Baixa prevalência de hemoparasitos em aves silvestres no Cerrado do Brasil Central

The objective of this study was to assess the prevalence of blood parasites in wild birds in a Cerrado area in Central Brazil. A total of 508 individuals belonging to 26 species and nine families of the order Passeriformes were captured between April 2005 and March 2006 in five different phytophysiognomic types of Cerrado at the Águas Emendadas Ecological Station, DF, Brazil. Analyses revealed that only 35 individuals (6.9% prevalence) were infected by parasites from the genera Haemoproteus or Plasmodium. Only three families, Emberizidae (9.9%), Tyrannidae (6.8%) and Furnariidae (2.2%), were infected. Six bird species were identified as hosts to Plasmodium or Haemoproteus for the first time. No significant difference for prevalence of parasites was found between the dry and rainy seasons (7.2% and 6.3%, respectively), and prevalence during the reproductive period (7.1%) was similar to that of the non-reproductive period (6.7%). Migratory bird species (3.4%) did not differ from resident bird species (8.3%). The low haemoparasite prevalence found for the Cerrado in the present study is one of the lowest registered for wild bird communities in the Neotropics and around the world. The results confirm patterns observed in previous studies in Brazil and the Neotropics. Key words: Avian malaria, Haemoproteus, Neotropical region, passerine birds, Plasmodium.O objetivo do presente estudo foi determinar a prevalência de hemoparasitos de aves silvestres em uma área de Cerrado do Brasil Central. Para isso foram examinados 508 indivíduos pertencentes a 26 espécies e nove famílias de Passeriformes capturados entre abril de 2005 e março de 2006 em cinco fitofisionomias da Estação Ecológica de Águas Emendadas, DF, Brasil. Apenas 35 indivíduos (6,9%) estavam parasitados pelos gêneros Haemoproteus ou Plasmodium. Apenas três famílias se encontraram parasitadas: Emberizidae (9,9%), Tyrannidae (6,8%) e Furnariidae (2,2%). Seis espécies de aves são descritas pela primeira vez como hospedeiras de Haemoproteus ou Plasmodium. Não foram encontradas diferenças significativas nas prevalências de parasitismo entre as estações seca (7,2%) e chuvosa (6,3%). A prevalência durante a estação reprodutiva foi similar à da estação não reprodutiva. Espécies migratórias não diferiram das espécies residentes na prevalência de infecções por ambos os gêneros de hemoparasitos. A baixa prevalência de hemoparasitos encontrada na área de Cerrado estudada é uma das menores já registrada para comunidades de aves silvestres na região Neotropical e no mundo, confirmando os padrões encontrados em estudos anteriores realizados no Brasil e na região Neotropical. Palavras-chave: Haemoproteus, malária aviária, Passeriformes, Plasmodium, região Neotropical

Baixa prevalência de hemoparasitos em aves silvestres no Cerrado do Brasil Central

The objective of this study was to assess the prevalence of blood parasites in wild birds in a Cerrado area in Central Brazil. A total of 508 individuals belonging to 26 species and nine families of the order Passeriformes were captured between April 2005 and March 2006 in five different phytophysiognomic types of Cerrado at the Águas Emendadas Ecological Station, DF, Brazil. Analyses revealed that only 35 individuals (6.9% prevalence) were infected by parasites from the genera Haemoproteus or Plasmodium. Only three families, Emberizidae (9.9%), Tyrannidae (6.8%) and Furnariidae (2.2%), were infected. Six bird species were identified as hosts to Plasmodium or Haemoproteus for the first time. No significant difference for prevalence of parasites was found between the dry and rainy seasons (7.2% and 6.3%, respectively), and prevalence during the reproductive period (7.1%) was similar to that of the non-reproductive period (6.7%). Migratory bird species (3.4%) did not differ from resident bird species (8.3%). The low haemoparasite prevalence found for the Cerrado in the present study is one of the lowest registered for wild bird communities in the Neotropics and around the world. The results confirm patterns observed in previous studies in Brazil and the Neotropics. Key words: Avian malaria, Haemoproteus, Neotropical region, passerine birds, Plasmodium.O objetivo do presente estudo foi determinar a prevalência de hemoparasitos de aves silvestres em uma área de Cerrado do Brasil Central. Para isso foram examinados 508 indivíduos pertencentes a 26 espécies e nove famílias de Passeriformes capturados entre abril de 2005 e março de 2006 em cinco fitofisionomias da Estação Ecológica de Águas Emendadas, DF, Brasil. Apenas 35 indivíduos (6,9%) estavam parasitados pelos gêneros Haemoproteus ou Plasmodium. Apenas três famílias se encontraram parasitadas: Emberizidae (9,9%), Tyrannidae (6,8%) e Furnariidae (2,2%). Seis espécies de aves são descritas pela primeira vez como hospedeiras de Haemoproteus ou Plasmodium. Não foram encontradas diferenças significativas nas prevalências de parasitismo entre as estações seca (7,2%) e chuvosa (6,3%). A prevalência durante a estação reprodutiva foi similar à da estação não reprodutiva. Espécies migratórias não diferiram das espécies residentes na prevalência de infecções por ambos os gêneros de hemoparasitos. A baixa prevalência de hemoparasitos encontrada na área de Cerrado estudada é uma das menores já registrada para comunidades de aves silvestres na região Neotropical e no mundo, confirmando os padrões encontrados em estudos anteriores realizados no Brasil e na região Neotropical. Palavras-chave: Haemoproteus, malária aviária, Passeriformes, Plasmodium, região Neotropical

