Advantages of real-time PCR assay for diagnosis and monitoring of canine leishmaniosis

Feline Leishmaniasis Caused by Leishmania infantum: Parasite Sequencing, Seropositivity, and Clinical Characterization in an Endemic Area From Brazil

Zoonotic leishmaniasis caused by Leishmania infantum is a disease of One Health concern since human and animal cases and environmental damage are interconnected. L. infantum has a complex epidemiological cycle with multiple hosts, including mammals-humans, domestic, and wild animals-and arthropod vectors. Knowledge on mammal infections in endemic areas is crucial for developing control strategies. This work aimed to detect and characterize L. infantum infection in domestic cats from areas where human and canine leishmaniasis cases occur. No cases of feline leishmaniasis (FeL) had been previously reported in those areas. Five municipalities from Bahia state were chosen, comprising 2,480.8 km² with 1,103,866 inhabitants. Ninety domiciliated and/or sheltered cats underwent clinical examination and serology by a rapid reference test recommended by the Brazilian government. Cytology, PCR, and parasite DNA sequencing were performed in bone marrow samples. Rapid tests detected antibodies in 5.6% (5/90) of the cats. Leishmania infantum infection was confirmed in 7.8% (7/90) of the cats by PCR, sequencing, and parasite isolation. Three out of the five municipalities (60%) had infected cats, and PCR positivity varied from 6.9 to 29%. One cat was categorized as harboring active L. infantum infection with amastigote forms in bone marrow smears. No clinical signs were detected at the first clinical exam, but 1 month later the cat developed severe FeL. The cat isolate was grown in culture, typed and its DNA sequence was homologous to the L. infantum reference strain (PP75). In conclusion, cats are potential hosts and may acquire L. infantum in endemic areas where canine and human cases occur. For cats, the need for surveillance, differential diagnosis and clinical care is highly recommended since a fast clinical progression of FeL developed in a subclinical animal. An accurate standardized immunodiagnostic assay for FeL is warranted.

First Description of Sarcoptic Mange in a Free-Ranging European Wildcat (Felis silvestris silvestris) from Spain

Simple Summary

Sarcoptic mange caused by the mite Sarcoptes scabiei is a worldwide-distributed skin infestation with a wide range of hosts, among them several species within the Felidae family. Sarcoptes scabiei was diagnosed in a dead adult female European wildcat (Felis silvestris silvestris) from Spain. This is the first description of Sarcoptes scabiei in a European wildcat. Since this is a species of conservation concern due to its critical demography in the southernmost population of the Iberian Peninsula, the impacts of infectious diseases, including sarcoptic mange, should be considered during disease surveillance programs of the species’ populations.

Abstract

Sarcoptic mange caused by the mite Sarcoptes scabiei is a worldwide-distributed skin infestation with a wide range of hosts, among them several species within the Felidae family. Sarcoptes scabiei was diagnosed in a dead adult female European wildcat (Felis silvestris silvestris) from Spain, based on histological evaluation of skin biopsies and identification of the arthropod from skin scrapings and molecular methods. This is the first description of Sarcoptes scabiei in a European wildcat. Due to its critical demography in the southernmost population of the Iberian Peninsula, the impacts of infectious diseases, including sarcoptic mange, as a new potential threat should be considered during disease surveillance programs of the species’ populations.

Vitamin d and leishmaniasis: Neither seasonal nor risk factor in canine host but potential adjuvant treatment through cbd103 expression

Vitamin D (VitD) deficiency has been shown to be a risk factor for a plethora of disorders. We have shown that dogs with clinical leishmaniasis presented lower VitD serum levels than non-infected dogs, and even lower than those with asymptomatic infection. However, if VitD deficiency is a risk factor to develop clinical leishmaniasis remains to be answered. It is also unknown if VitD participates in Leishmania control. First, we retrospectively analysed VitD concentration in serum samples from 36 healthy dogs collected in different periods of the year concluding that there isn't a seasonal variation of this vitamin in dogs. We also included 9 dogs with clinical leishmaniasis and 10 non-infected healthy dogs, in which we measured VitD levels at the beginning of the study, when all dogs were negative for serology and qPCR, and 1 year later. Whereas non-infected dogs showed no change in VitD levels along the study, those developing clinical leishmaniasis showed a significant VitD reduction at the end of the study (35%). When we compared VitD concentration between the two groups at the beginning of the study, no differences were detected (43.6 (38-59) ng/mL, P = 0.962). Furthermore, an in vitro model using a canine macrophage cell line proved that adding active VitD leads to a significant reduction in L. infantum load (31.4%). Analyzing expression of genes related to VitD pathway on primary canine monocytes, we showed that CBD103 expression was significantly enhanced after 1,25(OH)2D addition. Our results show that VitD concentration is neither seasonal nor a risk factor for developing canine leishmaniasis, but it diminishes with the onset of clinical disease suggesting a role in parasitic control. Our in vitro results corroborate this hypothesis and point out that VitD regulates infection through CBD103 expression. These results open the possibility for studies testing VitD as an adjuvant in leishmaniasis therapy.

An epidemiological study in wild carnivores from Spanish Mediterranean ecosystems reveals association between Leishmania infantum, Babesia spp. and Hepatozoon spp. infection and new hosts for Hepatozoon martis, Hepatozoon canis and Sarcocystis spp

The aetiology and epidemiology of vector borne apicomplexan Babesia and Hepatozoon and kinetoplastid Leishmania infantum infections in wildlife have not been explored in wide areas of southern Spain. We investigated these infections in 151 wild carnivores, including foxes, badgers, beech martens, hedgehogs, wild cats, Egyptian mongooses, otters, genets and racoons. Overall, Hepatozoon, Babesia and L. infantum infections were detected in 68%, 48% and 23% of the wild animals surveyed, respectively. L. infantum-infected wildlife were more likely to be also infected with the apicomplexan Hepatozoon and Babesia spp. compared to the non-infected counterparts (p < .05). We report for the first time Hepatozoon martis in badgers and wild cats and H. canis in beech martens, and a Babesia sp. in wild cats from Spain. Our results also indicate the widespread distribution of H. canis in foxes (91%) and beech martens (13%), H. martis in beech martens (81%), wild cats (20%) and badgers (13%), H. felis in wild cats (60%), B. vulpes in foxes (64%), Babesia sp. type A closely related to B. vulpes, in badgers (58%) and Babesia sp. in wild cats (20%). Moreover, L. infantum infection was found in foxes (29%), beech martens (13%), badgers (8%) and 1/3 Egyptian mongooses. We also detected Cytauxzoon sp. in a wild cat and the first Sarcocystis sp. in a genet. This study provided evidence of increased risk of L. infantum infection in wildlife animals co-infected with Babesia spp. or Hepatozoon spp. and indicated that these infections are widespread in wild carnivores from Spanish Mediterranean ecosystems.

Leishmania infantum in Tigers and Sand Flies from a Leishmaniasis-Endemic Area, Southern Italy

We detected Leishmania infantum infection in 45% of tigers and 5.3% of sand flies tested at a zoo in southern Italy in 2019. These infections in tigers and the abundance of Phlebotomus perniciosus sand flies represent a potential risk to other animals and humans living in or visiting the zoo.

Serum amyloid A levels and alpha 2 and gamma globulins on serum protein electrophoresis in cats exposed to and infected with Leishmania infantum

Background

Dogs are the main reservoir hosts of Leishmania infantum; nevertheless, recent investigations indicate a likely role for cats in the epidemiology of Leishmania infection. Feline leishmaniosis (FeL) remains poorly characterised, partly due to the lack of suitable diagnostic tools. This study aimed to compare serum amyloid A (SAA) levels and serum protein electrophoresis (SPE) profiles (specifically, alpha 2 and gamma globulins) in cats naturally exposed to or infected by L. infantum from southern Italy versus those of healthy controls and versus cats with neoplastic or inflammatory conditions from non-endemic areas.

Methods

Serum or plasma samples from four cohorts of cats were analysed for SAA levels and by SPE: (i) G1: healthy controls from Leishmania-non-endemic regions of Switzerland; (ii) G2: cats pre-diagnosed with neoplastic or inflammatory conditions available from the University of Cambridge sample archive; (iii) G3: L. infantum-seropositive, quantitative (q)PCR-negative cats from southern Italy; (iv) G4: L. infantum-seropositive and qPCR-positive cats from southern Italy. SAA data were assessed for normality and homoscedasticity using the Shapiro–Wilk and Levene’s tests, respectively; the Kruskall–Wallis test, followed by Dunn’s test with Bonferroni correction were subsequently used to compare SAA serum levels between groups. A weighted generalised linear model with a binomial distribution was used to assess statistically significant differences in the numbers of animals displaying elevated gamma globulins and increased alpha 2 globulins between groups.

Results

Overall, 68 samples were analysed (G1: n = 16, G2: n = 20, G3: n = 20, G4: n = 12). Cats suffering from neoplastic and inflammatory conditions (G2 ) showed significantly higher SAA levels than healthy controls (G1) (median values [interquartile range]: G1: 0.00 [0.00–0.00] mg/l versus G2: 0.85 [0.00–49.55] mg/l). G2, G3 and G4 cats showed higher percentages of individuals with increased alpha 2 globulins (percentages ± standard error: G1 = 20.0% ± 10.3, G2 = 80.0% ± 8.9, G3 = 70.0% ± 10.2, G4 = 75.0% ± 12.5) and gamma globulins (G1 = 0.0% ± 0, G2 = 65.0% ± 10.7, G3 = 50.0% ± 11.2, G4 = 58.3% ± 14.2) than healthy control cats (G1). For all three markers, no significant difference between cats within G2, G3 and G4 was recorded.

Conclusions

This study indicates that the proportions of animals with elevated levels of alpha 2 and gamma globulins are significantly higher in cats exposed to and infected with L. infantum. Levels of SAA and alpha 2 and gamma globulins may not be used to differentiate between L. infantum infection or exposure, and neoplastic and/or inflammatory conditions.

