A comparative evaluation of northern and southern Ixodes scapularis questing height and hiding behaviour in the USA.

Ticks display a distinct type of host-seeking behaviour called questing. It has been proposed that the questing behaviour of Ixodes scapularis explains the geographic variation in Lyme disease (LD) risk in the eastern USA because the northern population has been shown to quest more often than the southern population. The height at which questing occurs is variable and this study aimed to characterize questing height for I. scapularis. Ticks were collected from a northern and southern state (i.e. Maryland and Texas) and bioassays were conducted. We report that nymphs from Texas quested at lower heights compared to nymphs from Maryland. In addition, only Texas nymphs exhibited a behaviour we call 'hiding behaviour'. These results may reflect the different composition of hosts between these two areas as the south has a higher abundance of lizards. In contrast, there was no significant difference in questing height between Maryland adults and Texas adults which was to be expected since adults are feeding on white-tailed deer in both locations. If all southern I. scapularis nymphs are questing at lower heights, this might make them less likely to come into contact with humans and this may be contributing to the geographical difference in LD prevalence.

Trapping White-Tailed Deer (Artiodactyla: Cervidae) in Suburbia for Study of Tick-Host Interaction.

Live capture of white-tailed deer (Odocoileus virginianus) (Zimmermann, 1780) is often necessary for research, population control, disease monitoring, and parasite surveillance. We provide our deer trapping protocol used in a tick-host vector ecology research project and recommendations to improve efficiency of deer trapping programs using drop nets in suburban areas. We captured 125 deer across two trapping seasons. Generally, lower daily minimum temperatures were related to increased capture probability, along with the presence of snow. Our most successful trapping sites were less forested, contained more fragmentation, and greater proportion of human development (buildings, roads, recreational fields). To improve future suburban deer trapping success, trapping efforts should include areas dominated by recreational fields and should not emphasize remote, heavily forested, less fragmented parks. Concurrently, our study illustrated the heterogeneous nature of tick distributions, and we collected most ticks from one trapping site with moderate parameter values between the extremes of the most developed and least developed trapping sites. This emphasized the need to distribute trapping sites to not only increase your capture success but to also trap in areas across varying levels of urbanization and fragmentation to increase the probability of parasite collection.

Feeding and respiratory gas exchange of Rhipicephalus sanguineus sensu lato (Acari: Ixodidae).

Ticks are subject to various environmental constrains, such as dehydration, desiccation and long-waiting for hosts to attach. These factors are crucial for tick survival in the environment. Ticks have developed physiological mechanisms and/or strategies that allow adaptability and survival in the environment in which they live, such as spiracle control and cyclical or discontinuous gas exchanges. However, details of gas exchange profile have been reported only in a few tick species in the past. The present study aims to identify and describe respiratory gas exchange patterns in a tropical population of the brown dog tick Rhipicephalus sanguineus sensu lato and effects of blood feeding. Adult female ticks were fed on rabbit hosts. Partially fed (4 to 6 days) and completely fed (> 9 days) ticks were collected daily during feeding, weighed and subjected to CO2 emission measurement at 25 °C using flow-through respirometry. Unfed adult females showed a well-defined periodical burst of CO2 emissions, followed by short periods of low-emission intercepts. The fed groups had drastic changes in respiratory profiles with semi-engorged females showing a high-intensity respiratory pattern alternating between continuous and discontinuous and the engorged females showing a continuous respiratory pattern with high frequency and intensity. The findings from this study contribute to a better understanding of the respiratory physiological process of a tropical population of the dog tick, which may help future investigations on other biological aspects of this ectoparasite and development of control measures.

Mosquito and tick repellency of two Anthemis essential oils from Saudi Arabia.

