A case report of acute claudication due to vena cava thromboembolism in a dog naturally infected with Leishmania Infantum.

Canine leishmaniosis is a vector-borne disease caused by Leishmania infantum, and clinical manifestations of infection range from absent or severe to fatal and result from immune-mediated mechanisms. In dogs, the most common clinical signs of leishmaniosis include skin lesions and lymphadenomegaly. However, the presence of other nontypical signs has been described, and diagnosing these cases can be challenging. The aim of the present short communication was to describe the impact of the formation of circulating immunocomplexes due to L. infantum in a dog with leishmaniosis affected by a massive venous thrombus of the caudal vena cava and external iliac veins. On admission, the dog presented bilateral cutaneous vasculopathy of the thigh and renal disease due to L. infantum infection. Two weeks after starting anti-Leishmania treatment based on meglumine antimoniate and allopurinol administration, the animal developed acute claudication of the hind limbs with the presence of a thrombus in the caudal vena cava and the external iliac veins and a high level of circulating immunocomplexes detected by enzyme-linked immunosorbent assay. Exacerbation of the humoral immune response, along with deposition of circulating immune complexes in the tissues and the concurrent presence of kidney and liver damage, might have contributed to an imbalance in haemostasis in this patient. Future studies should evaluate and analyse the pathological mechanisms contributing to thrombosis in dogs with leishmaniosis.

Comparative Study of a Novel Lateral Flow Rapid Test with Conventional Serological Test Systems for the Diagnosis of Canine Leishmaniosis in Croatia and Brazil.

Control of canine infections with Leishmania infantum (L. infantum), a major zoonotic disease in Brazil and southern Europe, is becoming increasingly important due to its close proximity to humans, the increasing import of dogs from endemic regions and the impact of climate change on vector spreading. Simple, rapid and reliable diagnostic tests are therefore needed to detect infected dogs. Here, we re-evaluated different serological methods for the diagnosis of canine leishmaniosis (CanL) in Croatia and Brazil. The diagnostic performance of the indirect fluorescent antibody test (IFAT) and the VetLine® Leishmania ELISA (GSD Frankfurt, Germany) was compared with three rKLi8.3-based diagnostic test systems, the rKLi8.3 ELISA (GSD Frankfurt, Germany), the INgezim® Leishma CROM (GSD Madrid, Spain) lateral flow test (LFT) and the VetBlot®Leishmania LineBlot (GSD Frankfurt, Germany). CanL symptomatic dogs were efficiently diagnosed by all tests, except the VetLine® Leishmania ELISA, which is based on whole Leishmania antigens. The advantage of rKLi8.3 was also observed in oligo- and asymptomatic dogs from Brazil and Croatia, although with reduced diagnostic efficiency compared to symptomatic dogs. Similar to IFAT and rKLi8.3 ELISA, the LFT did not cross-react with other common canine pathogens; it showed very high specificity for healthy dogs from endemic regions in both countries and did not react with healthy, vaccinated dogs in Brazil. In conclusion, serodiagnostic tests based on the rKLi8.3 antigens are superior to whole parasite antigens, and the LFT has the advantage of providing a laboratory-independent, rapid and specific diagnosis of CanL.

Canine Leishmaniasis Prevalence in the Slovenian Dog Population.

INTRODUCTION: Leishmaniasis is a life-threatening zoonosis of which dogs are the major reservoir and sandflies are the vectors. Until now, the prevalence of canine leishmaniasis (CanL) in the Slovenian dog population was unknown. MATERIAL AND METHODS: Epidemiological data, eye swabs and blood samples were taken from 465 dogs born in Slovenia and older than one year. Commercial ELISA kits and real-time PCR were used. For ELISA-positive samples, an immunofluorescence antibody test (IFAT) was performed. Descriptive statistics were used to characterise the samples. The one-sample nonparametric chi-square test was used to test whether the categories of a variable were equally distributed. RESULTS: A 59.9% proportion of the recruited dogs had travelled to endemic regions and 62.1% of them had not been protected by insect repellents. Skin symptoms that might be CanL-related were described in 109 of the dogs' histories (23.4%), inappetence and/or weight loss in 25 (5.4%), and anaemia, intermittent fever, and/or lymphadenopathy in 19 (4.1%). At the time of recruitment, all dogs were asymptomatic. All samples were PCR negative, nine (1.9%) were ELISA positive, but none were IFAT positive. Five of the nine ELISA-positive dogs were non-travellers. CONCLUSION: We conclude that the seroprevalence of canine leishmaniasis of 1.9 % in the autochthonous Slovenian dog population may pose a risk of endemic spread of the disease.

