Leishmaniasis In Endemic Area Research Articles

Visceral leishmaniasis in a Brazilian endemic area: an overview of occurrence, HIV coinfection and lethality

ABSTRACTThe Brazilian municipality of Rondonópolis, Mato Grosso State, represents an important visceral leishmaniasis (VL) endemic area. This study described epidemiological and clinical aspects of the occurrence, VL/HIV coinfection and lethality related to VL in Rondonópolis. Data from autochthonous cases reported between 2011 and 2016 were obtained from official information systems. During this period, 81 autochthonous cases were reported, with decreasing incidence through 2016. Contrastingly, the lethality rate was 8.6% overall, but varied widely, reaching a peak (20%) in 2016. Almost 10% of patients had VL/HIVcoinfection. The occurrence of VL prevailed among men (56.8%), brown-skinned (49.4%), urban residents (92.6%), aged 0-4 years (33.3%). Housewives or retired (29.6%) were the most affected occupational groups. Lower age was the main difference among the total VL cases and those who were coinfected or died. Clinically, fever, weakness and splenomegaly were more frequent among all VL cases and VL/HIV coinfected individuals. Bacterial infections (p=0.001) and bleeding (p<0.001) were associated with death due to VL. Pentavalent antimonial and liposomal amphotericin B were the first choices for treatment among all VL cases (71.6%) and those who died (71.4%), respectively. VL/HIV patients were equally treated with both drugs. These findings may support control measures and demonstrate the need for further investigations.

Level of agreement between two commercially available rapid serological tests and the official screening test used to detect Leishmania seropositive dogs in Brazil

This study compared the level of agreement between two commercially available rapid serological tests and the official screening test used to detect Leishmania seropositive dogs in Brazil. Ninety-five canine sera from a visceral leishmaniasis endemic area were tested by using the official immunochromatographic test (T1; rK28 antigen) based on dual path platform technology, a rapid ELISA (T2; purified Leishmania antigens) and an immunochromatographic test (T3; rK28 antigen) based on lateral flow. There was substantial agreement (Kappa 0.77; 95% confidence interval, CI, 0.62–0.91; P<0.001; observed agreement 90.5%) between T1 and T2, and a fair agreement (Kappa 0.26; 95% CI 0.08–0.43; P<0.001; observed agreement 74.7%) between T1 and T3. Sixteen dogs positive at T1 and T2 were negative at T3. T2 may be a reliable alternative to T1, while T3 could lead to an underestimation of the actual number of seropositive dogs.

Leishmania (Viannia) braziliensis isolated from the saliva of patients in a cutaneous leishmaniasis-endemic area of northeastern Brazil.

Several studies have described the use of non-invasive collection methods, mostly based on the detection of parasite DNA, for diagnosis. However, no Leishmania specimens have been isolated from saliva. Here, we report the first isolation of Leishmania braziliensis from the saliva of humans with cutaneous leishmaniasis but without lesions on their mucosa. The isolates were obtained from salivary fluid inoculated in hamsters and were tested by multilocus enzyme electrophoresis. Seven samples from 43 patients suspected of having the disease were identified for in vivo culture. These findings suggest that saliva is a clinical sample that allows the isolation of Leishmania sp.

Molecular detection of Leishmania (Leishmania) infantum in phlebotomine sandflies from a visceral leishmaniasis endemic area in northwestern of São Paulo State, Brazil

This study identified the natural infection rate of Leishmania (Leishmania) infantum in Lutzomyia longipalpis sandflies collected in a neighborhood around a kennel, in Dracena, northwestern of São Paulo state. This region is highly endemic for visceral leishmaniasis in Brazil. Insects were captured during 2–3 nights monthly for 11 months (January–November 2012) using 10 automatic light traps around a kennel in a transition between periurban and urban neighborhood. Capture aimed the determination of the minimal infection rate (MIR) on the area. A total of 1690 Lu. longipalpis were captured during the studied period. Out of them, 292 (17.25%) were females and were grouped in 165 pools containing 1 to five insects for DNA extraction and PCR analysis. Positive results for L. (L) infantum in conventional PCR and real time PCR were shown in 7.28% (12/165) and 4.85% (8/165) of the analysis respectively. These data confirm that Lu. longipalpis captured in the study area were infected by L. (L.) infantum. The MIR of sandflies during the 11 months of captures was 4.10% for female the total of 292 female sandflies collected. A high DNA concentration of L. (L.) infantum was detected on sandflies especially in kennel, chicken coop and neighboring houses, where higher abundance of hosts for blood source were present.