Graphic Abstract

In silico and in vitro evaluation of primers for molecular differentiation of Leishmania species

Leishmaniasis is a zoonotic disease caused by over 20 species of protozoan parasites of the genus Leishmania. Infection is commonly spread by sandflies and produces a wide spectrum of clinical signs and symptoms. Therefore, from an epidemiological and therapeutic standpoint, it is important to detect and differentiate Leishmania spp. The objective of this study was to combinate in silico and in vitro strategies to evaluate the analytical specificity of primers previously described in the literature. According to electronic PCR (e-PCR) analysis, 23 out of 141 pairs of primers selected through literature search matched their previously reported analytical specificity. In vitro evaluation of nine of these primer pairs by quantitative PCR (qPCR) confirmed the analytical specificity of five of them at the level of Leishmania spp., L. mexicana complex or Leishmania and Viannia subgenera. Based on these findings, the combination of e-PCR and qPCR is suggested to be a valuable approach to maximize the specificity of new primer pairs for the laboratory diagnosis of infections with Leishmania spp.

The efficacy of recombinant protein lbk39 for the diagnosis of leishmaniosis in dogs

Visceral leishmaniosis is one of the most important zoonotic diseases on the planet and dogs are the main reservoir of canine visceral leishmaniosis (CVL) in endemic areas. They play an important role in human infection because in dogs the disease appears long time after infection, and they can move uncontrollably, contributing to disperse the parasite. To take the decision to treat the animals or for euthanasia, in an elimination programme, in order to reduce the parasitic load, it is necessary to diagnose correctly, having more effective tools. Our group has developed a new recombinant antigen-based kinesin-related gene of Leishmania braziliensis (Lbk39), which shows 59% amino acid identity to the L. infantum homologue. The Lbk39 gene was synthesized, inserted into the pLEXSY-sat2 vector and transfected into L. tarentolae cells by electroporation. The recombinant protein was secreted in the culture with a C-terminal histidine marker, purified, generating a product at 337.68 μg mL-1. A total of 152 sera from dog's endemic and non-endemic areas were used, being 78 positives and 75 negatives. The antigen Lbk39 showed 100% sensitivity and 96.1% specificity. We compared this antigen with other antigens such as total extract of the parasite, TRDPP, and our data indicate that Lbk39 has potential application in the diagnosis of CVL through antibody detection.

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.

Molecular survey on tick-borne pathogens and Leishmania infantum in red foxes (Vulpes vulpes) from southern Italy

Red foxes (Vulpes vulpes) have been recognised to harbour and transmit a wide range of tick-borne pathogens (TBPs) including those of zoonotic concern. To investigate the prevalence and the distribution of TBPs and of Leishmania infantum in foxes (n = 244), spleen samples were collected within the frame of a multi-regional wildlife health surveillance program in Italy. A combined PCR/sequencing approach was performed for the detection of Anaplasma spp., Babesia spp., Borrelia spp., Ehrlichia spp., Hepatozoon spp. and L. infantum DNA. Overall, 146 foxes (59.8 %, 95 % CI: 53.6-65.8) tested positive for at least one pathogen with Hepatozoon canis being the most prevalent (i.e., n = 124; 50.8 %, 95 % CI: 44.6-57.0), followed by Babesia vulpes (n = 20; 8.2 %, 95 % CI: 5.4-12.3), different spirochete species from Borrelia burgdorferi sensu lato complex (n = 9; 3.7 %, 95 % CI: 1.9-6.9), Ehrlichia canis and L. infantum (n = 7; 2.9 % each, 95 % CI: 1.4-5.8), Anaplasma platys (n = 4; 1.6 %, 95 % CI: 0.6-4.1), Anaplasma phagocytophilum ecotype I and Candidatus Neoehrlichia sp. (n = 3; 1.2 % each, 95 % CI: 0.4-3.5). All samples scored negative for Babesia canis and Borrelia miyamotoi. This study revealed the presence of spirochetes from B. burgdorferi s.l. complex, Ca. Neoehrlichia sp., A. platys and A. phagocytophilum ecotype I in red fox population from Italy, underling the necessity to monitoring these carnivores, mainly because they live in contact with dogs and humans. Data on the tick fauna circulating on wildlife species will complement information herein obtained, instrumentally to establish preventive strategies for minimizing the risk of infection for animals and humans.

Vector-borne pathogens in dogs of different regions of Iran and Pakistan

Canine vector-borne diseases (CVBDs) are highly prevalent in tropical and subtropical countries, mainly due to favorable climate conditions and reduced adoption of preventive measures. This study aimed to provide a comprehensive overview on the prevalence of CVBDs in Iran and Pakistan where limited data are available. Blood samples were collected from 403 dogs from six provinces in Iran and Pakistan to assess the presence of pathogen DNA (i.e., Anaplasma spp., Coxiella burnetii, Ehrlichia spp., Rickettsia spp., Babesia spp., Hepatozoon spp., filarioids, and Leishmania spp.). Sera were also screened by an immunofluorescence antibody test for the detection of antibodies against Leishmania infantum. In total, 46.9% of dogs scored positive to Hepatozoon canis being the most frequently detected (41.4%), followed by Anaplasma platys (6.4%), Ehrlichia canis (3.4%), Rickettsia spp. (2.2%), Babesia vogeli (1.0%), and L. infantum (0.3%). A seroprevalence of 9.6% to anti-L. infantum IgG was also recorded. Data reported herein demonstrate that dogs from Iran and Pakistan are at a high risk of CVBDs, particularly of canine hepatozoonosis. Effective control strategies are advocated for minimizing the risk of infection in animals and humans, also in consideration of the zoonotic potential of some pathogens detected.

Asymptomatic Leishmania infection in blood donors from a major blood bank in Northeastern Brazil: a cross-sectional study

This study has estimated the risk of Leishmania transmission via blood transfusion in one of the largest blood banks in Northeastern Brazil, where visceral leishmaniasis is endemic. Five hundred blood samples from donors were tested for circulating Leishmania spp. DNA by real-time PCR. Positive samples were tested by a species-specific conventional PCR targeting Leishmania infantum . Overall, 6.2% (95% CI: 4.1–8.3%) of the samples carried Leishmania DNA and in one sample the species was confirmed as L. infantum . No statistically significant differences were found in relation to gender, sex, education level, incomeas well as the place of residence between positive and negative blood donors. Our results confirm the presence of asymptomatic Leishmania carriers among blood donors in a large blood bank in Northeastern Brazil. Considering the studied population, we estimate that for every 1,000 blood donors screened, 41 to 83 will be positive for Leishmania DNA. This finding reinforces the urgent need for elaborating specific Blood bank guidelines to allow the early detection of asymptomatic Leishmania carriers among blood donors before their blood products are transfused to uninfected individuals.

Detection of Leishmania infantum DNA in Pintomyia evansi and Lutzomyia longipalpis in Honduras

Background

The two most abundant sand fly species on the Honduran Pacific coast are Lutzomyia (Lutzomyia) longipalpis and Pintomyia (Pifanomyia) evansi. Both species are known vectors of Leishmania (Leishmania) infantum, the etiological agent of visceral leishmaniasis (VL) in the Americas. Although VL and non-ulcerative cutaneous leishmaniasis (NUCL) are endemic on the Pacific versant of the Central American Pacific, the latter is the most frequent manifestation of leishmaniasis there. We evaluated the circulation of Leishmania spp. in the sand fly species on El Tigre Island, an endemic area of NUCL.

Results

We collected 222 specimens of six sand fly species. Lu. longipalpis (180 specimens; 81%) and Pif. (Pi.) evansi (35 specimens; 16%) were the most abundant species. L. (L.) infantum DNA was detected in nine of the 96 specimens analyzed; seven of these specimens were identified as Lu. longipalpis, and the remaining two were Pi.evansi, with an infection rate of 9.4% and 2.7%, respectively.

Conclusion

We present the first record of L. (L.) infantum DNA in Pi.evansi from a NUCL endemic region of Central America. Our results suggest that Pi. evansi could be a secondary vector of L. (L.) infantum in the transmission cycle of leishmaniasis. The detection of natural infections of L. (L.) infantum in sand flies in this region contributes to an understanding of the epidemiology of leishmaniasis in Honduras.

Infection of dogs by Leishmania infantum elicits a general response of IgG subclasses

Leishmania infantum is the etiological agent of zoonotic visceral leishmaniasis. In endemic areas, canine infections are considered the main source of infection for human populations. Therefore, any control of human leishmaniasis must include the control of canine infections. Chemotherapy of leishmaniasis is inadequate and canine immunoprophylaxis has important limitations. Reports on the response of infected dogs are abundant but no clear picture of immune events has emerged. To shed some light on these shortcomings the specific IgG subclass response was followed in 20 Beagle dogs experimentally infected with L. infantum using monoclonal antibodies (MAb) specific for canine IgG₁, IgG₂, IgG₃ and IgG₄, along with ELISA and flow cytometry. Results showed that parasitic infection elicits a general response of all IgG subclasses, with a predominant IgG₁ response and without any evidence of IgG₁/IgG₂ dichotomy. These findings suggest that the inconsistent results reported previously could be related to the lack of specific reagents and not to the actual differences in the immune response of infected animals. Differential IgG subclass reactivity in ELISA and cytometry and the analysis of the reacting antigens could facilitate the diagnosis and prognosis of the disease and provide a useful tool for adequate therapeutics and vaccine development against leishmaniasis.

Comparison and clinical validation of qPCR assays targeting Leishmania 18S rDNA and HSP70 genes in patients with American Tegumentary Leishmaniasis

Leishmaniasis is a worldwide neglected disease, encompassing asymptomatic infections and different clinical forms, such as American Tegumentary Leishmaniasis (ATL) which is part of the complex of diseases caused by protozoan parasites from Leishmania genus, transmitted by sand fly vectors. As a neglected disease, much effort is still needed in treatment and diagnosis. Currently, ATL diagnosis is mainly made by parasite detection by microscopy. The sensitivity of the method varies, and factors such as collection procedures interfere. Molecular approaches, specially based on Real Time PCR (qPCR) technique, has been widely used to detect Leishmania infection and to quantify parasite load, once it is a simple, rapid and sensitive methodology, capable to detect low parasite concentrations and less prone to variability. Although many studies have been already published addressing the use of this technique, an improvement on these methodologies, including an analytical validation, standardization and data association is demanded. Moreover, a proper validation by the assay by the use of clinical samples is still required. In this sense, the purpose of the present work is to compare the performance of qPCR using two commonly used targets (18S rDNA and HSP70) with an internal control (RNAse P) in multiplex reactions. Additionally, we validated reactions by assaying 88 samples from patients presenting different clinical forms of leishmaniasis (cutaneous, mucosal, recent and old lesions), representing the diversity found in Brazil's Amazon Region. Following the methodology proposed herein, the results indicate the use of both qPCR assays, 18S rDNA and HSP70, to achieve a very good net sensitivity (98.5%) and specificity (100%), performing simultaneous or sequential testing, respectively. With this approach, our main goal is to conclude the first step of a further multicenter study to propose the standardization of detection and quantification of Leishmania.

