Coccidiosis in common wombats (Vombatus ursinus).

Eimeria arundeli is a widespread coccidian parasite of the common wombat (Vombatus ursinus), and has been considered to be nonpathogenic. We describe disease in two captive juvenile wombats ascribed to infection with E. arundeli. One animal had diarrhea, the second had mucoid soft feces and lost weight over several weeks prior to death. Masses of coccidial gametocytes in hypertrophic cells in the lamina propria distended villi, causing grossly visible raised pale thickened regions over extensive areas of the mucosa of the small intestine in both animals. Neutrophils infiltrated affected mucosa, and there was an inflammatory exudate into the intestinal lumen in case one. In case two, neutrophils infiltrated the lamina propria of villi focally, crypts were distended by necrotic debris, and epithelium on villi was extremely attenuated. No bacterial pathogens were isolated from lung and intestine in case one; case two was not cultured. Oocysts consistent with E. arundeli were present in large numbers in floatations of diarrheic feces in both cases.     

Clinical response of captive common wombats (Vombatus ursinus) infected with Sarcoptes scabiei var. wombati

Seven common wombats (Vombatus ursinus) were exposed and two of these were re-exposed to Sarcoptes scabiei var. wombati (Acari: Sarcoptidae). For wombats exposed for the first time, five exposed to 5,000 mites on their shoulder developed moderate to severe parakeratotic mange after 11 wk compared with two given 1,000 mites that developed mild clinical signs of mange after 11 wk. For re-exposed wombats, one of two given 5,000 mites developed mild parakeratotic mange and the other developed severe parakeratotic mange. Initial signs of mange were erythema followed by parakeratosis, alopecia, excoriation and fissuring of parakeratotic crust and skin. Erythema usually became apparent within 14 days after exposure (DAE) or within 24 hrs of re-exposure. Parakeratosis was visible 14-21 DAE and alopecia first occurred 35-77 DAE. Clinical signs increased in severity over time and lesions spread slowly from the site of exposure. Mangy wombats scratched excessively, lost weight, and exhibited a significant neutrophilia compared with control wombats. Treatment of mange with three injections of ivermectin, 300 micrograms/kg, 10 days apart led to complete resolution of clinical signs. However mites were not entirely eliminated until wombats received a second regime of treatment.     

Cellular response in the dermis of common wombats (Vombatus ursinus) infected with Sarcoptes scabiei var. wombati

The cellular response in the dermis of common wombats (Vombatus ursinus) with sarcoptic mange exhibited some typical aspects of an immune response to Sarcoptes scabiei. There was an induction phase for wombats experimentally infected with S. scabiei represented by absence of a dermal inflammatory infiltrate for at least 12 days after infection. T lymphocytes, plasma cells, mast cells, and neutrophils then entered the dermis, consistent with a type IV (delayed) hypersensitivity response. In free-living wombats with severe parakeratotic sarcoptic mange eosinophils were also present in the dermis suggesting that a type I (immediate) hypersensitivity response may develop after a type IV hypersensitivity response. Absence of plasma cells and B lymphocytes in free-living wombats with severe parakeratotic sarcoptic mange compared with their presence in wombats experimentally infected with S. scabiei suggested that some immune tolerance may develop with severe infections. A large proportion of cells in the dermal response were not identified but were possibly cells of connective tissue. The thickness of the epidermis increased within 4 days in response to S. scabiei infection. Some antibodies raised against human leucocyte antigens CD3, CD5, HLA-DP, DQ, DR, and CD79b cross-reacted with leucocyte antigens of common wombats and were used to identify cell types in inflammatory infiltrates using immunohistochemistry.     