Small Myristoylated Protein-3, Identified as a Potential Virulence Factor in Leishmania amazonensis, Proves to be a Protective Antigen against Visceral Leishmaniasis.

In a proteomics approach conducted with Leishmania amazonensis, parasite proteins showed either an increase or a decrease in their expression content during extensive in vitro cultivation, and were related to the survival and the infectivity of the parasites, respectively. In the current study, a computational screening was performed to predict virulence factors among these molecules. Three proteins were selected, one of which presented no homology to human proteins. This candidate, namely small myristoylated protein-3 (SMP-3), was cloned, and its recombinant version (rSMP-3) was used to stimulate peripheral blood mononuclear cells (PBMCs) from healthy subjects living in an endemic area of leishmaniasis and from visceral leishmaniasis patients. Results showed high interferon-γ (IFN-γ) production and low levels of interleukin 10 (IL-10) in the cell supernatants. An in vivo experiment was then conducted on BALB/c mice, which were immunized with rSMP-3/saponin and later challenged with Leishmania infantum promastigotes. The rSMP-3/saponin combination induced high production of protein-specific IFN-γ, IL-12, and granulocyte-macrophage colony-stimulating factor (GM-CSF) by the spleen cells of the immunized mice. This pattern was associated with protection, which was characterized by a significant reduction in the parasite load in distinct organs of the animals. Altogether, these results have revealed that this new virulence factor is immunogenic in both mice and humans, and have proven its protective efficacy against visceral leishmaniasis in a murine model.

EPIDEMIOLOGICAL STUDY OF CUTANEOUS LEISHMANIASIS IN SOME IRAQI PROVINCES

&#x0D; &#x0D; Background&#x0D; Cutaneous leishmaniasis (CL) remains a serious public health concern in some parts of Iraq. The aims of this study to report of CL in some parts of Iraq, by different parasitological, cultural, and molecular methods and evaluate sex differences among infected patients. This is the first study conducted to characterize Leishmania species causing CL among Iraqi patients using the sequence analysis of Internal Transcribed Spacer1(ITS1) at Wasit Province.&#x0D; Methods&#x0D; A total of 700 cases of suspected CL were referred to the Iraqi clinics and health centres and they checked for Leishmania amastigote using a Giemsa-stain; however, the Novy Macneal Nicolle (NNN) culture led to the growth of promastigotes in all samples, then the samples were examined using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP)-PCR methods.&#x0D; Results&#x0D; The present study indicated that the prevalence of CL as follow: AL-Diwaniyah 88(15.1%), Wasit 85 (14.5%), Najaf 79 (13.6%), Thi-Qar76 (13.1%), Basrah 67 (11.5%), Baghdad 65 (11.2%), Diyala 63(10.8%), and Salah-Edin province which recorded lower infection 60 (10.3%), and it appeared in 83.3% by using Giemsa- smeared stain. The highest infection rate (100%) appeared using PCR while the lowest infection (68%) appeared by culture on NNN media. The present study was revealed that the highest infection (60%) was caused by L.major rather than L.tropica (40%). Our results showed that 368 (52.6%) of CL patients were had single lesion and 215 (30.7%) had multiple lesions, and the ulcerative wet type lesions were present in 49.6%, while the nodule dry type lesions were present in 33.7%. The overall prevalence of cutaneous leishmaniasis in the study area was very high (83.3%) having a statistically significant association with sex; males are more prone (56.4%) to CL as compared to females (43.6%)&#x0D; &#x0D; Conclusions&#x0D; A clear and reliable bias toward males exists in some tropical diseases, such as leishmaniasis. CL is a major health problem in Iraq and CL caused by many countries including Iraq. Health authorities should be aware of the fact that war and terrorist activities induce expansion of the disease and increase the incidence rate in the situation that access to medical treatment is not easy especially in poor conditions in leishmaniasis endemic areas.&#x0D; &#x0D; &#x0D;

Molecular detection of Leishmania species in human and animals from cutaneous leishmaniasis endemic areas of Waziristan, Khyber Pakhtunkhwa, Pakistan