Serological, molecular and clinicopathological findings associated with Leishmania infantum infection in cats in Northern Italy

OBJECTIVES

The aims of this study were to investigate the prevalence of Leishmania species infection in cats in Northern Italy and to evaluate the associations between infection and signalment and clinicopathological data.

METHODS

The study was carried out in a veterinary university hospital from June to November 2017. Blood, urine, conjunctival swabs and hair were collected from all randomly selected cats. Leishmania species infection was evaluated using the indirect fluorescent antibody test (IFAT), setting a cut-off value of 1:80, and using real-time PCR on blood, conjunctival and hair samples. A complete blood count, serum chemistry profile, serum electrophoresis and urinalysis were also carried out. The cats were grouped on the basis of the results of the diagnostic criteria adopted in positive, negative and unconfirmed Leishmania cases. Non-parametric variables and continuous data were compared among the study groups using the χ2 test and the Mann-Whitney U-test, respectively.

RESULTS

One hundred and fifty-two cats were included. Nineteen of the 152 (12.5%) cats were positive (18/152 [11.8%] showed an IFAT titre of ⩾1:80 and 1/152 [0.7%] was real-time PCR-positive from a hair sample); 106/152 (69.7%) cats were negative; and 27/152 (17.8%) cats were unconfirmed for Leishmania species. Total proteins, beta2-globulin and gamma-globulin were significantly increased in the positive Leishmania group compared with the negative group.

CONCLUSIONS AND RELEVANCE

The results of the present study demonstrated the spread of Leishmania infantum infection in cats in Northern Italy. Hyperproteinaemia and hypergammaglobulinaemia appeared to be significant clinicopathological abnormalities in this population of cats with L infantum infection.

Detection of Leishmania infantum DNA by real-time PCR in saliva of dogs

This study developed a real-time quantitative PCR (qPCR) assay to detect L. infantum kinetoplast DNA (kDNA) in canine saliva. The qPCR showed an efficiency of 93.8%, a coefficient of correlation of 0.996 and a detection limit of 0.5 fg/reaction (0.005 parasites), although it detected until 0.25 fg/reaction (0.0025 parasites). When samples from 12 dogs experimentally infected with L. infantum were collected, L. infantum kDNA was detected at 16-weeks post-infection (wpi) in 41.7% and 91.7% of saliva and bone marrow samples, respectively, and at 47-wpi in 75% of both samples. L. infantum kDNA can be detected by qPCR in canine saliva, with lower sensitivity in the early stages of infection and a lower parasite load estimation compared to bone marrow. However, saliva had similar sensitivities to bone marrow in the later stages of the infection and could be used to detect L. infantum kDNA being aware of its limitations.

Clinical leishmaniosis in a captive Eurasian otter (Lutra lutra) in Spain: a case report

Background

Captive and free-ranging wild mammals have been recognized as potential reservoirs of Leishmania infantum infection. The aim of this study was to describe the first clinical case of leishmaniosis in the Eurasian otter.

Case presentation

A case of clinical leishmaniosis is reported in a 4-year-old male Eurasian otter housed at a wildlife park (Murcia, South Eastern Spain). The Eurasian otter showed bilateral epistaxis, anorexia, apathy, and weight loss. A complete blood cell count and biochemical analyses revealed hyperproteinemia, hyperglobulinemia, decreases of paraoxonase-1, increases of haptoglobin and ferritin, and proteinuria. Bilateral nephropathy with hydronephrosis, mesenteric lymphadenomegaly, and ascites were also observed. L. infantum infection was confirmed by microscopy (amastigotes were detected in macrophages from spleen aspirate), molecular diagnosis (L. infantum DNA was detected by real-time polymerase chain reaction), and serology (anti-Leishmania IgG2 antibodies were detected by time-resolved immunofluorometry). The animal was treated with allopurinol for 3 months and gained weight, the epistaxis disappeared, and the ferritin concentration decreased.

Conclusions

This is the first report of clinical leishmaniosis in the Eurasian otter. Our results suggest that Eurasian otters are susceptible to infection with L. infantum and can develop clinical leishmaniosis in endemic areas.

Detection of Leishmania infantum DNA and antibodies against Anaplasma spp., Borrelia burgdorferi s.l. and Ehrlichia canis in a dog kennel in South-Central Romania

Canine vector-borne diseases are caused by pathogens transmitted by arthropods including ticks, mosquitoes and sand flies. Many canine vector-borne diseases are of zoonotic importance. This study aimed to assess the prevalence of vector-borne infections caused by Dirofilaria immitis, Ehrlichia canis, Borrelia burgdorferi sensu lato, Anaplasma spp. and Leishmania infantum in a dog kennel in Argeș County, Romania. Dog kennels are shelters for stray dogs with no officially registered owners that are gathered to be neutered and/or boarded for national/international adoptions by various public or private organizations. The international dog adoptions might represent a risk in the transmission of pathogens into new regions. In this context, a total number of 149 blood samples and 149 conjunctival swabs from asymptomatic kennel dogs were assessed using serology and quantitative real-time polymerase chain reaction. Antibodies against B. burgdorferi s.l. were detected in one dog (0.6%), anti-Anaplasma antibodies were found in five dogs (3.3%), while ten dogs (6.7%) tested positive for D. immitis antigen. Overall, 20.1% (30/149) of dogs were positive for L. infantum DNA. All samples were seronegative for anti-Leishmania antibodies. When adopting dogs from this region of Romania, owners should be aware of possible infection with especially L. infantum. The travel of infected dogs may introduce the infection to areas where leishmaniasis is not present.

Clinical and Immunological Features of Human Leishmania (L.) infantum-Infection, Novel Insights Honduras, Central America

Leishmania (Leishmania) infantum is the etiological agent of both American visceral leishmaniasis (AVL) and non-ulcerated cutaneous leishmaniasis (NUCL) in Honduras. Although AVL is the most severe clinical form of infection, recent studies have shown that human immune response to parasite infection can result in a clinical-immunological spectrum. The overall prevalence rate of infection and clinical-immunological profiles of the L. (L.) infantum infection in Amapala municipality, South Honduras was determined. We examined 576 individuals with diagnosis based on combined ELISA (IgG/IgM) and DTH assays. We also used genus-specific kDNA PCR and Hsp70 PCR-RFLP for NUCL cases. Clinical evaluation found 82% asymptomatic and 18% symptomatic individuals. All symptomatic cases (n = 104) showing NUCL were positive for parasites. We identified L. (L.) infantum species in 100% of the skin lesion scrapings and in 90% of the blood samples from NUCL cases studied. A total of 320 asymptomatic individuals were exposed (ELISA+ and/or DTH+), providing an overall L. (L.) infantum prevalence of 73.6%. Clinical, parasitological, and immunological evaluations suggest seven infection profiles, three asymptomatic and four symptomatic. This represents the first report on clinical and immunological features of human L. (L.) infantum-infection in Amapala municipality, Honduras.

Sirolimus enhances the protection achieved by a DNA vaccine against Leishmania infantum

Background

Leishmaniases are a group of neglected tropical parasitic diseases, mainly affecting vulnerable populations of countries with poor socioeconomic status. Development of efficient vaccines is a priority due to the increasing incidence of drug resistance and toxicity to current treatments. In the search for a safe and efficient protective vaccine for human and dog visceral leishmaniases, we analyzed the suitability of the immunomodulatory drug sirolimus (SIR) to boost a preventive DNA vaccine against leishmaniasis. SIR is an already marketed drug that has been described to boost immune protection against different disease models and has also emerged as a promising therapeutic drug against L. major.

Methods

Syrian hamsters were treated with SIR concomitantly with the administration of a DNA vaccine formulation consisting in four plasmids carrying the Leishmania genes LACK, TRYP, PAPLE22 and KMPII, respectively. Two weeks after the last vaccination, the animals were infected intraperitoneally with L. infantum parasites. Five weeks post-infection the parasite load was measured by real-time PCR in target tissues and immune response was evaluated by determining anti-Leishmania specific antibodies in combination with cytokine expression in the spleen.

Results

Our results show that the DNA vaccine itself efficiently reduced the burden of parasites in the skin (P = 0.0004) and lymph nodes (P = 0.0452). SIR administration also enhanced the protection by reducing the parasite load in the spleen (P = 0.0004). Vaccinated animals with or without SIR co-treatment showed lower IFN-γ expression levels than those found in the spleen of control animals. mRNA expression levels of NOS2 and IL-10 were found to be significantly higher in the vaccinated plus SIR treated group.

Conclusions

Co-administration of SIR enhances a DNA vaccination regimen against L. infantum, improving the reduction of parasite load in skin, lymph node and spleen. The analysis of immune markers in the spleen after challenge suggests that the trend to recover naïve levels of IFN-γ and IL-10, and the concurrent higher expression of NOS2, may be responsible for the protection induced by our vaccine co-administered with SIR.