The essential oils (EOs) of Anthemis melampodina (Am) and Anthemis scrobicularis (As) (Asteraceae) were extracted from the aerial parts of the plants by hydrodistillation, and their chemical compositions were analyzed using GC-FID and GC-MS. Fifty-six components representing 85.5% of the oil composition of Anthemis melampdina were identified, and the major components were α-pinene (17.1%) and ß-eudesmol (13.8%). Forty-one components representing 86% of the oil composition of Anthemis scrobicularis were identified, and the major component was ß-eudesmol (12.8%). Laboratory bioassays were conducted to determine repellency of Am and As EOs against the yellow fever mosquito Aedes aegypti L. and the lone star tick Amblyomma americanum L. The minimum effective doses (MEDs) of the Am and As EOs against mosquitoes were 0.187 ±â€¯0.000 and 0.312 ±â€¯0.063 mg/cm2 respectively, which were significantly higher than that of DEET (0.023 ±â€¯0.000 mg/cm2) in human-based repellent bioassays. The As EO was more repellent than Am EO against nymphal ticks but was less effective than DEET in vertical paper bioassays.

Evaluation of four commercial natural products for repellency and toxicity against the lone star tick, Amblyomma americanum (Acari: Ixodidae).

Lone star ticks are aggressive ectoparasites of domestic and wild animals, as well as humans. These ticks can transmit many pathogens that cause disease including Erhlichia and tularemia. Common compounds used for personal protection and area sprays are N-diethyl-3-methyl benzamide (DEET) and permethrin, but public concern over personal and environmental safety require the development of new, safer products. In the current study, four commercially available products (Wondercide, Essentria IC3, Vet's Best, and Mosquito Barrier) were tested for both repellent and toxic effects against lone star tick nymphs and adults. Overall, all four products were more effective against nymphs than against adults. Wondercide and Essentria IC3 were as toxic to nymphs as permethrin at concentrations of 3.13% and higher, and as repellent as DEET at all concentrations. Nymphs were also repelled by Mosquito Barrier and Vet's Best, but these products had about half or less of the repellent effects of Wondercide and Essentria IC3 at most of the concentrations. Adult ticks were repelled similarly by all products at all tested concentrations, but at lower levels than nymphs. Toxicity of the four tested products on adults was similar at concentrations of 12.5% and below, less than half of what was observed with permethrin with declining effectiveness as concentrations decreased. Overall, these four products may offer a natural way to repel lone star ticks, but further field testing is needed to determine rates of application and residual activity.

TRANSLATING ECOLOGY, PHYSIOLOGY, BIOCHEMISTRY, AND POPULATION GENETICS RESEARCH TO MEET THE CHALLENGE OF TICK AND TICK-BORNE DISEASES IN NORTH AMERICA.

Emerging and re-emerging tick-borne diseases threaten public health and the wellbeing of domestic animals and wildlife globally. The adoption of an evolutionary ecology framework aimed to diminish the impact of tick-borne diseases needs to be part of strategies to protect human and animal populations. We present a review of current knowledge on the adaptation of ticks to their environment, and the impact that global change could have on their geographic distribution in North America. Environmental pressures will affect tick population genetics by selecting genotypes able to withstand new and changing environments and by altering the connectivity and isolation of several tick populations. Research in these areas is particularly lacking in the southern United States and most of Mexico with knowledge gaps on the ecology of these diseases, including a void in the identity of reservoir hosts for several tick-borne pathogens. Additionally, the way in which anthropogenic changes to landscapes may influence tick-borne disease ecology remains to be fully understood. Enhanced knowledge in these areas is needed in order to implement effective and sustainable integrated tick management strategies. We propose to refocus ecology studies with emphasis on metacommunity-based approaches to enable a holistic perspective addressing whole pathogen and host assemblages. Network analyses could be used to develop mechanistic models involving multihost-pathogen communities. An increase in our understanding of the ecology of tick-borne diseases across their geographic distribution will aid in the design of effective area-wide tick control strategies aimed to diminish the burden of pathogens transmitted by ticks.

Evaluation of DEET and eight essential oils for repellency against nymphs of the lone star tick, Amblyomma americanum (Acari: Ixodidae).

