10 research outputs found

    Expropriated from the hereafter: the fate of the landless in the Southern Highlands of Madagascar

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    During the period following the abolition of slavery by the French colonial government in 1896, the Southern Highlands of Madagascar was settled by ex-slaves. These early settlers constructed a foundation myth of themselves as tompon-tany, or 'masters of the land', a discourse not only equating land with tombs, kinship and ancestors, but also coupled with a skilful deployment of 'Malagasy customs'. In order to exclude later migrants who also wanted to settle, the 'masters of the land' attempted to establish control over holdings in the area. To this end, and to reinforce their own legitimacy as landholders, the tompon-tany labelled subsequent migrants andevo ('lave' or of 'slave descent') who - as a tombless people - have no rights to land. Because they have neither tombs nor ancestors, the landless andevo are socially ostracised and economically marginalised. As an 'impure people', they are not entitled to a place in the hereafter

    Replacement of Leishmania (Leishmania) infantum populations in an endemic focus of visceral Leishmaniasis in Brazil

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    Visceral leishmaniasis is an important global health problem with an estimated of 50,000 to 90,000 new cases per year. VL is the most serious form of leishmaniasis as it can be fatal in 95% of the cases if it remains untreated. VL is a particularly acute problem in Brazil which contributed with 97% of all cases reported in 2020 in the Americas. In this country, VL affects mainly the poorest people in both urban and rural areas and continues to have a high mortality rate estimated around 8.15%. Here, we performed a temporal parasite population study using whole genome sequence data from a set of 34 canine isolates sampled in 2008, 2012 and 2015 from a re-emergent focus in Southeastern Brazil. Our study found the presence of two distinct sexual subpopulations that corresponded to two isolation periods. These subpopulations diverged hundreds of years ago with no apparent gene flow between them suggesting a process of rapid replacement during a two-year period. Sequence comparisons and analysis of nucleotide diversity also showed evidence of balancing selection acting on transport-related genes and antigenic families. To our knowledge this is the first population genomic study showing a turn-over of parasite populations in an endemic region for leishmaniasis. The complexity and rapid adaptability of these parasites pose new challenges to control activities and demand more integrated approaches to understand this disease in New World foci

    Immunogenic mapping of rDyn-1 and rKDDR-plus proteins and selection of oligopeptides by immunoblotting for the diagnosis of Leishmania infantum-infected dogs

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    Endemic in Brazil, visceral leishmaniasis (VL) is a zoonotic infection that is among the most important parasitic diseases transmitted by vectors. Dogs are the main reservoirs of canine leishmaniasis (CanL) and their identification is used in some countries as part of disease prevention and control measures in the canine and human population. In this context, serological tests are necessary, composed of antigens capable of correctly identifying infected dogs, minimizing the number of false-negative cases. This study aimed to identify more immunoreactive peptides derived from two previously described whole proteins (rDyn-1 and rKDDR-plus) and compare their performance to the control antigens rK39 and the crude extract for the detection of dogs infected with L. infantum, especially the asymptomatic ones. The three selected peptides and a mixture of them, along with the rDyn-1, rKDDR-plus, rK39, and crude extract antigens were evaluated using indirect ELISA with sera samples from 186 dogs with CanL, being asymptomatic (n = 50), symptomatic (n = 50), co-infected (n = 19), infected with Babesia sp. (n = 7), Ehrlichia sp. (n = 6), T. cruzi (n = 20) and uninfected (n = 34). The results showed that the rDyn-1 protein and the peptide mixture had the highest sensitivity (100% and 98.32%, respectively) and specificity (97.01 and 98.51, respectively). A high degree of kappa agreement was found for rDyn-1 protein (0.977), mixed peptides (0.965), rKDDR-plus protein (0.953), K-plus peptide 1 (0.930) and Dyn-1 peptide (0.893). The mixture of peptides showed the highest likelihood (65.87). The ELISA using the mixture of peptides and the rDyn-1 protein showed high performance for CanL serodiagnosis. More mix combinations of the peptides and additional extended field tests with a larger sample size are recommended

    Nanoformulations with Leishmania braziliensis Antigens Triggered Controlled Parasite Burden in Vaccinated Golden Hamster (Mesocricetus auratus) against Visceral Leishmaniasis

