Assessing Biogeography of Coffee Rust Risk in Brazil as Affected by the El Niño Southern Oscillation.

The El Niño Southern Oscillation (ENSO) is an oceanic-atmospheric phenomenon influencing worldwide weather and climate. Its occurrence is determined by the sea surface temperature (SST) anomaly of the 3.4 Niño region in the Pacific Ocean (5°N-5°S, 120°-170°W). El Niño (EN), Neutral (NT), and La Niña (LN) are the three possible phases of ENSO, respectively, for warm, normal, and cold SST anomaly. As in other regions around the world, weather in Brazil is influenced by ENSO phases. The country is the major coffee producer in the world, and production is strongly influenced by weather conditions, which affect plant yield, harvest quality, and interactions with pests and diseases. Coffee leaf rust (CLR), caused by the fungus Hemileia vastatrix, is a major cause of coffee yield and quality losses in Brazil, and requires fungicide spray applications every season. Because CLR is highly influenced by weather conditions, it is possible to use weather variables to simulate its progress during the cropping cycle. Therefore, the aims of this study were to estimate CLR infection rate based on a validated empirical model, which has daily minimum air temperature and relative humidity as inputs, and to assess the extent of ENSO influence on the annual risk of this disease at 45 sites in Brazil. Cumulative infection rates (CIR) were estimated daily from October to June of each growing season and location, based on the prevailing ENSO phase. Differences between the extreme phases (EN-LN) were assessed by the Two-One-Sided-Tests (TOST) method. Analysis of data from eight sites, located mainly in Paraná State, provided evidence of CIR differences between EN and LN phases (G1). Evidence of no difference of CIR between EN and LN was found in 18 sites (G2), whereas 19 sites showed no evidence of differences (G3) due to relatively large variation of CIR within the same ENSO phase. The G1 sites are located mostly in Southern Brazil, where ENSO exerts a well-defined influence on rainfall regime. In contrast, the G2 sites are mainly in Minas Gerais State, which is characterized as a transition region for ENSO influence on rainfall. The G3 sites are located between the northern region of Minas Gerais State and southern region of Bahia State, which is characterized by a subhumid climate that is usually very dry during winter, and where rainfall can vary up to 300% from one year to another, influencing relative humidity and resulting in a high CIR variability. Therefore, ENSO had a well-defined influence on CIR only in Paraná State, a region with minor importance for coffee production in Brazil. No ENSO influence was found in more northerly zones where the majority of Brazilian coffee is produced. This is the first evidence of ENSO-linked regional impact on the risk of coffee rust.

Genetic and virulence variability among Erwinia tracheiphila strains recovered from different cucurbit hosts.

The causal agent of cucurbit bacterial wilt, Erwinia tracheiphila, has a wide host range in the family Cucurbitaceae, including economically important crops such as muskmelon (Cucumis melo), cucumber (C. sativus), and squash (Cucurbita spp.). Genetic variability of 69 E. tracheiphila strains was investigated by repetitive-element polymerase chain reaction (rep-PCR) using BOXA1R and ERIC1-2 primers. Fingerprint profiles revealed significant variability associated with crop host; strains isolated from Cucumis spp. were clearly distinguishable from Cucurbita spp.-isolated strains regardless of geographic origin. Twelve E. tracheiphila strains isolated from muskmelon, cucumber, or summer squash were inoculated onto muskmelon and summer squash seedlings, followed by incubation in a growth chamber. Wilt symptoms were assessed over 3 weeks, strains were reisolated, and rep-PCR profiles were compared with the inoculated strains. Wilting occurred significantly faster when seedlings were inoculated with strains that originated from the same crop host genus (P<0.001). In the first run of the experiment, cucumber and muskmelon strains caused wilting on muskmelon seedlings at a median of 7.8 and 5.6 days after inoculation (dai), respectively. Summer squash seedlings wilted 18.0, 15.7, and 5.7 dai when inoculated with muskmelon-, cucumber-, and squash-origin strains, respectively. In a second run of the experiment, cucumber and muskmelon strains caused wilting on muskmelon at 7.0 and 6.9 dai, respectively, whereas summer squash seedlings wilted at 23.6, 29.0 and 9.0 dai when inoculated with muskmelon-, cucumber-, and squash-origin strains, respectively. Our results provide the first evidence of genetic diversity within E. tracheiphila and suggest that strain specificity is associated with plant host. This advance is a first step toward understanding the genetic and population structure of E. tracheiphila.

