Historically, toxins from animal venoms have contributed significantly to the discovery of new drugs, as illustrated by captopril, the first drug developed from an animal toxin approved for human use ......
Ticks attach to and penetrate their hosts' skin and inactivate multiple components of host responses in order to acquire a blood meal. Infestation loads with the cattle tick, Rhipicephalus microplus, ...are heritable: some breeds carry high loads of reproductively successful ticks, whereas in others, few ticks feed and reproduce efficiently.
In order to elucidate the mechanisms that result in the different outcomes of infestations with cattle ticks, we examined global gene expression and inflammation induced by tick bites in skins from one resistant and one susceptible breed of cattle that underwent primary infestations with larvae and nymphs of R. microplus. We also examined the expression profiles of genes encoding secreted tick proteins that mediate parasitism in larvae and nymphs feeding on these breeds.
Functional analyses of differentially expressed genes in the skin suggest that allergic contact-like dermatitis develops with ensuing production of IL-6, CXCL-8 and CCL-2 and is sustained by HMGB1, ISG15 and PKR, leading to expression of pro-inflammatory chemokines and cytokines that recruit granulocytes and T lymphocytes. Importantly, this response is delayed in susceptible hosts. Histopathological analyses of infested skins showed inflammatory reactions surrounding tick cement cones that enable attachment in both breeds, but in genetically tick-resistant bovines they destabilized the cone. The transcription data provided insights into tick-mediated activation of basophils, which have previously been shown to be a key to host resistance in model systems. Skin from tick-susceptible bovines expressed more transcripts encoding enzymes that detoxify tissues. Interestingly, these enzymes also produce volatile odoriferous compounds and, accordingly, skin rubbings from tick-susceptible bovines attracted significantly more tick larvae than rubbings from resistant hosts. Moreover, transcripts encoding secreted modulatory molecules by the tick were significantly more abundant in larval and in nymphal salivary glands from ticks feeding on susceptible bovines.
Compared with tick-susceptible hosts, genes encoding enzymes producing volatile compounds exhibit significantly lower expression in resistant hosts, which may render them less attractive to larvae; resistant hosts expose ticks to an earlier inflammatory response, which in ticks is associated with significantly lower expression of genes encoding salivary proteins that suppress host immunity, inflammation and coagulation.
BACKGROUND: Tick salivary constituents antagonize inflammatory, immune and hemostatic host responses, favoring tick blood feeding and the establishment of tick-borne pathogens in hosts during ...hematophagy. Amblyomma triste, A. cajennense and A. parvum ticks are very important in veterinary and human health because they are vectors of the etiological agents for several diseases. Insights into the tick salivary components involved in blood feeding are essential to understanding vector-pathogen-host interactions, and transcriptional profiling of salivary glands is a powerful tool to do so. Here, we functionally annotated the sialotranscriptomes of these three Amblyomma species, which allowed comparisons between these and other hematophagous arthropod species. METHODS: mRNA from the salivary glands of A. triste, A. cajennense and A. parvum ticks fed on different host species were pyrosequenced on a 454-Roche platform to generate four A. triste (nymphs fed on guinea pigs and females fed on dogs) libraries, one A. cajennense (females fed on rabbits) library and one was A. parvum (females fed on dogs) library. Bioinformatic analyses used in-house programs with a customized pipeline employing standard assembly and alignment algorithms, protein databases and protein servers. RESULTS: Each library yielded an average of 100,000 reads, which were assembled to obtain contigs of coding sequences (CDSs). The sialotranscriptome analyses of A. triste, A. cajennense and A. parvum ticks produced 11,240, 4,604 and 3,796 CDSs, respectively. These CDSs were classified into over 100 distinct protein families with a wide range of putative functions involved in physiological and blood feeding processes and were catalogued in annotated, hyperlinked spreadsheets. We highlighted the putative transcripts encoding saliva components with critical roles during parasitism, such as anticoagulants, immunosuppressants and anti-inflammatory molecules. The salivary content underwent changes in the abundance and repertoire of many transcripts, which depended on the tick and host species. CONCLUSIONS: The annotated sialotranscriptomes described herein richly expand the biological knowledge of these three Amblyomma species. These comprehensive databases will be useful for the characterization of salivary proteins and can be applied to control ticks and tick-borne diseases.
Transcripts similar to those that encode the nonstructural (NS) proteins NS3 and NS5 from flaviviruses were found in a salivary gland (SG) complementary DNA (cDNA) library from the cattle tick ...Rhipicephalus microplus. Tick extracts were cultured with cells to enable the isolation of viruses capable of replicating in cultured invertebrate and vertebrate cells. Deep sequencing of the viral RNA isolated from culture supernatants provided the complete coding sequences for the NS3 and NS5 proteins and their molecular characterisation confirmed similarity with the NS3 and NS5 sequences from other flaviviruses. Despite this similarity, phylogenetic analyses revealed that this potentially novel virus may be a highly divergent member of the genus Flavivirus. Interestingly, we detected the divergent NS3 and NS5 sequences in ticks collected from several dairy farms widely distributed throughout three regions of Brazil. This is the first report of flavivirus-like transcripts in R. microplus ticks. This novel virus is a potential arbovirus because it replicated in arthropod and mammalian cells; furthermore, it was detected in a cDNA library from tick SGs and therefore may be present in tick saliva. It is important to determine whether and by what means this potential virus is transmissible and to monitor the virus as a potential emerging tick-borne zoonotic pathogen.
