Clinical signs and duration of cyanide toxicosis delivered by the M-44 ejector in wild dogs

Sodium cyanide poison is potentially a more humane method to control wild dogs than sodium fluoroacetate (1080) poison. This study quantified the clinical signs and duration of cyanide toxicosis delivered by the M-44 ejector. The device delivered a nominal 0.88 g of sodium cyanide, which caused the animal to loose the menace reflex in a mean of 43 s, and the animal was assumed to have undergone cerebral hypoxia after the last visible breath. The mean time to cerebral hypoxia was 156 s for a vertical pull and 434 s for a side pull. The difference was possibly because some cyanide may be lost in a side pull. There were three distinct phases of cyanide toxicosis: the initial phase was characterised by head shaking, panting and salivation; the immobilisation phase by incontinence, ataxia and loss of the righting reflex; and the cerebral hypoxia phase by a tetanic seizure. Clinical signs that were exhibited in more than one phase of cyanide toxicosis included retching, agonal breathing, vocalisation, vomiting, altered levels of ocular reflex, leg paddling, tonic muscular spasms, respiratory distress and muscle fasciculations of the muzzle.

Early recovery signs of an Australian grassland following the management of Parthenium hysterophorus L

Parthenium weed (Parthenium hysterophorus L.) is believed to reduce the above- and below-ground plant species diversity and the above-ground productivity in several ecosystems. We quantified the impact of this invasive weed upon species diversity in an Australian grassland and assessed the resulting shifts in plant community composition following management using two traditional approaches. A baseline plant community survey, prior to management, showed that the above-ground community was dominated by P. hysterophorus, stoloniferous grasses, with a further high frequency of species from Malvaceae, Chenopodiaceae and Amaranthaceae. In heavily invaded areas, P. hysterophorus abundance and biomass was found to negatively correlate with species diversity and native species abundance. Digitaria didactyla Willd. was present in high abundance when P. hysterophorus was not, with these two species, contributing most to the dissimilarity seen between areas. The application of selective broad leaf weed herbicides significantly reduced P. hysterophorus biomass under ungrazed conditions, but this management did not yet result in an increase in species diversity. In the above-ground community, P. hysterophorus was partly replaced by the introduced grass species Cynodon dactylon L. (Pers.) 1 year after management began, increasing the above-ground forage biomass production, while D. didactyla replaced P. hysterophorus in the below-ground community. This improvement in forage availability continued to strengthen over the time of the study resulting in a total increase of 80% after 2 years in the ungrazed treatment, demonstrating the stress that grazing was imposing upon this grassland-based agro-ecosystem and showing that it is necessary to remove grazing to obtain the best results from the chemical management approach.

Confirmation of Elsey virus infection in a Queensland horse with mild neurologic signs

In 2011, a 2-year-old horse in northern Queensland, Australia, was reported to have developed mild neurologic signs, and a blood sample was submitted for laboratory investigation. Virus isolation was performed using the blood sample, and an orbivirus was isolated. This was confirmed to be a strain of Elsey virus (ELSV) after transmission electron microscopy and nucleotide sequencing. The nucleotide sequence was compared with those in GenBank, and had 100% identity with ELSV previously reported from the Northern Territory, Australia. ELSV is taxonomically closely related to Peruvian horse sickness virus.

Toxoplasmosis in Indo-Pacific humpbacked dolphins (Sousa chinensis) from Queensland

