Rickettsial infection in Amblyomma nodosum ticks (Acari: Ixodidae) from Brazil

The rickettsial infections in 174 Amblyomma nodosum found on passeriform birds in the Atlantic forest, eastern Brazil, have recently been evaluated. Rickettsiae were successfully isolated from two ticks, using cultures of Vero cells. Both isolates were molecularly characterised, using the rickettsial genes gltA and htrA and, when possible, also ompA and ompB. Portions of the gltA and htrA genes from one of the rickettsial isolates were found be closely match the corresponding GenBank sequences for Rickettsia bellii, with 99.9% and 100% homology, respectively. This isolate was named R. bellii strain Pontal. Portions of the gltA, htrA and ompB genes from the second isolate most closely matched the corresponding sequences of R. parkeri, whereas a portion of the ompA gene from this isolate was closest to the relevant sequence of Rickettsia sp. strain COOPERI (which has been considered to be a strain of R. parkeri in Brazil). The second isolate was named R. parkeri strain NOD. Further investigation of the 172 ticks from which isolates were not recovered revealed R. parkeri strain NOD in 40 and R. bellii strain Pontal in nine, giving overall infection prevalences of 23.6% (41/174) and 5.7% (10/174), respectively. This appears to be the first report of R. bellii and R. parkeri in A. nodosum.

Apoptotic and developmental effects of bovine Herpesvirus type-5 infection on in vitro-produced bovine embryos

Bovine Herpesvirus type-5 (BoHV-5), which is potentially neuropathogenic, was recently described to be related with reproductive disorders in cows. The objective was to elucidate mechanisms involved in propagation of BoHV-5 in embryonic cells. For this purpose, bovine embryos produced in vitro were assayed for apoptotic markers after experimental infection of oocytes, in vitro fertilization, and development. Host DNA fragmentation was detected with a TUNEL assay, expression of annexin-V was measured with indirect immunofluorescence, and viral DNA was detected with in situ hybridization. Infective BoHV-5 virus was recovered from embryos derived from exposed oocytes after two consecutive passages on Madin-Darby bovine kidney (MDBK) cells. The viral DNA corresponding to US9 gene, localized between nucleotides 126243 to 126493, was detected in situ and amplified. There was no significant difference between the ratio of TUNEL stained nuclei and total cells in good quality blastocysts (0.87 +/- 0.05, mean SD), but there were differences (P < 0.05) between infected (0.18 +/- 0.05) and uninfected blastocysts (0.73 +/- 0.07). The Annexin-V label was more intense in uninfected embryos (0.79 +/- 0.04; P < 0.05). The quality of infected and uninfected embryos was considered equal, with no significant effect on embryonic development. In conclusion, we inferred that BoHV-5 infected bovine oocytes, replicated, and suppressed some apoptotic pathways, without significantly affecting embryonic development. (C) 2010 Elsevier Inc. All rights reserved.

Experimental infection of Crested Caracara (Caracara plancus) with Toxoplasma gondu simulating natural conditions

Toxoplasma gondu affects mainly warm-blooded animals including birds Even though previous experimental data indicate that raptors are resistant to clinical infection there is no information regarding the susceptibility of Brazilian birds of prey to T gondii The present study aimed to observe how the crested caracara a common raptor in Brazil Interacts with T gondu, using an experimental model Seven crested caracaras seronegative for T gondu were separated into infected (n = 5) and control groups (n = 2) Birds from the infected group were fed T gondu-Infected Calomys callosus a rodent present in Brazilian savanna and described as highly susceptible to infection by the parasite for three consecutive days while control animals were fed non-Infected rodents All Infected birds produced T gondu-specific IgG antibodies that were firstly detected at day 7 post-Infection with peak production detected between 15 and 30 dpi No significant alterations in clinical and hematological parameters were observed throughout the experimental period and parasites were sparsely found in muscular tissues after the birds were euthanized In conclusion our results demonstrated that crested caracaras are resistant to oral infection with T gondu suggesting that the host-parasite relationship between both species has reached a remarkable equilibrium (C) 2010 Elsevier B V All rights reserved

Physical, epidemiological, and molecular evaluation of infection by Cryptosporidium galli in Passeriformes

