Acceptable performance of grazing cattle frequently depends on the availability of effective broad-spectrum anthelmintics to remove, or prevent infection with, gastrointestinal nematodes. This ...control is increasingly threatened by populations of nematodes resistant to the most commonly used anthelmintics. Although this appears to have developed more slowly than in nematodes infecting small ruminants, the number of reports in the literature over the past five years suggests a rapidly escalating problem. This review discusses this literature, several issues unique to cattle parasitism and anthelmintics, and how previous research in small ruminants can improve the management of anthelmintic resistance in cattle.
This review focuses on the growing popularity of using counter-current chromatography (CCC), with its liquid stationary phase, as one of the prime methods for isolating compounds from Chinese herbal ...medicines (CHMs). 198 publications are reviewed covering 108 different plant species from 56 plant families. These describe the isolation of 354 different molecules across a wide range of polarities, chemical classes and molecular weights (in the range 100–1000
Da). The suitability of CCC for the separation of active compounds from CHM, the phase systems used, how CCC has developed in China, compounds isolated, CCC instrumentation, performance, operational issues and innovations, all supported by detailed cross-referencing, are described. It is concluded that CCC is making an increasingly important contribution to the modernisation of Chinese herbal medicines.
Purpose
The purpose of this paper is to explore the nature of trust in a school community related to the leadership response to crisis.
Design/methodology/approach
This study was a multiple-source ...qualitative study of a single case of a PreK-12 international school called The Learning School.
Findings
The findings revealed the nature of how leadership influences and is influenced by context and community. These led to a discussion about two shifts, the focus on self to focus on others and the collective community, and a shift from a focus on self-preservation and protection to learning and growing together as a community. Communication, decision making, and collaboration in the community played a significant role in the community learning and growing from the crisis.
Research limitations/implications
The study was limited by the nature of the topic, crisis in schools. The nature of crisis limits the ability to engage in inquiry before the crisis, and the inquiry was limited to the specific case that occurred in a unique context. The author proposes future cross-case research to develop an understanding of school and leader responses to crisis varies across individuals and contexts, and culture.
Originality/value
While there is a growing literature about trust, it is difficult to study schools in crisis due to the limitations of the topic and sensitivity of issues of crisis in schools. This study gives insight into the dynamics of leadership and trust in a school in crisis.
The yellow fever mosquito Aedes aegypti is the major vector of dengue, yellow fever, Zika, and Chikungunya viruses. Worldwide vector control is largely based on insecticide treatments but, ...unfortunately, vector control programs are facing operational challenges due to mosquitoes becoming resistant to commonly used insecticides. In Southeast Asia, resistance of Ae. aegypti to chemical insecticides has been documented in several countries but no data regarding insecticide resistance has been reported in Laos. To fill this gap, we assessed the insecticide resistance of 11 Ae. aegypti populations to larvicides and adulticides used in public health operations in the country. We also investigated the underlying molecular mechanisms associated with resistance, including target site mutations and detoxification enzymes putatively involved in metabolic resistance.
Bioassays on adults and larvae collected in five provinces revealed various levels of resistance to organophosphates (malathion and temephos), organochlorine (DDT) and pyrethroids (permethrin and deltamethrin). Synergist bioassays showed a significant increased susceptibility of mosquitoes to insecticides after exposure to detoxification enzyme inhibitors. Biochemical assays confirmed these results by showing significant elevated activities of cytochrome P450 monooxygenases (P450), glutathione S-transferases (GST) and carboxylesterases (CCE) in adults. Two kdr mutations, V1016G and F1534C, were detected by qPCR at low and high frequency, respectively, in all populations tested. A significant negative association between the two kdr mutations was detected. No significant association between kdr mutations frequency (for both 1534C and 1016G) and survival rate to DDT or permethrin (P > 0.05) was detected. Gene Copy Number Variations (CNV) were detected for particular detoxification enzymes. At the population level, the presence of CNV affecting the carboxylesterase CCEAE3A and the two cytochrome P450 CYP6BB2 and CYP6P12 were significantly correlated to insecticide resistance.
These results suggest that both kdr mutations and metabolic resistance mechanisms are present in Laos but their impact on phenotypic resistance may differ in proportion at the population or individual level. Molecular analyses suggest that CNV affecting CCEAE3A previously associated with temephos resistance is also associated with malathion resistance while CNV affecting CYP6BB2 and CYP6P12 are associated with pyrethroid and possibly DDT resistance. The presence of high levels of insecticide resistance in the main arbovirus vector in Laos is worrying and may have important implications for dengue vector control in the country.
