Concurrent avian malaria and avipox virus infection in translocated South Island saddlebacks (Philesturnus carunculatus carunculatus)

CASE HISTORY

Outbreaks of mortality in South Island saddlebacks (Philesturnus carunculatus carunculatus) that had been translocated to two offshore islands in the Marlborough Sounds of New Zealand were investigated during the summers of 2002 and 2007. Both outbreaks were associated with a severe decrease in numbers of saddlebacks of up to 60% of approximately 200 birds.

CLINICAL AND PATHOLOGICAL FINDINGS

Many of the surviving birds were in poor condition, and had skin lesions on the legs and head. Necropsy showed pale liver and lungs, and a swollen spleen. Histopathology revealed schizonts resembling Plasmodium spp. within the cytoplasm of many hepatocytes and splenic histiocytes. The skin lesions consisted of epithelial proliferations containing numerous Bollinger bodies typical of avipox virus (APV) infection. Two different APV were isolated, using PCR, from two different birds exhibiting skin lesions. Each isolate had 100% sequence homology with APV members from either Clade A or Clade B. In addition, PCR analysis revealed that the Plasmodium elongatum present in infected birds belonged to a strain that was endemic in the population of North Island saddlebacks (Philesturnus carunculatus rufusater).

DIAGNOSIS

Concurrent infections with Plasmodium spp. haemoparasites and APV were identified as the likely cause of death in the birds examined.

CONCLUSIONS AND CLINICAL RELEVANCE

Although the Plasmodium spp. identified is thought to be endemic to saddlebacks in New Zealand, the affected birds were likely to be immunocompromised by concurrent APV infection or through lack of genetic diversity. Both the introduced mosquito Culex quinquefasicatus and the native mosquito Culex pervigilans are likely vectors for both these diseases, and the provision of water supplies less favourable to mosquito-breeding is recommended.

Severe complication after administration of formalin for treatment of progressive ethmoidal hematoma in a horse

Formalin was injected into an ethmoidal hematoma in an 18-year-old Arabian gelding. Abnormal neurologic signs were observed within minutes of the injection. The horse did not respond favorably to medical treatment of the neurologic signs and was euthanatized. Postmortem examination revealed erosion and necrosis of the ventral cribriform plate, which appeared to have allowed the injected formalin to reach the rostral portion of the frontal lobe of the brain. Endoscopy and radiography had been performed prior to euthanasia, but neither delineated the cribriform lesion. Before treating large progressive ethmoidal hematomas with formalin, it may be beneficial to perform computed tomography to assess the extent of damage caused by the lesion.

Far-ultraviolet spectrographs: the impact of holographic grating design

One of NASA's major scientific initiatives in astrophysics, the Far Ultraviolet Spectroscopic Explorer, is an orbiting observatory designed to perform high-resolution spectroscopy of stellar objects between 910 and 1150 Å. To achieve the 100 cm(2) of effective area required to observe faint quasars, the mission has adopted an unconventional design that couples grazing-incidence Wolter optics and an aberration-corrected Rowland circle spectrograph. The projected cost of the satellite has, however, become very high, driven in large part by the cost of the grazing optics and the side effects of compensating for their relatively poor performance. The logic that leads to the current design is reanalyzed, and it is argued that because of the technical developments of the last 7 years, grazing incidence is no longer the most attractive alternative. In particular, the application of aberration-corrected, spherical substrate, holographic gratings now greatly simplifies the design and thereby reduces the cost. A new is presented that substantially outperforms the old and that is easier to fabricate.

Multifocal subacute necrotizing encephalomyelopathy in Simmental calves

In 24 cases of multifocal necrotizing encephalopathy (MNE) in Simmental and Simmental-cross cattle, clinical features varied, consisting of mild rear limb ataxia, caudal paresis, and, less often, sudden death. Bilateral and symmetric malacic lesions were present in the brain stem (olivary nucleus) of all affected calves. Foci of malacia affecting thoracic spinal cord and additional brain stem sites were common. Neuronal cell bodies and hypertrophied capillaries were present within malacic foci. Rarefaction of neuropil, progressing to complete parenchymal loss, characterized advanced lesions. Pathologic features were similar to those of Leigh syndrome in humans, and a similar defect in aerobic metabolism is hypothesized. Occurrence of the syndrome within 1 breed over a wide geographic area suggests that hereditary factors contribute to development of MNE.

Skeletal muscle of cattle affected with progressive degenerative myeloencephalopathy

Skeletal muscle from multiple sites of 6 cattle afflicted with progressive degenerative myeloencephalopathy was analyzed by transmission electron microscopy and compared with skeletal muscle taken from 2 clinically normal cattle (controls) similarly studied. Major changes in the affected muscle included abnormal myoneural junctions with redundant junctional folds that were abnormally long and branching, and occasionally separated from the synaptic site; multiple vacuoles of variable size clustered in subsarcolemmal positions and in rows between myofibrils; bizarre mitochondria with thin connecting stalks, large electron-dense bodies, and abnormal cristae; and cone-shaped projections of the sarcolemma. These findings indicate that myopathy is part of the progressive degenerative myeloencephalopathy phenotype.

Upper motor neurone and descending tract pathology in bovine spinal muscular atrophy

The extent of neuropathology in a recently reported disease of Brown Swiss cattle, spinal muscular atrophy (SMA), was investigated with light and electron microscopy. Many regions of the central nervous system were sampled from 10 SMA-affected and three normal Brown Swiss calves. In addition to extensive necrosis of lower motor neurones there was extensive upper motor neurone degeneration and descending tract pathology. Since these abnormalities are also hallmarks of amyotrophic lateral sclerosis (ALS), SMA may be an animal model for that disease. There was also considerable vacuolar degeneration, which is a feature of the wobbler mouse and murine type C RNA virus-induced paralytic disease models of ALS.

