Showing papers on "Visceral leishmaniasis published in 2009"
TL;DR: A review of the transmission and control of ZVL can be found in this article, which highlights the lack of randomized controlled trials of both dog culling and residual insecticide spraying.
Abstract: Zoonotic visceral leishmaniasis (ZVL) caused by Leishmania infantum is an important disease of humans and dogs. Here we review aspects of the transmission and control of ZVL. Whilst there is clear evidence that ZVL is maintained by sandfly transmission, transmission may also occur by non-sandfly routes, such as congenital and sexual transmission. Dogs are the only confirmed primary reservoir of infection. Meta-analysis of dog studies confirms that infectiousness is higher in symptomatic infection; infectiousness is also higher in European than South American studies. A high prevalence of infection has been reported from an increasing number of domestic and wild mammals; updated host ranges are provided. The crab-eating fox Cerdocyon thous, opossums Didelphis spp., domestic cat Felis cattus, black rat Rattus rattus and humans can infect sandflies, but confirmation of these hosts as primary or secondary reservoirs requires further xenodiagnosis studies at the population level. Thus the putative sylvatic reservoir(s) of ZVL remains unknown. Review of intervention studies examining the effectiveness of current control methods highlights the lack of randomized controlled trials of both dog culling and residual insecticide spraying. Topical insecticides (deltamethrin-impregnated collars and pour-ons) have been shown to provide a high level of individual protection to treated dogs, but further community-level studies are needed.
402 citations
TL;DR: Treatment of cutaneous and mucocutaneous leishmaniasis depends on the species of Leishmania and the risk of widespread or disfiguring disease.
Abstract: Leishmaniasis is a cluster of diseases caused by protozoa in the genus Leishmania. There are three basic clinical forms: cutaneous, mucocutaneous, and visceral leishmaniasis. The present review focuses on the diagnosis and treatment of cutaneous and mucocutaneous leishmaniasis. Characteristics of both the human host and the parasite species influence the clinical disease manifestations that range from asymptomatic exposure, to self-healing skin ulcers, to life-threatening widespread destructive ulcerations. Whether through medical treatment or through spontaneous resolution, skin ulcerations generally result in disfiguring scars with significant social and economic impact. Tests to confirm the diagnosis should be performed on patients who have recently visited endemic areas and have skin or mucosal manifestations consistent with leishmaniasis. Treatment depends on the species of Leishmania and the risk of widespread or disfiguring disease. Because of increasing trends in global travel, educating health care providers to recognize and treat leishmaniasis in both endemic and non-endemic countries is imperative.
259 citations
TL;DR: The main results demonstrated that lower frequency of circulating B cells and monocytes are important markers of severe CVL, whereas increased levels of CD8+ lymphocytes appear to be the major phenotypic feature of asymptomatic disease.
191 citations
TL;DR: Transmission of cutaneous leishmaniasis (CL) caused by Leishmania infantum was studied in South Anatolia, Turkey and it is suggested that the transmission cycle could be anthroponotic.
151 citations
TL;DR: Results indicate that LdCen1−/− can be a safe and effective vaccine candidate against VL as well as mucocutaneous leishmaniasis causing parasites.
Abstract: No vaccine is currently available for visceral leishmaniasis (VL) caused by Leishmania donovani. This study addresses whether a live attenuated centrin gene-deleted L. donovani (LdCen1(-/-)) parasite can persist and be both safe and protective in animals. LdCen1(-/-) has a defect in amastigote replication both in vitro and ex vivo in human macrophages. Safety was shown by the lack of parasites in spleen and liver in susceptible BALB/c mice, immune compromised SCID mice, and human VL model hamsters 10 wk after infection. Mice immunized with LdCen1(-/-) showed early clearance of virulent parasite challenge not seen in mice immunized with heat killed parasites. Upon virulent challenge, the immunized mice displayed in the CD4(+) T cell population a significant increase of single and multiple cytokine (IFN-gamma, IL-2, and TNF) producing cells and IFN-gamma/IL10 ratio. Immunized mice also showed increased IgG2a immunoglobulins and NO production in macrophages. These features indicated a protective Th1-type immune response. The Th1 response correlated with a significantly reduced parasite burden in the spleen and no parasites in the liver compared with naive mice 10 wk post challenge. Protection was observed, when challenged even after 16 wk post immunization, signifying a sustained immunity. Protection by immunization with attenuated parasites was also seen in hamsters. Immunization with LdCen1(-/-) also cross-protected mice against infection with L. braziliensis that causes mucocutaneous leishmaniasis. Results indicate that LdCen1(-/-) can be a safe and effective vaccine candidate against VL as well as mucocutaneous leishmaniasis causing parasites.
