The impact of mass drug administration and long-lasting insecticidal net distribution on Wuchereria bancrofti infection in humans and mosquitoes: an observational study in northern Uganda

BACKGROUND: Lymphatic filariasis (LF) in Uganda is caused by Wuchereria bancrofti and transmitted by anopheline mosquitoes. The mainstay of elimination has been annual mass drug administration (MDA) with ivermectin and albendazole, targeted to endemic districts, but has been sporadic and incomplete in coverage. Vector control could potentially contribute to reducing W. bancrofti transmission, speeding up progress towards elimination. To establish whether the use of long-lasting insecticidal nets (LLINs) can contribute towards reducing transmission of W. bancrofti in a setting with ongoing MDA, a study was conducted in an area of Uganda highly endemic for both LF and malaria. Baseline parasitological and entomological assessments were conducted in 2007, followed by high-coverage LLIN distribution. Net use and entomological surveys were carried out after one year, and final parasitological and entomological evaluations were conducted in 2010. Three rounds of MDA had taken place before the study commenced, with a further three rounds completed during the course of the study. RESULTS: In 2007, rapid mapping indicated 22.3% of schoolchildren were W. bancrofti antigen positive, and a baseline survey during the same year found age-adjusted microfilaraemia prevalence was 3.7% (95% confidence interval (CI): 2.6-5.3%). In 2010, age-adjusted microfilaraemia prevalence had fallen to 0.4%, while antigenaemia rates were 0.2% in children < 5 years and 6.0% in ≥ 5 years. In 2010, universal coverage of mosquito nets in a household was found to be protective against W. bancrofti antigen (odds ratio = 0.44, 95% CI: 0.22-0.89). Prevalence of W. bancrofti larvae in anopheline mosquitoes had decreased significantly between the 2007 and 2010 surveys, but there was an apparent increase in vector densities. CONCLUSION: A marked reduction in W. bancrofti infection and infectivity in humans was observed in the study area, where both MDA and LLINs were used to reduce transmission. The extent to which LLINs contributed to this decline is equivocal, however. Further work investigating the impact of vector control on anopheline-transmitted LF in an endemic area not benefitting from MDA would be valuable to determine the effect of such interventions on their own

Frequency, Etiology, Mortality, Cost, and Prevention of Respiratory Tract Infections&mdash;Prospective, One Center Study

Background: Ventilator-associated pneumonia (VAP) is the most monitored form of respiratory tract infections (RTIs). A small number of epidemiological studies have monitored community-acquired pneumonia (CAP), non-ventilator hospital-acquired pneumonia (NV-HAP) and ventilator-associated tracheobronchitis (VAT) in intensive care units (ICUs). The objective of this study was to assess the frequency, etiology, mortality, and additional costs of RTIs. Methods: One-year prospective RTI surveillance at a 30-bed ICU. The study assessed the rates and microbiological profiles of CAP, VAP, NV-HAP, VAT, and VAP prevention factors, the impact of VAP and NV-HAP on the length of ICU stays, and the additional costs of RTI treatment and mortality. Results: Among 578 patients, RTIs were found in 30%. The CAP, NV-HAP, VAP, and VAT rates/100 admissions were 5.9, 9.0, 8.65, and 6.05, respectively. The VAP incidence density/1000 MV-days was 10.8. The most common pathogen of RTI was Acinetobacter baumannii MDR. ICU stays were extended by VAP and NV-HAP for 17.8 and 3.7 days, respectively, and these RTIs increased the cost of therapy by 13,029 and 2708 EUR per patient, respectively. The mortality rate was higher by 11.55% in patients with VAP than those without device-associated and healthcare-associated infections (p = 0.0861). Conclusions: RTIs are a serious epidemiological problem in patients who are admitted and treated in ICU, as they may affect one-third of patients. Hospital-acquired RTIs extend hospitalization time, increase the cost of treatment, and worsen outcomes

Comparative susceptibility to <it>Plasmodium falciparum </it>of the molecular forms M and S of <it>Anopheles gambiae </it>and <it>Anopheles arabiensis</it>

<p>Abstract</p> <p>Background</p> <p>The different taxa belonging to <it>Anopheles gambiae </it>complex display phenotypic differences that may impact their contribution to malaria transmission. More specifically, their susceptibility to infection, resulting from a co-evolution between parasite and vector, might be different. The aim of this study was to compare the susceptibility of M and S molecular forms of <it>Anopheles gambiae </it>and <it>Anopheles arabiensis </it>to infection by <it>Plasmodium falciparum</it>.</p> <p>Methods</p> <p>F3 progenies of <it>Anopheles gambiae s.l</it>. collected in Senegal were infected, using direct membrane feeding, with <it>P. falciparum </it>gametocyte-containing blood sampled on volunteer patients. The presence of oocysts was determined by light microscopy after 7 days, and the presence of sporozoite by ELISA after 14 days. Mosquito species and molecular forms were identified by PCR.</p> <p>Results</p> <p>The oocyst rate was significantly higher in the molecular S form (79.07%) than in the M form (57.81%, Fisher's exact test p < 0.001) and in <it>Anopheles arabiensis </it>(55.38%, Fisher's exact test vs. S group p < 0.001). Mean ± s.e.m. number of oocyst was greater in the <it>An. gambiae </it>S form (1.72 ± 0.26) than in the <it>An. gambiae </it>M form (0.64 ± 0.04, p < 0.0001) and in the <it>An. arabiensis </it>group (0.58 ± 0.04, vs. S group, p < 0.0001). Sporozoite rate was also higher in the molecular form S (83.52%) than in form M (50.98%, Fisher's exact test p < 0.001) and <it>Anopheles arabiensis </it>50.85%, Fisher's exact test vs. S group p < 0.001).</p> <p>Conclusion</p> <p>Infected in the same experimental conditions, the molecular form S of <it>An. gambiae </it>is more susceptible to infection by <it>P. falciparum </it>than the molecular form M of <it>An</it>. <it>gambiae </it>and <it>An. arabiensis</it>.</p

Coherent production of rho- mesons in charged current antineutrino-neon interactions in BEBC

Coherent production of ρ- mesons in charged current antineutrino interactions on neon nuclei is studied in the BEBC bubble chamber exposed to the CERN SPS wide band beam. The cross section is measured to be (95±25)·10-40 cm2 per neon nucleus, averaged over the beam energy spectrum. The distributions of kinematical variables and the absolute value of the cross section are in agreement with theoretical predictions based on the CVC hypothesis and the vector meson dominance model. © 1987 Springer-Verlag

Measurement of the structure functions F2_{2} and xF3_{3} and comparison with QCD predictions including kinematical and dynamical higher twist effects

The isoscalar nucleon structure functions F2(x, Q2) and xF3(x, Q2) are measured in the range 0<Q2<64 GeV2, 1.7<W2<250 GeV2, x<0.7 using ν and {Mathematical expression} interactions on neon in BEBC. The data are used to evaluate possible higher twist contributions and to determine their impact on the evaluation of the QCD parameter Λ. In contrast to previous analyses reaching to such low W2 values, it is found that a low {Mathematical expression} value in the neighbourhood of 100 MeV describes the data adequately and that the contribution of dynamical higher twist effects is small and negative. © 1987 Springer-Verlag