Ecological aspects of the sandfly fauna (Diptera, Psychodidae) in an American cutaneous leishmaniasis endemic area under the influence of hydroelectric plants in Paranapanema river, State of Paraná, Brazil

INTRODUCTION: An epidemiological study was undertaken to identify determinant factors in the occurrence of American cutaneous leishmaniasis in areas under the influence of hydroelectric plants in Paranapanema river, State of Paraná, Brazil. The ecological aspects of the phlebotomine fauna were investigated. METHODS: Sandflies were sampled with automatic light traps from February 2004 to June 2006 at 25 sites in the urban and rural areas of Itambaracá, and in Porto Almeida and São Joaquim do Pontal. RESULTS: A total of 3,187 sandflies of 15 species were captured. Nyssomyia neivai predominated (34.4%), followed by Pintomyia pessoai (32.6%), Migonemyia migonei (11.6%), Nyssomyia whitmani (8.8%), and Pintomyia fischeri (2.7%), all implicated in the transmission of Leishmania. Males predominated for Ny. neivai, and females for the other vector species, with significant statistical differences (p < 0.001). Nyssomyia neivai, Pi. pessoai, Ny. whitmani, Brumptomyia brumpti, Mg. migonei, and Pi. fischeri presented the highest values for the Standardized Species Abundance Index (SSAI). The highest frequencies and diversities were found in the preserved forest in Porto Almeida, followed by forests with degradation in São Joaquim do Pontal and Vila Rural. CONCLUSIONS: Sandflies were captured in all localities, with the five vectors predominating. Ny. neivai had its highest frequencies in nearby peridomestic environments and Pi. pessoai in areas of preserved forests. The highest SSAI values of Ny. neivai and Pi. pessoai reflect their wider dispersion and higher frequencies compared with other species, which seems to indicate that these two species may be transmitting leishmaniasis in the area.

Space-time cluster analysis of American visceral leishmaniasis in Bauru, São Paulo State, Brazil

A space-time analysis of American visceral leishmaniasis (AVL) in humans in the city of Bauru, São Paulo State, Brazil was carried out based on 239 cases diagnosed between June 2003 and October 2008. Spatial analysis of the disease showed that cases occurred especially in the city's urban areas. AVL annual incidence rates were calculated, demonstrating that the highest rate occurred in 2006 (19.55/100,000 inhabitants). This finding was confirmed by the time series analysis, which also showed a positive tendency over the period analyzed. The present study allows us to conclude that the disease was clustered in the Southwest side of the city in 2006, suggesting that this area may require special attention with regard to control and prevention measures.

Visceral leishmaniasis in Brazil: trends and challenges

The urbanization of visceral leishmaniasis in Brazil has been related to environmental changes, migration, interaction and spread of sylvatic reservoirs and infected dogs to areas with no transmission, and adaptation of the vector Lutzomyia longipalpis to the peridomiciliary environment. From 1980 to 2005, Brazil recorded 59,129 cases of visceral leishmaniasis, 82.5% of which in the Northeast region. Visceral leishmaniasis gradually spread to other regions of the country: in 1998 these other regions reported 15% of all cases, but by 2005 this proportion had increased to 44%. From 1998 to 2005, indigenous cases were reported in 1,904 different municipalities of the country (34.2%). Reservoir and vector control pose major challenges for disease control, since there is a need for better knowledge of vector behavior in urban areas, and control activities involve high operational costs. In recent years the Brazilian Ministry of Health has supported research on the laboratory diagnosis of infection and disease in humans and dogs, treatment of patients, evaluation of the effectiveness of control strategies, and development of new technologies that could contribute to the surveillance and control of visceral leishmaniasis in the country.

Epidemiological aspects of American cutaneous leishmaniasis and phlebotomine sandfly population, in the municipality of Monte Negro, State of Rondônia, Brazil

INTRODUCTION: This work was carried out on the purpose of identifying the species of phlebotomine sandflies in the municipality of Monte Negro, state of Rondonia, Brazil, that may have been transmitting the American cutaneous leishmaniasis (ACL), and concisely describe epidemiological aspects of disease. METHODS: The epidemiologic and socioeconomical indicators were obtained from government institutions and the local Municipal Secretary of Health. Phlebotomine sandflies were captured using CDC light traps between July 2006 to July 2008. The total of 1,240 of female sandflies were examined by PCR method directed to k-DNA. RESULTS: There has been a significant decrease in the incidence of ACL of about 50% over the last ten years in the municipality. A total of 1,935 specimens of 53 sandfly species were captured, three of the genus Brumptomyia genus and 50 of the genus Lutzomyia. The predominant species was Lutzomyia acanthopharynx, Lutzomyia whitmani, Lutzomyia geniculata and Lutzomyia davisi. None were positive for Leishmania sp. CONCLUSIONS: Four sandflies species were found in the State of Rondonia for the first time: Brumptomyia brumpti, Lutzomyia tarapacaensis, Lutzomyia melloi and Lutzomyia lenti. The presence of Lutzomyia longipalpis, was also captured. Socioeconomical improvement of Brazilian economy and the increase of environmental surveillance in the last 15 years collaborated in the decrease of people exposed to vectors, reducing the incidence of ACL.