DEET and Eight commercially available essential oils (oregano, clove, thyme, vetiver, sandalwood, cinnamon, cedarwood, and peppermint) were evaluated for repellency against host-seeking nymphs of the lone star tick, Amblyomma americanum. Concentration-repellency response was established using the vertical paper bioassay technique for each essential oil and compared with that of N,N-diethyl-3-methyl benzamide (DEET), a standard repellent compound present in many commercial repellent formulations. The effective concentration of DEET that repels 50% of ticks (EC50) was estimated at 0.02 mg/cm(2), while EC50s of the essential oils fall between 0.113 and 0.297 mg/cm(2). Based on EC50 estimates, oregano essential oil was the most effective among all essential oils tested, followed by clove, thyme, vetiver, sandalwood, cinnamon, cedarwood, and peppermint oils. None of the tested essential oils demonstrated a level of tick repellency found with DEET. Results from this study illustrated the challenge in search for more effective natural tick repellents.

Acetylcholinesterase 1 in populations of organophosphate-resistant North American strains of the cattle tick, Rhipicephalus microplus (Acari: Ixodidae).

Rhipicephalus microplus, the cattle fever tick, is a global economic problem to the cattle industry due to direct infestation of cattle and pathogens transmitted during feeding. Cattle fever tick outbreaks continue to occur along the Mexico-US border even though the tick has been eradicated from the USA. The organophosphate (OP) coumaphos targets acetylcholinesterase (AChE) and is the approved acaricide for eradicating cattle fever tick outbreaks. There is evidence for coumaphos resistance developing in cattle ticks in Mexico, and OP-resistant R. microplus ticks were discovered in outbreak populations of Texas in 2005. The molecular basis of coumaphos resistance is not known, and our study was established to gather further information on whether AChE1 is involved in the resistance mechanism. We also sought information on allele diversity in tick populations with different levels of coumaphos resistance. The overarching project goal was to define OP resistance-associated gene mutations such that a DNA-based diagnostic assay could be developed to assist the management of resistance. Three different AChE transcripts have been reported in R. microplus, and supporting genomic and transcriptomic data are available at CattleTickBase. Here, we report the complete R. microplus AChE1 gene ascertained by sequencing a bacterial artificial chromosome clone containing the entire coding region and the flanking 5' and 3' regions. We also report AChE1 sequences of larval ticks from R. microplus strains having different sensitivities to OP. To accomplish this, we sequenced a 669-bp region of the AChE1 gene corresponding to a 223 amino acid region of exon 2 to assess alleles in seven strains of R. microplus with varying OP resistance phenotypes. We identified 72 AChE1 sequence variants, 2 of which are strongly associated with OP-resistant phenotypes. Esterase-like sequences from the R. microplus transcriptome RmiTr Version 1.0 were compared to the available sequence databases to identify other transcripts with similarity to AChE1.

Surface Polar Lipids Differ in Male and Female Phlebotomus papatasi (Diptera: Psychodidae).

The polar lipids on the surface of the Old World sand fly, Phlebotomus papatasi (Scopoli), were analyzed by high-resolution mass spectrometry. Blood-fed females and nonblood-fed females and males were separately analyzed and compared. The major polar lipids were found to be long-chain diols and fatty acids. Relatively high levels of diacylglycerols were found in blood-fed females and in males. A wide variety of lipids were found at low levels, including esters, sterols, monoacylglycerols, and hydroxy fatty acids. Blood-fed females had several lyso lipids and N-acyl amino acids that were not found on unfed females or males. These substances may be surfactants used in blood feeding. Heneicosenoic acid was found on females at more than twice the level of males, suggesting it could be a component of a female pheromone. Four substances were identified on males at twofold higher levels than on females: tetradienoic acid, methoxyhexadecasphinganine, butyl octadecanoate, and diacylglycerol(14:1/12:0/0:0). These could be short-range pheromones involved in courtship, and they will be further analyzed in future behavioral bioassays.

