Characterization of Leishmania infantum strains in blood samples from infected dogs and humans by PCR-RFLP

Meteorological, demographic, and environmental risk factors for Leishmania infantum in wildlife

Leishmania infantum is an important and neglected vector-borne zoonotic protozoa endemic in the Mediterranean basin. Several wild and domestic mammals can contribute to maintaining its circulation but their importance as effective reservoirs is still under discussion and varies depending on local ecological communities. By combining environmental, climatic, and individual information, this study assessed the presence of L. infantum DNA in a set of wild species from Northwestern Italy and the potential ecological factors related to the risk of infection. From 2020 to 2022, 304 free-ranging wild animals were analyzed for the detection of L. infantum DNA in the spleen and popliteal lymph node (when available). The prevalence obtained in wild boar (Sus scrofa) and roe deer (Capreolus capreolus) was higher than those previously reported (% ± confidence interval 95%; 42.9 ± 18.4% and 27 ± 6.6% in wild boar and roe deer, respectively), and this is the first report of this parasite infecting the coypu Myocastor coypus (60 ± 34.7%). L. infantum DNA was detected in all the seasons including those free of adult sandflies and seasonal differences were minimal, suggesting a long course of infection. The models revealed that animals from rainy areas with higher greenness during the summer, highly populated by humans and predominantly covered by water surfaces had a higher risk of L. infantum. This study contributes to confirming previous findings on the existence of a sylvatic cycle for L. infantum in certain regions of Italy, as well as on the potential epidemiological role of roe deer for this parasite given the elevated prevalence found.

Typing of Leishmania isolates from vectors and leporids of the Madrid (Spain) outbreak

In 2009, a large outbreak of leishmaniasis, associated with environmental changes, was declared near Madrid (Spain), in which Phlebotomus perniciosus was the vector, whereas the main reservoirs were hares and rabbits. Analysis of isolates from humans, vectors and leporids from the focus identified the Leishmania infantum ITS-Lombardi genotype. However, multilocus enzyme electrophoresis (MLEE), the reference technique for Leishmania typing, and sequencing of the hsp70 gene, a commonly used marker, were not performed. In the present study, 19 isolates from P. perniciosus (n = 11), hares (n = 5) and rabbits (n = 3) from the outbreak area, all characterized as ITS-Lombardi in previous studies, were analysed by MLEE and hsp70 sequencing. The hsp70 results confirmed that all the analysed strains are L. infantum. However, by MLEE, 4 different zymodemes of L. infantum were identified based on variable mobilities of the NP1 enzyme: MON-34 (NP1100, n = 11), MON-80 (NP1130, n = 6), MON-24 (NP1140, n = 1) and MON-331 (NP1150, n = 1). The relative frequency of these zymodemes does not correspond to their usual occurrence in Spain. Moreover, MON-34 and MON-80 were found in P. perniciosus, hares and rabbits for the first time. These findings continue to provide insights into the outbreak and call for further studies with a higher number of strains.

Zoonotic Microparasites in Invasive Black Rats (Rattus rattus) from Small Islands in Central Italy

Invasive species have a detrimental impact on native populations, particularly in island ecosystems, and they pose a potential zoonotic and wildlife threat. Black rats (Rattus rattus) are invasive species that disrupt native flora and fauna on islands and serve as potential competent reservoirs for various pathogens and parasites. Microparasites screening was conducted in rat populations from small islands in central Italy (the Pontine Islands and Pianosa) with the aim of assessing the role of rats in maintaining infections, particularly in cases where key reservoir hosts were scarce or absent. We focused on microparasites of zoonotic and veterinary relevance. A total of 53 rats was kill-trapped and target tissues were analysed with molecular techniques. We observed the absence or very low prevalence of Anaplasma spp., while Babesia was found in rats from all locations, marking the first recorded instance of Babesia divergens in wild rats. Data from Pianosa strongly suggest the presence of an autochthonous Leishmania infantum cycle in the Tuscan archipelago islands. Neospora caninum was absent from all islands, even in areas where dogs, the main reservoirs, were present. Toxoplasma gondii was only recorded on the Pontine Islands, where genotyping is needed to shed light on infection dynamics. This study confirms that invasive species, such as rats, may be responsible for maintaining an increased parasitological threat to fauna and human communities in certain ecosystems.