150 citations
TL;DR: This review focuses the dichotomy of immune response against various clinical forms of the disease, and an in-depth knowledge of sequences involved in the immune response to the parasite would help in designing prophylactic and therapeutic strategies against leishmaniasis.
Abstract: Leishmaniasis is a parasitic disease caused by various species of Leishmania, a unicellular kinetoplastid protozoan flagellate. It manifests mainly in 3 clinical forms; visceral leishmaniasis (VL), cutaneous leishmaniasis (CL) and mucocutaneous leishmaniasis (MCL), of which VL is the most severe form of the disease. VL is lethal if untreated and spontaneous cure is extremely rare. Cutaneous leishmaniasis usually has milder course and often results into a self-healing of ulcers. Resolution of leishmanial infection is dependent on the coordinated interactions between components of cell mediated immune response, specifically the activation of targeted T-cell populations for appropriate cytokine production and activation of macrophages. In murine model, the development of Th1 response is associated with control of infection, and Th2 response is associated with disease progression. However, Thl and Th2 dichotomy in the human system is not as distinct as in mice and the murine model does not strictly apply to human leishmaniasis. This review focuses the dichotomy of immune response against various clinical forms of the disease. An in-depth knowledge of sequences involved in the immune response to the parasite would help in designing prophylactic and therapeutic strategies against leishmaniasis.
150 citations
TL;DR: Certain sand fly salivary proteins are potent immunogens obligatorily co-deposited with Leishmania parasites during transmission and their inclusion in an anti-Leishmania vaccine would exploit anti-saliva immunity following an infective sand fly bite and set the stage for a protective anti- leishmania immune response.
Abstract: Immunity to a sand fly salivary protein protects against visceral leishmaniasis (VL) in hamsters. This protection was associated with the development of cellular immunity in the form of a delayed-type hypersensitivity response and the presence of IFN-γ at the site of sand fly bites. To date, there are no data available regarding the cellular immune response to sand fly saliva in dogs, the main reservoirs of VL in Latin America, and its role in protection from this fatal disease. Two of 35 salivary proteins from the vector sand fly Lutzomyia longipalpis, identified using a novel approach termed reverse antigen screening, elicited strong cellular immunity in dogs. Immunization with either molecule induced high IgG2 antibody levels and significant IFN-γ production following in vitro stimulation of PBMC with salivary gland homogenate (SGH). Upon challenge with uninfected or infected flies, immunized dogs developed a cellular response at the bite site characterized by lymphocytic infiltration and IFN-γ and IL-12 expression. Additionally, SGH-stimulated lymphocytes from immunized dogs efficiently killed Leishmania infantum chagasi within autologous macrophages. Certain sand fly salivary proteins are potent immunogens obligatorily co-deposited with Leishmania parasites during transmission. Their inclusion in an anti-Leishmania vaccine would exploit anti-saliva immunity following an infective sand fly bite and set the stage for a protective anti-Leishmania immune response.
140 citations
TL;DR: PCR analysis of serially collected ejaculates indicated that shedding of Leishmania in the semen is intermittent, supporting the notion that L. chagasi may be sexually transmitted from naturally infected dogs to susceptible bitches in the absence of the biological insect vector.
128 citations
TL;DR: The balance of expression of IFN-gamma and TNF-alpha (protective) and IL-10 and TGF-beta (disease progression) in lymph nodes determine parasite burden and clinical expression in naturally infected dogs.
120 citations
TL;DR: Recent advances in the identification of genetic loci involved in the host response to Leishmania spp.