Objectives: To detect Leishmania species in human patients, animal reservoirs and Phlebotomus sandflies in Waziristan, Pakistan. Methods: Tissue smears and aspirates from 448 cutaneous leishmaniasis (CL) suspected patients were analyzed. To sort out role of the reservoir hosts, skin scrapings, spleen and liver samples from 104 rodents were collected. Furthermore, buffy coat samples were obtained from 60 domestic animals. Sandflies were also trapped. All human, animals and sandfly samples were tested by microscopy, kinetoplastic PCR and internal transcribed spacer 1 (ITS1) PCR followed by restriction fragment length polymorphism for detection of Leishmania species. Results: An overall prevalence of 3.83% and 5.21% through microscopy and ITS1 PCR respectively was found. However, the statistically non-significant correlation was found between area, gender, and number of lesions. The presence of rodents, sandflies, domestic animals and internally displaced people increased the risk of CL. Using ITS1-PCR-RFLP, Leishmania tropica (L. tropica) was confirmed in 106 samples while 25 of the isolates were diagnosed as Leishmania major (L. major). Similarly, 3/104 rodents were positive for L. major and 14 pools of DNA samples containing Phlebotomus sergenti sandflies were positive for L. tropica. None of samples from domestic animals were positive for leishmaniasis. Conclusions: In the present study, L. tropica and L. major are found to be the main causative agents of CL in study area. Movement of internally displaced people from CL endemic areas presents a risk for nearby CL free areas. To the best of our knowledge, we report for the first time L. major infection in rodents (Rattus rattus) and L. tropica in Phlebotomus sergenti sandflies trapped in Waziristan, Pakistan.

Detection of Leishmania spp in silvatic mammals and isolation of Leishmania (Viannia) braziliensis from Rattus rattus in an endemic area for leishmaniasis in Minas Gerais State, Brazil.

Knowledge of potential reservoirs of Leishmania spp. in an anthropic environment is important so that surveillance and control measures can be implemented. The aim of this study was to investigate the infection by Leishmania in small mammals in an area located in Minas Gerais, Brazil, that undergoes changes in its natural environment and presents autochthonous human cases of cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL). For the capture of the animals, Sherman and Tomahawk traps were used and distributed in the peridomicile of houses with reports of autochthonous cases of CL or VL. Six catches were carried out on two consecutive nights with intervals of two months during one year and samples of spleen, liver, tail skin, ear skin and bone marrow of the animals were obtained. Parasitological and molecular methods were used to detect the infection. Identification of the Leishmania species was performed by PCR RFLPhsp70. Twenty five animals of four species were captured: ten Rattus rattus, nine Didelphis albiventris, five Cerradomys subflavus and one Marmosops incanus. In the PCR-hsp70, five animals were positive (20%). The Leishmania species identified in PCR-RFLPhsp70 were: Leishmania braziliensis in D. albiventris (2), C. subflavus (1) and R. rattus (1) and Leishmania infantum in R. rattus (1). The highest positivity rate for L. braziliensis was obtained in the liver samples. The spleen was the only tissue positive for L. infantum. It was isolated in culture medium L. braziliensis from two samples (liver and spleen) of R. rattus. This is the first record of isolation of L. braziliensis from R. rattus in the southeastern region of Brazil. These results are relevant to the knowledge of the epidemiology of leishmaniasis in the region, mainly in the investigation of the presence of hosts and possible reservoirs of the parasite.

Leishmaniasis: Who Uses Personal Protection among Military Personnel in Colombia?

BackgroundLeishmaniasis is common in Colombia, negatively affecting the health of military personnel active in endemic areas. The disease is transmitted by sand fly bites. Therefore, during duty, use of long-sleeved uniforms and other clothes treated with permethrin and application of mosquito repellent are important personal preventive measures. ObjectiveThe objective of this study was to assess personal and occupational factors associated with the use of personal protection in male soldiers deployed to Leishmaniasis-endemic areas. MethodsThree hundred soldiers participated in a cross-sectional questionnaire study (response 84.3%). The self-administered questionnaire contained questions about sociodemographics, duration of service, compliance with personal mosquito protection, and knowledge about leishmaniasis. Descriptive analyses were followed by multiple logistic regression models adjusted for potential confounders (EpiInfo Version 7.0) FindingsOverall, 23% of the soldiers reported complete use of the recommended personal protection measures. About 83% of the participants had heard about leishmaniasis. In the adjusted regression model, knowledge about leishmaniasis (adjusted odds ratio = 2.9; 95% confidence interval: 1.1-7.2) and being enrolled in the army for more than 5 years (2.2; 1.1-4.1) increased the odds of using personal protection. ConclusionsImproving knowledge about leishmaniasis is one measure to increase use of personal protection, thereby diminishing the risk of infection.