Objective: To describe the clinical signs, gross pathology, serology, bacteriology, histopathology, electron microscopy and immunohistochemistry findings associated with toxoplasmosis in four Indo-Pacific humpbacked dolphins (Sousa chinensis) that stranded in Queensland in 2000 and 2001. Design: Clinical assessment, gross necropsy, and laboratory examinations. Procedure: Necropsies were performed on four S chinensis to determine cause of death. Laboratory tests including serology, bacteriology, histopathology and transmission electron microscopy were done on the four dolphins. lmmunohistochemistry was done on the brain, heart, liver, lung, spleen and adrenal gland from various dolphins to detect Toxoplasma gondii antigens. Results: Necropsies showed all of four S chinensis that stranded in Queensland in 2000 and 2001 had evidence of predatory shark attack and three were extremely emaciated. Histopathological examinations showed all four dolphins had toxoplasmosis with tissue cysts resembling T gondii in the brain. Tachyzoite stages of T gondii were detected in the lungs, heart, liver, spleen and adrenal gland, variously of all four dolphins. Electron microscopy studies and immunohistochemistry confirmed the tissues cysts were those of Tgondii. All four dolphins also had intercurrent disease including pneumonia, three had peritonitis and one had pancreatitis. Conclusion: Four S chinensis necropsied in Queensland in 2000 and 2001 were found to be infected with toxoplasmosis. It is uncertain how these dolphins became infected and further studies are needed to determine how S chinensis acquire toxoplasmosis. All four dolphins stranded after periods of heavy rainfall, and coastal freshwater runoff may be a risk factor for T gondii infection in S chinensis. This disease should be of concern to wildlife managers since S chinensis is a rare species and its numbers appear to be declining.

Presence of Nicotinamide Adenine Dinucleotide–Independent Haemophilus paragallinarum in Mexico

Two isolates of Haemophilus paragallinarum were obtained from a layer chicken in Mexico. The isolates were confirmed as H. paragallinarum by polymerase chain reaction and conventional biochemical identification. The isolates were nicotinamide adenine dinucleotide (NAD) independent—growing on blood agar without the need of a nurse colony as well as on a complex medium that lacked both NAD and chicken serum. Both isolates were pathogenic, causing the typical clinical signs of infectious coryza in susceptible chickens. One isolate was Page serovar B/Kume serovar B-1 and the other isolate was Page serovar C/Kume serovar C-2. The isolates were associated with a field outbreak that involved an egg drop of 20% over a 3 wk period and a doubling of weekly mortality (from 0.1% to 0.2%). This is the first report of NAD-independent H. paragallinarum outside South Africa and is the first time that NADindependent H. paragallinarum of serovar B has been reported. Abbreviations: NAD ¼ nicotinamide adenine dinucleotide; NAM ¼ nicotinamide; PCR ¼ polymerase chain reaction; TM ¼ complete growth medium without chicken serum or nicotinamide adenine dinucleotide; TM/SN ¼ complete growth medium that contains both chicken serum and nicotinamide adenine dinucleotide

Virulence of the Nine Serovar Reference Strains of Haemophilus paragallinarum

The virulence of the reference strains of the nine currently recognized Kume serovars of Haemophilus paragallinarum was investigated. The capacity of the H. paragallinarum strains to cause the typical clinical signs of upper respiratory tract disease associated with infectious coryza in unvaccinated, nasal-challenged chickens was assessed. Differences in virulence were assessed by means of a standardized scoring system for clinical signs. All nine strains were pathogenic to chickens, producing typical clinical signs of infectious coryza. The highest clinical signs score was obtained for serovar C-1 (1.72), while the lowest clinical signs score was obtained for serovar C-4 (0.32). Our results indicate that virulence differences exist among the serovars of H. paragallinarum.

Zearalenone intoxication of pigs

Mycotoxicosis due to ingestion of zearalenone was detected on 2 pig farms on the Atherton Tableland in northern Queensland. In one herd of 200 pigs, this resulted from feeding maize which had been stored with a high moisture content. In the other herd of 1400 pigs, it resulted from feeding sorghum grain which was rain affected before harvest. Concentrations of zearalenone in the feeds ranged up to 8 mg/kg. Most prepubertal gilts in the herds displayed enlarged teats and signs of oestrus such as having red, swollen vulvas. In several cases both rectal and vaginal prolapses occurred. On one of the farms, 25 pigs died as a direct result of prolapses. Autopsy of a 3-monthold gilt revealed apparently enlarged ovaries and uterine horns. Sows and boars seemed to be unaffected. Four gilts failed to conceive following mating during the period of zearalenone ingestion, but apart from this and the deaths from prolapses, production of the herds appeared ti be unaffected.

