Епідеміолоґічно значимі чинники ризику інфікування людей вірусом гарячки Західного Нілу

A previous study has illustrated that the alphaVbeta3 integrin served as the functional receptor for West Nile virus (WNV) entry into cells. Domain III (DIII) of WNV envelope protein (E) was postulated to mediate virus binding to the cellular receptor. In this study, the specificity and affinity binding of WNV E DIII protein to alphaVbeta3 integrin was confirmed with co-immunoprecipitation and receptor competition assay. Binding of WNV E DIII protein to alphaVbeta3 integrin induced the phosphorylation of focal adhesion kinase that is required to mediate ligand-receptor internalization into cells. A novel platform was then developed using the atomic force microscopy to measure this specific binding force between WNV E DIII protein and the cellular receptor, alphaVbeta3 integrin. The single protein pair-interacting force measured was in the range of 45 +/- 5 piconewtons. This interacting force was highly specific as minimal force was measured in the WNV E DIII protein interaction with alphaVbeta5 integrin molecules and heparan sulfate. These experiments provided an insight to quantitate virus-receptor interaction. Force measurement using atomic force microscopy can serve to quantitatively analyze the effect of candidate drugs that modulate virus-host receptor affinity.

To the Editor: West Nile virus (WNV) is a mosquitoborne flavivirus that is widespread in Africa, the Middle East, Asia, and southern Europe, where it causes outbreaks and sporadic cases of the disease. It has become an emergent disease in North America, where it was detected for the first time in 1999 and became epidemic shortly thereafter (1). Although WNV was initially considered to have a minor health effect in the Mediterranean basin, human and equine outbreaks reported in the last decade in different countries (2–5) have made WNV infections a public health concern. The epidemiology of WNV in Europe differs from that in America and has only been associated with nonrecurrent, sporadic outbreaks. The reasons for this difference are controversial; it may be due to environmental factors, reservoirs, or even mosquito vectors. In Spain, neither equine nor human WNV cases have been reported. However, some human serosurveys that used hemagglutination inhibition suggested that WNV or closely related flaviviruses circulated during the 1970s in the Ebro delta and areas in Spain (6,7). The Ebro delta, a wetland in Catalonia, in the northeast of Spain, is a stopping-off point for birds migrating between regions of Africa and Europe where different WNV vectors and reservoirs have been identified. The delta could be considered a high-risk area for WNV and other arthropodborne virus infections. To evaluate WNV seroprevalence in the human population of the Ebro delta, a survey was conducted in 2001. After obtaining informed consent, 992 serum samples were obtained from inhabitants of the area. The population studied was representative of the whole area and was stratified by sex and age. Anti-WNV immunoglobulin G (IgG) antibodies were determined by using an in-house indirect enzyme-linked immunosorbent assay (ELISA), as previously described (8). Results were classified as the sample absorbance/positive control absorbance ratio. Samples showing ratio values >0.2 were tested for WNV IgG and IgM by using an indirect and a μ-chain capture ELISA, respectively (Focus Technologies, Cypress, CA, USA), and an in-house microneutralization test. For the microneutralization test, samples were tested in duplicate and assayed twice. Twofold dilutions (25 μL) of the samples (1:16–1:256 dilutions) were assayed by using 100 TCID50 (50% tissue culture infectious dose) of West Nile Eg-101 reference strain in 96-well tissue culture plates with Vero cells and after 7 days of incubation at 37°C and 5% CO2. Thirty-eight samples showed IgG ratios >0.2 by the in-house ELISA. Of these, 12 showed WNV IgG, and 1 was positive for WNV IgM and IgG, according to the Focus assays. Two samples showed positive neutralizing activity, with titers of 32 and 256. The highest titer was shown by the sample that yielded positive levels of both IgM and IgG in the ELISA, which suggests recent WNV infection. Anti-WNV IgG was more often detected in participants in the 20- to 29-year age group (odds ratio [OR] 4.23, 95% confidence interval [CI] 1.04–16.02, p = 0.03) and in persons who reported frequent mosquito bites (OR 8.62, 95% CI 0.44–169, p = 0.08). IgG-positive persons were equally divided by sex. No significant differences were found between antibody-positive or antibody-negative persons with respect to their profession, place of occupation, current residence, time in current residence, outdoor activities, use of insecticides and repellents, or symptoms related to WNV infection. No symptoms related to WNV infection were reported by the IgM/IgG-positive participant, who was 31 years of age, was born in the area, worked outdoors, and was frequently bitten by mosquitoes. He also reported travel to Cuba 1 year earlier, but he had not been vaccinated against flavivirus, and serologic test results for dengue were negative. The other IgG- and neutralizing antibody–positive participant was 45 years of age and was born and works in the area. He had never traveled abroad or been vaccinated against flavivirus. He reported a 4-day fever of unknown origin during the summer 1 or 2 years before the study. He often fishes in the areas and is frequently bitten by mosquitoes. In conclusion, the study found evidence of recent WNV infections in humans living in the Ebro delta, where previous flavivirus circulation has been suggested by Lozano and Filipe (6). IgG-positive results not confirmed by neutralization could be due to cross-reactive antibodies induced by other flavivirus infections or vaccinations (9,10). The probable WNV infection described was asymptomatic, as occurs in ≈80% of cases. Other WNV infections in the area may have remained undetected, including neuroinvasive cases. Intensified research and surveillance in this area will help determine and refine thresholds for public health interventions.

