Investigating incursions of bluetongue virus using a model of long-distance Culicoides biting midge dispersal

Bluetongue virus (BTV) is an economically important pathogen of ruminants that is the aetiological agent of the haemorrhagic disease bluetongue. Bluetongue virus is biologically transmitted by Culicoides biting midges (Diptera: Ceratopogonidae), and long-range dispersal of infected vector species contributes substantially to the rapid spread of the virus. The range of semi-passive flights of infected Culicoides on prevailing winds has been inferred to reach several hundred kilometres in a single night over water bodies. In this study, an atmospheric dispersion model was parameterized to simulate Culicoides flight activity based on dedicated entomological data sets collected in the UK. Five outbreaks of BTV in Europe were used to evaluate the model for use as an early warning tool and for retrospective analyses of BTV incursions. In each case, the generated predictions were consistent with epidemiological observations confirming its reliability for use in disease outbreak management. Furthermore, the model aided policy makers to predict, contain and eradicate BTV outbreaks in the UK during 2007 and 2008.

Impacts of climate, host and landscape factors on Culicoides species in Scotland

Culicoides biting midges (Diptera: Ceratopogonidae) vector a wide variety of internationally important arboviral pathogens of livestock and represent a widespread biting nuisance. This study investigated the influence of landscape, host and remotely-sensed climate factors on local abundance of livestock-associated species in Scotland, within a hierarchical generalized linear model framework. The Culicoides obsoletus group and the Culicoides pulicaris group accounted for 56% and 41%, respectively, of adult females trapped. Culicoides impunctatus Goetghebuer and C. pulicaris s.s. Linnaeus were the most abundant and widespread species in the C. pulicaris group (accounting for 29% and 10%, respectively, of females trapped). Abundance models performed well for C. impunctatus, Culicoides deltus Edwards and Culicoides punctatus Meigen (adjusted R(2) : 0.59-0.70), but not for C. pulicaris s.s. (adjusted R(2) : 0.36) and the C. obsoletus group (adjusted R(2) : 0.08). Local-scale abundance patterns were best explained by models combining host, landscape and climate factors. The abundance of C. impunctatus was negatively associated with cattle density, but positively associated with pasture cover, consistent with this species' preference in the larval stage for lightly grazed, wet rush pasture. Predicted abundances of this species varied widely among farms even over short distances (less than a few km). Modelling approaches that may facilitate the more accurate prediction of local abundance patterns for a wider range of Culicoides species are discussed.

A novel type of familial proximal axonal dystrophy: three cases and a review of the axonal dystrophies

Three related infants of Roma ancestry, two of them siblings, showed hypotonia, predominantly axial, from birth, difficulty swallowing, myoclonic seizures, and respiratory difficulty. Dysmorphic features, principally micrognathia were present. EEGs showed focal epileptiform abnormalities. All three died in their 5th month from respiratory insufficiency complicated by pneumonia. Autopsy showed small brains without malformation. Microscopy revealed numerous axonal spheroids involving particularly the brain stem and spinal cord, with especial prominence in the middle cerebellar peduncle, the anterior part of the thalamic reticular nuclei, and the anterior horns and columns of the spinal cord. Spheroids that appeared to be on axons of lower motor neurons were especially large. No spheroids were seen in peripheral nerves; electron microscopy did not show spheroids in skin. By electron microscopy spheroids contained neurofilaments, sparse mitochondria, and electron dense granules. The material did not allow identification of microtubules. Closely packed vesicles excluded neurofilamanets from the center of many spheroids, especially in the middle cerebellar peduncle. Sprouting of axons from the surface of many spheroids was seen. This disease is distinct from the well described type of infantile neuroaxonal dystrophy (Seitelberger's disease) in view of the distribution of spheroids, presence of spheroids on proximal rather than distal parts of axons, sparing of the peripheral nerves, lack of staining for synuclein, presence of sprouting, and lack of membranous profiles in the spheroids. A review of reported types of axonal dystrophy has not shown identical cases.