An anatomical study to evaluate the risk of pulpar exposure during mechanical widening of equine cheek teeth diastemata and 'bit seating'.

REASONS FOR PERFORMING STUDY: Cheek teeth (CT) diastemata are a major equine dental disorder that can be treated by mechanically widening the diastemata. There is limited anatomical knowledge of the spatial relationships of the individual pulps to the adjacent interproximal surfaces; on the risks of exposing the 6th pulp horn when performing the clinically unproven 'bit seating' procedure on Triadan 06s. OBJECTIVES: To describe the anatomical relationships between the occlusal and interproximal surfaces of CT and the adjacent pulp horns; and between the 6th pulp horn and the occlusal and rostral surfaces of Triadan 06s. METHODS: The CT from 30 skulls of horses subjected to euthanasia for non-dental reasons were sectioned to expose the rostrally and caudally situated pulp horns to allow the anatomical relationships between the pulp horns and the occlusal and interproximal aspects of the CT to be assessed. RESULTS: Pulp horns were mean ± s.d. of 5.74 ± 1.45 (range 1.3-10.8 mm) from the nearest interproximal surface, with 5.3% of pulp horns being <3.5 mm from the interproximal surface. In contrast to expectations, pulps tended to became closer to the interproximal surface (and also to the occlusal surface) with increasing age. Teeth with physiologically tall clinical crowns, and also those in the Triadan 09 position had pulps that were closer to the interproximal surfaces than the remaining CT. The more caudally situated pulp horns, i.e. in particular, the 4th maxillary and 5th mandibular pulp horns were closer to the interproximal surfaces than the remaining pulp horns and these pulp horns also had the thinnest sub-occlusal secondary dentine. Pulps that were close to the interproximal surface were also found to be close to the occlusal surface of the CT. CONCLUSIONS AND POTENTIAL RELEVANCE: While diastema widening is theoretically safe between the majority of CT, a small proportion of pulp horns are only 1.3 mm from an interproximal surface and others lie just 1.6 mm beneath the occlusal surface, and such pulps are at risk of pulpar exposure and to thermal injury during this procedure. The risk of pulpar exposure increases when dental tissue is removed from the caudal aspects of CT.

Correlation of resting and exercising endoscopic findings for horses with dynamic laryngeal collapse and palatal dysfunction.

REASONS FOR PERFORMING STUDY: To correlate resting and exercising endoscopic grades of laryngeal function in horses undergoing high-speed treadmill endoscopy (HSTE) using the Havemeyer grading system. To correlate dorsal displacement of the soft palate (DDSP) seen at rest with palatal function during exercise. METHODS: Records of horses that underwent HSTE examination (1999-2009) were reviewed. Resting laryngeal function score and other abnormalities noted on resting endoscopy were recorded as were results of HSTE. Results of resting and exercising endoscopic findings were correlated. RESULTS: 281 horses underwent HSTE. There was significant correlation between grade of laryngeal function at rest (grades 1-4) and exercise (ρ=0.53, P<0.001) and between resting subgrades 3.1, 3.2 and 3.3 and exercising grades of laryngeal function (ρ=0.43, P=0.0017). DDSP was observed at rest significantly more often in horses that developed DDSP during HSTE than those without DDSP during HSTE (RR=4.1, P<0.001). The sensitivity and specificity of DDSP seen during resting endoscopy as a test for DDSP occurring during exercise were 25.5 and 95.1% respectively (positive predictive value 0.57, negative predictive value 0.83). CONCLUSIONS AND POTENTIAL RELEVANCE: The results of the current study support the use of the Havemeyer system for grading laryngeal function in the resting horse, and corroborate findings of previous studies correlating resting and exercising palatal abnormalities. Studies that use the presence of spontaneous DDSP during resting endoscopic examination as an inclusion criterion for investigating efficacy of treatments for DDSP are likely to have a low proportion of horses with false positive diagnoses.

