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Universal coverage with effective vector control remains the mainstay of malaria vector control in sub-Saharan Africa. Tanzania has utilized a number of mechanisms for the maintenance of long-lasting insecticidal net (LLIN) coverage over time. Schools have been identified as one potential channel for continuous distribution of LLIN. This research aims to evaluate an annual school-based LLIN distribution programme in Tanzania that began in 2013, called the School Net Programme (SNP). Following each of the first four rounds of SNP distribution, a household survey was conducted in intervention and comparison districts in Southern and Lake zones of Tanzania (N = 5083 households). Measures of ownership, access and use were compared between intervention and comparison districts. Determinants of reach were assessed in intervention districts. Population access to an LLIN increased from 63.1% (95% CI: 58.8, 67.5) to 76.5% (95% CI: 72.9, 80.0) in the intervention districts between the first and last surveys. Access also rose in the comparison districts from 51.4% (95% CI: 46.9, 55.9) to 79.8% (95% CI: 77.3, 82.0) following mass distribution and implementation of school-based distribution during the study period. LLIN use increased in intervention districts from 44.9% (95% CI: 40.5, 49.3) to 65.6% (95% CI: 59.4, 71.8) and from 57.2% (95% CI: 49.7, 64.7) to 77.4% (95% CI: 69.3, 85.5) specifically amongst primary school-aged children. Households reached by the SNP were wealthier households with children enrolled in school. The SNP in Tanzania was able to maintain population level LLIN ownership, use and access in the absence of mass distribution. The SNP successfully reached households that housed school-aged children. Alternative delivery strategies may need to be considered to reach households without children enrolled in schools that experienced fewer benefits from the programme. [ABSTRACT FROM AUTHOR]

As rivers warm, cold‐water fish species may alleviate thermal stress by moving into localized thermal refuges such as cold‐water plumes created by cool tributary inflows. We quantified use of two tributary confluence plumes by juvenile steelhead, Oncorhynchus mykiss, throughout the summer, including how trout positioned themselves in relation to temperature within confluence plumes. At two confluences, Cedar and Elder creeks, along the South Fork Eel River, California, USA, we monitored temperatures using in situ logger grids throughout summer 2016. Fish were counted within confluences via snorkel surveys five times a day on 5 days at each site. We found diel and seasonal dependence on confluence use by steelhead, especially at the Cedar Creek confluence, where mainstem temperatures exceeded 28°C. At this site, fish moved into the confluence on the warmest days and warmest times of the day. Fish observed within the Cedar Creek confluence plume were most common in locations between 20–22°C, rather than the coldest locations (14.5°C). At Elder Creek, where mainstem temperatures remained below 24°C, there was little relationship between mainstem temperature and steelhead presence in the confluence plume. At both sites, steelhead distribution within plumes was influenced by spatial variation of temperature and mean temperature in surveyed grid cells. Our results show that cool tributaries flowing into warmer mainstem reaches (over 24°C) likely create important thermal refuges for juvenile steelhead. As mainstem rivers warm with climate change, cool‐water tributary inputs may become more important for sustaining cold‐water salmonids near the southern end of their range. [ABSTRACT FROM AUTHOR]

Background: Malaria vector control in Tanzania is based on use of long-lasting insecticide treated nets (LLINs) and indoor residual spraying (IRS), which both rely on the use of chemical insecticides. The effectiveness of these control tools is endangered by the development of insecticide resistance in the major malaria vectors. This study was carried out to monitor the susceptibility status of major malaria vectors to insecticides used for IRS and LLINs in mainland Tanzania. Methods: Mosquito larvae were collected in 20 sites of Tanzania mainland in 2015. Phenotypic resistance was determined using standard WHO susceptibility tests. Molecular assay were used to determine distribution of Anopheles gambiae sub-species. A microplate assay approach was used for identifying enzyme levels on single mosquitoes from each sites compared with a susceptible reference strain, An. gambiae sensu stricto (s.s.) Kisumu strain. Results: Anopheles arabiensis was the dominant malaria specie in the country, accounting for 52% of the sibling species identified, while An. gambiae s.s. represented 48%. In Arumeru site, the dominant species was An. arabiensis, which was resistant to both pyrethroids (permethrin and deltamethrin), and pirimiphos-methyl, and had significant elevated levels of GSTs, non-specific esterases, and oxidase enzymes. An. arabiensis was also a dominant species in Kilombero and Kondoa sites, both were resistant to permethrin and deltamethrin with significant activity levels of oxidase enzymes. Resistance to bendiocarb was recorded in Ngara site where specie composition is evenly distributed between An. gambiae s.s. and An.arabiensis. Also bendiocarb resistance was recorded in Mbozi site, where An. gambiae s.s. is the dominant species. Conclusions: Overall, this study confirmed resistance to all four insecticide classes in An. gambiae sensu lato in selected locations in Tanzania. Results are discussed in relation to resistance mechanisms and the optimization of resistance management strategies. [ABSTRACT FROM AUTHOR]