113 citations
TL;DR: 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 Leishesmania species.
TL;DR: An assay to measure amphotericin B susceptibility was developed and found no evidence of decreased susceptibility among strains isolated from patients, some of whom were infected with the same isolate for up to 10 years.
Abstract: BACKGROUND Visceral leishmaniasis (VL) is an opportunistic infection that can occur among patients infected with human immunodeficiency virus type 1 (HIV-1) in areas where both infections are endemic. Highly active antiretroviral therapy has decreased the incidence of VL in southern Europe among HIV-1-infected patients, but VL is still observed among patients with low CD4 cell counts, and most coinfected patients receiving highly active antiretroviral therapy experienced relapse, despite initial treatment with liposomal amphotericin B. METHODS Through long-term monitoring of VL in 10 patients with HIV-1 infection and/or AIDS, we compared parasite strains derived from primary and secondary episodes of VL. All the patients have received many courses of amphotericin B treatment and/or prophylaxis. RESULTS Through molecular techniques, we have shown that secondary episodes of VL can be attributable to relapse (7 of 10 episodes) or reinfection (3 of 10). We developed an assay to measure amphotericin B susceptibility and found no evidence of decreased susceptibility among strains isolated from patients, some of whom were infected with the same isolate for up to 10 years. CONCLUSIONS This apparent absence of resistance, as determined by in vitro susceptibility testing, has important consequences and suggests that amphotericin B will remain a useful drug of choice against VL, even after repetitive treatments or prophylactic use.
TL;DR: Analysis of large DNA banks from India and Brazil makes it possible to undertake genome‐wide association studies (GWAS), which are ongoing as part of phase 2 of the Wellcome Trust Case Control Consortium, and should seed research into novel genes and mechanisms that influence susceptibility to VL.
Abstract: Ninety percent of the 500,000 annual new cases of visceral leishmaniasis occur in India/Bangladesh/Nepal, Sudan and Brazil. Importantly, 80-90% of human infections are sub-clinical or asymptomatic, usually associated with strong cell-mediated immunity. Understanding the environmental and genetic risk factors that determine why two people with the same exposure to infection differ in susceptibility could provide important leads for improved therapies. Recent research using candidate gene association analysis and genome-wide linkage studies (GWLS) in collections of families from Sudan, Brazil and India have identified a number of genes/regions related both to environmental risk factors (e.g. iron), as well as genes that determine type 1 versus type 2 cellular immune responses. However, until now all of the allelic association studies carried out have been underpowered to find genes of small effect sizes (odds ratios or OR<2), and GWLS using multicase pedigrees have only been powered to find single major genes, or at best oligogenic control. The accumulation of large DNA banks from India and Brazil now makes it possible to undertake genome-wide asscociation studies (GWAS), which are ongoing as part of phase two of the Wellcome Trust Case Control Consortium. Data from this analysis should seed research into novel genes and mechanisms that influence susceptibility to visceral leishmaniasis.
TL;DR: An analysis of sequential data from studies of visceral leishmaniasis in hamsters suggests that factors outside of the immune system are responsible for the early inactivation of inducible nitric oxide synthase, which occurs before the expression of deactivating cytokines.
Abstract: Visceral leishmaniasis is caused by protozoan parasites of the Leishmania donovani complex. During active disease in humans, high levels of IFN-γ and TNF-α detected in blood serum, and high expression of IFN-γ mRNA in samples of the lymphoid organs suggest that the immune system is highly activated. However, studies using peripheral blood mononuclear cells have found immunosuppression specific to Leishmania antigens; this poor immune response probably results from Leishmania antigen-engaged lymphocytes being trapped in the lymphoid organs. To allow the parasites to multiply, deactivating cytokines IL-10 and TGF-β may be acting on macrophages as well as anti-Leishmania antibodies that opsonize amastigotes and induce IL-10 production in macrophages. These high activation and deactivation processes are likely to occur mainly in the spleen and liver and can be confirmed through the examination of organ samples. However, an analysis of sequential data from studies of visceral leishmaniasis in hamsters suggests that factors outside of the immune system are responsible for the early inactivation of inducible nitric oxide synthase, which occurs before the expression of deactivating cytokines. In active visceral leishmaniasis, the immune system actively participates in non-lymphoid organ lesioning. While current views only consider immunocomplex deposition, macrophages, T cells, cytokines, and immunoglobulins by diverse mechanism also play important roles in the pathogenesis.