A study of the thickness of cheek teeth subocclusal secondary dentine in horses of different ages.

REASONS FOR PERFORMING STUDY: There is limited knowledge on the thickness of subocclusal secondary dentine in equine cheek teeth (CT). HYPOTHESES: Subocclusal secondary dentine is of consistent thickness above different pulp horns in individual horses and its thickness increases with age. METHODS: 408 permanent CT were extracted post mortem from 17 horses aged 4-30 years, with no history of dental disease. The CT were sectioned longitudinally in the medio-lateral (bucco-palatal/lingual) plane through each pulp horn, and the thickness of the secondary dentine overlying each pulp horn was measured directly. RESULTS: The subocclusal thickness of secondary dentine above the pulp horns of CT varied from a mean thickness (above all pulp horns) of 12.8 mm (range 5-33 mm) in a 4-year-old to 7.5 mm (range 2-24 mm) in a 16-year-old horse. There was wide variation in the depth of subocclusal secondary dentine above different pulp horns, even within the same CT. In contrast to expectations, occlusal secondary dentine thickness did not increase with age. There were no significant differences in occlusal secondary dentine thickness between rostral and caudal, or medial and lateral aspects of the CT, or between contralateral CT. Mandibular CT had significantly thicker subocclusal secondary dentine than maxillary CT. Pink coloured secondary dentine was sometimes found 1-3 mm occlusal to the pulp horn in sectioned CT and this was likely caused by artefactual blood staining from the underlying pulp during sectioning. CONCLUSIONS: The thickness of subocclusal secondary dentine varies greatly between individual pulp horns, teeth and individual horses and can be as low as 2 mm over individual pulp horns. POTENTIAL RELEVANCE: Due to the great variation in the thickness of subocclusal secondary dentine between horses, and even between pulp horns in individual CT, there is a risk of exposure or thermal damage to pulp and thus of apical infection, even with modest therapeutic reductions of CT occlusal overgrowths. In the light of these findings, great care should be taken when reducing equine CT overgrowths and larger dental overgrowths should be reduced in stages.

Post mortem survey of peripheral dental caries in 510 Swedish horses.

REASONS FOR PERFORMING STUDY: Peripheral caries (PC) of equine teeth is a poorly described disorder that can cause serious clinical problems if it progresses. OBJECTIVES: To assess the prevalence, sites and severity of PC in a population of Swedish horses. METHODS: A post mortem study of 510 equine skulls was performed in 2 Swedish equine abattoirs. RESULTS: PC only affected the cheek teeth (CT) and was present in 6.1% (31/510) of skulls. It affected mainly the peripheral cementum, and 87% of PC in the 29 affected mature horses occurred in the 3 caudal CT (Triadan 09-11). Concurrent infundibular caries involving most maxillary CT (mean 9.7/skull) was present in 32% of skulls affected with PC. Trotting horses (mean age 8.1 years) believed to be on a high concentrate and silage diet were preferentially affected with PC in this population. Food was usually tightly adherent to the PC lesions and this feature may have promoted the progression of the disease. Significantly increased levels of diastemata were present in PC-affected horses, and periodontal disease was present in areas adjacent to some PC lesions. CONCLUSIONS: PC is a relatively common disorder of horses under certain management conditions that can progress to cause serious dental disorders, especially if concurrent, widespread infundibular caries is present. POTENTIAL RELEVANCE: Equine clinicians should be aware of this significant dental disorder and research into its aetiopathogenesis, possible prevention and treatment are required.

Histological and histochemical characterisation of the equine soft palate muscles.

