Overview of latest articles and publications on ebola in PubMed. PubMed is a service of the US National Library of Medicine that includes over 18 million citations from MEDLINE and other life science journals.
- Incidence of Dengue Virus Infection in Adults and Children in a Prospective Longitudinal Cohort in the Philippines.
Alera MT, Srikiatkhachorn A, Velasco JM, et al. Incidence of Dengue Virus Infection in Adults and Children in a Prospective Longitudinal Cohort in the Philippines. [JOURNAL ARTICLE]PLoS Negl Trop Dis 2016 Feb; 10(2):e0004337.The mean age of dengue has been increasing in some but not all countries. We sought to determine the incidence of dengue virus (DENV) infection in adults and children in a prospective cohort study in the Philippines where dengue is hyperendemic.A prospective cohort of subjects ≥6 months old in Cebu City, Philippines, underwent active community-based surveillance for acute febrile illnesses by weekly contact. Fever history within the prior seven days was evaluated with an acute illness visit followed by 2, 5, and 8-day, and 3-week convalescent visits. Blood was collected at the acute and 3-week visits. Scheduled visits took place at enrolment and 12 months that included blood collections. Acute samples were tested by DENV PCR and acute/convalescent samples by DENV IgM/IgG ELISA to identify symptomatic infections. Enrolment and 12-month samples were tested by DENV hemagglutination inhibition (HAI) assay to identify subclinical infections. Of 1,008 enrolled subjects, 854 completed all study activities at 12 months per-protocol undergoing 868 person-years of surveillance. The incidence of symptomatic and subclinical infections was 1.62 and 7.03 per 100 person-years, respectively. However, in subjects >15 years old, only one symptomatic infection occurred whereas 27 subclinical infections were identified. DENV HAI seroprevalence increased sharply with age with baseline multitypic HAIs associated with fewer symptomatic infections. Using a catalytic model, the historical infection rate among dengue naïve individuals was estimated to be high at 11-22%/year.In this hyperendemic area with high seroprevalence of multitypic DENV HAIs in adults, symptomatic dengue rarely occurred in individuals older than 15 years. Our findings demonstrate that dengue is primarily a pediatric disease in areas with high force of infection. However, the average age of dengue could increase if force of infection decreases over time, as is occurring in some hyperendemic countries such as Thailand.
- Acute Systemic Infection with Dengue Virus Leads to Vascular Leakage and Death through Tumor Necrosis Factor-α and Tie2/Angiopoietin Signaling in Mice Lacking Type I and II Interferon Receptors.
Phanthanawiboon S, Limkittikul K, Sakai Y, et al. Acute Systemic Infection with Dengue Virus Leads to Vascular Leakage and Death through Tumor Necrosis Factor-α and Tie2/Angiopoietin Signaling in Mice Lacking Type I and II Interferon Receptors. [JOURNAL ARTICLE]PLoS One 2016; 11(2):e0148564.Severe dengue is caused by host responses to viral infection, but the pathogenesis remains unknown. This is, in part, due to the lack of suitable animal models. Here, we report a non-mouse-adapted low-passage DENV-3 clinical isolate, DV3P12/08, derived from recently infected patients. DV3P12/08 caused a lethal systemic infection in type I and II IFN receptor KO mice (IFN-α/β/γR KO mice), which have the C57/BL6 background. Infection with DV3P12/08 induced a cytokine storm, resulting in severe vascular leakage (mainly in the liver, kidney and intestine) and organ damage, leading to extensive hemorrhage and rapid death. DV3P12/08 infection triggered the release of large amounts of TNF-α, IL-6, and MCP-1. Treatment with a neutralizing anti-TNF-α antibody (Ab) extended survival and reduced liver damage without affecting virus production. Anti-IL-6 neutralizing Ab partly prolonged mouse survival. The anti-TNF-α Ab suppressed IL-6, MCP-1, and IFN-γ levels, suggesting that the severe response to infection was triggered by TNF-α. High levels of TNF-α mRNA were expressed in the liver and kidneys, but not in the small intestine, of infected mice. Conversely, high levels of IL-6 mRNA were expressed in the intestine. Importantly, treatment with Angiopoietin-1, which is known to stabilize blood vessels, prolonged the survival of DV3P12/08-infected mice. Taken together, the results suggest that an increased level of TNF-α together with concomitant upregulation of Tie2/Angiopoietin signaling have critical roles in severe dengue infection.
- Aedes aegypti anti-salivary gland antibody concentration and dengue virus exposure history in healthy individuals living in an endemic area in Colombia.