Host Species Determines the Composition of the Prokaryotic Microbiota in Phlebotomus Sandflies

Phlebotomine sandflies are vectors of the humans' and mammals' parasite Leishmania spp. Although the role of gut microbiome in the biological cycle of insects is acknowledged, we still know little about the factors modulating the composition of the gut microbiota of sandflies. We tested whether host species impose a strong structural effect on the gut microbiota of Phlebotomus spp. Sandflies were collected from the island of Leros, Greece, and classified to P. papatasi, P. neglectus, P. tobbi, and P. similis, all being negative to Leishmania spp. The prokaryotic gut microbiota was determined via 16S rRNA gene amplicon sequencing. Phlebotomus species supported distinct microbial communities (p < 0.001). P. papatasi microbiota was the most distinct over-dominated by three Spiroplasma, Wolbachia and Paenibacillus operational taxonomic units (OTUs), while another Wolbachia OTU prevailed in P. neglectus. Conversely, the microbiota of P. tobbi and P. similis was composed of several less dominant OTUs. Archaea showed low presence with the dominant OTUs belonging to methanogenic Euryarcheota, ammonia-oxidizing Thaumarcheota, and Nanoarchaeota. We provide first insights into the composition of the bacterial and archaeal community of Phlebotomus sandflies and showed that, in the absence of Leishmania, host genotype is the major modulator of Phlebotomus sandfly gut microbiota.

Experimental assessment of permethrin-fipronil combination in preventing Leishmania infantum transmission to dogs under natural exposures

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Controlled experimental field study allowing natural exposure to sandflies.

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Two groups of 20 dogs each in two close sub-unit kennels.

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7/20 dogs infected by L. infantum in the untreated group.

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0/20 dogs infected by L. infantum in the fipronil-permethrin monthly treated group.

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100 % protection obtained during this one-year study.

Canine vector-borne disease transmission can be reduced with regular use of repellent insecticides. The objective of this year-long experimental study was to assess the efficacy of a topical formulation of fipronil/permethrin (Frontline Tri-Act®) in preventing transmission of Leishmania infantum by sandflies. This clinical field trial was conducted in Xanthi (Northern Greece), an area highly endemic for canine leishmaniosis, from April 2018 to March 2019. Forty purpose-bred Beagle dogs, testing negative for L. infantum prior to study initiation, were enrolled in the study, which consisted of three phases: Phase 1 (field exposure phase) took place from Day 0–196. The dogs were randomly allocated to two groups, group 1 (sham-treated topically with sterile water) and group 2 (treated topically with Frontline Tri-Act®). Dogs in both groups were housed in two subunits of an open-air kennel for a period of 7 months, spanning the Leishmania transmission season. All dogs were treated or sham-treated on Days 0, 28, 56, 84, 112, 140 and 168. Clinical examinations, PCR analysis of conjunctival swabs, and serological tests were performed on a monthly basis. Sandflies were collected every 2 weeks, during a 12 -h period overnight using light traps. Each collection was placed in a container and kept refrigerated until speciation and PCR analysis could be performed. In the second phase of the study, from Day 197 to 252, the dogs were moved into a protected environment (insect-proof protected environment phase). CDC light traps were activated every 2 weeks inside and outside the kennels to ensure the vector-free status of the facility. Monthly clinical examinations, including PCR analysis of conjunctival swabs, and serological tests continued. At the end of the phase 2, bone marrow samples were collected on all dogs. Phase 3 (the final post-winter check) took place from Day 253 to 350. Dogs were released and adopted by individual private owners on Day 253. Follow up analyses included blood collection for SNAP tests and conjunctival swaps for PCR analysis on Days 304 and 350. Additionally, bone marrow collections were also performed on Day 350.

Presence of sandflies was observed only in the phase 1 exposure period, and 1714 sandflies were collected (1427 females and 287 males). Two species were identified, Phlebotomus perniciosus var. tobbi and Phlebotomus neglectus. Out of the 62 pooled samples of sandflies assessed by PCR, three were considered positive (4.8 %). By the end of the study, 35 % of the Group 1 dogs (7/20) became positive based on PCR (conjunctival swab and bone marrow) and 30 % (6/20) based on SNAP/IFAT and ELISA tests, while all the dogs in the Frontline Tri-Act® treated group 2 remained negative for all tests (G1 vs G2, p = 0.008). All tests identified the same positive animals, and PCR allowed the detection of one additional infected dog. This clinical field trial demonstrated that monthly administration of Frontline Tri-Act® to dogs exposed to Leishsmania infection in a high endemic area provided 100 % preventive efficacy against transmission of L. infantum.

Feline Leishmania spp. Infection in a Non-Endemic Area of Northern Italy

Simple Summary

Leishmaniosis caused by Leishmania infantum is a parasitic disease of people and animals transmitted by sand fly vectors. Although dogs in south and central Italy are most affected, in recent decades feline leishmaniosis (FeL) has become an emerging disease. This study aimed to update information on the presence of FeL in stray cats in Milan, in northern Italy; to compare these results with previous studies performed in the same area; and to report aspects of Leishmania infection in cats. A total of 117 stray cats were included and 10 (8.6%) had L. infantum infection. The parasite was identified in popliteal lymph nodes in five cats and five had antibodies against L. infantum. Most infected cats were from a specific area of Milan. Increased gammaglobulins were seen in infected cats, which also had antibodies against the pathogens Anaplasma phagocytophilum, Chlamydophila felis, and Toxoplasma gondii. There was a high prevalence of FeL in the surveyed area of northern Italy. Further studies are needed to understand if these infected cats are being imported from other areas, or if there is a real Leishmania focus in Milan. Investigation of the presence of sand fly vectors in Milan would be useful.

Abstract

Feline leishmaniosis (FeL) is an emerging vector-borne feline disease, with increasing numbers of cases reported and studies performed internationally. This study aimed to update the epidemiological status for FeL in stray cats in Milan, northern Italy; compare these results with previous studies in Northern Italy; and report clinicopathologic findings and coinfections in cats infected with Leishmania spp. A total of 117 cats were tested for L. infantum and retrovirus infection, hematological, and biochemical parameters. Demographic and clinical data were collected and FeL affected cats screened for selected coinfections. Overall, 10/117 (8.6%) cats tested positive for L. infantum: in five cats L. infantum DNA was found in popliteal lymph nodes and five were IFAT seropositive at titers from 1:80 to 1:160. Infected cats were concentrated in a specific area of Milan (p = 0.0154). No specific clinicopathologic abnormalities or retroviral infections were significantly linked to the infection, other than hypergammaglobulinemia (p = 0.0127). Seroreactivity to Anaplasma phagocytophilum, Chlamydophila felis, and Toxoplasma gondii was found in some infected cats. A high prevalence of FeL was found in a non-endemic area of northern Italy and future studies should continually monitor this data to understand whether these cases are imported or if Leishmania vectors are present in this area.

Comparative evaluation of nucleic acid stabilizing reagents for RNA- and DNA-based Leishmania detection in blood as proxy for visceral burdens

BACKGROUND

Molecular detection techniques using peripheral blood are preferred over invasive tissue aspiration for the diagnosis and post-treatment follow-up of visceral leishmaniasis (VL) patients. This study aims to identify suitable stabilizing reagents to prevent DNA and RNA degradation during storage and transport to specialized laboratories where molecular diagnosis is performed.

METHODOLOGY

The stabilizing capacities of different commercially available reagents were compared using promastigote-spiked human blood and peripheral blood of Syrian golden hamsters subjected to experimental infection, treatment (miltefosine or aminopyrazole DNDi-1044) and immunosuppression. The impact of various storage temperature conditions was tested in combination with an established kinetoplast DNA (kDNA) qPCR and a recently developed spliced leader RNA (SL-RNA) assay for Leishmania detection.

PRINCIPAL FINDINGS

Irrespective of the blood type and stabilizer used, threshold (cT) values obtained with the SL-RNA qPCR were systematically lower than those obtained with the kDNA assay, confirming the advantage of the SL-RNA assay over the widely used kDNA assay for low-level Leishmania detection. Peripheral blood parasite levels correlated relatively well with hepatic burdens. RNA protect cell reagent provided the most optimal simultaneous DNA and RNA stabilization in both human and hamster blood. However, this stabilizer requires an erythrocyte lysis step, which can be challenging under field conditions. DNA/RNA shield provides a good alternative for downstream kDNA and SL-RNA assays, especially if sample storage capacity at 4 °C can be guaranteed.

CONCLUSIONS/SIGNIFICANCE

The recommended stabilizing reagents are compatible with RNA- and DNA-based Leishmania detection in peripheral blood in the VL hamster model and spiked human blood. Since molecular detection techniques using peripheral blood are less invasive than microscopic assessment of tissue aspirates, the findings of this study may be applied to human VL clinical studies.

Prevalence and incidence of vector-borne pathogens in unprotected dogs in two Brazilian regions

Background

Various vector-borne pathogens (VBPs) affect dogs worldwide, with their diversity and force of infection being usually higher in the tropics. Cross-sectional studies have been conducted to investigate the prevalence of VBPs in dogs, but data from longitudinal studies are scarce. Herein, we assessed the prevalence and the year-crude incidence (YCI) of Leishmania spp. and other VBPs in privately-owned dogs from two geographical regions of Brazil.

Methods

A total of 823 dogs were initially screened for Leishmania spp. by both serology and polymerase chain reaction (PCR). From the negatives, 307 (103 from São Joaquim de Bicas, Minas Gerais, and 204 from Goiana, Pernambuco) were randomly selected for the longitudinal study. These dogs were tested for various VBPs at baseline, after 8 and 12 months.

Results

Out of 823 dogs initially screened, 131 (15.9%) were positive for Leishmania spp. Out of the 307 dogs enrolled in the longitudinal study, 120 (39.1%) were lost for different reasons (e.g. animal death, owner decision, and lost to follow-up). In São Joaquim de Bicas, the baseline prevalence and YCI were as follows: 16.5% and 7.1% for Anaplasma spp.; 81.6% and 100% for Babesia spp.; 0% and 1.3% (only one faint positive) for Dirofilaria immitis; 37.9% and 22.9% for Ehrlichia spp.; 19.5% and 43.8% for Leishmania spp. In Goiana, the baseline prevalence and YCI were as follows: 45.1% and 38.3% for Anaplasma spp.; 79.9% and 96.0% for Babesia spp.; 36.3% and 39.8% for D. immitis; 64.7% and 58.5% for Ehrlichia spp.; 14.7% and 19.6% for Leishmania spp. Anti-Borrelia burgdorferi antibodies were not detected in any of the samples tested herein. The prevalence and YCI of Anaplasma spp., D. immitis and Ehrlichia spp. were significantly higher in Goiana. In contrast, the YCI of Leishmania spp. infection was significantly higher in São Joaquim de Bicas.