To the Editor: West Nile virus (WNV) is a single-stranded RNA virus in the family Flaviviridae that is transmitted to humans by mosquitoes. Approximately 80% of WNV infections in humans are asymptomatic, whereas ≈20% of infected persons experience fever, often accompanied by a rash. Less than 1% of infections are manifested as neuroinvasive disease, such as meningoencephalitis, polyradiculoneuritis, and polio-like flaccid paralysis (1). WNV is endemic in Africa, southern Asia, and northern Australia, and only sporadic cases or small epidemics are seen in Europe (2). In 1999, WNV emerged in North America. By 2010, ≈1.8 million persons had become infected, with 12,852 reported cases of meningoencephalitis and 1,308 deaths (2). In Europe, the last notable outbreak of WNV infection occurred in Greece in 2010; 197 persons were infected, and 33 died (3). The Czech Republic, Denmark, France, and the Netherlands reported laboratory-confirmed WNV infections in travelers returning from North America (1). We report a case of WNV meningoencephalitis in a 28-year-old German woman, who sought treatment the emergency department of a hospital in Potsdam, Germany, on September 7, 2011. She had a 3-day history of fever of up to 40°C and mental confusion. Six days before admission, she had returned from a 2-week holiday trip to Ottawa, Ontario, Canada. She had spent most of her time in the city of Ottawa. The patient’s medical history was unremarkable. She was in a reduced general condition because of a severe encephalitic syndrome characterized by somnolence, meningism, fever, and mental confusion. Laboratory investigations revealed leukocytosis with 15.000 leukocytes/µL (reference range 4,400–11,300 leukocytes/µL) and elevated C-reactive protein of 14.8 mg/L (reference <3 mg/L). Cerebrospinal fluid (CSF) analysis on the day of admission showed pleocytosis, 430 cells/µL (72% granulocytes, 27% lymphocytes. and 1% monocytes); elevated levels for total protein, 1,023 mg/L (reference range 150–450 mg/L); an albumin level of 637 mg/L (normal range 0–350 mg/L); and a moderately elevated level of the albumin quotient of 20 (reference range <6.5). The CSF/serum diagrams demonstrated a moderate disturbance of the blood–CSF barrier and a substantial intrathecal IgM synthesis of 27.6% (6.15 mg/L) but no intrathecal IgA or IgG synthesis. Results of magnetic resonance imaging of the brain were unremarkable. No parenchymal lesions were found. Antimicrobial drug therapy was initiated with ceftriaxone and ampicillin. Acyclovir was administered empirically for herpes simplex encephalitis until this diagnosis was excluded. Molecular and serologic testing of serum and CSF samples revealed no acute infection with herpesviruses, enteroviruses, alphaviruses, orthobunyaviruses, and arenaviruses or with mycobacteria, Borrelia spp., Toxoplasma gondii, Chlamydia spp., Leptospira spp., and Mycoplasma pneumoniae. CSF and blood cultures were negative for fungi and bacteria, including mycobacteria. An encephalitic syndrome caused by N-methyl-D-aspartate antibodies was also excluded. On the basis of the patient’s travel history, the clinical symptoms, and the initial laboratory findings, WNV infection was suspected. Indirect immunofluorescence assays and virus neutralization tests (VNT) for WNV and other flaviviruses were performed as described (4). IgM and IgG against WNV were detected in serum and in CSF by indirect immunofluorescence assay with an 8-fold (IgM) and 32-fold (IgG) increase in serum titer from day 4 to day 26 (Table). WNV IgG and WNV IgM titers were higher than the titers of antibodies against the other flaviviruses tested (Table), indicating that the antibodies resulted from a WNV infection. The serologic diagnosis was further substantiated by detection of WNV neutralizing antibodies at day 11 (VNT titer 640). The VNT titer further increased to 2,560 on day 26 after onset of disease. Results of reverse transcription PCR were negative for WNV and members of genus Flavivirus in serum and CSF samples taken 4 days after disease onset. Attempts to isolate WNV from serum and CSF samples in cell culture failed as well. The patient recovered slowly and was discharged from the hospital in Potsdam on September 15, 2011. She was then referred to a neurologic rehabilitation center in Berlin and was discharged from there after 2 months with a characterization of restitutio ad integrum (i.e., full recovery, restoration to original condition). Table Results of indirect immunofluorescence assays performed on serum and CSF samples from patient with suspected WNV infection, Germany, 2011* We report a case of WNV infection imported into Germany that was unambiguously confirmed by laboratory testing. WNV meningoencephalitis was diagnosed on the basis of strict serologic criteria established by the Centers for Disease Control and Prevention (Atlanta, GA, USA) (5). In 2011, 69 clinical cases of WNV infection were reported from the province of Ontario, although no cases in the city of Ottawa were reported (Public Health Agency of Canada; www.eidgis.com/wnvmonitorca). This imported case adds to these cases and suggests that travelers are at risk, even if they visit only Ottawa. Physicians in Germany should be aware of the risk for WNV infection among travelers returning from Canada, especially during late summer.