TL;DR: Despite the lower sensitivity in a population with a high prevalence of HIV, the DiaMed-IT-Leish rK39 test enables decentralization of diagnosis and should undergo follow-up DAT testing, especially if they are HIV positive.
Abstract: Accuracy of an rK39 rapid diagnostic test (DiaMed-IT-Leish ® ) for visceral leishmaniasis (VL) was com- pared with splenic aspiration and the direct agglutination test (DAT) in a population with a high prevalence of infection with human immunodeficiency virus (HIV) in Ethiopia. There were 699 patients clinically suspected of having VL (153 parasitologically confirmed, 482 DAT confirmed, and 130 DAT negative), and 97 DAT-negative controls. A total of 84% were tested for HIV and 34% were HIV positive. Sensitivity of the rK39 test in parasitologically confirmed VL patients was 84% (77% in HIV positive and 87% in HIV negative; P = 0.25). Sensitivity of the DAT was higher (94%; P = 0.01), 89% in HIV-positive patients and 95% in HIV-negative patients; P = 0.27). Specificity of the rK39 test was 99% in DAT- negative controls and 92% in DAT-negative patients clinically suspected of having VL. A diagnostic algorithm combin- ing DAT and the rK39 test had a sensitivity of 98% in HIV-positive VL patients and 99% in HIV-negative VL patients. Despite the lower sensitivity in a population with a high prevalence of HIV, the DiaMed-IT-Leish ® rK39 test enables decentralization of diagnosis. Patients clinically suspected of having VL who show negative results on the rK39 antigen test should undergo follow-up DAT testing, especially if they are HIV positive.
Journal Article•
TL;DR: Combination treatments are a cost-effective alternative to current monotherapy for VL given their expected impact on the emergence of drug resistance, and a switch to combination therapy should be considered once final results from clinical trials are available.
TL;DR: The results show that a single intraperitoneal administration of the A2-recombinant L. tarentolae strain protects BALB/c mice against L. infantum challenge and that protective immunity is associated with high levels of IFN-gamma production prior and after challenge.
TL;DR: Findings reveal a hitherto unknown IFN-β/SOD1 axis in Leishmania infection and suggest that inhibition of SOD-associated pathways could serve as strategy in the treatment of L. amazonensis as well as L. braziliensis infection, major human pathogens.
Abstract: Type I IFNs (IFN-alpha/beta) have only recently gained considerable attention as immunomodulators in nonviral infectious diseases. IFN-beta has been shown to protect, in a NO-dependent manner, against murine Old World leishmaniasis caused by Leishmania major, but data in New World leishmaniasis are lacking. We found that IFN-beta dose-dependently increases parasite burden in Leishmania amazonensis- as well as Leishmania braziliensis-infected human macrophages, independent of endogenous or exogenous NO. However, IFN-beta significantly reduced superoxide release in Leishmania-infected as well as uninfected human macrophages. This decrease in superoxide production was paralleled by a significant IFN-beta-mediated increase in superoxide dismutase 1 (SOD1) protein levels. Additionally, IFN-beta inhibition of leishmanicidal activity was mimicked by SOD1 and antagonized by either pharmacological or small interfering RNA-mediated inhibition of SOD1. Finally, pronounced SOD1 expression in situ was demonstrated in biopsies from New World cutaneous leishmaniasis patients. These findings reveal a hitherto unknown IFN-beta/SOD1 axis in Leishmania infection and suggest that inhibition of SOD-associated pathways could serve as strategy in the treatment of L. amazonensis as well as L. braziliensis infection, major human pathogens.
TL;DR: Asymptomatic infected dogs as well as symptomatic ones can harbor L. infantum in their blood and skins which are virulent and infectious for inoculated golden hamster.