Objetivo: construir e validar um Quiz de avaliação cognitiva sobre Febre Maculosa, voltado para avaliar o conhecimento de estudantes que moram e/ou frequentam cidades de risco para a doença. Métodos: ...estudo metodológico desenvolvido em três etapas: construção do Quiz; validação de aparência e conteúdo com nove juízes, com análise realizada através do cálculo de Índice de Validade de Conteúdo, com valor de corte 0,80; e validação semântica, seguindo a metodologia DISABKIDS® com 12 alunos de cursos técnicos profissionalizantes, com avaliação dos dados realizada por estatística descritiva, tendo sido utilizado o programa Statistical Package for the Social Sciences. Resultados: o processo de validação foi subdividido em duas etapas: validação de aparência e conteúdo por profissionais das áreas de biologia e educação e validação semântica por alunos de cursos profissionalizantes. O Quiz foi elaborado e aplicado e os resultados mostraram um índice de validade de conteúdo superior a 0,80 para todas as variáveis analisadas. Na validação semântica, o Quiz foi considerado como de fácil compreensão e não houve dificuldade para o preenchimento. Conclusão: o Quiz construído foi validado quanto à aparência, ao conteúdo e à semântica, tendo alcançado concordância satisfatória, o que garante ser um instrumento adequado para o processo de avaliação sobre a temática investigada. Com isso, espera-se contribuir para a difusão de conhecimento acerca da identificação dos fatores de risco e da prevenção da saúde relacionados à Febre Maculosa.
Research has shown that hepatitis B (HBV) and Delta virus (HDV) are a worldwide public health problem. This study aims to estimate the prevalence rates of HBV and HDV infection in five municipalities ...of Maranhão, Northeastern Brazil.
A total sample between 3856 and 4000 individuals. Questionnaires were used to register sociodemographic characteristics and factors associated with transmission. Patients were tested for hepatitis B virus surface antigen (HBsAg), anti-hepatitis B core antigen (anti-HBc), and antibodies against hepatitis Delta virus (anti-HDV). Factors associated with HBV were detected by means of multivariate Poisson regression.
Overall, 3983 subjects were included. Ninety-two of the participants were HBsAg-positive (2.30%, 95% CI 1.80–2.80), and anti-HBc was detected in 1535 (38.50%, 95% CI 37–40). The factors associated with the presence of anti-HBc were: (1) Municipality (P<0.001); Age (P<0.001); School education (P<0.001); Illicit drug use (P=0.001); non-HBV vaccine (P=0.041). Among the HBsAg carriers, eight were anti-HDV-positive (8.69%, 95% CI 2.90–14.40). The most frequent HBV genotype was D4. The only HDV genotype was HDV-8.
HBV exhibited intermediate endemicity in the studied region. Traditional factors were associated with exposure to the virus. The presence of the HDV was confirmed. The most frequent HBV and HDV genotypes were unlike the ones currently described in Brazil.
Rhipicephalus ( Boophilus) species are monoxenous ticks with seasonal distribution in tropical and subtropical regions. For many years, Rhipicephalus micropluswas considered as a single species; ...however, further analysis split these ticks into two distinct species. Because R. microplusand R. australisshare similar attributes, it is hard to discriminate these two species and explain the changes in the classification of these parasites over the past decades. The reappearance of R. australisis an outcome of new research, which has afforded to better characterize these probably cryptic species. Evidence based on morphological features, the lack of conspecificity, microsatellite markers, mitochondrial 12S and 16S ribosomal DNA, and mitochondrial genome supports the re-classification of R. microplusas different species. Therefore, populations of R. microplusfrom Australia, Cambodia, Philippines, Indonesia, New Caledonia, Borneo, New Guinea, Tahiti and parts of Southeast Asia were recently reinstated as R. australis. Moreover, a better knowledge on the speciation between these two species could pave the way to important advances in tick control strategies.
