Guidelines for treatment of leishmaniasis in dogs

Treatment of Leishmania infantum Infections in Dogs

Dogs are reservoir hosts of the zoonotic parasite Leishmania infantum, the causative agent of canine leishmaniosis. Antiparasitic drugs that are commonly used in dogs include allopurinol, miltefosine, and meglumine antimoniate. Treatment success is characterized by an improvement of disease signs, reduction in parasite load, as well as prevention of relapse. However, despite treatment, infections in dogs can usually not be cleared and often lead to (recurrent) signs of disease. Since most of the drugs used in dogs are also applied in human medicine, the prevention of treatment-induced drug-resistant Leishmania strains is a major one-health concern. This review article provides an overview of current treatment options for Leishmania-infected dogs with allopurinol, meglumine antimoniate, and miltefosine, related adverse effects, and drug resistance potential.

Clinical, histopathological and parasitological follow-up of dogs naturally infected by Leishmania infantum before and after miltefosine treatment and associated therapies

In Brazil, Visceral Leishmaniases is caused by Leishmania infantum, and domestic dogs are the main reservoirs in its urban transmission cycle. As an alternative to euthanizing dogs, miltefosine has been used to treat canine visceral leishmaniasis since 2016. In this study, we have assessed the efficacy of miltefosine for treating canine visceral leishmaniasis in a new endemic area through follow-up of naturally infected dogs was evaluated. The clinical, parasitological, and histopathological characteristics of 21 dogs naturally infected with L. infantum were assessed at three time points: on the day before initiating miltefosine treatment (T0), immediately after treatment completion (T1), and 6 months after treatment completion (T2). Three dogs were treated exclusively with miltefosine, while eighteen received combination therapy with miltefosine with other treatments such as allopurinol, domperidone and immunotherapy. Skin biopsies were obtained from the abdomen to assess inflammatory responses and to quantify parasite loads using qPCR. The parasites were isolated using aspirates acquired from popliteal lymph nodes. Molecular and parasitological analyses confirmed the presence of L. infantum in all dogs, validating the effectiveness of skin and lymph node samples for diagnosis. The clinical conditions of the infected animals were improved and the skin parasite load decreased after treatment, even when distinct combination therapies were performed. The histopathological assessment revealed a miltefosine-induced reduction in the inflammatory response and a decrease in amastigotes number. Furthermore, a positive correlation was established between the reduction in parasite load and the enhancement of clinical scoring, as well as a reduction in the skin inflammatory response. Our findings suggest that miltefosine-based combination therapies reduce skin parasite load and improve clinical outcomes, while the dogs treated with miltefosine alone showed increased parasitic load and worsened clinical staging at T2. Considering this data belonging to a recent transmission area, treatment strategy suggests effective in controlling canine visceral leishmaniasis.

Is pancreatitis associated with meglumine antimoniate treatment for canine leishmaniosis? A multicentric prospective study

BACKGROUND

Meglumine antimoniate is used to treat canine leishmaniosis. In humans, it has been associated with pancreatitis. Although a few case reports have described acute pancreatitis secondary to antimonial treatment in dogs, some studies have concluded that pancreatitis is not an adverse effect of this medication. The objective was to evaluate whether treatment with meglumine antimoniate could induce pancreatitis in dogs with leishmaniosis, on the basis of clinical signs, canine serum specific quantitative pancreatic lipase immunoreactivity (cPLI) concentration, and ultrasonographic abnormalities.

METHODS

A prospective, observational, longitudinal, and multicentric study was conducted from April 2021 through February 2023.

RESULTS

A total of 33 dogs with leishmaniosis were included and classified into LeishVet clinical stages; 13 (39.4%) were included in stage II, 11 (33.3%) in stage III, and 9 in stage IV (27.3%). and 14 (42.4%) developed pancreatitis, 10 during treatment with meglumine antimoniate, and 4 at the end of the treatment. Advanced LeishVet clinical stage was statistically associated with development of pancreatitis. In addition, nine dogs received prednisone at the beginning of treatment, but it was not statistically associated with the prevention of pancreatitis.

CONCLUSIONS

Meglumine antimoniate remains the first line leishmanicidal treatment option for canine leishmaniosis, but it appears to induce pancreatitis in a significant percentage of dogs. Monitoring serum cPLI levels and performing an abdominal ultrasound should be considered when pancreatitis-associated clinical signs are observed, or when there is a high suspicion of circulating immune complexes in dogs with advanced LeishVet clinical stage.

Efficacy of a combination of nucleotides and lactoferrin in maintaining stable or improving the clinical picture and laboratory findings of leishmaniotic dogs: A randomized controlled study

This prospective, randomized, controlled, therapeutic study aimed to evaluate the efficacy of a product containing nucleotides and lactoferrin in maintaining or improving the clinical picture and laboratory findings of canine leishmaniosis (CanL). The safety and tolerance of this combination were also assessed. Forty Leishmania infantum-seropositive dogs, not requiring leishmanicidal and/or leishmaniostatic treatment, were enrolled in the study and randomized into treatment (TG) and placebo (CG) groups. Products A (containing nucleotides and lactoferrin) and B (placebo) were blindly administered to TG and CG, respectively, as palatable tablets at a rate of 1 tablet per 10 kg of weight once every 24 h for 6 months. Following inclusion (T0), dogs were followed up after 3 (T90) and 6 (T180) months. At each time point, for all animals enrolled physical examination and laboratory tests (complete blood count, biochemical panel including C-reactive protein [CRP] and ferritin, and serum protein electrophoresis) were performed. The immunofluorescence antibody test to detect antibodies for L. infantum (T0, T180), Ehrlichia canis (T0, T90, and T180), and Anaplasma phagocytophilum (T0, T90, and T180) was executed. A CanL-dedicated clinical score, using a validated scale from 0 (i.e., absence of clinical signs) to 19, was assigned. Four dogs (n=2 in TG, n=2 in CG) did not complete the study. No statistically significant differences in CanL clinical score were observed between CG and TG at T0, T90 and T180. Both TG and CG showed significant variations in anti-L. infantum antibody titres (p=0.0001 and p=0.004, respectively). In TG, antibody titres decreased in 77.8 %, increased in 5.5 %, and remained stable in 16.7 % of dogs, while in CG, decreased in 27.8 %, increased in 50 %, and remained stable in 22.2 % of dogs. During the study, CRP and ferritin remained stable in TG and significantly increased in CG. At T180, 9 out of 18 dogs (50 %) enrolled in the CG, and 1 out of 18 (5.6 %) enrolled in the TG, developed an active form of leishmaniosis. No side effects were reported in any patient included. In conclusion, a 6-month oral administration of a supplement containing nucleotides and lactoferrin was effective in maintaining a stable clinical score, improving antibody titres and potentially reducing the progression from non-active to active forms in L. infatum seropositive dogs. Furthermore, the product was well-tolerated, easy to administer, and free of side effects.

New immunomodulatory treatment protocol for canine leishmaniosis reduces parasitemia and proteinuria

The current standard treatment for canine leishmaniosis (CanL), N-methylglucamine antimoniate (MGA) given with allopurinol, is not fully effective and may cause adverse effects and drug resistance. In vitro and in vivo studies have shown that nucleotides, administered alone or with AHCC, offer benefits in the treatment of CanL. This study examines the effects of a new immunomodulatory treatment protocol in which dietary nucleotides and AHCC are added to the recommended standard treatment. Out of 160 sick dogs with naturally occurring clinical leishmaniosis recruited, 97 were randomized to a supplement (n = 47) or control (n = 50) group. All dogs received an initial 28-day course of MGA and 365-day course of allopurinol. From day 0 to day 730, dogs in the control group additionally received a placebo, while dogs in the supplement group received Impromune (Bioiberica S.A.U., Esplugues de Llobregat, Spain), an oral supplement providing 32 mg/kg nucleotides and 17 mg/kg AHCC daily. After 2 years, five dogs had relapsed in the supplement group (18.5%) while seven did so in the control group (22.6%). Over time, animals in both groups showed significant improvements in body weight, LeishVet clinical stage, clinical score, and anti-Leishmania antibodies. Adding the supplement to the standard protocol resulted in further significant improvements, namely in reducing the parasite load and urinary protein/creatinine ratio, improving IRIS stage, lowering serum creatinine levels on day 30, deceasing urine turbidity on day 365, and improving weight gain on day 545. The daily intake of the supplement over two years proved safe and well tolerated. Our study confirms the efficacy of the recommended standard treatment for CanL, but also reveals that by adding Impromune additional benefits are obtained, especially reduced parasitemia and improved renal function.

