Although mortality in 3 groups of 15 green tree frogs Litoria caerulea exposed to 3 isolates of Batrachochytrium dendrobatidis was 100%, time to death varied with isolate, highlighting the importance of strain and/or passage history in pathogenicity studies and possibly in the epidemiology of chytridiomycosis. A standard naming scheme for isolates of B. dendrobatidis is proposed. KEY WORDS: Batrachochytrium dendrobatidis · Amphibian chytrid fungus · Chytridiomycosis · Amphibian · Strain variation · Virulence · Litoria caerulea Resale or republication not permitted without written consent of the publisherDis Aquat Org 68: [47][48][49][50] 2005 ment along with automated water flow was highly effective in preventing cross-contamination as evidenced by the lack of infection in the tubs of control frogs that were placed randomly among infected tubs. Room temperature varied between 16 and 20°C.Isolates of Batrachochytrium dendrobatidis were obtained from sick frogs by culturing on tryptone/ gelatin hydrolysate/lactose (TGhL) agar with antibiotics (Longcore et al. 1999). The 3 strains were (1) strain 98 1469/10 cultured from a captive-bred metamorph of Limnodynastes dumerilii from the ARC (17 mo old culture), (2) strain 99 1385/12 cultured from a wild adult of Litoria caerulea from Rockhampton, Queensland (9 mo old culture), and (3) strain 00 545 cultured from a captive metamorph of Litoria lesueuri from the ARC that had been collected as a tadpole from Gibbo River, north-eastern Victoria (1.5 mo old culture). Cultures were maintained in TGhL broth at 4°C and were passaged every 2 to 3 mo.Zoospores were collected from 4 d old agar cultures, prepared from actively growing 1 wk old broth cultures at 22°C. Zoospores were harvested by flooding plates with distilled water for 5 min, then removing water by pipette. The concentration of zoospores was counted in a counting chamber. The zoospore suspension was stored in plastic tissue culture flasks and kept below 20°C until frogs were infected within 6 h. The motility of zoospores was confirmed by microscopic examination immediately before infections were conducted.Litoria caerulea were exposed individually in the dark to 50 000 zoospores in 5 ml distilled water in 45 mm × 50 mm yellow top specimen containers (Labserv) for 24 h. Fifteen frogs were exposed to strains 98 1469/10 and 00 545 and 14 to strain 99 1385/12. Fifteen control frogs were also treated this way, except that they were exposed to water washed off a clean agar plate.Chytridiomycosis was diagnosed at Day 19 by histology of toe clips, and at death by examination of shedding epidermal sheets (Berger et al. 1999) from all frogs and by histology on 5 individuals per group. The experiment was terminated when the last infected frog died. Frogs were euthanized when clinical signs of disease became obvious by bathing in 0.2% MS 222 (tricaine methanesulfonate) (Ruth Consolidated Industries). Lethargy and a delayed righting reflex were considered to indicate that death was certain. As there is usually a shor...

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Seven female and three male common wombats (Vombatus ursinus) collected from forested areas of Victoria (Australia) over a 10 mo period, 10 April 1997 to 22 February 1998 had at least 30% of their skin affected by severe hyperkeratotic sarcoptic mange. Mangy wombats were grazing during the day, could be readily approached, were in poor body condition, and lacked subcutaneous fat. The anterolateral surface of the body was most heavily parasitised with Sarcoptes scabiei var wombati followed by the posterolateral surface, the dorsal region between the ears, the ears, ventral abdomen, medial aspect of the legs, axillary and inguinal areas, and the dorsal midline. Larvae were the most prevalent life-cycle stage followed by eggs, nymphs, females, and males. Mite numbers and the severity of clinical signs, namely thickness of scale crust and the degree of alopecia, were correlated and were symmetrical on each side of the body. Fissuring of crust and skin only occurred when scale crust was present. Bacterial infections occurred in three of 10 wombats within lymph nodes or the pleural cavity. Lymphoid depletion did not occur in lymph nodes or spleens and prescapular lymph nodes contained a greater amount of nuclear debris in germinal centres than non-mangy wombats. Seven wombats had fatty change in their livers. Gonads of mature wombats were not active or had minimal activity. Significant histopathological changes were not seen in the gastrointestinal tract, kidney, brain, myocardium, spleen, thyroid, reproductive tract, and gonads. Hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, and concentrations of hemoglobin, lymphocytes, calcium, glucose, creatinine, total solids, total protein, albumin determined both colormetrically and electrophoretically, and globulins were significantly lower and concentrations of neutrophils, monocytes, phosphorus, urea, glutamate dehydrogenase, aspartate aminotransferase and creatine kinase were significantly higher in mangy versus captive wombats. Concentrations of erythrocytes, mean corpuscular hemoglobin, leucocytes, band neutrophils, eosinophils, nucleated erythrocytes, sodium, potassium, chloride, total bilirubin, alkaline phosphatase, and gamma glutamyltransferase for mangy wombats were not significantly different from that reported for captive wombats. Hematological and pathological changes in mangy wombats were consistent with anemia, inflammation, and changes seen with starvation.

Sarcoptic mange occurs in common wombat populations throughout the range of the common wombat including Tasmania and Flinders Island. While mange epizootics are sporadic, they have the potential to threaten the long-term survival of small, remnant populations.

Free-living common wombats (Vombatus ursinus) living at high densities on pastoral land (1.9 wombats ha–1) had most of their burrows (83%) confined to a 20-m-wide strip of remnant riparian vegetation adjacent to pasture (24 burrows ha–1). The ratio of wombats to 'active' burrows (being used by wombats) was 1.0. Wombats shared burrows extensively, with a mean of 3.1 ± 0.3 (s.e.), range 2–9 wombats using each burrow (n = 37). The majority (70%) of occupied burrows contained several wombats independent of age, sex and stage of reproduction. On average, wombats used the same burrow for 3.8 consecutive nights before changing to another. Home ranges of wombats overlapped completely. Adult males had larger home ranges than females with young (7.3 ± 0.6, 6.1–8.3 ha, n = 3 versus 3.8 ± 0.5, 2.4–5.0 ha, n = 4, respectively). Distances travelled and the area used each night by wombats decreased in late winter and spring, when food was more abundant. Breeding occurred throughout the year but there was a cluster of births in summer. Lactation was associated with weight loss in females of several kilograms. Usually larger (30 kg) males that shared burrows or used burrows near (<300 m) to the burrows used by a female sired her young; however, occasionally wombats that used widely separated burrows (>700 m) bred. Adult males had a greater head length to weight ratio than adult females. Adult males generally emerged from their burrows shortly after dusk and 30 min before adult females. Ectoparasites such as ticks, mites, fleas and lice were common but the mite Sarcoptes scabiei was not found nor were there signs of sarcoptic mange in the population.

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Abstract. Chytridiomycosis is the worst disease to affect vertebrate biodiversity on record. In Australia, it is thought to have caused the extinction of four frog species, and it threatens the survival of at least 10 more. We report the current distribution and host range of this invasive disease in Australia, which is essential knowledge for conservation management. We envisage that the data be used in a global and national context for predictive modeling, meta-analyses, and risk assessment. Our continent-wide data set comprises 821 sites in Australia and includes 10 183 records from .80 contributors spanning collection dates from 1956 to 2007. Sick and dead frogs from the field and apparently healthy frogs from museum collections were tested opportunistically for the presence of Batrachochytrium dendrobatidis, the fungal pathogen causing chytridiomycosis, and apparently healthy frogs and tadpoles found during surveys were tested purposively. The diagnostic tests used were histology of skin samples and quantitative PCR of skin swabs.

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 g/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.