Current prescription of prophylactic factor infusions and perceived adherence for children and adolescents with haemophilia: a survey of haemophilia healthcare professionals in the United States

The primary goal of prophylaxis in patients with severe haemophilia is to convert the phenotype from severe to moderate and to prevent the development of chronic arthropathy. Prior studies have demonstrated that prophylaxis decreases episodes of joint bleeds and chronic arthropathy. Effectiveness depends on prescription of prophylaxis and adherence to the prescribed regimen. The aim of this study was to determine if prescription of prophylaxis for children with haemophilia and perceptions of adherence to prophylaxis have changed since publication of the Joint Outcome Study (JOS). A questionnaire was sent, in electronic and written formats, to health professionals who provide care to children with haemophilia at US haemophilia treatment centres (HTCs). The response rate was 56 of 128 (44%) of the targeted HTCs. There were a few missing data and denominators are provided. All responses agreed with the results of the JOS and 30/55 (55%) reported the JOS increased their prescription of prophylaxis. Nineteen of 56 (34%) physicians or HTC staff reported that they had not prescribed prophylaxis within the last year due to concerns about adherence, and 19/56 (34%) reported they had stopped prophylaxis due to concerns about adherence within the last year. Predicted adherence decreased with increasing age. Prescription of prophylaxis appears to be increasing since publication of the JOS. Strategies to improve adherence may increase the likelihood of physician prescription of prophylaxis and make prophylaxis easier to implement for individual patients, thereby improving the clinical outcome of children and adults with haemophilia.

Collection of Culicoides (Diptera: Ceratopogonidae) using CO2 and enantiomers of 1-octen-3-ol in the United Kingdom

The host kairomones carbon dioxide (CO2) and 1-octen-3-ol elicit a host seeking response in a wide range of haematophagous Diptera. This study investigates the response of Culicoides biting midges (Diptera: Ceratopogonidae) to these cues using field-based experiments at two sites in the United Kingdom with very different species complements. Traps used for surveillance (miniature CDC model 512) and control (Mosquito Magnet Pro) were modified to release ratios of (R)- and (S)-1-octen-3-ol enantiomers in combination with CO2 and, in the case of the latter trap type, a thermal cue. Abundance and species diversity were then compared between these treatments and against collections made using a trap with a CO2 lure only, in a Latin square design. In both habitats, results demonstrated that semiochemical lures containing a high proportion of the (R)-enantiomer consistently attracted a greater abundance of host-seeking Culicoides females than any other treatment. Culicoides collected using an optimal stimulus of 500 ml/min CO2 combined with 4.1 mg/h (R)-1-octen-3-ol were then compared with those collected on sheep through the use of a drop trap. While preliminary in nature, this trial indicated Culicoides species complements are similar between collections made using the drop trap in comparison to the semiochemical-baited CDC trap, and that there are advantages in using (R)-1-octen-3-ol.

Evaluation of matrix-assisted laser desorption/ionization time of flight mass spectrometry for characterization of Culicoides nubeculosus biting midges

Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) has shown promise in species identification of insect species. We evaluated its potential to consistently characterize laboratory-reared biting midges of the species Culicoides nubeculosus (Meigen) (Diptera: Ceratopogonidae). Twenty-one reproducible potential biomarker masses for C. nubeculosus were identified under different experimental treatments. These treatments included the homogenization of insects in either water or known concentrations of formic acid. The biomarker masses were present independent of age, gender and different periods of storage of individuals in 70% ethanol (a standard preservation method). It was found that the presence of blood in females reduced the intensity of the MALDI-TOF pattern, necessitating the removal of the abdomen before analysis. The protein profiles of a related non-biting midge, Forcipomyia sp. (Diptera: Ceratopogonidae), and of Aedes japonicus japonicus (Theobald) (Diptera: Culicidae) mosquitoes were also examined and were distinctly different. These findings provide preliminary data to optimize future studies in differentiation of species within the Culicoides genus using MALDI-TOF MS which is a rapid, simple, reliable and cost-effective technique.