Hemoparasitos em passeriformes da Mata Atlântica Brasileira

Parasitos podem levar espécies de aves à extinção, afetar as dinâmicas temporais e espaciais dos hospedeiros, alterar a estrutura de comunidades e o status social de indivíduos. Avaliou-se a prevalência e a intensidade de parasitos em famílias e espécies de 925 aves capturadas, entre 2000 e 2001, na Mata Atlântica de Minas Gerais. Foram coradas com Giemsa extensões de sangue para detectar parasitos hematozoários. As aves (n= 15,8%) 11 famílias estavam infectadas por pelo menos um gênero de parasito, especialmente Muscicapidae (28,3%) e Conopophagidae (25%). Entre as 146 aves infectadas, Plasmodium foi detectado em todas as famílias e possuiu a maior prevalência (54,8%). Trypanosoma,Haemoproteus e microfilaria possuíram baixas prevalências (23,3, 23,3 e 2,1%, respectivamente). Aves capturadasdurante a estação chuvosa estavam mais infectadas do que aves capturadas durante a estação seca. A baixa prevalência geral de parasitos do sangue das aves é semelhante aos padrões encontrados em outras localidades da região Neotropical.Parasites may lead bird species to extinction, affect host temporal and spatial population dynamics, alter community structure and alter individuals social status. We evaluated blood parasite prevalence and intensity according to bird families and species, among 925 birds that were caught in 2000 and 2001, in the Atlantic Forest in the State of Minas Gerais, Brazil. We applied Giemsa staining to thin blood smears, to detect blood parasites. The birds (n = 15.8%) in 11 families, were infected by at least one parasite genus, especially Muscicapidae (28.3%) and Conopophagidae (25%). Among the 146 infected birds, Plasmodium was detected in all bird families and had the highest prevalence (54.8%). Trypanosoma, Haemoproteus and microfilaria had lower prevalence rates (23.3, 23.3 and 2.1%, respectively). Birds caught during the rainy season were more infected than birds caught during the dry season. The overall low prevalence of blood parasites in birds is similar to the patterns found elsewhere in the Neotropical region

Allele-specific antibodies to Plasmodium vivax merozoite surface protein-1: prevalence and inverse relationship to haemoglobin levels during infection.

BACKGROUND: Antigenic polymorphisms are considered as one of the main strategies employed by malaria parasites to escape from the host immune responses after infections. Merozoite surface protein-1 (MSP-1) of Plasmodium vivax, a promising vaccine candidate, is a highly polymorphic protein whose immune recognition is not well understood. METHODS AND RESULTS: The IgG responses to conserved (MSP-119) and polymorphic (block 2 and block 10) epitopes of PvMSP-1 were evaluated in 141 P. vivax infected patients. Ten recombinant proteins corresponding to block 2 (variants BR07, BP29, BP39, BP30, BEL) and block 10 (BR07, BP29, BP39, BP01, BP13) often observed in Brazilian P. vivax isolates were assessed by ELISA in order to determine levels of specific antibodies and their respective seroprevalence. The magnitude and the frequency of variant-specific responses were very low, except for BR07 variant (>40%), which was the predominant haplotype as revealed by block 10 PvMSP-1 gene sequencing. By contrast, 89% of patients had IgG against the C-terminal conserved domain (PvMSP-119), confirming the high antigenicity of this protein. Using multiple linear and logistic regression models, there was evidence for a negative association between levels of haemoglobin and several IgG antibodies against block 2 variant antigens, with the strongest association being observed for BP39 allelic version. This variant was also found to increase the odds of anaemia in these patients. CONCLUSIONS: These findings may have implications for vaccine development and represent an important step towards a better understanding of the polymorphic PvMSP-1 domain as potential targets of vaccine development. These data highlight the importance of extending the study of these polymorphic epitopes of PvMSP-1 to different epidemiological settings