Londoño-Rentería B, Cárdenas JC, Giovanni JE, et al. Aedes aegypti anti-salivary gland antibody concentration and dengue virus exposure history in healthy individuals living in an endemic area in Colombia. [JOURNAL ARTICLE]Biomedica 2015 Dec; 35(4):572-581.Mosquito salivary proteins are able to induce an antibody response that reflects the level of human-vector contact. IgG antibodies against dengue virus (DENV-IgG) are indicators of previous exposure. The risk of DENV transmission is not only associated to mosquito or dengue factors, but also to socioeconomic factors that may play an important role in the disease epidemiology.To determine the effect of the presence of Aedes aegypti mosquitos in different stages in households and the history of dengue exposure on vector-human contact determined by the level of anti-salivary protein antibodies in people living in a Colombian endemic area.A pilot study of 58 households and 55 human subjects was conducted in Norte de Santander, Colombia. A questionnaire for socioeconomic factors was administered and houses were examined for the presence of Ae. aegypti specimens in the aquatic stages. The level of DENV-IgG antibodies (DENV-IgG), in addition to IgG and IgM anti- Ae. aegypti salivary gland extract (SGE) antibodies (SGE-IgG, SGE-IgM) were evaluated by ELISA using blood collected in filter paper.We found a significant higher level of SGE-IgG antibodies in subjects living in houses with Ae. aegypti in aquatic stages. We also found a higher concentration of SGE-IgG antibodies in people exposed to DENV, a positive correlation between IgM-SGE and IgG-DENV and a negative correlation with IgG-SGE.Anti-salivary proteins antibodies are consistent with the presence of Ae. aegypti aquatic stages inside houses and DENV-IgG antibodies concentrations.
- Serological evidence of leptospirosis in patients with a clinical suspicion of dengue in the State of Ceará, Brazil.
de Melo Bezerra LF, Fontes RM, Gomes AM, et al. Serological evidence of leptospirosis in patients with a clinical suspicion of dengue in the State of Ceará, Brazil. [JOURNAL ARTICLE]Biomedica 2015 Dec; 35(4):557-562.Dengue and leptospirosis are two febrile illnesses of great clinical and epidemiological importance in Brazil. Their significant degree of symptomatic similarity makes clinical diagnosis difficult.To diagnose leptospirosis differentially in patients with clinically suspected dengue.In this study, 86 patients with clinically suspected dengue underwent virological and serological diagnostic evaluations for dengue (reverse transcriptase polymerase chain reaction, NS1 immunochromatographic test, and NS1 enzyme-linked immunosorbent assay, ELISA), as well as tests to detect immunoglobulin M (IgM; IgM/IgG Rapid Test and IgM ELISA). The same patients were subsequently evaluated for leptospirosis using Rapid Test IgG/IgM (Bioeasy ® ) and Leptospira IgM ELISA (PanBio ® ).Of the 86 patients, 48 (55.8%) had positive results for dengue in at least one of the tests and five (7.35%) showed positive reactions for leptospirosis.During dengue epidemics, this disease may be misdiagnosed as other infections, including leptospirosis, when diagnosis is based on nonspecific clinical and laboratory criteria alone.
- Human C5a Protein Participates in the Mosquito Immune Response Against Dengue Virus.
Londono-Renteria B, Grippin C, Cardenas JC, et al. Human C5a Protein Participates in the Mosquito Immune Response Against Dengue Virus. [JOURNAL ARTICLE]J Med Entomol 2016 Feb 3.Dengue virus (DENV) is transmitted by Aedes spp mosquitoes during a bloodmeal uptake. The bloodmeal consists of host cells, immune factors, and possibly blood-borne pathogens, such as arboviruses. Human cells and immune-related factors, like the complement system, can remain active in the bloodmeal and may be able to interact with pathogens in the mosquito. Previous studies have shown that active complement proteins impact Plasmodium parasite viability in the Anopheles midgut. Thus, we investigated the effects of the human complement on DENV infection in the midgut of Aedes aegypti. Our findings indicate that mosquitoes receiving DENV mixed with normal non-inactivated human serum showed significantly lower viremia than those fed with heat-inactivated serum. This implies that human complement may act to limit DENV infection in the mosquito midgut. In addition, we found that human complement C5a protein was able to directly communicate with mosquito cells, affecting the cell antiviral response against DENV. Our results also show that human C5a protein is able to interact with several membrane-bound mosquito proteins. Together these results suggest an important role of human complement protein in DENV transmission.
