Aberrant Mesenteric Migration of Spirocerca lupi Larvae Causing Necrotizing Eosinophilic Arteritis, Thrombosis, and Intestinal Infarction in Dogs

Aberrant migration of Spirocerca lupi to the spinal cord in dogs: Association of clinical signs, CSF analysis, preventive treatment, and outcome

Spirocerca lupi is a nematode typically targeting the esophageal wall but may also migrate to the spinal cord. This study aimed to characterize the clinical presentation, cerebrospinal fluid (CSF) findings, prognostic factors, and outcomes of dogs with spinal S. lupi (SSL) aberrant migration, and to evaluate prophylactic treatment efficacy. Medical records from 2016 to 2022 were reviewed, including 284 study and 280 control dogs. Complete recovery occurred in 130/284 dogs (46 %) at 1 month, and in 214/284 dogs (75 %) at 3 months and was associated with the clinical grade at presentation (P < 0.001). Of the 162 non-ambulatory dogs, 59 % became ambulatory at 1 month, and 79 % at 3 months. Dogs with urinary incontinence were less likely to fully recover (P = 0.04). Protein CSF concentration was lower at presentation in dogs who completely recovered at 1 month and 3 months (344 mg/dL [15-1297] vs. 732 mg/dL [34-1291], P = 0.006, and 366 mg/dL [15-1297] vs. 769 mg/dL [83-1262], P = 0.025, respectively). A higher proportion of control dogs received prophylactic treatment compared to the SSL group (216/280 [77 %] vs. 168/284 [59 %], respectively, P < 0.001, OR 0.43, CI 0.30-0.62) however, prophylactic treatment did not significantly impact recovery rates. Our findings suggest that SSL is associated with a favorable prognosis; however, full recovery may take several months, and dogs presenting with urinary incontinence and higher neurological severity grades are less likely to recover. Finally, our findings suggest that prophylactic treatment against S. lupi may have a protective effect against SSL and is therefore recommended in endemic regions.

Corrugated intimal surface of the ovine aorta: when physiology resembles pathology

The aortic lumen in healthy animals is characterized by a smooth, whitish surface, but sheep have macroscopic corrugation of the intimal surface in the thoracic aorta (TA). Our aim was to determine if this finding was pathological or physiological. Thirteen sheep aortas were included in this work together with aortas from cattle (n = 3), a goat (n = 1), horses (n = 4), dogs (n = 2), rabbits (n = 2) and a pig (n = 1). A corrugated intimal surface in the TA was seen in all the sheep and the goat but was less evident in the cattle. Histologically, in sheep the TA intimal surface was seen to have multifocal bulging areas that protruded into the lumen. The outer half of the tunica media had numerous, randomly distributed muscle islands that disrupted the arrangement of the elastic lamella, displacing them towards the lumen. We conclude that the intimal corrugation of the TA in sheep is physiological and must not be misinterpreted as pathological.

Cancerogenic parasites in veterinary medicine: a narrative literature review

Parasite infection is one of the many environmental factors that can significantly contribute to carcinogenesis and is already known to be associated with a variety of malignancies in both human and veterinary medicine. However, the actual number of cancerogenic parasites and their relationship to tumor development is far from being fully understood, especially in veterinary medicine. Thus, the aim of this review is to investigate parasite-related cancers in domestic and wild animals and their burden in veterinary oncology. Spontaneous neoplasia with ascertained or putative parasite etiology in domestic and wild animals will be reviewed, and the multifarious mechanisms of protozoan and metazoan cancer induction will be discussed.