Comparison of the human immune responses to recombinant proteins representing three distinct surface proteins of Plasmodium vivax merozoites

Universidade Federal de São Paulo (UNIFESP), Escola Paulista de Medicina (EPM) Departamento de Microbiologia, Imunologia e ParasitologiaUniversidade Federal do Pará Departamento de PatologiaCenters for Disease Control and Prevention Division of Parasitic DiseasesInstituto Evandro ChagasUniversidade Federal de Minas Gerais Departamento de ParasitologiaUNIFESP, EPM, Depto. de Microbiologia, Imunologia e ParasitologiaSciEL

Correlação entre mediadores inflamatórios e marcadores bioquímicos em pacientes com tuberculose pulmonar ativa

Objective: Correlate inflammatory mediators and biochemical parameters in patients with active pulmonary tuberculosis (TB) treated at a public hospital in São Luís, MA. Methods: This is a case-control study of patients with a positivediagnosis of active pulmonary TB. Serum samples from patients and the control group were collected for the clinical trials, and epidemiological data were collected through medical records and interviews. The control group consisted of healthy volunteers with no previous contact with TB cases, matched by age and sex to the clinical group. To measureinflammatory cytokines, we used the Human IL-6 ELISA Set and Human IFN-γ ELISA Set kits. Oxidative stress was measured by quantification of thiobarbituric acid reactive substances (TBARS) and nitric oxide (NO). In biochemistry, the levels of uric acid, anti-streptolysin “O” (AEO), alanine aminotransferase (ALT), amylase, aspartate aminotransferase (AST), calcium, total cholesterol, gamma-glutamyl transferase (Gamma GT), glucose, alkaline phosphatase, high-density lipoprotein (HDL), C-reactive protein (CRP) and triglycerides were measured. Results: The clinical group consisted of 53 patients. There was a substantial decrease in IFN-γ (p<0.0001) and a significant increase in IL-6 (p<0.0001). TBARS production increased significantly (p= 0.0414). There was no significant difference in NO production (p= 0.3194). In biochemistry, there was a significant increase in ALT (p= 0.0072), AST (p= 0.0016), Gamma GT (p= 0.0011), alkaline phosphatase (p<0.0001), CRP (p<0. .0001) and triglycerides (p= 0.0343), and a significant decrease in calcium (p<0.0001). A significant positive correlation was found between IL-6 and IFN-γ (p= 0.0448), as well as AST and ALT (p<0.0001); CRP and gamma GT (p<0.0001); Gamma GT and ALT (p= 0.0016); Gamma GT and AST (p=0.0004); triglycerides and cholesterol (p= 0.0002); alkaline phosphatase and gamma GT (p<0.0001); CRP and alkaline phosphatase (p<0.0001); triglycerides and calcium (p= 0.0121); cholesterol and calcium (p= 0.0261); glucose and cholesterol (p= 0.0373); and triglycerides and glucose (p= 0.0127) in biochemistry, with a significant negative correlation between glucose and uric acid (p= 0.0092); and CRP and HDL (p=0.0037). The correlation between inflammatory mediators and biochemical markers was positive between IL-6 and gamma GT (p= 0.0011); IL-6 and CRP (p<0.0001); IL-6 and alkaline phosphatase (p=0.0076); and NO and triglycerides (p= 0.0016), and significant negative correlation between IFN-γ and cholesterol (p= 0.0171) and TBARS and cholesterol (p= 0.0138). Conclusion: Immunosuppression of IFN-γ activity was observed. A correlation was found between IL-6 and inflammatory biochemical markers, indicating damage and injury caused by M. tuberculosis.Objetivo: Correlacionar mediadores inflamatórios e parâmetros bioquímicos em pacientes com tuberculose (TB) pulmonar ativa atendidos em um hospital público, em São Luís, MA. Métodos: Trata-se um caso-controle de pacientes com diagnóstico positivo para TB pulmonar ativa. Amostras de soro dos pacientes e grupo controle foram coletadas para os experimentos clínicos e os dados epidemiológicos foram coletados por meio de prontuários e entrevistas. O grupo controle foi formado por voluntários saudáveis sem contato prévio com casos de TB, pareados com idade e sexo ao grupo clínico. Para