Australian Bat Lyssavirus Infection in a Captive Juvenile Black Flying Fox

The newly emerging Australian bat lyssavirus causes rabies like disease in bats and humans. A captive juvenile black flying fox exhibited progressive neurologic signs, including sudden aggression, vocalization, dysphagia, and paresis over 9 days and then died. At necropsy, lyssavirus infection was diagnosed by fluorescent antibody test, immunoperoxidase staining, polymerase chain reaction, and virus isolation. Eight human contacts received postexposure vaccination.

Standardising bull breeding soundness evaluations and reporting in Australia

There is substantial variation in bull breeding soundness evaluation procedures and reports in Australia; the situation is compounded by difficulties in interpretation and the validity of many reports. In an effort to overcome this, the scientific literature was reviewed [Fordyce G. In: Fordyce G, editor. Bull fertility: selection and management in Australia. Eight Mile Plains, Australia: Australian Cattle Vets; 2002] and the needs of stakeholders were considered in preparing a manual, Evaluating and Reporting Bull Fertility [Entwistle KW, Fordyce G. Evaluating and reporting bull fertility. Eight Mile Plains, Australia: Australian Cattle Vets; 2003.] that outlined standards for assessing and reporting bull breeding soundness. A new recording and reporting system, called Bull Reporter, is based on standards from this manual and groups bull fertility traits into five summary categories: Scrotum, Physical, Crush-side Semen, Sperm Morphology, and Serving. The client will generally select which categories they wish to have included in the evaluation to suit their specific purposes. While there is adequate room for comments, the veterinarian is not required to make an overall judgment of whether the bull has normal capacity to sire calves under natural mating management, but ensures the standards for each selected category are met. Professional, standardised, easy-to-read reports are produced either electronically [Entwistle KW, Fordyce G. Evaluating and reporting bull fertility. Eight Mile Plains, Australia: Australian Cattle Vets; 2003.] or manually. A bull owner or their agent signs the certificate to affirm that bulls have not undergone procedures to rectify faults which may have otherwise caused them to fail the standards. An accreditation system for assessing sperm morphology was established because of its demonstrated relationship with pregnancy rates and because of the difficulties in achieving consistent and accurate assessments among laboratories. It is considered that Bull Reporter is applicable to beef and dairy bulls across all levels of management, genotypes and environments throughout Australia, with substantial potential for application elsewhere in the world.

The vaccination-challenge trial: the gold standard test to evaluate the protective efficacy of infectious coryza vaccines

Infectious coryza is an upper respiratory tract disease of chickens with the major impact occurring in multi-age flocks. We investigated the relationship between the level of antibodies, as detected by a haemagglutination-inhibition (HI) assay, in infectious coryza-vaccinated chickens and the protection against challenge in those chickens. In one experiment, chickens given a single dose of either of two infectious coryza vaccines lacked a detectable HI response to vaccination but showed significant levels of protection 11 weeks after vaccination. In contrast, in chickens given two doses of an infectious coryza vaccine and challenged 3 weeks after the second vaccine dose, there was a strong serological response with 36/40 birds having a HI titre of 1/20 or greater. In this trial there was an apparent relationship between titre and subsequent protection, with none of the 32 chickens with a titre of 1/40 or 1/80 showing any clinical signs and only one of the same group yielding the challenge organism on culture. In contrast, three of the four vaccinated chickens with a HI titre less than 1/5 developed the typical clinical signs of coryza and yielded the challenge organism on culture. Overall, our results suggest that HI titres cannot be regarded as a definitive predictor of vaccine efficacy. We suggest that the vaccination-challenge trial is the gold standard for the evaluation of the immune response to infectious coryza vaccines.