Exploring spatial and temporal patterns of visceral leishmaniasis in endemic areas of Bangladesh

BackgroundVisceral leishmaniasis is a considerable public health burden on the Indian subcontinent. The disease is highly endemic in the north-central part of Bangladesh, affecting the poorest and most marginalized communities. Despite the fact that visceral leishmaniasis (VL) results in mortality, severe morbidity, and socioeconomic stress in the region, the spatiotemporal dynamics of the disease have largely remained unexplored, especially in Bangladesh.MethodsMonthly VL cases between 2010 and 2014, obtained from subdistrict hospitals, were studied in this work. Both global and local spatial autocorrelation techniques were used to identify spatial heterogeneity of the disease. In addition, a spatial scan test was used to identify statistically significant space-time clusters in endemic locations of Bangladesh.ResultsGlobal and local spatial autocorrelation indicated that the distribution of VL was spatially autocorrelated, exhibiting both contiguous and relocation-type of diffusion; however, the former was the main type of VL spread in the study area. The spatial scan test revealed that the disease had ten times higher incidence rate within the clusters than in non-cluster zones. Both tests identified clusters in the same geographic areas, despite the differences in their algorithm and cluster detection approach.ConclusionThe cluster maps, generated in this work, can be used by public health officials to prioritize areas for intervention. Additionally, initiatives to control VL can be handled more efficiently when areas of high risk of the disease are known. Because global environmental change is expected to shift the current distribution of vectors to new locations, the results of this work can help to identify potentially exposed populations so that adaptation strategies can be formulated.

Phlebotomine sandflies and factors associated with their abundance in the leishmaniasis endemic area of Attiki, Greece.

Leishmaniasis is a parasitic disease of animals and humans caused by several Leishmania species and transmitted by phlebotomine sandflies. The aim of the present study was to identify the species of field collected phlebotomine sandflies in the endemic area of the Attiki during 4 consecutive years, to isolate the Leishmania parasites from the infected sandflies, and identify possible factors associated with sandfly abundance in the area. A total of 542 trappings were made in 46 collection sites, in purely urban areas, periurban areas, and purely rural areas in Attiki. Out of the 3254 sandflies trapped, 1448 (44.43%) were female and 241 (16.64%) of the females were blood fed while Leishmania infantum DNA was detected in the 0.41% of them. Regarding sandfly species, the most prevalent was Phlebotomus tobbi (41.52%) followed by Sergentomyia minuta (27.44%), P. neglectus (14.83%), P. simici (11.08%), P. papatasi (3.68%), P. similis (0.89%), and P. alexandri (0.56%). Periurban areas were found to have the highest density of sandfly populations.

Midgut Bacterial Diversity of Wild Populations of Phlebotomus (P.) papatasi, the Vector of Zoonotic Cutaneous Leishmaniasis (ZCL) in Turkey

Phlebotomine sand flies are hematophagous insects that harbor bacterial, viral and parasitic agents like Bartonella sp., Phleboviruses and Leishmania spp., respectively. There are few reports on bacterial microbiota of Phlebotomus (P.) papatasi but no data available for natural populations of Turkey, where leishmaniasis is endemic. Therefore, we aimed to investigate the midgut bacterial flora of different populations of P. papatasi. Sand flies were collected from different towns (Karaburun, Urla, Ayvacik and Başçayır) located in the western part of Turkey. Laboratory reared P. papatasi were included in the study as an insectarium population. After sterile washing steps, sand flies were dissected and guts were separated. Three pools, (males, unfed females and blood-fed females) were generated for each population. Prokaryotic 16 S rRNA gene was amplified and DGGE was performed. Fourteen different organisms belonging to two Phylum (Proteobactericea and Furmicutes) were identified according to sequence results in the studied pools. The presence of Wolbachia sp. was shown for the first time in the wild-caught sand fly populations of Turkey. This is the first report of gut bacterial flora of wild-caught P. papatasi collected in an endemic area for leishmaniasis in Turkey. Microbiome profiling of wild-caught sand flies will be of great help in the investigating of possible vector control candidates for paratransgenic control approach.

Human cellular and humoral immune responses to Phlebotomus papatasi salivary gland antigens in endemic areas differing in prevalence of Leishmania major infection.