dosar citocinas inflamatórias, utilizaram-se os kits Human IL-6 ELISA Set e Human IFN-γ ELISA Set. Mediu-se o estresse oxidativo pela quantificação das espécies reativas do ácido tiobarbitúrico (TBARS) e óxido nítrico (ON). Na bioquímica, mediram-se os níveis de ácido úrico, anti-estreptolisina-O (AEO),alanina aminotransferase (ALT), amilase, aspartato aminotransferase (AST), cálcio, colesterol total, gama glutamil transferase (Gama GT), glicose, fosfatase alcalina, lipoproteína de alta densidade (HDL), proteína C reativa (PCR) e triglicerídeos. A análise estatística foi realizada pelo software GraphPad Prism 8, com p<0,05 significativo. Resultados:O grupo clínico foi formado por 53 pacientes. Houve uma diminuição significativa de IFN-γ (p<0,0001),e aumento significativo de IL-6 (p<0,0001). A produção de TBARS aumentou significativamente (p= 0,0414). Não houve diferença significativa na produção de ON (p= 0,3194). Na bioquímica, houve aumento significativo em ALT (p= 0,0072), AST (p= 0,0016), gama GT (p= 0,0011), fosfatase alcalina (p<0,0001), PCR (p<0,0001) e triglicerídeos (p= 0,0343), e diminuição significativa de cálcio (p<0,0001). Encontrou-se correlação positiva significativa entre IL-6 e IFN-γ (p= 0,0448), assim como AST e ALT (p<0,0001); PCR e gama GT (p<0,0001); gama GT e ALT (p= 0,0016); gama GT e AST (p= 0,0004); triglicerídeos e colesterol (p= 0,0002); fosfatase alcalina e gama GT (p<0,0001); PCR e fosfatase alcalina (p<0,0001); triglicerídeos e cálcio (p= 0,0121); colesterol e cálcio (p= 0,0261); glicose e colesterol (p= 0,0373); e triglicerídeos e glicose (p= 0,0127) na bioquímica, sendo negativa significativa entre glicose e ácido úrico (p= 0,0092); e PCR e HDL (p= 0,0037). A correlação entre marcadores inflamatório e bioquímicos foi positiva entre IL-6 e gama GT (p= 0,0011); IL-6 e PCR (p<0,0001); IL-6 e fosfatase alcalina (p= 0,0076); e ON e triglicerídeos (p= 0,0016), e negativa significativa entre IFN-γ e colesterol (p= 0,0171) e TBARS e colesterol (p= 0,0138). Conclusões: Observou-se imunossupressão da atividade de IFN-γ. Encontrou-se correlação entre IL-6 e marcadores bioquímicos inflamatórios, indicando dano e lesão causados por M. tuberculosis

Identification of a Highly Antigenic Linear B Cell Epitope within Plasmodium vivax Apical Membrane Antigen 1 (AMA-1)

Apical membrane antigen 1 (AMA-1) is considered to be a major candidate antigen for a malaria vaccine. Previous immunoepidemiological studies of naturally acquired immunity to Plasmodium vivax AMA-1 (PvAMA-1) have shown a higher prevalence of specific antibodies to domain II (DII) of AMA-1. In the present study, we confirmed that specific antibody responses from naturally infected individuals were highly reactive to both full-length AMA-1 and DII. Also, we demonstrated a strong association between AMA-1 and DII IgG and IgG subclass responses. We analyzed the primary sequence of PvAMA-1 for B cell linear epitopes co-occurring with intrinsically unstructured/disordered regions (IURs). The B cell epitope comprising the amino acid sequence 290–307 of PvAMA-1 (SASDQPTQYEEEMTDYQK), with the highest prediction scores, was identified in domain II and further selected for chemical synthesis and immunological testing. The antigenicity of the synthetic peptide was identified by serological analysis using sera from P. vivax-infected individuals who were knowingly reactive to the PvAMA-1 ectodomain only, domain II only, or reactive to both antigens. Although the synthetic peptide was recognized by all serum samples specific to domain II, serum with reactivity only to the full-length protein presented 58.3% positivity. Moreover, IgG reactivity against PvAMA-1 and domain II after depletion of specific synthetic peptide antibodies was reduced by 18% and 33% (P = 0.0001 for both), respectively. These results suggest that the linear epitope SASDQPTQYEEEMTDYQK is highly antigenic during natural human infections and is an important antigenic region of the domain II of PvAMA-1, suggesting its possible future use in pre-clinical studies