West Nile fever (WNF) or West Nile disease (WND) is a mosquito-borne viral disease that can affect birds, humans and horses. West Nile virus (WNV) is a member of the genus Flavivirus in the family Flaviviridae. WNV is maintained in a mosquito-bird-mosquito transmission cycle, whereas humans and horses are considered dead-end hosts. In human and horses, symptoms range from unapparent infection to mild febrile illness, meningitis, encephalitis or death. WNV has a wide geographical range that includes portions of Europe, Asia, Africa, Australia (Kunjin virus), and in North, Central and South America. Migratory birds are thought to be primarily responsible for virus dispersal, including reintroduction of WNV from endemic areas into regions that experience sporadic outbreaks (Fields Virology, 2001, Lippincott Williams and Wilkins, Philadelphia, Pennsylvania, USA, 1043-1125). The occurrence of disease in humans and animals along with birds and mosquitoes surveillance for WNV activity demonstrates that the virus range has dramatically expanded including North, Central and South America as well as Europe and countries facing the Mediterranean Basin. WND infection in humans has been reported in Morocco in 1996 (Virologie, 1, 1997, 248), in Tunisia in 2007 (Ann. N. Y. Acad., 951, 2001, 117) (Med. Trop., 61, 2001, 487) and 2003 (Epidémiologie de la fièvre West Nile, 2012, Thèse de doctorat, Université Montpellier II, Sciences et techniques du Langueduc, Montpellier, France), and in Algeria in 1994 (Rev. Sci. Tech., 31, 2012, 829). Outbreaks of equine encephalitis have been also reported in Morocco in 1996 (Bull. OIE, 11, 1996, 867), in 2003 (Emerg. Infect. Dis., 11, 2005, 306) and in 2010 (World Animal Health Information Database. WAHID, 2010). Serological evidence of WNV has been demonstrated in the three countries in many species. The aim of this review was to assess the epidemiological situation of WND in north-west Africa comprising Morocco, Algeria and Tunisia, with an updated literature review based on of human cases and equine outbreaks reports as well as serological studies in these countries.

