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West Nile Virus (west + nile_virus)
Selected AbstractsBiodiversity May Curb West Nile VirusCONSERVATION, Issue 1 2006Article first published online: 8 MAR 200 No abstract is available for this article. [source] Control of arbovirus infections by a coordinated response: West Nile Virus in England and WalesFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 3 2006Dilys Morgan Abstract Although there is no recognized transmission of human arboviral infections in the UK, concerns about the possible spread of West Nile virus (WNV) have precipitated coordinated activities around both surveillance and response. The Department of Health has chaired a UK WNV task force since the end of 2000. This is a multidisciplinary group of senior representatives from Agencies and Government Departments involved in human and animal health, entomology and academic departments. Activities include surveillance for WNV infections in humans, and in dead birds, mosquitoes and horses. All have been negative for WNV. A WNV contingency plan was produced in 2004, and this could be used as a generic plan for an effective and coordinated response in the event of the emergence of a new vector-borne zoonotic infection. [source] Range-wide patterns of greater sage-grouse persistenceDIVERSITY AND DISTRIBUTIONS, Issue 6 2008Cameron L. Aldridge ABSTRACT Aim, Greater sage-grouse (Centrocercus urophasianus), a shrub-steppe obligate species of western North America, currently occupies only half its historical range. Here we examine how broad-scale, long-term trends in landscape condition have affected range contraction. Location, Sagebrush biome of the western USA. Methods, Logistic regression was used to assess persistence and extirpation of greater sage-grouse range based on landscape conditions measured by human population (density and population change), vegetation (percentage of sagebrush habitat), roads (density of and distance to roads), agriculture (cropland, farmland and cattle density), climate (number of severe and extreme droughts) and range periphery. Model predictions were used to identify areas where future extirpations can be expected, while also explaining possible causes of past extirpations. Results, Greater sage-grouse persistence and extirpation were significantly related to sagebrush habitat, cultivated cropland, human population density in 1950, prevalence of severe droughts and historical range periphery. Extirpation of sage-grouse was most likely in areas having at least four persons per square kilometre in 1950, 25% cultivated cropland in 2002 or the presence of three or more severe droughts per decade. In contrast, persistence of sage-grouse was expected when at least 30 km from historical range edge and in habitats containing at least 25% sagebrush cover within 30 km. Extirpation was most often explained (35%) by the combined effects of peripherality (within 30 km of range edge) and lack of sagebrush cover (less than 25% within 30 km). Based on patterns of prior extirpation and model predictions, we predict that 29% of remaining range may be at risk. Main Conclusions, Spatial patterns in greater sage-grouse range contraction can be explained by widely available landscape variables that describe patterns of remaining sagebrush habitat and loss due to cultivation, climatic trends, human population growth and peripherality of populations. However, future range loss may relate less to historical mechanisms and more to recent changes in land use and habitat condition, including energy developments and invasions by non-native species such as cheatgrass (Bromus tectorum) and West Nile virus. In conjunction with local measures of population performance, landscape-scale predictions of future range loss may be useful for prioritizing management and protection. Our results suggest that initial conservation efforts should focus on maintaining large expanses of sagebrush habitat, enhancing quality of existing habitats, and increasing habitat connectivity. [source] Synergistic impacts of malathion and predatory stress on six species of North American tadpolesENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2004Rick A. Relyea Abstract The decline of many amphibian populations is associated with pesticides, but for most pesticides we know little about their toxicity to amphibians. Malathion is a classic example; it is sprayed over aquatic habitats to control mosquitoes that carry malaria and the West Nile virus, yet we know little about its effect on amphibians. I examined the survival of six species of tadpoles (wood frogs, Rana sylvatica; leopard