LIMITATION OF PRIMERS USED IN PCR FOR THE CHARACTERIZATION OF LEISHMANIA INFANTUM

Conventional PCR provides Leishmania species characterization with even a small amount of biological material. Species-specific primers have been a widely used alternative; however, nonspecific amplifications are a reality, interfering with PCR efficiency. In endemic areas with multiple etiological agents for leishmaniasis, there is a requirement for higher specificity of primers. This study evaluates 3 pairs of primers described for the identification and characterization of Leishmania infantum. Primers RV1/RV2, LEISH1/LEISH2, and FLC2/RLC2 were used with the DNA of L. infantum, Leishmania amazonensis, and Leishmania braziliensis. An initial temperature curve was performed (52-62 C) to determine the optimal annealing temperature, followed by a dilution curve of Leishmania DNA (500 pg/μl, 50 pg/μl, 5 pg/μl, 500 fg/μl, 50 fg/μl, 5 fg/μl, and 0.5 fg/μl) to be used for analytical sensitivity. RV1/RV2 PCR amplified L. infantum and L. amazonensis at all analyzed temperatures; LEISH1/LEISH2 PCR amplified all 3 species of Leishmania, although at some temperatures L. infantum was specifically amplified, and, finally, FLC2/RLC2 PCR amplified only L. infantum at all temperatures analyzed. In terms of sensitivity, RV1/RV2 PCR detected 1 fg of L. infantum DNA and 100 pg of L. amazonensis DNA; LEISH1/LEISH2 PCR detected 1 fg of L. infantum DNA, 100 fg of L. amazonensis DNA, and 10 fg of L. braziliensis DNA; and FLC2/RLC2 PCR detected 10 fg of L. infantum DNA. Thus, PCR with FLC2/RLC2 primers is best suited for the molecular characterization of L. infantum, especially in areas where there is an incidence of more than 1 Leishmania species, such as South America.

Genetic Diversity and Population Structure of Leishmania infantum in Morocco as Revealed by Multilocus Sequence Typing (MLST) Approach

Leishmania infantum is endemic in Morocco, and it causes both visceral (VL) and cutaneous leishmaniasis (CL). In this study, the multilocus sequence typing (MLST) approach was used to investigate the phylogeny and population structure of Leishmania infantum strains isolated from CL and VL patients and the canine reservoir in different leishmaniasis endemic foci in Morocco. For this purpose, eight loci (pgm, alat, me, fh, g6pd, pgd, gpi and cytb) were amplified in 40 samples, out of which 31 were successfully sequenced. The genetic diversity analysis detected a high degree of intraspecific genetic variability among the studied strains. The phylogenetic and the haplotype analyses showed that most of the strains from the same geographical areas clustered together. The recombination among Leishmania infantum strains was revealed through a splits tree analysis and the number of recombination events. Moreover, the assessment of the gene flow between Leishmania infantum and Leishmania tropica through phylogenetic analysis and haplotype diversity in two endemic foci where the two species were sympatric showed no genetic exchange between the two species.

Feline Leishmaniosis in Northwestern Italy: Current Status and Zoonotic Implications

Leishmaniasis remains one of the major neglected tropical diseases. The epidemiological profile of the disease comprises a wide range of hosts, including dogs and cats. Despite several studies about feline Leishmaniosis, the role of cats in disease epidemiology and its clinical impact is still debated. The present study raises awareness about the impact of leishmaniasis in cats from an endemic region in of Northwestern Italy (Liguria). A total number of 250 serum and 282 blood samples were collected from cats, then assessed for Leishmania infantum (L. infantum) serologically using western blot (WB) and molecularly using polymerase chain reaction (PCR). We also tested the association of Leishmania infection with some infectious agents like haemotropic Mycoplasma, Feline immunodeficiency virus (FIV) and Feline leukemia virus (FeLV) together with the hematobiochemical status of the examined animals. Interestingly, all tested animals were asymptomatic and out of 250 examined serum samples, 33 (13.20%) samples (confidence interval (CI) 95% 9.56-17.96%) were positive at WB for L. infantum, whereas of the 282 blood samples, 80 (28.36%) returned a positive PCR (CI 95% 23.43-33.89%). Furthermore, there was a statistical association between PCR positivity for L. infantum and some hematological parameters besides FIV infection as well as a direct significant correlation between Mycoplasma infection and WB positivity. Taken together, the present findings report high prevalence of L. infantum among cats, which reinforces the significance of such positive asymptomatic animals and confirms the very low humoral response in this species. In addition, the laboratory values provide evidence that infection by the parasite is linked to alteration of some hematological parameters and is correlated to some infectious agents. These data are of interest and suggest future research for accurate diagnosis of such zoonosis.

