ika virus (ZIKV) is an arthropod-borne flavivirus related to yellow fever, dengue and West Nile viruses 1. ZIKV was first reported in East Africa in 1947 and expanded from the ancestral enzootic cycle in Africa to Asia several decades ago (Fig. 1). At the beginning of the 21st century, the virus expanded into the South Pacific and the Americas, triggering a pandemic that led to 48 countries reporting active ZIKV transmission by 2017 2. Prior to this expansion, there was little scientific research on this virus 3. In this paper, we review the natural history of ZIKV and the current knowledge about ZIKV vector-borne transmission and the mosquito and vertebrate host species potentially involved worldwide. Furthermore, we discuss the possibility of ZIKV spillback into an enzootic cycle outside Africa and review hypotheses regarding ZIKV recent global emergence and evolution. Finally, we identify research priorities for filling remaining gaps and challenges in our understanding of ZIKV. Zika virus natural history The virus was first isolated from a sentinel rhesus macaque and from Aedes (Stegomyia) africanus mosquitoes in the same Ugandan location. Surveillance efforts identified immune people in at least 25 African countries from 1945 to 2014 (reviewed in ref. 4) and in 7 Asian countries or territories from 1952 to 1997 (Fig. 1). However, many of the serologic tests employed in this surveillance are cross-reactive among flaviviruses, thus these results must be interpreted with caution. Nevertheless, direct detection of ZIKV in countries including Senegal,

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The technical feasibility, mechanisms, and performance of degradation of aqueous diuron (22 mg/L) have been studied at pilot scale in two well-defined photocatalytic systems of special interest because natural UV light can be used: heterogeneous photocatalysis with titanium dioxide and homogeneous photocatalysis by photo-Fenton. Equivalent pilot-scale (made up of Compound Parabolic Collectors (CPCs) specially designed for solar photocatalytic applications) and field conditions used for both allowed adequate comparison of the degree of mineralization and toxicity achieved as well as the transformation products generated en route to mineralization by both systems. Total disappearance of diuron is attained by both phototreatments in 45 min. 100% of chlorine was recovered as chloride, but total recovery of nitrogen as inorganic ions was not attained. 90% of mineralization was reached after 200 min of photocatalytic treatment, but toxicity measured by two different bioassays (Daphnia magna and a Microalga) was reduced to below the threshold (EC50%) in a shorter time. Transformation products evaluated by LC-IT-MS by direct injection of the samples were the same in both cases. The main differences between the two processes were in the amount of transformation products (DPs) generated, not in the DPs detected, which were always the same.

Antifouling biocides used in boat paints were analyzed with a battery of toxicity bioassays to evaluate the toxic effects of these compounds on Vibrio fischeri, Daphnia magna and Selenastrum capricornotum. The antifoulants tested were Irgarol 1051, Kathon 5287, chlorothalonil, diuron, dichlofluanid, 2-thiocyanomethylthiobenzothiazole (TCMTB) and tributyltin (TBT). In most cases, the sensitivity of the organisms towards the toxicants followed the order: S. capricornotum > D. magna > V. fischeri. Toxicity by concentration level had the following order:, the toxicity order of compounds was TBT > Kathon 5287 > chlorothalonil > TCMTB > dichlofluanid > Irgarol 1051 > diuron. For V. fischeri (30 min test), the compound toxicity had the following order: Kathon 5287 > TBT > TCMTB > dichlofluanid > Irgarol 1051 > chlorothalonil.Degradation products of Irgarol 1051 and diuron were also tested. Degradation product of Irgarol 1051 was found to be less toxic to the crustacean and the microalga but more toxic to the bacterium. Degradation products of diuron were less toxic to the microalga in comparison with the bacterium. For mixtures of compound, toxicities were additive in only 33% of the cases and 21% of mixtures were less toxic than expected based on the sum of concentrations of toxicants (antagonistic effect). Synergistic enhancements of toxicity were observed for a majority (46%) of the mixtures.The average reproducibility of the EC 50 and LOEC measurements was 27, 24 and 28%, respectively, in the V. fischeri, S. capricornotum and D. magna bioassays. For single compound, the reproducibility of EC 50 was better than ±20% for a vast majority of the measurements with the V. fischeri system, thus agreeing closely with the reported reproducibility values for this relatively well-known assay.

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