frogs, R. pipiens; green frogs, R. clamitans; bullfrogs, R. catesbeiana; American toads, Bufo americanus; and gray tree frogs, Hyla versicolor) for 16 d in the presence or absence of predatory stress and six concentrations of malathion. Malathion was moderately toxic to all species of tadpoles (median lethal concentration [LC50] values, the concentration estimated to kill 50% of a test population, ranged from 1.25,5.9 mg/L). These values are within the range of values reported for the few amphibians that have been tested (0.2,42 mg/L). In one of the six species, malathion became twice as lethal when combined with predatory stress. Similar synergistic interactions have been found with the insecticide carbaryl, suggesting that the synergy may occur in many carbamate and organophosphate insecticides. While malathion has the potential to kill amphibians and its presence is correlated with habitats containing declining populations, its actual role in amphibian declines is uncertain given the relatively low concentration in aquatic habitats. [source] Altered effector functions of virus-specific and virus cross-reactive CD8+ T cells in mice immunized with related flavivirusesEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 5 2010Derek W. Trobaugh Abstract Memory cross-reactive CD8+ T-cell responses may induce protection or immunopathology upon secondary viral challenge. To elucidate the potential role of T cells in sequential flavivirus infection, we characterized cross-reactive CD4+ and CD8+ T-cell responses between attenuated and pathogenic Japanese encephalitis virus (JEV) and pathogenic West Nile virus (WNV). A previously reported WNV NS4b CD8+ T-cell epitope and its JEV variant elicited CD8+ T-cell responses in both JEV- and WNV-infected mice. The peptide variant homologous to the immunizing virus induced greater cytokine secretion and activated higher frequencies of epitope-specific CD8+ T cells. However, there was a virus-dependent, peptide variant-independent pattern of cytokine secretion; the IFN,+ -to-IFN,+TNF,+ CD8+ T-cell ratio was greater in JEV- than in WNV-infected mice. Despite similarities in viral burden for pathogenic WNV and JEV viruses, CD8+ T cells from pathogenic JEV-immunized mice exhibited functional and phenotypic profiles similar to those seen for the attenuated JEV strain. Patterns of killer cell lectin-like receptor G1 (KLRG1) and CD127 expression differed by virus type, with a rapid expansion and contraction of short-lived effector cells in JEV infection and persistence of high levels of short-lived effector cells in WNV infection. Such cross-reactive T-cell responses to primary infection may affect the outcomes of sequential flavivirus infections. [source] Control of arbovirus infections by a coordinated response: West Nile Virus in England and WalesFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 3 2006Dilys Morgan Abstract Although there is no recognized transmission of human arboviral infections in the UK, concerns about the possible spread of West Nile virus (WNV) have precipitated coordinated activities around both surveillance and response. The Department of Health has chaired a UK WNV task force since the end of 2000. This is a multidisciplinary group of senior representatives from Agencies and Government Departments involved in human and animal health, entomology and academic departments. Activities include surveillance for WNV infections in humans, and in dead birds, mosquitoes and horses. All have been negative for WNV. A WNV contingency plan was produced in 2004, and this could be used as a generic plan for an effective and coordinated response in the event of the emergence of a new vector-borne zoonotic infection. [source] Interleukin-29 uses a type 1 interferon-like program to promote antiviral responses in human hepatocytes,HEPATOLOGY, Issue 4 2006Sean E. Doyle Interleukin-28A (IL-28A), IL-28B and IL-29 are a family of class II cytokines that stimulate antiviral responses through a heterodimeric receptor that is distinct from the type I interferon (IFN) receptor. To better understand how this newly described family of cytokines regulates the antiviral state, we compared various cellular responses elicited by IL-29 and IFN-,. Here we show that these cytokines stimulate similar patterns of signal transducer and activator of transcription 1 (STAT-1), -2, -3, and -5 phosphorylation and nearly identical patterns of gene expression when analyzed in two distinct cell types by microarray analysis. Interestingly, the IL-29 receptor is preferentially expressed on primary hepatocytes within normal liver and pegylated forms of IL-29 and