C Wenker

University of Zurich, Zürich, Zurich, Switzerland

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Publications (16)20.7 Total impact

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    ABSTRACT: Pododermatitis is frequent in captive flamingos worldwide, but little is known about the associated histopathologic lesions. Involvement of a papillomavirus or herpesvirus has been suspected. Histopathologic evaluation and viral assessment of biopsies from 19 live and 10 dead captive greater flamingos were performed. Selected samples were further examined by transmission electron microscopy and immunohistochemistry. Feet from 10 dead free-ranging greater flamingos were also evaluated. The histologic appearance of lesions of flamingos of increasing age was interpreted as the progression of pododermatitis. Mild histologic lesions were seen in a 3-week-old flamingo chick with no macroscopic lesions, and these were characterized by Micrococcus-like bacteria in the stratum corneum associated with exocytosis of heterophils. The inflammation associated with these bacteria may lead to further histologic changes: irregular columnar proliferations, papillary squirting, and dyskeratosis. In more chronic lesions, hydropic degeneration of keratinocytes, epidermal hyperplasia, and dyskeratosis were seen at the epidermis, as well as proliferation of new blood vessels and increased intercellular matrix in the dermis. Papillomavirus DNA was not identified in any of the samples, while herpesvirus DNA was seen only in a few cases; therefore, these viruses were not thought to be the cause of the lesions. Poor skin health through suboptimal husbandry may weaken the epidermal barrier and predispose the skin to invasion of Micrococcus-like bacteria. Histologic lesions were identified in very young flamingos with no macroscopic lesions; this is likely to be an early stage lesion that may progress to macroscopic lesions. © The Author(s) 2015.
    Veterinary Pathology 01/2015; DOI:10.1177/0300985814568359 · 2.04 Impact Factor
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    ABSTRACT: The purpose of this study was to investigate the influence of feeding and UVB exposition on the occurrence and distribution patterns of vitamin D receptors (VDR) and calbindin D28k (Cb-D28k) in the gastrointestinal tract of veiled chameleons. Thus, 56 veiled chameleon hatchlings were divided into six treatment groups: UV (with UVB exposure); No (no supplements, no UVB exposure); CaAUV (with calcium (Ca), vitamin A supplementation, UVB exposure); CaA (with Ca, vitamin A supplementation); CaADUV (with Ca, vitamin A, vitamin D supplementation, UVB exposure); and CaAD (with Ca, vitamin A, vitamin D supplementation). Animals were reared under the suspected conditions for 6 months on locust-based diets. Tissue samples of stomach, duodenum, ileum and colon were taken, and semi-quantitative immunohistochemical methods (IHC) were performed to detect Cb-D28k and VDR. VDR immunoreactions were higher in the luminal epithelium of the duodenum than in that of the ileum. VDR immunoreactions in the luminal epithelium were higher at the base of the villi of the duodenum as compared to the tip. Cb-D28k immunoreactions were mainly observed in the luminal epithelium of the duodenum. The two groups treated with all dietary supplements (CaADUV, CaAD) exhibited a higher Cb-D28k immunoreaction as those with no supplements and UVB exposure only. No immunoreaction for both proteins could be detected in the stomach. This study suggests that the duodenum plays an important role in the active transcellular absorption of Ca in veiled chameleons as shown by the immunohistochemical detection of VDR and Cb-D28k. Expression of Cb-D28k, in particular, appears to be regulated by dietary supplementation of vitamin D and vitamin A. VDRs, however, tended to be upregulated when animals were not supplemented with Ca, vitamin D and vitamin A. This may be due to the decreased Ca concentrations which caused vitamin D activation in the skin without any supplementation, but UVB exposure.