Pimelea trichostachya poisoning (St George disease) in horses

A dense population of Pimelea trichostachya plants (Family Thymelaeaceae) in pasture poisoned a horse herd in southern inland Queensland in October-November 2005. Plant density was 2 to 45 g wet weight/m2 (mean 16 g/m2) from 5 to 69 plants/m2 (mean 38 plants/m2) representing 3 to 20% (mean 9%) of the volume of pasture on offer. Ten of 35 mares, fillies and geldings were affected. Clinical signs were loss of body weight, profound lethargy, serous nasal discharge, severe watery diarrhoea and subcutaneous oedema of the intermandibular space, chest and ventral midline. Pathological findings were anaemia, leucocytopenia, hypoproteinaemia, dilatation of the right ventricle of the heart, dilated hepatic portal veins and periportal hepatic sinusoids (peliosis hepatis), alimentary mucosal hyperaemia and oedema of mesenteric lymph nodes. Cattle grazing the same pasture were affected by Pimelea poisoning simultaneously. Removal of the horses to Pimelea-free pasture initiated recovery. The one other incident of this syndrome, previously only recognised in cattle in Australia, occurred in horses, in South Australia in 2002, with access to a dense Pimelea simplex population.

Fluorescence in situ hybridization analysis of hindgut bacteria associated with the development of equine laminitis

In the article 'Fluorescence in situ hybridization analysis of hindgut bacteria associated with the development of equine laminitis' (Milinovich et al., 2007), it is found that with reference to Horse 1, the histological signs of laminitis were first observed at 12 h post-oligofructose administration, and not 30 h as was indicated in the Results section under the subheading 'Induction of Laminitis' and in Fig. 1.

Bovine mucopolysaccharidosis type IIIB

Mucopolysaccharidosis IIIB, an autosomal recessive lysosomal storage disorder of heparan sulfate caused by mutations in the α-N-acetylglucosaminidase (NAGLU) gene, was recently discovered in cattle. Clinical signs include progressive ataxia, stumbling gait, swaying and difficulty in balance and walking. These clinical signs are usually first observed at approximately 2 years of age and then develop progressively over the lifespan of the animals. Affected bulls were found to be homozygous for the missense mutation E452K (c.1354G>A). The availability of mutational analysis permits screening for the NAGLU mutation to eradicate this mutation from the cattle breeding population.

Clinical and pathological findings associated with congenital hypovitaminosis A in extensively grazed beef cattle

To determine the cause of exceptionally high mortality (41.4%) in perinatal calves on a beef cattle property 50 km south-west of Julia Creek in north-western Queensland. Investigations were based on clinical assessment of affected calves and laboratory analysis of pre- and postmortem specimens taken from 12 calves aged from 6 to 36 h of age. Associations between gross and histopathological findings and biochemical analyses conducted on serum and tissue samples were examined in relation to clinical observations. Clinical signs varied, but commonly included mild to severe ataxia, difficulty finding a teat and sucking, blindness (partial or complete, as judged by avoidance of obstacles) and depression with prominent drooping of the head. Gross and histopathological findings included herniation of the cerebellar vermis through the foramen magnum, squamous metaplasia of interlobular ducts in the parotid salivary glands and Wallerian degeneration of the optic nerves. Biochemical analysis of serum and liver samples available from four of the calves revealed low or undetectable levels of both vitamin A and vitamin E. Although vitamin E is known to have a sparing effect on vitamin A, the role (if any) played by deficiency of this vitamin was uncertain. The combination of clinical signs, postmortem findings, histopathological features and biochemical findings indicate that gestational vitamin A deficiency was highly likely to have been an important contributor to perinatal calf mortalities in this herd.