BackgroundSand fly saliva compounds are able to elicit specific immune responses that have a significant role in Leishmania parasite establishment and disease outcome. Characterizing anti-saliva immune responses in individuals living in well defined leishmaniasis endemic areas would provide valuable insights regarding their effect on parasite transmission and establishment in humans.Methodology/Principal findingsWe explored the cellular and humoral immune responses to Phlebotomus (P.) papatasi salivary gland extracts (SGE) in individuals living in cutaneous leishmaniasis (CL) old or emerging foci (OF, EF). OF was characterized by a higher infection prevalence as assessed by higher proportions of leishmanin skin test (LST) positive individuals compared to EF. Subjects were further subdivided into healed, asymptomatic or naïve groups. We showed anti-SGE proliferation in less than 30% of the individuals, regardless of the immune status, in both foci. IFN-γ production was higher in OF and only observed in immune individuals from OF and naïve subjects from EF. Although IL-10 was not detected, addition of anti-human IL-10 antibodies revealed an increase in proliferation and IFN-γ production only in individuals from OF. The percentage of seropositive individuals was similar in immune and naïves groups but was significantly higher in OF. No correlation was observed between anti-saliva immune responses and LST response. High anti-SGE-IgG responses were associated with an increased risk of developing ZCL. No differences were observed for anti-SGE humoral or cellular responses among naïve individuals who converted or not their LST response or developed or not ZCL after the transmission season.Conclusions/SignificanceThese data suggest that individuals living in an old focus characterized by a frequent exposure to sand fly bites and a high prevalence of infection, develop higher anti-saliva IgG responses and IFN-γ levels and a skew towards a Th2-type cellular response, probably in favor of parasite establishment, compared to those living in an emerging focus.

Investigation on some selected vector-borne pathogens and evaluation of co-infections in clinically suspected dogs, in Southern Romania

Serological diagnostic tests for canine and human leishmaniasis present problems related with their sensitivity and/or specificity. Recently, an immunoproteomic approach performed with Leishmania infantum proteins identified new parasite antigens. In the present study, the diagnostic properties of two of these proteins, cytochrome c oxidase and IgE-dependent histamine-releasing factor, were evaluated for the serodiagnosis of canine visceral (CVL) and human tegumentary (HTL) leishmaniasis. For the CVL diagnosis, sera samples from non-infected dogs living in an endemic or non-endemic area of leishmaniasis, sera from asymptomatic or symptomatic visceral leishmaniasis (VL) dogs, from Leish-Tec®-vaccinated dogs, and sera from animals experimentally infected by Trypanosoma cruzi or Ehrlichia canis were used. For the HTL diagnosis, sera from non-infected subjects living in an endemic area of leishmaniasis, sera from active cutaneous or mucosal leishmaniasis patients, as well as those from T. cruzi-infected patients were employed. ELISA assays using the recombinant proteins showed both sensitivity and specificity values of 100% for the serodiagnosis of both forms of disease, with high positive and negative predictive values, showing better diagnostic properties than the parasite recombinant A2 protein or a soluble Leishmania antigen extract. In this context, the two new recombinant proteins could be considered to be used in the serodiagnosis of CVL and HTL.

Insights into the sand fly saliva: Blood-feeding and immune interactions between sand flies, hosts, and Leishmania.

BackgroundLeishmaniases are parasitic diseases present worldwide that are transmitted to the vertebrate host by the bite of an infected sand fly during a blood feeding. Phlebotomine sand flies inoculate into the mammalian host Leishmania parasites embedded in promastigote secretory gel (PSG) with saliva, which is composed of a diverse group of molecules with pharmacological and immunomodulatory properties.Methods and findingsIn this review, we focus on 3 main aspects of sand fly salivary molecules: (1) structure and composition of salivary glands, including the properties of salivary molecules related to hemostasis and blood feeding, (2) immunomodulatory properties of salivary molecules and the diverse impacts of these molecules on leishmaniasis, ranging from disease exacerbation to vaccine development, and (3) use of salivary molecules for field applications, including monitoring host exposure to sand flies and the risk of Leishmania transmission. Studies showed interesting differences between salivary proteins of Phlebotomus and Lutzomyia species, however, no data were ever published on salivary proteins of Sergentomyia species.ConclusionsIn the last 15 years, numerous studies have characterized sand fly salivary proteins and, in parallel, have addressed the impact of such molecules on the biology of the host–sand fly–parasite interaction. The results obtained shall pave the way for the development of field-application tools that could contribute to the management of leishmaniasis in endemic areas.