USEFULNESS OF kDNA PCR IN THE DIAGNOSIS OF VISCERAL LEISHMANIASIS REACTIVATION IN CO-INFECTED PATIENTS

It is important to develop new methods for diagnosing relapses in the co-infection of visceral leishmaniasis (VL) and HIV to enable earlier detection using less invasive methods. We report a case of a co-infected patient who had relapses after VL treatment, where the qualitative kDNA PCR showed a good performance. The kDNA PCR seems to be a useful tool for diagnosing VL and may be a good marker for predicting VL relapses after treatment of co-infected patients with clinical symptoms of the disease.

Anti-Leishmania infantum IgG Antibody Avidity in Visceral Leishmaniasis

IgG avidity tests are used to discriminate acute from chronic infections. There are few reports on the IgG avidity profile of patients with visceral leishmaniasis (VL). This study investigated the anti-Leishmania IgG avidity in patients with classic VL (n = 10), patients showing clinical cure after treatment (n = 18), and asymptomatic subjects with at least one positive Leishmania test (n = 20). All subjects were from areas in Brazil where VL is endemic. Serum samples were collected from each subject on two different occasions. IgG avidity was evaluated by Western blotting. The proportion of high-avidity antibodies was higher in all samples from patients with classic VL. In contrast, low-avidity antibodies predominated in subjects with a history of VL, including 13 cases (72.2%) in the first assessment and 14 (77.8%) in the second. Fifteen (75%) of the asymptomatic subjects presented a predominance of low-avidity antibodies in the first assessment, and the frequency of high-avidity antibodies increased over time in seven subjects (35%) of this group. Antibodies against the 14- and/or 16-kDa antigen fraction were detected in the first assessment in all patients with classic VL, in 10 (55.5%) treated patients, and in 10 (50%) asymptomatic subjects. These were high-avidity antibodies in most cases. In the asymptomatic group, an increase in IgG avidity against the 14- and/or 16-kDa antigen fraction was observed in three cases (15%). The results indicate distinct responses in infected and asymptomatic subjects, probably associated with the length of time after infection. In this respect, IgG avidity tests represent a new approach to better characterize asymptomatic VL.

Studying MHC I-dependent CD8 + T cell responses in the model of murine cutaneous leishmaniasis

Der Ausheilung von Infektionen mit Leishmania major liegt die Sekretion von IFN- von sowohl CD4+ als auch CD8+ T Zellen zugrunde.rnAktuell konnte in der Literatur nur ein Epitop aus dem parasitären LACK Protein für eine effektive CD4+ T Zell-vermittelte Immunantwort beschrieben werden. Das Ziel der vorliegenden Arbeit bestand daher darin, mögliche MHC I abhängige CD8+ T Zell Antworten zu untersuchen. rnFür diesen Ansatz wurde als erstes der Effekt einer Vakzinierung mit LACK Protein fusioniert an die Protein-Transduktionsdomäne des HIV-1 (TAT) analysiert. Die Effektivität von TAT-LACK gegenüber CD8+ T Zellen wurde mittels in vivo Protein-Vakzinierung von resistenten C57BL/6 Mäusen in Depletions-Experimenten gezeigt.rnDie Prozessierung von Proteinen vor der Präsentation immunogener Peptide gegenüber T Zellen ist unbedingt erforderlich. Daher wurde in dieser Arbeit die Rolle des IFN--induzierbaren Immunoproteasoms bei der Prozessierung von parasitären Proteinen und Präsentation von Peptiden gebunden an MHC I Moleküle durch in vivo und in vitro Experimente untersucht. Es konnte in dieser Arbeit eine Immunoproteasom-unabhängige Prozessierung aufgezeigt werden.rnWeiterhin wurde Parasitenlysat (SLA) von sowohl Promastigoten als auch Amastigoten fraktioniert. In weiterführenden Experimenten können diese Fraktionen auf immunodominante Proteine/Peptide hin untersucht werden. rnLetztlich wurden Epitop-Vorhersagen für CD8+ T Zellen mittels computergestützer Software von beiden parasitären Lebensformen durchgeführt. 300 dieser Epitope wurden synthetisiert und werden in weiterführenden Experimenten zur Charakterisierung immunogener Eigenschaften weiter verwendet. rnIn ihrer Gesamtheit trägt die vorliegende Arbeit wesentlich zum Verständnis über die komplexen Mechanismen der Prozessierung und letztendlich zur Identifikation von möglichen CD8+ T Zell Epitopen bei. Ein detailiertes Verständnis der Prozessierung von CD8+ T Zell Epitopen von Leishmania major über den MHC Klasse I Weg ist von höchster Bedeutung. Die Charakterisierung sowie die Identifikation dieser Peptide wird einen maßgeblichen Einfluss auf die weiteren Entwicklungen von Vakzinen gegen diesen bedeutenden human-pathogenen Parasiten mit sich bringen. rn