Australian Bat Lyssavirus

In Chapter 1, the literature relating to rabies virus and the rabies like lyssaviruses is reviewed. In Chapter 2, data are presented from 1170 diagnostic submissions for ABLV testing by fluorescent antibody test (Centocor FAT). All 27 non-bat submissions were ABLV-negative. Of 1143 bat accessions 74 (16%) were ABLV-positive, including 69 of 974 (7.1%) flying foxes (Pteropus spp.), 5 of 7 (71.4%) Saccolaimus flaviventris (Yellow-bellied sheathtail bats), none of 151 other microchiropteran bats, and none of 11 unidentified bats. Statistical analysis of data from 868 wild Black, Grey-headed, Little Red and Spectacled flying foxes (Pteropus alecto, P. poliocephalus, P. scapulatus, and P. conspicillatus) indicated that three factors; species, health status and age were associated with significant (p< 0.001) differences in the proportion of ABLV-positive bats. Other factors including sex, whether the bat bit a person or animal, region, year, and season submitted, were not associated with ABLV. Case data for 74 ABLV-positive bats, including the circumstances in which they were found and clinical signs, is presented. In Chapter 3, the aetiological diagnosis was investigated for 100 consecutive flying fox submissions with neurological signs. ABLV (32%), spinal and head injuries (29%), and neuro-angiostrongylosis (18%) accounted for most neurological syndromes in flying foxes. No evidence of lead poisoning was found in unwell (n=16) or healthy flying foxes (n=50). No diagnosis was reached for 16 cases, all of which were negative for ABLV by TaqMan PCR. The molecular diversity of ABLV was examined in Chapter 4 by sequencing 36 bases of the leader sequence, the entire N gene, and start of the P gene of 28 isolates from pteropid bats and 3 isolates from Yellow-bellied sheathtail (YBST) bats. Phylogenetic analysis indicated all ABLV isolates clustered together as a discrete group within the Lyssavirus genera closely related to rabies virus and European bat lyssavirus-2 isolates. The ABLV lineage consisted of two variants; one (ybst-ABLV) consisted of isolates only from YBST bats, the other (pteropid-ABLV) was common to Black, Grey-headed and Little Red flying foxes. No associations were found between the sequences and either the geographical location or year found, or individual flying fox species. In Chapter 5, 15 inocula prepared from the brains or salivary glands of naturally-infected bats were evaluated by intracerebral (IC) and footpad (FP) inoculation of Quackenbush mice in order to select and characterize a highly virulent inoculum for further use in bats (Inoculum 5). In Chapter 6, nine Grey-headed flying foxes were inoculated with 105.2 to 105.5 MICED50 of Inoculum 5 divided into four sites, left footpad, pectoral muscle, temporal muscle and muzzle. Another bat was inoculated with half this dose divided into the footpad and pectoral muscle only. Seven of 10 bats developed clinical disease of 1 to 4 days duration between PI-days 10 and 19 and were shown to be ABL-positive by FAT, HAM immunoperoxidase staining, virus isolation in mice, and TaqMan PCR. Five of the seven bats displayed overt aggression, one died during a seizure, and one showed intractable agitation, pacing, tremors, and ataxia. Viral antigen was demonstrated throughout the central and peripheral nervous systems and in the epithelial cells of the submandibular salivary glands (n=4). All affected bats had mild to moderate non-suppurative meningoencephalitis and severe ganglioneuritis. No ABLV was detected in three bats that remained well until the end of the experiment on day 82. One survivor developed a strong but transient antibody response. In Chapter 7, the relative virulence of inocula prepared from the brains and salivary glands of experimentally infected flying foxes was evaluated in mice by IC and FP inoculation and TaqMan assay. The effects in mice were correlated to the TaqMan CT value and indicated a crude association between virulence and CT value that has potential application in the selection of inocula. In Chapter 8, 36 Black and Grey-headed flying foxes were vaccinated with one (day 0) or two (+ day 28) doses of Nobivac rabies vaccine and co-vaccinated with keyhole limpet haemocyanin (KLH). All bats responded to the Nobivac vaccine with a rabies-RFFIT titer > 0.5 IU/mL that is nominally indicative of protective immunity. Plasma from bats with rabies titres >2 IU/mL had cross-neutralising ABLV titres >1:154. A specifically developed ELISA detected a strong but transient response to KLH.