Subcutaneous spirocercosis in a dog from Costa Rica and first molecular confirmation of Spirocerca lupi in Central America

Spirocerca lupi is the etiological agent of spirocercosis in canids from tropics and subtropics in the world. This parasite can lead to life threatening complications, including the formation of fibro and osteosarcomas. A 5-year-old crossbreed Maltese dog from Costa Rica was presented to a veterinary clinic with two nodules in the subcutaneous tissues of the cervical region. One of the nodules resolved with intramuscular antibiotic and anti-inflammatory treatment. However, the other nodule persisted and became purulent. The content of the nodule was excised releasing two coiled 3-cm reddish worms. Identity of the specimens was confirmed by amplifying an 850 bp fragment of the 18S rDNA. The obtained sequence showed 99.96% similarities with S. lupi from Hungary. The present study highlights the need of veterinary clinicians' awareness towards nematode aberrant migrations, and the require of molecular studies to gain insight into the parasite's evolutionary history.

CHARACTERIZATION OF LESIONS INDUCED BY SPIROCERCA VULPIS (SPIRURIDAE: SPIROCERCIDAE) IN RED FOXES (VULPES VULPES)

Spirocerca lupi infection in dogs (Canis domesticus) is associated with esophageal lesions that may evolve to a neoplastic stage in the form of esophageal sarcoma. In the red fox (Vulpes vulpes) infected with the closely related Spirocerca vulpis, similar lesions may occur in the stomach, but neoplastic forms have not been reported. We characterize Spirocerca vulpis-induced lesions in the fox, using pathology and immunohistochemical (IHC) techniques. Seventy-one out of 163 Spirocerca vulpis-positive red foxes were selected and subjected to histopathological study. Lesions were classified as patchy or diffuse. Ten patchy and 10 diffuse lesion samples were studied using three IHC markers (CD68, CD3, and CD79α for macrophages, T lymphocytes, and B lymphocytes, respectively) and H&E stain for neutrophils and eosinophils. Intensity of necrosis, hemorrhages, and the presence of collagen was also analyzed. Of the S. vulpis-positive red foxes, 96.9% had S. vulpis nodules localized in the gastric area (wall and/or omentum), and 3.1% had nodules in the small intestine. All the samples had a moderate to severe lymphoplasmacytic infiltrate. Mild eosinophil infiltration was observed in both types of lesions, while neutrophil infiltration was significatively higher in the patchy than in the diffuse lesions. Fibrosis with mature collagen fibers was also predominant in the patchy lesions along with the presence of T lymphocytes and macrophages. Both the patchy and diffuse patterns had very few B lymphocytes. These findings suggest that the diffuse form is an earlier stage of the lesion, which eventually evolves into patchy forms. Neoplastic forms were not seen. Although more studies are necessary, this study describes the lesions, characterizes the inflammatory infiltrates, and establishes a possible evolution of the different pathological forms of S. vulpis infection in the red fox.

Spirocerca lupi Proteomics and Its Role in Cancer Development: An Overview of Spirocercosis-Induced Sarcomas and Revision of Helminth-Induced Carcinomas

Spirocerca lupi is a parasitic nematode of canids that induces a myriad of clinical manifestations in its host and, in 25% of infections, leads to the formation of sarcomas. The description of the protein composition of the excretory and secretory products (Sl-ESP) of S. lupi has shed light on its possible interactions with the host environment, including migration within the host and mechanisms of immunomodulation. Despite this, the process by which S. lupi induces cancer in the dog remains poorly understood, and some hypotheses have arisen regarding these possible mechanisms. In this review, we discuss the role of specific ESP from the carcinogenic helminths Clonorchis sinensis, Opisthorchis viverrini and Schistosoma haematobium in inducing chronic inflammation and cancer in their host’s tissues. The parasitic worms Taenia solium, Echinococcus granulosus, Heterakis gallinarum, Trichuris muris and Strongyloides stercoralis, which have less-characterized mechanisms of cancer induction, are also analyzed. Based on the pathological findings in spirocercosis and the mechanisms by which other parasitic helminths induce cancer, we propose that the sustained inflammatory response in the dog´s tissues produced in response to the release of Sl-ESP homologous to those of other carcinogenic worms may lead to the malignant process in infected dogs.