Due to the scarcity of information related to the epidemiology of Cryptosporidium infection in passerine birds, this study aimed to determine the periodicity of fecal shedding of Cryptosporidium spp. oocysts, after natural infection, and its clinical signs, mortality, and molecular characterization. Four hundred eighty fecal samples were collected from 40 birds, including 372 samples from 31 adult birds and 108 samples from nine young birds (up to 12 months old), housed in five aviaries, monthly from September 2007 to September 2008, with the exception of April. The birds originated from aviaries in which the following species were raised: great-billed seed-finch (Oryzoborus maximiliani), lesser seed-finch (Oryzoborus angolensis), ultramarine grosbeak (Cyanocompsa brissonii), and rusty-collared seedeater (Sporophila collaris). The samples were preserved in 2.5% potassium dichromate at 4A degrees C until processing. The oocysts were purified by centrifugal flotation in Sheather`s solution, followed by genomic DNA extraction and molecular characterization of oocysts using the nested polymerase chain reaction for amplification of fragments of the 18S subunit of rRNA gene. Intermittent shedding of oocysts was observed by positive amplification for Cryptosporidium spp. in 91 (24.5%) samples of adult birds and 14 (13%) of young birds. The sequencing of the amplified fragments enabled the identification of Cryptosporidium galli. Although all the aviaries had birds positive for C. galli, morbidity or mortality was observed in only one aviary and was associated with concomitant infection with Escherichia coli and Isospora sp.

Evaluation of somatic cell count thresholds to detect subclinical mastitis in Gyr cows

The objectives of this study were (1) to determine the sensitivity (Se) and specificity (Sp) of somatic cell count (SCC) thresholds to identify subclinical mastitis in Gyr cows caused by major and minor pathogens; (2) to study the effects of month of sampling, rear or front mammary quarters, herd, intramammary infection (IMI), and bacterial species on SCC at quarter level; and (3) to describe the prevalence of IMI in Gyr cows in commercial dairy herds. In total, 221 lactating Gyr cows from 3 commercial dairy farms were selected. Milk samples were collected from individual quarters once a month for 1 yr from all lactating cows for SCC and bacteriological analysis. Mammary quarters were considered the experimental units and the SCC results were log(10)-transformed. Four SCC thresholds (100, 200, 300 and 400 x 10(3) cells/mL) were used to determine Se and Sp to identify infected mammary quarters. The overall prevalence of IMI in quarter milk samples of Gyr cows was 49.8%, and the prevalence of minor pathogens was higher (31.9%) than that of major pathogens (17.8%). Quarter samples with microbial isolation presented higher SCC compared with negative samples. Sensitivity and Sp of selected SCC thresholds varied according to the group of pathogen (major and minor) involved in the IMI definition. Sensitivity increased and Sp decreased when mammary quarters with only major pathogens isolation were considered positive. The use of a single SCC analysis to classify quarters as uninfected or infected in Gyr cows may not be a useful test for this breed because Se and Sp of SCC at the studied thresholds were low. The occurrence of IMI and the bacterial species are the main factors responsible for SCC variation in mammary quarters of Gyr cows. Milk samples with major pathogens isolation elicited higher SCC than those with minor pathogens.

Oral manifestations of human T-cell lymphotropic virus infection in adult patients from Brazil

Objective: Human T-cell lymphotropic virus type 1 (HTLV-1) was the first human retrovirus discovered and its pathogenesis is related to T cells infection. This study aimed to verify the presence of oral manifestations in a Brazilian population of patients who was seropositive for HTLV, and identify risk factors for oral manifestations. Subjects and methods: An assessment was made of 139 patients at the Emilio Ribas Institute of Infectious Diseases. Results: A total of 112 (80.5%) patients were HTLV-1, 26 (18.7%) were HTLV-2+. About 35.2% of patients had myelopathy/tropical spastic paraparesis (HAM/TSP), with 48 of them being HTLV-1+ and one patient was seropositive for HTLV-1 and -2. The most common oral manifestations were: xerostomia (26.8%), candidiasis (20.8%), fissured tongue (17.9%), and loss of tongue papillae (10.0%). A multivariate logistic regression analysis showed that HAM/TSP is an independent risk factor for xerostomia (P = 0.02). The patients who were HAM/TSP+ were three times more likely to develop xerostomia when compared with patients without HAM/TSP (odds ratio = 2.69, 95% confidence interval = 1.17-6.17). Conclusion: Despite the fact that the findings of this study suggest a relationship between xerostomia and HAM/TSP, more studies should be developed to show what the association would be between xerostomia presented by HTLV patients and pathogenesis of the virus.

Absence of functional TLR4 impairs response of macrophages after Candida albicans infection

Candida albicans is recognized by phagocytic cells through a set of recognition receptors patterns. Recently, we showed the importance of TLR2 in the regulation of neutrophil survival after C. albicans infection. In the present work, we analyzed the involvement of TLR4 in the recognition of C. albicans by neutrophils and macrophages. Our results show that the absence of functional TLR4 resulted in lower chemotaxis of neutrophils to the site of infection, lower levels of TNF-alpha, CXCL1 and nitric oxide, and dissemination and persistence of the pathogen in lymph nodes and spleen. In vitro, the phagocytic activity, nitric oxide production and myeloperoxidase activity, CXCL1, IL-1 beta production by neutrophils from TLR4-defective mice were not changed. In contrast, macrophages from TLR4-defective mice demonstrated lower phagocytosis and lower levels of CXCL1, IL-1 beta and TNF-alpha. Together, these data demonstrate that TLR4 signals are important for the recognition of C. albicans by macrophages and their absence allows persistence of the infection.

