Identification of human semiochemicals attractive to the major vectors of onchocerciasis

Background: Entomological indicators are considered key metrics to document the interruption of transmission of Onchocerca volvulus, the etiological agent of human onchocerciasis. Human landing collection is the standard employed for collection of the vectors for this parasite. Recent studies reported the development of traps that have the potential for replacing humans for surveillance of O. volvulus in the vector population. However, the key chemical components of human odor that are attractive to vector black flies have not been identified. Methodology/Principal Findings: Human sweat compounds were analyzed using GC-MS analysis and compounds common to three individuals identified. These common compounds, with others previously identified as attractive to other hematophagous arthropods were evaluated for their ability to stimulate and attract the major onchocerciasis vectors in Africa (Simulium damnosum sensu lato) and Latin America (Simulium ochraceum s. l.) using electroantennography and a Y tube binary choice assay. Medium chain length carboxylic acids and aldehydes were neurostimulatory for S. damnosum s.l. while S. ochraceum s.l. was stimulated by short chain aliphatic alcohols and aldehydes. Both species were attracted to ammonium bicarbonate and acetophenone. The compounds were shown to be attractive to the relevant vector species in field studies, when incorporated into a formulation that permitted a continuous release of the compound over time and used in concert with previously developed trap platforms. Conclusions/Significance: The identification of compounds attractive to the major vectors of O. volvulus will permit the development of optimized traps. Such traps may replace the use of human vector collectors for monitoring the effectiveness of onchocerciasis elimination programs and could find use as a contributing component in an integratedvector control/drug program aimed at eliminating river blindness in Africa

Assessment of safety and quality of fermented milk of camels, cows, and goats sold and consumed in five localities of Burkina Faso

Background and Aim: Fermented milk is food produced and consumed all over the world and plays an important role in human nutrition. This work aimed to evaluate the microbiological and physicochemical quality and mineral composition of fermented milk consumed in Burkina Faso. Materials and Methods: A total of 114 samples of fermented milk from camels, goats, and cows were purchased in the market in five localities in Burkina Faso; Bobo Dioulasso, Djibo, Dori, Gorom-Gorom, and Sebba. Microbiological and physical parameters were monitored using standards methods. Results: Microbiological analysis of fermented milks showed high average values of 7.60±1.50×109 colony-forming unit per milliliter (CFU/ml), 5.72±3.60×107 CFU/ml, 5.53±2.00×105 CFU/ml, 1.97±0.18×103 CFU/ml, 1.98±0.25×103 CFU/ ml, and 0.10±0.09×103 CFU/ml for total microbial flora, lactic acid bacteria, yeasts and molds, Staphylococcus aureus, total coliforms, and thermotolerant coliforms, respectively. None of the samples were contaminated by Salmonella or Shigella. The average values of pH, acidity, dry matter, ash, fats, proteins, and total carbohydrates content of samples were ranged, respectively: 3.830-4.137, 1.888-2.822%, 8.271-13.004%, 0.199-0.476%, 1.210-3.863%, 2.125-3.764%, and 3.080- 5.428 % (w/w). Na/K and Ca/Mg ratio ranged from 0.104 to 0.909 and from 3.392 to 16.996, respectively. Total microbial flora, yeasts and molds, total coliforms, fats, calcium, potassium, iron, and zinc were significantly different. Conclusion: This research contributed in the evaluation of the hygienic and nutritional qualities of local fermented milk. Results obtained in this study confirm the need to set up the training program on the sanitary condition to traditional maker's to ensure the good fermented milk with high organoleptic and nutritional qualities

Field evaluation of baits containing attractive compounds.

<p>Panel A: Collection of <i>Simulium ochraceum s.l.</i> on optimized EWT platforms baited with CO₂ only or CO₂ + selected human odorants (bait). Odorants included in the bait: 1-octen-3-ol, 1-octenol, acetophenone, hexanal, and ammonium bicarbonate. Data were analyzed using a negative binomial regression model and significance determined using a Wald chi square test. In Panel A, *** indicates p<0.0001. Panel B: Collection of <i>Simulium damnosum s.l.</i> on optimized EWT platforms baited with CO₂ only or CO₂ + selected human odorants. Odorants included in the bait: hexanoic acid, heptanoic acid, octanoic acid nonanonic acid, acetophenone, decanal and ammonium bicarbonate. In Panel B, * indicates p<0.01. In each panel, bars indicate the mean collection per trap per day and error bars the standard error of the mean.</p

Identification of human sweat compounds.

<p>Panel A: The overlaid total ion chromatograms from once daily sampling of human armpit sweat of a single Caucasian male over five days. Each sample was run in triplicate; thus 15 traces are visible in the figure. Panel B: Venn diagram of the compounds found to be unique or shared among the three individuals enrolled in the study.</p

Release of attractive compounds from impregnated aroma beads.

<p>Beads were saturated with individual attractive compounds and the release of the absorbed compound measured over 5 days, as described in <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0003450#s2" target="_blank">Materials and Methods</a>. Error bars represent the standard deviation from 3 individual trials.</p