Seroprevalence of Toxoplasma gondii in wild boars (Sus scrofa leucomystax) and wild sika deer (Cervus nippon) in Gunma Prefecture, Japan

The ingestion of undercooked meat from wild animals can be a source of Toxoplasma gondii infection in humans and other animals. In this study, we determined the seroprevalence of T. gondii infection in 175 wild boars (Sus scrofa leucomystax) and 107 wild sika deer (Cervus nippon) hunted in 2004–2007 in Gunma Prefecture, Japan, by using a commercial latex agglutination test (LAT). Antibodies (LAT, 1:64 or higher) to T. gondii were found in 6.3% of wild boars and 1.9% of sika deer. This is the first record of T. gondii infection in wild deer in Japan, and deer and wild boar meat should be cooked well before human consumption.     

Sarcoptes mange (Sarcoptes scabiei) increases diurnal activity of bare-nosed wombats (Vombatus ursinus) in an agricultural riparian environment

Sarcoptes mange is an important disease that affects the health, mobility and longevity of bare-nosed wombats (Vombatus ursinus) in Australia. We measured the activity patterns of wombats infected with varying levels of mange in an agricultural riparian environment using motion-sensing cameras. Over a 10 month period we observed a greater increase in nocturnal activity of mange-free wombats than those with mange on six or more body sections. The percentage of mange-infected wombats was greater during the day, but in the 6 h after midnight, wombats were detected with fewer mange-infected segments. Air temperature at the time of wombat detections was generally higher for individuals with mange than those without mange. Our results show that diurnal activity of wombats is likely to increase with higher levels of infection by sarcoptes mange. Increased diurnal activity is likely to present serious problems for the persistence of sustainable populations of wild wombats.     

Sarcoptes scabei var. wombati infection in the common wombat (Vombatus ursinus)

Sarcoptic mange has been identified as the most significant infectious disease affecting the common wombat (Vombatus ursinus). Biochemistry and haematology values for wild common wombats have not been published previously. A 35% of the wombat population were exhibiting clinical signs of the disease. Significant changes in blood haematology and biochemistry parameters were observed in affected animals. A seasonal variation in numbers of animals affected was demonstrated. Females appeared to be more commonly affected than males although the reason for this is not forthcoming.     

An investigation into the similarities and differences governing the cryopreservation success of koala (Phascolarctos cinereus: goldfuss) and common wombat (Vombatus ursinus: shaw) spermatozoa

The aim of this study was to determine the relative cryopreservation success of koala and wombat spermatozoa and to investigate reasons for their respective post-thaw survival by examining the sperm's response to a range of osmotic media and determining the presence and distribution of F-actin. An hypothesis was proposed that F-actin may be imparting a degree of structural inflexibility to the koala sperm plasma membrane; hence, exposure of spermatozoa to cytochalasin D (5 microM), a F-actin depolymerisation agent, should result in increased plasticisation of the membrane and greater tolerance of cell volume changes that typically occur during cryopreservation. In experiment 1, koala (n = 4) and wombat (n = 4) spermatozoa packaged in 0.25 mL straws were cryopreserved using two freezing rates (fast-3 cm above liquid N2 interface; slow-6 degrees C/min in a freezing chamber) and two glycerol concentrations (8 and 14% v/v) in a tris-citrate glucose buffer with 15% (v/v) egg yolk. Wombat spermatozoa showed better (P < 0.01) post-thaw survival (% motile, % intact plasma membranes, % decondensed sperm heads) than koala spermatozoa. When exposed to media of varying osmolality, koala spermatozoa were less tolerant (% intact plasma membrane) of hyper-osmotic conditions (920 and 1410 mOsmol/kg) than wombat spermatozoa. F-actin was localised using a monoclonal antibody but only found in the wombat sperm head. When koala and wombat spermatozoa were exposed to media of varying osmolality, cytochalasin D had no beneficial effect on sperm survival (% intact plasma membranes). This study has demonstrated that wombat spermatozoa are highly tolerant of cryopreservation when compared to koala sperm but that spermatozoa from both species show greatest post-thaw survival when frozen slowly in 14% glycerol. Koala sperm are also particularly susceptible to hyper-osmotic environments but lack of detectable F-actin in the koala spermatozoan suggests that poor cryopreservation success in this species is unlikely to be associated with F-actin induced plasma membrane inflexibility.     

