Disseminated histoplasmosis in a Bengal tiger (Panthera tigris)

Disseminated infection with Histoplasma capsulatum was diagnosed in a 7-yr-old female Bengal tiger (Panthera tigris). Clinical signs were nonspecific with the exception of brief periods of tachypnea for 5 days prior to death. H. capsulatum organisms were found in the lungs, tracheobronchial lymph nodes, and liver. Diagnosis was confirmed by tracheal wash, urine H. capsulatum enzyme immunoassay, and necropsy results. This report represents the first published account of disseminated histoplasmosis in a tiger.     

Diagnostic testing patterns of natural Mycobacterium paratuberculosis infection in pygmy goats

Thirteen pygmy goats (Capra hircus) from a herd naturally infected with Mycobacterium avium ss. paratuberculosis (MPTB) were monitored with 4 diagnostic assays for 2 to 15 mo. Cellular and humoral immune responses to the infection were assessed with assays of gamma interferon (IFNγ), serum antibody [enzyme-linked immunosorbent assay (ELISA) and agar gel diffusion (AGID)], and radiometric fecal culture. Microscopic examination and radiometric culture of tissue from 12 sites were performed at necropsy. Goats were considered infected if MPTB was isolated from any tissue sample collected at necropsy. Mycobacterial isolates were confirmed as MPTB with an IS900 polymerase chain reaction assay. Ten goats whose antemortem tests indicated infection carried heavy organism burdens at necropsy, both within and beyond the gastrointestinal system. False-negative ELISA, AGID, and/or culture results were obtained in 5 of the 10 confirmed cases during the study period. In 3 goats with sporadic fecal shedding of MPTB or detectable IFNγ response, or both, no abnormalities were detected at necropsy and no MPTB was isolated from the tissue samples; the antemortem fecal-culture and IFNγ results were thus considered false-positive. Diagnosticians should be alert to the possibility of both false-positive and false-negative test results for Johne's disease in goats. False-positive fecal-culture results may occur when a high prevalence of infection exists in the herd and the premises are likely to be heavily contaminated. The diverse antemortem testing patterns seen in these goats underscore the importance of using varied diagnostic assays serially or in parallel to increase the likelihood of identifying all infected goats.     

Investigations of an enteric infection of cockatoos caused by an enterovirus-like agent

An enteric infection in cockatoos associated with a 30 nm diameter enterovirus-like agent seen in faeces and intestinal epithelial cells is described. The disease is characterised by intractable, profuse, mucoid diarrhoea, weight loss, dehydration and death. Lesions in the intestine consist of villous atrophy, villous fusion, enterocyte hyperplasia and, in some cases, chronic inflammation. Affected birds so far examined have concurrent psittacine beak and feather disease.     

Septin-mediated plant cell invasion by the rice blast fungus, Magnaporthe oryzae

To cause rice blast disease, the fungus Magnaporthe oryzae develops a pressurized dome-shaped cell called an appressorium, which physically ruptures the leaf cuticle to gain entry to plant tissue. Here, we report that a toroidal F-actin network assembles in the appressorium by means of four septin guanosine triphosphatases, which polymerize into a dynamic, hetero-oligomeric ring. Septins scaffold F-actin, via the ezrin-radixin-moesin protein Tea1, and phosphatidylinositide interactions at the appressorium plasma membrane. The septin ring assembles in a Cdc42- and Chm1-dependent manner and forms a diffusion barrier to localize the inverse-bin-amphiphysin-RVS-domain protein Rvs167 and the Wiskott-Aldrich syndrome protein Las17 at the point of penetration. Septins thereby provide the cortical rigidity and membrane curvature necessary for protrusion of a rigid penetration peg to breach the leaf surface.     

The impact of highly concentrated Mo and Cu dietary supplements,fed as a bolus,on the efficacy of chelated versus inorganic Cu in cattle on a low-Cu diet

AIM: To compare the efficacy of chelated versus inorganic forms of dietary Cu supplements, fed as a bolus, when challenged by a daily bolus of dietary Mo in cattle on a low-Cu diet.

METHODS: Forty non-lactating, Friesian dairy cows of adequate Cu status were assigned to four groups and fed a basal diet of baled silage containing 5.3 mg Cu and 0.4 mg Mo/kg DM. The experimental design was a factorial of two chemical forms of supplemental Cu and two levels of Mo intake, provided as pelleted grain supplements made from crushed barley/molasses plus Cu and Mo. The supplements contained 140 mg Cu/kg as Cu sulphate pentahydrate (CS), 140 mg Cu/kg as Cu glycinate (CG), CS plus 38 mg Mo/kg as sodium molybdate (CS+Mo), or CG plus 38 mg Mo/kg (CG+Mo). Commencing on Day 0, supplements were fed once daily (offered 1–1.2 kg/cow) and were completely consumed within 5–10 minutes, which constitutes a bolus type of administration. Liver samples were collected by biopsy at Days ?24, 13, 41 or 47, and 69 for Cu determinations.