Electron microscopic studies of bovine progressive degenerative myeloencephalopathy in brown Swiss cattle

Selected peripheral nerves from animals affected with Bovine Progressive Degenerative Myeloencephalopathy (BPDME) were examined by transmission electron microscopy. Changes in axons were both degenerative and reactive in nature and included axonal swelling in conjunction with accumulation of altered organelles and various forms of vesicles. Affected axoplasm was often vacuolated and shrunken, with loss of microtubules and microfilaments and separation of the axoplasmic membrane from the myelin sheath. Segmental disorganization of the normal lamellar pattern of myelin sheaths was observed. Affected myelin sheaths exhibited intramyelinic vacuoles or myelin bubbles often in association with concurrent axonal changes. Schwann cells occasionally contained swellen and vacuolated mitochondria and membrane-bound vesicles. Axonal and myelin changes were considered similar, if not identical, to those described in the central nervous system of affected animals reported in the literature. Collectively, the changes described in the axons and myelin sheaths of the peripheral nerves studied were considered to be compatible with the "dying back" process described in various distal axonopathies. A metabolic defect in the enzyme systems associated with axonal transport was postulated to explain these peripheral nerve lesions.

Histochemical and morphometric studies of peripheral muscle in bovine progressive degenerative myeloencephalopathy of brown Swiss cattle

Histochemical and morphometric analysis of selected skeletal muscles was performed on 14 pure bred, Brown Swiss cattle. Nine cattle were clinically affected with bovine progressive degenerative myeloencephalopathy (BPDME) while five served as controls. Statistically significant trend differences were not observed for the parameters of mean cross sectional area, and mean fiber type percentages for types, I, IIA, and IIB fibers between affected and control test groups. In general, patterns of hypertrophy or atrophy, fiber type grouping, fiber type predominance, or fiber cross sectional profile alteration were not observed in the muscles examined from affected cattle. The findings suggest that BPDME, or weaver syndrome, is not a muscular dystrophy and that muscle pathology is not a primary part of the syndrome nor would muscle pathology be expected to contribute significantly to the clinical signs of the disease.

The Spectrum of Comet Austin from 910 to 1180 Å

A spectrum of comet Austin (1988 c(1)) has been obtained from 910 to 1180 A. Three bright emission lines were detected, including a forbidden oxygen line (1128 A), which are attributable to radiative pumping of neutral oxygen by solar Lyman beta. The relative strengths of the observed features should prove to be a useful diagnostic of the physical conditions and radiation fields in cometary comae. In addition, the absence of strong spectral features from highly volatile species such as He, Ar, or N(2) can be used to place constraints on the thermal environment under which the comet was formed and has been processed.

Reduction of spiral ganglion neurons in the aging canine with hearing loss

The middle and inner ears of 16 dogs, from 1.5 to 17 years of age, with differing degrees of suspected hearing loss were examined. Auditory function was assessed subjectively, and electrophysiologically by recording brainstem auditory-evoked responses (BAER) to click stimuli. Ossicular chains and stapediovestibular articulations were evaluated macroscopically and by light microscopy for evidence of bony ankylosis; no abnormalities were found. A determination of spiral ganglion packing density revealed a loss of spiral ganglion cells in all areas of the cochlea in dogs of the deaf group and in the upper and lower basal region of dogs from the hearing impaired group. The largest losses of spiral ganglion cells in the deaf group were located in the upper and lower basal region. The deaf group's density was reduced to 44% (upper basal) 15% (lower basal) of the normal hearing group. The largest spiral ganglion cell loss for dogs in the hearing impaired group occurred in the lower basal region where the density was reduced to 40% of the normal hearing group. These morphological findings in the aging canine are consistent with a peripheral nerve hearing loss.

X-ray optics: a technique for high resolution imaging

Both scattering and figure errors in grazing incidence optics are larger in the plane of incidence than out-of-plane by a factor equal to 1/sintheta, where theta is the graze angle. When the full annular aperture of a grazing incidence telescope is stopped down, the point spread function becomes highly elliptical with a width as much as sintheta times narrower than the full image. In practice this means that improvements in resolution of up to 100 times can be achieved, and effective resolution can approach the diffraction limit. Laboratory data demonstrating the effect are presented.

Echelle spectrographs at grazing incidence

It is shown that by using the conical diffraction mount existing echelle gratings can be used at grazing incidence to achieve high spectral resolution in the extreme UV and soft x rays. Design considerations for grazing incidence echelle spectrographs are examined, and two sample designs are discussed. The first, for use in the extreme UV has a primary mirror and an entrance slit to the spectrograph. The system has resolution of 10(4), operates at any wavelength longward of 100 A, and covers 30% of the spectrum at a single setting. The x-ray spectrograph uses objective gratings to obtain spectral resolution of 2.8 x 10(4) over any factor of 2 in wavelength. It operates to wavelengths as short as 4 A.

Extreme ultraviolet reflection efficiencies of diamond-turned aluminum, polished nickel, and evaporated gold surfaces

We report measurements of reflection efficiencies from 44 A to 1048 A for samples of polished nickel, diamond-turned aluminum, and various thicknesses of gold evaporated onto the nickel and aluminum samples. The reflection efficiencies are presented for grazing angles from 5 degrees to 75 degrees . For wavelengths longer than ~100 A, the gold-coated nickel surface provides the highest efficiencies, while for wavelengths shorter than 100 A the nickel is superior. The optimal thickness of gold is found to be ~500 A. The performance of grazing incidence optics using nickel and aluminum substrates for an evaporated gold surface is discussed.