A microscopic investigation of enamel in wombat (Vombatus ursinus)

Summary A study of the enamel of continuously growing Vombatus ursinus molars was carried out using the techniques of light microscopy, hardness testing, scanning electron microscopy and transmission electron microscopy. From the erupted end to within 8 mm of the growing end, mature enamel was observed and it was found that between comparable areas there were no significant ultrastructural differences in enamel; however, small (12nm diameter), loosely packed needle-like crystals characteristic of developing enamel were observed near the growing end. Mature enamel was found to consist of three optically-translucent regions interleaved with two opaque regions. Opaque enamel was softer than translucent enamel. The opacity and relative softness characteristic of two of the enamel regions was not related to prism pattern or orientation; it was, however, related to the presence of voids (28 nm diameter) in these regions.     

The influences of snow cover,vegetation and topography on the upper range limit of common wombats Vombatus ursinus in the subalpine zone,Australia

Aim In subalpine and alpine environments, range shifts of species to higher altitudes are predicted to occur in response to reductions in the snow cover from climate change. However, the distribution of key resources may constrain the range of animal populations and prevent any upward migration. This study examined the local resource constraints on the upper range limit of a large, native herbivore in Australia, the common wombat Vombatus ursinus. Location The subalpine zone of the Snowy Mountains, Australia. Methods Logistic regression analyses of snow and habitat predictors were conducted on the presence/absence of wombat signs recorded along an altitudinal gradient during winter and summer, using parametric and nonparametric methods. Results Wombats responded strongly to the altitudinal gradient, but snow cover alone did not fully explain their upper range limit. Wombat occurrence in the subalpine zone was influenced by local habitat features in combination with maximum snow depth. More rugged, high‐relief terrain was important to wombats in winter, allowing individuals access to a wider range of altitudes, snow depths and shelter sites. During summer, high soil bulk density was an important predictor of occurrence, and in both seasons, occurrence declined in response to a higher cover of burnt grass. Main conclusions These models demonstrate that local habitat factors play a role even where there are strong regulating environmental factors. For wombats, this may limit future range expansion into the alpine zone despite the potential for an increase in abundance at their present range limit. These findings show the need for local ecological studies to be conducted in parallel with broad scale climate modelling if we are to understand shifts in species distributions as the climate rapidly changes.     

Digestive tract morphology and digestion in the wombats (Marsupialia: Vombatidae)

Summary Wombats consume grasses and sedges which are often highly fibrous. The morphology of the digestive tract and the sequence of digestion were studied in two species of wombats from contrasting habitats: Vombatus ursinus from mesic habitats and Lasiorhinus latifrons from xeric regions. Studies were performed on wild wombats consuming their natural winter diets, and on captive wombats fed a high-fibre pelleted straw diet. Vombatus had a shorter digestive tract (9.2 vs 12.5 times body length) of greater capacity (wet contents 17.9 vs 13.7% body weight) than Lasiorhinus. The most capacious region of the digestive tract was the proximal colon (62–79% of contents). The proportional length and surface area of the proximal colon were greater in Vombatus, but those of the distal colon were greater in Lasiorhinus. These digestive morphologies may reflect adaptations for greater capacity and longer retention of digesta in Vombatus, but greater absorption and lower faecal water loss in Lasiorhinus. Apparent digestion along the digestive tract was estimated by reference to lignin. The proximal colon was the principal site of fibre and dry matter digestion, whereas nitrogen was mainly digested in the small intestine. Depot fats in captive wombats were highly unsaturated and reflected those in the diet. Therefore, lipids, proteins and soluble carbohydrates in the plant cell contents were digested and absorbed in the stomach and small intestine. Conversely, dietary fibre was probably retained and digested by microbial fermentation along the proximal colon.Abbreviations ADF acid detergent fibre - DM dry matter - NDF neutral detergent fibre - SD standard deviation     

Secretion of electrolytes,protein and urea by the mandibular gland of the common wombat (Vombatus ursinus)