    J Anim Physiol a Anim Nutr 05/2014; 98(6). DOI:10.1111/jpn.12206 · 1.32 Impact Factor
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    ABSTRACT: Pododermatitis is a worldwide problem in captive flamingos. Studies in domestic poultry showed that nutrition is a possible influencing factor for pododermatitis. Vitamin A and E, copper and zinc levels were analysed in two different diets (diet 1 = in-house mix and diet 2 = commercial diet) and in plasma of captive greater flamingos fed these diets and compared to those of free-ranging greater flamingos. Results were analysed with respect to type and severity of foot lesions of the individuals from the different groups. Juvenile and subadult/adult captive flamingos on diet 1 showed various types and severities of foot lesions, whereas no foot lesions were found at the time of blood sampling in juvenile captive flamingos on diet 2. Juvenile captive flamingos on diet 1 had significantly lower plasma zinc levels than juvenile captive flamingos on diet 2 and juvenile free-ranging flamingos; data were also lower than reference ranges for flamingos, poultry and cranes. There were no significant differences in plasma vitamin A, vitamin E, copper or zinc levels between animals with different types of foot lesions or with different severity scores. Shortly after the change to diet 2 (fed to juvenile captive flamingos that did not show any foot lesion), the flooring of the outdoor water pools was covered with fine granular sand. Because both factors (nutrition and flooring) were changed during the same evaluation period, it cannot be concluded which factor contributed in what extent to the reduction of foot lesions. While it is assumed that low plasma zinc levels identified in the group of juvenile captive flamingos on diet 1 were not directly responsible for foot lesions observed in these animals, they may have played a role in altering the skin integrity of the feet and predisposing them to pododermatitis.
    J Anim Physiol a Anim Nutr 03/2014; 98(6). DOI:10.1111/jpn.12184 · 1.32 Impact Factor
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    ABSTRACT: Pododermatitis is a worldwide health and animal welfare problem in captive flamingos (Phoenicopteridae). Since sub-optimal substrate or flooring has been described as a factor in the development of pododermatitis in poultry and raptors, it is also suspected to play a role in flamingo foot health. Small groups of flamingos were separated from the main group in an indoor enclosure with artificial grass carpet and, in earlier years, concrete flooring, with additional fine granular sand in the water basin for the study year. Feet were evaluated before and after the separation. Judged subjectively, foot lesions had shown a general increase in the indoor enclosure in earlier years. In contrast, lesion severity and prevalence, scored in accordance with a standardised protocol, decreased when fine granular sand was provided. Since flamingos were observed mostly standing on sand and as this represented the major differentiating factor between years, it is concluded that fine granular sand is a favourable substrate to maintain, and one that may even lead to an improvement in flamingo foot health.
    Animal welfare (South Mimms, England) 02/2014; 23(1). DOI:10.7120/09627286.23.1.057 · 1.23 Impact Factor
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    ABSTRACT: Twenty great apes (six orangutans, eight chimpanzees and six gorillas) were anaesthetised prior to being transported for undergoing diagnostic and interventional procedures. Anaesthesia was induced with a combination of medetomidine and ketamine administered intramuscularly through a dart syringe. The onset of anaesthesia varied among apes: the mean (±sd) time from darting to recumbency was 12.13 (±1.9), 18.5 (±8.7) and 22.2 (±9.2) minutes in chimpanzees, orangutans and gorillas, respectively. The depth of anaesthesia was sufficient to allow safe removal of the animals from the enclosure, intravenous catheter placement and manipulation; however, the anaesthetic effect was short-acting (20 (±7) minutes in orangutans, 16 (±14) in gorillas, and 10 (±4) minutes in chimpanzees, respectively) and isoflurane administration was necessary in the majority of the apes to prolong the duration of anaesthesia, especially when lengthier procedures were performed. The sedative effect of medetomidine was reversed at the end of each procedure with atipamezole, and recovery was smooth and uneventful for all animals.
    08/2012; 171(8):196. DOI:10.1136/vr.100761
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    ABSTRACT: Although metabolic bone disease (MBD) is a very common disease in reptiles kept as pets, empirical data on the calcium (Ca) metabolism of reptiles are still scarce. We used the opportunity of a large-scale experimental study on growth and clinical manifestations of MBD in captive veiled chameleons (Chamaeleo calyptratus) to measure the apparent dry matter (DM) and Ca digestibility in 19 animals (6-49 g), receiving locust nymphs (Locusta migratoria) of two size classes (0.05 and 0.5 g) with or without supplementation of Ca, vitamin A and cholecalciferol (Group A: Ca 0.04-0.09%DM; Group B: Ca 0.47-0.84%DM). Dry matter digestibility was significantly lower for animals receiving smaller-sized prey. A regression analysis of dietary Ca vs. digestible Ca content revealed a complete 'true' digestibility of Ca for the range of investigated diets, which might indicate that requirements for this mineral were not yet exceeded by the diets used (so that a reduction in Ca absorption would be induced). Options of higher dietary Ca provision, and reactions of chameleons to such diets, should be further investigated.
