Serum acute phase protein concentrations in dogs with spirocercosis and their association with esophageal neoplasia – A prospective cohort study

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.

Insights on Spirocerca lupi, the Carcinogenic Dog Nematode

Spirocerca lupi is a nematode transmitted by dung beetles that infects domestic and wild canids in tropical and subtropical regions and is associated with neoplasia. It produces a distinctive pathology with the formation of esophageal nodules classified as inflammatory, preneoplastic, or neoplastic with metastasis to distant organs. Aberrant central nervous system migration of this nematode is also responsible for severe neurological manifestations. Reports of spirocercosis have increased over the last two decades showing spread of this canine helminth in five continents. S. lupi from different geographical locations is genetically distinct with two genotypes, genotype I from Africa, Asia, and Australia, and genotype II from Europe, and recently separated from Spirocerca vulpis, a new species described in red foxes from Europe.

Spirocerca lupi induced oesophageal neoplasia: Predictors of surgical outcome

Canine spirocercosis is caused by the nematode Spirocerca lupi. Migration results in oesophageal fibro-inflammatory nodules that may undergo neoplastic transformation. No studies have assessed pre- or post-surgical prognostic indicators in dogs that undergo intervention for S. lupi induced oesophageal neoplasia. This observational, multi-center study aimed to assess the outcome of dogs with Spirocerca induced sarcoma undergoing endoscopic-guided ablation (n = 12) or surgery (n = 18), and identify prognostic indicators. Parameters evaluated included: age, weight, gender, presenting complaints, duration of clinical signs, complete blood count, serum biochemistry, neoplasia size, placement of percutaneous endoscopically-placed gastrostomy tube, histopathological mitotic indices, days to discharge and chemotherapy administration. Kaplan-Meier survival curves showed no difference in survival between ablation and surgery {(median: 73.5 days (range: 0-1511) vs. 108 days (range: 0-1550), respectively (p = 0.982)}. Reduced survival was documented in patients presenting with weight loss (P = 0.027), hypochromasia (MCHC <33 g/dL, P = 0.023) or leucocytosis (>15 × 10⁹/L, P = 0.017) with a hazard ratio of 2.51 (CI_95% = 1.071-6.018, P = 0.034), 2.71 (CI_95% = 1.10-6.65, P = 0.03) and 4.39 (CI_95%: 1.21-15.97, P = 0.025) respectively. In the dogs surviving more than 21 days, Ht <36% and leucocytosis >15.0 × 10⁹/L at presentation were associated with reduced survival (p = 0.016, p = 0.021 respectively) and hazard ratio of 3.29 (CI_95% = 1.18-9.2, P = 0.023) and 3.81 (CI_95% = 1.15-12.55, P = 0.028) respectively. Intra-intervention-group survival analysis identified increased survival time in dogs receiving chemotherapy, but only within the surgical group (P = 0.02).The hospitalisation time of dogs undergoing ablation (median: 0 days, range: 0-4) was significantly shorter than dogs undergoing surgery (9 days, 1-21) (P < 0.001). In this study, no clear benefit was identified for surgery, thus when ablation is technically possible it should be considered advantageous, as hospitalisation time is significantly shorter. Weight loss, hypochromasia and leucocytosis were identified as long-term prognostic indicators at presentation.

Comparison of acute phase protein and hemodynamic variables in dogs undergoing video-assisted thoracoscopic vs. open pneumonectomy

It has been demonstrated that video-assisted thoracoscopic surgery (VATS) is feasible and safe in humans and animal models. The aim of the present study was to compare the surgical outcome using VATS with that of the standard transthoracic approach for pneumonectomy in dogs, to determine the acute-phase reaction in VATS pneumonectomy, and to analyze the difference between VATS and the standard transthoracic approach. A total of 14 dogs were divided into two groups (n=7); one group underwent VATS and the other group underwent a transthoracic pneumonectomy. Pre-, intra- and post-operative physiologic parameters were monitored, in addition to the blood cell count and serum acute-phase protein (APP) concentrations. The APP and hemodynamic changes between the two approaches were analyzed. Mean surgical time in the VATS group (176.7 min) was significantly longer compared with the open group (132.4 min). All APP concentrations were significantly increased at day 1 postoperation and gradually decreased to preoperative concentrations. The serum concentration of C-reactive protein on day 3 and the white blood cell count on day 1 were significantly higher following surgery in the open group compared with the VATS group (P<0.05). No differences were observed in the physiological parameters between the two groups. Although VATS took longer, animals experienced smaller incision and less stress. Therefore, the VATS approach was satisfactory for total pneumonectomy.

