Periocular thelaziasis presenting as an orbital mass - a case report.

Thelazia callipaeda is a rare parasitic infestation caused by spiruroid nematode of the genus Thelazia. We report a case of a 74-year-old gentleman who presented with a painless swelling of left lower lid since 15 days. Examination revealed a firm mobile mass along the inferior orbital rim. Magnetic Resonance Imaging showed a well-defined preseptal cystic lesion and Ultrasound screening revealed multiple mobile worms within. Patient underwent cyst excision in toto under local anesthesia. Four long refractile worms were isolated from within the cyst cavity. Species identification confirmed the parasite as Thelazia callipaeda. Periocular thelaziasis usually presents as free floating worms in the conjunctival sac, anterior chamber or vitreous cavity. It is important to be aware of this rare entity which should be considered as a differential diagnosis in endemic areas.

Comparative imaging of European eels (Anguilla anguilla) for the evaluation of swimbladder nematode (Anguillicoloides crassus) infestation.

This study compares diagnostic imaging tools in detecting the parasitic swimbladder nematode Anguillicoloides crassus in Anguilla anguilla (L.) and focuses on ultrasound in an attempt to develop a non-destructive, field diagnostic test. Ultrasound use could allow the parasite to be diagnosed without decreasing the number of critically endangered European eels through post-mortem. In the preliminary study, eels were examined with computed radiography, computed tomography, magnetic resonance imaging, 14 MHz high-end ultrasound and 5 MHz low-end portable ultrasound, and the results were compared with post-mortem findings. This ultrasound scanning technique did not produce any promising results. A second batch of eels was examined using the same high-end and low-end ultrasounds, but employing a different scanning technique and comparing the results with post-mortem. This second study, scanning along the midline from below, allowed for the detection of anomalies associated with moderately infected animals. None of the eels used in this study were severely infected; thus, no conclusions can be made regarding the use of ultrasound in those animals. Overall, it was found that none of the techniques were useful in diagnosing mildly infected individuals; therefore, no single diagnostic imaging tool is sensitive enough to replace post-mortem for definite diagnosis.

Triple phase dynamic computed tomographic perfusion characteristics of spirocercosis induced esophageal nodules in non-neoplastic versus neoplastic canine cases.

Neoplastic transformation of Spirocerca lupi induced esophageal nodules carries a poor prognosis. Clinical, clinicopathological, endoscopic, and radiographic characteristics may be indicative of neoplastic transformation but variable sensitivity and specificity of these parameters makes their use questionable. We hypothesized that CT would be a better diagnostic modality to discriminate between non-neoplastic and neoplastic nodules. In this prospective study of 38 dogs, the appearance and perfusion characteristics of confirmed spirocercosis-induced neoplastic and non-neoplastic esophageal nodules were described using survey CT and triple phase dynamic CT angiography (CTA). Pre- and post-contrast early arterial, late arterial, and venous CTA images were evaluated. Non-neoplastic nodules were smooth and nonmineralized with a higher proportion of hypoattenuating necropurulent cavities compared to neoplastic nodules that had a more irregular surface, with 93% having mineralized foci and rarely any hypoattenuating pockets. Non-neoplastic nodules were significantly more perfused than neoplastic nodules with the difference being up to 23 Hounsfield units. The difference was most marked in the early and late arterial phases (P = 0.0005 and 0.00005, respectively). Ratios of the normal esophagus adjacent to the neoplastic and non-neoplastic nodules did not differ significantly from each other. Perfusion findings demonstrated relative hypoperfusion of the esophageal sarcomas. Findings from the current study indicated that CT characteristics of relative postcontrast hypoperfusion, combined with nodule irregularity and mineralization warrant a high level of concern for neoplastic transformation in canine spirocercosis-induced esophageal nodules.

Ultrasonography is insensitive but specific for detecting aortic wall abnormalities in dogs infected with Spirocerca lupi.