Diarrheal diseases are a leading cause of mortality and morbidity, disproportionally affecting persons residing in low and middle-income countries. Accessing high-resolution surveillance data to ...understand community-level etiology and risk remains challenging, particularly in remote and resource limited populations. A multi-year prospective cohort study was conducted in two rural and two peri-urban villages in Cambodia from 2012 to 2018 to describe the epidemiology and etiology of acute diarrheal diseases within the population. Suspected diarrheal episodes among participants were self-reported or detected via routine weekly household visits. Fresh stool and fecal swabs were tested, and acute-illness and follow-up participant questionnaires collected. Of 5027 enrolled participants, 1450 (28.8%) reported at least one diarrheal incident. A total of 4266 individual diarrhea case events were recorded. Diarrhea incidence rate was calculated to be 281.5 persons per 1000 population per year, with an event rate of 664.3 individual diarrhea events occurring per 1000 population per year. Pathogenic Escherichia coli, Aeromonas spp., and Plesiomonas shigelloides were the most prevalent bacterial infections identified. Hookworm and Strongyloides stercoralis were the predominant helminth species, while Blastocystis hominis and Giardia lamblia were the predominant protozoan species found. Norovirus genotype 2 was the predominant virus identified. Mixed infections of two or more pathogens were detected in 36.2% of positive cases. Risk analyses identified unemployed status increased diarrhea risk by 63% (HR = 1.63 95% CI 1.46, 1.83). Individuals without access to protected water sources or sanitation facilities were 59% (HR = 1.59 95% CI 1.49, 1.69) and 19% (HR = 1.19 95% CI 1.12, 1.28) greater risk of contracting diarrhea, respectively. Patient-level surveillance data captured in this long-term study has generated a unique spatiotemporal profile of diarrheal disease in Cambodia. Understanding etiologies, together with associated epidemiological and community-level risk, provides valuable public health insight to support effective planning and delivery of appropriate local population-targeted interventions.
The pharmaceutical industries are looking for rapid methods of purification and predictable scale-up for their drug development process that will cut their costs and enable them to reduce the time to ...market. In this paper, recent progress is reviewed in the development and demonstration of two types of industrial scale centrifugal liquid-liquid chromatography: hydrostatic and hydrodynamic. Industrial scale hydrostatic processes by Partus Technologies and Armen Instrument are just emerging. Results demonstrating scalability are presented for hydrodynamic processes by Dynamic Extractions. The review concludes that the time is now right, with this appropriate commercial support, for high performance counter-current chromatography to emerge as a major enabling technology for industry.
In the last four decades there has been a staggering increase in the geographical range of the arboviral vector Aedes albopictus (Skuse, 1894). This species is now found in every continent except ...Antarctica, increasing the distribution of arboviral diseases such as dengue and chikungunya. In Lao PDR dengue epidemics occur regularly, with cases of chikungunya also reported. As treatment methods for arboviral diseases is limited, the control of the vector mosquitoes are essential. There is a paucity of information on the bionomics and resistance status of this mosquito for successful vector control efforts. Here we describe the bionomics and insecticide resistance status of Ae. albopictus in Laos to identify opportunities for control. Adult Ae. albopictus were collected using human-baited double bed net (HDN) traps in forests, villages and rubber plantations and tested for alpha- and flaviviruses with RT-PCR. Surveys were also conducted to identify larval habitats. Seven adult and larval populations originating from Vientiane Capital and Luang Prabang province were tested against DDT, malathion, permethrin, deltamethrin and, temephos following WHO protocols. Aedes albopictus were found throughout the year, but were six-fold greater in the rainy season than the dry season. Adult females were active for 24 hours, with peak of behaviour at 18.00 h. The secondary forest and rubber plantation samples showed evidence of Pan-flaviviruses, while samples from the villages did not. More than half of the emerged Ae. albopictus were collected from mature rubber plantations (53.9%; 1,533/2,845). Most Ae. albopictus mosquitoes emerged from latex collection cups (19.7%; 562/2,845), small water containers (19.7%; 562/2,845) and tyres (17.4%; 495/2,845). Adult mosquitoes were susceptible to pyrethroids, apart from one population in Vientiane city. All populations were resistant to DDT (between 27-90% mortality) and all except one were resistant to malathion (20-86%). Three of the seven larval populations were resistant to temephos (42-87%), with suspected resistance found in three other populations (92-98%).This study demonstrates that rural areas in northern Laos are potential hot spots for arboviral disease transmission. Multiple-insecticide resistance was found. Aedes albopictus control efforts in villages need to expand to include secondary forests and rubber plantations, with larval source management and limited use of insecticides.
The biofilm matrix is a dynamic environment in which the component microbial cells appear to reach homeostasis and are optimally organized to make use of all available nutrients. The major matrix ...components are microbial cells, polysaccharides and water, together with excreted cellular products. The matrix therefore shows great microheterogeneity, within which numerous microenvironments can exist. Although exopolysaccharides provide the matrix framework, a wide range of enzyme activities can be found within the biofilm, some of which will greatly affect structural integrity and stability.
Highly educated immigrants are part of the growing population of immigrants who are impacted by the increasingly hostile migration policies in the U.S. This qualitative study used a phenomenological ...approach and inductive reasoning to explore the possible impacts of migration integration policies as social determinants of health among this group. Data was collected through 31 semi-structured interviewees with highly educated immigrants who had an intention and interest to stay in the U.S. at the time of the interview. Data were analyzed using reflexive thematic analysis and four main themes emerged: (1) a life overshadowed by silent worries, (2) living through uncertainties and forced decisions as the result of migration integration policies, (3) complexities and challenges of living on a work visa, and (4) shared recommendations by interviewees. Documented narratives as part of this study suggest high rates of stress and anxiety as well as negative mental and physical health outcomes among the participants. Results also suggest high levels of internalized vulnerabilities. Participants shared that migration policies can be enhanced in the U.S. to support highly educated immigrants' growth by creating a better and more transparent communication system, replacing random review processes for applications with systematic procedures, creating expedited pathways to citizenship based on merit, and granting access to work as a basic human right.
PDF