Background: Continuous distribution of insecticide-treated nets (ITNs) has now been accepted as one way of sustaining ITN universal coverage. Community-based channels offer an interesting means of delivering ITNs to households to sustain universal ITN coverage. The objective of this study was to provide proof of concept for this channel. Methods: A 9-month, community-based, distribution pilot was implemented beginning 1 year after a mass campaign in Lainya County, South Sudan from 2012 to 2013. Following social mobilization, community members could request an ITN from a net coupon holder. Eligibility criteria included having lost an ITN, giving birth outside of the health facility, or not having enough ITNs for all household members. After verification, households could exchange the coupon for an ITN at a distribution point. The evaluation was a pre/post design using representative household surveys with two-stage cluster sampling and a sample size of 600 households per survey. Results: At endline, 78% of respondents were aware of the scheme and 89% of those also received an ITN through community-based distribution. Population access to ITNs nearly doubled, from 38% at baseline to 66% after the pilot. Household ownership of any ITN and enough ITNs (1 for 2 people) also increased significantly, from 66 to 82% and 19 to 46%, respectively. Community-based distribution was the only source of ITNs for 53.4% of households. The proportion of the population using an ITN last night increased from 22.7% at baseline to 53.9% at endline. A logistic regression model indicates that although behaviour change communication was positively associated with an increase in ITN use, access to enough nets was the greatest determinant of use. Conclusions: ITN access and use improved significantly in the study area during the pilot, coming close to universal coverage targets. This pilot serves as proof of concept for the community-based distribution methodology implemented as a mechanism to sustain ITN universal coverage. Longer periods of implementation should be evaluated to determine whether community-based distribution can successfully maintain ITN coverage beyond the short term, and reach all wealth quintiles equitably. [ABSTRACT FROM AUTHOR]

Background: Indoor residual spraying (IRS) of households with insecticide is a principal malaria vector control intervention in Zanzibar. In 2006, IRS using the pyrethroid lambda-cyhalothrine was introduced in Zanzibar. Following detection of pyrethroid resistance in 2010, an insecticide resistance management plan was proposed, and IRS using bendiocarb was started in 2011. In 2014, bendiocarb was replaced by pirimiphos methyl. This study investigated the residual efficacy of pirimiphos methyl (Actellic® 300CS) sprayed on common surfaces of human dwellings in Zanzibar. Methods: The residual activity of Actellic 300CS was determined over 9 months through bioassay tests that measured the mortality of female Anopheles mosquitoes, exposed to sprayed surfaces under a WHO cone. The wall surfaces included; mud wall, oil or water painted walls, lime washed wall, un-plastered cement block wall and stone blocks. Insecticide susceptibility testing was done to investigate the resistance status of local malaria vectors against Actellic 300CS using WHO protocols; Anopheline species were identified using PCR methods. Results: Baseline tests conducted one-day post-IRS revealed 100 % mortality on all sprayed surfaces. The residual efficacy of Actellic 300CS was maintained on all sprayed surfaces up to 8 months post-IRS. However, the bioassay test conducted 9 months post-IRS showed the 24 h mortality rate to be ≤80 % for lime wash, mud wall, water paint and stone block surfaces. Only oil paint surface retained the recommended residual efficacy beyond 9 months post-IRS, with mortality maintained at ≥97 %. Results of susceptibility tests showed that malaria vectors in Zanzibar were fully (100 %) susceptible to Actellic 300CS. The predominant mosquito vector species was An. arabiensis (76.0 %) in Pemba and An. gambiae (83.5 %) in Unguja. Conclusion: The microencapsulated formulation of pirimiphos methyl (Actellic 300CS) is a highly effective and appropriate insecticide for IRS use in Zanzibar as it showed a relatively prolonged residual activity compared to other products used for the same purpose. The insecticide extends the residual effect of IRS thereby making it possible to effectively protect communities with a single annual spray round reducing overall costs. The insecticide proved to be a useful alternative in insecticide resistance management plans. [ABSTRACT FROM AUTHOR]