West Nile disease is a vector-borne disease caused by West Nile virus (WNV), involving mosquitoes as vectors and birds as maintenance hosts. Humans and other mammals can be infected via mosquito bites, developing symptoms ranging from mild fever to severe neurological infection. Due to the worldwide spread of WNV, human infection risk is high in several countries. Nevertheless, there are still several knowledge gaps regarding WNV dynamics. Several aspects of transmission taking place between birds and mosquitoes, such as the length of the infectious period in birds or mosquito biting rates, are still not fully understood, and precise quantitative estimates are still lacking for the European species involved. This lack of knowledge affects the precision of parameter values when modelling the infection, consequently resulting in a potential impairment of the reliability of model simulations and predictions and in a lack of the overall understanding of WNV spread. Further investigations are thus needed to better understand these aspects, but field studies, especially those involving several wild species, such as in the case of WNV, can be challenging. Thus, it becomes crucial to identify which transmission processes most influence the dynamics of WNV. In the present work, we propose a sensitivity analysis to investigate which of the selected epidemiological parameters of WNV have the largest impact on the spread of the infection. Based on a mathematical model simulating WNV spread into the Lombardy region (northern Italy), the basic reproduction number of the infection was estimated and used to quantify infection spread into mosquitoes and birds. Then, we quantified how variations in four epidemiological parameters representing the duration of the infectious period in birds, the mosquito biting rate on birds, and the competence and susceptibility to infection of different bird species might affect WNV transmission. Our study highlights that knowledge gaps in WNV epidemiology affect the precision in several parameters. Although all investigated parameters affected the spread of WNV and the modelling precision, the duration of the infectious period in birds and mosquito biting rate are the most impactful, pointing out the need of focusing future studies on a better estimate of these parameters at first. In addition, our study suggests that a WNV outbreak is very likely to occur in all areas with suitable temperatures, highlighting the wide area where WNV represents a serious risk for public health.

West Nile virus-induced pancreatitis

The first cases in the USA of infection with the mosquito vector-borne West Nile virus (WNV) – an enveloped, single-stranded RNA – occurred in 1999 in New York. Since then, it has moved westward and now affects people in nearly every state, with most annual cases appearing in late summer. Suspected infection can be confirmed by ELISA and reverse transcriptase PCR. The incubation period of WNV prior to the onset of symptoms can be as long as 2 weeks. Three clinical categories of infection have been defined: asymptomatic, West Nile fever (WNF) and West Nile meningoencephalitis. The most common symptoms of WNF are flu-like and include fever, headache, myalgia, malaise, diarrhea, vomiting and fatigue. In less than 1% of cases, individuals develop severe, potentially fatal neurologic disease that has been variously classified as West Nile meningitis, West Nile encephalitis and West Nile poliomyelitis (acute flaccid paralysis). The most commonly reported ocular features of WNV infection are multifocal, bilateral chorioretinal lesions characteristically found in either a scattered or linear pattern. Other features include anterior uveitis, retinal vasculitis, optic neuritis and vitritis; less commonly, nystagmus, abducens nerve palsy, optic disc edema and absence of corneal reflex have been reported. Patients were also reported to present with blurred vision, floaters, redness, visual field defects and diplopia. Ocular symptoms of WNV are generally self limited; however, in some notable cases, reduced visual acuity and field loss may persist. Many of the ocular symptoms of WNV infection are associated with numerous viral, bacterial and parasitic diseases, highlighting the importance of differential diagnosis in confirming WNV infection. The fact that ophthalmic manifestations associated with WNV have only been recognized relatively recently makes the long-term prognosis in patients difficult to predict. However, most patients presenting with chorioretinitis show improvement over time, with visual acuity returning to baseline after a few months. There are currently no approved treatments for WNV, although recombinant vaccines are under development.