Surface Polar Lipids Differ in Male and Female Phlebotomus papatasi (Diptera: Psychodidae).

The polar lipids on the surface of the Old World sand fly, Phlebotomus papatasi (Scopoli), were analyzed by high-resolution mass spectrometry. Blood-fed females and nonblood-fed females and males were separately analyzed and compared. The major polar lipids were found to be long-chain diols and fatty acids. Relatively high levels of diacylglycerols were found in blood-fed females and in males. A wide variety of lipids were found at low levels, including esters, sterols, monoacylglycerols, and hydroxy fatty acids. Blood-fed females had several lyso lipids and N-acyl amino acids that were not found on unfed females or males. These substances may be surfactants used in blood feeding. Heneicosenoic acid was found on females at more than twice the level of males, suggesting it could be a component of a female pheromone. Four substances were identified on males at twofold higher levels than on females: tetradienoic acid, methoxyhexadecasphinganine, butyl octadecanoate, and diacylglycerol(14:1/12:0/0:0). These could be short-range pheromones involved in courtship, and they will be further analyzed in future behavioral bioassays.

Repellent activity of essential oils to the Lone Star tick, Amblyomma americanum.

BACKGROUND: The Lone Star tick, Amblyomma americanum is important to human health because of a variety of pathogenic organisms transmitted to humans during feeding events, which underscores the need to identify novel approaches to prevent tick bites. Thus, the goal of this study was to test natural and synthetic molecules for repellent activity against ticks in spatial, contact and human fingertip bioassays. METHODS: The efficacy of essential oils and naturally derived compounds as repellents to Am. americanum nymphs was compared in three different bioassays: contact, spatial and fingertip repellent bioassays. RESULTS: Concentration response curves after contact exposure to 1R-trans-chrysanthemic acid (TCA) indicated a 5.6 µg/cm2 concentration required to repel 50% of ticks (RC50), which was five- and sevenfold more active than DEET and nootkatone, respectively. For contact repellency, the rank order of repellency at 50 µg/cm2 for natural oils was clove > geranium > oregano > cedarwood > thyme > amyris > patchouli > citronella > juniper berry > peppermint > cassia. For spatial bioassays, TCA was approximately twofold more active than DEET and nootkatone at 50 µg/cm2 but was not significantly different at 10 µg/cm2. In spatial assays, thyme and cassia were the most active compounds tested with 100% and 80% ticks repelled within 15 min of exposure respectively and was approximately twofold more effective than DEET at the same concentration. To translate these non-host assays to efficacy when used on the human host, we quantified repellency using a finger-climbing assay. TCA, nootkatone and DEET were equally effective in the fingertip assay, and patchouli oil was the only natural oil that significantly repelled ticks. CONCLUSIONS: The differences in repellent potency based on the assay type suggests that the ability to discover active tick repellents suitable for development may be more complicated than with other arthropod species; furthermore, the field delivery mechanism must be considered early in development to ensure translation to field efficacy. TCA, which is naturally derived, is a promising candidate for a tick repellent that has comparable repellency to commercialized tick repellents.

Aggressive interactions among white-tailed deer (Artiodactyla: Cervidae) at 4-poster devices for host-targeted tick control.

White-tailed deer, Odocoileus virginianus Zimmermann (Artiodactyla: Cervidae), are the primary wildlife host for adult stages of blacklegged ticks (Acari: Ixodidae: Ixodes scapularis Say) and an important host for lone star ticks (Acari: Ixodidae: Amblyomma americanum Linnaeus), both of which are vectors of numerous tick-borne pathogens. The 4-poster passive deer treatment device is a topical, host-targeted method to control free-living tick populations and has been proven to successfully reduce tick abundance in several states. Aggressive behavior of white-tailed deer at concentrated feeding stations is hypothesized to interfere with the effective use of 4-poster devices and deer contact with acaricide applicators. We analyzed images collected by camera traps at 4-poster feeding stations deployed at 3 sites in Maryland and found a negative relationship between some aggressive interactions and contact with applicators. Our results emphasize the need for further investigation into whether deer social dynamics can impact 4-poster efficacy for tick control. This study serves as a reminder that intraspecific interactions are important to consider when using host-targeted acaricide approaches.