IFN-, induced equivalent 2,5, oligoadenylate synthetase (OAS) and MX1 gene expression in this cell type. Pegylated IL-29 also produced a significant reduction in human hepatitis B and hepatitis C viral load in vitro and reduced the cytopathic effect caused by the fully replicating flavivirus, West Nile virus. In conclusion, IL-29 and IFN-, stimulate identical antiviral responses despite their utilization of different receptors. This fact, combined with significant receptor expression in hepatitis virus-infected livers, suggests that IL-29 may have therapeutic value against chronic viral hepatitis in human patients. (HEPATOLOGY 2006;44:896,906.) [source] The role of zoos in biosurveillanceINTERNATIONAL ZOO YEARBOOK, Issue 1 2007T. McNAMARA Zoos are ideally placed to act as epidemiological monitoring stations because for decades, many have been building up detailed collections of serum banks, tissue banks and medical record-keeping systems that could be mined for information that would be beneficial to public health. For example, in 1999 wild Crows Corvus brachyrhynchos in the United States of America started to die of unknown causes but it was not until some died in the grounds of a zoological institution that West Nile virus, which is a threat to both human and animal health, was identified. There is a serious disparity in the type and amount of biosurveillance provided for humans, agricultural livestock and wildlife agencies, often driven by economic factors. There is an argument for public-health entities to contribute funds to the cost of managing serum-banks and testing stations within zoos to enhance biosurveillance in urban settings, in a cost-effective and mutually beneficial manner. The key to sustainable and integrated biosurveillance lies in public-health professionals working with zoo professionals, who care for wild animals on a day-to-day basis, to create electronic surveillance networks. This could be of utmost benefit to everyone. [source] Climate change and vector-borne viral diseases potentially transmitted by transfusionISBT SCIENCE SERIES: THE INTERNATIONAL JOURNAL OF INTRACELLULAR TRANSPORT, Issue 1 2009M. Rios Vector-borne diseases occur when infectious agents (virus, protozoa, bacteria, or helminthes) are transmitted to their hosts by a carrier organism. Climate conditions and their changes play a role in the inter-relationship between these agents, the vectors and the host (or hosts). This review is focused on arthropod-borne viruses (Arboviruses). These viruses are transmitted between susceptible vertebrate hosts by blood-feeding arthropods, and may be transmitted by blood transfusion, tissue and organ transplantation and breast feeding. The lifecycle of arboviruses is influenced by changes in temperature, rainfall, humidity, length of day, average daily solar radiation and/or storm patterns, as well as changes in the frequency of rare events such as floods or droughts. A plethora of studies have suggested that climate changes, particularly temperature changes, are likely to be induced by increase in the amount of greenhouse gases, such as methane, carbon dioxide (CO2) and chlorofluorocarbons, which deplete ozone in the atmosphere leading to an increase in ultraviolet radiation. Current models predict that ambient temperature will increase by 3,5°C on average with a doubling in CO2 concentration in the atmosphere. Vectors, pathogens and hosts each survive and reproduce within a range of optimal climatic conditions: temperature and precipitation being most important, while sea level elevation, wind and daylight duration are also important. Climate changes may affect important determinants of vector-borne disease transmission including (i) vector survival and reproduction, (ii) the vector's biting rate, and (iii) the pathogen's incubation rate within the vector organism. Droughts can increase the dissemination of arboviral diseases in urban areas by allowing a boost in the population of mosquitoes in foul water concentrated in catch basins where they breed. Furthermore, eggs can be vertically infected with arboviruses and heat waves speed up the maturation of the mosquitoes and of the viruses within mosquitoes. Droughts also cause a decline in mosquito predators like frogs, darning needles and dragonflies. In addition, birds congregate around shrinking water sites, enhancing circulation of viruses among birds and mosquitoes. In conclusion, the seriousness of some of the recent epidemics like West Nile virus and Dengue appear to has been influenced by climate change. As most of the arboviral infections are asymptomatic in humans, there is an increased