Leucocytozoon cariamae n. sp. and Haemoproteus pulcher coinfection in Cariama cristata (Aves: Cariamiformes): first mitochondrial genome analysis and morphological description of a leucocytozoid in Brazil

The distribution of avian haemosporidians of the genus Leucocytozoon in the Neotropics remains poorly understood. Recent studies confirmed their presence in the region using molecular techniques alone, but evidence for gametocytes and data on putative competent hosts for Leucocytozoon are still lacking outside highland areas. We combined morphological and molecular data to characterize a new Leucocytozoon species infecting a non-migratory red-legged seriema (Cariama cristata), the first report of a competent host for Leucocytozoon in Brazil. Leucocytozoon cariamae n. sp. is distinguished from the Leucocytozoon fringillinarum group by its microgametocytes that are not strongly appressed to the host cell nucleus. The bird studied was coinfected with Haemoproteus pulcher, and we present a Bayesian phylogenetic analysis based on nearly complete mitochondrial genomes of these 2 parasites. Leucocytozoon cariamae n. sp. morphology is consistent with our phylogenetic analysis indicating that it does not share a recent common ancestor with the L. fringillinarum group. Haemoproteus pulcher and Haemoproteus catharti form a monophyletic group with Haemocystidium parasites of Reptilia, supporting the polyphyly of the genus Haemoproteus. We also discussed the hypothesis that H. pulcher and H. catharti may be avian Haemocystidium, highlighting the need to study non-passerine parasites to untangle the systematics of Haemosporida

Outbreak of avian malaria associated to multiple species of plasmodium in magellanic penguins undergoing rehabilitation in Southern Brazil

Avian malaria is a mosquito-borne disease caused by Plasmodium spp. Avian plasmodia are recognized conservationthreatening pathogens due to their potential to cause severe epizootics when introduced to bird populations with which they did not co-evolve. Penguins are considered particularly susceptible, as outbreaks in captive populations will often lead to high morbidity and rapid mortality. We used a multidisciplinary approach to investigate an outbreak of avian malaria in 28 Magellanic penguins (Spheniscus magellanicus) at a rehabilitation center during summer 2009 in Florianópolis, Brazil. Hemosporidian infections were identified by microscopic and molecular characterization in 64% (18/28) of the penguins, including Plasmodium (Haemamoeba) tejerai, Plasmodium (Huffia) elongatum, a Plasmodium (Haemamoeba) sp. Lineage closely related to Plasmodium cathemerium, and a Haemoproteus (Parahaemoproteus) sp. lineage closely related to Haemoproteus syrnii. P. tejerai played a predominant role in the studied outbreak and was identified in 72% (13/18) of the hemosporidian-infected penguins, and in 89% (8/9) of the penguins that died, suggesting that this is a highly pathogenic parasite for penguins; a detailed description of tissue meronts and lesions is provided. Mixed infections were identified in three penguins, and involved P. elongatum and either P. tejerai or P. (Haemamoeba) sp. that were compatible with P. tejerai but could not be confirmed. In total, 32% (9/28) penguins died over the course of 16 days despite oral treatment with chloroquine followed by sulfadiazine-trimethoprim. Hemosporidian infections were considered likely to have occurred during rehabilitation, probably from mosquitoes infected while feeding on local native birds, whereas penguin-mosquitopenguin transmission may have played a role in later stages of the outbreak. Considering the seasonality of the infection, rehabilitation centers would benefit from narrowing their efforts to preventavian malaria outbreaks to the penguins that are maintained throughout summerFAPESP 2009/53956-9, 2010/51801-5FAPEMIGCAPESCNP