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    Leishmaniasis is a widespread vector-borne disease in Brazil, with Leishmania (Leishmania) infantum as the primary etiological agent of visceral leishmaniasis (VL). Dogs are considered the main reservoir of this parasite, whose treatment in Brazil is restricted to the use of veterinary medicines, which do not promote a parasitological cure. Therefore, efficient vaccine development is the best approach to Canine Visceral Leishmaniasis (CVL) control. With this in mind, this study used hamsters (Mesocricetus auratus) as an experimental model in an anti-Leishmania preclinical vaccine trial to evaluate the safety, antigenicity, humoral response, and effects on tissue parasite load. Two novel formulations of nanoparticles made from poly(D, L-lactic) acid (PLA) polymer loading Leishmania braziliensis crude antigen (LB) exhibiting two different particle sizes were utilized: LBPSmG (570 nm) and LBPSmP (388 nm). The results showed that the nanoparticles were safe and harmless to hamsters and were antigenic with the induction in LBSap, LBPSmG, and LBPSmG groups of total anti-Leishmania IgG antibodies 30 days after challenge, which persists 200 days in LBSap and LBPSmP. At the same time, a less pronounced hepatosplenomegaly in LBSap, LBPSmG, and LBPSmP was found when compared to control groups, as well as a less pronounced inflammatory infiltrate and granuloma formation in the spleen. Furthermore, significant reductions of 84%, 81%, and 90% were observed in spleen parasite burden accessed by qPCR in the LBSap, LBPSmG, and LBPSmP groups, respectively. In this way, LBSap, LBPSmG, and LBPSmP formulations showed better results in vaccinated and L. infantum-challenged animals in further reducing parasitic load in the spleen and attenuating lesions in liver and splenic tissues. This results in safe, harmless nanoformulation vaccines with significant immunogenic and infection control potential. In addition, animals vaccinated with LBPSmP had an overall reduction in parasite burden in the spleen, indicating that a smaller nanoparticle could be more efficient in targeting antigen-presenting cells

    Vaccination with Formulation of Nanoparticles Loaded with <i>Leishmania amazonensis</i> Antigens Confers Protection against Experimental Visceral Leishmaniasis in Hamster

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    Visceral leishmaniasis (VL) is a fatal disease caused by the protozoa Leishmania infantum for which dogs are the main reservoirs. A vaccine against canine visceral leishmaniasis (CVL) could be an important tool in the control of human and CVL by reducing the infection pressure of L. infantum. Despite the CVL vaccine available on the market, the Brazilian Ministry of Health did not implement the use of it in their control programs. In this sense, there is an urgent need to develop more efficient vaccines. In this study, the association between two polymeric nanoformulations, (poly (D, L-lactic) acid (PLA) polymer) loading Leishmania amazonensis antigens, was evaluated as a potential immunobiological agent against VL using golden hamsters as an experimental model. The results indicated that no significant adverse reactions were observed in animals vaccinated with LAPSmP. LAPSmP presented similar levels of total anti-Leishmania IgG as compared to LAPSmG. The LAPSmP and LAPSmG groups showed an intense reduction in liver and spleen parasitic load by qPCR. The LAPSmP and LAPSmG vaccines showed exceptional results, indicating that they may be promising candidates as a VL vaccine

    Advances in Polynesian prehistory: A review and assessment of the past decade (1993-2004)

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    The pace of archaeological research in Polynesia has intensified in recent years, resulting in more than 500 new literature citations over the past decade. Fieldwork has continued in such previously well-studied archipelagoes as Tonga and Samoa in Western Polynesia, and Hawai'i and New Zealand in Eastern Polynesia, and has expanded into previously neglected islands including Niue, the Equatorial Islands, the Austral Islands, and Mangareva. The emergence of Ancestral Polynesian culture out of its Eastern Lapita predecessor is increasingly well understood, and the chronology of Polynesian dispersal and expansion into Eastern Polynesia has engaged several researchers. Aside from these fundamental issues of origins and chronology, major research themes over the past decade include (1) defining the nature, extent, and timing of long-distance interaction spheres, particularly in Eastern Polynesia; (2) the impacts of human colonization and settlement on island ecosystems; (3) variation in Polynesian economic systems and their transformations over time; and (4) sociopolitical change, especially as viewed through the lens of household or microscale archaeology. Also noteworthy is the rapidly evolving nature of interactions between archaeologists and native communities, a critical aspect of archaeological practice in the region

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