Trends and Gaps in the Scientific Literature about the Effects of Nutritional Supplements on Canine Leishmaniosis

In canine leishmaniosis (CanL), complex interactions between the parasites and the immunological background of the host influence the clinical presentation and evolution of infection and disease. Therefore, the potential use of nutraceuticals as immunomodulatory agents becomes of considerable interest. Some biological principles, mainly derived from plants and referred to as plant-derived nutraceuticals, are considered as supplementation for Leishmania spp. infection. This study provides a systematic review regarding the use of nutraceuticals as a treatment using a text mining (TM) and topic analysis (TA) approach to identify dominant topics of nutritional supplements in leishmaniosis-based research, summarize the temporal trend in topics, interpret the evolution within the last century and highlight any possible research gaps. Scopus® database was screened to select 18 records. Findings revealed an increasing trend in research records since 1994. TM identified terms with the highest weighted frequency and TA highlighted the main research areas, namely "Nutraceutical supports and their anti-inflammatory/antioxidant properties", "AHCC and nucleotides in CanL", "Vit. D3 and Leishmaniosis", "Functional food effects and Leishmaniosis" and "Extract effects and Leishmaniosis". Despite the existing academic interest, there are only a few studies on this issue so far, which reveals a gap in the literature that should be filled.

Evaluation of urinary podocin and nephrin as markers of podocyturia in dogs with leishmaniosis

BACKGROUND

Renal disease is the main cause of death in canine leishmaniosis. Detection of an active glomerular injury is important to identify early renal damage and to prevent the development of chronic kidney disease. Podocyturia can indicate renal injury, and podocyte-associated molecules such as podocin and nephrin can be used to identify podocyturia. The purpose of the study was to evaluate urinary podocin and nephrin concentrations in dogs with leishmaniosis as markers of podocyturia.

METHODS

A total of 35 healthy dogs and 37 dogs with leishmaniosis were enrolled in the study. Dogs with leishmaniosis were classified according to the staging of the International Renal Interest Society (IRIS). Urinary podocin and nephrin concentrations were measured in all dogs with a validated enzyme-linked immunosorbent assay test and normalized to creatinine (uPoC and uNeC, respectively). The demographic, clinical, and laboratory data from both groups were analyzed and compared. Subsequently, the laboratory results were analyzed and compared according to IRIS staging in dogs in IRIS stage I and dogs in IRIS stage II + III + IV. The Pearson's correlation test evaluated the relationship between urinary markers of podocyturia.

RESULTS

Compared with healthy dogs, lower urinary podocin [median values (IQR): 15.10 (11.75-17.87) ng/ml versus 8.63 (7.08-13.56) ng/ml; P < 0.01] and nephrin [median values (IQR): 3.2 (3.62-5.43) ng/ml versus 2.67 (2.06-3.44) ng/ml; P < 0.01] were found in infected sick dogs. No significant differences were observed in the uPoC and uNeC between the two groups. Urinary nephrin and podocin concentrations were higher in healthy dogs and in dogs in IRIS stage I (both P < 0.05) compared with dogs in IRIS stages II + III + IV. No significant differences were found for uPoC and uNeC between healthy dogs and dogs with leishmaniosis in different IRIS clinical stages.

CONCLUSIONS

Dogs with leishmaniosis had a low concentration of podocin and nephrin in more advanced IRIS clinical stages, when kidney disease was more severe compared with healthy dogs and dogs in IRIS stage I with mild disease. Urinary nephrin was detectable for the first time in healthy non-infected dogs.

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.

Treatment of Canine Leishmaniasis with Meglumine Antimoniate: A Clinical Study of Tolerability and Efficacy

Antimoniate therapy, in association with allopurinol, is one of the first-line treatments of canine leishmaniasis (CanL). This study evaluates the potential adverse effects associated with aNm in the treatment of CanL through both a retrospective analysis and a long-term prospective study also aimed to investigate its efficacy. The retrospective study reviewed records of 87 dogs with CanL with at least one follow-up available during or at the end of therapy with aNm (Glucantime®) at a dose of 50 mg/kg administered subcutaneously twice a day in association with allopurinol. In total, 29.8% of dogs showed adverse effects during treatment as local reactions at the injection site (n = 6), severe systemic reaction to pain (originating from the inoculation site) with depression and anorexia (n = 4), systemic disease due to renal function worsening (n = 4), acute pancreatitis (n = 1), diarrhea (n = 5), vomiting (n = 3) and severe idiosyncratic skin reactions (n = 3). Of these dogs, 13 (14.9%) required treatment suspension. The prospective study included 16 dogs, selected among the LeishVet stages II and III CKD IRIS stage 1 (International Renal Interest Society staging of canine Chronic Kidney Disease) and treated with the same aNm plus allopurinol protocol as in the retrospective study and observed for 360 days; 2 dogs were excluded for severe reactions at the injection site. Mild and transient adverse events were reported in the other 4 dogs. The criteria used to evaluate the efficacy of treatment with aNm were as follows: a reduction in the clinical score and improvement and/or normalization of laboratory parameters, negativization of PCR on the bone marrow samples and disease-free interval time. The proportion of reduction in the clinical score reached 91.9% at D180. No animals showed clinical laboratory relapse during the whole study duration and interestingly, the PCR results showed complete negativity between D0 and D60 in 78.5% of animals. Veterinarians must be vigilant regarding the potentially serious adverse effects associated with aNm and promptly stop drug administration if unexpected clinical manifestations occur. On the other hand, they should not discard its use for CanL treatment since it is confirmed that aNm in association with allopurinol is highly effective in controlling CanL.

Survival time and prognostic factors in canine leishmaniosis in a non-endemic country treated with a two-phase protocol including initial allopurinol monotherapy

BACKGROUND

Leishmania infantum is an intracellular protozoan parasite which is endemic in countries of the Mediterranean Basin. Leishmaniosis is increasingly diagnosed in non-endemic areas due to the relocation of dogs from endemic areas and the travel of dogs to and from these areas. The prognosis of leishmaniosis in these dogs may differ from that of those in endemic areas. The aims of this study were (1) to determine the Kaplan-Meier estimated survival time for dogs with leishmaniosis in the Netherlands (a non-endemic country), (2) to determine if clinicopathological variables at the time of diagnosis predicted the survival of these dogs, and (3) to evaluate the effect of a two-phase therapy protocol of allopurinol monotherapy followed by meglumine antimoniate and/or miltefosine in the case of incomplete remission or relapse.

METHODS

The database of the Department of Clinical Sciences of Companion Animals of the Faculty of Veterinary Medicine, Utrecht University was investigated for leishmaniosis patients. Patient records were reviewed for signalment and clinicopathological data at the time of diagnosis. Only treatment-naive patients were included. Follow-up was performed during the study by phone contact and included treatment received and date and cause of death. Univariate analysis was performed using the Cox proportional hazards regression model.

RESULTS

The estimated median Kaplan-Meier survival time was 6.4 years. In the univariate analysis, increases in monocyte, plasma urea and creatinine concentrations, and urine protein to creatinine ratio were all significantly associated with decreased survival time. The majority of patients only received allopurinol monotherapy.

CONCLUSIONS

Canine leishmaniosis patients in our study population in the Netherlands, which is non-endemic for the disease, had an estimated Kaplan-Meier median survival time of 6.4 years, which is comparable to the outcome of other reported therapy protocols. Increased plasma urea and creatinine concentrations and monocyte concentration were statistically associated with an increased risk of death. We conclude that initial allopurinol monotherapy for 3 months should be effective in more than half of canine leishmaniosis cases, provided there is adequate follow-up, and that meglumine antimoniate or miltefosine therapy should be started as the second phase of the protocol in cases where remission is incomplete or there is a relapse.