TL;DR: This reformulation of amphotericin B for oral administration has resulted in a highly efficacious antileishmanial treatment that significantly reduces or eradicates liver parasitemia in a murine model of visceral leishmaniasis.
Abstract: Visceral leishmaniasis is a deadly parasitic disease caused by obligate intramacrophage protozoans of the Leishmania genus. The World Health Organization estimates the annual death toll to be 50,000, with 500,000 new cases each year. Without treatment, visceral leishmaniasis is inevitably fatal. For the last 70 years, the first line of defense has been pentavalent antimonials; however, increased resistance has brought amphotericin B to the forefront of treatment options. Unfortunately, the difficult route of drug administration, toxicity issues, and cost prevent amphotericin B from reaching the infected population, and mortality continues to rise. Our reformulation of amphotericin B for oral administration has resulted in a highly efficacious antileishmanial treatment that significantly reduces or eradicates liver parasitemia in a murine model of visceral leishmaniasis. This formulation has overcome amphotericin B's significant physicochemical barriers to absorption and holds promise for the development of a self-administered oral therapy for the treatment of visceral leishmaniasis.
TL;DR: The circulation of a single homogeneous population of L. donovani in Bihar (India), Bangladesh and Nepal is, most probably, related to the epidemic spread of visceral leishmaniasis in this area.
TL;DR: In multivariable analyses of 171 matched case-control pairs, dog ownership, sleeping under an acacia tree during the day, and habitually sleeping outside at night were associated with significantly increased risk of visceral leishmaniasis.
Abstract: We conducted a case-control study to evaluate risk factors for visceral leishmaniasis during an epidemic in a previously unaffected district of Ethiopia We also collected blood and bone marrow specimens from dogs in the outbreak villages In multivariable analyses of 171 matched case-control pairs, dog ownership, sleeping under an acacia tree during the day, and habitually sleeping outside at night were associated with significantly increased risk Specimens from 7 (38%) dogs were positive by immunofluorescent antibody test (IFAT) and both enzyme-linked immunosorbent assays (ELISAs), whereas Leishmania DNA was detected in 5 (28%) bone marrow aspirates (from 3 seropositive and 2 seronegative dogs) Insecticide-treated nets may only protect a portion of those at risk Further research on the vectors, the role of the dog in the transmission cycle, and the effect of candidate interventions are needed to design the best strategy for control
TL;DR: The results suggest the N-terminal domain of L. donovani ppg as a potential DNA vaccine against visceral leishmaniasis as well as golden hamsters against the L.Donovani challenge.
Abstract: Leishmania produce several types of mucin-like glycoproteins called proteophosphoglycans (PPGs) which exist as secretory as well as surface-bound forms in both promastigotes and amastigotes. The structure and function of PPGs have been reported to be species and stage specific as in the case of Leishmania major and Leishmania mexicana; there has been no such information available for Leishmania donovani. We have recently demonstrated that PPG is differentially expressed in sodium stibogluconate-sensitive and -resistant clinical isolates of L. donovani. To further elucidate the structure and function of the ppg gene of L. donovani, a partial sequence of its N-terminal domain of 1.6 kb containing the majority of antigenic determinants, was successfully cloned and expressed in prokaryotic as well as mammalian cells. We further evaluated the DNA-encoding N-terminal domain of the ppg gene as a vaccine in golden hamsters (Mesocricetus auratus) against the L. donovani challenge. The prophylactic efficacy to the tune of ∼80% was observed in vaccinated hamsters and all of them could survive beyond 6 mo after challenge. The efficacy was supported by a surge in inducible NO synthase, IFN-γ, TNF-α, and IL-12 mRNA levels along with extreme down-regulation of TGF-β, IL-4, and IL-10. A rise in the level of Leishmania-specific IgG2 was also observed which was indicative of enhanced cellular immune response. The results suggest the N-terminal domain of L. donovani ppg as a potential DNA vaccine against visceral leishmaniasis.
TL;DR: The first case of visceral leishmaniasis relapse in a healthy individual after complete miltefosine treatment and subsequent sequencing of the PCR-amplified product confirmed that this case was a L. donovani infection.