REASONS FOR PERFORMING STUDY: Dysfunction of the muscles is implicated in the pathogenesis of intermittent dorsal displacement of the soft palate (DDSP) in exercising horses. The histological features of normal equine soft palate muscles have not been previously described. OBJECTIVE: To describe the histological and morphometric features of normal equine soft palate muscles. METHODS: The palatinus, palatopharyngeus, levator veli palatini and tensor veli palatini muscles of 6 Thoroughbred type horses were examined histologically and histochemically to assess their general morphology, fibre-type distribution and mean fibre diameter. RESULTS: The muscles of all 6 specimens showed very similar characteristics, including a low proportion of type 1 muscle fibres in the 4 different muscles examined, with the 3 muscles innervated by the pharyngeal branch of the vagus (i.e. palatopharyngeus, palatinus and levator veli palatini) having significantly fewer (P<0.005) type 1 muscle fibres compared to the tensor veli palatini. The mean fibre diameters were significantly (P<0.05) smaller in type 1 than type 2 fibres in all muscles except the palatinus. Considerable variability in mean fibre size diameter was evident in all muscles examined, with type 1 fibres in the levator veli palatini and rostral fasciculus of the palatopharyngeus and both fibre types in the caudal fasciculus of the palatopharyngeus having the most marked variation, with coefficients of variation >250 and the latter also having high levels of endomysial connective tissue. The palatinus had least variation in fibre size. CONCLUSION AND CLINICAL RELEVANCE: Morphological characterisation of the normal soft palate muscles may provide reference values for future comparative studies with samples obtained from horses with palatal dysfunction. The palatinus appears to be the best muscle to histologically examine for evidence of muscle abnormality.

Anatomical studies of maxillary cheek teeth infundibula in clinically normal horses.

REASONS FOR PERFORMING STUDY: Although clinical disorders of equine maxillary cheek teeth (CT) infundibula are common, anatomical knowledge of these structures is poor. HYPOTHESIS: Anatomical examinations of sectioned CT infundibula will better define their shapes and sizes and allow identification of infundibular cemental variations and changes. MATERIAL AND METHODS: Cheek teeth were extracted post mortem from 33 horses, aged 3-30 years, without a clinical history of dental disease. The CT were sectioned longitudinally in the bucco-palatal plane through the widest aspects of both infundibula. The infundibular surfaces were then assessed morphologically, including by measurements of areas of cemental variations and changes. Specimens from selected teeth were examined histologically. RESULTS: Infundibular length and infundibular surface area, and infundibular length as a proportion of dental crown length progressively decreased with age, e.g. infundibular length was up to 89 mm after eruption to 2 mm in one older horse. Triadan 06 and 09 positions had significantly shorter CT and therefore infundibula, than the other 4 Triadan positions. Only 11.7% of infundibula were filled completely with normal appearing cementum, 8.2% of infundibula (especially the 09 position) had complete cemental caries; 22.6% of infundibula had areas with cemental hypoplasia and the remaining 57.5% of infundibulae had a variety of other cemental appearances, including the presence of central defects, localised occlusal caries and cemental discolourations. Histology showed the presence of an apical blood supply to infundibular cement in younger horses. CONCLUSIONS: Anatomical variations of CT infundibular cement are very common and some changes, such as areas of localised cemental hypoplasia, may predispose to the development of infundibular caries. POTENTIAL RELEVANCE: This more complete description and quantification of CT infundibular anatomy should allow more rational assessment and treatment of equine CT infundibular disorders.

Morphological study of tracheal shape in donkeys with and without tracheal obstruction.

REASON FOR PERFORMING STUDY: There is limited information on the gross tracheal morphology of donkeys with or without tracheal abnormalities. OBJECTIVES: To: 1) examine the morphology of tracheas of donkeys with and without clinical and/or post mortem evidence of tracheal obstruction; 2) record the cross-sectional dimensions and shapes of tracheal rings at fixed sites; and 3) document prevalence, sites and characteristics of detected tracheal abnormalities. METHODS: The tracheas of 75, predominantly aged (median age 30 years, range 7-48 years) donkeys that died or were subjected to euthanasia on humane grounds were examined. Five had severe dyspnoea due to tracheal obstruction (with intercurrent lung disease in 3), while 7 had post mortem evidence of severe tracheal airway obstruction. Every 5th tracheal ring was dissected free and the inner and outer vertical and transverse dimensions and cross sectional areas were measured. Each dissected ring was photographed and the shape of the trachea was classified as normal or, in one of 6 abnormal grades, according to the type and degree of structural abnormality present. RESULTS: The tracheas had a mean of 43 (range 34-50) tracheal rings that tended to be more oval in shape in the distal cervical region. Only 31.2% of rings examined had a circular to oval shape. Dorso-ventral flattening was present in 0.9% of tracheal rings, dorsal ligament separation in 24.4%, slight cartilage deformity in 26.0%, moderate cartilage deformity in 10.4%, marked cartilage deformity in 1.9% and miscellaneous other abnormalities in 4.9% of tracheal rings. The 12 donkeys with ante or post mortem evidence of tracheal obstruction had significantly increased tracheal abnormality grade in comparison to the remaining donkeys. CONCLUSIONS AND POTENTIAL RELEVANCE: Structural tracheal abnormalities are present in most old donkeys, but generally do not cause clinical problems in these sedentary animals unless intercurrent pulmonary disease is present.