- Complete genome of a dengue virus serotype 4 strain from Amazonas, Brazil.
Nascimento VA, Souza VC, Naveca FG Complete genome of a dengue virus serotype 4 strain from Amazonas, Brazil. [JOURNAL ARTICLE]Mem Inst Oswaldo Cruz 2016 Feb 2.Dengue virus (DENV) infections represent a significant concern for public health worldwide, being considered as the most prevalent arthropod-borne virus regarding the number of reported cases. In this study, we report the complete genome sequencing of a DENV serotype 4 isolate, genotype II, obtained in the city of Manaus, directly from the serum sample, applying Ion Torrent sequencing technology. The use of a massive sequencing technology allowed the detection of two variable sites, one in the coding region for the viral envelope protein and the other in the nonstructural 1 coding region within viral populations.
- Dengue and the olympic and paralympic games in Rio 2016: what do athletes, coaches and visitors need to know?
Vancini RL, Dos Santos Andrade M, Vancini-Campanharo CR, et al. Dengue and the olympic and paralympic games in Rio 2016: what do athletes, coaches and visitors need to know? [JOURNAL ARTICLE]J Sports Med Phys Fitness 2016 Feb 2.
- With regard about the case of Dengue, Chikungunya and Zika co-infection in a patient from Colombia.
Faccini-Martínez ÁA, Botero-García CA, Benítez-Baracaldo FC, et al. With regard about the case of Dengue, Chikungunya and Zika co-infection in a patient from Colombia. [LETTER]J Infect Public Health 2016 Jan 30.
- A Comparative Study on Active and Passive Epidemiological Surveillance for Dengue in Five Latin America Countries.
Sarti E, ĹAzou M, Mercado M, et al. A Comparative Study on Active and Passive Epidemiological Surveillance for Dengue in Five Latin America Countries. [JOURNAL ARTICLE]Int J Infect Dis 2016 Jan 30.Dengue is a notifiable infectious disease in many countries, but underreporting of cases to National Epidemiological Surveillance Systems (NESSs) conceals the true extent of the disease burden. We compared the incidence of dengue identified in a cohort study with that reported to the NESSs.A randomized, placebo-controlled study was undertaken in Brazil, Colombia, Honduras, México and Puerto Rico to assess the efficacy of a tetravalent dengue vaccine (CYD-TDV) in children aged 9-16 years. We compared the incidence of dengue in the placebo group with that reported to the NESSs in a similar age group (10-19 years), from June 2011 to April 2014.3,615 suspected dengue cases were identified in the study over 13,527 person-years of observation. Overall incidence of confirmed dengue was 2.9 per 100 person-years (range 1.5 to 4.1 per 100 person-years). In the NESSs combined, over 3.2 million suspected dengue cases were reported during the same period, corresponding to over 1 billion person-years of observation. The incidence of confirmed dengue reported to the NESS in the same locality where the study took place was 0.286 per 100 person-years across Brazil, Colombia and Mexico (range 0.180 to 0.734 per 100 person-years). The incidence of confirmed dengue was 10.0-fold higher in the study than reported to the same localities in the NESSs (range 3.5- to 19.4-fold higher).There is a substantial underreporting of dengue in the NESSs. Understanding the level of underreporting would allow for more accurate estimates of the dengue burden in Latin America.Sanofi Pasteur.
- The Role of the Membrane in the Structure and Biophysical Robustness of the Dengue Virion Envelope.
Reddy T, Sansom MS The Role of the Membrane in the Structure and Biophysical Robustness of the Dengue Virion Envelope. [JOURNAL ARTICLE]Structure 2016 Jan 23.The dengue virion is surrounded by an envelope of membrane proteins surrounding a lipid bilayer. We have combined the cryoelectron microscopy structures of the membrane proteins (PDB: 3J27) with a lipid bilayer whose composition is based on lipidomics data for insect cell membranes, to obtain a near-atomic resolution computational model of the envelope of the dengue virion. A coarse-grained molecular dynamics simulation on the microsecond timescale enables analysis of key biophysical properties of the dengue outer envelope. Properties analyzed include area per lipid values (for a spherical virion with a mixed lipid composition), bilayer thickness, and lipid diffusion coefficients. Despite the absence of cholesterol from the lipid bilayer, the virion exhibits biophysical robustness (slow lipid diffusion alongside stable bilayer thickness, virion diameter, and shape) that matches the cholesterol-rich membrane of influenza A, with similarly anomalous diffusion of lipids. Biophysical robustness of the envelope may confer resilience to environmental perturbations.