Conclusions

We confirmed a high prevalence and YCI of various VBPs among privately-owned dogs in two geographical regions of Brazil. Our data also indicate that the risk of infection varies significantly for individual VBPs and between the regions, which may be related to several factors that are still poorly understood.

Stray dogs in Nepal have high prevalence of vector-borne pathogens: a molecular survey

Background

Population of stray dogs is significant in large cities of Nepal, such as Kathmandu. Most of stray dogs suffer a lack of basic health care. Considering the clinical relevance, the broad distribution and the lack of information of canine vector borne diseases (CVBD) in Nepal, the aim of this study was to evaluate the prevalence of different vector-borne pathogens (VBP) in stray dogs living in the metropolitan area of Kathmandu, and to assess different traits as possible risk factors.

Methods

A total of 70 canine blood samples from stray dogs attended at the Kathmandu Animal Treatment Centre during August 2017 were collected on filter paper (Flinders Technology Associates (FTA) cards). Data regarding signalment, clinical signs and epidemiological characteristics were recorded for each animal. Real-time polymerase chain reaction assays were performed for Leishmania spp., Ehrlichia spp./Anaplasma spp., Babesia spp./Theileria spp. and Hepatozoon canis.

Results

The overall prevalence detected was 31.43% for Hepatozoon canis, 31.43% for Anaplasma platys, 27.14% for Ehrlichia canis, 18.57% for Leishmania donovani species complex, 12.86% for isolates corresponding to Theileria spp., 12.86% for Babesia vogeli and 2.86% for B. gibsoni. A total of 81.43% of the dogs were positive to at least one of the VBP tested. Co-infections were detected in 41.43% of the dogs. Dogs positive to any of the VBP tested, and particularly to E. canis, were older than those that were negative.

Conclusions

To our knowledge, this is the first molecular detection of VBP in stray dogs from Kathmandu, Nepal. The high prevalence of VBP detected highlights the need to implement a surveillance programme and control strategies for these CVBD in the population of stray dogs in this area.

Fast multiplex real-time PCR assay for simultaneous detection of dog and human blood and Leishmania parasites in sand flies

Background

The blood-feeding behaviour of female sand flies may increase their likelihood of acquiring and transmitting Leishmania parasites. Studies on the host usage by these insects may thus improve our understanding of the Leishmania transmission risk in leishmaniasis-endemic areas. Here, we developed a fast multiplex real-time PCR assay for simultaneous detection of dog, human and Leishmania DNA in sand flies.

Methods

Primers and TaqMan probes targeting the mitochondrial cytochrome c oxidase subunit 1 and cytochrome b genes of dog and human, respectively, were combined in a multiplex assay, which also includes primers and a TaqMan probe targeting the Leishmania minicircle kinetoplast DNA.

Results

The multiplex assay was 100% specific, with analytical sensitivities of 10³ fg/reaction for dog and human and 1 fg for Leishmania. By testing field-collected engorged female sand flies (95 Migonemyia migonei and two Nyssomyia intermedia), 50 M. migonei were positive for one or two targets (positivity rates: 45.4% for human, 4.1% for dog and 12.4% for Leishmania DNA).

Conclusions

This multiplex real-time PCR assay represents a novel fast assay for detecting dog, human and Leishmania DNA in female sand flies and therefore a tool for assessing the risk of Leishmania transmission to these hosts in areas of active transmission.

Canine vector-borne pathogens from dogs and ticks from Tamil Nadu, India

Canine vector-borne diseases (CVBDs) pose a major health problem in dogs globally, with the potential to cause zoonoses, in particular in developing countries where scientific knowledge on the topic is minimal. Blood samples and ticks were collected from stray dogs in Tamil Nadu, South India to assess the prevalence of CVBD-causing pathogens (Anaplasma spp., Babesia spp., Ehrlichia spp., Hepatozoon spp., filarioids and Leishmania spp.). Of the 230 dogs examined, 229 (99.6%) were infested by ticks (mean intensity, 5.65) with Rhipicephalus sanguineus sensu lato and Rhipicephalus haemaphysaloides being morphologically identified in the 98.3% and 1.7% of the infested dogs, respectively. Overall, the 67.8% (n = 156) of dogs was positive for at least one pathogen with Hepatozoon canis being the most prevalent (37.8%) followed by Anaplasma platys (22.6%), Ehrlichia canis (16.1%) Babesia vogeli (10%), Anaplasma phagocytophilum (0.4%) and Babesia gibsoni (0.4%). Two filarioids (Dirofilaria sp. "hongkongensis" and Brugia malayi, 0.4%) were diagnosed in sampled animals. Co-infection with H. canis and A. platys was the most prevalent (8.3%, P = 0.00001), whilst all animals scored negative for Leishmania spp.. Out of 295 ticks analysed, 215 R. sanguineus s.l. (75.4%) and 8 R. haemaphysaloides (88.9%) were positive for at least one pathogen with H. canis as the predominant species (42.5%), followed by A. platys (33.8%), E. canis (16.9%), B. vogeli (3.8%) and A. phagocytophilum (0.3%). Fifty-six dogs (35.9%) harboured the same pathogen as the respective tick specimens, while 29 dogs (18.6%) had a different pathogen. Thirteen sequence types (STs) were identified for H. canis, with ST2 (49.4%) as the most representative in dogs and ST1 (73.5%) in ticks. Similarly, seven STs were found for Anaplasma spp. (i.e., five for A. platys, one for A. phagocytophilum and one for Anaplasma sp.), with ST2 as the most representative in dogs (70.6%) and ST3 (52.5%) in ticks for A. platys. Only one ST was identified for B. vogeli, B. gibsoni, E. canis, D. sp. "hongkongensis" and B. malayi. Regular surveillance and adoption of adequate treatment and control measures are needed to reduce the risk of disease-causing pathogens in stray dogs and of pathogens with zoonotic potential.

Sterile or nonantibiotic-responsive pustular dermatitis and canine leishmaniosis: a 14 case series description and a statistical association study on 2420 cases

Background - No striking clinical and histopathological features of pustular dermatitis (PustD) in dogs suffering from canine leishmaniosis (CanL) have been identified; an association between CanL and PustD has not been demonstrated. Objectives - To characterize a series of dogs affected by CanL and pruritic PustD, and to evaluate a possible association between the two conditions. Conclusions - An association exists between PustD and CanL. At least in Leishmania-endemic areas, CanL should be ruled out before attempting an immunosuppressive treatment in dogs with PustD with the aforementioned characteristics. Staging of CanL through diagnostic procedures besides immunohistochemistry and PCR is recommended. Anti-leishmania treatment and short-to-medium courses of low-dose anti-inflammatory or immunomodulatory drugs are effective in controlling the clinical signs of PustD.

An appraisal of oriental theileriosis and the Theileria orientalis complex, with an emphasis on diagnosis and genetic characterisation

Oriental theileriosis, a tick-borne disease of bovids caused by members of the Theileria orientalis complex, has a worldwide distribution. Globally, at least 11 distinct genotypes of T. orientalis complex, including type 1 (chitose), type 2 (ikeda), type 3 (buffeli), types 4 to 8, and N1-N3, have been described based on the sequence of the major piroplasm surface protein (MPSP) gene. Of these 11 genotypes, mainly ikeda and chitose are known to be pathogenic and cause considerable morbidity (including high fever, anaemia, jaundice and abortion), production losses and/or mortality in cattle. Mixed infections with two or more genotypes of T. orientalis is common, but do not always lead to a clinical disease, posing challenges in the diagnosis of asymptomatic or subclinical forms of oriental theileriosis. The diagnosis of oriental theileriosis is usually based on clinical signs, the detection of piroplasms of T. orientalis in blood smears, and/or the use of serological or molecular techniques. This paper reviews current methods used for the diagnosis of T. orientalis infections and the genetic characterisation of members of the T. orientalis complex, and proposes that advanced genomic tools should be established for investigations of these and related haemoparasites.

Leishmaniasis in Norway Rats in Sewers, Barcelona, Spain

We detected Leishmania infantum in 98 Norway rats (Rattus norvegicus) trapped in parks and sewers of Barcelona, Spain. The 84 rats from the sewers showed a prevalence of 33.3% and up to 2,272 estimated parasites. These results, in the most abundant potential reservoir in cities, is of public health concern.

Clonality testing in the lymph nodes from dogs with lymphadenomegaly due to Leishmania infantum infection

INTRODUCTION

In southern European countries, multicentric lymphoma and leishmaniosis are the main differential diagnoses in dogs presented with generalized lymphadenomegaly. The cytological examination is in some cases inconclusive and polymerase chain reaction (PCR) for antigen receptor rearrangement (PARR) has become a common method to confirm or rule out a lymphoproliferative neoplasia. According to the literature, leishmaniosis may lead to clonal arrangements and therefore to a false diagnosis of lymphoma, but this assumption is made from a single leishmania infected dog. Therefore, the objective of this study was to prospectively evaluate results from PARR in dogs with lymphadenomegaly due to clinical leishmaniosis at the moment of diagnosis.

MATERIALS AND METHODS

31 dogs with a diagnosis of leishmaniosis based on the LeishVet guidelines were included in the study. Samples from enlarged lymph nodes were taken for cytological examination, clonality testing and Leishmania infantum PCR.

RESULTS

All 31 dogs had medium to high positive antibody titers against Leishmania spp. and 30/31 had a positive Leishmania PCR from the lymph node. A polyclonal arrangement for B cells (immunoglobulin heavy chain gene) and T cells (T-cell receptor gamma chain gene) antigen receptors was found in 28/31 dogs. Two out of 31 dogs showed a monoclonal arrangement for Ig with high (1:2) and low (1:7) polyclonal background respectively; and one of the 31 dogs showed a monoclonal arrangement for T cell receptor with low (1:3) polyclonal background.