Molecular Survey on Vector-Borne Pathogens in Alpine Wild Carnivorans

In Europe, free-ranging wildlife has been linked to the emergence of several vector-borne diseases such as rodents for Borrelia burgdorferi s.l. In particular, wild carnivorans are one of the most important sources of emerging zoonotic pathogens worldwide, although little information is available regarding the epidemiology of vector-borne parasites in these animals. Thus, the aim of this paper was to investigate the prevalence of Babesia spp., Anaplasma spp., Ehrlichia spp., Hepatozoon spp. and Leishmania infantum in alpine wild canids and mustelids from Italy. For this study, spleen samples of 157 foxes (Vulpes vulpes), 45 badgers (Meles meles), and 33 wolves (Canis lupus) collected between 2009 and 2017 in Northwest Italy were examined by using conventional PCR. Logistic regression was used to identify possible risk factors for pathogen infections. DNA of any of the tested pathogens was found in more than 90% of the analyzed animals. In particular, Babesia spp. showed significantly higher prevalence in foxes (89.7%) and badgers (89.6%) than in wolves, while the latter were considerably more infected with Hepatozoon canis (75.8%) than foxes (5.1%). None of the badger tested positive for Hepatozoon spp., although they showed high prevalence of Leishmania infantum (53.3%). Sequencing results revealed the presence, among others, of Babesia vulpes, Babesia sp. isolate badger type A and B, and Anaplasma phagocytophilum. Moreover, previously unreported pathogen/host associations were observed, such as Babesia capreoli in wolves and badgers. The prevalence of vector-borne pathogens observed in the present study is one of the highest reported so far, suggesting the importance of free-ranging carnivorans in the epidemiology and maintenance of the sylvatic cycle of the pathogens. Moreover, several of these pathogens are of particular importance regarding human (A. phagocytophilum, L. infantum) and pet health (L. infantum, B. vulpes).

Epidemiological evaluation of Leishmania infantum zoonotic transmission risk in the recently established endemic area of Northwestern Italy

Leishmania infantum infection had been expanding into new areas due to changes in vector and host biology. Zoonotic visceral leishmaniasis has become endemic in previously unsuitable areas as vectors find favourable climatic conditions and an increasing number of reservoir dogs are moved between traditionally and new endemic areas. Monitoring vector and disease expansion in areas of recent colonization is needed to understand transmission mechanisms and patterns of disease establishment. Here, we studied the infection status of 815 human blood donors and of 803 sympatric dogs from five, newly endemic, areas in Northwestern Italy. In autochthonous dogs, the seroprevalence of anti-L. infantum antibodies, recorded by Western blot, reached 42.22%, while in humans, the seroprevalence was of 16.81%. No significant correlation between the infection status of dogs and that of their human owners was found, but L. infantum infection was recorded in the different study areas with significant levels of diversity. Restriction fragment length polymorphism showed a high genetic variability of the circulating strains and gave useful insights on patterns of disease establishment into a naïve area.

Isolation and molecular characterization of Leishmania infantum in urine from patients with visceral leishmaniasis in Brazil

Leishmania infantum is a protozoan that causes visceral leishmaniasis, a potentially deadly neglected tropical disease. The gold standard for diagnosis has traditionally been detection of amastigotes in bone marrow or spleen aspirates, but this is an invasive procedure that carries the risk of serious complications. Newer PCR techniques are opening new avenues and tissues for testing. Therefore, we tested if amastigotes and DNA from L. infantum could be detected in patient urine. We detected L. infantum DNA in six out of 30 urine samples from patients with visceral leishmaniasis and the promastigotes were isolated in culture from the urine of one patient. These results suggest the feasibility of using urine samples to diagnose visceral leishmaniasis, especially in acute cases or renal infection, providing a valuable tool for doctors and clinicians to use for screening and diagnosis of leishmaniasis in patients.

