Browsing by Author "Braga, Érika Martins"

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    Hematological and parasitological health conditions of the Pale-breasted Thrush (Turdus leucomelas) (Passeriformes: Turdidae) in southeastern Brazil.
    (2011) Lobato, Débora Nogueira Campos; Braga, Érika Martins; Belo, Nayara de O.; Antonini, Yasmine
    From an ecological point of view, parasites are considered important selective forces that influence all aspects of a host’s life. The purpose of this study was to assess the health state of Turdus leucomelas Vieillot, 1818 (Turdidae: Passeriformes) inhabiting a Brazilian Cerrado in the breeding and molting seasons through a hematological parameter analysis and an evaluation of infection by blood parasites. The birds were collected with mist-nets, ringed and blood sampled to assess hematological parameters (hematocrit, hemoglobin concentration and white blood cells) and blood parasites. We detected blood parasites through optical microscopy and subsequently used PCR (amplification of the 18sRNA gene) to verify the presence of Plasmodium spp. (avian malaria). During the breeding season, the hemoglobin level and CHGM percentage were greater. Global leukocyte count was positively related to hemoglobin level, CHGM percentage and body weight. Of the total 31 T. leucomelas individuals examined, 18 presented Plasmodium parasites (58% of prevalence). There was a significant relationship between the presence of Plasmodium spp. and decreased CHGM. These results suggest a connection between the health parameters of wild birds and the physiological stress associated with the breeding season.
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    Higher infection probability of haemosporidian parasites in Blue-black Grassquits (Volatinia jacarina) inhabiting native vegetation across Brazil.
    (2021) Fecchio, Alan; Ribeiro, Rayane de Tasso Moreira; Ferreira, Francisco C.; Dutra, Daniela de Angeli; Pascoli, Graziela Virginia Tolesano; Oliveira, Renata Duarte Alquezar de; Khan, Asmat Ullah; Pichorim, Mauro; Moreira, Patrícia de Abreu; Nascimento, Maria de Jesus Costa; Monteiro, Eliana Ferreira; Mathias, Bruno S.; Guimarães, Lilian de Oliveira; Simões, Roseli F.; Braga, Érika Martins; Kirchgatterk, Karin; Dias, Raphael I.
    Human induced changes on landscape can alter the biotic and abiotic factors that influence the transmission of vector-borne parasites. To examine how infection rates of vector-transmitted parasites respond to changes on natural landscapes, we captured 330 Blue-black Grassquits (Volatinia jacarina) in Brazilian biomes and assessed the prevalence and diversity of avian haemosporidian parasites (Plasmodium and Haemoproteus) across avian host populations inhabiting environment under different disturbance and climatic conditions. Overall prevalence in Blue-black Grassquits was low (11%) and infection rates exhibited considerable spatial variation, ranging from zero to 39%. Based on genetic divergence of cytochrome b gene, we found two lineages of Haemoproteus (Parahaemoproteus) and 10 of Plasmodium. We showed that Blue-black Grassquit populations inhabiting sites with higher proportion of native vegetation cover were more infected across Brazil. Other landscape metrics (number of water bodies and distance to urban areas) and climatic condition (temperature and precipitation) known to influence vector activity and promote avian malaria transmission did not explain infection probability in Blue-black Grassquit populations. Moreover, breeding season did not explain prevalence across avian host populations. Our findings suggest that avian haemosporidian prevalence and diversity in Blue-black Grassquit populations are determined by recent anthropogenic changes in vegetation cover that may alter microclimate, thus influencing vector activity and parasite transmission.
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    In vivo antimalarial efficacy of acetogenins, alkaloids and flavonoids enriched fractions from Annona crassiflora Mart.
    (2014) Pimenta, Lúcia Pinheiro Santos; Garcia, Giani Martins; Gonçalves, Samuel Geraldo do Vale; Dionísio, Bárbara Lana; Braga, Érika Martins; Mosqueira, Vanessa Carla Furtado
    Annona crassiflora and Annonaceae plants are known to be used to treat malaria by traditional healers. In this work, the antimalarial efficacy of different fractions of A. crassiflora, particularly acetogenin, alkaloids and flavonoid-rich fractions, was determined in vivo using Plasmodium berghei-infected mice model and toxicity was accessed by brine shrimp assay. The A. crassiflora fractions were administered at doses of 12.5 mg/kg/day in a 4-day test protocol. The results showed that some fractions from woods were rich in acetogenins, alkaloids and terpenes, and other fractions from leaves were rich in alkaloids and flavonoids. The parasitaemia was significantly ( p , 0.05, p , 0.001) reduced (57–75%) with flavonoid and alkaloid-rich leaf fractions, which also increased mean survival time of mice after treatment. Our results confirm the usage of this plant in folk medicine as an antimalarial remedy.
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    Is bigger always better? : neither body size nor aggressive behavior predicts specialization of hummingbirds in a rocky outcrop.