Advanced approaches for the diagnosis and chemoprevention of canine vector-borne pathogens and parasites-Implications for the Asia-Pacific region and beyond

Vector-borne pathogens (VBPs) of canines are a diverse range of infectious agents, including viruses, bacteria, protozoa and multicellular parasites, that are pernicious and potentially lethal to their hosts. Dogs across the globe are afflicted by canine VBPs, but the range of different ectoparasites and the VBPs that they transmit predominate in tropical regions. Countries within the Asia-Pacific have had limited prior research dedicated to exploring the epidemiology of canine VBPs, whilst the few studies that have been conducted show VBP prevalence to be high, with significant impacts on dog health. Moreover, such impacts are not restricted to dogs, as some canine VBPs are zoonotic. We reviewed the status of canine VBPs in the Asia-Pacific, with particular focus on nations in the tropics, whilst also investigating the history of VBP diagnosis and examining recent progress in the field, including advanced molecular methods, such as next-generation sequencing (NGS). These tools are rapidly changing the way parasites are detected and discovered, demonstrating a sensitivity equal to, or exceeding that of, conventional molecular diagnostics. We also provide a background to the armoury of chemopreventive products available for protecting dogs from VBP. Here, field-based research within high VBP pressure environments has underscored the importance of ectoparasiticide mode of action on their overall efficacy. The future of canine VBP diagnosis and prevention at a global level is also explored, highlighting how evolving portable sequencing technologies may permit diagnosis at point-of-care, whilst further research into chemopreventives will be essential if VBP transmission is to be effectively controlled.

Efficacy of domperidone plus renal diet in slowing the progression of chronic kidney disease in dogs with leishmaniosis

BACKGROUND

Chronic kidney disease (CKD) represents the main cause of mortality in dogs with leishmaniosis. Domperidone has recently been reported to improve kidney function in leishmaniotic dogs affected by CKD. Serum symmetric dimethylarginine (sSDMA) has also been shown to be a useful biomarker for earlier detection of decreased kidney function when compared to serum creatinine (sCr). This study aimed to assess the efficacy of domperidone plus renal diet in slowing the progression of nephropathy in leishmaniotic dogs with CKD, evaluating sSDMA and sCr as markers of kidney function.

METHODS

This study was a therapeutic, prospective, randomized, controlled, 11-month-long field trial. Dogs were recruited if classified as "exposed" to or "infected" with Leishmania infantum and affected by CKD at early stages. After enrolment (T0), dogs were randomized into groups T (treatment) and C (control). All dogs were fed a renal diet and then followed up at 90 (T1), 210 (T2), and 330 (T3) days after inclusion in the study. At T1 and T2, dogs in group T received an oral suspension of domperidone (1 ml/10 kg once a day for up to 28 days).

RESULTS

Twenty-two dogs (i.e., n = 12 in group T and n = 10 in group C) completed the study. At T0, the entire population of enrolled dogs presented a mean sSDMA value of 16.5 ± 3.4 μg/dl. At T1 (i.e., after 3 months of renal diet), sSDMA was significantly decreased in both groups, with an sSDMA of 13.1 ± 4.4 μg/dl for the entire population involved. From T1 to T3, sSDMA gradually increased in group C, while remaining stable in group T, which continued to show a significantly lower value of sSDMA at T3 than at T0. Regarding sCr, at T0 and T1, the mean values of the entire population of dogs were 1.1 ± 0.3 and 1.0 ± 0.4 mg/dl, respectively, with no statistical differences between groups T and C. In group T, sCr decreased significantly from T0 to T1, while returning at T3 to values similar to T0.

CONCLUSIONS

In this study, domperidone plus renal diet reduced the progression of kidney disease in leishmaniotic dogs affected by CKD.

Review of Novel Oral Amphotericin B Formulations for the Treatment of Parasitic Infections

Amphotericin B (AmpB) is a polyene macrolide antibiotic used in the treatment of blood-borne parasitic and fungal infections. However, its use, particularly in the developing world, has been limited by dose-dependent kidney toxicity, other systemic-related toxicity issues following injection, the inconvenience of parenteral administration, and accessibility. Oral formulation approaches have focused on the dual problem of solubility and permeability of AmpB, which is poorly water soluble, amphoteric and has extremely low oral bioavailability. Therefore, to enhance oral absorption, researchers have employed micellar formulations, polymeric nanoparticles, cochleates, pro-drugs, and self-emulsifying drug delivery systems (SEDDS). This paper will highlight current uses of AmpB against parasitic infections such as leishmaniasis, preclinical and clinical formulation strategies, applications in veterinary medicine and the importance of developing a cost-effective and safe oral AmpB formulation.

Canine Leishmaniasis: Update on Epidemiology, Diagnosis, Treatment, and Prevention

Dog are the main reservoir of Leishmania infantum, causing canine leishmaniasis, an incurable multisystemic disease that leads to death in symptomatic dogs, when not treated. This parasite causes visceral, cutaneous, and mucosal leishmaniasis in people in the Mediterranean Basin, North Africa, South America, and West Asia. This disease is mostly unknown by veterinarians outside the endemic areas, but the disease is expanding in the Northern Hemisphere due to travel and climate change. New methodologies to study the epidemiology of the disease have found new hosts of leishmaniasis and drawn a completely new picture of the parasite biological cycle. Canine leishmaniasis diagnosis has evolved over the years through the analysis of new samples using novel molecular techniques. Given the neglected nature of leishmaniasis, progress in drug discovery is slow, and the few drugs that reach clinical stages in humans are unlikely to be commercialised for dogs, but several approaches have been developed to support chemotherapy. New-generation vaccines developed during the last decade are now widely used, along with novel prevention strategies. The implications of the epidemiology, diagnosis, treatment, and prevention of canine leishmaniasis are fundamental to public health.

Review and statistical analysis of clinical management of feline leishmaniosis caused by Leishmania infantum

Background

There is limited information about feline leishmaniosis (FeL) management in clinical practice. Leishmania infantum is the species of Leishmania most frequently reported in both dogs and cats in countries of the Mediterranean region (henceforth ‘Mediterranean countries’), Central and South America, and Iran. This study was conducted to provide veterinary clinicians with an updated overview of evidence-based information on leishmaniosis in cats.

Methods

A review was performed using PubMed, Science Direct, Google Scholar and Web of Science. Case reports of FeL caused by L. infantum were sought for the period 1912 to 1 June 2021.

Results

Sixty-three case reports are included in this review. Fifty-nine out of the 63 cats were from Europe, mostly from Mediterranean countries (88.9%). Most of them were domestic short-haired cats (90%) with a mean age of 7.9 years, and had access to the outdoors (77.3%). Sixty-six percent of the cats had comorbidities, of which feline immunodeficiency virus infection was the most frequent (37.7%). Dermatological lesions (69.8%) was the most frequent clinical sign, and hyperproteinemia (46.3%) the most frequent clinicopathological abnormality. Serology was the most performed diagnostic method (76.2%) and was positive for 93.7% of cats. Medical treatment was applied in 71.4% of cats, and allopurinol was the most used drug (74.4%). Survival time was greater for treated cats (520 days; 71.4% of cats) than non-treated cats (210 days; 25.4%).

Conclusions

The majority of the cats had comorbidities, of which feline immunodeficiency virus was the most frequent. Dermatological lesions were frequently reported, and systemic clinical signs and clinicopathological abnormalities were also common. Serology may be useful for the diagnosis of FeL in clinical practice, and a positive titer of ≥ 1/40 may be a useful cut-off for sick cats. The reported treatments and dosages varied, but there was a good clinical response and longer survival in most of the cats treated with allopurinol monotherapy.

Graphical abstract

Dogs with leishmaniosis: how are we managing proteinuria in daily practice? A Portuguese questionnaire-based study

Background

Proteinuria is a common finding in dogs with leishmaniosis. Although antileishmanial therapeutic protocols are widely implemented, little information is available on which treatments are most adequate for identifying proteinuria in patients with canine leishmaniosis (CanL), especially regarding the use of immunosuppressants. The aim of this study was to explore the current paradigm regarding the antiproteinuric approach adopted by veterinary practitioners in Portugal to treat dogs with CanL.