Distinct Leishmania infantum Strains Circulate in Humans and Dogs in the Emilia-Romagna Region, Northeastern Italy

Human leishmaniasis is an emerging problem in Italy and is on the increase in the Emilia-Romagna region, northeastern part of the country. Nevertheless, studies dealing with the molecular characterization of Leishmania spp. circulating in these areas are limited. In the present work, we explored the genetic polymorphism of Leishmania isolates from 28 cases of canine leishmaniasis and three cases of human visceral leishmaniasis (VL), which occurred in 2013-2014 in the Emilia-Romagna region. The characterization was carried out in comparison with nine human isolates of Leishmania from other VL endemic Italian regions and two reference strains. Nucleic acid from 31 Leishmania-positive phlebotomine sandfly pools, sampled in 2012-2013 in the Emilia-Romagna region, were also evaluated. DNA amplification and sequencing of the ribosomal internal transcribed spacer-1 and of a repetitive nuclear region on chromosome 31 were carried out for genotyping. Two size polymorphic targets were also analyzed by PCR, the cpb E/F-gene and the k26-gene. Altogether, the analysis showed the circulation of different Leishmania infantum genotypes in the Emilia-Romagna region: two genotypes found in dogs from public kennels were similar to VL isolates from other Italian regions, whereas a third genotype was detected in VL cases of the Emilia-Romagna region and in all but one of the sandfly pools. The combined molecular tools applied in this study can constitute a helpful support for parasite tracking (e.g., in outbreak investigations) and for a better understanding of the epidemiological evolution of leishmaniasis in northeastern Italy.

Detection of Leishmania DNA in wild foxes and associated ticks in Patagonia, Argentina, 2000 km south of its known distribution area

BACKGROUND

Zoonotic Visceral Leishmaniasis (ZVL) is a vector-borne disease affecting humans and other mammals and caused by the protozoan parasite Leishmania (Leishmania) infantum (syn. L. chagasi), belonging to the L. donovani complex. The regions in Northern Argentina (above 32 °S) are its southern distribution limit in South America.

RESULTS

We detected Leishmania sp. DNA (most likely belonging to the L. donovani complex) in 37.5% of 32 grey foxes (Pseudalopex griseus) captured in Argentinean Patagonia (48°S and 50°S). Eleven monosexual pools of Amblyomma tigrinum ticks from eight different foxes (six grey foxes and two culpeo foxes P. culpaeus) were also positive. The southernmost known distribution limit for L. infantum, and the southernmost reported capture of a phlebotominae, had previously been 2000 and 750 km north of our study area, respectively.

CONCLUSIONS

This finding is significant because it markedly extends the distribution area of leishmaniasis; supports the existence of a sylvatic cycle in the absence of dogs; and has implications in transmission, indicating that either sand fly distribution is broader than currently thought or non-sand fly Leishmania maintenance is possible. Additional molecular, parasitological, epidemiological and entomological studies are still needed.

Molecular identification of Leishmania isolates obtained from patients suspected as having cutaneous leishmaniasis referred to reference laboratories from Yazd province in central Iran

Background:

Cutaneous leishmaniasis (CL) continues to be an increasing public health problem in Iran. The dominant etiologic agents of CL in the Old World are Leishmania major and Leishmania tropica. One of the important endemic foci of CL in Iran is Yazd. Recently, previous studies showed the equal prevalence of L. major and L. tropica as the agents of cutaneous leishmaniasis in this area. This prompted us to identify the genotype of L. major isolates obtained from patients with cutaneous leishmaniasis.

Materials and Methods:

After completing a clinical/epidemiologic data questionnaire for 218 patients with suspected skin lesions, scraping samples were collected, and each specimen was examined using both direct microscopy and molecular assay of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

Results:

Results showed that of the 218 samples, Leishman body was observed in 77 by direct smear and 104 by PCR assay. Molecular assay indicated 50 cases as L. major, 52 cases as L. tropica, and two cases as unknown. Molecular characterization of L. major isolates showed four patterns, named LmA1, LmA2, LmA3, and LmA4.

Conclusion:

Our study is the first report for molecular characterization of L. major from one of the important central province of Iran that could affect the control strategies in this field.

Epidemiology of Leishmania infantum, Toxoplasma gondii, and Neospora caninum in Rattus rattus in absence of domestic reservoir and definitive hosts

Isolated environments are privileged settings to study transmission of infection. Montecristo is a small island where no wild or domestic carnivores are present. Invasive Black rats Rattus rattus (n=78) were captured and tested by PCR for Leishmania infantum, Toxoplasma gondii and Neospora caninum. We wanted to test, for these parasites, the existence of a sylvatic cycle independent of reservoir or definitive hosts. None of the rats tested positive by PCR for either T. gondii or N. caninum. We recorded a 15.5% prevalence (CI95% 8-26%) of L. infantum in the rats and Phlebotomus mascittii was captured in Montecristo, leading us to identify it as possible vector of the parasite.

