Prevalence and distribution of pathogen infection and permethrin resistance in tropical and temperate populations of Rhipicephalus sanguineus s.l. collected worldwide.

The brown dog tick, Rhipicephalus sanguineus sensu lato (s.l.) Latreille (Acari: Ixodidae), is a peridomestic, cosmopolitan parasite of dogs known to vector numerous pathogens of veterinary and medical importance. Recent phylogenetic analyses separate this tick into temperate and tropical lineages. Populations of Rh. sanguineus s.l. have been reported to exhibit sodium channel target site insensitivity to permethrin and etofenprox, which is likely due to the prolonged use of pyrethroids against many pests in and around the home. In this study, populations collected in the Caribbean, Africa, Asia, Europe and North America, were tested to identify the distribution of a known resistance mechanism, pathogen-vector interactions and phylogeny in relation to latitude. Using molecular assays, populations from 29 distinct locations were simultaneously geographically typed and screened for bacterial infection by Rickettsia, Ehrlichia, Babesia and Hepatozoon species, and for the presence of a sodium channel single nucleotide polymorphism known to confer permethrin resistance. Implications of these results on Rh. sanguineus s.l. management in association with geographical distribution will be discussed.

Auto-dissemination of commercially available fungal pathogens in a laboratory assay for management of the brown dog tick Rhipicephalus sanguineus.

Rhipicephalus sanguineus is a canine tick that infests dogs throughout the world and is frequently found in homes and dog kennels. Management of this tick species is complicated by the presence of resistance to commonly utilized acaricides. Fungal formulations could provide a valuable alternative tool for management and are especially relevant indoors where detrimental environmental effects on fungal spores are of less concern. Two commercially available fungal formulations, one containing Metarhizium anisopliae and the other containing Beauveria bassiana, were compared for time to death and sporulation in nymphal ticks exposed for 60 min in treated filter paper packets. Beauveria bassiana exposure killed ticks faster than M. anisopliae exposure and B. bassiana was more likely to sporulate on tick cadavers than M. anisopliae. To determine whether infected ticks could disseminate fungus to their conspecifics, ticks were marked and treated with fungus before being placed with untreated ticks. Fungus was successfully transmitted from treated to untreated ticks. Mortality of ticks exposed to B. bassiana-exposed conspecifics occurred sooner than for those exposed to M. anisopliae-exposed conspecifics, indicating faster dissemination in the former. Therefore, although both formulations resulted in decreased longevity of ticks compared with the controls, the B. bassiana formulation holds the most promise for direct or indirect application with respect to brown dog tick management.

Permethrin and malathion LD90 values for Culex quinquefasciatus vary with topical application site.

Prior research in multiple insect species has demonstrated that insecticide-induced mortality varies according to the body region exposed on the insect. This variation has been demonstrated in Culex quinquefasciatus Say (Diptera: Culicidae), but has not been quantified using dose-response curves. Applications of technical permethrin or malathion to one of three body regions on Cx. quinquefasciatus resulted in dose-response curves that were not equivalent to one another. The generated LD90 values and curves for each body region were compared with previously reported LD values for analogous sites in several mosquito species, specifically the mesothorax. Based on the present results, the permethrin and malathion LD50 and LD90 concentrations required for droplets impinging on the abdomen and mesothorax of Cx. quinquefasciatus when applied through ground-based spray systems utilized by mosquito control programmes were calculated.

Determination of metabolic resistance mechanisms in pyrethroid-resistant and fipronil-tolerant brown dog ticks.

Rhipicephalus sanguineus (Latreille) (Ixodida: Ixodidae) is a three-host dog tick found worldwide that is able to complete its' entire lifecycle indoors. Options for the management of R. sanguineus are limited and its' control relies largely on only a few acaricidal active ingredients. Previous studies have confirmed permethrin resistance and fipronil tolerance in R. sanguineus populations, commonly conferred by metabolic detoxification or target site mutations. Herein, five strains of permethrin-resistant and three strains of fipronil-tolerant ticks were evaluated for metabolic resistance using synergists to block metabolic enzymes. Synergist studies were completed with triphenyl phosphate (TPP) for esterase inhibition, piperonyl butoxide (PBO) for cytochrome P450 inhibition, and diethyl maleate (DEM) for glutathione-S-transferase inhibition. Additionally, increased esterase activity was confirmed using gel electrophoresis. The most important metabolic detoxification mechanism in permethrin-resistant ticks was increased esterase activity, followed by increased cytochrome P450 activity. The inhibition of metabolic enzymes did not have a marked impact on fipronil-tolerant tick strains.