Methods

A questionnaire-based study was developed using Google Forms®. The questionnaire presented a number of different hypothetical scenarios of CanL, and the topics surveyed included the general features of the respondents and the protocols preferred by these respondents to manage proteinuria in the presented scenarios, including choice of therapeutic drugs, appropriate diet and use of immunosuppressants, in dogs with immune-mediated glomerulonephritis. The questionnaire was internally prevalidated and diffused online over a 2-month period through Portuguese veterinary social networking groups, and data were collected for descriptive analysis.

Results

A total of 86 veterinary practitioners responded to the survey. When exposed to theoretical scenarios of proteinuria in dogs with CanL at stages IIb, III and IV (LeishVet guidelines), 16.3%, 62.8% and 93.8% of the respondents, respectively, answered that they would treat it. The dog was started on a renal diet as therapy by 28.6%, 83.3% and 97.4% of respondents, respectively. Angiotensin-converting enzyme inhibitors (ACEI) were prescribed by 100%, 85.2% and 78.9% of respondents as first-choice drugs for CanL at stages IIb, III and IV, respectively, with ACEI used in monotherapy by 64.3%, 40.7% and 46.1%. In comparison, protocols using ACEI in combination with other compounds were chosen by 7.1%, 33.3% and 39.5% of respondents, and combination therapy which did not include ACEI was the choice of 0.0%, 12.9% and 14.5%. Regarding immunosuppressants, 44.2% of the respondents answered they would prescribe them, with 97.4% electing for prednisolone and 5.3% choosing mycophenolate mofetil.

Conclusions

Among the veterinary practitioners who responded, proteinuria treatment was considered since stage IIb CanL, although implementation of a therapeutic approach was more evident in advanced CanL stages. ACEI were the first-choice drugs, particularly for the treatment of stage IIb CanL; in advanced stages, a combination of antiproteinuric drugs was more often used. Immunosuppressant use was controversial, although when applied, prednisolone was the preferred choice. These findings reinforce the small body of evidence that supports the use of such drugs and the need to further explore their role in CanL.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05222-w.

Leishmaniosis caused by Leishmania infantum in ferrets: Update review

Leishmaniosis in domestic ferrets (Mustela putorius furo) is a disease caused by Leishmania infantum, a parasite transmitted through the bite of an infected female phlebotomine sand fly. Among vertebrates, the dog is the primary domestic reservoir of the parasite; however, other domestic animals can be implicated such as cats. The first description of a clinical case of leishmaniosis in domestic ferrets was reported recently. As a result, new knowledge has been published including empirically based treatment protocols, confirmatory techniques to detect the presence of the parasite infection and seasonal variation in the antibodies against Leishmania in apparently healthy domestic ferrets. The most common clinical signs observed are enlargement of peripheral lymph nodes and skin lesions such as papular and/or ulcerative dermatitis. Additionally, the most frequent laboratory alterations seen are hyperproteinaemia with hyperglobulinaemia and biochemical analytes alterations depending on the affected tissue. Two different therapeutic protocols have been described to treat domestic ferrets with leishmaniosis: meglumine antimoniate plus allopurinol protocol or miltefosine plus allopurinol protocol. These treatment protocols seemed to be able to control the Leishmania infection, although the presence of xanthinuria could be detected. The susceptibility of domestic ferrets to Leishmania infantum, the clinical picture, treatment of infected animals and prevention are poorly understood, due to the scarcity of recent description in the literature. Different proposed diagnostic algorithms have been included for domestic ferrets with suspected leishmaniosis, clinically healthy domestic ferrets and animals as blood donors. In this sense, the present review provides updated data on scientific knowledge of leishmaniosis in ferrets.

Drug-Dosing Adjustment in Dogs and Cats with Chronic Kidney Disease

Chronic kidney disease is a common kidney disorder in adult and aged dogs and cats; the management of associated complications and comorbidities generally requires a life-long medical treatment to ensure a good quality of life of affected patients. However, indications and the literature on drug dosing in dogs and cats with chronic kidney disease are often lacking. The aim of this review is to revise the current literature on drug dosing in canine and feline patients with renal impairment, with a special focus on the most commonly used medications to manage chronic kidney disease and possible comorbidities.

Nutritional Modulation of the Immune Response Mediated by Nucleotides in Canine Leishmaniosis

Leishmaniasis is an emerging, uncontrolled, and neglected zoonotic disease. Climate change is contributing to its ongoing global expansion. The dog is the main reservoir; hence the importance of implementing effective treatment, prevention, and control measures in this animal species to protect public health. However, although the standard treatment for canine leishmaniosis (CanL) is effective, it does not provide full parasitological clearance, and side effects and drug resistance have been described. The host's immune system plays a key role in the establishment and evolution of leishmaniasis. Dietary nucleotides modulate the immune response and, given their reported efficacy and safety in sick and clinically healthy Leishmania-infected dogs and because they represent a sustainable option with no associated side effects or resistance, they could be included within the prevention, treatment, and control strategies for leishmaniasis. This article briefly summarizes the scientific literature on CanL management, including unresolved issues, and reviews the scientific evidence on immunomodulatory effects of dietary nucleotides in different animal species. It also proposes a CanL management algorithm, including nucleotides. It is concluded that nutritional modulation of the immune response with nucleotides can contribute to better management of leishmaniasis following a One Health approach, especially in the COVID-19 era.

Antileishmanial Drug Discovery and Development: Time to Reset the Model?

Leishmaniasis is a vector-borne parasitic disease caused by Leishmania species. The disease affects humans and animals, particularly dogs, provoking cutaneous, mucocutaneous, or visceral processes depending on the Leishmania sp. and the host immune response. No vaccine for humans is available, and the control relies mainly on chemotherapy. However, currently used drugs are old, some are toxic, and the safer presentations are largely unaffordable by the most severely affected human populations. Moreover, its efficacy has shortcomings, and it has been challenged by the growing reports of resistance and therapeutic failure. This manuscript presents an overview of the currently used drugs, the prevailing model to develop new antileishmanial drugs and its low efficiency, and the impact of deconstruction of the drug pipeline on the high failure rate of potential drugs. To improve the predictive value of preclinical research in the chemotherapy of leishmaniasis, several proposals are presented to circumvent critical hurdles-namely, lack of common goals of collaborative research, particularly in public-private partnership; fragmented efforts; use of inadequate surrogate models, especially for in vivo trials; shortcomings of target product profile (TPP) guides.

Effect of domperidone (leisguard®) on antibody titers, inflammatory markers and creatinine in dogs with leishmaniosis and chronic kidney disease

Background

Immunotherapeutic drugs, such as domperidone, have been shown to be promising treatments against canine leishmaniosis (CanL), but limited data are available. The aim of this pilot study (therapeutic, prospective and non-controlled) was to evaluate the effect of domperidone on serum antibody titers of Leishmania infantum, globulins, gamma globulins, acute-phase proteins (e.g. C-reactive protein [CRP]), big endothelin-1 (big ET-1), serum creatinine (SC) and proteinuria in dogs with leishmaniosis affected by chronic kidney disease (CKD).

Methods

Dogs were recruited if “exposed” to or “infected” with L. infantum and affected by CKD (IRIS stage 1 [proteinuric] or IRIS stage 2–3a [SC < 3.5 mg/dl; proteinuric or non-proteinuric]). After inclusion, an oral suspension of domperidone was administered, and the dogs were followed up for 180 days, with checks at 30, 60, 90 and 180 days after initial treatment.

Results

Of the 14 recruited dogs, nine showed a statistically significant reduction in SC (χ² = 9.1, df = 3, P = 0.028), but not in the urine protein/creatinine ratio (χ² = 6.43, df = 3, P = 0.092). All dogs showed a significant reduction in antibody titers for L. infantum (χ² = 9.56, df = 2, P = 0.008), globulins (χ² = 11.08, df = 3, P = 0.011) and gamma globulins (χ² = 12.38, df = 3, P = 0.006) during the study period. There was also a statistically significant reduction in CRP (χ² = 16.7, df = 3, P = 0.001), but not in big ET-1 (χ² = 2.04, df = 3, P = 0.563).