BACKGROUND: Spirocercosis is caused by the nematode Spirocerca lupi (S lupi). The disease mainly affects dogs and is typically diagnosed by oesophagoscopy or faecal examination; however, these diagnostic tests may deliver false negative results during the migration phase of the nematode. The aim of the present prospective study was to evaluate whether ultrasonography could detect abnormalities in the abdominal aorta, celiac artery, and gastric wall structure as a diagnostic aid to detect S lupi infection in dogs. METHODS: Oesophagoscopy and a focused abdominal ultrasound scan were performed in 40 dogs that presented to the Koret School of Veterinary Medicine Teaching Hospital, Hebrew University of Jerusalem, with gastrointestinal complaints. Ultrasonography scan findings of 20 dogs with oesophageal nodules, indicating S lupi infection (study group), were compared with those of 20 control dogs. RESULTS: Vascular wall irregularity was significantly more common in the study group than in the control group (9/20 v 1/20, respectively; P=0.008). CONCLUSION: Ultrasonographic evaluation of the abdominal aorta, celiac artery, and gastric wall structure is not a sensitive diagnostic marker for spirocercosis in dogs. However, the presence of vascular wall irregularity of the abdominal aorta or celiac artery might indicate S lupi migration.

Threat of exotic worms in dogs imported from Romania.

More and more dogs are legally entering the UK from overseas, bringing with them the risk of importing unusual parasites, some of which are zoonotic. Here, Ian Wright and colleagues describe three cases of parasitic worms found in Romanian dogs.

Radiography for the diagnosis of spirocercosis in apparently healthy dogs, St. Kitts, West Indies.

Fifty apparently healthy island dogs presenting to the Ross University School of Veterinary Medicine (RUSVM), St. Kitts, West Indies for neutering were used in this prospective study. Twelve of the dogs (24%) were diagnosed with spirocercosis based on a positive fecal analysis and characteristic lesions seen during esophagoscopy. Routine thoracic survey radiographs revealed changes previously reported with spirocercosis in 10/12 (sensitivity=83%) infected dogs, but in none of the uninfected dogs (38/38; specificity=100%). The most common radiographic changes were an increased fluid density within the caudal dorsal thorax on the lateral view and a widening and/or bulging of the caudal mediastinum on the dorsoventral view. After oral administration of barium sulfate, barium retention or a tortuous esophagus was visible in all infected dogs (12/12; sensitivity 100%) and in one uninfected dog (1/38; specificity 97%). The results show spirocercosis is common on St. Kitts and that radiographs are as dependable as fecal analysis and/or endoscopy in diagnosing the condition.

Ultrasound biomicroscopy in the diagnosis and management of intraocular gnathostomiasis.

PURPOSE: To describe the use of ultrasound biomicroscopy in the identification of an intraocular nematode in a case of suspected nematode-induced uveitis DESIGN: Observational case report. METHOD: UBM was performed under topical anesthesia in a patient with acute painful uveitis suspected to result from an intraocular nematode. Clinical examination did not reveal the nematode. RESULTS: Over a 6-minute time span, serial UBM examinations revealed the nematode to move from the iris root into the posterior chamber through the zonules. Subsequently, it was seen adhering to the cornea and could be removed surgically, resulting in symptom relief. CONCLUSION: UBM is a useful tool in diagnosis and management of parasitic uveitis.

Evaluation of doramectin for the treatment of experimental canine spirocercosis.

The nematode Spirocerca lupi is primarily a parasite of dogs, which causes typical lesions of esophageal nodular granulomas, aortic aneurysms and spondylitis. In order to evaluate the therapeutic effect of doramectin on experimental canine spirocercosis, seven beagle dogs experimentally infected with 40 infectious S. lupi larvae (L(3)) were treated with doramectin. Treatment was commenced following endoscopic visualization of esophageal granulomas, and typical S. lupi eggs were detected in the feces. The treatment protocol included six treatments of doramectin (400 microg/kg subcutaneously) at 2 weeks intervals, followed by monthly injections until the disappearance of the esophageal granulomas or the end of the study (768 days post-inoculation). Eggs could not be found on fecal examinations 3-10 days after the first or second doramectin treatment. In addition, a gradual decrease in size of granulomas was noticed in all seven dogs during the course of the study. Esophageal granulomas had completely resolved in six of the seven dogs between day 35 and day 544 post-initial doramectin treatment, by day 35 in one dog (after three treatments), by day 43 in two dogs (after four treatments), by day 98 in one dog (after seven treatments), by day 460 in one dog (after 18 treatments) and by day 544 in another dog (after 21 treatments). In one dog, remnants of S. lupi granulomas could still be seen 544 days post-initiation of treatment with doramectin. Multiple subcutaneous injections of doramectin (400 microg/kg) were shown to be effective and safe in the treatment of canine spirocercosis.