Effects of four commercial fungal formulations on mortality and sporulation in house flies (Musca domestica) and stable flies (Stomoxys calcitrans).

The house fly Musca domestica L. (Diptera: Muscidae) and stable fly Stomoxys calcitrans (L.) (Diptera: Muscidae) are major pests of livestock. Biological control is an important tool in an integrated control framework. Increased mortality in filth flies has been documented with entomopathogenic fungi, several strains of which are commercially available. Three strains of Beauveria bassiana (Balsamo-Crivelli) Vuillemin (Hypocreales: Cordycipitaceae) and one strain of Metarhizium brunneum (Petch) (Hypocreales: Clavicipitaceae) were tested in commercial formulations for pathogenicity against house flies and stable flies. There was a significant increase in mortality of house flies with three of the formulations, BotaniGard® ES, Mycotrol® O, and Met52® EC, during days 4-9 in comparison with balEnce™ and the control. In stable flies, mortality rates were highest with Met52® EC, followed by Mycotrol® O, BotaniGard® ES and, finally, balEnce™. There was a significant fungal effect on sporulation in both house flies and stable flies. Product formulation, species differences and fungal strains may be responsible for some of the differences observed. Future testing in field situations is necessary. These commercial biopesticides may represent important tools in integrated fly management programmes.

Does behaviour play a role in house fly resistance to imidacloprid-containing baits?

The objective of this research was to examine the role and type of behavioural mechanisms that function in house fly, Musca domestica L. (Diptera: Muscidae), resistance to an imidacloprid-containing commercial fly bait, QuickBayt(®) , using an insecticide-susceptible and an imidacloprid-resistant strain. Mortality and feeding behaviour were observed through choice bioassays of three post-imidacloprid selected house fly generations to determine whether flies would consume the bait in the presence of an alternative food source. Mortality rates in choice containers progressively decreased in post-selection flies as QuickBayt(®) no-choice selections proceeded. There were no differences between the proportions of flies observed contacting QuickBayt(®) and sugar, respectively, a finding that eliminates repellency as a mechanism of stimulus-dependent behavioural resistance. However, differences in QuickBayt(®) consumption and subsequent mortality between choice and no-choice containers provided strong support for the evolution of consumption irritancy- or taste aversion-related behavioural resistance. The results of this study support the responsible rotation of insecticide bait formulations for house fly control.

Long-term survivor characteristics in HER2-positive metastatic breast cancer from registHER.

BACKGROUND: Data characterising long-term survivors (LTS) with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC) are limited. This analysis describes LTS using registHER observational study data. METHODS: A latent class modelling (LCM) approach was used to identify distinct homogenous patient groups (or classes) based on progression-free survival (PFS), overall survival, and complete response. Demographics, clinicopathologic factors, first-line treatment patterns, and clinical outcomes were described for each class. Class-associated factors were evaluated using logistic regression analysis. RESULTS: LCM identified two survivor groups labelled as LTS (n=244) and short-term survivors (STS; n=757). Baseline characteristics were similar between groups, although LTS were more likely to be white (83.6% vs 77.8%) with oestrogen receptor-positive (ER+) or progesterone receptor-positive (PgR+) disease (59.4% vs 50.9%). Median PFS in LTS was 37.2 (95% confidence interval (CI): 32.9-40.5) vs 7.3 months (95% CI: 6.8-8.0) in STS. Factors associated with long-term survival included ER+ or PgR+ disease, metastasis to node/local sites, first-line trastuzumab use, and first-line taxane use. CONCLUSIONS: Prognostic variables identified by LCM define a HER2-positive MBC patient profile and therapies that may be associated with more favourable long-term outcomes, enabling treatment selection appropriate to the patient's disease characteristics.

Comparison of ectoparasite communities of sylvatic and urban wild mesomammals and unowned community cats in north-central Florida.