CONCLUSION

Infections with Leishmania infantum resulted in clonal rearrangement, and therefore in a possible false diagnosis of lymphoma, in 3 out of 31 dogs (9.7%). Although, PARR is a useful method to differentiate lymphoma from reactive lymphoid hyperplasia in dogs with leishmaniosis, mono-/biclonal results should be interpreted carefully, especially in the presence of any degree of polyclonal background, and together with other clinicopathological findings.

Early antibody response and clinical outcome in experimental canine leishmaniasis

Infected dogs are the main reservoir of zoonotic visceral leishmaniasis, a widespread parasitic disease caused by Leishmania infantum. Therefore, the control of canine infections is required to reduce the incidence of human cases. Disease outcome in dogs depends on the fine balance between parasite virulence and efficacy of the immune system. Thus, knowledge of early response could yield relevant information for diagnosis and follow-up. In our study, 20 Beagle dogs were intravenously infected with 10⁸ amastigotes of a fresh isolate of L. infantum and monitored along 16 weeks post inoculation. Specific antibody response and clinical evolution of infected animals were highly variable. Immunofluorescence antibody test (IFAT) and enzyme linked immunosorbent assay (ELISA) were useful to assess infection status, although only ELISA with promastigote-coated plates and, particularly, western blotting (WB) allowed an early diagnosis. Prominent antigens were identified by mass peptide fingerprinting. Chaperonin HSP60, 32 and 30 KDa antigens were recognized by all dogs on week 10 post infection. This suggests that these antigens may be valuable for early diagnosis. Advanced infection showed, in addition, reactivity to HSP83 and HSP70. Disease outcome did not show a clear relationship with ELISA or IFAT titers. Correlation between the clinical status and the combined reactivity to some antigens sustains their use for diagnosis and follow-up.

Leishmania infantum in wild animals in endemic areas of southern Italy

Leishmania infantum infection in wildlife is increasingly reported in Europe, but scant data are available in Italy so far. This study aimed to investigate the circulation of L. infantum among sylvatic hosts in Sicily (southern Italy), a highly endemic area for canine leishmaniosis, through serological and molecular tools. Target tissues (skin, spleen, lymph nodes) collected from 71 European rabbits, 2 European hares, 7 red foxes, 11 European wildcats and 1 pine marten, were qPCR analysed for the detection of L. infantum DNA. Additionally, 40 rabbits, older than one year, were serologically screened for specific anti-Leishmania antibodies. Leishmania infantum was molecularly diagnosed in 5.4% (n = 5) of the examined animals (3/71 European rabbits, 2/7 red foxes). In many of the qPCR positive animals (4/5), the parasite DNA was more prevalent in visceral than cutaneous tissues. None of the positive animal showed signs of disease and/or macroscopic alterations of organs; low parasitic burden in all positive tissue samples was also recorded. Only one rabbit serum (i.e., 2.5%) tested positive for anti-Leishmania antibodies. The seropositive rabbit was in good health status and no amastigotes were observed in lymph-node aspirate and blood smears. This study provides first evidence of L. infantum infection in wild animals from Sicily (southern Italy). Despite the low prevalence of infection here reported, the circulation of the Leishmania in wild reservoirs in Sicily remains worthy of future investigations for a better understanding of their role in the epidemiology of the disease as well as to fine-tune control strategies in the area.

Assessment of histological liver alterations in dogs naturally infected with Leishmania infantum

Background

The liver plays a central role in the development of canine visceral leishmaniasis. Studies of natural infection in animals and humans indicate a direct relationship between resolution of infection and the formation and maturation of granulomas in the liver. However, in contrast to other reports in the literature, the present study found no differences in the characteristics of hepatic granulomas that could be related to resistance or susceptibility to Leishmania. Here, we describe the hepatic alterations observed in dogs with differing clinical manifestations of visceral leishmaniasis in an endemic area in the state of Bahia, Brazil.

Methods

We examined 148 animals in an endemic area. The animals were clinically examined, and the infection was determined by ELISA, spleen aspirate culture and quantitative PCR. The animals were grouped into asymptomatic or symptomatic based on the number of signs of LV. The histological liver evaluation was performed in a blinded way.

Results

Our results indicated no association between the characteristics of granulomas and clinical presentation. We found an association between the intensity of this inflammatory response and parasite load in the animals’ spleens. It is important to note that while hepatic alterations, such as portal and perivascular inflammation and the presence of larger amounts of granulomas, were linked with higher parasite loads, we found the inverse to be true with respect to intrasinusoidal lymphocytosis, the formation of intrasinusoidal inflammatory cell aggregates and Kupffer cell hypertrophy.

Conclusions

Our findings suggest that the presence of mononuclear inflammatory cells inside the sinusoids is more important than that of organized granulomas in terms of the containment of parasitism by the host. We suggest that the presence of granulomas indicates the failure of a first line of defense mechanism in the control of parasite infection, which could be related to the presence of inflammatory cells and Kupffer cell hypertrophy inside the sinusoids. We further demonstrated that dogs with active Leishmania spp. infection present a higher frequency of inflammatory changes in the liver. In addition to being correlated with the severity of clinical manifestation, these hepatic alterations were also associated with changes in hematological and biochemical parameters.

Molecular and serological survey of carnivore pathogens in free-roaming domestic cats of rural communities in southern Chile

Owned, free-roaming domestic cats are abundant in the Chilean countryside, having high probability of contact with wildlife and potentially participating as reservoirs of zoonotic pathogens. In the present study, 131 cats from two remote study areas (Valdivia and Chiloe Island) in southern Chile were analyzed for infection/exposure to eight pathogens. Serum samples from 112 cats were tested for antigens against feline leukemia virus (FeLV antigen-ELISA) and antibodies against feline immunodeficiency virus (FIV-ELISA) and canine distemper virus (CDV-serum neutralization), yielded occurrence of 8.9, 1.7 and 0.8% respectively. The presence of DNA of five vector-borne pathogens, piroplasmids, Ehrlichia spp., Anaplasma spp., Rickettsia spp. and Bartonella spp. was investigated in thirty cats. Overall observed occurrence was 6.6% (2/30) for both Anaplasma platys, and B. henselae, and 3.3% (1/30) for both Bartonella sp. and Theileria equi. Observed occurrence for all vector-borne pathogens in Valdivia area was significantly higher than in Chiloe Island (5/15 vs 0/15; P=0.04). Our results represent the first description of exposure to CDV and DNA detection of T. equi and A. platys in domestic cats in Chile. The results highlight the importance of performing pathogen screening in owned, free-roaming rural cats to evaluate their potential role as reservoirs of infection and vectors for disease transmission to wildlife.

Immunohistochemical and Molecular Diagnosis of Mucocutaneous and Mucosal Leishmaniasis

Leishmaniasis is a parasitic infection transmitted by the bite of infected female sandflies. It principally affects the skin, and the frequency of mucosal involvement is about 5% to 20%. Considering the rarity of leishmaniasis affecting the upper aerodigestive tract mucosa, we evaluated the characteristics of mucocutaneous leishmaniasis and mucosal leishmaniasis and the diagnostic difficulty when the parasites are scarce in tissue samples. The clinical, histopathological, histochemical, immunohistochemical, and molecular features of 17 cases of mucocutaneous leishmaniasis and mucosal leishmaniasis were assessed. Mucosal disease was principally found in the soft palate, oropharynx, and nose, manifesting mainly as a solitary ulcer. In hematoxylin and eosin-stained sections, 10 cases revealed abundant amastigotes within the macrophages. Giemsa staining was not shown to be helpful to confirm the diagnosis in 6 cases with scarce or nondetectable amastigotes. Immunohistochemistry (IHC) showed high sensitivity by positive staining in 14 out of 17 cases (82.3%). Polymerase chain reaction was shown to be more sensitive than IHC with 13 out of 14 (92.8%) positive cases, including the 3 IHC negative cases; however, this technique is not available in many endemic regions. In summary, we suggest that the IHC is a simple technique with rapid results and relatively low cost, when compared with other laboratorial procedures; thus, IHC is a helpful tool that should be implemented in the routine diagnosis of leishmania.

Genetic diversity and phylogenetic relationships between Leishmania infantum from dogs, humans and wildlife in south-east Spain

Leishmania infantum causes human and canine leishmaniosis. The parasite, transmitted by phlebotomine sand flies, infects species other than dogs and people, including wildlife, although their role as reservoirs of infection remains unknown for most species. Molecular typing of parasites to investigate genetic variability and evolutionary proximity can help understand transmission cycles and designing control strategies. We investigated Leishmania DNA variability in kinetoplast (kDNA) and internal transcribed spacer 2 (ITS2) sequences in asymptomatically infected wildlife (n = 58) and symptomatically and asymptomatically infected humans (n = 38) and dogs (n = 15) from south-east Spain, using single nucleotide polymorphisms (SNPs) and in silico restriction fragment length polymorphism (RFLP) analyses. All ITS2 sequences (n = 76) displayed a 99%-100% nucleotide identity with a L. infantum reference sequence, except one with a 98% identity to a reference Leishmania panamensis sequence, from an Ecuadorian patient. No heterogeneity was recorded in the 73 L. infantum ITS2 sequences except for one SNP in a human parasite sequence. In contrast, kDNA analysis of 44 L. infantum sequences revealed 11 SNP genotypes (nucleotide variability up to 4.3%) and four RFLP genotypes including B, F and newly described S and T genotypes. Genotype frequency was significantly greater in symptomatic compared to asymptomatic individuals. Both methods similarly grouped parasites as predominantly or exclusively found in humans, in dogs, in wildlife or in all three of them. Accordingly, the phylogenetic analysis of kDNA sequences revealed three main clusters, two as a paraphyletic human parasites clade and a third including dogs, people and wildlife parasites. Results suggest that Leishmania infantum genetics is complex even in small geographical areas and that, probably, several independent transmission cycles take place simultaneously including some connecting animals and humans. Investigating these transmission networks may be useful in understanding the transmission dynamics, infection risk and therefore in planning L. infantum control strategies.