Laboratory and field-based tests of deltamethrin insecticides against adult Culicoides biting midges

Bluetongue virus (BTV) is an economically important arbovirus of ruminants transmitted by Culicoides biting midges. Vector control using residual spraying or application to livestock is recommended by many authorities to reduce BTV transmission; however, the impact of these measures in terms of both inflicting mortality on Culicoides and subsequently upon BTV transmission is unclear. This study consisted of a standardized World Health Organization laboratory assay to determine the susceptibility of European Culicoides species to deltamethrin and a field trial based upon allowing individuals of a laboratory strain of Culicoides nubeculosus Meigen to feed upon sheep treated with Butox 7.5 pour-on (a deltamethrin-based topical formulation). Susceptibility in the laboratory trial was higher in colony C. nubeculosus (24-h LC90 = 0.00106%), than in field populations of Culicoides obsoletus Meigen (24-h LC90 = 0.00203%) or Culicoides imicola Kieffer (24-h LC90 = 0.00773%). In the field, the pour-on formulation was tested with a total of 816 C. nubeculosus specimens fed upon on the thigh of treated sheep. The study revealed a maximum mortality rate of 49% at 4 d postapplication, and duration of lethal effect was predicted to be as short as 10 d, despite testing being carried out with a highly susceptible strain. The reasons for this low efficacy are discussed with reference both to the potential for lack of spread of the active ingredient on the host and feeding patterns of the major potential vector species on the sheep host. Practical implications for vector control strategies during BTV incursions are also detailed.

Trimodality treatment for advanced esophageal cancer: Impact of minimally invasive esophagectomy

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Background: Esophageal cancer is best managed by multimodality therapy, frequently with chemotherapy (C) or chemo- radiotherapy (CRT) preceding resection. Minimally invasive esophagectomy (MIE) is increasingly accepted, but studies of MIE in advanced esophageal and gastroesophageal junction cancer after induction CRT are lacking. This report presents the data on MIE as part of tri-modality therapy for esophageal cancer at Mayo Clinic in Arizona (MCA).

Methods: Patients (pts) who underwent CRT before or after MIE for cancer at MCA between November 2006 and May of 2010 were reviewed retrospectively.

Results: 46 pts (40 males, and 6 females) met study criteria and were reviewed. Median age was 62 years (41-88 years). 45 pts (98%) had adenocarcinoma and one pt had squamous carcinoma. Initial clinical stage was IIA in 10 pts (22%), IIB in 3 pts (7%), III in 26 pts (55%), and IVA in 7 pts (15%) with positive celiac nodes. 43 pts (93%) underwent preoperative CRT with additional intra-operative radiotherapy in 4 pts. Median operating time was 354 min (range 211-567 min), median blood loss was 225 ml (range 50-1,400 ml), and median hospital stay was 8 days (range 5-48 days). 19 pts (41%), including the 3 who did not undergo preoperative CRT, received postoperative C or CRT due to either residual disease at resection or to local recurrence. 30 of 43 pts undergoing MIE after CRT were down staged (11 CR [25.6%], 10 near CR [23.3%]) demonstrating a major response to neoadjuvant therapy in 48.9% of pts. One pt died in hospital (from ARDS and sepsis subsequent to aspiration pneumonia) and two pts died within 30 days of surgery (one from pulmonary embolism, and the other from unknown causes) for a 30 day surgical mortality of 6.5%. 29 pts (63%) had a complication of surgery including 11 (24%) minor and 18 (39%) major complications. After a median follow-up of 13 months (range 0.9-43 months) 16 pts were diagnosed with recurrent disease and 10 of these pts have died of their disease.

Conclusions: CRT with MIE is associated with an acceptable morbidity and mortality level for pts with locally advanced esophageal cancer. These results compare favorably with morbidity, mortality, and recurrence rates in open esophagectomy pts.

No significant financial relationships to disclose.