Leishmania infantum in free-ranging hares, Spain, 2004-2010

Iberian hares (Lepus granatensis) were recently deemed responsible for an outbreak of human leishmaniasis affecting metropolitan Madrid, Spain. However, the reservoir potential of hares in Europe is poorly known. We report a retrospective survey on Leishmania infantum, the causal agent of zoonotic endemic leishmaniasis in the Mediterranean basin, infection status of Iberian, European (Le. europaeus) and Broom (Le. castroviejoi) hares in Spain. Spleen samples from 94 hares were tested by polymerase chain reaction. Sequencing and restriction fragment length polymorphism (RFLP) assays were performed on positive samples and RFLP patterns compared with those of strains reported in the scientific literature. DNA prevalence in hare spleen samples was 43.6% (95% confidence interval: 33.6-53.6). In all six regions studied at least one positive sample was found. RFLP revealed existence of specific hare strains of L. infantum differing from those reported in wild carnivores in Spain. The widespread presence of L. infantum in the most abundant Spanish hare species and the recent evidence of the ability of naturally infected hares to transmit the pathogen to Phlebotomus perniciosus, its main vector in the western Mediterranean, suggest that hares may have an unexpected role in the epidemiology of L. infantum in Spain.

Ixodid fauna and zoonotic agents in ticks from dogs: first report of Rickettsia rickettsii in Rhipicephalus sanguineus in the state of Mato Grosso do Sul, mid-western Brazil

Ticks from 148 dogs from the urban area of the municipality of Campo Grande, state of Mato Grosso do Sul, Brazil, were collected, classified and analyzed using polymerase chain reaction (PCR) for the identification of Rickettsia spp., Trypanosoma cruzi and Leishmania spp. A total of 2015 ticks were collected. The species Rhipicephalus sanguineus (98.9 %) and Amblyomma cajennense (1.1 %) were identified. Molecular analysis revealed that no tick samples were infected by T. cruzi. Regarding Leishmania spp., tick samples from 36 dogs spread across all regions of the municipality were positive for L. chagasi. One tick sample was positive for Rickettsia spp. (gltA gene) in the PCR reaction. This sample was submitted to further PCR based on the ompA gene and the amplicon was sequenced. Identity of 100 % was found with homologous sequences of R. rickettsii available in GenBank. This paper is the first to report the natural infection of R. sanguineus by R. rickettsii in the municipality of Campo Grande, state of Mato Grosso do Sul, mid-western Brazil.

Evaluation of a rapid device for serological diagnosis of Leishmania infantum infection in dogs as an alternative to immunofluorescence assay and Western blotting

In this study, we compared a rapid immunochromatographic test (Speed Leish K; BVT Groupe Virbac, La Seyne sur Mer, France) with an indirect immunofluorescence assay (IFAT) and Western blotting (WB) for the detection of Leishmania infantum antibodies in dogs. A total of 250 serum samples were collected from 125 L. infantum-positive and 125 L. infantum-negative dogs. Among the positive samples, 81 were strongly positive at low IFAT dilutions, while 44 were low-reactivity sera (IFAT titers, 1:40 to 1:80). The sensitivity and specificity of the Speed Leish K were 96.3% and 100%, respectively, compared with those of the IFAT. When IFAT low-reactivity sera (titers, 1:40 or 1:80) were tested with the Speed Leish K, using WB results as a reference, the sensitivities were 93.75% for sera with a 1:80 titer and 73.33% for sera with a 1:40 titer, and the specificity was 100%. The Speed Leish K is easy to use and performs well, so it can be considered a quick and reliable tool for the diagnosis of L. infantum infection in dogs.

KDNA genetic signatures obtained by LSSP-PCR analysis of Leishmania (Leishmania) infantum isolated from the new and the old world

BACKGROUND

Visceral Leishmaniasis (VL) caused by species from the Leishmania donovani complex is the most severe form of the disease, lethal if untreated. VL caused by Leishmania infantum is a zoonosis with an increasing number of human cases and millions of dogs infected in the Old and the New World. In this study, L. infantum (syn. L.chagasi) strains were isolated from human and canine VL cases. The strains were obtained from endemic areas from Brazil and Portugal and their genetic polymorphism was ascertained using the LSSP-PCR (Low-Stringency Single Specific Primer PCR) technique for analyzing the kinetoplastid DNA (kDNA) minicircles hypervariable region.

