Dengue virus (DV) infection is a major problem in public health. It can cause fatal diseases such as Dengue hemorrhagic fever and Dengue shock syndrome. Dendritic cells (DC) are professional APCs required for establishing a primary immune response. Here, we investigated the role of human PBMC-derived DC in DV infection. Using different techniques, including plaque assay, flow cytometry analysis, nested RT-PCR, and confocal microscope and electron microscope examinations, we show that DV can enter cultured human DC and produce virus particles. After entrance, DV could be visualized in cystic vesicles, vacuoles, and the endoplasmic reticulum. The DV-infected DC also showed proliferation and hypertrophy of the endoplasmic reticulum as well as the swollen mitochondria. In addition, the DV-stimulated DC could express maturation markers such as B7-1, B7-2, HLA-DR, CD11b, and CD83. Furthermore, the infection of DC by DV induced production of TNF-α and IFN-α, but not IL-6 and IL-12. Although DC underwent spontaneous apoptosis in the absence of feeding cytokines, this process appeared to be delayed after DV infection. Our observations provide important information in understanding the pathogenesis of DV infection.

Acinetobacter baumannii has emerged as a serious cause of nosocomial infections. Rapid identification of this pathogen is required so that appropriate therapy can be given and outbreaks controlled. This study evaluated a multiplex PCR and an automated ribotyping system for the rapid identification of Acinetobacter baumannii. In total, 22 different reference strains and 138 clinical isolates of Acinetobacter spp., identified by 16S-23S rRNA intergenic spacer (ITS) sequence analysis, were evaluated. All A. baumannii isolates (82 clinical isolates and one reference strain) were identified by the multiplex PCR method (specificity 100%). The sensitivity and specificity of the ribotyping system for identification of A. baumannii were 85.5% (71/83) and 93.5% (72/77), respectively. An additional 100 clinical isolates belonging to the Acinetobacter calcoaceticus-A. baumannii complex were used to compare these two methods for identification of A. baumannii, and this comparison revealed a level of disagreement of 14% (14 isolates). The accuracy of the multiplex PCR was 100%, which was confirmed by sequence analysis of the ITS and recA gene of these isolates. Thus, the multiplex PCR method dramatically increased the efficiency and speed of A. baumannii identification.

No abstract

Direct in vivo evidence for the susceptibility of human neuronal cells to dengue virus has not been reported.In this study, we demonstrated that type 2 dengue (DEN-2) virus infection induced extensive apoptosis in the human neuroblastoma cell line SK-N-SH. Phospholipase A 2 (PLA 2 ) was activated by DEN-2 infection, which led to the generation of arachidonic acid (AA). Inhibition of PLA 2 activity by the PLA 2 inhibitors, AACOCF 3 and ONO-RS-082, diminished DEN-2 virus-induced apoptosis. In contrast, the cyclooxygenase inhibitors aspirin and indomethacin, thought to increase AA accumulation by blocking AA catabolism, enhanced apoptosis. Exogenous AA induced apoptosis in a dose-dependent manner. Superoxide anion, which is thought to be generated through the AA-activated NADPH oxidase, was increased after infection. Pretreatment with superoxide dismutase (SOD) protected cells against DEN-2 virus-induced apoptosis. Furthermore, generation of superoxide anion was blocked by AACOCF 3 . In addition, the transcription factors, NF-B and c-Jun, were found to be activated after DEN-2 virus infection. However, pretreatment of cells with oligodeoxynucleotides containing NF-B, but not c-Jun, binding sites (transcription factor decoy) strongly prevented dengue virusinduced apoptosis. The finding that AACOCF 3 and SOD significantly block activation of NF-B suggests that this activation is derived from the AA-superoxide anion pathway. Our results indicate that DEN-2 virus infection of human neuroblastoma cells triggers an apoptotic pathway through PLA 2 activation to superoxide anion generation and subsequently to NF-B activation. This apoptotic effect can be either directly derived from the action of AA and superoxide anion on mitochondria or indirectly derived from the products of apoptosis-related genes activated by NF-B.Dengue virus, a mosquito-borne human pathogen, is a member of the Flaviviridae and is classified into four serotypes (Dengue virus type 1 through 4, designated here DEN-1, -2, -3, and -4 virus) (27,74). Dengue disease, which is caused by dengue virus infection, is considered a major public health problem in Southeast Asia and Central America (25, 58). As a consequence of increasing travel to areas of endemicity, dengue infection has been imported to many parts of the world. Classic dengue fever generally presents in older children and adults with high fever, severe headache and retro-orbital pain, myalgia, arthralgia, nausea, and rash. The acute phase may last for up to a week, but prolonged recovery is common and is sometimes associated with fatigue and depression. In some cases, hemorrhagic manifestations (dengue hemorrhagic fever) and signs of circulatory failure occur, leading to sudden and often hypovolemic shock (dengue shock syndrome) (26,88). An increasing number of cases have been reported with manifestations of encephalopathy and encephalitis, which cover a wide range of symptoms and signs from headache and clouded sensorium to convulsion, spasticity, and coma (34,49,73,79). As a result, the etiolo...