RESULTS: The diets fed to the Cu+Mo groups were roughly equivalent to 25 mg Cu and 5.7 mg Mo/kg DM. Mean initial concentration of Cu in liver for all groups was 516 (SE 54) μmol Cu/kg fresh tissue. In cows supplemented with CS and CG, the final (Day 69) concentrations increased (p<0.01) to 939 (SE 166) and 853 (SE 163) μmol Cu/kg, respectively. These values were not different (p=0.72). For groups CS+Mo and CG+Mo, the final concentrations of 535 (SE 122) and 453 (SE 102) μmol Cu/kg were not different from initial values or from each other (p>0.25). The rate of accumulation of Cu in liver following bolus Cu and Mo intake was highly variable but was not affected by initial concentration of Cu in liver (p>0.9) or by the form of Cu (p>0.6). Mean rates of accumulation of Cu in liver were 4.0 (SD 3.8) and 0.65 (SD 2.0) μmol Cu/kg fresh tissue/day for the Cu-only treatments and the Cu+Mo treatments, respectively.

CONCLUSIONS: When fed together as a bolus, high Mo intake negated the effect of supplemental Cu but it did not reduce liver Cu stores. There was no difference in the reaction of dietary Mo with chelated Cu (as glycinate) versus inorganic Cu (as sulphate) dietary supplements.     

Evaluation of von Willebrand Factor During Pregnancy,Lactation and Oestrous Cycle in Bitches Affected and Unaffected by von Willebrand Disease

Plasmatic concentrations of von Willebrand Factor (vWF) increase during pregnancy in humans and dogs; however the mechanism of such increase is still not well defined. The aims of this study were: (i) to evaluate changes in vWF concentration during pregnancy and during the subsequent oestrous cycle in bitches affected and unaffected by von Willebrand Disease (vWD); (ii) to correlate the vWF levels and cortisol levels in both groups. Seven vWD affected (GI) and nine unaffected (GII) bitches were used. The animals were assessed during pregnancy, parturition, lactation and non‐gestational oestrous cycle in 11 moments (Pregnancy 1, Pregnancy 2, Parturition, Lactation 1, Lactation 2, Lactation 3, Anestrus, Proestrus, Oestrus, Diestrus 1, and Diestrus 2). The following tests were performed; measurement of von Willebrand factor antigen (vWF:Ag), albumin and cortisol. In both groups, vWF concentration remained stable during the non‐gestational oestrous cycle, but increased during pregnancy, with the highest value observed at parturition. Increases of 70% and 124% in vWF were seen in GI and GII, respectively, compared to anestrus. No correlation was found between vWF and cortisol. Values of vWF:Ag changed during pregnancy, with a peak at parturition, both in vWD affected and unaffected animals. Values of vWF were not altered in the different phases of the oestrous cycle following pregnancy in both groups. Evaluation of vWF during pregnancy can cause false negative results for vWD, but assessment can be performed at any point in the oestrous cycle of non‐pregnant bitches.     

Decline in whale shark size and abundance at Ningaloo Reef over the past decade: The world’s largest fish is getting smaller

Over-exploitation of whale sharks threatens the future of these wide-ranging pelagic fish. A long-term continuous record (4436 sightings) from a large aggregation (300-500 resident individuals) of whale sharks at Ningaloo Reef, Western Australia shows that mean shark length declined linearly by nearly 2.0 m and relative abundance measured from ecotourism sightings (corrected for variation in search effort and environmental stochasticity) has fallen by approximately 40% over the last decade. This population-level result confirms previous predictions of population decline based on projection models parameterised using mark-recapture estimates of survival. The majority of these changes are driven by reductions in the number of large individuals in the population. Phenomenological time series models support a deterministic (extrinsic) decline in large females, although there was some evidence for density dependence in large males. These reductions have occurred despite the total protection of whale sharks in Australian waters. As this species is highly migratory, the rapid change in population composition over a decade (<1 whale shark generation) supports the hypothesis of unsustainable mortality in other parts of their range (e.g., overfishing), rather than the alternative of long-term abiotic or biotic shifts in the environment. As such, effective conservation of whale sharks will require international protection, and collaborative tagging studies to identify and monitor migratory pathways.