Characterisation of the first Australian isolate of Neospora caninum from cattle

OBJECTIVE: To isolate Neospora caninum from a congenitally infected calf. PROCEDURE: A calf was obtained from a N. caninum infected dam maintained in a dairy herd of Holstein-Friesian cattle located on the south coast of NSW near Nowra. The calf was euthanased and samples collected for serology and pathology. Samples of brain and spinal cord of the calf were homogenised and injected into immunocompromised mice in an attempt to recover protozoa by in vivo culture. Sequential passage of brain homogenate through IFNgammaPKO mice was performed and tissue culture flasks were inoculated with brain homogenate. Parasites were identified by electron microscopy and DNA sequencing. The antigen profile of the isolate was analysed using Western blotting. Pathogenicity was examined in BALB/c mice and transmission of the parasite during pregnancy was examined in Qs mice. RESULTS: The calf was seropositive for N. caninum and histopathological examination of sections of cerebrum identified lesions consistent with a very mild infection with N. caninum. The parasites isolated using tissue culture were identified as N. caninum, based on the sequence of the ribosomal DNA and electron microscopy. The antigen profile of the new isolate was similar to that of the NC-Liverpool isolate, but quite different from that of Toxoplasma gondii. In BALB/c mice inoculated with the new isolate, severe clinical signs developed in only three of ten infected mice, compared with six of ten mice infected with NC-Liverpool. Mild to moderate nonsuppurative encephalitis was observed in BALB/c mice infected with the new isolate, compared with mice infected with NC-Liverpool, that developed severe nonsuppurative encephalitis. Transplacental transmission of the isolate arising from an acute infection during pregnancy occurred in about 87% of pups. CONCLUSION: This is the first isolation of bovine Neospora caninum in Australia. This isolate, called NC-Nowra, appears to be a less virulent form and may prove to be a suitable candidate for vaccine development.     

Synchronous climate changes in antarctica and the north atlantic

Central Greenland ice cores provide evidence of abrupt changes in climate over the past 100,000 years. Many of these changes have also been identified in sedimentary and geochemical signatures in deep-sea sediment cores from the North Atlantic, confirming the link between millennial-scale climate variability and ocean thermohaline circulation. It is shown here that two of the most prominent North Atlantic events-the rapid warming that marks the end of the last glacial period and the Bolling/Allerod-Younger Dryas oscillation-are also recorded in an ice core from Taylor Dome, in the western Ross Sea sector of Antarctica. This result contrasts with evidence from ice cores in other regions of Antarctica, which show an asynchronous response between the Northern and Southern Hemispheres.     

The impact of malnutrition and other causes of losses of adult sheep in 12 flocks during drought

OBJECTIVE: To establish the range and cost of losses in Merino flocks in southern New South Wales during drought conditions by determining the cause of death, morbidity or wasting in adult sheep. DESIGN AND POPULATION: Pathological studies were performed on 392 dead or moribund adult sheep from 12 Ovine Johne's disease (OJD)-infected flocks during 2002 and a further 58 sheep culled due to wasting from one of these flocks in 2003. Flocks ranged between 3,500 and 20,000 sheep. METHOD: The most likely cause of death, morbidity or wasting was determined following consideration of the environment in which the animal was found, clinical and gross pathological findings, plus histopathology of tissues collected during necropsy. RESULTS: A most likely cause of death, morbidity or wasting was determined for 362 sheep in 2002 and 58 sheep in 2003. OJD contributed to the death of 250 sheep in 2002, and wasting of 48 sheep in 2003. Of the sheep that died or were euthanased due to other causes, malnutrition was a contributing factor in the death of 70 sheep (63%) in 2002 and 2 sheep (20%) in 2003. Losses were not evenly distributed across flocks, with 57% of mortalities caused by malnutrition in 2002 occurring in one flock. Malnutrition accounted for 18% of the annual cost of all deaths among adult sheep in 2002 with an average cost of $16,882 per farm. Losses not attributed to malnutrition included a range of infectious and non-infectious disorders. These included balanoposthitis, clostridial enterotoxaemia, cutaneous myiasis, endoparasitism, enteritis, intestinal adenocarcinoma, misadventure, peritonitis, periparturient death of ewes, photosensitisation, pneumonia, post-shearing stress and squamous cell carcinoma of the perineum. CONCLUSION: Almost one third of mortalities in OJD-infected flocks during drought were unrelated to OJD and could be reduced by improving nutritional and disease management practices. The importance of close supervision of the flock is highlighted so that early management intervention can be instituted, including the culling of cases of welfare concern.     

Molecular detection of microbes in nasal tissue of dogs with idiopathic lymphoplasmacytic rhinitis

Lymphoplasmacytic rhinitis (LPR) is a common histologic finding in dogs with chronic nasal disease; however, potential etiologies of this disorder have not been examined. We investigated the hypothesis that specific microbes contribute to clinical disease in dogs with LPR. Paraffin-embedded nasal biopsies were obtained from 19 dogs with LPR, 10 dogs with nasal neoplasia, and 10 dogs with nasal aspergillosis. Nucleic acids were extracted from paraffin blocks, and real-time quantitative polymerase chain reaction (PCR) was employed for detection of target genes for bacterial and fungal DNA, canine adenovirus 2 (CAV-2), parainfluenza virus 3 (PI-3), Chlamydial Chlamydophila spp., and Bartonella spp. Conventional PCR was used for detection of Mycoplasma spp. Statistical analysis was performed using the Mann-Whitney U-test for nonparametric data, and significance was set at P < 0.05. DNA or RNA for CAV-2, PI-3, Bartonella, Mycoplasma, and Chlamydophila was not detected in any nasal biopsy. DNA loads for bacterial DNA did not differ among disease groups. Detection of fungal DNA in nasal biopsies was highest in dogs with aspergillosis (P < 0.0001); however, nasal biopsies of LPR dogs also displayed higher fungal DNA levels than samples from dogs with nasal neoplasia (P = 0.016). Detection of high levels of fungal DNA in nasal biopsies of dogs with LPR suggests that fungal organisms may be causally associated with the inflammation observed, although the possibility of entrapment or accumulation of fungi in the nasal cavity due to chronic inflammation cannot be excluded. Further investigations are required to elucidate the underlying etiopathogenesis of LPR.     

