EQUINE HERPESVIRUSES: Type 3 as an Abortigenic Agent

The inoculation of equine herpesvirus type 3 (EHV3) strain 65/61 into the amniotic cavity of a mare 6-7 months pregnant resulted in abortion 11 days later. Following abortion typical lesions of coital exanthema were not observed in the genital tract of the mare, nor was EHV3 isolated from her. Serological evidence, however, indicated that the mare was infected with EHV3 following inoculation. Grossly the foetal disease was characterised by placentitis, focal ulcerative dermatitis, focal necrosis of the lungs and a striking diptheritic gastritis. Histological findings were interstitial pneumonia, diffuse hepatitis, generalised myositis, extensive vascular necrosis and degeneration of a range of epithelial cells. EHV3 was isolated from the placenta and placental fluids, stomach fluid, pooled thoracic and abdominal fluid, skin, lung, spleen and small intestine of the foetus.     

CLINICAL SIGNS, RADIOLOGY AND TISSUE LEAD DISTRIBUTION OF DOGS ADMINISTERED A MIXTURE OF LEAD CHLORIDE, LEAD BROMIDE AND LEAD SULPHATE

SUMMARY Eight-month-old dogs maintained on a high-fat-low-calcium diet were administered a mixture of lead chloride, lead bromide and lead sulphate for prolonged periods at 4 different dose levels. Dogs on high levels of lead showed marked weight loss and gastrointestinal symptoms followed by death. Two dogs on low lead levels developed neurological signs. Radiological investigations showed radiopaque particles in 27 per cent of abdominal radiographs and 'lead lines' in the distal radius of 3 dogs. Highest tissue lead levels were found in bones followed by liver and kidney, brain and spinal cord.     

Evaluation of two seminal collection regimens for mature Holstein bulls

Twenty mature Holstein bulls (3 to 10 yr old) were used to test the effect of two semen collection regimens on spermatozoal output, post-thaw percentage spermatozoal motility, and time needed to make the collections/week. For both regimens, six ejaculates/wk were collected using either three ejaculates/d, 2 d/wk, or two ejaculates/d, 3 d/wk. A three-period switchback experimental design was used. Each collection period for which measurements were taken was 3 wk and was preceded by a 2 wk period of acclimation. The total number of spermatozoa harvested per week was not significantly different (P greater than .05): 33.2 X 10(9) when the bulls were collected two ejaculates 3 d/wk, compared with 33.9 X 10(9) three ejaculates 2 d/wk. Post-thaw progressive spermatozoal motility was 50.3 and 52.1% (P greater than .05), respectively. The average time per week to collect each bull was 73.6 and 83.7 min (P less than .05), respectively.     

Thoracic high-resolution computed tomography in the diagnosis of metastatic carcinoma

Three dogs were presented for investigation of recurrent pyrexia of unknown origin, chronic vomiting and respiratory distress, respectively. One dog was markedly underweight and the other two were cachexic. Physical examination and initial diagnostic tests failed to establish the underlying cause of the presenting signs. Thoracic radiographs were within normal limits for the age of the dog. In each case there was a high index of suspicion for an occult neoplastic process in view of the profound unexplained weight loss present. High-resolution computed tomography (HRCT) of the thorax was performed. The lung fields were divided into three zones for analysis and a novel classification scheme was used to describe the HRCT findings in each zone. Postmortem examination and histopathology confirmed the presence of an infiltrating metastatic carcinoma in all three cases. The HRCT changes correlated closely with the pathological findings. The authors conclude that HRCT of the lung should be considered for pulmonary metastatic screening in the dog and introduce a classification system for HRCT findings, based on terminology used in human medicine.     

Unidentified Plasmodium species in Australian black swans (Cygnus atratus) hatched and raised in North America

A pair of Australian black swans (Cygnus atratus) with origins in Wakefield, Virginia, USA, was admitted to the quarantine area at the Baltimore Zoo for general health assessments before housing in the collections. During the quarantine period, no clinical signs of disease were manifest; however, upon examination of a blood smear, intraerythrocytic parasites were detected and initially determined to be Haemoproteus species. Diagnostic polymerase chain reaction (PCR) and sequencing results, however, indicated that the parasites were within the genus Plasmodium. Subclinical infections with Plasmodium species in birds may affect collection management, and transmission from refractory hosts to susceptible hosts should be considered when multispecies exhibits are used. In addition, changes in the dynamics of host-vector-parasite interactions might have significant impacts on wild or domesticated populations of birds.     

Modeling the Concentration of Aluminum in Surface Waters

Although the increased mobilization of aluminum from soils to surface waters is widely recognized as one of the most important ecological effects of acidic deposition, lumped-parameter mathematical models of acidification response typically overestimate the change in Al concentration under changing deposition by a considerable margin. The assumption of equilibrium with gibbsite (Al(OH)₃) in the MAGIC model and other models of acid-base chemistry is shown to be inconsistent with measured values for a large variety of lake and stream databases. A modified algorithm for predicting Al concentration, based on empirical relationships evident in field data, provided superior estimates of changes in Al concentration in three long-term monitoring data sets and under experimental conditions at two experimental watershed manipulation sites.