    J Anim Physiol a Anim Nutr 06/2011; 96(5):778-82. DOI:10.1111/j.1439-0396.2011.01170.x · 1.32 Impact Factor
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    ABSTRACT: Three cases of fatal septicaemia due to Plesiomonas shigelloides and one due to Edwardsiella tarda were diagnosed in newborn penguins from the Basle Zoo, Switzerland from 2003 to 2007. The affected penguins were of two different species (king penguin, Aptenodytes patagonicus, and African penguin, Spheniscus demersus) and between 2 and 10 days old at the time of death. The causative agents, E. tarda and P. shigelloides are ubiquitous bacteria which are reported to be present in the normal intestinal flora of wild and captive aquatic animals, including penguins. Their occurrence and infectious potential is discussed.
    SAT Schweizer Archiv für Tierheilkunde 03/2011; 153(3):117-21. DOI:10.1024/0036-7281/a000165 · 0.38 Impact Factor
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    ABSTRACT: Little information is available in English on the keeping and breeding of the rarest equid species, the Critically Endangered Somali wild ass Equus africanus somalicus, in captivity. The husbandry experience gained by Basel Zoo over three decades of keeping this species is summarized with particular emphasis on management, nutrition and health.
    International Zoo Yearbook 12/2008; 43(1):198 - 211. DOI:10.1111/j.1748-1090.2008.00072.x
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    ABSTRACT: Scuticociliatosis is a disease of fish induced by ciliated parasites of the genus Scuticociliatida. It has been described in sea horses (Hippocampus sp.), flounders (Paralichthys olivaceus), and turbots (Scophthalmus maximus). Here we present a case study of a population of sea dragons chronically infected with scuticociliates identified as Philasterides dicentrarchi by histopathology and PCR. Beginning in 2004, over a period of 19 months, 10 sea dragons (Phycodurus eques and Phyllopteryx taeniolatus) were found dead in an aquarium of the Zoological Garden Basle, Switzerland. Clinically, the animals showed only faint symptoms of disease over a short period of time. At necropsy, macroscopic lesions were confined to the skin with multiple, often hemorrhagic, ulcerations. Histologically, epidermal ulcers were associated with necrosis and inflammation of the underlying dermis and musculature. Numerous ciliates, with a morphology consistent with scuticociliates, were present in these lesions. In several animals these ciliates had invaded blood vessels and were detected in gills and internal organs including kidney, thyroid gland, and central nervous system (CNS). In these organs, mild degenerative lesions and inflammatory reactions were evident. The ciliates were identified as Philasterides dicentrarchi based on small-subunit ribosomal RNA (SSUrRNA) gene sequences obtained by polymerase chain reaction (PCR) on DNA extracted from paraffin-embedded tissue sections. Our report shows that scuticociliate infections of sea dragons can develop into a systemic infection and that both species of sea dragons can be affected.
    Veterinary Pathology 08/2008; 45(4):546-50. DOI:10.1354/vp.45-4-546 · 2.04 Impact Factor
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    ABSTRACT: Primary renal tumors are rare neoplasms in nonhuman primates. This report describes a mixed epithelial and stromal tumor of the kidney (MESTK) in a 14.5-year-old female ringtail lemur. The well-demarcated, solid, and cystic mass was located in the pelvis of the left kidney and consisted histologically of both epithelial and mesenchymal components. The mesenchymal cells were arranged in fascicles around cysts lined by a well-differentiated epithelium. Neither the mesenchymal nor the epithelial parts showed significant nuclear atypia or mitotic figures. To our knowledge, only 1 similar case, classified as adenoleiomyofibromatous hamartoma, has been reported in a ringtail lemur. In humans this tumor affects predominantly perimenopausal women and can express estrogen and progesterone receptors. However, neither estrogen nor progesterone receptors could be identified by immunohistochemistry in the tumor of the present ringtail lemur. Therefore, a hormonal mechanism could not be demonstrated in this case.