Leukocytes and albumin in canine leishmaniasis

Canine Leishmaniasis (CanL) is a multisystemic and chronic inflammatory disease characterized by nonspecific clinical manifestations. In CanL, inflammatory cells and chemical mediators released in response to the parasite play a role in disease development and progression. Alterations on hematological parameters have been documented in CanL. These changes can also be assessed in relation to systemic inflammation caused by this disease. The circulating leukocyte counting, such as neutrophils, as well as the albumin level, are considered direct indicators of an inflammatory host environment. Several studies point to the use of biomarkers on the assistance in diagnosis and prognosis of several canine pathologies. The present study investigated the Neutrophils to Lymphocyte Ratio (NLR), Albumin to Globulin Ratio (AGR), and Neutrophils to Albumin Ratio (NAR) on systemic inflammatory response induced by Canine Leishmaniasis (CanL). For this purpose, adult dogs with confirmed diagnosis to CanL were divided into symptomatic (SD, n = 33) and asymptomatic (AD, n = 20) dogs for L. infantum and control dogs (CD, n = 20). Routine hematological and biochemical parameters were determined in blood samples using a veterinary automatic hematology and biochemical analyzers. Asymptomatic dogs (AD) had a higher number of white blood cells and neutrophils (16.48 ± 4.93; 13.41 ± 3.60, respectively) in relation to symptomatic dogs (SD) (13.54 ± 5.13; 10.42 ± 3.69, respectively) (P = 0.015 and P < 0.0001, respectively). Neutrophils to Lymphocyte Ratio (NLR) was higher in dogs with leishmaniasis (9.45 ± 3.76) than in healthy dogs (3.39 ± 1.19) (P < 0.0001). Serum total proteins (STP) and globulins increased in CanL, while albumin and AGR decreased in CanL, when compared to CD and references values to canine species. Neutrophils to Albumin Ratio (NAR) was higher in AD and SD (5.02 ± 1.14; 4.79 ± 1.07, respectively) when compared to CD (2.36 ± 0.55) (P < 0.0001). As reported in scientific researches, dogs with Leishmaniasis present alterations in circulating cell counts. Based on these data, we decided to expand this information using the NLR as a parameter in an attempt to better clarify the changes in these cells in CanL. We observed that NLR was increased on CanL in relation to healthy dogs, which could be a consequence of relative neutrophilia rather than lymphopenia. Neutrophils to Lymphocyte Ratio (NLR) is a biomarker that conveys information about inflammatory conditions. An elevated NLR can reflect an upregulated innate immune response, since neutrophils are effector cells of innate immunity and are involved in several acute and chronic inflammatory processes. Albumin is an acute phase protein that is considered an immune-inflammatory biomarker, which can be found reduced systemically in progressive inflammatory response. Serum total proteins (STP) and globulins were increased in CanL. These data are already well documented in CanL, which serum globulins are mainly associated with the increase of acute phase proteins, cytokines, and increase of specific antibodies to Leishmania infantum. Our results showed neutrophilia with hypoalbuminemia in CanL. So, in an attempt to assess the relationship of these two available markers, we used NAR calculation in order to evaluate the changes induced by CanL. In this study NAR was higher in CanL when compared to control dogs. Thus, our data indicate that NLR and NAR could be used as biomarkers in veterinary medical clinics in order to assess inflammatory profile in CanL, mainly in asymptomatic dogs. These parameters obtained from routine blood tests might be useful as cost-effective, easily accessible and helpful markers in order to distinguish the inflammatory response intensity in CanL.(AU)

Allopurinol therapy provides long term clinical improvement, but additional immunotherapy is required for sustained parasite clearance, in L. infantum-infected dogs.

There is little evidence that current control strategies for canine leishmaniosis (CanL), the veterinary disease caused by L. infantum infection, are having a positive impact. This is of critical importance because dogs are a primary reservoir for L. infantum and a significant source of parasite transmission to humans. Drugs intended primarily for human use are prohibited for the treatment of CanL because of concerns over the propagation of resistant parasites. Although allopurinol effectively decreases parasite burden in CanL the treatment needs to be maintained for life. We hypothesized that during the allopurinol-induced parasite reduction dogs may become capable of developing a more robust immune response that may permit more effective control of parasites. To test this, we investigated the clinical and parasitological impact of short-term treatment with allopurinol, either alone or in combination with a defined subunit vaccine, on dogs naturally infected with L. infantum. A total of 28 dogs were distributed as follows: untreated; oral allopurinol alone (20 mg/kg, once each day for 90 days); or allopurinol with immunization with the Leish-F2 antigen formulated with the Toll-like receptor (TLR) 4 agonist Second generation Lipid Adjuvant (SLA) in stable emulsion (SE; SLA-SE). Dogs that did not receive treatment had a progressive decline in their clinical condition and an increase in their infection levels, while treatment with allopurinol alone alleviated the clinical symptoms of CanL but did not generate sustained reduction in parasites. Concomitant immunization with Leish-F2 + SLA-SE, however, improved clinical condition while also providing long-term clearance of L. infantum from lymphoid tissues and systemic organs. These results have important implications for both the management of CanL and for limiting L. infantum transmission to humans.

Improving the serodiagnosis of canine Leishmania infantum infection in geographical areas of Brazil with different disease prevalence.

Serodiagnosis of Leishmania infantum infection in dogs relies on the detection of antibodies against leishmanial crude extracts or parasitic defined antigens. The expansion of canine leishmaniasis from geographical areas of Brazil in which the infection is endemic to regions in which the disease is emerging is occurring. This fact makes necessary the analysis of the serodiagnostic capabilities of different leishmanial preparations in distinct geographical locations. In this article sera from dogs infected with Leishmania and showing the clinical form of the disease, were collected in three distinct Brazilian States and were tested against soluble leishmanial antigens or seven parasite individual antigens produced as recombinant proteins. We show that the recognition of soluble leishmanial antigens by sera from these animals was influenced by the geographical location of the infected dogs. Efficacy of the diagnosis based on this crude parasite preparation was higher in newly endemic regions when compared with areas of high disease endemicity. We also show that the use of three of the recombinant proteins, namely parasite surface kinetoplastid membrane protein of 11 kDa (KMP-11), and two members of the P protein family (P2a and P0), can improve the degree of sensitivity without adversely affecting the specificity of the diagnostic assays for canine leishmaniasis, independently of the geographical area of residence. In addition, sera from dogs clinically healthy but infected were also assayed with some of the antigen preparations. We demonstrate that the use of these proteins can help to the serodiagnosis of Leishmania infected animals with subclinical infections. Finally, we propose a diagnostic protocol using a combination of KMP-11, P2a y P0, together with total leishmanial extracts.