Natural infection by Leishmania infantum in the Lutzomyia longipalpis population of an endemic coastal area to visceral leishmaniasis in Brazil is not associated with bioclimatic factors

Visceral leishmaniasis (VL) is a zoonosis caused by the protozoan Leishmania infantum and in Brazil is transmitted mainly by the bite of Lutzomuyia longipalpis sand flies. Data about the presence, distribution, natural infection rate, seasonal and monthly dynamics of the vector population are important for optimizing the measures to control VL in endemic areas. This study aimed to identify sand fly fauna in an endemic area for VL to detect the prevalence of L. infantum infection in the Lu. longipalpis population and to elucidate the influence of bioclimatic factors on the monthly fluctuations of this vector. HP light traps were monthly set in the intradomicile and peridomicile of residences located in the central and beachfront areas of Camaçari, a VL endemic area. The sand fly collection was conducted in two periods: i) period 1-between December 2011 and November 2012 and ii) period 2-August 2014 and July 2015. Sand fly species were identified and detection of L. infantum infection by qPCR was performed in pools of female Lu. longipalpis. For the first time, the parasite load of positive pools was correlated with the number of Lu. longipalpis captured per month in both periods. Correlation analyses between the monthly fluctuation of the sand fly population and bioclimatic indices of the municipality in both collection periods were also performed. In both evaluated periods, more than 98% of the collected sand flies were Lu. longipalpis, confirming the predominance of this species in the region. It was captured mostly in the beachfront area in all months evaluated (99%). For the period 1, Leishmania DNA was detected in 81% of tested pools representing a minimal infection rate of 9.6%. In the period 2, 40% of the pools were positive with a minimal infection rate of 10.2%. Infected sand flies were only detected in the beachfront area in both periods. The parasite load was low and did not vary in the evaluated months despite the number of collected sand flies. No correlation was observed for climatic factors in both areas of Camaçari. These findings emphasize the high risk of Leishmania transmission in Camaçari regardless of the season and that other factors, aside from bioclimatic elements, are influencing the sand fly population monthly fluctuation.

Molecular xenomonitoring and host identification of Leishmania sand fly vectors in a Mediterranean periurban wildlife park

The epidemiological cycle of zoonotic phlebotomine-borne Leishmania infantum is a complex system in which domestic animals and wildlife interact and participate in its maintenance and transmission. In this study, we combined entomological surveillance, xenomonitoring of L. infantum and identification of host feeding sources of engorged females to investigate the potential contribution of a periurban wildlife park to leishmaniosis in neighbouring residential areas. Overall, 7,309 sand flies were collected in 111 trap-days during the summers of 2016-2018 in an endemic area in south-east Spain. Five different sand fly species were captured, with Phlebotomus perniciosus, the main L. infantum vector in this region, representing the most common species. Sand fly distribution was spatially heterogeneous in terms of species, sexes and female physiological stage (unfed, gravid and engorged females) and related to host distribution and management, and environmental features. None of the 602 sand flies analysed for L. infantum infection by kinetoplast real-time PCR were positive. We used molecular tools to identify the vertebrate hosts of sand flies and identified 17 host species, mainly mammals. Human DNA was not identified in engorged sand flies. This study provides evidence that wildlife parks in south-east Spain are ideal grounds for sand fly vectors but do not necessarily increase L. infantum infection risk to humans and dogs living in surrounding residential areas. This is probably because vectors feed mostly on non-L. infantum competent hosts and this should be investigated for a better understanding of the contribution of wildlife parks to the local epidemiology of L. infantum.

A pathological study of Leishmania infantum natural infection in European rabbits (Oryctolagus cuniculus) and Iberian hares (Lepus granatensis)

In this study, we describe the pathology of Leishmania infantum infection in naturally infected wild Leporidae and compare diagnosis of infection using histopathology, direct fluorescent antibody (DFA) assay, immunofluorescence antibody test (IFAT) and quantitative real-time PCR (qPCR). Tissues were analysed from 52 European rabbits (Oryctolagus cuniculus) and 7 Iberian hares (Lepus granatensis) from the Community of Madrid (Spain). Our results show that L. infantum infection is associated with only minimal histopathological lesions and that L. infantum amastigotes can be detected by DFA assay in all tissues types tested, including skin. These results were confirmed by qPCR on fresh frozen tissues in 13% of rabbits and 100% of hares. However, L. infantum DNA could not be detected by qPCR on paraffin-embedded tissue obtained by laser capture microdissection. Using the DFA assay to diagnose L. infantum, infection may provide further insights into this disease in wild animals and may allow the precise tissue localization of L. infantum, thereby guiding follow-up tests with more accurate qPCR.

A nationwide survey of Leishmania infantum infection in cats and associated risk factors in Italy

Though scantly investigated, Leishmania infantum infection and clinical cases of leishmaniasis in cats have been recently reported in several countries of the Mediterranean basin, with large variability in prevalence data. A major limitation in the comparability of the data available is attributed to the differences in diagnostic techniques employed and cat populations sampled. The aim of this study was to assess the prevalence of L. infantum infection in owned cats across Italy by serological and molecular tests and the identification of potential risk factors. Blood samples from 2,659 cats from northern (n = 1,543), central (n = 471) and southern (n = 645) Italy were tested for antibodies against L. infantum, by an immunofluorescence antibody test and for the parasites’ DNA, by real-time PCR. Samples were additionally screened for feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) proviral DNAs. An overall cumulative L. infantum prevalence of 3.9% was recorded by serology (3.3%) and/or qPCR (0.8%), with a higher rate (10.5%) in southern Italy. The risk of L. infantum infection in cats was significantly associated to the geographical areas (South vs North and Centre; p<0.0001), age class (from 19 months to 6 years old vs ≤18 months old, p = 0.0003), neutering status (not neutered vs neutered, p = 0.0028) and FIV infection (p = 0.0051).Though the role of cats in the epidemiology of L. infantum is still debated, our findings indicate that cats are exposed to and/or infected by this protozoan, mainly in endemic regions of Italy. Hence, a standardization of procedures for a prompt diagnosis of L. infantum infection in cats and for screening cat population is crucial for a better understanding of the epidemiology of feline leishmaniasis, and of the potential role of cats in the transmission cycle of zoonotic visceral leishmaniasis.

Zoonotic visceral leishmaniasis is a potentially fatal parasitic disease, which is caused by Leishmania infantum. Its distribution is associated with the occurrence of the sand fly vectors and reservoir hosts. Since L. infantum infection can occur in cats with clinical or subclinical outcomes, the role of cats in the epidemiology of zoonotic visceral leishmaniasis needs to be thoroughly assessed. This study aimed to evaluate the prevalence and associated risk factors for infection with L. infantum in a large subset of cats across Italy, a known endemic area with records of human cases of visceral leishmaniasis. Serum and blood samples from 2,659 cats from northern (n = 1,543), central (n = 471) and southern (n = 645) Italy were tested for antibodies against L. infantum and parasites’ DNA, respectively. A cumulative L. infantum prevalence of 3.9% was recorded by serology (3.3%) and/or real-time PCR (0.8%). The risk of L. infantum infection in cats was associated to the geographical areas, age class, neutering status and feline immunodeficiency virus infection. These findings reveal that cats are exposed to and/or infected by this protozoan across the country, warranting further investigation to assess their role in the epidemiology of zoonotic visceral leishmaniasis to refine surveillance and prevention strategies against this veterinary and medically important ailment.

Retrospective analysis of vector-borne infections in dogs after travelling to endemic areas (2007-2018)

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There is a risk even for dogs with limited time of exposure to obtain a vector-borne infection.

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Prevention of vector-transferred pathogens in dogs travelling to endemic areas is important.

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The owners should be educated regarding the vectors, diseases, risks and prophylaxis.

Canine vector-borne infections gained in importance in Germany due to growing tourist traffic, the increased import of dogs from abroad and the changing of climatic conditions. The Mediterranean region and southeastern Europe are geographical areas where pathogens such as Leishmania (L.) infantum, Hepatozoon (H.) canis, Ehrlichia (E.) canis, Anaplasma (A.) platys and Dirofilaria (D.) spp. are endemic. Meanwhile, Babesia (B.) spp. and A. phagocytophilum are present in central and western Europe. The objective of this retrospective study was to evaluate whether dogs were exposed to a corresponding risk of infection when travelling to regions in the Mediterranean area and southeastern Europe, which are endemic for these pathogens.

Medical records and laboratory test results of 303 dogs that travelled to 14 countries endemic for the mentioned canine vector-borne pathogens and that were presented to the Small Animal Clinic at Freie Universität Berlin between 2007 and 2018 were retrospectively reviewed. A total of 1174 test results from external laboratories were descriptively analysed including 525 test results of direct and 649 of indirect determination methods.

Overall, 13% of the tested dogs (40/303) were positive for at least one pathogen. Concurrent infections with two pathogens were detected in 1% of the dogs (4/303). The positive results were: E. canis 8% (18/231 dogs; Polymerase chain reaction [PCR] 3/73, indirect immunofluorescence test [IFAT] 18/209 dogs), L. infantum 5% (14/260 dogs; PCR 5/80, IFAT or enzyme linked immunosorbent assay [ELISA] 11/251 dogs), Babesia spp. 5% (11/232 dogs; Babesia spp. PCR 3/127, B. canis/vogeli IFAT or ELISA 8/160, B. gibsoni IFAT 2/22), Dirofilaria spp. 1% (1/133 dogs; D. immitis antigen-ELISA 1/117, microfilariae PCR 0/16, Knott´s test 0/69 dogs). None of the dogs has been tested positive in a combined Babesia spp./Hepatozoon spp. PCR test (0/15 dogs) and for H. canis (0/17 dogs; PCR) or A. platys (0/11 dogs; PCR).

There is a substantial risk for dogs travelling to areas endemic for vector-borne pathogens even with limited time of exposure to get infected. The data indicates the importance of owner education and prophylactic measurements against vector-borne infections in dogs travelling to endemic areas.

