Fungal sinusitis resulting in suspected trigeminal neuropathy as a cause of headshaking in five horses

Primary fungal sinusitis was identified in 5 horses displaying signs of headshaking. All 5 horses had fungal plaques adhered to the infraorbital canal (IOC). Headshaking signs were exhibited by 3 horses prior to treatment and 2 horses after treatment. Standing computed tomography (CT) identified erosion of the IOC in the 2 cases in which it was performed. Fungal culture and PCR identified 3 species of fungi, Rhizomucor pusillus, Scedosporium apiospermum and Aspergillus nidulans which have not previously been described as a cause of sinusitis in horses. Surgical debridement followed by topical antifungal therapy was used in all 5 horses. Recurrence of the fungal plaques in 4 horses necessitated further treatment. The headshaking signs and nasal discharge resolved in 3 horses allowing a return to their previous use. Two horses developed persistent headshaking signs despite multiple treatments. Primary fungal sinusitis should be considered as a cause of headshaking signs in horses, due to a suspected trigeminal neuropathy. Computed tomography is valuable in identifying erosion of the IOC which is not identified with conventional radiography. Three out of the 5 cases were treated successfully but permanent resolution of the fungal infection is difficult to achieve once the bone overlying the infraorbital nerve has been eroded.     

Effect of bandaging on second intention healing of wounds of the distal limb in horses

Objective   To evaluate the effect of a non-occlusive dressing incorporated in a 3-layer bandage on second intention healing of wounds of the distal portion of the limb.
Study Design   Untreated wounds in 33 adult horses used in four studies using the same wound-healing model conducted over 5 years.
Methods   Standardised, full-thickness wounds were made in the skin overlying the dorsomedial aspect of the mid-metacarpus; 17 horses were bandaged with a non-occlusive dressing covered by gauze-coated cotton wool that was compressed with adhesive tape; 16 horses were left unbandaged. Wounds were photographed weekly for 9 weeks and the images were analysed electronically.
Results   There were significant effects associated with bandage (P < 0.0001), week (P < 0.001), and bandage by week interaction (P < 0.0001). There was no difference in wound area at the first time-point after wound creation (P = 0.38). After week 1, there was a difference between bandaged and unbandaged wounds in wound area at each measurement until the end of the study. Bandaged wounds showed greater and more prolonged retraction. Unbandaged wounds retracted for 2 weeks before beginning to contract, whereas bandaged wounds continued to retract for 3 weeks. In bandaged wounds excess granulation tissue required regular trimming, but not in unbandaged wounds. There was no difference between groups in the total days to healing or the overall rate of healing.
Conclusions   These results should be treated with caution until validated with contemporaneous, controlled studies. Covering a wound with a non-occlusive dressing in a 3-layer bandage led to greater wound retraction, modulated the rate of wound contraction and promoted excessive granulation tissue. If excessive granulation tissue is excised regularly, bandaging has no effect on total time to healing.     

Detection of Minchinia occulta in samples of pearl oysters Pinctada maxima infected by Haplosporidium hinei

Objective   To determine if juvenile pearl oysters ( Pinctada maxima ) infected with Haplosporidium hinei are also infected with another haplosporidian parasite, Minchinia occulta .
Design   Archived samples of pearl oysters infected with H. hinei were examined using polymerase chain reaction (PCR) assays and in situ hybridisation (ISH) to analyse and identify haplosporidians. A 144-bp and 220-bp region of Minchinia DNA were targeted by PCR and amplified DNA from formalin-fixed H. hinei -infected pearl oyster samples was sequenced. A 25-bp oligonucleotide probe targeting a variable section of the parasite's small subunit rRNA gene was used in ISH.
Results   The results of DNA-based diagnostic assays supported each other. The sequences obtained by PCR were found to be almost identical to M. occulta from rock oysters and the ISH assay demonstrated infection with M. occulta in affected pearl oysters. ISH indicated a prevalence of infection of 26.7% in one of the previous outbreaks.
Conclusion   Pearl oyster spat are susceptible to infection by a Minchinia parasite, most likely M. occulta , which was recently identified in rock oysters within the pearl-producing zones of Western Australia and is associated with mortalities of up to 80% in this species. The occurrence of haplosporidian co-infections in pearl oysters suggests the immunocompetence of juvenile oysters may be an important factor in preventing infection and therefore preventing mortalities such as those occurring in the recent outbreaks of pearl oyster oedema disease.     