A histological and ultrastructural study of equine peripheral caries.

BACKGROUND: Peripheral caries (PC) has recently been shown to affect over half of UK and Australian horses. OBJECTIVES: To examine affected cheek teeth histologically and ultrastructurally, to assess the possible route(s) of carious infection into the dental tissues and to further describe the pathological changes in affected teeth. STUDY DESIGN: Descriptive pathological study. METHODS: Four control and 16 cheek teeth with different grades of PC were examined grossly, histologically and by electron microscopy. RESULTS: Cariogenic bacteria from plaque entered peripheral cementum perpendicular to the sides of teeth alongside Sharpey's fibres or vascular channels or more horizontally alongside exposed intrinsic fibres and cemental growth lines. Subsequent intra-cemental bacterial spread created different patterns of caries including vertical and horizontal flake-like patterns; deep, large flask-shaped or smaller superficial ellipsoid-shaped lytic lesions. Cemental caries progressed to affect enamel, dentine and even pulp. Gross examination underestimated the degree of caries observed on histological evaluation. MAIN LIMITATIONS: No dental histories were available; all teeth were examined on a single occasion. CONCLUSION: Equine PC causes different patterns of cemental lesions that appear dependent on the route of cariogenic bacterial invasion. Progression of caries can lead to pulpitis and tooth loss. Gross examination can underestimate the true extent of caries.

A microbiome analysis of equine peripheral dental caries using next generation sequencing.

BACKGROUND: Although, peripheral caries (PC) affects almost half of UK horses, no comprehensive microbiological study has been performed on this disorder. As a high proportion of oral bacteria cannot be conventionally cultured, molecular microbiological techniques such as Next Generation Sequencing are required to examine the complex oral bacteria community. OBJECTIVES: To identify the microbiota involved in equine PC, including comparing microbiota at the more commonly and severely affected three caudal cheek teeth with the less commonly affected three rostral cheek teeth. STUDY DESIGN AND METHODS: Equine dental plaque samples were collected from the palatal aspects of cheek teeth of 63 horses. DNA was isolated and amplified using PCR, targeting the V4 region of the 16S rRNA gene and Next Generation Sequencing of these gene amplicons was performed. The acquired data were processed and analysed using Mothur and R. RESULTS: Streptococcus species was the genus most commonly associated with equine PC, whereas Gemella species was the genus most associated with the control group. In a further analysis where the rostral and caudal cheek teeth were compared with each other and with the control group. Veillonella species was the most commonly associated genus with PC of the rostral cheek teeth, Streptococcus species was the most associated genus with the caudal cheek teeth, and Corynebacterium with the control group. MAIN LIMITATIONS: Some bacteria can have multiple heterogeneous copies of the 16S rRNA gene, which can affect the estimation of their relative abundance. CONCLUSIONS: Similar to caries studies in other species, acidogenic and aciduric microorganisms including Streptococcus species were found to be associated with equine peripheral caries.

Clinical dental examinations of 357 donkeys in the UK. Part 1: prevalence of dental disorders.