Radiodiagnostic method for studying swimbladder inflammation caused by Anguillicola crassus (Nematoda: Dracunculoidea).

The nematode Anguillicola crassus appeared in Europe about 15 yr ago, and has subsequently become recognised as a cause of major pathological lesions in the swimbladder of the European eel Anguilla anguilla. The radiographic method reported in this paper showed be a useful complement to diagnostic methods that have so far been based exclusively on fish dissection. Using this method, the infection of the swimbladder and the severity of its pathological changes can be assessed in a reliable manner without causing damage to the fish. By analysing radiographs of 45 eels from Lake Balaton, 5 stages of swimbladder lesions were distinguished. The method enables the examiner to draw conclusions on the air, worm and exudate content of the swimbladder; however, data on thickening of the swimbladder wall can be obtained only indirectly. The radiograph also provides information on the air and worm content of the pneumatic duct. Results obtained by radiography showed good agreement with dissection findings. Radiographic results are compared with pathological findings obtained from fish dissections separately for each severity grade of infection.

Spirocerca lupi-associated vertebral changes: a radiologic-pathologic study.

Spirocerca lupi causes a caudal esophageal mass in dogs which may be accompanied by aortic changes and caudal thoracic spondylitis. Previous literature hypothesized that the spondylitis was caused by either aberrant larval migration or was secondary to the inflammation caused by the aortic migration. The current study aimed to evaluate these hypotheses. Ten dogs of various breeds and ages with radiographic evidence of spondylitis, which were necropsied, had the affected vertebrae removed and prepared for light and transmission electron microscopy examination. Transverse and sagittal sections of the ventral vertebrae were taken from 27 spondylitis and 8 spondylosis deformans lesions as well as from 8 normal vertebrae. Early spondylitis changes were characterized by periosteal woven new bone covered by hyperplastic periosteum with some involvement of the ventral longitudinal ligament. More mature lesions were characterized by nodules of denser trabecular bone and cartilage, also covered by hyperplastic periosteum and involved the ventral longitudinal ligament. It was difficult to distinguish the spondylitis and spondylosis deformans new bone. Inflammation was seen in five spondylitis cases (edema, lymphocytes, plasma cells, eosinophils and fibrin fibers). Spirocerca eggs were seen in one histologic section. This study shows that inflammation is mild and inconsistent in spirocercosis-induced spondylitis and that aberrant migration of the larvae or adults did not appear to be a predominant cause. Inflammatory mediators or osteoproliferative growth factors, which may be related to the primary esophageal lesion or to the worm itself, could be involved. This requires further investigation.

Pneumoesophagography and the appearance of masses in the caudal portion of the esophagus in dogs with spirocercosis.