opportunity for blood, organ and tissue donations by infected individuals during the viraemic period, resulting in an increased risk of transmission of arboviruses. [source] Comparison between the clinical and laboratory features of enterovirus and West Nile virus infectionsJOURNAL OF MEDICAL VIROLOGY, Issue 7 2008Joanna Middleton Abstract The seasonality and clinical features of enterovirus (EV) infections overlap with those of West Nile virus (WNV). The purpose of this study was to determine the frequency of EV detection in patients being tested for WNV and to look for features that could be used to distinguish between infections with these two viruses. Nucleic acid amplification testing (NAT) for EV was performed on all plasma samples submitted for WNV testing in 2003 and 2004. Demographics, clinical features, and laboratory results for patients with documented EV viremia were compared with those for patients with confirmed WNV infection (as diagnosed by NAT and/or serology). NAT for EV was positive on 50 of 1,784 serum or plasma samples submitted for WNV testing (2.8%). Clinical information was compared for 45 patients with EV viremia and 214 patients with WNV infection. Patients with EV viremia were younger and less likely to have heart disease or a travel history (P,<,0.05). The EV viremia cases were distributed throughout the whole province while the WNV cases were predominantly in the southern part of the province. Symptoms were remarkably similar, although patients with WNV infection were more likely to have anorexia, dizziness, rash, and cranial nerve palsy (P,<,0.05). There are no consistent differences in the features of WNV infection and enteroviral viremia so diagnostic tests for both viruses should be performed when WNV is present in local mosquitoes. J. Med. Virol. 80: 1252,1259, 2008. © 2008 Wiley-Liss, Inc. [source] Inhibition of west nile virus replication by retrovirus-delivered small interfering RNA in human neuroblastoma cellsJOURNAL OF MEDICAL VIROLOGY, Issue 5 2008Yongbo Yang Abstract West Nile virus (WNV) has been responsible for the largest outbreaks of arboviral encephalitis in U.S. history. No specific drug is currently available for the effective treatment of WNV infection. To exploit RNA interference as a potential therapeutic approach, a Moloney murine leukemia virus-based retrovirus vector was used to effectively deliver WNV-specific small interfering RNA (siRNA) into human neuroblastoma HTB-11 cells. Viral plaque assays demonstrated that transduced cells were significantly refractory to WNV replication, as compared to untransduced control cells (P,<,0.05), which correlated with the reduced expression of target viral genes and respective viral proteins. Therefore, retrovirus-mediated delivery of siRNA for gene silencing can be used to study the specific functions of viral genes associated with replication and may have potential therapeutic applications. J. Med. Virol. 80:930,936, 2008. © 2008 Wiley-Liss, Inc. [source] West Nile virus: lessons from the 21st centuryJOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 1 2004DACVECC, DACVIM, Pamela A. Wilkins DVM Abstract Introduction: West Nile virus (WNV) first appeared in the United States in 1999, causing illness and death in birds, horses, and humans. While the initial outbreak of this sometimes deadly viral disease was limited to the northeastern United States, the virus had an inexorable migration across the continental United States over the next 3 years, causing huge losses among the affected species. The purpose of this review is to present currently available information regarding the epi-demiology, diagnosis, treatment, and prevention of WNV infection. Veterinarians, particularly those in an emergency practice, serve as an important source of reliable information regarding this disease for animal owners and the public in general. Data sources: Data sources used for the preparation of this review include computer-based searches of PubMed and Commonwealth Agricultural Bureaux (CAB) abstracts. A search in PubMed using ,West Nile' retrieved 1468 ,hits' or references, while a similar search in CAB abstracts produced 815 references. Additional information was obtained from various meeting proceedings, particularly data presented in abstract form, and from the Centers for Disease Control (CDC) website dedicated to WNV. Human data synthesis: Prior to the mid-1990s, reported large-scale epidemics of WNV infection in humans predominantly presented as acute, mild, febrile disease, sometimes associated with lymphadenopathy and skin rash. The recent large epidemic in the United States, in contrast, has