Untersuchung von T-Zell-vermittelten Immunantworten in der murinen und humanen kutanen Leishmaniasis

Für die Ausheilung von L. major-Infektionen ist eine effektive Th1-/Tc1-Antwort unerlässlich. Dennoch sind bis heute nicht alle Mechanismen der schützenden Immunabwehr beim Menschen und in der Maus endgültig geklärt. Deshalb bestand das Ziel der vorliegenden Arbeit darin, Th1-/Tc1-Antworten und damit die Schnittstelle zwischen angeborenem und adaptivem Immunsystem eingehender zu untersuchen. Für diesen Ansatz wurde zunächst der Einfluss des genetischen Hintergrundes auf den Verlauf der Infektion anhand von BALB/c- und C57BL/6-Zellen analysiert. Als entscheidender Faktor für Heilung und Suszeptibilität wurde mit Hilfe von Knochenmarkschimären die Herkunft der T und/oder B Zellen identifiziert. Erst die Aktivierung durch Th1-/Tc1-Zellen versetzt L. major-infizierte Makrophagen in die Lage, die intrazellulären Parasiten abzutöten. In diesem Aktivierungsprozess spielt die TNF-induzierte Signalweiterleitung über den TNF-Rezeptor 1 (TNF-R1) eine wichtige Rolle. TNF-R1 ist mit dem Signalmolekül FAN assoziiert. In dieser Arbeit konnte anhand von Mäusen, denen FAN fehlt, die Involvierung dieses Moleküls in der Induktion eines Th1-Zytokinsprofils und in der Kontrolle der Parasitenzahl sowie der lokalen Begrenzung der Infektion gezeigt werden. Weiterhin wurde unter Verwendung immundefizienter Mäuse die Realisierbarkeit eines PBMC-Transfermodells geprüft. Ein solches wird zur Validierung an Mäusen gewonnener Erkenntnisse und als präklinisches Testsystem der humanen kutanen Leishmaniasis dringend benötigt. In allen getesteten Stämmen ließ sich durch den Transfer humaner PBMC die L. major-Infektion beeinflussen. Humane CD4+ und CD8+ T-Zellen waren an den Infektionsstellen präsent und es konnten antigenspezifische Immunreaktionen nnachgewiesen werden. Das PBMC-Transfermodell konnte durch die Transplantation humaner Haut auf immundefiziente Mäuse zusätzlich entscheidend verbessert werden. In diesen Transplantaten ließen sich L. major-Infektionen etablieren und durch zusätzlichen Transfer von PBMC die Zahl humaner CD45+ Zellen an der Infektionsstelle deutlich steigern. In ihrer Gesamtheit trägt die vorliegende Arbeit wesentlich zum Verständnis der Determinanten von Heilung und Suszeptibilität der kutanen Leishmaniasis bei und zeigt neue Ansatzpunkte für eine Beeinflussung des Krankheitsverlaufes auf. Die Etablierung eines präklinischen Testmodells der humanen Leishmaniasis ist entscheidend, um das Wissen über die murine Leishmaniasis auf die humane Erkrankung zu übertragen. So kann dem dauerhaften Problem der Entwicklung von Vakzinen an Mäusen, die keine Wirksamkeit gegen die humane Erkrankung zeigen, begegnet werden. Ein vollständig etabliertes Modell wird es ermöglichen, der humanen Erkrankung zugrundeliegende Mechanismen zu untersuchen und Patienten-spezifisch aber auch allgemeingültig Vakzinierungs-Ansätze und Therapien unter experimentellen Bedingungen zu testen.