The adaptation of wildlife species to urban environments can drive changes in the ecology of ectoparasites and vector-borne disease. To better understand ectoparasite dynamics in an urban environment, we investigated the ectoparasite communities of 183 sylvatic and urban opossums and raccoons captured across four seasons at a rural research station and within the city of Gainesville, FL, and of 115 community cats from the Gainesville, FL area. Amblyomma americanum (L.) (Acari: Ixodidae), Dermacentor variabilis (Say), and Ixodes texanus Banks were collected from raccoons, A. americanum, D. variabilis, and Ixodes scapularis Say from opossums, and A. americanum from cats. Few ticks were collected from urban animals, although species richness of ectoparasites was similar between urban and sylvatic habitats. Ctenocephalides felis (Bouché) (Siphonaptera: Pulicidae) was collected from all sampled host species, but was particularly abundant on opossums. Additionally, Orchopeas howardi (Baker) (Siphonaptera: Ceratophyllidae) was collected from raccoons, and O. howardi and Xenopsylla cheopis (Rothschild) (Siphonaptera: Pulicidae) from opossums. Only raccoons were infested with raccoon lice, and only cats were infested with cat lice. Primarily opossums were infested with mites. Ectoparasite community composition varied by habitat, host species, and season; seasonal variation in ectoparasite communities differed between the sylvatic and urban habitats. While urban mesomammals did not appear to play an important role in supporting tick populations in an urban habitat, urban opossums appear to serve as an alternate host for large numbers of cat fleas, which may be an important consideration for treatment and control efforts against ectoparasites of companion animals.

Determination of the Discriminating Concentration Towards Permethrin for Surveying Resistance in Amblyomma americanum.

Amblyomma americanum Linnaeus (Ixodida: Ixodidae) is ubiquitously present throughout the southeastern United States and is capable of vectoring several pathogens. White-tailed deer are the main host for adult A. americanum. However, this tick species is a generalist that will feed on most vertebrates, including humans, deer, livestock, and pets. Management of this species can be challenging due to a lack of cost-effective strategies. Acaricides are often utilized, however, this may lead to pesticide resistance. The Food and Agriculture Organization of the United Nations (FAO) larval packet test (LPT) was performed on susceptible A. americanum to determine the lethal concentration (LC) and discriminating concentration (DC) values for permethrin. The FAO LPT was used at these pre-established values to compare levels of resistance in ticks collected from a captive deer farm and wild areas representing high and low permethrin exposure settings, respectively. Resistance ratios (RR) calculated from the LC values for the ticks collected from farmed and wild deer ranged between 1 and 2. A. americanum collected from farmed and wild deer were not found to be resistant, however, some samples had slightly elevated RRs as compared to the susceptible laboratory strain, which may suggest tolerance development. Although the A. americanum sampled in this study were not resistant to permethrin, the DC calculated in this study will allow for rapid evaluation of resistance in a permethrin resistance monitoring program such that alternate management strategies can be adopted if resistance is detected.

Nucleosome assembly: the CAF and the HAT.

Recent data argue strongly that a protein complex termed chromatin assembly factor-1 (CAF-I) plays a major role in de novo nucleosome assembly during DNA replication. Human CAF-I deposits newly synthesized, acetylated histones onto replicated DNA in vitro and localizes to sites of DNA replication in S-phase cells. Specific lysines of the histones used for nucleosome assembly are acetylated; in the past year the first gene encoding a histone acetyltransferase was cloned. However, mechanistic links between histone acetylation and nucleosome assembly have not been established in vivo or in vitro.

The impact of sharing results of a randomized breast cancer clinical trial with study participants.