BackgroundPlasmodium falciparum is the major species responsible for malaria transmission on the island of Príncipe, in the Republic of São Tomé and Príncipe (STP). Indoor residual spraying (IRS) has been intensively deployed on the island, since 2003. Other measures included intermittent preventive therapy (IPT), since 2004, as well as artemisinin-based therapy (ACT) and long-lasting insecticidal nets (LLINs) from 2005. The work was coordinated by the Ministry of Health of STP through their Centro Nacional de Endemias (CNE) and the impact of such an integrated control programme on the prevalence and epidemiology of malaria in Príncipe was evaluated.MethodsThe scaling-up of preventive strategies included IRS, LLINs, IPT for pregnant women, as well as early diagnosis and prompt treatment with ACT. Regular implementation of an island-wide IRS programme was carried out yearly in 2003-2005, and later in 2008. Malaria incidence and prevalence were estimated based on passive case detection and active case detection, respectively. Slide positivity rate (SPR) was used as an indicator of any increase of malaria cases during and after the control programme was initiated.ResultsRegular IRS achieved a coverage of 85-90% for each of the four annual cycles (2003-2005, annually and one spraying in 2008) while usage of LLINs was never superior to 50% from 2006-2009. Coverage of IPT steadily increased from 50% in 2004 to 80% in 2008. Since 2006, over 90% of uncomplicated malaria patients received ACT treatment. Severe malaria cases were hospitalized and treated with quinine. Monthly trends of SPR were constantly over 50% in 2003, but steadily decreased below 10% in 2006. SPR has been below 5% since 2007, but an increase to up to 15% was noted in June 2009 when 16 imported cases were detected. A steep decline by 99% of malaria incidence was observed between 2003 and 2008, with an incidence risk of the population of five per thousand, in 2008. No malaria mortality has been reported since 2005. Species shift from falciparum to non-falciparum malaria was noted after a five-year intensive control programme. Cross-sectional country-wide active surveillances showed malaria prevalences of 1.1%, 0.7%, and 0.9% in June 2006, Oct 2007, and July 2009, respectively, of which over 90% were asymptomatic.ConclusionThe effective measures of the combination of four major control methods have produced a rapid decline in malaria morbidity and mortality on the island of Príncipe. The combination of IRS, IPT, and active surveillance with ACT treatment seemed to have played important roles to achieve a present status of low and stable malaria on the island. In low transmission settings, any increase of malaria morbidity indicates potential epidemics and assumes that current control strategies were interrupted. Active surveillance should be reinforced to follow and monitor all asymptomatic carriers and imported cases. Consolidation and a shift to elimination phase demands the sustainability of such integrated programmes.