REASONS FOR PERFORMING STUDY: Dental disorders have a high prevalence in older donkeys and horses, but the nature and pathogenesis of many of these disorders have yet to be established. OBJECTIVES: The identification and determination of the prevalence of important dental disorders in different age groups in a large single population of donkeys, to establish a better understanding of the nature and pathogenesis of these disorders. METHODS: A prospective cross-sectional study was performed on the donkey population at The Donkey Sanctuary with detailed oral examinations of 357 donkeys within 7 different age groups (age range 2-53 years) recorded. RESULTS: The prevalence of dental disease in all donkeys was 73%, increasing in prevalence from 28% in the youngest to 98% in the oldest age group. There was an increase in prevalence of commonly recognised dental disorders with increasing age, such as: diastemata (3.8% in youngest to 86% in oldest group); missing teeth (0-56%); overgrown teeth (15-86%); worn teeth (8-84%); displaced teeth (0-38%); and periodontal disease (0-28%). CONCLUSIONS: There was a significant increase in the prevalence of dental disorders with increasing age with the largest significant increase for most dental disorders occurring in the 15-20 year age group. POTENTIAL SIGNIFICANCE: Most dental disorders significantly increase in prevalence in the 15-20 year age group and, therefore, prophylactic geriatric dental treatment in donkeys should be commenced from age 15 years.

Clinical dental examinations of 357 donkeys in the UK. Part 2: epidemiological studies on the potential relationships between different dental disorders, and between dental disease and systemic disorders.

REASONS FOR PERFORMING STUDY: Dental disease has been shown to be a risk factor for weight loss and colic in horses. No extensive clinical studies in donkeys have investigated the potential relationship between different dental disorders, or between dental disease and systemic disorders. OBJECTIVES: To determine possible associations between dental disease and body condition score, weight loss, the need for supplemental feeding and prevalence of colic in donkeys of all ages, and to gain a better understanding of the pathogenesis of dental disease by the determination of associations between different dental disorders. METHODS: A prospective cross-sectional analysis of clinical dental examinations of 357 donkeys in The Donkey Sanctuary, Sidmouth was performed. Other epidemiological factors such as estimated age group, body condition score, weight loss, medical history and supplemental feeding were also recorded, and multiple regression analyses were performed to determine possible associations. RESULTS: Donkeys from older age groups were more likely to have dental disease, poor body condition score and suffered previous colic episodes. The presence of dental disease was also significantly associated with weight loss, colic, low body condition score and the need for supplemental feeding. The presence of diastemata, periodontal disease, wave mouth, smooth mouth and step mouth are frequently associated with the presence of other dental disorders. CONCLUSIONS: In addition to oral-related pain, dental disease can cause significant systemic disorders and so has increased welfare implications in donkeys. Some dental disorders promote the development of other types of dental abnormalities and thus increase the severity of dental disease in individual animals. POTENTIAL SIGNIFICANCE: Effective treatment of dental disorders slows down the progression of dental disease and decreases the risk of developing some medical disorders such as colic and weight loss that are associated with dental disease.

Efficacy of thermal cautery for intermittent dorsal displacement of the soft palate as compared to conservatively treated horses: results from 78 treadmill diagnosed horses.

REASONS FOR PERFORMING STUDY: Previously, objective comparisons of surgical procedures to relieve dorsal displacement of the soft palate (DDSP) have been limited by the presumptive basis of the diagnostic measures applied. OBJECTIVES: To assess and compare the efficacy of thermal cautery surgery to conservatively treated controls in racehorses definitively diagnosed with idiopathic intermittent DDSP. HYPOTHESIS: Both conservative and surgical treatments have a beneficial result on racing performance in racehorses affected with DDSP. METHODS: Race records were obtained for Thoroughbred racehorses definitively diagnosed with DDSP using high-speed treadmill endoscopy. Racing performance was assessed based on prize money won. RESULTS: Forty-eight horses that underwent thermal cautery and 30 conservatively treated controls were included. Pretreatment earnings significantly decreased in the race immediately prior to diagnosis. A high proportion of previously raced horses returned to racing after both treatments (90-96%). Intrahorse comparison of earnings in 3 races pre- vs. post treatment showed that 53% of conservatively treated horses and 36% of the thermal cautery group had improved performance. Although the difference between these 2 groups may be interpreted as being clinically significant, it was not statistically significant. CONCLUSIONS AND POTENTIAL RELEVANCE: A higher percentage of conservatively treated controls had improved individual performance compared to horses treated with thermal cautery. Thermal cautery appears less effective than other previously published surgical treatments for DDSP. Comparison of the 2 treatment methods should be interpreted cautiously because treatments were not randomised, resulting in baseline variability between groups.