The essential role of toll like receptor-4 in the control of Aggregatibacter actinomycetemcomitans infection in mice

Objective: Aggregatibacter actinomycetemcomitans is an oral Gram-negative bacterium that contributes to periodontitis progression. Isolated antigens from A. actinomycetemcomitans could be activating innate immune cells through Toll-like receptors (TLRs). In this study, we evaluated the role of TLR4 in the control of A. actinomycetemcomitans infection. Material and Methods: We examined the mechanisms that modulate the outcome of A. actinomycetemcomitans-induced periodontal disease in TLR4(-/-) mice. The production of cytokines was evaluated by ELISA. The bacterial load was determined by counting the number of colony-forming units per gram of tissue. Results: The results showed that TLR4-deficient mice developed less severe periodontitis after A. actinomycetemcomitans infection, characterized by significantly lower bone loss and inflammatory cell migration to periodontal tissues. However, the absence of TLR4 facilitated the A. actinomycetemcomitans dissemination. Myeloperoxidase activity was diminished in the periodontal tissue of TLR4(-/-) mice. We observed a significant reduction in the production of tumour necrosis factor-alpha (TNF-alpha) and interleukin (IL)-1 beta in the periodontal tissue of TLR4(-/-) mice. Conclusion: The results of this study highlighted the role of TLR4 in controlling A. actinomycetemcomitans infection.

Absence of TLR2 influences survival of neutrophils after infection with Candida albicans

Candida albicans is an opportunistic pathogen, which causes local and/or disseminated diseases in immunosuppressed humans. Phagocytic cells play a critical role in the immune response against C. albicans. Toll like receptors (TLR) are important in the identification of invading microorganisms and in the regulation of neutrophil survival. TLR2 has been shown to participate in the response against pathogenic yeasts and to increase the functional life span of neutrophils. In view of these observations, we studied the involvement of TLR2 in neutrophil function after C. albicans infection. The absence of TLR2 resulted in lower chemotaxis of neutrophils to the site of infection. This in turn was associated with lower levels of chemokines from neutrophils, facilitating the dissemination of the pathogen to the lymph nodes and spleen. A high frequency of apoptotic neutrophils and macrophages in the inflammatory exudates from TLR2(-/-) mice was found. In addition, the phagocytic activity of neutrophils and macrophages, nitric oxide production and myeloperoxidase, activity were diminished in cells from TLR2(-/-) mice. Together, these data demonstrate the importance of TLR2 signals for neutrophils activation and survival after C albicans infection.

The effects of copper on the microbial community of a coral reef sponge

Marine sponges often harbour communities of symbiotic microorganisms that fulfil necessary functions for the well-being of their hosts. Microbial communities associated with the sponge Rhopaloeides odorabile were used as bioindicators far sublethal cupric ion (Cu2+) stress. A combined strategy incorporating molecular, cultivation and electron microscopy techniques was adopted to monitor changes in microbial diversity. The total density of sponge-associated bacteria and counts of the predominant cultivated symbiont (alpha -proteobacterium strain NW001) were significantly reduced in response to Cu2+ concentrations of 1.7 mug l(-1) and above after 14 days of exposure. The number of operational taxonomic units (OTUs) detected by restriction fragment length polymorphism (RFLP) decreased by 64% in sponges exposed to 223 mug l(-1) Cu2+ for 48 h and by 46% in sponges exposed to 19.4 mug l(-1) Cu2+ for 14 days. Electron microscopy was used to identify 17 predominant bacterial morphotypes, composing 47% of the total observed cells in control sponges. A reduction In the proportion of these morphotypes to 25% of observed cells was evident in sponges exposed to a Cu2+ concentration of 19.4 mug l(-1). Although the abundance of most morphotypes decreased under Cu2+ stress, three morphotypes were not reduced in numbers and a single morphotype actually increased in abundance. Bacterial numbers, as detected using fluorescence in situ hybridization (FISH), decreased significantly after 48 h exposure to 19.4 mug l(-1) Cu2+. Archaea, which are normally prolific in R. odorabile, were not detected after exposure to a Cu2+ concentration of 19.4 mug l(-1) for 14 days, indicating that many of the microorganisms associated with R. odorabile are sensitive to free copper. Sponges exposed to a Cu2+ concentration of 223 mug l(-1) became highly necrosed after 48 h and accumulated 142 +/- 18 mg kg(-1) copper, whereas sponges exposed to 19.4 mug l(-1) Cu2+ accumulated 306 +/- 15 mg kg(-1) copper after 14 days without apoptosis or mortality. Not only do sponges have potential for monitoring elevated concentrations of heavy metals but also examining changes in their microbial symbionts is a novel and sensitive bioindicator for the assessment of pollution on important microbial communities.

