article: Analysis of exhaled breath condensate in a mixed population of psittacine birds.
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ABSTRACT: Collection of exhaled breath condensate (EBC) and the measurement of inflammatory markers contained therein (eg, hydrogen peroxide [H2O2], leukotriene B4 [LTB4], and pH) have been reported to be noninvasive tools for the investigation of respiratory disease in various species. In this study, the EBC of clinically healthy psittacine birds (n = 15) and psittacine birds with respiratory tract disease (n = 19) was examined, and inflammatory markers contained in the EBC were analyzed and compared. Awake birds were placed in an acrylic container from which the outflow passed through a condensation system that collected the EBC. All samples were analyzed for pH, H2O2, and LTB4. The mean values for each of these components, as well as the mean volume of the total EBC, measured from the apparently healthy birds did not differ significantly from those measured in birds with signs of respiratory tract disease. However, LTB4 in the EBC of diseased birds was higher than that of the apparently healthy birds and showed a trend toward significance. The study demonstrated the establishment of a standardized method for collecting and analyzing EBC in psittacine birds and a measurement protocol for pH, H2O2, and LTB4.Journal of Avian Medicine and Surgery 09/2010; 24(3):185-91. · 0.63 Impact Factor -
Article: Emergence and establishment of Usutu virus infection in wild and captive avian species in and around Zurich, Switzerland--genomic and pathologic comparison to other central European outbreaks.
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ABSTRACT: In late summer 2006 considerable mortality in wild and captive Passeriformes and Strigiformes was observed in Zurich, Switzerland. All animals were found in a range of 2 km(2). Observed clinical signs involved depression, ruffled plumage, incoordination, seizures and peracute death. Nutritional status was generally moderate to poor in wild birds, and variable in captive animals. Necropsy showed marked splenomegaly, a mild hepatomegaly, and pulmonary hyperemia in most animals. Histopathologic lesions were very discrete and consisted mainly of neuronal necrosis, leucocytolysis in and around the brain blood vessels, and miliary liver necrosis. The diagnosis Usutu virus (USUV) infection was established by USUV-specific immunohistochemistry and reverse transcription-polymerase chain reaction. Partial nucleotide sequence comparisons revealed>99% identity between the viruses that emerged in Zurich in 2006, in Vienna in 2001, and in Budapest in 2005. Since 2008 a significantly lower mortality was observed in wild Passeriformes, but USUV infection was confirmed for the first time beyond Zurich city limits. Indoor housing and regular treatment against ectoparasites are likely to have prevented acute USUV disease in captive Strigiformes. USUV is a mosquito-borne flavivirus causing fatalities in various avian species. After the initial European outbreaks in Austria in 2001 it appears that the virus has extended its range in Central Europe and has established a transmission cycle between local bird and mosquito species. Further episodes of increased avian mortality in the forthcoming years, with impact on wild and captive bird populations, predominantly Passeriformes and Strigiformes, can be anticipated. Furthermore, the possibility of broader dispersal of USUV in Europe during the next mosquito seasons must be considered and an increased mortality in Passeriformes and Strigiformes must be expected until protective "flock immunity" is established. Collections of valuable and endangered Passeriformes and Strigiformes, especially young of the year, should therefore be housed indoors or treated against ectoparasites at acceptable intervals between July and September each year.Veterinary Microbiology 09/2010; 148(2-4):207-12. · 3.33 Impact Factor -
Article: Investigations on the diagnosis and retroviral aetiology of renal neoplasia in budgerigars (Melopsittacus undulatus).
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ABSTRACT: The high susceptibility of budgerigars (Melopsittacus undulatus) to neoplasia, and specifically renal neoplasia, has often been reported. Further investigations led to a suspicion of a retrovirus as the causative agent for renal neoplasia in budgerigars, but definitive proof has yet to be found. In the present study, 32 budgerigars suspected of having renal neoplasia (based on the clinical presentation) were examined. The objectives were to investigate the use of different diagnostic methods for the ante-mortem diagnosis of this condition and to find more supporting evidence of a retroviral aetiology. The predominant clinical signs observed in budgerigars with renal neoplasia were lameness and absence of deep pain sensation of one leg. Alterations in haematology, plasma chemistry, and urine analyses could not pinpoint the cases of renal neoplasia. Contrast radiography of the intestinal tract proved to be diagnostically more useful compared with plain radiographic studies. Histology confirmed the renal neoplasia as adenocarcinoma. Investigations for virus identification included product-enhanced reverse transcriptase assay and enzyme-linked immunosorbent assay for the detection of avian leucosis virus group-specific antigen. Cell cultures and electron microscopy were performed on a limited number of patients. These investigations could find no presence of an exogenous, replicating retrovirus, neither could viral particles be detected by electron microscopy. Based on the current findings, it can be concluded that there is no evidence of retroviral involvement in the occurrence of renal neoplasia in budgerigars.Avian Pathology 06/2010; 39(3):161-7. · 1.71 Impact Factor -
Article: Fallot's tetralogy in a European beaver (Castor fiber).
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ABSTRACT: A 20-mo-old, female, 9-kg European beaver (Castor fiber) presented with apathy, reduced appetite of 3-day duration and a grade 5/6 systolic heart murmur. Thoracic radiographs revealed a diffuse broncho-interstitial pattern suspicious for bronchopneumonia. The echocardiographic findings of a hypertrophied right ventricle, ventricular septal defect with overriding aorta, and infundibular pulmonic stenosis were consistent with Fallot's tetralogy. Even though the bronchopneumonia rather than the congenital cardiac defect was considered of primary importance for the presenting clinical signs, the latter was relevant for the decision not to continue any medical treatment. Both disease processes were confirmed on necropsy. Fallot's tetralogy, European beaver, Castor fiber, heart murmur, ultrasound.Journal of Zoo and Wildlife Medicine 06/2010; 41(2):359-62. · 0.38 Impact Factor
Top co-authors
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Institutions
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2012
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Rheinische Friedrich-Wilhelms-Universität Bonn
Bonn, North Rhine-Westphalia, Germany
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1998–2010
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Universität Zürich
- • Vetsuisse-Faculty
- • Clinic of Zoo Animals, Exotic Pets and Wildlife
Zürich, ZH, Switzerland
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2008
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ETH Zurich
- Institute of Agricultural Sciences
Zürich, ZH, Switzerland
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