A Clinical Perspective on Plasma Cell Leukemia: A Single-Center Experience.

Circulating plasma cells (CPCs) are detected in most multiple myeloma (MM) patients, both at diagnosis and on relapse. A small subset, plasma cell leukemia (PCL), represents a different biology and has a poor prognosis. In this retrospective analysis, we evaluated patients with primary (pPCL, n = 35) or secondary (sPCL, n = 49), with ≥5% CPCs and a smaller subset with lower CPCs of 1-4% (n = 20). The median age was 61 years; 45% were men and 54% were Black. High-risk cytogenetics were found in 87% and extramedullary disease in 47%. For the entire cohort, 75% received a proteasome inhibitor, 70% chemotherapy, 54% an immunomodulatory drug, 24% a daratumumab-based regimen and 26% an autologous stem cell transplant (ASCT). The treatments marginally improved the overall survival (OS) for pPCL vs. sPCL (13 vs. 3.5 months p = 0.002). However, the 5-year survival for the whole cohort was dismal at 11%. High-risk cytogenetics, low platelets, extramedullary disease and high LDH were independently associated with poor outcomes. Further research is urgently needed to expand the treatment options and improve the outcomes in PCL.

In Vitro Evaluation of Essential Oils and Saturated Fatty Acids for Repellency against the Old-World Sand Fly, Phlebotomus papatasi (Scopoli) (Diptera: Psychodidae).

The sand fly, Phlebotomus papatasi (Scopoli, 1786), is a major vector for Leishmania major in the Middle East, which has impacted human health and US military operations in the area, demonstrating the need to develop effective sand fly control and repellent options. Here, we report the results of spatial repellency and avoidance experiments in a static air olfactometer using the female P. papatasi testing essential oils of Lippia graveolens (Mexican oregano), Pimenta dioica (allspice), Amyris balsamifera (amyris), Nepeta cataria (catnip), Mentha piperita (peppermint), and Melaleuca alternifolia (tea tree); the 9-12 carbon saturated fatty acids (nonanoic acid, decanoic acid, undecanoic acid, and dodecanoic acid); and the synthetic repellents DEET and IR3535. The materials applied at 1% exhibited varying activity levels but were not significantly different in mean repellency and avoidance from DEET and IR3535, except in regards to nonanoic acid. Some materials, particularly nonanoic and undecanoic acids, produced sand fly mortality. The observed trends in mean repellency over exposure time included the following: (1) P. dioica oil, M. alternifolia oil, decanoic acid, undecanoic acid, DEET, and IR3535 exhibited increasing mean repellency over time; (2) oils of N. cataria, A. balsamifera, M. piperita, and dodecanoic acid exhibited relatively constant mean repellency over time; and (3) L. graveolens oil and nonanoic acid exhibited a general decrease in mean repellent activity over time. These studies identified the essential oils of N. cataria and A. balsamifera as effective spatial repellents at reduced concentrations compared to those of DEET. Additional research is required to elucidate the modes of action and potential synergism of repellents and essential oil components for enhanced repellency activity.

Parasitoid-induced changes in metabolic rate and feeding activity of the emerald ash borer (Coleoptera: Buprestidae): implications for biological control.