Use of tongue ties in thoroughbred racehorses in the United Kingdom, and its association with surgery for dorsal displacement of the soft palate.

The prevalence of the use of tongue ties, calculated from 60 randomly selected race meetings held in the UK during 2001 to 2003, was 5.0 per cent. After its first use on an individual horse a tongue tie was used in an average of 77 per cent of its races during the first 12 months, but after this time period, in only 55 per cent of its races. Thirty-nine per cent of horses that underwent surgery for dorsal displacement of the soft palate raced with a tongue tie preoperatively, and 41 per cent of these surgical cases raced with a tongue tie postoperatively.

Bilateral laryngeal paralysis associated with hepatic dysfunction and hepatic encephalopathy in six ponies and four horses.

Six ponies and four horses with a mean (sd) age of 15.9 (6.0) years developed sudden-onset bilateral laryngeal paralysis (BLP) in association with hepatic dysfunction. Nine of them had been referred for the investigation of respiratory distress, and one pony had been referred for weight loss before BLP developed. Nine of the animals had clinicopathological evidence of liver disease, and nine had histological evidence of liver disease. All of the animals had one or more of the following: hepatic encephalopathy (in eight), hyperammonaemia (in six) and endoscopic evidence of BLP (in nine). Three of the animals had signs of pituitary pars intermedia dysfunction, a diagnosis supported in two by endocrine function testing, and in two by histopathological examination. Histopathological examination of the intrinsic laryngeal musculature and recurrent laryngeal nerves of four of the horses and of the region of the nucleus ambiguus of two did not reveal any abnormalities. Three of the animals were euthanased after they had first been examined, and one improved temporarily before the condition recurred. A temporary tracheostomy was performed in six of the animals, five of which subsequently died or were euthanased; one pony recovered.

Dimensions of diastemata and associated periodontal food pockets in donkey cheek teeth.

Equine cheek teeth (CT) diastemata often cause deep periodontal food pocketing and are therefore regarded as a painful dental disorder of equidae. However there appears to be no information available on the size or shape of these diastemata. This post mortem study examined 16 donkey skulls (mean age = 32-years) containing 45 CT diastemata to define the anatomical shape and dimensions of these diastemata, and of the associated periodontal food pockets that occur with this disorder. Diastemata were found to more commonly involve mandibular (56.0%) compared with maxillary CT (44.0%), and 71.0% of these diastemata had adjacent intercurrent dental disorders that may have predisposed donkeys to the diastemata. The median widths of all diastemata were 2.0-mm at the occlusal surface and 3.1-mm at the gingival margin, with no diferences in widths between the lateral or medial aspects of diastemata. Diastemata were defined as open (60.00%) or valve (40.00%) based on their gross appearance. This classification was confirmed to be accurate by measurements that showed valve diastemata to have an occlusal to gingival width ratio of 0.4, in contrast to open diastemata where this ratio was 1.07. Food was impacted in 89.0% of diastemata, but all diastemata had adjacent periodontal disease. Periodontal food pocketing was present adjacent to 76.0% of diastemata, more commonly on the lateral aspect (73.0% prevalence; mean pocket depth = 4.1-mm) than the medial aspect (47.0% prevalence; mean pocket depth = 2.4-mm). The depth of periodontal pockets of diastemata was not associated with the height of the erupted crowns of adjacent CT.

Selection of nontarget arthropod taxa for field research on transgenic insecticidal crops: using empirical data and statistical power.