An autochthonous case of cutaneous bovine leishmaniasis in Switzerland

The present case report describes a novel etiological agent of cutaneous leishmaniasis that appears for the first time in a cow. A similar agent had recently been described as causing autochthonous infections in horses of Germany and Switzerland. The infection in the cow was initially diagnosed upon clinical and immunohistological findings. Subsequent comparative sequence analysis of diagnostic PCR products from the internal transcribed spacer 1 (ITS1) of ssrRNA classified the respective isolate as neither Old World nor New World Leishmania species, but yielded complete identity of the analysed sequence with the above mentioned horse cases and 98% identity to Leishmania sp. siamensis, an organism recently identified in a visceral leishmaniasis patient from Thailand. The potential transmitting vectors for all these cases have not yet been identified. Future investigations will have to elucidate the veterinary-epidemiological relevance of this etiological agent, as well as biological parameters such as transmission mode and geographical origin and distribution.

Holiday souvenirs from the Mediterranean: three instructive cases of visceral leishmaniasis

With expanding travel activities, visceral leishmaniasis increasingly occurs in non-endemic areas and affects immunocompetent individuals with no other risk factor than holidays at the Mediterranean coast. We report 3 instructive Swiss cases of visceral leishmaniasis presenting with fever of unknown origin and pancytopenia and review current diagnostic and therapeutic concepts.

Is paromomycin an effective and safe treatment against cutaneous leishmaniasis? A meta-analysis of 14 randomized controlled trials.

BACKGROUND: High cost, poor compliance, and systemic toxicity have limited the use of pentavalent antimony compounds (SbV), the treatment of choice for cutaneous leishmaniasis (CL). Paromomycin (PR) has been developed as an alternative to SbV, but existing data are conflicting. METHODOLOGY/PRINCIPAL FINDINGS: We searched PubMed, Scopus, and Cochrane Central Register of Controlled Trials, without language restriction, through August 2007, to identify randomized controlled trials that compared the efficacy or safety between PR and placebo or SbV. Primary outcome was clinical cure, defined as complete healing, disappearance, or reepithelialization of all lesions. Data were extracted independently by two investigators, and pooled using a random-effects model. Fourteen trials including 1,221 patients were included. In placebo-controlled trials, topical PR appeared to have therapeutic activity against the old world and new world CL, with increased local reactions, when used with methylbenzethonium chloride (MBCL) compared to when used alone (risk ratio [RR] for clinical cure, 2.58 versus 1.01: RR for local reactions, 1.60 versus 1.07). In SbV-controlled trials, the efficacy of topical PR was not significantly different from that of intralesional SbV in the old world CL (RR, 0.70; 95% confidence interval, 0.26-1.89), whereas topical PR was inferior to parenteral SbV in treating the new world CL (0.67; 0.54-0.82). No significant difference in efficacy was found between parenteral PR and parenteral SbV in the new world CL (0.88; 0.56-1.38). Systemic side effects were fewer with topical or parenteral PR than parenteral SbV. CONCLUSIONS/SIGNIFICANCE: Topical PR with MBCL could be a therapeutic alternative to SbV in selected cases of the old world CL. Development of new formulations with better efficacy and tolerability remains to be an area of future research.

Leishmaniasis and polyarthritis in the dog

Two cases of polyarthritis in the dog resulting from Leishmania species infection are reviewed. The clinical investigations, laboratory findings and serological tests are summarised. Leishmanial amastigotes were detected in synovial fluid samples of multiple joints with marked inflammatory signs. Diagnosis was made by biopsy of bone marrow, skin and synovial fluid. Both dogs were initially treated with pentavalent sodium stibogluconate. Other causes of canine polyarthritis were excluded.

Quantitative PCR for the diagnosis of cutaneous leishmaniasis from formalin-fixed and paraffin-embedded skin sections.

The present report describes a real-time PCR-based procedure to reliably determine the quantity of Leishmania amastigotes in relation to the amount of host tissue in histological skin sections from canine and equine cases of cutaneous leishmaniasis. The novel diagnostic Leishmania-PCR has a detection limit of <0.02 amastigotes per μg tissue, which corresponds well to the detection limit of immunohistochemistry and is far beyond that of conventional histology. Our results emphasise the importance of PCR to complement routine histology of cutaneous leishmaniasis cases, particularly in laboratories in which no immunohistochemical assay is available.

Randomised controlled trial of aminosidine (paromomycin) v sodium stibogluconate for treating visceral leishmaniasis in North Bihar, India

Objectives: To assess the efficacy and tolerability of aminosidine compared with sodium stibogluconate for treating visceral leishmaniasis.