40 research outputs found
Periodicity in the Quantity and Ratio of Pheromone Components in Volatile Emissions from Virgin Females of the Spotted Stalk Borer Moth Chilo partellus (Swinhoe)
Volatile sex pheromone was collected from the extruded pheromone gland of females of the spotted stalk borer moth Chilo partellus and trapped on glass wool. The pheromone was collected from females on the night of eclosion, 1st, 2nd, 3rd and 5th scotophases thereafter. The female sex pheromone components, (Z)-11-hexadecenal and (Z)-11-hexadecen-1-ol were identified by gas chromatography co-injection with synthetic authentic compounds and confirmed by GC-mass spectrometry. The quantity of the pheromone components was determined by comparison of GC peak areas with that of (E,Z)-3,13-octadecadienyl acetate as an internal standard. Periodicity in the pheromone emission was uni-modal with a peak about the 7-10 h into the scotophase. During the peak period, (Z)-11-hexadecenal was emitted at a rate of 43.1, 30.9, 21.5 and 16.5 ng/30 min on the day of eclosion, 1st, 3rd and 5th scotophases, respectively. A marked reduction in the release rate of the pheromone components was recorded with progressing age of females. This decrease was faster for (Z)-11-hexadecen-I-ol than for (Z)-11-hexadecenal which resulted in a spectacular shift in the ratio (Z)-11-hexadecen-I-ol ranging from about 1:1 at eclosion to 9:1, 22:1 and 32:1 in the 1st, 3rd and 5th scotophases, respectively. The age-dependent shift in both release rate and ratio of pheromone components corresponds to the change in attractiveness of females to mate-searching males. The periodicity in the quantity and blend ratios of C. partellus pheromone is discussed in light of development of a pheromone-based bait for the management of this pest.
Key words: Periodicity, Lepidoptera, Pyralidae, Chilo partellus, sex pheromone, pheromone
East and Central African Journal of Pharmaceutical Sciences Vol.6(2) 2003: 36-4
Bacterial diversity in the intestinal tract of the funguscultivating termite Macrotermes michaelseni (Sjöstedt)
Microorganisms in the intestinal tracts of termites play a crucial role in the nutritional physiology of termites. The bacterial diversity in the fungus-cultivating Macrotermes michaelseni was examined usingboth molecular and culture dependent methods. Total DNA was extracted from the gut of the termite and 16S rRNA genes were amplified using bacterial specific primers. Representatives from forty-one (41) RFLP patterns from a total of one hundred and two (102) clones were sequenced. Most of the clones were affiliated with 3 main groups of the domain Bacteria: Cytophaga-Flexibacter-Bacteriodes(73), Proteobacteria (13), and the low G+C content Gram-positive bacteria (9). Two RFLPs related to planctomycetes, but deeper branching than known members of the phylum, were detected. In addition, 1 and 2 RFLPs represented the spirochetes and TM7-OP11 groups, respectively. In studies using culture dependent techniques, most of the isolates obtained belonged to the Gram-positive bacteriawith a high G+C content. However, only one of the clones represented Gram-positive bacteria with High G+C content. These results show a high bacterial diversity in the intestinal microbiota of M. michaelseni, which continues to escape cultivation. As is the case in other termites many of the clones represent previously uncultured bacteria. The fact that most of the clones clustered with clones from Macrotermes gilvus provides further support for the hypothesis that microorganisms in intestinal tracts of termites have co-evolved with their hosts
Distribution and abundance of key vectors of Rift Valley fever and other arboviruses in two ecologically distinct counties in Kenya
Background
Rift Valley fever (RVF) is a mosquito-borne viral zoonosis of ruminants and humans that causes outbreaks in Africa and the Arabian Peninsula with significant public health and economic consequences. Humans become infected through mosquito bites and contact with infected livestock. The virus is maintained between outbreaks through vertically infected eggs of the primary vectors of Aedes species which emerge following rains with extensive flooding. Infected female mosquitoes initiate transmission among nearby animals, which amplifies virus, thereby infecting more mosquitoes and moving the virus beyond the initial point of emergence. With each successive outbreak, RVF has been found to expand its geographic distribution to new areas, possibly driven by available vectors. The aim of the present study was to determine if RVF virus (RVFV) transmission risk in two different ecological zones in Kenya could be assessed by looking at the species composition, abundance and distribution of key primary and secondary vector species and the level of virus activity.
Methodology
Mosquitoes were trapped during short and long rainy seasons in 2014 and 2015 using CO2 baited CDC light traps in two counties which differ in RVF epidemic risk levels(high risk Tana-River and low risk Isiolo),cryo-preserved in liquid nitrogen, transported to the laboratory, and identified to species. Mosquito pools were analyzed for virus infection using cell culture screening and molecular analysis.
Findings
Over 69,000 mosquitoes were sampled and identified as 40 different species belonging to 6 genera (Aedes, Anopheles, Mansonia, Culex, Aedeomyia, Coquillettidia). The presence and abundance of Aedes mcintoshi and Aedes ochraceus, the primary mosquito vectors associated with RVFV transmission in outbreaks, varied significantly between Tana-River and Isiolo. Ae. mcintoshi was abundant in Tana-River and Isiolo but notably, Aedes ochraceus found in relatively high numbers in Tana-River (n = 1,290), was totally absent in all Isiolo sites. Fourteen virus isolates including Sindbis, Bunyamwera, and West Nile fever viruses were isolated mostly from Ae. mcintoshi sampled in Tana-River. RVFV was not detected in any of the mosquitoes.