    (2022) Claudino, Ricardo Marcelino; Itabaiana, Yasmine Antonini; Martins, Cristiane; Beirão, Marina do Vale; Braga, Érika Martins; Azevedo, Cristiano Schetini de
    Interspecific competition can strongly influence community structure and shape niche breadth and overlap. One of the main factors that determines hummingbird community structure is competition for food. Hummingbirds’ functional attributes, such as beak length and body mass, influence nectar acquisition in flowers. This study evaluates how functional and behavioral attributes of hummingbirds influence their specialization, as measured by pollen transportation. We tested the following hypothesis: H1) smaller and short-billed hummingbirds will carry higher pollen richness and relatively more pollen grains than long-billed hummingbirds; H2) dominant and territorial hummingbirds carry a lower richness of pollen types and fewer pollen grains when compared to subordinate hummingbirds, and H3) the similarity in the composition of pollen morphotypes, between the hummingbirds species, will be low because we expect to find high specialization in the use of plant species. We conducted the study between September 2018 and March 2019 in a Campo Rupestre (rocky outcrops) in Southeastern Brazil. Hummingbirds were captured with a trap. The pollen adhered to the body parts was collected, counted, and identified in the laboratory. We recorded hummingbirds’ beak sizes and body masses. Behavioral responses of hummingbirds to artificial feeders were collected regarding the time and duration of each visit and the outcome of aggressive inter- actions. An interaction network was built based on the pollen grains found on each hummingbird. Our results showed that neither body size nor aggressive behaviors influenced pollen richness on hummingbirds’ bodies. Beak length was the most important hummingbird attribute that influenced pollen richness, but not pollen relative abundance. Short-billed hummingbirds carried the greatest richness of pollen grains. The hummingbird pollen-grain interaction network was generalized in the pollen grains transported. We conclude that hummingbirds’ beak length is the cen- tral morphological variable related to pollen grain transport in rocky outcrops.
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    Patterns of avian malaria in tropical and temperate environments : testing the “The enemy release hypothesis”.
    (2019) Itabaiana, Yasmine Antonini; Lobato, Débora Nogueira Campos; Norte, Ana Cláudia; Ramos, Jaime Albino; Moreira, Patrícia de Abreu; Braga, Érika Martins
    According to the enemy release hypothesis (ERH) the spread of invasive species will be facilitated by release from their enemies as they occupy new areas. However, the ERH has rarely been tested by comparing populations of native (non-invasive, long established) species with expanding or shifting ranges, to the same species as invasive in another area. We tested the ERH with respect to blood parasite levels (prevalence and intensity of Plasmodium spp. and Haemoproteus spp.) of (a) two closely related, widely distributed species of thrush (Turdus leucomelas and T. merula), and (b) an invasive sparrow (Passer domesticus) whose range has expanded from the Old World to the New World since the 18th century. A total of 158 birds were sampled in Portugal and 99 in Brazil. All bird species were parasitized, and 55% of the individuals collected were parasitized, and the mean intensity of infection was of 28 parasites per 10,000 erythrocytes. We assessed whether differences in levels of infection (prevalence and intensity) were due to site (tropical/New World and temperate/Old World) or host species. The ERH was supported: Passer domesticus and Turdus merula had higher levels of parasitism in the Old World than in the New World. Thus, P. domesticus seems to be benefitting from its “recent” range expansion, compared to T. leucomelas, through ecological release from its native parasites and because the parasites of the recently invaded area seem to be infesting native species instead.
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    Plasmodium berghei NK65 induces cerebral leukocyte recruitment in vivo : an intravital microscopic study.
    (2011) Queiroz, Norinne Lacerda; Lima, Onésia Cristina Oliveira; Carneiro, Cláudia Martins; Vilela, Márcia de Carvalho; Teixeira, Antônio Lúcio; Carvalho, Andréa Teixeira de; Araújo, Márcio Sobreira Silva; Martins Filho, Olindo Assis; Braga, Érika Martins; Tavares, Juliana Carvalho
    Malaria is second only to tuberculosis as the leading cause of morbidity and mortality as a consequence of a single infectious agent. Much of the pathology of malaria arises from the inappropriate or excessive immune response mounted by the host in an attempt to eliminate the parasite. We here report the inflammatory changes observed in the cerebral microvasculature of C57BL/6 and BALB/c mice that had been inoculated with Plasmodium berghei NK65, a lethal strain of rodent malaria. Although no neurological signs were observed in experimentally infected mice, inflammation of the cerebral microvasculature was clearly evident. Histopathological analysis demonstrated that alterations in cerebral tissue were more intense in infected C57Bl/6 mice than in infected BALB/c animals. Intravital microscopic examination of the cerebral microvasculature revealed increased leukocyte rolling and adhesion in pial venules of infected mice compared with non-infected animals. The extravasation of Evans blue dye into the cerebral parenchyma was also elevated in infected mice in comparison with their non-infected counterparts. Additionally, protein levels of TNF-_, MIG/CXCL9, MCP-1/CCL2, MIP-1_/CCL3 and RANTES/CCL5 were up-regulated in brain samples derived from infected C57Bl/6 mice. Taken together, the data reported here illustrate the complex strain-dependent relationships between leukocyte recruitment, blood brain barrier permeability and chemokine production.