Parasitoid-host interactions form the foundation of biological control strategies against many agriculture and forest insect pests. The emerald ash borer (EAB), Agrilus planipennis (Coleoptera: Buprestidae), is a serious invasive pest of ash (Fraxinus spp.) trees in North America. Tetrastichus planipennisi (Hymenoptera: Eulophidae) is a gregarious, koinobiont endoparasitoid, attacking late (3rd to 4th) instars of EAB larvae, which feed in the live phloem of ash trunks or branches, making serpentine-like galleries filled with larval frass. In the present study, we tested the hypothesis that T. planipennisi regulates the host metabolism and feeding activity to optimize its offspring development and fitness. We first compared the respiration rate of parasitized and unparasitized host larvae at different times after parasitism, and then measured feeding activity of both parasitized and unparasitized host larvae inside their feeding galleries. Although parasitized host larvae increased metabolic rate and feeding activity in the first few days of parasitism, T. planipennisi parasitism induced an overall reduction of the metabolic rate and decrease in feeding activity of parasitized host larvae over their development period. In addition, there was a negative relationship between feeding activity of parasitized hosts and brood sizes of the parasitoid progeny-i.e., the more parasitoid progeny a host larva received, the less feeding activity the host had. These findings suggest that T. planipennisi has limited ability to optimize its offspring development and fitness through regulations of the host metabolism and feeding activity and its parasitism reduces feeding damage of parasitized EAB larvae to infested ash trees.

Zoonotic implications of white-footed mice habitat selection and territoriality in fragmented landscapes.

White-footed mouse (Peromyscus leucopus) populations can thrive in fragmented suburban and urban parks and residential spaces and play a pivotal role in the spread and prevalence of tick-borne diseases. We collected spatial data on 58 individual mice living at the intersection of county park land and residential land in suburban Howard County, MD, U.S.A. We analyzed mouse density, home-range size and overlap, and a Bayesian mixed-effects model to identify the habitats where they were found relative to where they were caught, as well as a resource selection function for general habitat use. We found that as mouse density increased, home-range size decreased. The overlap indices and the resource selection function supported territoriality coupled with site-specific space use in these suburban mouse populations. While mice occurred in open areas, forest edge, and forest, they showed a strong preference for forested areas. Interestingly, mice captured only 30 to 40 m into the forest rarely used the nearby private yards or human structures and this has direct implications for the placement of rodent-targeted tick control treatments. Our study supports the need for zoonotic disease management frameworks that are based on site-specific land cover characteristics as well as specific management objectives.

Lactate Dehydrogenase Inhibitors Suppress Borrelia burgdorferi Growth In Vitro.

Borrelia burgdorferi, the causative agent of Lyme disease, has a highly reduced genome and relies heavily on glycolysis for carbon metabolism. As such, established inhibitors of lactate dehydrogenase (LDH) were evaluated in cultures to determine the extent of their impacts on B. burgdorferi growth. Both racemic and enantiopure (AT-101) gossypol, as well as oxamate, galloflavin, and stiripentol, caused the dose-dependent suppression of B. burgdorferi growth in vitro. Racemic gossypol and AT-101 were shown to fully inhibit spirochetal growth at concentrations of 70.5 and 187.5 µM, respectively. Differences between racemic gossypol and AT-101 efficacy may indicate that the dextrorotatory enantiomer of gossypol is a more effective inhibitor of B. burgdorferi growth than the levorotatory enantiomer. As a whole, LDH inhibition appears to be a promising mechanism for suppressing Borrelia growth, particularly with bulky LDH inhibitors like gossypol.

Ixodes scapularis Is the Most Susceptible of the Three Canonical Human-Biting Tick Species of North America to Repellent and Acaricidal Effects of the Natural Sesquiterpene, (+)-Nootkatone.