Saliva was collected from the mandibular glands of anaesthetized common wombats (Vombatus ursinus) to ascertain maximal flow rates, salivary compostion and possible adaptations, particularly PO₄ ^3- secretion, to assist digestion. After temporary catheterization of the main duct through its oral opening, salivary secretion was evoked at flow rates ranging from 0.02±0.002 (±SEM) ml·min^-1 (0.7±0.07 l·min^-1·kg body weight^-1) to 0.4±0.05 ml·min^-1(14±1.9 l·min^-1·kg body weight^-1) by ipsilateral intracarotid infusion of acetylcholine. The [Na⁺] (15±5.1 to 58±8.6 mmol·l^-1) and [HCO₃ ^-] (35±1.9 to 60±1.9 mmol·l^-1) were positively correlated with salivary flow rate. The [K⁺] (58±5.2 to 30±2.4 mmol·l^-1), [Ca²⁺] (10.4±1.67 to 4.1±0.44 mmol·l^-1), [Mg²⁺] (0.94±0.137 to 0.17±0.032 mmol·l^-1), [Cl^-] (71±9.2 to 45±6.0 mmol·l^-1), [urea] (9.3±0.79 to 5.1±0.54 mmol·l^-1), H⁺ activity (29±1.6 to 17±1.6 nEq·l^-1) and amylase activity (251±57.4 to 92±23.3 kat·l^-1) were negatively correlated with flow. Both concentration and osmolality fell with increasing flow at the lower end of the flow range but osmolality always increased again by maximal flow whereas the relation between protein and flow was not consistent at the higher levels of flow and stimulation. Salivary [PO₄ ³⁺] was not correlated with flow and at 3–14% of the plasma concentration was extremely low. Thus, in contrast to its nearest relative, the koala (Phascolarctos cinereus), the wombat secretes little PO₄ ³⁺ presumably because it does not need high levels of PO₄ ³⁺ in its saliva to facilitate microbial digestion of plant fibre.Abbreviations bw body weight - ww wet weight     

Prevalence of Toxoplasma gondii in stray cats of Gyeonggi-do, Korea

Toxoplasma gondii is an obligate intracellular zoonotic protozoan with a worldwide distribution. It infects humans as well as a broad spectrum of vertebrate hosts. Cats and wild felidae play crucial roles in the epidemiology of toxoplasmosis. This study was performed to survey the prevalence of T. gondii infection among stray cats in the Gyeonggi-do, Republic of Korea. A total of 174 stray cat blood samples were collected from Gwacheon-si (n=20), Bucheon-si (82), and Yangju-si (72). Positive sera for T. gondii were identified in 14 samples (8.1%) exclusively via the latex agglutination test, 28 (16.1%) via ELISA, and 23 (13.2%) via PCR analysis. The overall infection rate of female stray cats (29.2%) presented as higher than that of male cats (24.0%). This study suggests that T. gondii is widespread in the stray cat population of Gyeonggi-do, Korea. It is urgently needed to control urban stray cat population and to reduce the risk of zoonotic transmission of toxoplasmosis to other animal hosts and humans.     

Seroprevalence of Toxoplasma gondii Infection in Police Dogs in Shenyang,Northeastern China

In recent years, worldwide surveys of Toxoplasma gondii infection in dogs have been reported. However, only limited surveys of T. gondii infection in police dogs have been available, including China. In the present study, we report the seroprevalence of T. gondii in police dogs in Shenyang, northeastern China. Sera from 291 police dogs were examined for T. gondii antibodies with the modified agglutination test (MAT), and 30.9% animals were tested seropositive. The results of the present study indicated a relatively high prevalence of T. gondii infection in police dogs in Shenyang, China.     

