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- Creators: Mihaleva, Galina
- Creators: Department of Chemistry and Biochemistry
- Creators: School of Human Evolution and Social Change
Background
In 2015, the Zika arbovirus (ZIKV) began circulating in the Americas, rapidly expanding its global geographic range in explosive outbreaks. Unusual among mosquito-borne diseases, ZIKV has been shown to also be sexually transmitted, although sustained autochthonous transmission due to sexual transmission alone has not been observed, indicating the reproduction number (R0) for sexual transmission alone is less than 1. Critical to the assessment of outbreak risk, estimation of the potential attack rates, and assessment of control measures, are estimates of the basic reproduction number, R0.
Methods
We estimated the R0 of the 2015 ZIKV outbreak in Barranquilla, Colombia, through an analysis of the exponential rise in clinically identified ZIKV cases (n = 359 to the end of November, 2015).
Findings
The rate of exponential rise in cases was ρ = 0.076 days[superscript −1], with 95% CI [0.066,0.087] days[superscript −1]. We used a vector-borne disease model with additional direct transmission to estimate the R0; assuming the R0 of sexual transmission alone is less than 1, we estimated the total R0 = 3.8 [2.4,5.6], and that the fraction of cases due to sexual transmission was 0.23 [0.01,0.47] with 95% confidence.
Interpretation
This is among the first estimates of R0 for a ZIKV outbreak in the Americas, and also among the first quantifications of the relative impact of sexual transmission.
Cell-sediment separation methods can potentially enable determination of the elemental composition of microbial communities by removing the sediment elemental contribution from bulk samples. We demonstrate that a separation method can be applied to determine the composition of prokaryotic cells. The method uses chemical and physical means to extract cells from benthic sediments and mats. Recovery yields were between 5% and 40%, as determined from cell counts. The method conserves cellular element contents to within 30% or better, as assessed by comparing C, N, P, Mg, Al, Ca, Ti, Mn, Fe, Ni, Cu, Zn, and Mo contents in Escherichia coli. Contamination by C, N, and P from chemicals used during the procedure was negligible. Na and K were not conserved, being likely exchanged through the cell membrane as cations during separation. V, Cr, and Co abundances could not be determined due to large (>100%) measurement uncertainties. We applied this method to measure elemental contents in extremophilic communities of Yellowstone National Park hot springs. The method was generally successful at separating cells from sediment, but does not discriminate between cells and detrital biological or noncellular material of similar density. This resulted in Al, Ti, Mn, and Fe contamination, which can be tracked using proxies such as metal:Al ratios. With these caveats, we present the first measurements, to our knowledge, of the elemental abundances of a chemosynthetic community. The communities have C:N ratios typical of aquatic microorganisms, are low in P, and their metal abundances vary between hot springs by orders of magnitude.
The ASU School of Dance presents Undergraduate Projects Showing, October 25-26, with works by undergraduate dance students, performed at Margaret Gisolo Dance Studio.
The ASU School of Dance presents School of Dance LIVE!, September 7-9, with works by dance faculty, performed at Galvin Playhouse.
The ASU School of Dance presents Emerging Artists I, February 9-12, with works by guest artists, dance faculty, and students, performed at Dance Studio Theatre, PEBE 132.
The ASU School of Dance presents Rhythms of Life, November 3-5, with works by guest artists performed at Dance Studio Theatre, PEBE 132.
The ASU School of Dance presents Celebrating the Nagrin Legend, September 16-18, with works by dance faculty and visiting artists, performed at the Galvin Playhouse Theatre.
The ASU School of Dance presents New Danceworks II, January 26-29, with works by dance faculty, graduate students, and visiting artists, performed at the Dance Studio Theatre, PEBE 132.
The ASU School of Dance presents Sharing Unimaginable Worlds: Spring Concert 2006, April 27-30, with works by dance faculty, alumni, graduate, undergraduate, and visiting artists, performed at Galvin Playhouse.