Mercury speciation in open ocean waters

Vital to our understanding of the biogeochemical cycling of Hg and the origin of the enhanced monomethylmercury (MMHg) concentrations in biota is knowledge of the sources, behavior and fate of methylated Hg species in natural waters. Methylated Hg species, dissolved gaseous and reactive mercury were measured in the equatorial Pacific Ocean in early 1990. Both dimethylmercury (DMHg) and MMHg were found in the subthermocline waters of the equatorial Pacific Ocean. Maxima in alkylmercury species in the O₂ minimum region coincided with a decrease in reactive mercury. A significant inverse correlation between DMHg, and MMHg, concentration and O₂ content was observed. A maximum in reactive mercury was observed in the region of the thermocline, with similar concentrations in the surface and deeper waters. Atmospheric deposition is not a significant source of MMHg to this region. The data suggest formation of alkylmercury species in the low oxygen zone, with Hg(II) being the most likely substrate. A model for the cycling of Hg species in the equatorial Pacific Ocean is presented. These results are the first direct evidence of a significant open ocean source of methylated Hg species and suggest a pathway for mercury accumulation in pelagic fish.     

Intraspecific variation in 16S rRNA gene of Mycoplasma synoviae determined by DNA sequencing

Mycoplasma synoviae (MS) is an important avian pathogen may cause both respiratory disease and joint inflammation synovitis in poultry, causing economic losses to the Brazilian poultry industry. The genotypic variation in 16S rRNA gene is unknown. Partial sequences of 16S rRNA gene of 19 strains of M. synoviae were sequenced and analyzed in order to obtain molecular characterization and evaluation of the genetic variability of strains from distinct Brazilian areas of poultry production. Different polymorphic patterns were observed. The number of polymorphic alterations in the studied strains ranged from 0 to 6. The nucleotide variations, including deletion, insertion and substitutions, ranged from 3 to 5. The genotypic diversity observed in this study may be explained by spontaneous mutations that may occur when a lineage remains in the same flock for long periods. The culling and reposition in poultry flocks may be responsible for the entry of new strains in different areas.     

Accuracy of an oscillometric blood pressure monitor during phenylephrine-induced hypertension in dogs

OBJECTIVE: To examine the agreement between direct arterial blood pressure measurements obtained from 2 arteries and indirect blood pressure measurements obtained with an oscillometric blood pressure monitor (OBPM) during normotension and phenylephrine-induced hypertension in dogs. ANIMALS: 16 male Beagles. PROCEDURES: In anesthetized dogs, arterial catheters were placed in the lingual and dorsal pedal arteries for measurement of arterial blood pressure. A blood pressure cuff was placed on either the dog's fore- or hind limb and connected to an OBPM. Systolic, diastolic, and mean arterial blood pressures (SAP, DAP, and MAP, respectively) were recorded from both arteries and the OBPM every 5 minutes for 30 minutes (baseline), during a 30-minute period in which dogs received a phenylephrine infusion IV to induce hypertension, and for 30 minutes after discontinuation of the infusion. Mean differences in blood pressure values and confidence intervals were calculated to compare the indirect and direct measurement techniques. RESULTS: In dogs, oscillometry underestimated SAP during normotension, and the difference between oscillometric and direct measurements increased during hypertension. Oscillometry underestimated DAP, but the difference between oscillometric and direct measurements decreased during hypertension. There was close agreement among techniques for MAP determinations. Biases between direct measurements and OPBM blood pressure values measured from dogs' forelimbs or hind limbs were not significantly different. CONCLUSIONS AND CLINICAL RELEVANCE: In normotensive dogs, oscillometric measurements of MAP and SAP agreed more closely with direct arterial pressure measurements than oscillometric estimates of DAP. Oscillometric measurement of MAP was accurate during both normotension and hypertension in dogs.     