Abstract: We report the first case of visceral leishmaniasis (VL) relapse in a healthy individual after complete miltefosine treatment. The patient attended hospital with a history of fever for 2 months, splenomegaly, hepatomegaly, and weight loss. The case was confirmed as VL by microscopical detection of Leishmania parasites in a bone marrow specimen and by a positive result for the immunochromatography-based test targeting the Leishmania donovani rK39 antibody. A polymerase chain reaction (PCR) specific for the Leishmania kinetoplast minicircle gene was positive, and subsequent sequencing of the PCR-amplified product confirmed that this case was a L. donovani infection. The patient was treated with miltefosine for 28 days, during which time the response was good, and the Leishman-Donovan body (LD body) was negative on discharge. Ten months later, however, this patient again developed high fever and splenomegaly, and LD bodies and rK39 antibody were positive, thus indicating a relapse of VL. The patient was subsequently treated with 1 mg/kg of amphotericin B for a total of 14 days and recovered completely.
TL;DR: New aspects of established compounds and on new drugs such as miltefosine and the combination of traditional compounds with immunomodulators are focused on.
Abstract: Leishmaniasis is an infection caused by intracellular protozoan parasites of the genus Leishmania and it is transmitted by various species of sand flies. Apart from disseminated visceral leishmaniasis (kala azar), nodules, patches/plaques, ulcerative skin lesions, and destructive mucosal inflammation comprise the wide range of clinical manifestations. With regard to cutaneous leishmaniasis (CL) and mucosal leishmaniasis (ML), the parasite species are divided into Old World (Southern Europe, the Middle East, Asia, and Africa) and New World leishmaniasis (Latin America). While most of the Old World species cause benign cutaneous disease, a variety ranging from mild cutaneous disease to severe mucosal lesions is seen among the American species.
CL is one of the 10 leading presentation diseases among tourists from tropical countries with skin diseases and was found in 3% of travelers with skin disorders. 1 Because of the broad clinical spectrum of CL and resemblance with common skin diseases such as bacterial or fungal infections and tumors, the correct diagnosis is initially often missed. However, a delayed diagnosis may lead to mucosal spread. Furthermore, treatment of the various species may be different and a suboptimal treatment may cause a prolonged course of the disease and may be associated with disfiguring scars. 2,3
The broad availability of polymerase chain reaction (PCR) allows a rapid determination of species. A species‐specific treatment approach has been evaluated for many species and is widely applied in many centers. 4–9 These treatment options need to be regularly adapted integrating new knowledge and data. This manuscript focuses on new aspects of established compounds and on new drugs such as miltefosine and the combination of traditional compounds with immunomodulators. Recent data focusing on genetic differences of individual species between regions are integrated and region‐specific treatment recommendations for Leishmania braziliensis 10,11 and Leishmania guyanensis 12 CL are given.
In many …
Corresponding Author: Johannes Blum, MD, DTM&H, Medical Department Swiss Tropical Institute, Socinstrasse 57, CH 4002 Basel, Switzerland. E‐mail:johannes.blum{at}unibas.ch
TL;DR: IFT and TRALd presented the best performance to diagnose classic cases of visceral leishmaniasis in an endemic area and differences in the positivity of the tests used, together with the low agreement between results, do not permit to select the best test for the diagnosis of asymptomatic Leishmania infection.