prominently featured encephalitis, particularly among the elderly. Additionally, polio-encephalomyelitis-like complications resulting in long-term neurologic sequelae have been reported. There are many WNV-permissive native avian and mosquito hosts in the Unites States and there appear to be few limitations to the spread of the disease in the United States. It is expected that the virus will be identified in all 48 continental states, Mexico, and Canada by the end of 2003. Veterinary data synthesis: The horse is the animal species most affected by the recent WNV epidemic in the United States, and losses to the equine industry have been large and unprecedented. A United States Department of Agriculture (USDA)-approved vaccine against WNV has been in use in horses since 2001 and appears to be effective in limiting the incidence of disease in well-vaccinated populations. WNV infection has been documented in other species of mammals, including camelids (alpaca/llamas) and dogs, and veterinarians should include WNV as a differential diagnosis for animals presenting with clinical signs consistent with central nervous system infection. A large concern exists for endangered bird populations, particularly birds of prey, whether in zoos or in the wild. [source] West Nile virus may have hitched a ride across the Western United States on Culex tarsalis mosquitoesMOLECULAR ECOLOGY, Issue 8 2010TONY L. GOLDBERG West Nile virus spread rapidly from east to west across North America, despite the north-south migratory flyways of its avian hosts. In this issue, Venkatesan & Rasgon (2010) present new data on the population genetics of Culex tarsalis, the dominant West Nile virus vector in the Western United States, suggesting that patterns of mosquito gene flow may better reflect the virus's expansion from the Midwest to the Pacific than patterns of bird movement. These findings suggest a more significant role for vector dispersal in arboviral range expansion than has previously been appreciated, and they highlight the value of molecular genetic studies of insect vector populations for understanding epidemiology and disease ecology. [source] Development of 10 microsatellite loci for Yellow-billed Magpies (Pica nuttalli) and corvid ecology and West Nile virus studiesMOLECULAR ECOLOGY RESOURCES, Issue 1 2008HOLLY B. ERNEST Abstract We developed 10 polymorphic microsatellite loci for Yellow-billed Magpies (Pica nuttalli). The primers were tested across a population of 57 Central California Yellow-billed Magpies and displayed an average of 3.9 alleles per locus. Forty-one American Crows (Corvus brachyrhynchos) from California were polymorphic for seven of the loci with an average of 2.9 alleles per locus. One additional microsatellite-containing locus displayed diagnostic allele sizes and may be useful to distinguish between the two species. These corvid specific microsatellites will aid ecological studies of the population-level effects of diseases, such as West Nile virus. [source] Flaviviruses in motor neuron diseaseMUSCLE AND NERVE, Issue 1 2005Roger Pamphlett MD Abstract Sporadic motor neuron disease (MND) causes a progressive loss of motor neurons. West Nile virus can attack motor neurons, so we examined whether flavivirus infection could be detected in MND cases. Spinal cord sections from 22 MND cases were stained immunohistochemically with a flavivirus-specific antibody. No staining for flavivirus was seen in any case. Sporadic MND does not appear to arise from a recent infection with a flavivirus. Muscle Nerve, 2005 [source] Public safety aspects of pyrethroid insecticides used in West Nile virus-carrying mosquito control,PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 7 2007Derek W Gammon Abstract West Nile virus is becoming increasingly prevalent in the USA, causing fever, encephalitis, meningitis and many fatalities. Spread of the disease is reduced by controlling the mosquito vectors by a variety of means, including the use of pyrethroid insecticides, which are currently under scrutiny for potential carcinogenic effects in humans. Pyrethrins and resmethrin, a pyrethroid, have been shown to cause tumours in rat and mouse models respectively. However, the tumours appear to be caused by liver enzyme induction and hypertrophy rather than genotoxicity, and the results are therefore unlikely to be applicable to humans. Nonetheless, for resmethrin, the US Environmental Protection Agency (EPA) has concluded that there is a likely risk of carcinogenicity in humans, requiring the manufacturers to provide more detailed data to prove that it can be used safely in vector control. Reproductive