Background: Dengue is a growing problem both in its geographical spread and in its intensity, and yet current global distribution remains highly uncertain. Challenges in diagnosis and diagnostic methods as well as highly variable national health systems mean no single data source can reliably estimate the distribution of this disease. As such, there is a lack of agreement on national dengue status among international health organisations. Here we bring together all available information on dengue occurrence using a novel approach to produce an evidence consensus map of the disease range that highlights nations with an uncertain dengue status. Methods/Principal Findings: A baseline methodology was used to assess a range of evidence for each country. In regions where dengue status was uncertain, additional evidence types were included to either clarify dengue status or confirm that it is unknown at this time. An algorithm was developed that assesses evidence quality and consistency, giving each country an evidence consensus score. Using this approach, we were able to generate a contemporary global map of national-level dengue status that assigns a relative measure of certainty and identifies gaps in the available evidence. Conclusion: The map produced here provides a list of 128 countries for which there is good evidence of dengue occurrence, including 36 countries that have previously been classified as dengue-free by the World Health Organization and/or the US Centers for Disease Control. It also identifies disease surveillance needs, which we list in full. The disease extents and limits determined here using evidence consensus, marks the beginning of a five-year study to advance the mapping of dengue virus transmission and disease risk. Completion of this first step has allowed us to produce a preliminary estimate of population at risk with an upper bound of 3.97 billion people. This figure will be refined in future work.

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Refining the global spatial limits of dengue virus transmission by evidence-based consensus

Gold nanoparticles supported on P25 titania (Au/TiO2) exhibit photocatalytic activity for UV and visible light (532 nm laser or polychromatic light λ > 400 nm) water splitting. The efficiency and operating mechanism are different depending on whether excitation occurs on the titania semiconductor (gold acting as electron buffer and site for gas generation) or on the surface plasmon band of gold (photoinjection of electrons from gold onto the titania conduction band and less oxidizing electron hole potential of about −1.14 V). For the novel visible light photoactivity of Au/TiO2, it has been determined that gold loading, particle size and calcination temperature play a role in the photocatalytic activity, the most active material (ΦH2 = 7.5% and ΦO2 = 5.0% at 560 nm) being the catalyst containing 0.2 wt % gold with 1.87 nm average particle size and calcined at 200 °C.

Influence of excitation wavelength (UV or visible light) on the photocatalytic activity of titania containing gold nanoparticles for the generation of hydrogen or oxygen from water.

This Perspective is focused on the photocatalytic activity of gold nanoparticles supported on titania (Au/TiO2). Titania is the most widely used photocatalyst, but its limited activity under visible light irradiation has motivated the quest for modified titania materials absorbing visible light. The review starts by justifying how doping with metallic elements is a related strategy, but different, to that leading to the use of Au/TiO2 in photocatalysis. Data supporting and confirming the photoactivity of gold nanoparticles in colloidal solutions are briefly presented to justify the possibility of gold photosensitization of titania by electron injection into the conduction band. After describing the most common procedures used to prepare Au/TiO2, the central part of this article is focused on the photocatalytic activity reported for Au/TiO2 for hydrogen generation, dye decoloration, phenol decomposition and carboxylic acid degradation, among other processes. Emphasis is given to the role that parameters like Au loading, particle size, surface area, spatial structuring and others play on the photocatalytic activity. One important issue has been to distinguish those reports using visible light from those other in which direct titania excitation by UV light has been used. These Au/TiO2 photocatalysts can find real applications in the near future for environmental remediation and for hydrogen generation.