Conclusions

This study provides preliminary results on the ability of domperidone to improve SC and reduce anti-L. infantum antibody titers, globulins, gamma globulins and CRP in dogs with leishmaniosis and CKD.

Graphical abstract

Detection of Leishmania tarentolae in lizards, sand flies and dogs in southern Italy, where Leishmania infantum is endemic: hindrances and opportunities

Background

Leishmania tarentolae is a protozoan isolated from geckoes (Tarentola annularis, Tarentola mauritanica), which is considered non-pathogenic and is transmitted by herpetophilic Sergentomyia spp. sand flies. This species occurs in sympatry with Leishmania infantum in areas where canine leishmaniasis is endemic. In the present study, we investigated the circulation of L. tarentolae and L. infantum in sand flies, dogs and lizards in a dog shelter in southern Italy, where canine leishmaniasis by L. infantum is endemic.

Methods

Sheltered dogs (n = 100) negative for Leishmania spp. (March 2020) were screened by immunofluorescence antibody test (IFAT) using promastigotes of both species at two time points (June 2020 and March 2021). Whole blood from dogs, tissues of Podarcis siculus lizards (n = 28) and sand flies (n = 2306) were also sampled and tested by a duplex real-time PCR (dqPCR). Host blood meal was assessed in sand flies by PCR.

Results

Overall, 16 dogs became positive for L. infantum and/or L. tarentolae by IFAT at one or both sampling periods. One canine blood sample was positive for L. infantum, whilst two for L. tarentolae by dqPCR. At the cytology of lizard blood, Leishmania spp. amastigote-like forms were detected in erythrocytes. Twenty-two tissue samples, mostly lung (21.4%), scored molecularly positive for L. tarentolae, corresponding to 10 lizards (i.e., 35.7%). Of the female Sergentomyia minuta sampled (n = 1252), 158 scored positive for L. tarentolae, four for L. infantum, and one co-infected. Two Phlebotomus perniciosus (out of 29 females) were positive for L. tarentolae. Engorged S. minuta (n = 10) fed on humans, and one P. perniciosus, positive for L. tarentolae, on lagomorphs.

Conclusions

Dogs and lacertid lizards (Podarcis siculus) were herein found for the first time infected by L. tarentolae. The detection of both L. tarentolae and L. infantum in S. minuta and P. perniciosus suggests their sympatric circulation, with a potential overlap in vertebrate hosts. The interactions between L. tarentolae and L. infantum should be further investigated in both vectors and vertebrate hosts to understand the potential implications for the diagnosis and control of canine leishmaniasis in endemic areas.

Graphical abstract

A survey on canine leishmaniosis: Best practice and guideline awareness among Italian veterinary practitioners

Canine leishmaniosis (CanL) is a severe, potentially life-threatening disease of dogs and is considered one of the most important vector-borne zoonoses in Europe, where there is evidence that it is currently spreading into previously unaffected areas. Veterinary practitioners represent the first-line defence against CanL and in recent years, several guidelines have been developed to assist veterinarians in the correct diagnosis, management and prevention of the disease. The present study was aimed at surveying Italian practitioners on how they manage CanL and compare results to recommendations from guidelines developed by the European Scientific Council for Companion Animal Parasites (ESCCAP®), by the Leishvet® organization and by the Canine Leishmaniasis Working Group (C.L.W.G.). Approximately 14.0 % of veterinarians contacted replied to the survey. Results suggest that Italian practitioners are aware of currently available guidelines for the management of CanL and adherence to recommendations is good. Interestingly, 16.0 % carry out year-long prevention, even though recent data suggest that transmission in Italy continues to be seasonal. In conclusion, the high awareness among practitioners reported here should be considered an excellent opportunity for guideline developers to continue updating their recommendations to include any new information that can support the correct management of CL.

Frequency of detection and load of amastigotes in the pancreas of Leishmania infantum-seropositive dogs: clinical signs and histological changes

BACKGROUND

Zoonotic visceral leishmaniasis is caused by the protozoan Leishmania infantum and is highly lethal in humans and dogs if left untreated. The frequency of this parasite and associated histological changes in the pancreas of dogs are poorly studied. Therefore, the objectives of this study were to evaluate the frequency of detection and load of amastigotes in the pancreas of L. infantum-seropositive dogs and to identify the clinical signs and histological changes associated with parasitism of this organ.

METHODS

One hundred forty-three dogs from an endemic area in Brazil that tested seropositive for L. infantum were studied. The dogs were clinically examined, killed, and necropsied between 2013 and 2014. One fragment of the pancreas was randomly collected for histopathology and immunohistochemistry, and spleen and bone marrow were collected for culture.

RESULTS

Leishmania amastigotes were detected in the pancreas of 22 dogs (15.4%) by immunohistochemistry, all exhibiting L. infantum parasitism in the spleen and/or bone marrow. Poor body condition and cachexia were only associated with infection of the pancreas with Leishmania spp. (p = 0.021) and were found in 40.9% of dogs with pancreatic infection. Anorexia, vomiting, and/or diarrhea were observed in 9.2% of dogs with pancreatitis. The median parasite load in the pancreas was 1.4 infected macrophages/mm². Pancreatic histological changes and their frequencies were: granulomatous pancreatitis (28.0%), lymphoplasmacytic pancreatitis (23.8%), acinar cell degeneration (6.3%), fibrosis (5.6%), hemorrhage (2.1%), eosinophilic pancreatitis (0.7%), suppurative pancreatitis (0.7%), and necrosis (0.7%).

CONCLUSIONS

The present results demonstrate that L. infantum is one of the etiological agents of chronic pancreatitis in dogs; however, the frequency of detection and parasite load are low in this organ. The lack of an association of poor body condition and cachexia with pancreatitis and the low frequency of clinical signs commonly associated with pancreatitis suggest that a significant portion of the organ is not affected by this parasite. On the other hand, the association of poor body condition and cachexia with concomitant infection of the pancreas, spleen, and/or bone marrow with this parasite suggests that these manifestations are the result of a more advanced stage of canine visceral leishmaniasis.

Diagnosis and clinical management of canine leishmaniosis by general veterinary practitioners: a questionnaire-based survey in Portugal

BACKGROUND

Canine leishmaniosis (CanL) can be appropriately managed following international recommendations. However, few studies have assessed the preferred protocols in real-life veterinary practice and whether these are in line with the guidelines. This survey aimed to investigate the current trends in the clinical management of CanL among veterinary practitioners in Portugal, taking into consideration different scenarios of infection/disease and the awareness of and application by veterinary practitioners of the current guidelines.

METHODS

A questionnaire-based survey was conducted online using an electronic platform. The following topics were surveyed: (i) general characteristics of the responding veterinarian; (ii) the preferred protocols used for the diagnosis, treatment and prevention of CanL, considering different theoretical scenarios of infection/disease; and (iii) the responding veterinarian's current knowledge and application of the existing guidelines on CanL. After internal validation, the survey was distributed online, for 2 months, via Portuguese social network veterinary groups. Data were collected for descriptive analysis.

RESULTS

Eighty-six replies were obtained. Analysis of the results showed that the preferred diagnostic techniques varied widely according to the theoretical scenario of infection/disease. In general daily practice, serology testing (enzyme-linked immunosorbent assay [ELISA]) was the most used tool (67.4%). The preferred matrices used for PCR test were lymph nodes (62.3%) and/or bone marrow (59.0%). Regarding treatment, for subclinical infection/stage I CanL, 51.2% of the respondents did not prescribe any medical treatment, but 98.8% proceeded with both monitoring and preventive measures. Among those who prescribed a treatment (n = 42), most chose domperidone (47.6%). For the treament of stages IIa, IIb and III CanL, allopurinol/meglumine antimoniate (MA) was chosen by 69.8, 73.3 and 51.2% of respondents, respectively, followed by allopurinol/miltefosine (20.9, 19.8 and 38.4%, respectively). In contrast, dogs with stage IV CanL were mostly treated with allopurinol/miltefosine (48.8%) rather than with allopurinol/MA (23.3%). The use of repellents was the preferred preventive strategy (98.8%). About 93.0% of responders were aware of the existence of guidelines, and most of these veterinarians consulted the guidelines of the LeishVet group and the Canine Leishmaniosis Working Group; however, 31.3% reported that they did not follow any specific recommendations.

