First evidence of concurrent enzootic and endemic transmission of Ross River virus in the absence of marsupial reservoirs in Fiji

BACKGROUND:Ross River virus (RRV) is a zoonotic alphavirus transmitted by several mosquito species. Until recently, endemic transmission was only considered possible in the presence of marsupial reservoirs. METHODS:We investigated RRV seroprevalence in placental mammals, including horses, cows, goats, pigs, dogs, rats, and mice in Fiji, where there are no marsupials. A total of 302 vertebrate serum samples were collected from 86 households from 10 communities in Western Fiji. FINDINGS:Neutralizing antibodies against RRV were detected in 28 to 100% of sera depending on species, and neutralization was strong even at high dilutions. SIGNIFICANCE:Our results are unlikely to be due to cross reactions; Chikungunya is the only other alphavirus known to be present in the Pacific Islands, but it rarely spills over into non-humans, even during epidemics. Our findings, together with recent report of high RRV seroprevalence in humans, strongly suggest that RRV is circulating in Fiji in the absence of marsupial reservoirs. Considering that all non-human vertebrates present in Fiji are panglobal in distribution, RRV has the potential to further expand its geographic range. Further surveillance and access to diagnostics of RRV is critical for the early detection of emergence and outbreaks.Eri Togami, Narayan Gyawali, Oselyne Ong, Mike Kama, Van-Mai Cao-Lormeau ... Philip Weinsteini ... et al

Toxicity of synthetic and natural compounds on Tetranychus urticae and the predator Phytoseiulus macropilis

The objective of this work was to evaluate the toxicity of synthetic and natural compounds on Tetranychus urticae and the predator Phytoseiulus macropilis. Mortality and growth rates of T. urticae and its predator were evaluated after applications of: abamectin, clofentezine, fenpropathrin, fenpyroximate, propargite, sulfur and spiromesifen, at their recommended concentrations; neem oils (Natuneem and Sempre Verde Killer Neem at 1%); and aqueous extracts at 10% of Dieffenbachia brasiliensis, Annona squamosa, Ruta graveolens, Agave angustifolia, Melia azedarach, Sonchus oleraceus, Mentha spicata x M. suaveolens, Allium cepa, Laurus nobilis, and Eucalyptus saligna. The acute toxicity and the influence of the compounds on the instantaneous growth rate of the mites were carried out in laboratory. Extracts of A. cepa, A. angustifolia, neem oil-based products, spiromesifen, propargite, fenpyroximate, abamectin and fenpropathrin caused mortality higher than 83% on T. urticae. Extract of A. angustifolia, Natuneem and clofentezine did not cause significant mortality rates on P. macropilis. Agave angustifolia and Natuneem did not affect significantly the growth rate of this predator. Propargite, fenpyroximate, abamectin, fenpropathrin, spiromesifen and extract of L. nobilis severely affected P. macropilis population

Potential uses of piperonyl butoxide for controlling the cotton whitefly, Bemisia tabaci (Gennadius)

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN024267 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

The ‘‘Auto-Dissemination’’ Approach A Novel Concept to Fight Aedes albopictus in Urban Areas

The main constraint to the fight against container-breeding mosquito vectors of human arboviruses is the difficulty in targeting the multiplicity of larval sources, mostly represented by small man-made water containers. The aim of this work is to assess the feasibility of the "auto-dissemination" approach, already tested for Aedes aegypti, as a possible alternative to traditional, inefficient control tools, against Ae. albopictus in urban areas. The approach is based on the possibility that wild adult females, exposed to artificial resting sites contaminated with pyriproxyfen, can disseminate this juvenile hormone analogue to larval habitats, thus interfering with adult emergence.We carried out four field experiments in two areas of Rome that are typically highly infested with Ae. albopictus, i.e. the main cemetery and a small green area within a highly urbanised neighbourhood. In each area we used 10 pyriproxyfen "dissemination" stations, 10 "sentinel" sites and 10 covered, control sites. The sentinel and control sites each contained 25 Ae. albopictus larvae. These were monitored for development and adult emergence.When a 5% pyriproxyfen powder was used to contaminate the dissemination sites, we observed significantly higher mortality at the pupal stage in the sentinel sites (50-70%) than in the controls (<2%), showing that pyriproxyfen was transferred by mosquitoes into sentinel sites and that it had a lethal effect.The results support the potential feasibility of the auto-dissemination approach to control Ae. albopictus in urban areas. Further studies will be carried out to optimize the method and provide an effective tool to reduce the biting nuisance caused by this aggressive species and the transmission risk of diseases such as Dengue and Chikungunya. These arboviruses pose an increasing threat in Europe as Ae. albopictus expands its range

The Effect of Unemployment Insurance Sanctions on the Transition Rate from Unemployment to Employment

Sanctions or punitive benefits reductions are increasingly used as a tool to enforce compliance of unemployment insurance claimants with search requirements. This article analyses sanctions using a unique administrative data set of individuals who started collecting unemployment insurance in the Netherlands in 1992. After correction for selectivity in the imposition of sanctions, we find that sanctions substantially raise individual re-employment rates. Copyright 2005 Royal Economic Society.