Canine lymphoma and vector‐borne diseases: Molecular and serological evaluation of a possible complicity

Abstract

Lymphoma is the most common haematological malignancy in dogs and its aetiology is largely unknown. The presence of canine vector‐borne agents (CVBD) in lymphoma tissues has been described and its causative effects questioned. We intended to evaluate the presence and extent of Leishmania infantum, Ehrlichia canis, Anaplasma phagocytophilum and Bartonella henselae infection in dogs with lymphoma. Sixty‐one dogs, living in the Lisbon metropolitan area, with a diagnosis of lymphoma were enrolled. Immunofluorescence assays were used to detect serum IgG's. The presence of DNA from CVBD agents in tumour tissue was assessed by PCR. All dogs tested negative for B. henselae, A. phagocytophilum and E. canis by both serology and PCR. Regarding L. infantum, 8.2% (n = 5) of the dogs had a positive serologic result. L. infantum DNA was detected in two samples of diffuse large B‐cell lymphoma (DLBCL). These results show an increased, but not significant, seropositivity (8.2% vs 7.9%) and molecular detection (3.3% vs 1.2%) for L. infantum in dogs with lymphoma, when compared to the reported canine population in the same geographical area. We could not identify an association between lymphoma and E. canis, A. phagocytophilum, B. henselae or Leishmania infantum infection in the studied population. Nevertheless, further studies, following dogs trough their CVBD disease evolution, are worthwhile and may help clarify a possible role of CVBD agents in lymphomagenesis.

Atypical Lesions in Canine Leishmaniosis: Description of New Cases

“…Also interesting is the relationship reported between Leishmania and tumors, and immunohistochemistry can be a very useful technique. In addition to the possibility of mimicking tumors, as previously described [ 14 ], Leishmania has been detected in tumor cells of certain neoplasms, both in the dog [ 16 , 54 , 55 ] and in humans [ 10 , 13 ]. However, a causal relationship has not yet been demonstrated [ 54 ], although it suggests the ability of Leishmania to spread and infect different types of cells [ 16 ].…”

“…In addition to the possibility of mimicking tumors, as previously described [ 14 ], Leishmania has been detected in tumor cells of certain neoplasms, both in the dog [ 16 , 54 , 55 ] and in humans [ 10 , 13 ]. However, a causal relationship has not yet been demonstrated [ 54 ], although it suggests the ability of Leishmania to spread and infect different types of cells [ 16 ]. It has been suggested that, in endemic areas, tumors should be a differential diagnosis and their possible association is worth investigating.…”

T-cell lymphoma-associated hemophagocytic syndrome in an American Pit Bull Terrier

“…Although it is not clear how chronic inflammation can induce lymphoid proliferation, chronic inflammation has been associated with lymphoma and hemophagocytic syndromes. 1,7,9,16 This association has been documented in both canine and human patients who had lymphoma associated with Ehrlichia , Leishmania , and Borrelia spp. infections.…”

“…14 HLH may occur independent of, or as a part of, a neoplastic process. 7 A 3-y-old, intact female, American Pit Bull Terrier was presented to the Tuskegee University Veterinary Medical Teaching Hospital (TU-VMTH; Tuskegee, AL, USA) with a 2-d history of inappetence and a large subcutaneous mass ventral to the left mandibular ramus, noticed 3 wk prior to presentation. The patient was not current on preventive medications or vaccines.…”

“…infections. 1,6,7 Therefore, it is possible that some LAHS patients may have underlying predispositions that are linked to vector-borne diseases.…”