toxicity of resmethrin in the rat is also discussed. Copyright © 2007 Society of Chemical Industry [source] West Nile virus neuroinvasive diseaseANNALS OF NEUROLOGY, Issue 3 2006Larry E. Davis MD Since 1999, there have been nearly 20,000 cases of confirmed symptomatic West Nile virus (WNV) infection in the United States, and it is likely that more than 1 million people have been infected by the virus. WNV is now the most common cause of epidemic viral encephalitis in the United States, and it will likely remain an important cause of neurological disease for the foreseeable future. Clinical syndromes produced by WNV infection include asymptomatic infection, West Nile Fever, and West Nile neuroinvasive disease (WNND). WNND includes syndromes of meningitis, encephalitis, and acute flaccid paralysis/poliomyelitis. The clinical, laboratory, and diagnostic features of these syndromes are reviewed here. Many patients with WNND have normal neuroimaging studies, but abnormalities may be present in areas including the basal ganglia, thalamus, cerebellum, and brainstem. Cerebrospinal fluid invariably shows a pleocytosis, with a predominance of neutrophils in up to half the patients. Diagnosis of WNND depends predominantly on demonstration of WNV-specific IgM antibodies in cerebrospinal fluid. Recent studies suggest that some WNV-infected patients have persistent WNV IgM serum and/or cerebrospinal fluid antibody responses, and this may require revision of current serodiagnostic criteria. Although there is no proven therapy for WNND, several vaccines and antiviral therapy with antibodies, antisense oligonucleotides, and interferon preparations are currently undergoing human clinical trials. Recovery from neurological sequelae of WNV infection including cognitive deficits and weakness may be prolonged and incomplete. Ann Neurol 2006;60:286,300 [source] Experimental studies of the role of the little raven (Corvus mellori) in surveillance for West Nile virus in AustraliaAUSTRALIAN VETERINARY JOURNAL, Issue 6 2010J Bingham Objective To study the potential role of an Australian corvid, the little raven (Corvus mellori), in the surveillance for exotic West Nile virus (WNV) in Australia. Method In a series of trials, little ravens were infected with WNV (strain 4132 New York 1999) and Kunjin virus (strain K42886) by the intramuscular route. They were observed for 20 days during which blood and swab samples were taken for virus isolation. Tissue samples were taken from ravens humanely killed during the acute infection period, and at the termination of the trials, for virus isolation, histopathology and immunohistochemistry. Results Ravens infected with WNV became mildly ill, but all recovered and seroconverted. Blood virus titres peaked around 3 to 4 days after inoculation at levels between 103.0 to 107.5 plaque forming units/mL. Virus or viral antigen was detected in spleen, liver, lung, kidney, intestine, testis and ovary by virus isolation and/or immunohistochemistry. WNV was detected in oral and cloacal swabs from 2 to 7 days post inoculation. The molecular and pathogenic characteristics of the inocula were consistent with them being of high virulence, as expected for this isolate. Ravens infected with Kunjin virus developed viraemia and seroconverted, although they did not develop disease. Conclusions Little ravens do not develop severe disease in response to virulent WNV infection and for this reason may not be important sentinel hosts in the event of an outbreak of WNV, as in North America. However, as they have relatively high viraemias, they may be able to support virus cycles. [source] Crystallization and preliminary X-ray diffraction analysis of West Nile virusACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 5 2010Bärbel Kaufmann West Nile virus, a human pathogen, is closely related to other medically important flaviviruses of global impact such as dengue virus. The infectious virus was purified from cell culture using polyethylene glycol (PEG) precipitation and density-gradient centrifugation. Thin amorphously shaped crystals of the lipid-enveloped virus were grown in quartz capillaries equilibrated by vapor diffusion. Crystal diffraction extended at best to a resolution of about 25,Å using synchrotron radiation. A preliminary analysis of the diffraction images indicated that the crystals had unit-cell parameters a , b , 480,Å, , = 120°, suggesting a tight hexagonal packing of one virus particle per unit cell. [source] 1362: Infectious posterior uveitisACTA OPHTHALMOLOGICA, Issue 2010N MARKOMICHELAKIS Several infectious agents (parasites, bacteria, fungi, and viruses) can