    Veterinary Pathology 04/2007; 44(2):243-6. DOI:10.1354/vp.44-2-243 · 2.04 Impact Factor
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    ABSTRACT: The decision to perform euthanasia in geriatric zoo mammals is usually a highly complex procedure involving ethical, medical, emotional and sometimes political factors. However, subsequent necropsies show that the pathological changes of organs and/or the musculoskeletal system are often already advanced. Therefore, we hypothesise that euthanasia is often delayed to the detriment of the animal's welfare. The purpose of this study was to facilitate and establish an initial, objective, decision-making framework for the euthanasia of geriatric zoo mammals. A scoring-system to assess the physical condition and quality of life in ageing zoo mammals is presented, based on retrospective and prospective investigation of 70 geriatric zoo mammals in five European zoos. Medical records and necropsy reports were studied in retrospective cases. Symptoms were monitored and recorded in prospective cases. Radiographic investigations under general anesthesia or at necropsy were performed additionally. A significant association between symptoms and pathological findings revealed that 36.9% (n = 24/65) of examined animals (n = 41/65) had pathological alterations to the musculoskeletal system and 26.2% (n = 17/65) suffered from neoplasia. Based on the individual reports, 28 veterinarians from different fields of veterinary medicine concluded that these animals had mild to severe pain, discomfort and a significantly reduced quality of life, thus strongly reducing welfare. The proposed scoring system includes all of these factors and offers a simple and reliable tool to support decision-making for euthanasia in geriatric zoo mammals.
    Animal welfare (South Mimms, England) 01/2007; 16(3). · 1.23 Impact Factor
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    ABSTRACT: The first case of spongiform encephalopathy in a zebu (Bos indicus) was identified in a zoo in Switzerland. Although histopathologic and immunohistochemical analyses of the central nervous system indicated a diagnosis of bovine spongiform encephalopathy (BSE), molecular typing showed some features different from those of BSE in cattle (B. taurus).
    Emerging infectious diseases 01/2007; 12(12):1950-3. DOI:10.3201/eid1212.060750 · 7.33 Impact Factor
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    European Association of Zoo and Wildlife Veterinarians, Budapest, Hungary; 05/2006
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    ABSTRACT: Natural infections with the lancet fluke (Dicrocoelium dendriticum) were detected in a group of seven diseased or dead/euthanized South American Camelids (five Llamas, two Alpacas) from Switzerland and Southern Germany. Clinical findings in almost all the animals revealed an acute decline of general condition followed by recumbency, decreased body temperature and a varying degree of anaemia. Concurrently, all animals showed an average to poor nutritional status. All liver enzyme activities analysed in serum biochemistry conformed to the reference values and therefore offered no diagnostic clues for this disease. Necropsy however, disclosed major alterations in the liver in the form of cirrhosis, abscesses, granulomas, and a massive infestation with D. dendriticum. The coprological investigations performed at the outset of the examinations revealed eggs of the lancet fluke in only two animals. This suggests that clinical findings alone permit at best only a provisional diagnosis. Repeated coprologic follow-ups showed that the presence of eggs of D. dendriticum can be diagnosed accurately and that clinical signs appear with an excretion rate above 1000 eggs per gram faeces (EpG). In these cases, praziquantel in a single dose of 50 mg/kg per os was given. This treatment was well tolerated and achieved a quite acceptable 90% reduction of eggs in the faeces.
    Tierärztliche Praxis. Ausgabe G, Grosstiere/Nutztiere 12/1998; 26(6):355-61. · 0.47 Impact Factor
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    ABSTRACT: In 2007, two different events for teaching principles in zoo and wildlife medicine and for introducing veterinary students to scientific work were organized, the “Zoo Research Camp 2007” at the Al Wabra Wildlife Preservation, Qatar, and the “First EAZWV Summer School” at Basle Zoo. Apart from support from the hosting facilities, events were organized by the Clinic of Zoo Animals, Exotic Pets and Wildlife of the Vetsuisse Faculty. The two events differed in concept – with more emphasis on research and data evaluation at the ZRC, and on lectures at the Summer School. Both events had in common that a limited group of students convened at a place different from their usual location, in a zoo setting, which was considered the key to their motivation and the success of the events. Here, we describe the two concepts in detail, also explaining the required commitments made by, and the benefits for, the participating hosts or organisations. We hope that other zoos will be open to host similar events in the future.
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