Hydrops fetalis associated with pulmonary hypoplasia in Dexter calves

The occurrence of severe fetal dystocia due to hydrops fetalis associated with pulmonary aplasia in two male and pulmonary hypoplasia in one female Australian Dexter fetuses from two herds is described. Obstetrical intervention by caesarean section was required for delivery of the fetuses, with mortalities in one dam and the 3 calves. Clinical, pathological and genetic features are tabulated to assist in distinguishing pulmonary hypoplasia-associated hydrops fetalis from the more prevalent disorder of chondrodysplasia in Dexter cattle. Anasarca and complete absence or presence of only rudimentary lung tissue in a large thoracic cavity clearly distinguishes this entity from the lesions of Dexter chondrodysplasia that include severe micromelia and abundant lung tissue in a small thoracic cavity with shortened spine and rib cage. Pedigree information suggested that Dexter hydrops may be transmitted in an autosomal recessive manner.     

Design of Nonionic Surfactants for Supercritical Carbon Dioxide

Interfacially active block copolymer amphiphiles have been synthesized and their self-assembly into micelles in supercritical carbon dioxide (CO2) has been demonstrated with small-angle neutron scattering (SANS). These materials establish the design criteria for molecularly engineered surfactants that can stabilize and disperse otherwise insoluble matter into a CO2 continuous phase. Polystyrene-b-poly(1,1-dihydroperfluorooctyl acrylate) copolymers self-assembled into polydisperse core-shell-type micelles as a result of the disparate solubility characteristics of the different block segments in CO2. These nonionic surfactants for CO2 were shown by SANS to be capable of emulsifying up to 20 percent by weight of a CO2-insoluble hydrocarbon into CO2. This result demonstrates the efficacy of surfactant-modified CO2 in reducing the large volumes of organic and halogenated solvent waste streams released into our environment by solvent-intensive manufacturing and process industries.     

Lesions in sheep following administration of a vaccine of a Freund's complete adjuvant nature used in the control of ovine paratuberculosis

CASE HISTORIES: Occurrences of adverse reactions in seven sheep flocks in Australia following vaccination against paratuberculosis where veterinary attention was requested are reviewed. All cases occurred within the 3-year period following commencement of use of a vaccine of a Freund's complete adjuvant nature, at a time when approximately six million doses of vaccine had been administered.

CLINICAL FINDINGS: In the first case, 26/58 (45%) Merino sheep vaccinated as adults had palpable tissue reactions at or near the site of vaccination; enlarged prescapular lymph nodes were palpated in 17 (29%), and nine (16%) sheep had both palpable lesions at the site of vaccination and enlarged prescapular lymph nodes. The reactions included caseous nodules up to 5.5 cm in diameter. In the other cases, fistulating or granulomatous wounds were occasionally found at the recommended site of injection behind the ear, and myiasis was rare. Occurrences of inappropriate choice of injection site were recorded, including injection into the axilla of two Merino rams, and lesions in the tissues of the maxilla and nose of almost 50% of 350 Border Leicester lambs. Four outbreaks of progressive paralysis due to injection into cervical musculature were reported, described as ‘OJD staggers’ by producers.

DIAGNOSIS: Granulomatous cellulitis and lymphadenitis associated with oil droplets typical of ‘oil granulomata’. Injection of vaccine into the dorsal cervical area resulted in progressive paralysis due to myonecrosis and suspected granulomatous leptomeningitis.

CLINICAL RELEVANCE AND CONCLUSIONS: Although lesions at and near the site of injection are common, adverse reactions to vaccination were rare and included mortality from cervical spinal injection, production losses from injection in the maxilla or axilla or if myiasis resulted, and potential marketing losses if animals or carcasses are discounted as a result of the lesions. Risk factors for adverse reactions included inadequate restraint of sheep, breed of sheep, experience of the operator, poor injection technique, and inappropriate placement of vaccine. Increasing attention to the proper restraint of animals, restricting vaccination to the recommended site behind the ear, careful placement of the vaccine into subcutaneous tissue to avoid drainage of vaccine material into tissues such as the spinal cord, and post-vaccination supervision to address welfare concerns should adverse reactions occur are recommended.     

Thoracoscopic-assisted lung lobectomy in the dog: report of two cases

The benefits and application of thoracoscopy with selective ventilation, as an adjunct to thoracotomy, in facilitating pleural exploration and lung lobectomy in two dogs are presented. Similar thoracoscopic-assisted procedures are commonly used in human patients because there is better exposure and they are technically less demanding than thoracoscopy alone, while causing less postoperative morbidity than conventional thoracotomy. There are no previous reports of thoracoscopic-assisted surgery in the veterinary literature. In the cases described, thoracoscopic-assisted mini-thoracotomy was an effective, minimally-invasive approach for ipsilateral hemithorax exploration and lung lobectomy.