PRINCIPAL FINDINGS

KDNA genetic signatures obtained by minicircle LSSP-PCR analysis of forty L. infantum strains allowed the grouping of strains in several clades. Furthermore, LSSP-PCR profiles of L. infantum subpopulations were closely related to the host origin (human or canine). To our knowledge this is the first study which used this technique to compare genetic polymorphisms among strains of L. infantum originated from both the Old and the New World.

CONCLUSIONS

LSSP-PCR profiles obtained by analysis of L. infantum kDNA hypervariable region of parasites isolated from human cases and infected dogs from Brazil and Portugal exhibited a genetic correlation among isolates originated from the same reservoir, human or canine. However, no association has been detected among the kDNA signatures and the geographical origin of L. infantum strains.

Presence of amastigotes in the central nervous system of hamsters infected with Leishmania sp

Visceral leishmaniasis (VL) is a severe chronic disease caused by Leishmania (Leishmania) infantum chagasi. Better knowledge on the effects caused by this disease can help develop adequate clinical management and treatment. Parasitological and immunohistochemical studies were performed golden hamsters Mesocricetus auratus infected with bone marrow from individuals with VL in the State of Mato Grosso do Sul, central-west Brazil. The effects of parasitism in the spleen, liver, kidneys, lungs, heart and brain of the animals were examined. Eighteen hamsters were inoculated intraperitoneally, and six healthy animals were used as negative controls. The animals were kept in the animal house and checked for clinical signs. Specimens of each organ were examined for the presence of amastigotes. Immunohistochemical technique was performed in all brain specimens and organs negative on the direct examination of parasites. Direct examination of amastigotes was positive in the spleen and liver of all infected animals; 33.3% showed the parasite in the kidneys and lungs, and 16.7% in the heart. Parasitic forms were seen in 83.3% (15/18) of the brain examined. Immunohistochemistry confirmed the results of the direct examination, except in two specimens of lung tissue and in the brain specimens. Other studies are needed to further clarify the effect of the parasite in the central nervous system.

An investigation into alternative reservoirs of canine leishmaniasis on the endemic island of Mallorca (Spain)

The role of wild and free-roaming domestic carnivores as a reservoir of Leishmania infantum was investigated on the Mediterranean island of Mallorca (Balearic Islands, Spain), an endemic area for this disease. Serum, blood and/or spleen samples from 169 animals [48 dogs from a kennel, 86 wild-caught feral cats, 23 pine martens (Martes martes), 10 common genets (Genetta genetta) and two weasels (Mustela nivalis)] were analysed. Seroprevalence determined by Western blotting was 38% in dogs and 16% in feral cats, while the prevalence of infection determined by PCR was 44% in dogs, 26% in cats, 39% in pine martens and 10% in genets. This is the first report of infection by L. infantum in the pine marten or any other member of the Mustelidae family. Restriction fragment length polymorphism (RFLP) analysis found 33 different patterns in 23 dogs, 14 cats and three martens. Two patterns were shared by dogs and cats, two by different cats, and one by different dogs. Patterns were different to those previously reported in carnivores from peninsular Spain. No external lesions compatible with leishmaniasis were observed in any species other than the dogs. Although the dog is probably the primary reservoir of leishmaniasis in endemic areas, the prevalence and the absence of apparent signs of this disease within the island's abundant feral cat and pine marten populations could make these species potential primary or secondary hosts of L. infantum in Mallorca.

Distribution of Phlebotomus perniciosus in North-Italy: a study on 18S rDNA of phlebotomine sand flies

Leishmaniasis has recently spread, and is now endemic, in many parts of North Italy, even if it is not clear how sand flies vectors have reached this area. In order to clarify the origin of the Phlebotomus perniciosus, the main sand flies specie found in these areas, we analyzed and compared the 18S rDNA sequence from 33 out of 122 P. perniciosus collected in new endemic areas, from neighbor (<or=120 km) traditionally endemic area (Liguria) and from an area about 400 km far from the North West Italy. Based on the 18S rDNA sequence analysis, three different groups with different degrees of heterogeneity were identified. Two of them are suggestive of migration at a local scale and one, found in all sampled foci, is probably due to passive carriage. Results suggest that both migration on small scale from traditionally endemic area and passive carriage on long distance can contribute to sand flies colonization of new areas.