BACKGROUND: There has been growing interest in providing clinical trial participants with study results yet only limited information exists regarding the process and impact of sharing results. We sought to evaluate patient perceptions of how results had been shared from a large randomized cooperative group trial, and the impact of learning results. PATIENTS AND METHODS: A subset of women who participated in NCCTG 9831 (A Phase III Trial of Adjuvant Chemotherapy with or without Trastuzumab for Women with HER2-positive Breast Cancer) were mailed surveys after the preliminary study results were released to the public and mailed to participants. RESULTS: One hundred and 67 of 228 surveys sent (73%) were returned; 61% reported receiving trastuzumab on study; 4% reported recurrent disease. Ninety-five percent of participants were glad they received results; 81% were satisfied with how results were shared; 23% were more anxious after learning the results. Sixty-nine percent correctly interpreted the results. Logistic regression revealed that satisfaction with the process of receiving results was associated with satisfaction with treatment (P = 0.04), and increased anxiety was associated with dissatisfaction with treatment (0.02), incorrect interpretation of results (0.04), and not having received trastuzumab (P < 0.0001). CONCLUSION: Sharing results directly with study participants is met with overwhelmingly favorable responses from patients, although some may not initially understand the findings. The potential for increased anxiety should be considered, and psychosocial support may be required by some. A plan to share results should be routinely and prospectively considered in the design of cancer clinical trials.

Host-seeking height preferences of Aedes albopictus (Diptera: Culicidae) in north central Florida suburban and sylvatic locales.

The response of Aedes albopictus to the BG-Sentinel, Omni-directional-Fay-Prince, and Mosquito MagnetX traps was evaluated in four suburban and four sylvatic habitats in north-central Florida to ascertain potential height preference of this species. These traps, which are primarily designed to attract diurnal mosquitoes, were set at 1 and 6 m and were evaluated during 40 trapping periods over 4 mo. We collected 45,640 mosquitoes, representing 26 species from 10 genera, the most common being Aedes albopictus, Ae. vexans, Coquilletidia perturbans, Culex nigripalpus, Aedes infirmatus, Ae. triseriatus, and Psorophora ferox. Although significantly more Ae. albopictus were captured at 1 m above ground than at 6 m, fewer were captured in sylvatic habitats than suburban habitats. Although not statistically different, the BG-Sentinel caught more Ae. albopictus compared with the other two traps regardless of locale. These results suggest that, although Ae. albopictus was captured as high as 6 m, the majority seek hosts at or below 1-m heights. This further supports prior research that, although Ae. albopictus has been shown to disseminate West Nile virus, it has not been implicated as a major vector for the virus, which is likely because of its propensity to feed on ground-dwelling hosts. The study also shows how trap type, trap heights, and environments influence sampling estimates when determining species abundance.

Infusion-baited ovitraps to survey ovipositional height preferences of container-inhabiting mosquitoes in two Florida habitats.

To ascertain mosquito species-specific oviposition height preferences, a study was conducted evaluating the response of field populations of container-inhabiting mosquitoes to water, oak (Quercus spp.),or oak-pine (Pinus spp.) infusion-baited ovitraps in four suburban and four sylvatic habitats in north central Florida. In total, 48 ovitraps, 24 suspended at each height of 1 or 6 m (near the ground or tree canopy, respectively), were monitored weekly for 5 mo. Throughout our study, we collected 13,276 mosquito eggs, representing five species from four genera, the most common being Aedes triseriatus (Say), Aedes albopictus Skuse, and Orthopodomyia signifera (Coquillett). Significantly more Ae. triseriatus and Ae. albopictus eggs were oviposited in containers with oak and oak-pine infusions compared with water alone. Significantly more Ae. albopictus eggs were recovered from traps at 1 m in suburban habitats, whereas more Ae. triseriatus eggs were recovered at 6 m in sylvatic habitats.

Phase II multicenter study of larotaxel (XRP9881), a novel taxoid, in patients with metastatic breast cancer who previously received taxane-based therapy.

BACKGROUND: Treatment options are limited for patients with refractory metastatic breast cancer (MBC). Larotaxel (XRP9881) is a novel taxoid with preclinical activity against taxane-resistant breast cancer. The current phase II trial of larotaxel was conducted in women with taxane-treated MBC. PATIENTS AND METHODS: Patients were stratified by response to prior taxane therapy (resistant or nonresistant). Larotaxel 90 mg/m(2) was administered as a 1-h infusion every 3 weeks. Patients were evaluated for tumor response every two cycles. A blinded external response review committee determined the overall response rate (ORR), duration of response (DOR), and time to progression (TtP) of the disease. Median survival time (MST) and safety were also evaluated. RESULTS: One hundred and thirty patients were treated. In the nonresistant group, the ORR was 42%; median DOR 5.3 months; median TtP 5.4 months; and MST 22.6 months. In the resistant group, the ORR was 19%; median DOR 5.0 months; median TtP 1.6 months; and MST 9.8 months. The most common grade 3/4 adverse events were neutropenia (82%), fatigue (15%), diarrhea (12%), febrile neutropenia (9%), neutropenic infection (8%), and sensory neuropathy (7%). CONCLUSIONS: Larotaxel has good activity, manageable toxicity, and a favorable therapeutic index in women with taxane-pretreated MBC.