Factors associated with the clinical diagnosis of foot and mouth disease during the 2001 epidemic in the UK

The purpose of this investigation was to identify factors associated with the clinical diagnosis of foot and mouth disease during the 2001 epidemic in the United Kingdom. Using logistic regression, we compared: (1) reports of suspect disease that resulted in the declaration of FMD to reports that did not, and (2) laboratory-positive cases to laboratory-negative cases. From 6,801 reports of suspect disease, 2,026 cases of FMD were identified. Suspect cases were more likely to become clinical cases if: (1) the report originated from the disease control authorities ('active surveillance') rather than the public, usually farmers ('passive surveillance'); (2) cattle were the species suspected of disease, as opposed to sheep; (3) the report was filed during the peak of the epidemic; (4) the reporting premises was within 3 km of an FMD case detected within the previous 2 weeks; or (5) the report originated from certain local disease control centres. There were significant two-way interactions between: type of surveillance and species suspected of disease, type of surveillance and proximity of other infected premises, species suspected and time in the epidemic, and time in the epidemic and proximity of other infected premises. Clinical cases were more likely to be laboratory positive if: (1) they were found by passive versus active surveillance, (2) cattle were suspected of disease (versus sheep), (3) oldest lesions were less than 3 days, (4) the report was filed at any time other than the peak of the epidemic, or (5) the report originated from certain local disease control centres. Significant two-way interactions were found between: type of surveillance and species suspected of disease, and type of surveillance and time in the epidemic.     

Human-carnivore conflict in China: a review of current approaches with recommendations for improved management

Human-wildlife conflict (HWC) is a conservation concern that increasingly threatens the continued existence of some of the world's most endangered species. With an increase in human population, urban sprawl and subsequent encroachment on wild land, human and wildlife interaction has become inevitable. In the majority of cases, this interaction results in a negative outcome for humans, wildlife or both. In China, these key elements, along with a decrease in wild prey species, have resulted in the expansion of HWC encounters, and the need for alleviating this conflict has become a conservation priority. Loss of human life, livestock and/or crops is most often the catalysts that fuel HWC. Techniques to alleviate conflict around the world have included preventative measures and mitigation techniques, such as financial compensation and other incentive programs. Both types of measures have had variable success. We review the current status of human-carnivore conflict management in China, and, drawing lessons from around the globe, we make recommendations for improving conservation management in China. For example, an increase in law enforcement in nature reserves is vital to reducing human disturbance in prime carnivore habitat, thereby reducing conflict encounters. Also, modifications to current wildlife compensation programs, so that they are linked with preventative measures, will ensure that moral hazards are avoided. Furthermore, investigating the potential for a community self-financed insurance scheme to fund compensation and increasing efforts to restore wild prey populations will improve the outcome for wildlife conservation. Ultimately, HWC management in China will greatly benefit from an integrative approach.     

Integrating in situ quantitative geographic information tools and size‐specific,laboratory‐based growth zones in a dynamic river‐mouth estuary

• 1. The ultimate determination of coastal habitat suitability requires the integration of both dynamic (i.e. water mass characteristics) and stationary (structural) habitats. An approach using real‐time streamed data collection, remote sensing, and GIS modelling to compare and contrast seasonal and spatial patterns in these habitat components of the eastern and western distributaries of the lower Pascagoula River estuary is described.
• 2. Structural and dynamic habitat characteristics are described using GIS and integrated with published growth data on juvenile mullet (Mugil spp.) and spot (Leiostomus xanthurus) to reveal zones of accelerated growth. Both mullet and spot had their greatest growth when water temperature and salinity (dynamic habitat) were physiologically optimal. The lack of spatial difference in the dynamic habitat between distributaries resulted in no growth zone differences for both species.
• 3. The integration of the growth zones with the structural habitat component showed that the west distributary, with its greater availability and reduced fragmentation of main channel marsh edge, should provide a greater area of essential fish habitat than the east distributary for juvenile spot, a marsh‐edge associate. Because juvenile mullet are less associated with structural wetland habitat, growth zones and the stationary (structural) habitat were not integrated.
• 4. The approach of integrating real‐time geo‐referenced water quality data with regional fish growth‐rate data is an important step towards a quantitative understanding of the hierarchical nature and inherent variability of dynamic coastal environments. The use of this holistic approach should lead to more effective management of estuarine systems, especially in regard to potential impacts within the estuary's watershed and to its coupling with offshore environments.

Copyright © 2007 John Wiley & Sons, Ltd.     

SNAKEBITE IN THE HORSE

Four cases of snakebite in horses are presented. Diagnosis was made on clinical signs in all, plus fang punctures in 2 cases. Tiger snake antivenene was used in the treatment of 2 patients and these recovered rapidly. Of the 2 in which antivenene was not used, 1 severely affected horse died. The clinical signs which were observed were those of progressive general paralysis and were entirely referable to the neurotoxic component of the venom.