Human abdominal angiostrongyliasis is a potentially fatal disease caused by Angiostrongylus costaricensis, a nematode found in the Americas. During the period of December 1994 through August 1995, an outbreak of this disease occurred in Guatemala. We identified 22 cases of abdominal angiostrongyliasis and conducted a matched case-control study to identify risk factors for illness. The median age of the 18 cases enrolled in the study was 37 years (range, 9–68 years), and 11 (61.1%) were male. Consumption of the following six raw food items was associated with angiostrongyliasis: mint (odds ratio [OR], 6.9; 95% confidence interval [CI], 1.5–66.0), shrimp (OR, infinite; 95% CI, 1.4 to infinite), and four kinds of ceviche that reportedly contained raw mint (OR for consumption of mint or ceviche that contained mint, 7.0; 95% CI, 1.0–315). We conclude that raw mint was the likely vehicle of infection for this outbreak. To our knowledge, this is the first reported outbreak of abdominal angiostrongyliasis and the first time that a specific food item has been epidemiologically linked to the disease. [ABSTRACT FROM PUBLISHER]

Thermal microrefugia, sites within a landscape which are relatively protected from temperature extremes and warming trends, may be necessary for the conservation of animal species as climates warm. In freshwater environments, cold water fish species such as Pacific salmonids already rely on thermal microrefugia to persist in the southern extent of their range. Identifying sites that can provide such thermal microrefugia is essential to inform conservation and management decisions. At present, however, there is no consensus on appropriate ways to identify such sites, and multiple approaches are presented in the literature. Here, we use high resolution thermal data from two cold‐water zones created at the confluence of tributaries with a warm main channel of the South Fork Eel River in Northern California to demonstrate that the characteristics of cold zones identified as thermal microrefugia are not robust to the choice of microrefugium definition. Common definitions disagree on the existence, volume, seasonal temporal trends, and diurnal variations in microrefugia at the two confluences. The disagreements arise from the complex interaction between the confluence mixing regime with diurnal/seasonal warming patterns and how this shapes the distribution of water temperature at the confluences, and how it is classified by each definition. The disagreements cannot be resolved by simple bias correction approaches. Given that all existing definitions rely on simplifications that negate the nuanced way fish use cold water zones and respond to thermal stress, alternative observation and classification approaches may be needed to characterize cold zones in rivers as thermal microrefugia. [ABSTRACT FROM AUTHOR]

High-throughput Plasmodium genomic data is increasingly useful in assessing prevalence of clinically important mutations and malaria transmission patterns. Understanding parasite diversity is important for identification of specific human or parasite populations that can be targeted by control programmes, and to monitor the spread of mutations associated with drug resistance. An up-to-date understanding of regional parasite population dynamics is also critical to monitor the impact of control efforts. However, this data is largely absent from high-burden nations in Africa, and to date, no such analysis has been conducted for malaria parasites in Tanzania countrywide. To this end, over 1,000 P. falciparum clinical isolates were collected in 2017 from 13 sites in seven administrative regions across Tanzania, and parasites were genotyped at 1,800 variable positions genome-wide using molecular inversion probes. Population structure was detectable among Tanzanian P. falciparum parasites, approximately separating parasites from the northern and southern districts and identifying genetically admixed populations in the north. Isolates from nearby districts were more likely to be genetically related compared to parasites sampled from more distant districts. Known drug resistance mutations were seen at increased frequency in northern districts (including two infections carrying pfk13-R561H), and additional variants with undetermined significance for antimalarial resistance also varied by geography. Malaria Indicator Survey (2017) data corresponded with genetic findings, including average region-level complexity-of-infection and malaria prevalence estimates. The parasite populations identified here provide important information on extant spatial patterns of genetic diversity of Tanzanian parasites, to which future surveys of genetic relatedness can be compared., (© 2020 John Wiley & Sons Ltd.)