OBJECTIVE: To determine the usefulness of pneumoesophagography, compared with that of survey radiography, for characterization of esophageal pathological changes in dogs with endoscopically confirmed intraluminal Spirocerca lupi nodules in the caudal portion of the esophagus. DESIGN: Diagnostic test evaluation. ANIMALS: 30 dogs with endoscopically confirmed spirocercosis. PROCEDURES: Dorsoventral (DV) and right lateral recumbent (RLR) thoracic survey radiographs were obtained for each dog. Endoscopy was subsequently performed, the esophagus was inflated with air, and left lateral recumbent, RLR, DV, and ventrodorsal thoracic radiographs were obtained. The amount of esophageal and gastric distention was recorded. Visibility, location, and surface characteristics of lesions and total length of esophageal involvement were recorded independently for each radiograph and modality and compared with each other. RESULTS: Survey DV radiographs were more reliable than survey RLR radiographs for detecting caudal esophageal pathological changes. Lateral pneumoesophagograms showed more esophageal air and had more visible nodules than did their orthogonal counterparts. Right lateral recumbent pneumoesophagograms allowed for evaluation of the air-filled stomach, particularly the cardiac portion, for additional pathological changes. Pneumoesophagography allowed the mural position (47% located dorsally) and surface characteristics of Spirocerca nodules to be determined. Six of 9 dogs with confirmed malignant disease had an irregular nodule surface suggestive of neoplastic transformation. CONCLUSIONS AND CLINICAL RELEVANCE: Pneumoesophagography was easily performed in dogs with spirocercosis and showed promise as a cost-effective and safe initial diagnostic procedure for further evaluation and characterization of suspected caudal esophageal lesions.

The effect of positioning on the radiographic appearance of caudodorsal mediastinal masses in the dog.

In this prospective study, the effect of thoracic positioning on the visibility and size of caudal esophageal masses caused by spirocercosis was investigated. Dorsoventral (DV), ventrodorsal (VD) as well as left lateral recumbent (LLR) and right lateral recumbent (RLR) thoracic radiographs of 28 dogs, diagnosed endoscopically with spirocercosis, were evaluated. The radiographic findings were compared with those of esophageal endoscopy. Masses were seen equally well in left vs. right recumbency as well as in DV vs. VD positions but in DV/VD views 86% of masses were detected whereas in lateral views only 50% of masses were identified. In spirocercosis-endemic areas DV and RLR views are advised as they also allow for better visualization of descending aorta aneurysms and to avoid interpreting the potentially normally visible esophagus in LLR in large dogs as a mass.

Medullary gnathostomiasis in a white patient: use of immunodiagnosis and magnetic resonance imaging.

A 48-year-old French diplomat presented with a sensory-motor paraparesis of rapid onset, leading to paraplegia. Successive magnetic resonance image scans showed lesions of the thoracic spinal cord that were at different levels from one examination to the next. Specific anti-gnathostome antibodies were detected by means of enzyme-linked immunosorbent assay and Western blot test in both plasma and cerebrospinal fluid. Albendazole treatment prevented disease progression, but only partial regression of the neurologic symptoms was obtained.

Radiographic and computed tomographic changes and clinical presentation of spirocercosis in the dog.

A retrospective study of 39 dogs with spirocercosis is described, emphasizing radiographic and computed tomographic aspects and clinical presentation. Dogs were classified as complicated or uncomplicated, both clinically and radiographically. Besides the expected upper gastrointestinal signs, a high incidence of respiratory (77%) and locomotor (23%) complications were present. All dogs had thoracic radiographs. Esophageal masses were radiographically classified as typical or atypical according to their location. Twenty-seven dogs had a typical caudal esophageal mass. Six dogs had a mass atypically located in the hilar region. These masses were smaller and more difficult to visualize radiographically. The remaining 6 dogs did not have a radiographically detectable esophageal mass. Radiology as an initial diagnostic tool was effective in detecting and localizing the mass and to detect early respiratory abnormalities such as pleuritis, mediastinitis, pneumonia, and bronchial displacement. Endoscopy was the modality of choice to confirm antemortem esophageal masses. In dogs where the mass filled the whole esophageal lumen, endoscopy failed to give essential information necessary for surgical excision of neoplastic masses, such as the extent of esophageal wall attachment. Caudal esophageal sphincter involvement was difficult to determine endoscopically with large caudal esophageal masses. Computed tomography was performed on 3 dogs and did not address the latter problems completely, but was found to be a sensitive tool to detect focal aortic mineralization and early spondylitis, both typical for the disease, and essential in the diagnosis of non- or extramural esophageal abnormalities.