Transcriptional response of murine macrophages upon infection with opsonized Paracoccidioides brasiliensis yeast cells

Paracoccidioides brasiliensis is the etiologic agent of the Paracoccidioidomycosis the most common systemic mycosis in Latin America. Little is known about the regulation of genes involved in the innate immune host response to P. brasiliensis. We therefore examined the kinetic profile of gene expression of peritoneal macrophage infected with P. brasiliensis. Total RNA from macrophages at 6, 24 and 48 h was extracted, hybridized onto nylon membranes and analyzed. An increase in the transcription of a number of pro-inflammatory molecules encoding membrane proteins, metalloproteases, involved in adhesion and phagocytosis, are described. We observed also the differential expression of genes whose products may cause apoptotic events induced at 24 h. In addition, considering the simultaneous analyses of differential gene expression for the pathogen reported before by our group, at six hours post infection, we propose a model at molecular level for the P. brasiliensis-macrophage early interaction. In this regard, P. brasiliensis regulates genes specially related to stress and macrophages, at the same time point, up-regulate genes related to inflammation and phagocytosis, probably as an effort to counteract infection by the fungus. (c) 2007 Elsevier Masson SAS. All fights reserved.

Interrelationship between Epstein-Barr virus infection in gastric carcinomas and the expression of apoptosis-associated proteins

Aims: Epstein-Barr virus (EBV) and its associated proteins may be protective against the occurrence of apoptosis that would normally inhibit cancer development and progression. Alternatively, the viral infection may cause altered or mutated expression of oncogenes or tumour suppressor genes that are necessary for tumour development. an action that may also involve apoptosis, In this study, a relationship was sought between occurrence of EBV infection, expression of apoptosis-associated proteins (tumour suppressor gene p53 and oncogenes c-myc and bcl-2) and levels of cell death (apoptosis or necrosis) in 119 cases of gastric carcinoma. Methods and results: The EBV status of the gastric carcinomas (using the EBV-encoded small RNA I (EBER-1) and in-situ hybridization), stage and grade of tumour and sex of patients were compared for bcl-2, p53 and c-myc expression patterns. EBER-1 was detected in approximately 20% of cases studied. There was no significant correlation between levels of cell death in the tumour tissue and EBV status. In the protein analyses, development and progression of gastric carcinoma, with or without EBV infection. was independent of bcl-2 expression. However, in gastric cancers with EBV infection, p53 overexpression was inhibited and c-myc expression was increased in early stage cancers, in comparison with decreased c-myc expression in late stage cancers. Conclusions: The p53 and c-myc expression patterns indicate that EBV-infected gastric carcinomas are less likely to have a natural regression via apoptosis at an early stage and explain, in part, the resistance to treatment of late stage of gastric cancers.

Ross River virus transmission, infection, and disease: a cross-disciplinary review

Ross River virus (RRV) is a fascinating, important arbovirus that is endemic and enzootic in Australia and Papua New Guinea and was epidemic in the South Pacific in 1979 and 1980. Infection with RRV may cause disease in humans, typically presenting as peripheral polyarthralgia or arthritis, sometimes with fever and rash. RRV disease notificatïons in Australia average 5,000 per year. The first well-described outbreak occurred in 1928. During World War II there were more outbreaks, and the name epidemic polyarthritis was applied. During a 1956 outbreak, epidemic polyarthritis was linked serologically to a group A arbovirus (Alphavirus). The virus was subsequently isolated from Aedes vigilax mosquitoes in 1963 and then from epidemic polyarthritis patients. We review the literature on the evolutionary biology of RRV, immune response to infection, pathogenesis, serologic diagnosis, disease manifestations, the extraordinary variety of vertebrate hosts, mosquito vectors, and transmission cycles, antibody prevalence, epidemiology of asymptomatic and symptomatic human infection, infection risks, and public health impact. RRV arthritis is due to joint infection, and treatment is currently based on empirical anti-inflammatory regimens. Further research on pathogenesis may improve understanding of the natural history of this disease and lead to new treatment strategies. The burden of morbidity is considerable, and the virus could spread to other countries. To justify and design preventive programs, we need accurate data on economic costs and better understanding of transmission and behavioral and environmental risks.