RESUMO: As espécies pertencentes ao gênero Rhipicephalus (Boophilus) são carrapatos monoxenos de distribuição sazonal em regiões tropicais e subtropicais. Por muito anos, duas espécies de carrapatos foram consideradas como Rhipicephalus microplus.Contudo, estudos recentes reclassificaram esse carrapato em duas espécies: R. micropluse R. australis. Em razão de diversas semelhanças entre R. micropluse R. australis,distinguir essas duas espécies torna-se uma tarefa árdua, o que explica as mudanças de classificação dessas espécies nas últimas décadas. O reaparecimento da espécie R. australissurge com novas pesquisas, resultado de uma melhor caracterização dessas prováveis espécies crípticas. Evidências baseadas em análises das características morfológicas, na ausência de co-especificidade, em marcadores de microssatélites, no DNA ribossomal mitocondrial 12S e 16S, assim como no genoma mitocondrial, suportam a re-classificação de R. micropluscomo duas espécies distintas. Nesse sentido, populações de R. microplusda Austrália, Camboja, Nova Caledônia, Bornéo, Filipinas, Nova Guiné, Indonésia e Taiti foram recentemente renomeadas como R. australis. Além disso, um melhor entendimento sobre a especiação e localização dessas duas espécies pode trazer avanços importantes para melhorar as estratégias de controle desses carrapatos.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This study provides evidence supporting the idea that although inflammatory cells migration to the cardiac tissue is necessary to control the growth of
Trypanosoma cruzi, the excessive influx of such ...cells during acute myocarditis may be deleterious to the host. Production of lipid mediators of inflammation like leukotrienes (LTs) along with cytokines and chemokines largely influences the severity of inflammatory injury in response to tissue parasitism.
T. cruzi infection in mice deficient in 5-lipoxygenase (5-LO), the enzyme responsible for the synthesis of LTs and other lipid inflammatory mediators, resulted in transiently increased parasitemia, and improved survival rate compared with WT mice. Myocardia from 5-LO
−/− mice exhibited reduced inflammation, collagen deposition, and migration of CD4
+, CD8
+, and IFN-γ-producer cells compared with WT littermates. Moreover, decreased amounts of TNF-α, IFN-γ, and nitric oxide synthase were found in the hearts of 5-LO
−/− mice. Interestingly, despite of early higher parasitic load, 5-LO
−/− mice survived, and controlled
T. cruzi infection. These results show that efficient parasite clearance is possible in a context of moderate inflammatory response, as occurred in 5-LO
−/− mice, in which reduced myocarditis protects the animals during
T. cruzi infection.
Males of the cattle tick Rhipicephalus microplus produce salivary immunoglobulin-binding proteins and allotypic variations in IgG are associated with tick loads in bovines. These findings indicate ...that antibody responses may be essential to control tick infestations. Infestation loads with cattle ticks are heritable: some breeds carry high loads of reproductively successful ticks, in others, few ticks feed and they reproduce inefficiently. Different patterns of humoral immunity against tick salivary proteins may explain these phenotypes.
We describe the profiles of humoral responses against tick salivary proteins elicited during repeated artificial infestations of bovines of a tick-resistant (Nelore) and a tick-susceptible (Holstein) breed. We measured serum levels of total IgG1, IgG2 and IgE immunoglobulins and of IgG1 and IgG2 antibodies specific for tick salivary proteins. With liquid chromatography followed by mass spectrometry we identified tick salivary proteins that were differentially recognized by serum antibodies from tick-resistant and tick-susceptible bovines in immunoblots of tick salivary proteins separated by two-dimensional electrophoresis.
Baseline levels of total IgG1 and IgG2 were significantly higher in tick-susceptible Holsteins compared with resistant Nelores. Significant increases in levels of total IgG1, but not of IgG2 accompanied successive infestations in both breeds. Resistant Nelores presented with significantly higher levels of salivary-specific antibodies before and at the first challenge with tick larvae; however, by the third challenge, tick-susceptible Holsteins presented with significantly higher levels of IgG1 and IgG2 tick salivary protein-specific antibodies. Importantly, sera from tick-resistant Nelores reacted with 39 tick salivary proteins in immunoblots of salivary proteins separated in two dimensions by electrophoresis versus only 21 spots reacting with sera from tick-susceptible Holsteins.
Levels of tick saliva-specific antibodies were not directly correlated with infestation phenotypes. However, in spite of receiving apparently lower amounts of tick saliva, tick-resistant bovines recognized more tick salivary proteins. These reactive salivary proteins are putatively involved in several functions of parasitism and blood-feeding. Our results indicate that neutralization by host antibodies of tick salivary proteins involved in parasitism is essential to control tick infestations.
To determine the prevalence of intestinal parasites and possible associated factors.
Cross-sectional epidemiological study of 962 children (3-12-years) from an area within the scope of a basic health ...unit in Ribeirão Preto, São Paulo, Brazil. Data were collected by home interviews and three-sample stool analysis and evaluated with the chi-square and Fisher's exact tests (p<0.05).
The prevalence of intestinal parasites was significantly high (57.5%). Giardia lamblia was the most prevalent (50.8%), followed by Ascaris lumbricoides (17.8%), Entamoeba histolytica, Hymenolepis nana, Entamoeba coli and Enterobius vermiculares (5.6-7.3%) and other parasites of lower prevalence, such as Schistosoma japonicum (1%) and Schistosoma mansoni (0.5%). No statistically significant associations were detected between prevalence and the risk factors analyzed.
Since the area presents good conditions of environmental sanitation, health education programs should be implemented that emphasize hygiene procedures for the hands and for food and water to be consumed by the population.
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