One of the possible adverse effects of transgenic insecticidal crops is the unintended decline in the abundance of nontarget arthropods. Field trials designed to evaluate potential nontarget effects can be more complex than expected because decisions to conduct field trials and the selection of taxa to include are not always guided by the results of laboratory tests. Also, recent studies emphasize the potential for indirect effects (adverse impacts to nontarget arthropods without feeding directly on plant tissues), which are difficult to predict because of interactions among nontarget arthropods, target pests, and transgenic crops. As a consequence, field studies may attempt to monitor expansive lists of arthropod taxa, making the design of such broad studies more difficult and reducing the likelihood of detecting any negative effects that might be present. To improve the taxonomic focus and statistical rigor of future studies, existing field data and corresponding power analysis may provide useful guidance. Analysis of control data from several nontarget field trials using repeated-measures designs suggests that while detection of small effects may require considerable increases in replication, there are taxa from different ecological roles that are sampled effectively using standard methods. The use of statistical power to guide selection of taxa for nontarget trials reflects scientists' inability to predict the complex interactions among arthropod taxa, particularly when laboratory trials fail to provide guidance on which groups are more likely to be affected. However, scientists still may exercise judgment, including taxa that are not included in or supported by power analyses.

Pathological studies of cheek teeth apical infections in the horse: 5. Aetiopathological findings in 57 apically infected maxillary cheek teeth and histological and ultrastructural findings.

Examination of 57 apically infected maxillary cheek teeth (CT) showed one or more viable pulps and minimal apical calcified tissue changes present in recently infected CT. With chronic infections, pulps were necrotic or absent, pulp horns were filled with food if occlusal pulpar exposure was present, and gross caries of dentine was occasionally present. With chronic infections, the apical changes varied from gross destructive changes in some teeth, to extensive proliferative calcified apical changes in others. Infundibular caries was believed to cause apical infection in just 16% of infected (maxillary) CT, anachoretic infection in 51%, periodontal spread in 12%, fractures and fissures in 9%, dysplasia in 5% and miscellaneous or undiagnosed causes in 7%. Histology showed viable pulp and absence of circumpulpar dentinal changes in some recently infected CT, but chronically infected teeth had loss of predentine and progressive destruction of the circumpulpar secondary, and even primary dentine, with bacteria identified within the dentinal tubules surrounding infected pulps. Tertiary dentine deposition was rarely detected. Scanning and transmission electron microscopy confirmed these histological findings and showed extensive destructive changes, especially to the dentinal architecture surrounding the pulp chambers of some infected teeth.

Treatment of equine cheek teeth by mechanical widening of diastemata in 60 horses (2000-2006).

REASON FOR PERFORMING STUDY: Cheek teeth (CT) diastemata are a significant cause of painful dental disease in horses and limited factual information is available on the treatment of this disorder. OBJECTIVE: To assess the response to mechanical widening in the treatment of diastema. METHOD: Details of the presenting signs and treatment of cases of CT diastema by widening were recorded and the response to treatment of these cases assessed by re-examinations and by obtaining follow-up information from owners. RESULTS: Sixty horses of various breeds, median age 9 years, with clinically significant CT diastemata were classified as having primary (inadequate rostro-caudal CT compression: n = 29) and secondary (to other dental abnormalities: n = 31) diastemata. Quidding was present in 82% of cases, weight loss in 35%, halitosis in 17% and bitting disorders in 12%; 85% of the identified CT diastemata involved mandibular CT and 15% maxillary CT, with caudal CT more commonly affected. Of 273 identified diastemata in the 60 horses, 207 were deemed to have significantly associated periodontal food pocketing and were widened to 4.5-5.5 mm diameter on their occlusal surface using a mechanical burr. The 29 horses with primary diastemata received a median of 1.3 treatments each and at 10 months following their last treatment 72% showed complete remission of signs and 28% showed good improvement. The 31 horses with secondary diastemata received a median of 2.2 treatments each and, at mean 9 months following their last treatment, 48% showed full improvement, 42% good improvement, 6% slight improvement and 3% no improvement. Inappropriate areas of the clinical crown were removed from 4 CT without causing pulpar exposure; one case was reported to have a transient oral infection post treatment and another developed an apical infection in a treated tooth that was unrelated to the diastema widening. CONCLUSION: Diastema widening is an effective treatment of periodontal pocketing in CT diastemata. POTENTIAL RELEVANCE: The described treatment of CT diastema widening by trained personnel is an effective and safe treatment, but repeated treatments are often necessary, especially with secondary diastemata.