Distribution of life cycle stages of Sarcoptes scabiei var wombati and effects of severe mange on common wombats in Victoria.

Abstract

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.