Isolation and chemical synthesis of a major, novel biliary bile acid in the common wombat (Vombatus ursinus): 15alpha-hydroxylithocholic acid

The major bile acids present in the gallbladder bile of the common Australian wombat (Vombatus ursinus) were isolated by preparative HPLC and identified by NMR as the taurine N-acylamidates of chenodeoxycholic acid (CDCA) and 15alpha-hydroxylithocholic acid (3alpha,15alpha-dihydroxy-5beta-cholan-24-oic acid). Taurine-conjugated CDCA constituted 78% of biliary bile acids, and (taurine-conjugated) 15alpha-hydroxylithocholic acid constituted 11%. Proof of structure of the latter compound was obtained by its synthesis from CDCA via a Delta14 intermediate. The synthesis of its C-15 epimer, 15beta-hydroxylithocholic acid (3alpha,15beta-dihydroxy-5beta-cholan-24-oic acid), is also reported. The taurine conjugate of 15alpha-hydroxylithocholic acid was synthesized and shown to have chromatographic and spectroscopic properties identical to those of the compound isolated from bile. It is likely that 15alpha-hydroxylithocholic acid is synthesized in the wombat hepatocyte by 15alpha-hydroxylation of lithocholic acid that was formed by bacterial 7alpha-dehydroxylation of CDCA in the distal intestine. Thus, the wombat appears to use 15alpha-hydroxylation as a novel detoxification mechanism for lithocholic acid.     

Serologic survey for Toxoplasma gondii and Neospora caninum in the common brushtail possum (Trichosurus vulpecula) from urban Sydney, Australia

The common brushtail possum (Trichosurus vulpecula) has well adapted to increasing urbanization, resulting in greater interaction with humans and their domestic pets. Wildlife species in urban areas face a higher risk of exposure to zoonotic pathogens and may be affected by parasites hosted by cats (Toxoplasma gondii) or dogs (Neospora caninum), yet it is unknown to what extent urban T. vulpecula are exposed to these parasites. Antibodies to T. gondii and N. caninum were assayed in sera of 142 adult possums from the city of Sydney, Australia. Using the modified agglutination test, antibodies to T. gondii were found in 9 (6.3%) of the 142 animals in titers of 1:25 (4), 1:50 (1), 1:100 (1), 1:800 (1), 1:3,200 (1), 1:6,400 (1), and 1:12,800 (1). Of some T. vulpecula multiple sera samples within a 2-yr frame could be collected, but seropositive animals in general were not recaptured after initial seroconversion. One possum had a high T. gondii titer on 2 consecutive bleedings, 14 mo apart, and seropositive possums appeared normal when captured. Sex seemed not to have an affect on antibody prevalence, but age and location may play a role. Antibodies to N. caninum were not detected in 1:25 dilution of sera in the N. caninum agglutination test, indicating that T. vulpecula may not have been exposed to this parasite. This is the first serological survey for T. gondii and N. caninum infections in urban T. vulpecula.     

The field energetics and water fluxes of free-living wombats (Marsupialia: Vombatidae)

Wombats are large, fossorial, herbivorous marsupials exhibiting physical and behavioural characteristics indicative of extreme energy conservation. Previous energetics studies have been limited to their basal metabolism under laboratory conditions; little is known of the energetics of free-living wombats. We measured seasonal field metabolic rates (FMR) and water fluxes in the three species of free-living wombat using the doubly labelled water technique, to further investigate the extent of energy conservation in the Vombatidae. Measurements were taken during the wet and dry annual extremes of their characteristically harsh environments, which corresponded to seasonal extremes of food and water availability. Seasonal FMRs for all wombat species were lower than that recorded for other marsupials and well below that predicted for herbivorous mammals. Dry-season FMR of Lasiorhinus kreftii was 40% of that predicted for a mammal. Wombats maintained energy balance during the poor season by reducing FMR to about half that of the good season. Water flux rates during the dry season for the arid-adapted Lasiorhinus are amongst the lowest recorded for mammals, being only 25% of that predicted for a similarly sized herbivorous mammal. These low water flux rates enable wombats in semi-arid areas to maintain water balance without drinking. Estimated food and nitrogen intake rates were also low. We conclude that the energetically frugal lifestyle of the Vombatidae is amongst the most extreme for mammals.