Background: Indoor residual spraying (IRS) of households with insecticide is a principal malaria vector control intervention in Zanzibar. In 2006, IRS using the pyrethroid lambda-cyhalothrine was introduced in Zanzibar. Following detection of pyrethroid resistance in 2010, an insecticide resistance management plan was proposed, and IRS using bendiocarb was started in 2011. In 2014, bendiocarb was replaced by pirimiphos methyl. This study investigated the residual efficacy of pirimiphos methyl (Actellic 300CS) sprayed on common surfaces of human dwellings in Zanzibar., Methods: The residual activity of Actellic 300CS was determined over 9 months through bioassay tests that measured the mortality of female Anopheles mosquitoes, exposed to sprayed surfaces under a WHO cone. The wall surfaces included; mud wall, oil or water painted walls, lime washed wall, un-plastered cement block wall and stone blocks. Insecticide susceptibility testing was done to investigate the resistance status of local malaria vectors against Actellic 300CS using WHO protocols; Anopheline species were identified using PCR methods., Results: Baseline tests conducted one-day post-IRS revealed 100% mortality on all sprayed surfaces. The residual efficacy of Actellic 300CS was maintained on all sprayed surfaces up to 8 months post-IRS. However, the bioassay test conducted 9 months post-IRS showed the 24 h mortality rate to be ≤80% for lime wash, mud wall, water paint and stone block surfaces. Only oil paint surface retained the recommended residual efficacy beyond 9 months post-IRS, with mortality maintained at ≥97 %. Results of susceptibility tests showed that malaria vectors in Zanzibar were fully (100%) susceptible to Actellic 300CS. The predominant mosquito vector species was An. arabiensis (76.0%) in Pemba and An. gambiae (83.5%) in Unguja., Conclusion: The microencapsulated formulation of pirimiphos methyl (Actellic 300CS) is a highly effective and appropriate insecticide for IRS use in Zanzibar as it showed a relatively prolonged residual activity compared to other products used for the same purpose. The insecticide extends the residual effect of IRS thereby making it possible to effectively protect communities with a single annual spray round reducing overall costs. The insecticide proved to be a useful alternative in insecticide resistance management plans.

Medicine sellers are widely used for fever and malaria treatment in sub-Saharan Africa, but concerns surround the appropriateness of drugs and information provided. Because there is increasing interest in improving their services, we reviewed the literature on their characteristics and interventions to improve their malaria-related practices. Sixteen interventions were identified, involving a mixture of training/capacity building, demand generation, quality assurance, and creating an enabling environment. Although evidence is insufficient to prove which approaches are superior, tentative conclusions were possible. Interventions increased rates of appropriate treatment, and medicine sellers were willing to participate. Features of successful interventions included a comprehensive situation analysis of the legal and market environment; buy-in from medicine sellers, community members and government; use of a combination of approaches; and maintenance of training and supervision. Interventions must be adapted to include artemisinin-based combination therapies, and their sustainability and potential to operate at a national level should be further explored.

Since the mid 1990s, MDMA has been increasingly used as a recreational drug called "Ecstasy" by young people in Europe and the United States. However, despite the widespread recreational use of Ecstasy, systematic data on the psychological and neurobiological effects of MDMA have been scant. To further our understanding of the mechanism of action of MDMA, the authors conducted several studies in healthy human volunteers in an effort to characterize the psychological, cognitive and behavioral effects of MDMA in healthy human volunteers. Prospective placebo-controlled within-subject study designs and standardized psychometric ratings and neuropsychological tests were used to assess the acute, short-term and prolonged effects of the drug. To elucidate the role of various neurotransmitter and receptor systems involved in the action of MDMA in humans, the blocking effects of specific receptor antagonists on MDMA-induced psychological alterations and measures of sensory information processing were studied. To identify the functional neuroanatomy involved in the action of MDMA, Positron Emission Tomography (PET) was used. The present contribution summarizes the acute effect of MDMA on psychological and cognitive measures, information processing, and regional brain activity in healthy human volunteers.