Titania supported gold nanoparticles as photocatalyst

HIV testing and counselling is the first crucial step for linkage to HIV treatment and prevention. However, despite high HIV burden in sub-Saharan Africa, testing coverage is low, particularly among young adults and men. Community-based HIV testing and counselling (testing outside of health facilities) has the potential to reduce coverage gaps, but the relative impact of different modalities is not well assessed. We conducted a systematic review of HIV testing modalities, characterizing community (home, mobile, index, key populations, campaign, workplace and self-testing) and facility approaches by population reached, HIV positivity, CD4 count at diagnosis and linkage. Of 2,520 abstracts screened, 126 met eligibility criteria. Community HIV testing and counselling had high coverage and uptake and identified HIV-positive people at higher CD4 counts than facility testing. Mobile HIV testing reached the highest proportion of men of all modalities examined (50%, 95% confidence interval (CI) = 47-54%) and home with self-testing reached the highest proportion of young adults (66%, 95% CI = 65-67%). Few studies evaluated HIV testing for key populations (commercial sex workers and men who have sex with men), but these interventions yielded high HIV positivity (38%, 95% CI = 19-62%) combined with the highest proportion of first-time testers (78%, 95% CI = 63-88%), indicating service gaps. Community testing with facilitated linkage (for example, counsellor follow-up to support linkage) achieved high linkage to care (95%, 95% CI = 87-98%) and antiretroviral initiation (75%, 95% CI = 68-82%). Expanding home and mobile testing, self-testing and outreach to key populations with facilitated linkage can increase the proportion of men, young adults and high-risk individuals linked to HIV treatment and prevention, and decrease HIV burden.

Systematic review and meta-analysis of community and facility-based HIV testing to address linkage to care gaps in sub-Saharan Africa

https://obgyn.onlinelibrary.wiley.com/doi/pdf/10.1111/1471-0528.12629

Pre-eclampsia, eclampsia and adverse maternal and perinatal outcomes: a secondary analysis of the World Health Organization Multicountry Survey on Maternal and Newborn Health

We report on the optical absorption properties of as prepared gold naoparticles of different shapes and sizes measured by photoacoustic (PA) method. The gold nanoparticles of two different shapes (dots, rods) have been prepared using the seed mediated growth method. The shape and the size of these different nanoparticles were determined by STM measurements. PA spectra show the splitting of the surface plasmon resonance (SPR) into two modes (transverse and longitudinal) in case of gold nanorods. The increase in the aspect ratio of the nanorods leads to clear redshifts of the longitudinal SPR. These shifts were used to determine the dielectric constant of the surrounding medium and its variation with the aspect ratios.

http://wiki.phy.queensu.ca/shughes/images/d/dc/Sizeplasmon.pdf

Shape and size dependence of the surface plasmon resonance of gold nanoparticles studied by Photoacoustic technique

Anaemia during pregnancy is major health problem. There is conflicting literature regarding the association between anaemia and its severity and maternal and perinatal outcomes. This is a retrospective case-control study conducted at Kassala hospital, eastern Sudan. Medical files of pregnant women with severe anaemia (haemoglobin (Hb) 11 g/dl, n = 303). Logistic regression analysis was performed separately for each of the outcome measures: preeclampsia, eclampsia, preterm birth, low birth weight (LBW) and stillbirth. There were 9578 deliveries at Kassala hospital, 4012 (41.8%) women had anaemia and 303 (3.2%) had severe anaemia. The corrected risk for preeclampsia increased only in severe anaemia (OR = 3.6, 95% CI: 1.4-9.1, P = 0.007). Compared with women with no anaemia, the risk of LBW was 2.5 times higher in women with mild/moderate anaemia (95% CI: 1.1-5.7), and 8.0 times higher in women with severe anaemia (95% CI: 3.8-16.0). The risk of preterm delivery increased significantly with the severity of anaemia (OR = 3.2 for women with mild/moderate anaemia and OR = 6.6 for women with severe anaemia, compared with women with no anaemia). The corrected risk for stillbirth increased only in severe anaemia (OR = 4.3, 95% CI: 1.9-9.1, P < 0.001). The greater the severity of the anaemia during pregnancy, the greater the risk of preeclampsia, preterm delivery, LBW and stillbirth. Preventive measures should be undertaken to decrease the prevalence of anaemia in pregnancy.

