Medically significant indoor/ectoparasitic insect populations, including bed bugs and head lice, have developed considerable resistance to insecticides due to limited introduction of new genetic traits and the absence of an overwintering barrier. In contrast, outdoor pests like Anopheles and Culex mosquitoes exhibit fluctuating resistance patterns, likely influenced by factors such as overwintering barriers and relatively wider open habitats. Mosquitoes also face selection pressure from diverse sources beyond public health insecticides unlike bed bugs or head lice. Understanding different factors driving resistance among pests is essential for effective resistance management.

Bangladeshi medicinal plants (BMP) have a history of traditional use in treating chronic inflammatory diseases, but a BMP bark’s antioxidant and anti-inflammatory effects remain largely unexplored. This study assessed methanolic extracts’ antioxidant and anti-inflammatory properties from the bark of 15 medicinal plant species native to Bangladesh. The methanol extracts of BMP bark were evaluated for their total antioxidant activity and ability to counteract inflammation induced by lipopolysaccharide (LPS) in RAW 264.7 macrophages. Among the 15 bark extracts from BMP, Albizia odoratissima (A. odoratissima), Engelhardia spicata (E. spicata), and Shorea robusta (S. robusta) showed the highest total phenolic contents and total antioxidant capacity by effectively scavenging free radicals. In particular, these three bark extracts significantly reduced the mRNA expression of LPS-induced inflammatory cytokines and enzymes inducible by inflammation in macrophages. Also, the mRNA expression of NADPH oxidase 2 was significantly suppressed by the three bark extracts in LPS-induced RAW 264.7 macrophages. These results suggest that out of the 15 bark extracts obtained from medicinal plants in Bangladesh, the extracts from A. odoratissima, E. spicata, and S. robusta exhibit substantial total antioxidant capacity by efficiently scavenging free radicals and also inhibit LPS-induced inflammation in macrophages.

This study was to evaluate the skin sensitization of potassium hydroxide (KOH) by the guinea pig maximization test. In the preliminary test, the induction and challenge dose of KOH were determined as 1.0 and 0.2%, respectively. Guinea pigs were sensitized with intradermal injection of 0.1ml KOH for 24 h. After 1 week, 1.0% of KOH was treated on the site of injection and 0.2% of KOH was challenged 2 weeks later. The average skin reaction evaluated by erythema and edema on the challenge sites and sensitization rate in the KOH-treatment group at 24 h were 0.0 and 0%, respectively, which are substantially low compared with in the 2,4-dinitrochlorobenzene-treatment group (positive control group) (average skin reaction: 3.0, sensitization rate: 100%) and identical with in the distilled water-treatment group (negative control group), representing a weak sensitizing potential. The average skin reaction and sensitization rate observed at 48 h were 0.0 and 0% in the KOH-treatment group, respectively, and 2.0 and 100% in the positive control group, respectively. It was concluded that 1.0% of KOH classified to Grade I, induced no sensitization when tested in guinea pigs.

Despite the various effects on the health of Chamaecyparis obtusa essential oil (COEO), an adverse effect on the skin has recently been reported. Therefore, in this study, the skin sensitization test of COEO was conducted to confirm the skin safety of the essential oil by the guinea pig maximization test. Guinea pigs were sensitized with intradermal injection of 0.1ml COEO for 24 h. After 1 week, 5% of COEO was treated on the site of injection and 2% of the essential oil was challenged 2 weeks later. The average skin reaction evaluated by erythema and edema on the challenge sites and sensitization rate in the COEO-treatment group at 24 h were 0.0 and 0%, respectively, which are substantially low compared with in the 2,4-dinitrochlorobenzene-treatment group (positive control group) (average skin reaction: 3.0, sensitization rate: 100%) and identical with in the olive oil-treatment group (negative control group), representing a weak sensitizing potential. The average skin reaction and sensitization rate observed at 48 h were 0.0 and 0% in the COEO-treatment group, respectively, and 2.0 and 100% in the positive control group, respectively. It was concluded that 5% of COEO classified to Grade I, induced no sensitization when tested in guinea pigs.

Mosquitoes are primary medical insect pests due to their diseases transmission as vectors. In Korea, the insecticide-resistant populations of disease vector mosquito species, such as Anopheles sinensis, Culex pipiens and Culex tritaeniorhynchus, have constantly increased. Thus, management of insecticide resistance to major insecticides including pyrethroids and organophosphates is required for more efficient control of resistant populations. In this study, the quantitative sequencing (QS) protocols were established to detect the frequencies of three mutations (the L1014F on voltage sensitive sodium channel and the G119S and F331W on acetylcholinesterase 1) that are associated with either pyrethroids or organophosphates. Based on the QS protocol using newly designed non-polymorphic primers, resistance allele frequencies (RAFs) were estimated in field populations of An. sinensis, Cx. pipiens and Cx tritaeniorhynchus collected from an identical site in Korea. The dynamics of each resistance allele frequency over time in the same populations were also evaluated.