Abstract: Serologic tests have been widely used for the diagnosis of asymptomatic visceral leishmaniasis. This study evaluated five serologic tests used for the diagnosis of asymptomatic infection: enzyme-linked immunosorbent assay (ELISA) using promastigote antigen (ELISAp), ELISA using recombinant K39 (ELISA rK39), and K26 (ELISA rK26) antigens, an indirect immunofluorescence test using Leishmania (Leishmania) amazonensis promastigote antigen (IIFT), and an immunochromatographic test using rK39 antigen (TRALd). As a reference regarding the performance of the tests, patients with classic visceral leishmaniasis originating from Minas Gerais, Brazil (N = 36), were defined as the positive group and samples of healthy individuals from nonendemic areas (Argentina) (N = 127) were used as negative controls. Patients with other diseases such as cutaneous leishmaniasis (N = 53) and malaria (N = 56) were also studied to evaluate the chance of cross-reactivity in these tests. Finally, subjects from an area endemic for visceral leishmaniasis in Brazil (Porteirinha, northern Minas Gerais) (N = 1241) were screened for asymptomatic infection with Leishmania and Chagas disease. The sensitivity of the serologic tests was 50% (18/36), 66.7% (24/36), 69.4% (25/36), 83.3% (30/36), and 88.9% (32/36) for ELISAp, ELISA rK26, ELISA rK39, IIFT, and TRALd, respectively. Specificity, calculated using the truly negative group, was 96% (122/127) for TRALd, 97.6% (124/127) for ELISAp and IIFT, and 100% (127/127) for ELISA rK39 and rK26. Positivity in at least one test employing recombinant antigen was observed in 24 (45%) patients with cutaneous leishmaniasis and 47 (82.4%) with malaria. In the visceral leishmaniasis-endemic area, the positivity of the serologic tests ranged from 3.9% to 37.5%. The enzyme-linked immunosorbent assay (ELISA) tests using recombinant antigens were more frequently positive in subjects with a history of exposure to human or canine visceral leishmaniasis (ELISArK39: 14.6% [149/1017] versus 37.5% [84/224]; ELISA rK26: 12.7% [129/1017] versus 21.4% [48/224], P < 0.001 for both). Kappa agreement was low, with a maximum value of 0.449 between ELISAp and IIFT. In addition, among the 112 IIFT-positive subjects, 75 (67%) also presented positive serology for Chagas disease. In conclusion, IIFT and TRALd presented the best performance to diagnose classic cases of visceral leishmaniasis in an endemic area. Cross-reactivity of the tests with Chagas disease, cutaneous leishmaniasis, and malaria should be taken into account. However, the differences in the positivity of the tests used, together with the low agreement between results, do not permit to select the best test for the diagnosis of asymptomatic Leishmania infection.
TL;DR: Results indicate that a higher quantity of Leishmania DNA was found in the lymph nodes of dogs characterized by maximum clinical score, indicating the presence of a positive relationship betweenLeishmania load and clinical manifestations in dogs showing a severe clinical form of leishmaniasis.
TL;DR: A novel etiological agent of cutaneous leishmaniasis in horses that, at least for some cases, sporadically appeared as autochthonous infections in geographically distant regions of Germany and Switzerland is described.
TL;DR: Between August 1997 and February 2005, a prospective study of human visceral leishmaniasis was undertaken in two villages in the Konso district of south–western Ethiopia, to provide epidemiological indices of subclinical infection and active VL.
Abstract: Between August 1997 and February 2005, a prospective study of human visceral leishmaniasis (VL) was undertaken in two villages in the Konso district of south-western Ethiopia, to provide epidemiological indices of subclinical infection and active VL. Six cross-sectional surveys at 6-month intervals (ending in August 2000) were complemented by a single survey in February 2005. The prevalences and incidences of leishmanial infection and active VL, which were determined using leishmanin skin tests (LST), direct agglutination tests (DAT) and parasitological diagnosis, varied spatio-temporally and by age and gender. At baseline, when 1339 individuals were investigated, the overall prevalences of LST positivity, DAT positivity and active VL among the 1232 subjects who had not been treated previously were 30.0%, 5.4% and 0.49%, respectively. During the study, <10% of the subjects found DAT-positive at baseline progressed to active VL (with a mean of about nine cases of subclinical infection for every one of active VL). The median age of an incident VL case was 10.5 years. The highest rates of LST conversion occurred among the subjects aged 5-25 years. A subject who became LST-positive during the study was much less likely to develop active VL than the other subjects.
TL;DR: The existence of transplacental transmission of Leishmania between dogs is confirmed by PCR and immunohistochemistry techniques in samples from spleen and liver of two stillborn pups from a bitch naturally infected with L. infantum in Belo Horizonte city, endemic area of VL.