The toxicity of Eugenia caryophyllata bud and leaf oil-derived compounds (acetyleugenol, beta-caryophyllene, eugenol, alpha-humulene, and methyl salicylate) and congeners of eugenol (isoeugenol and methyleugenol) against eggs and females of Pediculus capitis was examined using direct contact application and fumigation methods and compared with those of the widely used delta-phenothrin and pyrethrum. In a filter paper diffusion bioassay with female P. capitis, the pediculicidal activity of the Eugenia bud and leaf oils was comparable to those of delta-phenothrin and pyrethrum on the basis of LT(50) values at 0.25 mg/cm(2). At 0.25 mg/cm(2), the compound most toxic to female P. capitis was eugenol followed by methyl salicylate. Acetyleugenol, beta-caryophyllene, alpha-humulene, isoeugenol, and methyleugenol were not effective. Eugenol at 0.25 mg/cm(2) was as potent as delta-phenothrin and pyrethrum but was slightly less effective than the pyrethroids at 0.125 mg/cm(2). Against P. capitis eggs, methyl salicylate and eugenol were highly effective at 0.25 and 1.0 mg/cm(2), respectively, whereas little or no activity at 5 mg/cm(2) was observed with the other test compounds as well as with delta-phenothrin and pyrethrum. In fumigation tests with female P. capitis at 0.25 mg/cm(2), eugenol and methyl salicylate were more effective in closed cups than in open ones, indicating that the effect of the compounds was largely due to action in the vapor phase. Neither delta-phenothrin nor pyrethrum exhibited fumigant toxicity. The Eugenia bud and leaf essential oils, particularly eugenol and methyl salicylate, merit further study as potential P. capitis control agents or lead compounds.

BackgroundJapanese encephalitis virus (JEV) genotype V reemerged in Asia (China) in 2009 after a 57-year hiatus from the continent, thereby emphasizing a need to increase regional surveillance efforts. Genotypic characterization was performed on 19 JEV-positive mosquito pools (18 pools of Culex tritaeniorhynchus and 1 pool of Cx. bitaeniorhynchus) from a total of 64 positive pools collected from geographically different locations throughout the Republic of Korea (ROK) during 2008 and 2010.FindingsTwo regions of the JEV genome were sequenced from 19 pools; the envelope gene and the nonstructural protein 5 (NS5)/3'-untranslated region (UTR). Eighteen pools of Culex tritaeniorhynchus and one pool of Cx. bitaeniorhynchus were positive for genotype I and genotype V, respectively. Sequence alignment of the complete E gene from Cx. bitaeniorhynchus showed high amino acid similarity (98.8%) to the Muar strain, characterized as the first report of genotype V, isolated from an encephalitis patient in Malaysia in 1952.ConclusionThis study represents the first report of JEV genotype V in the ROK. The reemergence of genotype V in Asia (China and ROK) after more than a half-century and its discovery in Cx. bitaeniorhynchus, a mosquito species previously unknown to carry JEV in the ROK, emphasizes the need for enhanced JE surveillance to monitor the dynamics of JEV strains within the region. Future findings may have implications with regard to JEV vaccination/prevention strategies.

Babesia microti causes “emergency” human babesiosis. However, little is known about the alterations in B. microti invaded red blood cells (Bm-RBCs) at the individual cell level. Through quantitative phase imaging techniques based on laser interferometry, we present the simultaneous measurements of structural, chemical, and mechanical modifications in individual mouse Bm-RBCs. 3-D refractive index maps of individual RBCs and in situ parasite vacuoles are imaged, from which total contents and concentration of dry mass are also precisely quantified. In addition, we examine the dynamic membrane fluctuation of Bm-RBCs, which provide information on cell membrane deformability.