Diversity and altitudinal distribution of phlebotomine sand flies (Diptera: Psychodidae) in visceral leishmaniasis endemic areas of northwest Ethiopia

BackgroundThe Leishmaniases are caused by the protozoan parasites of the genus Leishmania and are transmitted to humans by the bite of infected female phlebotomine sand flies. Both visceral and cutaneous leishmaniases are widely distributed in different parts of Ethiopia. The aim of this study was to determine the diversity and altitudinal distribution of phlebotomine sand flies from Kafta Humera to Gondar town in northwest Ethiopia. MethodsSeven localities were selected with distinct altitudinal variations between 550m above sea level (m a.s.l) and 2300m a.s.l. In each locality, sand flies were collected using standard CDC light traps and sticky traps during the active sand fly season from December 2012 to May 2013. Shannon-Weiner species diversity index and Jaccard’s coefficient were used to estimate species diversity and similarity between altitudes and localities, respectively. ResultsA total of 89,044 sand flies (41,798 males and 47, 246 females) were collected from the seven localities/towns throughout the study period. Twenty-two species belonging to 11 species in the genus Phlebotomus and 11 species in the genus Sergentomyia were documented. Of these, Sergentomyia clydei (25.87%), S. schwetzi (25.21%), S. africana (24.65%), S. bedfordi (8.89%), Phlebotomus orientalis (6.43%), and S. antennata (4.8%) were the most prevalent species. The remaining 10 Phlebotomus species and six Sergentomyia were less frequent catches. In CDC light trap and sticky trap, higher species diversity and richness for both male and female sand flies was observed at low altitude ranging from 550 to 699m a.s.l in Adebay village in Kafta Humera district whereas low species richness and high evenness of both sexes were also observed in an altitude 1950–2300m a.s.l. ConclusionThe results revealed that the presence of leishmaniasis vectors such as P. orientalis, P. longipes, P. papatasi, and P. duboscqi in different altitudes in northwest Ethiopia. P. orientalis a vector of L. donovani, occurred between altitude 500–1100m a.s.l, the area could be at high risk of VL. P. longipes a vector of L. aethiopica, was recorded in the highland area in Tikil-Dingay and Gondar town, implicating the possibility of CL transmission. Hence, further investigation into vector competence in relation to leishmaniasis (VL and CL) in the region is very vital.

Occurrence of Lutzomyia longipalpis Lutz & Neiva 1912 and Cerdocyon thous Linnaeus 1977, in a visceral leishmaniasis endemic area in Brazil

Cerdocyon thous presents a wide geographic distribution in Brazil and its role as a possible Leishmania infantum reservoir in a visceral leishmaniasis (VL) transmission cycle regardless of dogs (Canis familiaris) has been discussed. From this perspective, this work describes the occurrence and use of the habitat by Cerdocyon thous in a Lutzomyia longipalpis occurrence area Teresina (Piaui − Brazil), VL endemic region. Three specimens of C. thous were monitored with the use of radio telemetry and trails and footprints, seeking to find possible natural dens in order to collect the sanflies from the site. Luminous CDC and Damasceno traps were simultaneously installed at the visited sites, where two specimens of L. longipalpis and one L. termitophila were captured. The identification of the dens and trails, allows us to infer that the dens are not used only by the C. thous. Finding the VL vector in natural C. thous natural dens, reinforces the hypothesis of transmission of Le. infantum in the outskirts of the large urban centers, in a cycle that independs from dogs.

F1 Domain of the Leishmania (Leishmania) donovani Nucleoside Hydrolase Promotes a Th1 Response in Leishmania (Leishmania) infantum Cured Patients and in Asymptomatic Individuals Living in an Endemic Area of Leishmaniasis.