CONCLUSIONS

Of the veterinarians responding to the survey, most reported following international guidelines for the clinical management of CanL. While allopurinol/MA was the preferred therapeutic protocol for the treatment of stages II/III CanL, allopurinol/miltefosine was the first choice for the treatment of stage IV CanL, possibly due to the unpredictable effect of MA on renal function. This study contributes to a better understanding of the trends in practical approaches to the treatment of CanL in Portugal.

Leishmania mexicana in a central Texas cat: clinical presentation, molecular identification, sandfly vector collection and novel management

Case summary

This case report documents the clinical appearance, diagnosis and novel treatment of a central Texas cat with cutaneous leishmaniosis. The cat presented with a linear erosion on the right pinnal margin, an ulcerated exophytic nodule on the right hock and a swelling in the right nostril. Cytological and histopathological findings were consistent with leishmaniosis. PCR confirmed the presence of Leishmania mexicana, a species endemic to Texas. An epidemiological investigation was conducted by trapping sandflies from the cat’s environment. Sandflies collected were identified as Lutzomyia species, known vectors of Leishmania species. Given the lack of validated medical therapies for L mexicana in cats, treatments typically prescribed for canine leishmaniosis were administered. Allopurinol achieved clinical success but was discontinued due to suspected drug-related neutropenia. Topical imiquimod also improved lesional skin but was not sustainable due to application difficulty. Oral administration of artemisinin resulted in significant clinical improvement of cutaneous lesions without reported adverse events. Nearly 8 months after the initiation of artemisinin therapy, the cat remained systemically healthy with stable lesions.

Relevance and novel information

This case report demonstrates endemic feline leishmaniosis in central Texas and provides the clinician with alternative therapeutic options for medical management.

Seasonal variation in canine anti-Leishmania infantum antibody titres

Quantitative anti-Leishmania antibody titres are critical in the management of dogs with leishmaniosis, from diagnosis to treatment and follow-up, and there is a paucity of data relating changes in antibody titres to sand fly vector seasonality. This study aimed to evaluate seasonal variations in anti-Leishmania infantum antibody titres in dogs from a hyperendemic area for canine leishmaniosis (CanL). Leishmania infantum-seropositive and clinically healthy dogs (n=65) were sampled in June 2019 (sand fly season) and again in February-March 2020 (non-transmission season) to monitor clinical status and serological titres. There was a reduction in anti-L. infantum antibody titres during the non-transmission season in most dogs (n=36; 55.4%), and 44% of those dogs (n=16/36) became seronegative (i.e. below the cut-off value of 1:80). Given the relevance of serology to epidemiological, preventive and clinical studies related to CanL, seasonal variations in antibody titres are important in areas where phlebotomine vectors have seasonal patterns of activity. Sand fly seasonal period must be considered in the interpretation of annual anti-L. infantum antibody screening test results in asymptomatic dogs, to make clinical decisions about staging, treatment and prevention.

Use of GnRH Agonist in Dogs Affected with Leishmaniosis

Sex-associated hormones such as testosterone have been demonstrated to modulate immune responses, which can result in different disease outcomes. The present study was aimed at evaluating the efficacy of a gonadotropin-releasing hormone GnRH agonist implant as deslorelin acetate in association with meglumine antimoniate plus allopurinol in dogs with canine leishmaniosis (CanL). Twenty-two dogs with CanL confirmed by clinical findings and laboratory tests were included in the study. Dogs were randomized into two groups. A control group (CTR, n = 12) was treated with meglumine antimoniate 50 mg/kg SC q 12 h for 28 days plus allopurinol at 10 mg/kg PO q 12 h for the whole study period (six months). An experimental group was treated with allopurinol and meglumine antimoniate, plus an implant of 4.7 mg deslorelin acetate (DES, n = 10). The animals were observed for three months, during which clinical evaluation, indirect fluorescent antibody test (IFAT) titre and testosterone assay were performed on time at day (D)0, 90 and 180. A significantly lower clinical score was recorded in DES than in CTR (p < 0.01) at D90 and D180 (p < 0.01). After 180 days of treatment (D180), a significant reduction of mean levels of IFAT was observed in the DES group (p = 0.03). A highly significant reduction of testosterone (p = 0.01) was observed in the DES group during the study. No statistical correlation between clinical scores, IFAT titres and testosterone within two groups was observed. Data suggested that the agonist of GnRH may be useful in the treatment of CanL.

Scientometric analysis of chemotherapy of canine leishmaniasis (2000-2020)

Background

Zoonotic visceral leishmaniasis by Leishmania infantum is a first-order pathology in canine veterinary clinics in endemic areas. Moreover, canine infections are considered the main reservoir for human disease; despite their importance in the control of the disease within a One Health approach, no scientometric study has been published. Aims of the study included analyzing the impact of canine leishmaniasis (CanL) on the scientific literature, drugs or combinations used, trends in the period from 2000 to 2020 and efficacy criteria employed.

Methods

A Web of Science (WOS)-based analysis of publications on CanL and chemotherapy of the disease in the period 2000–2020 was carried out using a stepwise methodology. Data were analyzed by year, geographical origin, chemical groups, drugs and combinations, and efficacy criteria.

Results

Reports on CanL (n = 3324) represented < 16% of all publications on leishmaniasis (n = 20,968), and of these around 18% (n = 596) were related to chemotherapy. Publication records on CanL followed the distribution of the infection by L. infantum in endemic areas although Mediterranean countries were overrepresented in the reports on chemotherapy of CanL. Publications on the main antileishmanial drugs used in clinical practice showed a sustained tendency in the period analyzed. Pentavalent antimonials (Sb^V), alone or in combination with allopurinol, represented > 50% of all publications on chemotherapy of CanL despite the availability of more recently marketed drugs.

Conclusions

Chemotherapy of CanL still relies on Sb^V and combinations and to a lesser extent on miltefosine (MIL). Reports on chemotherapy are scarce and mostly publicly funded, and the variability of experimental conditions hampers the direct comparison of the efficacy of drugs, combinations and schedules. The vast majority of reports on efficacy do not include any information on supportive therapy; this reduces the actual value of the studies if intended for the practical management of the disease. Complete reports on the chemotherapy (etiological + symptomatic) would add value to the trials performed.

Comparison of Two Dosing Regimens of Miltefosine, Both in Combination With Allopurinol, on Clinical and Parasitological Findings of Dogs With Leishmaniosis: A Pilot Study

Miltefosine (MIL)–allopurinol combination therapy administered at standard dosage is effective to treat canine leishmaniosis, nevertheless for some dogs the digestive tolerance of MIL is not acceptable. This study evaluates an alternative therapeutic protocol by using a modified dosage of MIL to increase its effectiveness and improve the digestive tolerance. Thirty-four Leishmania infantum owned naturally infected dogs were included and monitored for 180 days. The dogs were allocated in two randomized groups: Group X−18 dogs treated with MIL registered dose of 2 mg/kg, oral administration, once daily, for 28 days; Group Y−16 dogs treated with 1.2 mg/kg for 5 days followed by 2.5 mg/kg for 25 days. Both groups were also treated with allopurinol. Digestive tolerance was monitored by adverse events observation. Treatments effectiveness was evaluated by monitoring the reduction of clinical score, the improvement of clinicopathological abnormalities, the reduction of parasitological load by PCR and the number of relapses. 16.6% dogs of group X and 12.5% dogs of group Y showed treatment associated adverse events. The reduction of clinical score was 61.7% for group X and 71.6% for group Y. All dogs showed an improvement of laboratory parameters after treatment. Quantitative PCR showed better results in group Y compared to group X; relapses were only registered in four dogs of group X. The modified protocol demonstrates a better trend of results in term of tolerance, clinical effectiveness, parasitological load reduction and relapses control, suggesting it could be considered for new large-scale studies.