/pdf/severe-anaemia-is-associated-with-a-higher-risk-for-1h4vxduw9l.pdf

Severe anaemia is associated with a higher risk for preeclampsia and poor perinatal outcomes in Kassala hospital, eastern Sudan

There have been few published reports on severe Plasmodium falciparum and Plasmodium vivax malaria among adults in Africa. Clinical pattern/manifestations of severe P. falciparum and P. vivax (according to World Health Organization 2000 criteria) were described in adult patients admitted to Kassala Hospital, eastern Sudan. A total of 139 adult patients (80 males, 57.6%) with a mean (SD) age of 37.2 (1.5) years presented with severe P. falciparum (113, 81.3%) or P. vivax (26, 18.7%) malaria. Manifestations among the 139 patients included hypotension (38, 27.3%), cerebral malaria (23, 16.5%), repeated convulsions (18, 13.0%), hypoglycaemia (15, 10.8%), hyperparasitaemia (14, 10.1%), jaundice (14, 10.1%), severe anaemia (10, 7.2%), bleeding (six, 4.3%), renal impairment (one, 0.7%) and more than one criteria (27, 19.4%). While the geometric mean of the parasite count was significantly higher in patients with severe P. vivax than with severe P. falciparum malaria (5,934.2 vs 13,906.6 asexual stage parasitaemia per μL, p = 0.013), the different disease manifestations were not significantly different between patients with P. falciparum or P. vivax malaria. Three patients (2.2%) died due to severe P. falciparum malaria. One had cerebral malaria, the second had renal impairment, jaundice and hypoglycaemia, and the third had repeated convulsions and hypotension. Severe malaria due to P. falciparum and P. vivax malaria is an existing entity among adults in eastern Sudan. Patients with severe P. falciparum and P. vivax develop similar disease manifestations.

/pdf/severe-plasmodium-falciparum-and-plasmodium-vivax-malaria-ysri5yi87f.pdf

Severe Plasmodium falciparum and Plasmodium vivax malaria among adults at Kassala Hospital, eastern Sudan

Sero-prevalence and factors associated with Helicobacter pylori infection in Eastern Sudan

Eighty-one (71.7%) out of 113 patients had confirmed dengue infection (using ELISA IgM serology) at Kassala, Eastern Sudan during the period of August through November 2010. According to the WHO criteria, dengue fever (DF), dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS) were observed in 30.9, 58, and 11.1% of these patients, respectively. The mean age of these 81 patients was 25.5 years. Male:female ratio was 1.8:1. Various symptoms including fever (100%), headache (75.3%), vomiting (55.6%), nausea (53.1%), and backache (30.9%) were observed among these patients. Thrombocytopenia ( 45) were reported in 86.4, 69.1, and 67.9% of the patients, respectively. High alanine aminotransferase (ALT, >65 U/L) and aspartate aminotransferase (AST >37 U/L) were seen in 9.9 and 14.8% of the patients, respectively. There were five (6.1%) deaths, three of them had DHF and the other two patients had DSS. J. Med. Virol. 84:500–503, 2012. © 2011 Wiley Periodicals, Inc.

/pdf/epidemiology-of-dengue-infections-in-kassala-eastern-sudan-4logobp5h9.pdf

Tajeldin M. Abdallah

Papers

Shape and size dependence of the surface plasmon resonance of gold nanoparticles studied by Photoacoustic technique

Severe anaemia is associated with a higher risk for preeclampsia and poor perinatal outcomes in Kassala hospital, eastern Sudan

Severe Plasmodium falciparum and Plasmodium vivax malaria among adults at Kassala Hospital, eastern Sudan

Sero-prevalence and factors associated with Helicobacter pylori infection in Eastern Sudan

Epidemiology of dengue infections in Kassala, Eastern Sudan.