Conclusion
This study presents the geographic distribution and abundance of arbovirus vectors in two Kenyan counties, which may assist with risk assessment for mosquito borne diseases
The costâeffectiveness of prophylaxis strategies for individuals with advanced HIV starting treatment in Africa
Introduction Many HIVâpositive individuals in Africa have advanced disease when initiating antiretroviral therapy (ART) so have high risks of opportunistic infections and death. The REALITY trial found that an enhancedâprophylaxis package including fluconazole reduced mortality by 27% in individuals starting ART with CD4 <100 cells/mm3. We investigated the costâeffectiveness of this enhancedâprophylaxis package versus other strategies, including using cryptococcal antigen (CrAg) testing, in individuals with CD4 <200 cells/mm3 or <100 cells/mm3 at ART initiation and all individuals regardless of CD4 count. Methods The REALITY trial enrolled from June 2013 to April 2015. A decisionâanalytic model was developed to estimate the costâeffectiveness of six management strategies in individuals initiating ART in the REALITY trial countries. Strategies included standardâprophylaxis, enhancedâprophylaxis, standardâprophylaxis with fluconazole; and three CrAg testing strategies, the first stratifying individuals to enhancedâprophylaxis (CrAgâpositive) or standardâprophylaxis (CrAgânegative), the second to enhancedâprophylaxis (CrAgâpositive) or enhancedâprophylaxis without fluconazole (CrAgânegative) and the third to standardâprophylaxis with fluconazole (CrAgâpositive) or without fluconazole (CrAgânegative). The model estimated costs, lifeâyears and qualityâadjusted lifeâyears (QALY) over 48 weeks using three competing mortality risks: cryptococcal meningitis; tuberculosis, serious bacterial infection or other known cause; and unknown cause. Results Enhancedâprophylaxis was costâeffective at costâeffectiveness thresholds of US500 per QALY with an incremental costâeffectiveness ratio (ICER) of US113 per QALY in the CD4 <100 cells/mm3 population) and increased in all individuals regardless of CD4 count (US2.30. Conclusions The REALITY enhancedâprophylaxis package in individuals with advanced HIV starting ART reduces morbidity and mortality, is practical to administer and is costâeffective. Efforts should continue to ensure that components are accessed at lowest available prices
Late Presentation With HIV in Africa: Phenotypes, Risk, and Risk Stratification in the REALITY Trial.
This article has been accepted for publication in Clinical Infectious Diseases Published by Oxford University PressBackground: Severely immunocompromised human immunodeficiency virus (HIV)-infected individuals have high mortality shortly after starting antiretroviral therapy (ART). We investigated predictors of early mortality and "late presenter" phenotypes. Methods: The Reduction of EArly MortaLITY (REALITY) trial enrolled ART-naive adults and children â„5 years of age with CD4 counts .1). Results: Among 1711 included participants, 203 (12%) died. Mortality was independently higher with older age; lower CD4 count, albumin, hemoglobin, and grip strength; presence of World Health Organization stage 3/4 weight loss, fever, or vomiting; and problems with mobility or self-care at baseline (all P < .04). Receiving enhanced antimicrobial prophylaxis independently reduced mortality (P = .02). Of five late-presenter phenotypes, Group 1 (n = 355) had highest mortality (25%; median CD4 count, 28 cells/”L), with high symptom burden, weight loss, poor mobility, and low albumin and hemoglobin. Group 2 (n = 394; 11% mortality; 43 cells/”L) also had weight loss, with high white cell, platelet, and neutrophil counts suggesting underlying inflammation/infection. Group 3 (n = 218; 10% mortality) had low CD4 counts (27 cells/”L), but low symptom burden and maintained fat mass. The remaining groups had 4%-6% mortality. Conclusions: Clinical and laboratory features identified groups with highest mortality following ART initiation. A screening tool could identify patients with low CD4 counts for prioritizing same-day ART initiation, enhanced prophylaxis, and intensive follow-up. Clinical Trials Registration: ISRCTN43622374.REALITY was funded by the Joint Global Health Trials Scheme (JGHTS) of the UK Department for International Development, the Wellcome Trust, and Medical Research Council (MRC) (grant number G1100693). Additional funding support was provided by the PENTA Foundation and core support to the MRC Clinical Trials Unit at University College London (grant numbers MC_UU_12023/23 and MC_UU_12023/26). Cipla Ltd, Gilead Sciences, ViiV Healthcare/GlaxoSmithKline, and Merck Sharp & Dohme donated drugs for REALITY, and ready-to-use supplementary food was purchased from Valid International. A. J. P. is funded by the Wellcome Trust (grant number 108065/Z/15/Z). J. A. B. is funded by the JGHTS (grant number MR/M007367/1). The Malawi-LiverpoolâWellcome Trust Clinical Research Programme, University of Malawi College of Medicine (grant number 101113/Z/13/Z) and the Kenya Medical Research Institute (KEMRI)/Wellcome Trust Research Programme, Kilifi (grant number 203077/Z/16/Z) are supported by strategic awards from the Wellcome Trust, United Kingdom. Permission to publish was granted by the Director of KEMRI. This supplement was supported by funds from the Bill & Melinda Gates Foundation