Molecular detection of Leishmania infantum DNA according to clinical stages of leishmaniasis in dog

The aim of this study was to compare molecular tests used to diagnose Leishmania spp. in dogs with different stages of infection. Blood and conjunctival swab (CS) samples from dogs classified in four clinical stages were subjected to different PCR protocols (13A/13B, MC1/MC2, LITSR/L5.8S and LEISH-1/LEISH-2 primers). To the study, 22.3% (48/215) of dogs were classified as without clinical signs, 67.5% (145/215) stage I (mild disease), 7.0% (15/215) stage II (moderate disease) and 3.2% (7/215) stage III (severe disease). The results showed that in blood samples, 13A/13B detected a significant higher number of positive dogs in stage I (25/145) and in total (42/215) (p≤0.05). However, when CS samples were tested, no difference was observed (p>0.05). On the other hand, in blood samples, MC1/MC2 detected significantly fewer positive dogs classified as without clinical signs (0/48), in stage I (0/145) and in total (1/215) (p≤0.05). Likewise, in CS samples, this primers showed also lower detection (1/215) (p≤0.05). So than, we can conclude that PCR on blood samples with 13A/13B primers has greater capacity to detect positive dogs, mainly at the initial of clinical disease than do other primers and MC1/MC2 are not a good choice to detect Leishmania infantum infection in dogs.

Diagnostic performance of a qPCR for Leishmania on stained cytological specimens and on filter paper impressions obtained from cutaneous lesions suggestive of canine leishmaniosis

BACKGROUND

Detection of Leishmania in cutaneous lesions is possible by visualization of amastigotes. Detection of Leishmania DNA by PCR presents greater sensitivity, and PCR has been used to diagnose cutaneous leishmaniosis in humans using noninvasive clinical specimens.

OBJECTIVES

Study I: to determine if Leishmania DNA could be efficiently extracted and amplified from archived Diff-Quik^® -stained slides of cytological specimens from canine cutaneous lesions. Study II: to evaluate the diagnostic performance of a Leishmania-quantitative (q)PCR on stained cytological specimens and on filter paper impressions (FPI) obtained from cutaneous lesions suggestive of canine leishmaniosis (CanL).

ANIMALS

Samples from cutaneous lesions of 54 dogs.

METHODS AND MATERIALS

Study I: Leishmania-qPCR was performed on 19 glass slides (from nine dogs) with cytologically visible amastigotes. Fifteen slides with no visible amastigotes, obtained from 12 dogs seronegative for Leishmania by ELISA, served as controls. Study II: Leishmania-qPCR was performed on glass slides and FPI from cutaneous lesions compatible with clinical leishmaniosis in 33 dogs.

RESULTS

Study I: all slides with visible amastigotes had positive qPCR, whereas all control slides yielded negative results. Study II: of 13 dogs definitively diagnosed with clinical leishmaniosis, eight had visible amastigotes on cytology, whereas Leishmania-qPCR was positive on 11 glass slides and 13 FPI. Leishmaniosis was ruled out by standard methods in 20 dogs, four of which yielded positive qPCR on FPI and/or glass slides.

CONCLUSIONS AND CLINICAL IMPORTANCE

Leishmania-DNA can be detected efficiently by qPCR from cutaneous cytological specimens and FPI to diagnose Leishmania infection in dogs with cutaneous lesions suggestive of CanL.

An investigation of polymorphisms in innate and adaptive immune response genes in canine leishmaniosis

The outcome of infection with Leishmania infantum in dogs is variable, which is thought to be due to the nature of the immune response mounted by the host. As a consequence, the clinical signs and severity of canine leishmaniosis vary between individual dogs. Host immunogenetic factors might play an important role in determining the outcome of infection. The aim of this study was to examine polymorphisms in innate and adaptive immune response genes, to determine whether any of these were associated with susceptibility or resistance to L. infantum infection. Genomic DNA was obtained from two groups: pet dogs in endemic regions of Europe and a group of Beagles exposed to sand fly infection as part of a vaccine study. Genotyping was performed using a SNP (single nucleotide polymorphism) array for selected immune response genes. The first part of the study compared 62 clinical cases with 101 clinically unaffected dogs that were seronegative for Leishmania antibodies. One SNP in the CIITA gene demonstrated a significantly higher minor allele frequency in the case group, compared with the control group at the individual SNP level after permutation, but was not significant after correction for multiple testing. The second part of the study examined 48 Beagle dogs exposed to L. infantum over two transmission seasons. Twenty-seven dogs with a resistant phenotype (no evidence of clinical disease, seronegative at the end of the study period, negative on lymph node culture and only transiently PCR positive in bone marrow) were compared with 21 dogs demonstrating a susceptible phenotype (clinical disease, seropositive, positive lymph node culture and consistently PCR positive in bone marrow). Three SNPs in TLR3, two SNPs in PTPN22 and one SNP in TLR4 and IL1A were associated with the susceptible phenotype in the Beagle group at the individual SNP level after permutation analysis, but were not significant after correction for multiple testing. Further validation of these SNPs is required in a larger cohort of dogs, ideally with extreme phenotypes to confirm an association with the outcome of L. infantum infection.

Treatment and long-term follow-up of a cat with leishmaniosis

BACKGROUND

Leishmania infection in cats is being increasingly reported in endemic areas. Nevertheless, only a few clinical cases have been described in cats, and even fewer have provided information on the response to treatment and a proper follow-up. Here we report a case of feline leishmaniosis not associated with any other disease or co-infection and document its response to allopurinol treatment and long-term follow-up data.

RESULTS

A 6-year-old domestic shorthair female cat was referred for nodular blepharitis, mucocutaneous ulcerative lesions of the mouth and lymph node enlargement. The cat was moderately anaemic, hyperglobulinaemic and tested negative for feline leukaemia virus and feline immunodeficiency virus. Fine needle aspirates of nodules and mucocutaneous lesions showed the presence of numerous amastigote forms of Leishmania. Leishmania infection was further confirmed by serology (IFAT test, 1:640) and real-time PCR (RT-PCR) on blood and conjunctival swabs. The cat was treated with allopurinol (20 mg/kg SID), which was clinically effective, although the cat remained Leishmania-positive in serology and RT-PCR on blood and conjunctival swabs. Allopurinol treatment was interrupted after seven months because of the healing of all lesions and lack of compliance by the owner. After two years, the cat relapsed displaying almost the same clinical signs and clinicopathological alterations. On this occasion, the parasite was isolated by culture and identified as belonging to L. infantum. Allopurinol treatment was started again but was interrupted several times because of the itching side effect observed. The cat worsened progressively and died two months after the relapse without any chance to shift the treatment to another molecule (e.g. meglumineantimoniate or miltefosine).

CONCLUSIONS

Out of all documented cases of feline leishmanosis, the present case has the longest follow-up period and it is one of the few in which the parasite was isolated and identified. It further confirms the potential progression of Leishmania infection to disease in cats even in the absence of comorbidities. Veterinarians practicing in endemic areas should be aware of this susceptibility, properly include feline leishmaniosis in the differential diagnosis and propose preventative measures to those cats at risk.

Home sweet home: sand flies find a refuge in remote indigenous villages in north-eastern Brazil, where leishmaniasis is endemic

BACKGROUND

From 2012 to 2013, an outbreak of cutaneous leishmaniasis by Leishmania braziliensis was detected in indigenous villages located in a remote rural area of Pernambuco state, north-eastern Brazil. Considering that the principal activities of this indigenous community are farming and crop plantation, and also that the outbreak involved many children, we investigated the presence of sand fly vectors inside human houses and also the exposure of dogs to leishmanial parasites. Our general objective was to gather epidemiological data that could indicate the occurrence of a peri-domestic/domestic transmission cycle of L. braziliensis in these indigenous villages.

METHODS

From March 2015 to March 2016, sand flies were collected using light traps in the indoor and immediate outdoor environments in the three indigenous villages that reported the most cutaneous leishmaniasis cases during the 2012-2013 outbreak. Moreover, samples obtained from 300 dogs living in the outbreak villages and two nearby villages were tested by a rapid immunochromatographic test and by a real-time PCR for detecting anti-Leishmania antibodies and Leishmania DNA, respectively.

RESULTS

In total, 5640 sand flies belonging to 11 species were identified. Males (n = 3540) predominated over females (n = 2100). Migonemyia migonei (84.3%) was the most abundant species, followed by Evandromyia lenti (5.5%), Lutzomyia longipalpis (4.1%), Nyssomyia intermedia (1.6%) and Micropygomyia capixaba (1.4%), representing together ~97% of the sand flies collected. Nine out of the 11 species identified in this study were found indoors, including M. migonei, L. longipalpis and N. intermedia, which are proven vectors of Leishmania spp. Out of 300 dogs tested, 26 (8.7%) presented anti-Leishmania antibodies and six (2%) were Leishmania DNA-positive. The level of exposure in dogs living in the indigenous villages where the 2012-2013 outbreak of human CL was detected was almost 2-fold higher than in the two nearby villages (11.0 vs 6.2% for serology and 2.6 vs 1.4% for real-time PCR).

CONCLUSIONS

The results suggest that different sand fly vectors may be adapted to human dwellings, thus increasing the risk of transmission in the indoor and immediate outdoor environments. The adaptation of sand flies to the indoor environment in the studied indigenous villages may be partly explained by the poor housing conditions and the proximity of the houses to crop plantations and forest fragments.

Molecular detection of Leishmania spp. in dogs and a cat from Doha, Qatar

Background

Canine and feline leishmanioses are increasingly reported worldwide and represent a threat to both animal and human health. Despite their relevance, data about leishmanioses in companion animals in the east-central part of the Arabian Peninsula are unavailable. Therefore, we investigated the occurrence of Leishmania spp. in dogs and cats from Qatar.

Methods

From March 2016 to May 2018, 199 pets (120 dogs and 79 cats) living in Doha or its outskirts were included in this study. From each animal a blood sample was collected and tested for Leishmania spp. by quantitative real-time PCR.

Results

Out of the 199 animals, four (2.0%) were positive for Leishmania spp., including three dogs (2.5%) and one cat (1.3%).

Conclusions

All positive animals were born in Qatar and had not travelled overseas, suggesting that infection was locally acquired. Considering the occurrence of Leishmania spp. and its potential impact on the health of animals and humans, it is crucial to increase scientific knowledge in order to plan screening and regular prophylaxis against sand fly vectors to reduce the risk of infection.