[Identification of Leishmania species isolated in human cases in Mato Grosso do Sul, by means of the polymerase chain reaction]

Leishmaniases are endemic zoonoses in the State of Mato Grosso do Sul. Their etiological agents in this region of Brazil are Leishmania (Leishmania) chagasi, Leishmania (Leishmania) amazonensis and Leishmania (Viannia) braziliensis. The polymerase chain reaction (PCR) is a tool with high specificity and sensitivity for identifying Leishmania species. This study examined 39 cryopreserved isolates of Leishmania that had been collected by bone marrow aspiration and/or lesion biopsy, depending on the clinical suspicion. The isolates were subjected to DNA extraction and PCR using the following primers: RV1/RV2 for identifying Leishmania (Leishmania) chagasi, a1/a2 for Leishmania (Leishmania) amazonensis and b1/b2 for Leishmania (Viannia) braziliensis.Leishmania (Leishmania) chagasi was the only species identified in the 37 cases of visceral leishmaniasis.Leishmania (Leishmania) amazonensis was identified in two isolates from patients with a diagnosis of cutaneous leishmaniasis. The results obtained confirm that it is possible to use these three pairs of primers as a tool for characterizing Leishmania isolates.

Asymptomatic Leishmania infantum infection in an area of northwestern Italy (Piedmont region) where such infections are traditionally nonendemic

The prevalence of Leishmania infantum-specific antibodies and asymptomatic infection was assessed in a randomized sample of 526 healthy adults from a continental area of northwestern Italy where L. infantum is not endemic and where autochthonous cases of visceral leishmaniasis (VL) were recently reported. L. infantum-specific antibodies were detected by Western blotting (WB) in 39 subjects (7.41%), while L. infantum kinetoplast DNA was amplified from buffy coat in 21 out of 39 WB-positive subjects, confirming asymptomatic infection in 53.8% of seropositives. Risk factors significantly associated with WB positivity were uninterrupted residence since childhood in a local rural environment (odds ratio [OR], 3.5; 95% confidence interval [CI], 1.7 to 7.3), daily contact with animals though not exclusively with dogs (OR, 3.7; 95% CI, 1.3 to 10.7), older age (OR, 2.31; 95% CI, 1.2 to 4.5), and agricultural/other outdoor activities (OR, 3.8; 95% CI, 0.99 to 3.7.) Logistic regression analysis showed that uninterrupted residence in a local rural environment and an age of >65 years were the only independent predictors of seropositivity assessed by WB. Follow-up at 24 months did not show evidence of VL in either seropositive or PCR-positive subjects. The detection of a high seroprevalence rate, confirmed as asymptomatic infection by PCR in more than half of the cases, among healthy residents in a continental area of northwestern Italy makes local L. infantum transmission very likely. In a region where VL is considered nonendemic, these findings warrant further epidemiological investigations as well as interventions with respect to both the canine reservoir and vectors, given the possible risks for immunosuppressed patients.

Molecular diagnosis of canine visceral leishmaniasis: identification of Leishmania species by PCR-RFLP and quantification of parasite DNA by real-time PCR

The efficacies of polymerase chain reaction (PCR) procedures for the diagnosis of canine visceral leishmaniasis (CVL), and of PCR-restriction fragment length polymorphism (RFLP) analysis for the identification of Leishmania species, have been assessed. Quantitative real-time PCR employing a SYBR Green dye-based system was standardised for the quantification of Leishmania kDNA minicircles. Skin, peripheral blood and bone marrow samples collected from 217 dogs, asymptomatic or symptomatic for CVL, were analysed. The PCR method, which was based on the amplification of a 120 bp kDNA fragment conserved across Leishmania species, was able to detect the presence in clinical samples of protozoan parasite DNA in amounts as low as 0.1 fg. Bone marrow and skin samples proved to be more suitable than peripheral blood for the detection of Leishmania by PCR and presented positive indices of 84.9% and 80.2%, respectively. PCR-RFLP analysis indicated that 192 of the PCR-positive dogs were infected with Leishmania infantum chagasi, whilst L. braziliensis was identified in two other animals. Quantitative PCR revealed that bone marrow samples from dogs presenting positive conventional tests contained a higher number of copies of Leishmania kDNA than peripheral blood, although no significant differences were detected between symptomatic and asymptomatic dogs in terms of parasite load. This study demonstrates that PCR can be used for the detection of Leishmania in clinical samples derived from naturally infected dogs, and that PCR-RFLP represents a rapid and sensitive tool for the identification of Leishmania species. Additionally, qPCR is effective in quantifying Leishmania DNA load in clinical samples.