The Leishmania (Leishmania) donovani nucleoside hydrolase NH36 is the main antigen of the Leishmune® vaccine and one of the promising candidates for vaccination against visceral leishmaniasis. The antigenicity of the N-terminal (F1), the central (F2), or the C-terminal recombinant domain (F3) of NH36 was evaluated using peripheral blood mononuclear cells (PBMC) from individuals infected with L. (L.) infantum from an endemic area of visceral leishmaniasis of Spain. Both NH36 and F1 domains significantly increased the PBMC proliferation stimulation index of cured patients and infected asymptomatic individuals compared to healthy controls. Moreover, F1 induced a 19% higher proliferative response than NH36 in asymptomatic exposed subjects. In addition, in patients cured from visceral leishmaniasis, proliferation in response to NH36 and F1 was accompanied by a significant increase of IFN-γ and TNF-α secretion, which was 42–43% higher, in response to F1 than to NH36. The interleukin 17 (IL-17) secretion was stronger in asymptomatic subjects, in response to F1, as well as in cured cutaneous leishmaniasis after NH36 stimulation. While no IL-10 secretion was determined by F1, a granzyme B increase was detected in supernatants from cured patients after stimulation with either NH36 or F1. These data demonstrate that F1 is the domain of NH36 that induces a recall cellular response in individuals with acquired resistance to the infection by L. (L.) infantum. In addition, F1 and NH36 discriminated the IgG3 humoral response in patients with active visceral leishmaniasis due to L. (L.) donovani (Ethiopia) and L. (L.) infantum (Spain) from that of endemic and non-endemic area controls. NH36 showed higher reactivity with sera from L. (L.) donovani-infected individuals, indicating species specificity. We conclude that the F1 domain, previously characterized as an inducer of the Th1 and Th17 responses in cured/exposed patients infected with L. (L.) infantum chagasi, may also be involved in the generation of a protective response against L. (L.) infantum and represents a potential vaccine candidate for the control of human leishmaniasis alone, or in combination with other HLA epitopes/antigens.

Environmental factors associated with the distribution of visceral leishmaniasis in endemic areas of Bangladesh: modeling the ecological niche

BackgroundVisceral leishmaniasis (VL) is a parasitic infection (also called kala-azar in South Asia) caused by Leishmania donovani that is a considerable threat to public health in the Indian subcontinent, including densely populated Bangladesh. The disease seriously affects the poorest subset of the population in the subcontinent. Despite the fact that the incidence of VL results in significant morbidity and mortality, its environmental determinants are relatively poorly understood, especially in Bangladesh. In this study, we have extracted a number of environmental variables obtained from a range of sources, along with human VL cases collected through several field visits, to model the distribution of disease which may then be used as a surrogate for determining the distribution of Phlebotomus argentipes vector, in hyperendemic and endemic areas of Mymensingh and Gazipur districts in Bangladesh. The analysis was carried out within an ecological niche model (ENM) framework using a maxent to explore the ecological requirements of the disease.ResultsThe results suggest that VL in the study area can be predicted by precipitation during the warmest quarter of the year, land surface temperature (LST), and normalized difference water index (NDWI). As P. argentipes is the single proven vector of L. donovani in the study area, its distribution could reasonably be determined by the same environmental variables. The analysis further showed that the majority of VL cases were located in mauzas where the estimated probability of the disease occurrence was high. This may reflect the potential distribution of the disease and consequently P. argentipes in the study area.ConclusionsThe results of this study are expected to have important implications, particularly in vector control strategies and management of risk associated with this disease. Public health officials can use the results to prioritize their visits in specific areas. Further, the findings can be used as a baseline to model how the distribution of the disease caused by P. argentipes might change in the event of climatic and environmental changes that resulted from increased anthropogenic activities in Bangladesh and elsewhere.

Detection of Leishmania (V) guyanensis in Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) collected from Pecari tajacu.

Previous studies identified the presence of Leishmania infantum in Rhipicephalus sanguineus and indicated the possibility that it could transmit leishmaniasis to a variety of hosts. To identify parasites of Leishmania (Viannia) spp. in ticks collected from wild animals in an endemic area for leishmaniasis. We performed 81 individual DNA extractions from ticks collected from three Tapirus terrestris and three Pecari tajacu in Madre de Dios, Perú. Ticks were taxonomically identified and they were subsequently prepared to identify Leishmania (Viannia) spp. kDNA by PCR and the species of Leishmania by HRM-PCR. Leishmania (Viannia) kDNA was detected in three wild ticks of the species R. microplus, collected from a collard peccary (P. tajacu) hunted in the forests of Madre de Dios. The HRM-PCR showed that one of the positive samples had a kDNA curve compatible with L. (V) guyanensis. The results showed the presence of L. (V) guyanensis DNA in R. microplus possibly acquired after biting a collarde peccary. Therefore, it is important to design future studies to clarify R. microplus involvement in the transmission of leishmaniasis.