Evaluation of housing as a means to protect cattle from Culicoides biting midges, the vectors of bluetongue virus

The housing of animals at night was investigated as a possible means of protecting them from attack by Culicoides biting midges (Diptera: Ceratopogonidae), the vectors of bluetongue. Light-trap catches of Culicoides were compared inside and outside animal housing, in the presence and absence of cattle. A three-replicate, 4 x 4 Latin square design was used at four farms in Bala, north Wales, over 12 nights in May and June 2007, and the experiment repeated in October. In the two studies, respectively, >70 000 and >4500 Culicoides were trapped, of which 93% and 86%, respectively, were of the Culicoides obsoletus group. Across the four farms, in May and June, the presence of cattle increased catches of C. obsoletus by 2.3 times, and outside traps caught 6.5 times more insects than inside traps. Similar patterns were apparent in October, but the difference between inside and outside catches was reduced. Catches were strongly correlated with minimum temperature and maximum wind speed and these two variables explained a large amount of night-to-night variation in catch. Outside catches were reduced, to a greater extent than inside catches, by colder minimum temperatures and higher maximum wind speeds. These conditions occur more frequently in October than in May and June, thereby suppressing outside catches more than inside catches, and reducing the apparent degree of exophily of C. obsoletus in autumn. The results suggest that the risk of animals receiving bites from C. obsoletus is reduced by housing at both times of year and the benefit would be greatest on warm, still nights when outside catches are at their greatest.

Variant Creutzfeldt-Jakob disease: the first confirmed case from Portugal shows early onset, long duration and unusual pathology

We present clinical and autopsy findings in the first case of variant Creutzfeldt-Jakob disease diagnosed and confirmed in Portugal. Onset was at 11 years, the earliest onset reported, and the course (32 months) relatively long. Western blot showed protease resistant prion protein, mainly of type 4 (2B) isoform. The cerebral cortex revealed severe spongiform change with numerous amyloid plaques, which did not fit the definition of florid plaques. In the striatum, spongiform change was limited but the extracellular space was dilated. Other reports have found marked spongiform change in the striatum and little in the cortex. Massive neuronal loss, in excess of what has been described, was found in the thalamus and pontine grey. The cerebellum showed, as expected, severe loss of granule cells, moderate loss of Purkinje cells and marked immunopositivity for the prion protein. Differences between our findings and previous ones probably result from the patient's long survival.

Susceptibility of Culicoides biting midge larvae to the insect-pathogenic fungus, Metarhizium anisopliae: prospects for bluetongue vector control

Culicoides biting midges (Diptera: Ceratopogonidae) are responsible for the spread of several arboviruses of livestock and humans that are of international importance. This study assesses the virulence of 18 insect-pathogenic fungal strains from the genera Metarhizium, Beauveria, Isaria and Lecanicillium to larval stages of Culicoides nubeculous Meigen as a means of examining their potential as biocontrol agents. In initial screening, six strains of M. anisopliae (ERL700, CA1, V275, LRC181A, ARSEF 3291 and ARSEF 4556) outperformed the other tested genera and were found to cause between 90% and 100% larval mortality in all larval instars of this species at 72 h post inoculation. The virulence of the most effective strain, M. anisopliae V275, was then further tested by exposing larvae to doses which ranged from 10(4)-10(8) conidia/ml and recording mortality at 24, 48 and 72 h in a 24-multi-well plate with each well containing 600 microl of water and at 24 and 48 h in 250 ml plastic cups containing 50 ml of water. Sensitivity of larvae was extremely high in the multi-well plates, with LC(50) values of 4.3-4.5 x 10(3)conidia/ml and no significant differences between larval instars. In the 250 ml cups, M. anisopliae V275 caused mortalities of between 70% and 100% to larvae and later instars exhibited higher mortality rates. The results are discussed in relation to incorporation of M. anisopliae into biocontrol programmes to control arboviruses vectored by Culicoides.