Ticks are vectors of many human and animal zoonotic disease-causing agents causing significant global health and economic strain. Repellents and acaricides are integral to the human capacity for personal protection from tick bites. Nootkatone, a naturally occurring sesquiterpene found in the Alaskan cedar tree, grapefruit, and other sources, has been documented to be a potent acaricide. Research has also noted repellent effects against some tick species. In this study, our aim was to investigate the effect of synthetic, high-purity (+)-nootkatone on adult Ixodes scapularis, Dermacentor variabilis, and Amblyomma americanum ticks in an in vitro, vertical filter paper bioassay. (+)-nootkatone showed compelling tick repellency, but median effective concentrations (EC50) significantly differed among species. Ixodes scapularis were repelled at very low concentrations (EC50 = 0.87 ± 0.05 µg/cm2). Higher concentrations were required to repel D. variabilis (EC50 = 252 ± 12 µg/cm2) and A. americanum (EC50 = 2313 ± 179 µg/cm2). Significant post-exposure mortality, assessed 24 h after repellency trials, was also observed in I. scapularis but was absent entirely in D. variabilis and A. americanum. These tests demonstrate that nootkatone has a promising dual-action personal protection capacity against adult I. scapularis ticks, warranting further investigation in more natural environments and in the presence of host cues.

Association of anticoagulation use during continuous kidney replacement therapy and 90-day outcomes: A multicentre study.

Introduction: Anticoagulation is recommended during continuous kidney replacement therapy (CKRT) to prolong the filter lifespan for optimal filter performance. We aimed to evaluate the effect of anticoagulation during CKRT on dialysis dependence and mortality within 90 days of intensive care unit (ICU) admission. Method: Our retrospective observational study evaluated the first CKRT session in critically ill adults with acute kidney injury (AKI) in Singapore from April to September 2017. The primary outcome was a composite of dialysis dependence or death within 90 days of ICU admission; the main exposure variable was anticoagulation use (regional citrate anticoagulation [RCA] or systemic heparin). Multivariable logistic regression was performed to adjust for possible confounders: age, female sex, Acute Physiology and Chronic Health Evaluation (APACHE II) score, liver dysfunction, coagulopathy (international normalised ratio[INR] >1.5) and platelet counts of less than 100,000/uL). Results: The study cohort included 276 patients from 14 participating adult ICUs, of whom 176 (63.8%) experienced dialysis dependence or death within 90 days of ICU admission (19 dialysis dependence, 157 death). Anticoagulation significantly reduced the odds of the primary outcome (adjusted odds ratio [AOR] 0.47, 95% confidence interval [CI] 0.27-0.83, P=0.009). Logistic regression analysis using anticoagulation as a 3-level indicator variable demonstrated that RCA was associated with mortality reduction (AOR 0.46, 95% CI 0.25-0.83, P=0.011), with heparin having a consistent trend (AOR 0.51, 95% CI 0.23-1.14, P=0.102). Conclusion: Among critically ill patients with AKI, anticoagulation use during CKRT was associated with reduced dialysis or death at 90 days post-ICU admission, which was statistically significant for regional citrate anticoagulation and trended in the same direction of benefit for systemic heparin anticoagulation. Anticoagulation during CKRT should be considered whenever possible.

Behavior of Nymphs and Adults of the Black-Legged Tick Ixodes scapularis and the Lone Star Tick Ambylomma americanum in Response to Thermal Stimuli.

Ticks use chemical and thermal signals emitted by humans and other vertebrates to locate suitable hosts for a blood meal. Here, we study the behavior of black-legged Ixodes scapularis and the lone star ticks Amblyomma americanum exposed to heat sources held at temperatures near those of vertebrate hosts (32 °C). First, we used a locomotion compensator to test behavioral responses of ticks to an infrared light emitting diode (LED). The servosphere allowed us to measure parameters such as velocity, acceleration, linearity, and orientation. Then a heating element (Peltier) located in one of the extremes of a double-choice vertical rod (flying T), was employed to observe upward movement of the ticks toward such a heat source. While both species oriented toward the LED, only lone star ticks were attracted to the Peltier element while climbing upward. In conclusion, we showed that heat attracted ticks from short distances up to several centimeters on a the servosphere, and those responses differed between the two species of ticks on the flying T. We discuss our results in the context of the ecology of both tick species and their potential in tick survey and management.