Influence of domperidone supplementation on short-term changes in C-reactive protein and paraoxonase-1 in dogs with leishmaniasis undergoing meglumine antimoniate and allopurinol therapy

BACKGROUND

C-reactive protein (CRP) and paraoxonase 1 (PON1) might increase and decrease in canine leishmaniasis (CanL), , and both can rapidly normalize after therapy. Recently, supplementation of domperidone with conventional therapy , increasing the activity of cells involved in acute phase responses in vitro. This combined therapy has been recommended to treat mild forms of CanL; however, no studies have investigated the effects of domperidone supplementation on early CRP or PON1 changes in dogs with CanL.

OBJECTIVES

The aim of this study was to evaluate whether domperidone, added to conventional treatments, modifies CRP concentration and PON1 activity kinetics in CanL dogs responsive to conventional therapy.

METHODS

Serum CRP concentrations and PON1 activities were measured in dogs with mild CanL before (t-0) and 3 (t-1), 7 (t-2), 14 (t-3), and 21 (t-4) days after treatment with N-methylglucamine antimoniate and allopurinol alone (n = 18) or combined with domperidone (n = 18).

RESULTS

C-reactive protein concentrations increased at t-1 in the domperidone group, especially when the CRP concentration at t-0 was normal. However, the concentrations normalized at t-4 in 18/18 dogs compared with 14/18 dogs not receiving domperidone. The median PON1 activity decreased at t-1 in the domperidone group, and this decrease was more significant in dogs with normal PON1 activity at t-0.

CONCLUSIONS

Based on these results, transient increases in CRP concentrations or decreases in PON1 activities after domperidone administration should not be erroneously interpreted as signs of a worsening disease process.

Mathematical Modelling Using Predictive Biomarkers for the Outcome of Canine Leishmaniasis upon Chemotherapy

Prediction parameters of possible outcomes of canine leishmaniasis (CanL) therapy might help with therapeutic decisions and animal health care. Here, we aimed to develop a diagnostic method with predictive value by analyzing two groups of dogs with CanL, those that exhibited a decrease in parasite load upon antiparasitic treatment (group: responders) and those that maintained high parasite load despite the treatment (group: non-responders). The parameters analyzed were parasitic load determined by q-PCR, hemogram, serum biochemistry and immune system-related gene expression signature. A mathematical model was applied to the analysis of these parameters to predict how efficient their response to therapy would be. Responder dogs restored hematological and biochemical parameters to the reference values and exhibited a Th1 cell activation profile with a linear tendency to reach mild clinical alteration stages. Differently, non-responders developed a mixed Th1/Th2 response and exhibited markers of liver and kidney injury. Erythrocyte counts and serum phosphorus were identified as predictive markers of therapeutic response at an early period of assessment of CanL. The results presented in this study are highly encouraging and may represent a new paradigm for future assistance to clinicians to interfere precociously in the therapeutic approach, with a more precise definition in the patient's prognosis.

Serum indirect immunofluorescence assay and real-time PCR results in dogs affected by Leishmania infantum: evaluation before and after treatment at different clinical stages

We compared results of a serum immunofluorescence assay (IFA) and lymph node quantitative PCR (qPCR) in dogs classified as exposed, infected, or sick because of leishmaniasis. We also determined how IFA or qPCR results changed in response to treatment and reflected different clinical and clinicopathologic improvement of dogs. We included 108 dogs in our retrospective study: 12 exposed, 25 infected, and 71 sick, as classified according to Canine Leishmaniasis Working Group standards. Between-group comparison showed higher IFA values ( p < 0.01) for sick dogs; qPCR values were higher for sick than infected dogs ( p < 0.01). A novel clinical and clinicopathologic score was created and applied to 50 sick dogs. Using this score, 41 were reclassified as partially recovered (PR) within 3 mo, and 37 as totally recovered (TR) 3-6 mo after presentation. Statistically significant differences in IFA values were found between the sick and TR dogs ( p < 0.01), but not between sick and PR dogs ( p = 0.98). During follow-up, qPCR revealed a progressive decrease in parasite load, with a statistically significant difference in sick versus PR ( p < 0.01), sick versus TR ( p < 0.01), and PR versus TR ( p < 0.01) dogs. A decrease of 1 point in the clinical score corresponded to 1.3 Leishmania/μL qPCR decrease ( p < 0.01) and decrease of 1:42 in IFA ( p < 0.01). Our findings confirm that the clinical status of dogs affected by leishmaniasis is closely related to parasite load and antibody level, both before and after treatment.

Canine visceral leishmaniosis: the relationship of blood serum thyroid hormones, lipids, and lipoproteins with clinical status

The objective of the present study was to investigate the role of thyroid hormones and lipid profile in development and outcome of canine visceral leishmaniosis (CVL). We therefore studied the relationships between blood serum thyroid hormones [total T4, free T4, total T3, and free T3], lipids, and lipoproteins [total cholesterol, triglyceride, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C)] and clinical status in dogs naturally infected with Leishmania infantum. Two groups of Leishmania-infected dogs [with no clinical signs (NCS; n = 15), and with clinical signs (CS; n = 16)] were assessed and compared with a group of healthy control dogs (n = 15). A significant decrease in serum total T4 (p < 0.05) concentration in the CS group was observed when compared to the NCS and control groups. The dogs in CS group revealed a significant decrease (p < 0.05) in free T4 concentration in comparison to the control group. The CS group presented a significant decrease in HDL-C (p < 0.01) concentrations, when compared to NCS and control groups. The observed findings in the present study suggested that thyroid hormone and lipoprotein alterations may have a role in susceptibility of dogs with Leishmania infection.

Antileishmanial Activity of Amphotericin B-loaded-PLGA Nanoparticles: An Overview

In recent decades, nanotechnology has made phenomenal strides in the pharmaceutical field, favouring the improvement of the biopharmaceutical properties of many active compounds. Many liposome-based formulations containing antitumor, antioxidant and antifungal compounds are presently on the market and are used daily (for example Doxil^®/Caelyx^® and Ambisome^®). Polymeric nanoparticles have also been used to entrap many active compounds with the aim of improving their pharmacological activity, bioavailability and plasmatic half-life while decreasing their side effects. The modulation of the structural/morphological properties of nanoparticles allows us to influence various technological parameters, such as the loading capacity and/or the release profile of the encapsulated drug(s). Amongst the biocompatible polymers, poly(D,L-lactide) (PLA), poly(D,L-glycolide) (PLG) and their co-polymers poly(lactide-co-glycolide) (PLGA) are the most frequently employed due to their approval by the FDA for human use. The aim of this review is to provide a description of the foremost recent investigations based on the encapsulation of amphotericin B in PLGA nanoparticles, in order to furnish an overview of the technological properties of novel colloidal formulations useful in the treatment of Leishmaniasis. The pharmacological efficacy of the drug after nanoencapsulation will be compared to the commercial formulations of the drug (i.e., Fungizone^®, Ambisome^®, Amphocil^® and Abelcet^®).

Use of acute phase proteins for the clinical assessment and management of canine leishmaniosis: general recommendations

BACKGROUND

Dogs with canine leishmaniosis (CanL) due to Leishmania infantum can show a wide spectrum of clinical and clinicopathological findings at the time of diagnosis. The aim of this paper is to describe the possible application of acute phase proteins (APPs) for the characterization and management of this disease, based on previously published information on the utility of APPs in CanL and the experience of the authors in using APPs as analytes in the profiling of canine diseases.

MAIN BODY

Dogs diagnosed with L. infantum infection by serology, polymerase chain reaction, cytological or histopathological identification, can be divided into three groups based on their clinical condition at physical examination and their APPs concentrations: Group 1: dogs with no clinical signs on physical examination and APPs in reference range; Group 2: dogs with changes in APPs but no clinical signs on physical examination; Group 3: dogs with clinical signs and changes in APPs. This report describes the main characteristics of each group as well as its association with the clinical classification schemes of CanL.

CONCLUSION

APPs concentration can be a useful clinical tool to characterize and manage CanL.