Some of the deicer ingredients are the same as fertilizer ingredients from agricultural activities. The goal of this study is to distinguish the components of highway deicer from the components used for agriculture. Among the deicer ingredients, Ca and Cl are substances which can be supplied by fertilizer or livestock manure. However, fertilizer and livestock manure contain plenty of nitrogen, organic matter, phosphoric acid and magnesium, including deicer ingredients. The soil physico-chemical characteristics were analyzed according to the distance from the highway. The physico-chemical analysis items of the soil include electrical conductivity, total nitrogen (TN), available phosphate (Av.P), organic matter (OM), ammonia nitrogen (NH4-N), Cation Exchange Capacity (CEC). In the case of effective phosphoric acid, leaching into the subsoil is very low due to various binding mechanisms in the soil. However, it is considered that the compost (fertilizer) applied to the topsoil is mixed with the soil by the tillage or flattening operation. In addition to the organic matter content of the subsoil appear to 10% or more is that in some cases exhibit a similar level as the topsoil. The average soil organic matter content of about 2.6%. This results shows that an excess of organic compost in the study area flows into subsoil and was mixed with the subsoil. The high EC value at the points outside the snow removal effect range level is not considered to be affected by the deicer. The results of the survey showed that the values were differently detected by agricultural activities, and that they should be approached in a complex way in their interpretation.

Human body and head lice are obligatory human ectoparasites. Although both body and head lice belong to a single species, Pediculus humanus, only body lice are known to be a vector of several bacterial diseases. The higher vector competence of body lice is assumed to be due to their weaker immune response than that of head lice. To test this hypothesis, immune reactions were compared between body and head lice following infections by two model bacteria, Staphylococcus aureus and Escherichia coli, and a human pathogen, Bartonella quintana. Following dermal or oral challenge, the number of these bacteria increased both in hemocoel and alimentary tract of body lice but not in head lice and the viability of the B. quintana was significantly higher in body louse feces, the major route of infection to human. In addition, body lice showed the lower basal/induced transcription level of major immune genes, cytotoxic reactive oxygen species and phagocytosis activity compared with head lice. These findings suggest that a reduced immune response may be responsible, in part, for the increased proliferation and excretion of viable bacteria which are associated with the high level of human infectivity seen in body versus head lice.

Leptotrombidium pallidum is the major vector mites for Orientia tsutsugamushi, the causative agent of scrub typhus. To understand the molecular mechanism of L. pallidum, we sequenced the whole genome using Illumina sequencing technology. Totally four genomic libraries with different insert sizes ranging from 280 bp to 8 kb were used to generate 45.1 Gb of genome in the combination of paired-end and mate-pairs sequencing reads. Quality filtering and correction of paired-end reads for very small and/or bad-quality sequences yielded 26.9 Gb of high-quality sequences, which are used to estimate the genome size as 175 Mbusing kmer methods and assembled into a 193.7 Mb genomic sequence scaffolds with N50 length of 92,945 bp. Furthermore, 94% of CEGMA completeness score were obtained from genome scaffold assembly. To facilitate gene annotation, we used a combination of de novo and homology based tools to predict gene models in the chigger mite genome. A combination of evidence-based and de novo approaches predicted 15,842 high-confidence protein-coding genes with an average transcript length of 1,511 bp and 2.4 exons per gene which corresponds to about 12.4% total gene length. Bacterial endosymbiosis are very common in mite species and can range from mutualistic to pathogenic associations. Henceforth, the endosymbionts in L. pallidum were predicted using the NCBI microbial draft genomes and mitochondrial genome. Besides, this L. pallidum draft genome can be used as a significant reference for comparative genomic studies across mite species.

The body and head lice (Pediculus humanus humanus and Pediculus humanus capitis, respectively) are hematophagous ectoparasites of humans and only the body louse between two is known to transmit three bacterial diseases through its feces. The proliferation profiles of Bartonella quintana, the causative agent of trench fever, inside the louse body and its excretion patterns were investigated in the two louse subspecies following oral challenge with B. quintana-infected blood meal. The initial density of B. quintana was sustained inside head lice without any noticeable proliferation for the entire period after infection. In contrast, B. quintana proliferated rapidly inside body lice and the maximum density reached at 10 days post-infection. The numbers of bacteria detected in feces from infected lice were almost the same and steadily decreased over time in both body and head lice. Nevertheless, the viability of the bacteria, as determined by fluorescence, was significantly higher in body louse feces, especially at 1 day post-infection and this tendency lasted for 11 days. These findings suggest that excretion of feces containing more viable B. quintana that is proliferated inside body lice following ingestion of infected blood meal is responsible for the higher vector competence of body lice.

Body and head lice (Pediculus humanus humanus and Pediculus humanus capitis, respectively) are typical ectoparasites of humans. They differ not only in the ecological habitat but also in the vector competence in spite of their conspecific nature. Only body lice transmit several bacterial pathogens to humans, including Bartonella quintana, Rickettsia prowazekii and Borrelia recurrentis. In this study, the proliferation rates of two model bacteria, a gram positive Staphylococcus aureus and a gram negative Escherichia coli, were determined following bacterial challenge by cuticular injection. Both bacteria proliferated rapidly in body lice at the early stage of bacterial challenge but not in head lice, suggesting that head lice have more sensitive immune responses to these bacteria. In vivo phagocytosis assay revealed that head lice have much higher phagocytic activity against E. coli than body lice whereas only slight differences in phagocytic activity against S. aureus were observed between the two lice species. Taken together, these findings suggest that the reduced phagocytosis activity of body lice contributes, at least in part, to their higher vector competence.