Sporadic Creutzfeldt-Jakob disease causing a 2-years slowly progressive isolated dementia

A 47-year-old woman was seen for progressive behavioural and cognitive disturbances slowly evolving over a 1-year period. Neuropsychological evaluation disclosed moderate to severe impairment of all cortical functions. Besides this no other clinical abnormality was found. MRI diffusion weighted imaging disclosed hyperintense cortical lesions in a ribbon-like fashion, with restricted diffusivity. EEG showed no periodic sharp waves and CSF examination was normal, including protein 14.3.3. She was heterozygote on codon 129. Her cognitive function continued to decline and she was readmitted for further investigation at the 24th month of disease. Again no ataxia or involuntary movements were observed. MRI disclosed widespread hyperintense lesions over the entire cortex and, for the first time, also caudato-putaminal hyperintensity in T2-weighted images. EEG again failed to show periodic activity. Stereotactic biopsy disclosed moderate spongiform changes, astrocytosis and perivacuolar staining with prion-directed antibodies. Western blot analysis revealed prion type 2 mobility pattern. We discuss the clinical significance of this case: as dementia was the sole finding, and this was slowly-evolving over a 2-year period, MRI findings were the key factor suggesting a prion disease in a woman that otherwise would probably be diagnosed with a primary degenerative dementia.

Life-history parameters of Culicoides (Avaritia) imicola Kieffer in the laboratory at different rearing temperatures

This laboratory study investigates the sub-adult developmental cycle of field collected Culicoides (Avaritia) imicola Kieffer (Diptera; Ceratopogonidae). The period required from blood-feeding field-collected females to the production of progeny adults occupied 34-56 days at 20 degrees C, 15-21 days at 25 degrees C and 11-16 days at 28 degrees C, demonstrating clear temperature dependence. When reared at 28 degrees C, C. imicola demonstrated higher variability in fecundity (between 2.4 and 20.6 eggs/female) and lower hatching rates (50.0-62.2%), although larval survival rates to pupation were low at all temperatures (20-30%). Similarly, the mean emergence rate from pupae was the highest at lower temperatures. These results highlight the difficulty in establishing and maintaining a laboratory colony of this species from field-collected material and results are discussed in reference to future research directions that may aid this process.

Efficacy of alphacypermethrin applied to cattle and sheep against the biting midge Culicoides nubeculosus

The recent emergence of bluetongue virus (BTV) in northern Europe, has led to an urgent need to identify methods to control the Culicoides biting midges that transmit it. Here, an in vitro assay was used to assess the effects of the proprietary pyrethroid insecticide alphacypermethrin applied to cattle and sheep (Dysect Cattle Pour-On, Dysect Sheep Pour-On; Ford Dodge Animal Health) against the biting midge Culicoides nubeculosus (Meigen) (Diptera: Ceratopogonidae). Hair or wool was collected from the back, belly and legs of animals immediately prior to treatment and 7, 14, 21, 28 and 35 days after treatment, and also from untreated controls. In the laboratory assay groups of 10 adult females C. nubeculosus were exposed to 0.5 g of hair or wool for 3 min. In all cases, no mortality was observed in the pre-treatment sample or the untreated controls. In the post-treatment samples, for both cattle and sheep mortality was close to 100% 7 days after treatment. For cattle, treatment effect persisted for up to 21 days post-treatment, following which the mortality rate following exposure to hair samples declined. In contrast, for sheep, mortality levels declined more slowly, and approximately 50% mortality was still observed 35 days after treatment. There was no significant difference in the kill rate for wool collected from the back, belly or legs of either sheep or cattle. The results demonstrate the potential for pour-on insecticide treatment to offer a degree of mitigation to livestock against onward transmission from infected animals--and in particular demonstrate that sufficient compound is able to reach the lower legs to kill in contact midges. The practical issues associated with achieving adequate protection are discussed.

Experimental infection studies of UK Culicoides species midges with bluetongue virus serotypes 8 and 9

This paper describes a rapid, standardised method for testing the susceptibility to bluetongue virus (BTV) of northern Palaearctic Culicoides species midges that can be used to assess the competence of both field-caught and laboratory-infected midges. The method has been used to show that Culicoides scoticus can replicate btv serotype 8 and BTV serotype 9 strains to more than 3 log(10) TCID50/midge, the first evidence of the potential of this species to transmit BTV.