Assembly of nucleosomes: do multiple assembly factors mean multiple mechanisms?

In eukaryotic cells, transcription and DNA replication occur on DNA templates associated with chromatin proteins, most notably histone octamers. Protein factors that can assemble these units have been isolated from many sources. In particular, one factor from human cells is associated with ongoing DNA synthesis; other known assembly factors are not obligately coupled to the replication process. The wide variety of histone chaperones suggests that multiple pathways for the remodeling of chromatin structure have evolved.

Evaluation of two commercial traps for the collection of Culicoides (Diptera: Ceratopogonidae).

Two types of commercial propane-powered traps, mosquito magnet (MM) (American Biophysics Corporation) MM-Freedom (Freedom) and MM-Liberty Plus (Liberty Plus), were evaluated for the collection of Culicoides. Trap preference and seasonal characteristics for the 3 major species, Culicoides furens, Culicoides barbosai, and Culicoides mississippiensis, were recorded from July 7, 2005, to July 24, 2006. Over 35 million Culicoides were captured during our study. When species were evaluated separately, analysis of overall mean trap collections yielded 5 months (February, March, June, September, and October) with significant trap effects. The Freedom trap captured more C. furens in June and October; the Liberty Plus trap captured more C. mississippiensis in February, March, and April, and more C. barbosai in September. The high numbers of Culicoides captured during our study suggest that the number of host-seeking Culicoides could potentially be reduced by continuous trapping during times when they are prevalent. Results of these investigations will be used to guide future control efforts.

Mosquitoes (Diptera: Culicidae) Collected From Residential Yards and Dog Kennels in Florida Using Two Aspirators, a Sweep Net, or a CDC Trap.

Mosquito surveillance typically uses Centers for Disease Control and Prevention (CDC) mosquito light traps baited with CO2. From January 2013 to March 2015, we sampled seven field sites using three active mosquito-trapping techniques (two different aspirators and a sweep net) and the stationary CO2-baited CDC mosquito light trap to determine mosquito capture efficacy for each technique. Sampling occurred in four suburban backyards and three dog kennel facilities near Gainesville, FL, USA; species collection and relative abundance were measured. A total of 32 species and 70,090 individual mosquitoes were collected, including a new record for Alachua County, Florida, Aedes hendersoni (Cockerell). The dominant (>5% of total capture) mosquito species collected during the study included Aedes atlanticus (Dyar and Knab), Aedes infirmatus (Dyar and Knab), Anopheles crucians Wiedemann, Culiseta melanura (Coquillett), Culex erraticus (Dyar and Knab), Culex nigripalpus Theobald, and Uranotaenia sapphirina (Osten Sacken). The CDC trap captured the most species (29), followed by large aspirator (28), small aspirator (26), and the sweep net (23). All dominant species were captured with each sampling technique. Excluding Wyeomyia mitchellii (Theobald), all subdominant species (1-5% of total capture) were collected with each sampling technique. Future sampling should consider the utility (e.g., large numbers are readily collected) and limitations (e.g., personnel requirements) of aspirator collections when designing field-based mosquito sampling projects, especially those in residential areas or those focused upon species captured.

Nucleosomal DNA regulates the core-histone-binding subunit of the human Hat1 acetyltransferase.