Kinetoplast DNA heterogeneity among Leishmania infantum strains in central Israel and Palestine

Leishmania infantum is the causative agent of canine and human visceral leishmaniasis in Israel and Palestine. Amplification of the kinetoplast DNA (kDNA), followed by restriction fragment length polymorphism (RFLP) analysis with restriction enzymes was used to examine the genotypic association between L. infantum strains isolated from 22 dogs and 2 humans from these adjoining regions. Results showed wide kDNA heterogeneity in these strains. Two main clusters (A and B) were identified. Cluster A was restricted to central Israel and was mainly found in strains isolated after 2002 whereas cluster B included parasites from central Israel and the West Bank. The kDNA microheterogeneity in L. infantum parasite populations as shown by genotyping with the kDNA-PCR and RFLP provided a tool to study the epidemiology of the disease and track its spread in central Israel and Palestine.

Detection and species identification of Old World Leishmania in clinical samples using a PCR-based method

The aim of this study was to develop a simple, low-cost method for the detection and species differentiation of Leishmania directly from clinical samples, for routine use in a parasitology laboratory. A total of 87 samples was used, including 60 peripheral blood, seven bone marrow and 17 skin lesion material samples, derived from Greek patients with visceral or cutaneous leishmaniasis, and three reference strains. PCR was performed using primers designed to amplify the internal transcribed spacer 1 (ITS1) region of the rRNA gene. Identification of the Leishmania species studied was achieved by digestion with a single restriction endonuclease (RFLP), single-strand conformational polymorphism (SSCP) and DNA sequencing of the PCR-generated fragments. Typing identified all visceral and one cutaneous leishmaniasis strains as L. infantum, twelve of the cutaneous leishmaniasis strains as L. tropica and four as L. major. The described PCR method proved efficient for the detection of pathogenic Leishmania species in various clinical samples, most importantly in peripheral blood samples. Furthermore, PCR followed by a simple RFLP using a single restriction endonuclease was capable of identifying all Leishmania species commonly encountered in Greece.

Membranoproliferative glomerulonephritis type III in a simultaneous infection of Leishmania infantum and Dirofilaria immitis in a dog

In this report a 9-year-old female German Shepherd dog with a membranoproliferative glomerulonephritis (MPGN) type III associated with concomitant infection of Dirofilaria immitis and Leishmania infantum is presented. Light microscopic evaluation of kidney revealed a diffuse hypercellularity and thickening of glomerular basement membrane. Heavy and coarse granular complement C(3) deposition and a weaker positive reaction to immunoglobulin G were present along peripheral glomerular basement membrane and in the mesangium in the immunofluorescent study. Transmission electron microscopy revealed deposits in the mesangium, subendothelium, and subepithelium. These lesions are compatible with membranoproliferative glomerulonephritis type III in humans.

Leishmania and the leishmaniases: a parasite genetic update and advances in taxonomy, epidemiology and pathogenicity in humans

Leishmaniases remain a major public health problem today despite the vast amount of research conducted on Leishmania pathogens. The biological model is genetically and ecologically complex. This paper explores the advances in Leishmania genetics and reviews population structure, taxonomy, epidemiology and pathogenicity. Current knowledge of Leishmania genetics is placed in the context of natural populations. Various studies have described a clonal structure for Leishmania but recombination, pseudo-recombination and other genetic processes have also been reported. The impact of these different models on epidemiology and the medical aspects of leishmaniases is considered from an evolutionary point of view. The role of these parasites in the expression of pathogenicity in humans is also explored. It is important to ascertain whether genetic variability of the parasites is related to the different clinical expressions of leishmaniasis. The review aims to put current knowledge of Leishmania and the leishmaniases in perspective and to underline priority questions which 'leishmaniacs' must answer in various domains: epidemiology, population genetics, taxonomy and pathogenicity. It concludes by presenting a number of feasible ways of responding to these questions.