Elimination Half-Lives of Acute Phase Proteins in Rats and Beagle Dogs During Acute Inflammation

The half-lives of typical acute phase proteins in rats and beagle dogs during acute inflammation were investigated. Acute inflammation was induced by injection of turpentine oil in rats and administration of indomethacin in beagle dogs. Serum concentrations of α2-macroglobulin (α2M) and C-reactive protein (CRP) were measured by enzyme-linked immunosorbent assay and α1-acid glycoprotein (AAG) was measured by single radial immunodiffusion. Half-life was calculated as 0.693/elimination rate constant (K). The mean half-lives in the terminal elimination phase of α2M and AAG were 68.1 and 164.8 h, respectively. The half-life of AAG was significantly longer than that of α2M. Mean half-lives in the terminal elimination phase of CRP and AAG were 161.9 and 304.4 h, respectively. The half-life of AAG was significantly longer than that of CRP in beagle dogs. No significant differences in the half-life of AAG were observed between rats and beagle dogs. Furthermore, serum concentrations in the terminal elimination phase could be simulated with the K data acquired in this study.

Systemic Amyloid A Amyloidosis in Island Foxes (Urocyon littoralis): Severity and Risk Factors

Systemic amyloid A (AA) amyloidosis is highly prevalent (34%) in endangered island foxes (Urocyon littoralis) and poses a risk to species recovery. Although elevated serum AA (SAA) from prolonged or recurrent inflammation predisposes to AA amyloidosis, additional risk factors are poorly understood. Here we define the severity of glomerular and medullary renal amyloid and identify risk factors for AA amyloidosis in 321 island foxes necropsied from 1987 through 2010. In affected kidneys, amyloid more commonly accumulated in the medullary interstitium than in the glomeruli (98% [n= 78 of 80] vs 56% [n= 45], respectively;P< .0001), and medullary deposition was more commonly severe (19% [n= 20 of 105]) as compared with glomeruli (7% [n= 7];P= .01). Univariate odds ratios (ORs) of severe renal AA amyloidosis were greater for short- and long-term captive foxes as compared with free-ranging foxes (ORs = 3.2, 3.7, respectively; overall P= .05) and for females as compared with males (OR = 2.9;P= .05). Multivariable logistic regression revealed that independent risk factors for amyloid development were increasing age class (OR = 3.8;P< .0001), San Clemente Island subspecies versus San Nicolas Island subspecies (OR = 5.3;P= .0003), captivity (OR = 5.1;P= .0001), and nephritis (OR = 2.3;P= .01). The increased risk associated with the San Clemente subspecies or captivity suggests roles for genetic as well as exogenous risk factors in the development of AA amyloidosis.

Spirocercosis in dogs in Israel: A retrospective case-control study (2004-2009)

This case-control retrospective study (years 2004-2009) investigated the epidemiological, clinical, and diagnostic test findings of dogs with esophageal spirocercosis (ES) presented to the Hebrew University Veterinary Teaching Hospital (HUVTH) and coproscopy-positive dogs at the Kimron Veterinary Institute (KVI), Israel. It included 133 dogs with ES and 133 negative controls diagnosed at the hospital, and 343 dogs diagnosed at the KVI. The average incidence of ES at the HUVTH was 22.5/year, and the percentage of spirocercosis cases was stable at both institutions (HUVTH, 0.67-1.23%; KVI, 5-8%). Dogs aged > 5 years old had 100-fold likelihood to be infected compared to dogs aged ≤ 1 year of age (P < 0.001). Mean body weight (P = 0.0004), proportion of Retrievers (P = 0.002) and sporting breed dogs (P = 0.006) were higher, while proportion of toy breeds (P = 0.004) was lower in the ES group compared to the control group. The proportion of cases from Greater Tel-Aviv decreased (P = 0.002), while that of those from Judea and Jerusalem increased (P = 0.01) compared to the 1990 s. Spirocercosis occurred in 22 dogs despite past prophylactic avermectin treatment. Vomiting and regurgitation were the most common clinical signs of ES. Coproscopy was S. lupi-positive in 33/60 dogs (55.0%). The median number of esophageal nodules was two (range 1-8), with a median diameter of 3.5 cm (range 1.0-11.0). Malignant esophageal lesion transformation was confirmed in 29 dogs (22%). Despite preventive attempts, spirocercosis has spread in Israel over time, compared to previous findings, raising questions about the efficacy of the currently accepted prophylactic protocol is incompletely effective.