invade the eye and lead to ocular inflammation. Infectious causes should always be considered and ruled out in all patients with posterior uveitis. Toxoplasma gondii is by far the most common cause of infectious posterior uveitis in all ages, while Toxocara canis infects typically children. Onchocerciasis and other parasitic diseases may also cause posterior uveitis, more commonly in developing countries. Nowadays, old bacterial diseases, tuberculosis and syphilis, emerged as common causes of posterior uveitis. Bartonella henselae and Borrelia burgdorferi are other bacteria that can also cause posterior uveitis. Fungal posterior uveitis usually occurs in immunosuppressed patients or in intravenous drug users. Herpes viruses (HSV, VZV, CMV) are also associated with infectious retinitis, in immunocompromised as well as immunocompetent patients, with quite destructive clinical course. Recently, more viruses (such as West Nile virus, Rift valley fever, dengue fever, and chikungunya) have been recognized as etiologic factors of posterior infectious uveitis. A rapid and accurate diagnosis is of high importance for the successful treatment and visual outcome of infectious uveitis. Techniques and methods, such PCR and detection of specific antibodies in the intraocular fluids (Goldmann-Witmer coefficient), play a key role towards the detection of the pathogen of posterior infectious uveitis. [source] Emerging and poorly known viral inflammatory eye diseasesACTA OPHTHALMOLOGICA, Issue 2009M KHAIRALLAH Arthropod vector borne diseases are among the most important emergent infections. They include a wide variety of bacterial, viral, and parasitic diseases that are transmitted to humans by the bite of mosquito, tick, or other arthropod. Most of them are prevalent in tropical and subtropical areas, but they tend to spread into new regions mainly due to increasing temperatures worldwide, movement of people, increasing human population densities, wider dispersal of competent vectors, and transportation of goods and animals. Numerous arthropod vector borne diseases have been associated with uveitis. Among them, specific viral diseases recently emerged as important causes of uveitis in the developing and developed world. They include West Nile virus (WNV) infection, Rift Valley fever (RVF) , dengue fever (DF), and Chikungunya. These viral diseases have been recently associated with an array of ocular manifestations, including anterior uveitis, retinitis, chorioretinitis, retinal vaculitis, and optic nerve involvement. Proper clinical diagnosis of any of these infectious diseases is based on epidemiological data, history, systemic symptoms and signs, and the pattern of uveitis. The diagnosis is usually confirmed by detection of specific antibody in serum. A systematic ocular examination, showing fairly typical findings, can help establish an early clinical diagnosis of a specific systemic viral infection while serologic testing is pending. Prevention remains the mainstay for control of arthropod vector borne viral diseases. [source] Impact of rituximab-associated B-cell defects on West Nile virus meningoencephalitis in solid organ transplant recipientsCLINICAL TRANSPLANTATION, Issue 2 2010Marilyn E. Levi Levi ME, Quan D, Ho JT, Kleinschmidt-DeMasters BK, Tyler KL, Grazia TJ. Impact of rituximab-associated B-cell defects on West Nile virus meningoencephalitis in solid organ transplant recipients. Clin Transplant 2009 DOI: 10.1111/j.1399-0012.2009.01044.x © 2009 John Wiley & Sons A/S. Abstract:, Evidence suggests that West Nile virus (WNV) neuroinvasive disease occurs more frequently in both solid organ and human stem cell transplant recipients. The effect of concomitant anti-B-cell therapy with rituximab, a CD20+ monoclonal antibody, on WNV infection in this population, however, has not been reported. We describe a case of a patient with alpha-1-antitrypsin deficiency who underwent single lung transplantation in 2005 and was maintained on tacrolimus, cytoxan and prednisone. More recently, she had received two courses of rituximab for recurrent A2,A3 grade rejection with concomitant capillaritis and presented six months later with rapid, fulminant WNV meningoencephalitis. Her diagnosis was made by cerebrospinal fluid (CSF) PCR but serum and CSF WNV IgM and IgG remained negative. She received WNV-specific hyperimmune globulin (Omr-Ig-Am®) through a compassionate protocol. She experienced a rapidly progressive and devastating neurological course despite treatment and died three wk after onset of her symptoms. Autopsy revealed extensive meningoencephalomyelitis. [source] | ||||||||||||||||||||||||||||