Use of urinary γ-glutamyl transferase (GGT) to monitor the pattern of proteinuria in dogs with leishmaniasis treated with N-methylglucamine antimoniate

The aim of this study was to assess if the coupled analysis of the urinary protein to creatinine (UPC) ratio and of the GGT/UC ratio (the ratio between urinary γ-glutamyl transferase activity and urinary creatinine) may be used in treated leishmaniotic dogs to differentiate dogs with transient impairment of tubular function from dogs with persistent tubular damage. To this aim, 40 urine from 10 proteinuric and leishmaniotic dogs that at the first visit had high GGT/UC ratio, consistent with tubular damage, were collected and analyzed before treatments and 2, 4 and 6 weeks after treatment with N-methylglucamine antimoniate and allopurinol. Compared with pre-treatment values, at the end of the study period the UPC ratio decreased only in 5/10 dogs, which, however, were still proteinuric or borderline proteinuric. Conversely, the GGT/CU ratio decreased in 8/10 dogs and in 3 of them the values at the end of the study period were below the threshold consistent with tubular proteinuria. The GGT/UC values at 6 weeks was significantly lower than before treatment. However, transient increases were frequent for both the analytes. These results indicate that in most of the dogs that remain proteinuric after treatment, likely due to the persistent glomerular damage, the GGT/UC ratio tends to normalize. This suggests that in these dogs tubular proteinuria at admission depends on functional impairment of tubular cells likely due to the overflow of proteins from damaged glomeruli. However, tubular proteinuria occasionally persists, suggesting that tubulointerstitial damages persist even in dogs responsive to treatments.

Prevention of disease progression in Leishmania infantum-infected dogs with dietary nucleotides and active hexose correlated compound

Background

The prevalence of Leishmania infantum infection in clinically healthy dogs can be several times higher than that of clinical disease in endemic areas. Although treatment is not recommended in dogs with subclinical infection, these animals should be managed to prevent disease progression and parasite transmission to human beings or to other dogs. Dietary nucleotides and active hexose correlated compound (AHCC) have been shown to modulate the immune response. A recent study in dogs with clinical leishmaniosis receiving an initial 28-day course of methylglucamine antimoniate showed that six-month administration of a dietary supplement containing nucleotides plus AHCC achieves similar efficacy to allopurinol. Since the type of immune response plays a key role in the evolution of patients with leishmaniosis, the present study was aimed at evaluating the preventive effect of this supplement in avoiding or delaying disease progression in clinically healthy Leishmania-infected dogs.

Methods

Forty-six dogs were included in this multicenter, randomized, double-blind, placebo-controlled trial. Dogs received once-daily oral administration of a placebo or a dietary supplement containing nucleotides plus AHCC. Disease progression was monitored throughout the study in both groups. At 0, 60, 180 and 365 days of treatment, clinical signs were evaluated using a validated clinical scoring system, and several analytes were measured from blood, urine, and bone marrow samples.

Results

During the study, a significantly lower (P = 0.047) proportion of dogs changed their clinical status and became sick in the supplement group (3/20; 15%), compared to the placebo group (10/22; 45.5%). ELISA-determined antibody titers were significantly reduced compared to baseline at all time points with the supplement (P < 0.01), but not with the placebo. The mean clinical score of disease severity was significantly lower in the supplement group after 180 days (P = 0.014). No significant differences were observed for the other parameters. The dietary supplement was well tolerated.

Conclusions

Oral administration of nucleotides plus AHCC for 365 days in clinically healthy L. infantum-infected dogs is safe, allows a significant reduction in anti-Leishmania antibodies, and leads to a lower disease progression rate, hence exerting a preventive effect.

Novel Areas for Prevention and Control of Canine Leishmaniosis

There have been multiple recent advances regarding tools for the control and prevention of canine leishmaniosis (CanL), including new preventative vaccines. In this review, these advances are evaluated based on control targets, including vector and parasite. Leishvet recommendations are provided for control practices based on the dog's risk of infection. New topical insecticide formulations have proven to be effective in preventing sand fly bites, and subsequently infection. Parasite control occurs through chemotherapeutic or immunologic means, which decrease or prevent transmission to other animals, including humans. Leishmaniosis control programs that include a combination of coordinated measures, either in individuals or for prevention across reservoir populations, are required.

Management, prevention and treatment of canine leishmaniosis in north-eastern Spain: an online questionnaire-based survey in the province of Girona with special emphasis on new preventive methods (CaniLeish vaccine and domperidone)

Knowledge of how canine leishmaniosis (CanL) is being managed clinically and its epidemiology is very important, since dogs are the main reservoir of human leishmaniosis. This study reports the results obtained through a questionnaire-based survey of veterinary practitioners in Girona province, a recognised, but non-documented endemic area in north-eastern Spain. The primary objective was to obtain data on the clinical management of CanL, focusing particularly on new preventive methods and therapeutic tools. The results show an extensive routine management of CanL cases and a widespread use of the CaniLeish (Virbac) vaccine and domperidone (Leisguard, Esteve). Adverse reactions were detected by a vast majority of the vaccine users (82 per cent), the most frequent being local reactions, apathy, fever and gastroenteritis. All the respondents had treated confirmed cases, and the therapeutic protocol most used was the combination of meglumine antimoniate (Glucantime, Merial) and allopurinol (Zyloric, GlaxoSmithKline).

Laboratory tests for diagnosing and monitoring canine leishmaniasis

Although several reviews on canine leishmaniasis have been published, none thoroughly described clinicopathologic abnormalities and their clinical usefulness. The aim of this review was to provide information concerning current diagnostic tests relevant for clinical pathologists and from a practical perspective. Specifically, in canine leishmaniasis, nonregenerative normocytic normochromic anemia, thrombocytopenia, or leukogram changes may be present. Clinical chemistry and urinalysis may indicate renal dysfunction (azotemia, decreased urine specific gravity, proteinuria) and an inflammatory/immune response (increased acute phase proteins [APP] or α₂ - and/or γ-globulins). Although a potential gammopathy is usually polyclonal, it may also appear oligo- or monoclonal, especially in dogs coinfected by other vector-borne pathogens. When lesions are accessible to fine-needle aspiration (lymphoadenomegaly, nodular lesions, joint swelling), cytology is strongly advised, as the presence of Leishmania amastigotes in a pattern of pyogranulomatous inflammation or lymphoplasmacytic hyperplasia is diagnostic. If the cytologic pattern is inconclusive, the parasite should be identified by histology/immunohistochemistry or PCR on surgical biopsies. Alternatively, cytology and PCR may be performed on bone marrow samples where amastigotes, along with erythroid hypoplasia, myeloid hyperplasia, plasmacytosis, or secondary dysmyelopoiesis can be observed. Dogs with overt leishmaniasis generally have high antibody titers, while low titers predominate in immunologically resistant infected dogs or in exposed dogs with no parasite confirmation. Quantitative serology is recommended in clinically suspect dogs as high-titer antibodies titers may confirm the clinical diagnosis. In confirmed and treated dogs, renal function and inflammatory/immune response variables should be periodically monitored.

Serum C-reactive protein and ferritin concentrations in dogs undergoing leishmaniosis treatment

Monitoring of selected serum acute phase proteins like C-reactive protein (CRP) and ferritin could be useful for evaluation of the response to treatment in both naturally-occurring and experimentally-induced leishmaniosis. However studies until date have only been focused on dogs with an adequate response to the treatment and there is a lack of knowledge about the possible associations between the CRP and ferritin and the different clinicopathological conditions that can appear after treatment. Thus, the main objective of this retrospective study was to evaluate and compare the serum concentration of CRP and ferritin between three possible situations that dogs which undergo leishmaniosis treatment could have: responsive with total recovery, responsive with only clinical recovery but persistent abnormalities in biochemical analytes, and unresponsive with clinical and biochemical changes. All dogs which totally recovered after treatment showed CRP and ferritin values within reference ranges. Most of dogs classified as having only partial clinical remission had CRP and ferritin within the reference range values despite the presence of other biochemical abnormalities such as hyperglobulinemia, hyperproteinemia, or proteinuria. On the other hand, most of dogs in the unresponsive group had increased CRP and ferritin. Although the study has limitations due to the variability in the protocols and time periods of treatments, it can be concluded that CRP and ferritin concentrations within the reference ranges are usually associated with the absence of clinical signs and adequate response to treatment and increased CRP and/or ferritin values could reflect a lack of appropriate response to treatment.