Risk factors for injury to the superficial digital flexor tendon and suspensory apparatus in Thoroughbred racehorses in New Zealand

AIM: To investigate risk factors for injury to the superficial digital flexor tendon (SDFT) and suspensory apparatus (SA) of the forelimbs in Thoroughbred racehorses in New Zealand. METHODS: Poisson and negative binomial regression, with exposure time represented by cumulative training days for each horse, were used to relate explanatory variables to the incidence rate (IR) of cases of inflammation of the SDFT (n=51), and injuries involving the SA (n=48) in a population of 1,571 commercially- trained racehorses over 554,745 study days. Only the first occurrence of an injury for any one horse was eligible for inclusion. Separate analyses were run for data from horses in training regardless of whether they had started in a trial or race, and using a subset of these data restricted to those preparations associated with at least one start in a trial or race. Results were reported as incidence rate ratios (IRR) and 95% confidence intervals (CI). RESULTS: Male horses had a higher risk of injury to the SA (IRR 2.57; p=0.005) and tended to have a higher risk of injury to the SDFT (IRR 1.74; p=0.09) than female horses. Increasing age was associated with increased risk of injury. Horses aged 4 and > or =5 years were 6.76 (p<0.001) and 15.26 (p<0.001) times more likely to incur injury to the SDFT, and 2.91 (p=0.02) and 3.54 (p=0.005) times more likely to incur injury to the SA, respectively, than 2-year-olds. Horses were more likely to suffer an injury to the SDFT or SA in a training preparation that was not associated with any starts in official trials or races compared with those preparations that were associated with more than one start (p<0.001), and more likely to injure the SA compared with preparations containing one start (p=0.03). The IR of injury to the SDFT tended to be lower between November-January (IRR 0.78; p=0.08) and February-April (IRR 0.75; p=0.08) compared with August-October. Incidence of injury to the SDFT or SA was not associated with the cumulative distance raced in the last 30 days of a training preparation. CONCLUSION: This study identified risk factors for injury to the SDFT and SA in Thoroughbred racehorses in New Zealand. Injuries were more likely in males, older horses and in horses in training preparations without any starts. There was no evidence of association between injury and cumulative high-speed exercise.     

Demonstration of regional differences in equine ventricular myocardial velocity in normal 2-year-old Thoroughbreds with Doppler tissue imaging

REASONS FOR PERFORMING STUDY: Doppler tissue imaging (DTI) is a novel noninvasive method by which myocardial velocity can be assessed directly and it allows regional, rather than global, cardiac function to be evaluated. HYPOTHESIS: That regional differences in myocardial velocities exist within the equine ventricle. OBJECTIVES: To develop a repeatable examination technique for DTI in horses, describe DTI findings in various regions of the normal equine ventricle, compare colour (CDTI) and spectral (SDTI) techniques of DTI, and document regional differences in myocardial velocity. METHODS: Five regions of the ventricles (right ventricular wall, interventricular septum and left, right and caudal regions of the left ventricle) were evaluated using SDTI and CDTI in 20 clinically normal Thoroughbreds age 2 years. Individual repeatability of the method was determined by examination of one 6-year-old Thoroughbred on 6 occasions. RESULTS: Three major movements were observed in the ventricular walls in systole, early diastole and late diastole. The interventricular septum had a complex pattern of movement. The left region of the left ventricle and interventricular septum had the most rapid movement. The individual repeatability of CDTI was poor, while in systole and early diastole, but not late diastole, SDTI produced repeatable estimates of maximal myocardial velocity. The different velocity estimates obtained with SDTI and CDTI are not interchangeable. Regional differences in the peak mean and maximal myocardial velocities were found in systole and early diastole (P<0.05), but were not identified in late diastole. CONCLUSIONS: The SDTI modality appears to produce the most repeatable data. There are regional differences in myocardial velocity within the equine ventricles for systole and early diastole. POTENTIAL RELEVANCE: DTI shows potential as a tool for studying regional myocardial movement both in clinical cases suspected of having myocardial dysfunction and in a research setting. In particular, SDTI offers potential as a direct and noninvasive means to study early diastolic function of the equine ventricles.     

Ulcerative dermatitis, thrombocytopenia, and neutropenia in neonatal foals

This report describes transient ulcerative dermatitis, severe thrombocytopenia, and mild neutropenia in 6 foals from 4 mares from geographically diverse regions of the United States. The foals presented at <4 days of age with oral and lingual ulcers, and crusting and erythema around the eyes, muzzle, and perineal, inguinal, axillary, trunk, and neck regions. There was a severe thrombocytopenia (0-30,000 platelets/microL), leukopenia (1900-3200 white blood cells/microL), and mild neutropenia (500-1800 neutrophils/microL). Four of the 6 foals had petechiae and ecchymotic hemorrhages and 3 had bleeding tendencies. Results of examination of a bone marrow biopsy from 1 foal were normal and results of a platelet surface immunoglobulin test in another were negative. Histopathology of the skin in all foals showed subepidermal clefting with subjacent vascular dilation, dermal hemorrhage, and superficial papillary necrosis. The foals were treated supportively with broad-spectrum antibiotics (5/6), corticosteroids (3/6), gastric ulcer prophylaxis (6/6), whole-blood transfusion (4/6), and platelet-rich plasma (1/6). The skin lesions and thrombocytopenia (>50,000 platelets/microL) improved in 2 weeks (4/6). Two foals had a decline in their platelet counts when the steroids were decreased and needed protracted treatment. All foals survived and were healthy as yearlings. Two mares that had 2 affected foals each, upon subsequent pregnancies to different stallions, had healthy foals when an alternate source of colostrum was given. The findings in the cases in this report suggest a possible relationship between colostral antibodies or some other factor in the colostrum and the thrombocytopenia and skin lesions, although further investigation is warranted to confirm or refute this hypothesis.