BACKGROUND: In eukaryotic cells, newly synthesized histone H4 is acetylated at lysines 5 and 12, a transient modification erased by deacetylases shortly after deposition of histones into chromosomes. Genetic studies in Saccharomyces cerevisiae revealed that acetylation of newly synthesized histones H3 and H4 is likely to be important for maintaining cell viability; the precise biochemical function of this acetylation is not known, however. The identification of enzymes mediating site-specific acetylation of H4 at Lys5 and Lys12 may help explain the function of the acetylation of newly synthesized histones. RESULTS: A cDNA encoding the catalytic subunit of the human Hat1 acetyltransferase was cloned and, using specific antibodies, the Hat1 holoenzyme was purified from human 293 cells. The human enzyme acetylates soluble but not nucleosomal H4 at Lys5 and Lys12 and acetylates histone H2A at Lys5. Unexpectedly, we found Hat1 in the nucleus of S-phase cells. Like its yeast counterpart, the human holoenzyme consists of two subunits: a catalytic subunit, Hat1, and a subunit that binds core histones, p46, which greatly stimulates the acetyltransferase activity of Hat1. Both p46 and the highly related p48 polypeptide (the small subunit of human chromatin assembly factor 1; CAF-1) bind directly to helix 1 of histone H4, a region that is not accessible when H4 is in chromatin. CONCLUSIONS: We suggest that p46 and p48 are core-histone-binding subunits that target chromatin assembly factors, chromatin remodeling factors, histone acetyltransferases and histone deacetylases to their histone substrates in a manner that is regulated by nucleosomal DNA.

Yeast histone deposition protein Asf1p requires Hir proteins and PCNA for heterochromatic silencing.

BACKGROUND: Position-dependent gene silencing in yeast involves many factors, including the four HIR genes and nucleosome assembly proteins Asf1p and chromatin assembly factor I (CAF-I, encoded by the CAC1-3 genes). Both cac Delta asfl Delta and cac Delta hir Delta double mutants display synergistic reductions in heterochromatic gene silencing. However, the relationship between the contributions of HIR genes and ASF1 to silencing has not previously been explored. RESULTS: Our biochemical and genetic studies of yeast Asf1p revealed links to Hir protein function. In vitro, an active histone deposition complex was formed from recombinant yeast Asf1p and histones H3 and H4 that lack a newly synthesized acetylation pattern. This Asf1p/H3/H4 complex generated micrococcal nuclease--resistant DNA in the absence of DNA replication and stimulated nucleosome assembly activity by recombinant yeast CAF-I during DNA synthesis. Also, Asf1p bound to the Hir1p and Hir2p proteins in vitro and in cell extracts. In vivo, the HIR1 and ASF1 genes contributed to silencing the heterochromatic HML locus via the same genetic pathway. Deletion of either HIR1 or ASF1 eliminated telomeric gene silencing in combination with pol30--8, encoding an altered form of the DNA polymerase processivity factor PCNA that prevents CAF-I from contributing to silencing. Conversely, other pol30 alleles prevented Asf1/Hir proteins from contributing to silencing. CONCLUSIONS: Yeast CAF-I and Asf1p cooperate to form nucleosomes in vitro. In vivo, Asf1p and Hir proteins physically interact and together promote heterochromatic gene silencing in a manner requiring PCNA. This Asf1/Hir silencing pathway functionally overlaps with CAF-I activity.

Nuclear expression of the 50- and 65-kD Rel-related subunits of nuclear factor-kappa B is differentially regulated in human monocytic cells.

The nuclear factor (NF)-kappa B transcription factor system is composed of at least four inducible nucleoprotein adducts termed p50, p55 (NF-kappa B p50), p75 (NF-kappa B p65), and p85 (c-Rel). These proteins are expressed in the nuclei of activated T cells in a distinctly biphasic fashion, with p55 and p75 induction occurring within minutes whereas the induction of p50 and p85 occurs after several hours. In contrast, p50 and p55 are constitutively expressed in the nuclei of U937 and THP-1 monocytic cells. However, cellular activation is required for the nuclear expression of p75 in these cells. Additionally, activation of monocytic cells does not result in a significant induction of p85. Tumor necrosis factor alpha induces the nuclear expression of p55 and p75 in these monocytic cells within 20 min, presumably reflecting the liberation of these proteins from I kappa B. In contrast, phorbol myristate acetate (PMA) induces the expression of these proteins with delayed kinetics, raising the possibility that PMA is incapable of mediating the efficient release of p55 and p75 from I kappa B in these cells. These findings highlight important differences in the regulation of these proteins in monocytic cells versus T cells and suggest that the induced expression of NF-kappa B p65 in monocytes may play a central role in the activation of HIV-1 gene expression.