Arthropod-borne West Nile virus (WNV) infections are highly prevalent under warm climate conditions. Our systematic review summarizes recent evidence on autochthonous human WNV infections in Europe considering increasing temperatures due to climate changes, and focuses on geographic expansion, reported drivers, and implications for One Health surveillance, diagnostics, and blood safety. The analysis of 27 included studies published since 2015 revealed progressive geographic expansion of autochthonous WNV infections including outbreaks, in several regions supported by phylogenetic data consistent with sustained local circulation. In selected integrated surveillance settings, detection of WNV in mosquito pools and birds preceded detection of human infections. Rising temperatures were the most consistently reported meteorological correlate of WNV infection incidence and were associated with earlier seasonal onset and prolonged transmission. Across surveillance and case-series data, West Nile neuroinvasive disease (WNND) was disproportionately reported among older male individuals, and patients with distinct comorbidities. The over-representation of WNND among reported cases was compatible with under-ascertainment of mild and asymptomatic infections. In conclusion, given increasing incidences of WNV infections in Europe due to climate changes, awareness and preparedness are pivotal and should prioritize integrated surveillance, blood donor screening, andconfirmatory diagnostics with improved serological discrimination in regions with flaviviral co-circulation.

The California Arbovirus Surveillance Program was initiated over 50 years ago to track endemic encephalitides and was enhanced in 2000 to include West Nile virus (WNV) infections in humans, mosquitoes, sentinel chickens, dead birds and horses. This comprehensive statewide program is a function of strong partnerships among the California Department of Public Health (CDPH), the University of California, and local vector control and public health agencies. This manuscript summarizes WNV surveillance data in California since WNV was first detected in 2003 in southern California. From 2003 through 2018, 6,909 human cases of WNV disease, inclusive of 326 deaths, were reported to CDPH, as well as 730 asymptomatic WNV infections identified during screening of blood and organ donors. Of these, 4,073 (59.0%) were reported as West Nile neuroinvasive disease. California’s WNV disease burden comprised 15% of all cases that were reported to the U.S. Centers for Disease Control and Prevention during this time, more than any other state. Additionally, 1,299 equine WNV cases were identified, along with detections of WNV in 23,322 dead birds, 31,695 mosquito pools, and 7,340 sentinel chickens. Annual enzootic detection of WNV typically preceded detection in humans and prompted enhanced intervention to reduce the risk of WNV transmission. Peak WNV activity occurred from July through October in the Central Valley and southern California. Less than five percent of WNV activity occurred in other regions of the state or outside of this time. WNV continues to be a major threat to public and wild avian health in California, particularly in southern California and the Central Valley during summer and early fall months. Local and state public health partners must continue statewide human and mosquito surveillance and facilitate effective mosquito control and bite prevention measures.

Epidemiological situation on West Nile Fever (WNF) in Europe in 2013 was characterized by a notable rise of morbidity rate primarily due to the outbreak of WNF in Serbia (302 cases registered). In the North America, in the United States and Canada, WNF manifestations in 2013 were characterized by the lower intensity compared to previous epidemic season. 192 cases were registered in 16 constituent entities of the Russian Federation in 2013. It was revealed, that genotype 2 West Nile Virus (WNV) circulated in the territory of the Volgograd and Saratov regions, the same as in Serbia, Greece and Italy, and genotype 1 WNV in the Astrakhan region. According to the data obtained from the Reference Center for monitoring over WNV pathogen, WNV markers were detected in the territory of 61 constituent entities of the Russian Federation throughout the period of observation in 1999-2013 which testified to the existence of potential risk of human exposure during epidemic season in most of the parts of country. According to Federal Service for Hydrometeorology and Environmental Monitoring forecast, climatic conditions in Russia for the next 5-10 years will stick to global warming trend which will contribute to further spread of WNV onto the northern areas.

White-tailed deer (WTD) are abundant mammals widely distributed across the United States. As a result, WTD are considered to be excellent sentinels for detecting arboviral activity in certain geographic areas. Evidence of West Nile virus (WNV) antibody in WTD has been reported previously in several states. However, WNV infection in WTD has not been reported from Texas, where the incidence of human West Nile (WN) cases is among the highest in the United States. Therefore, the aim of this study was to determine the prevalence of WNV antibody in WTD in central Texas. Sera samples (n = 644) were collected from deer during the fall and winter in western Travis County, Texas from 2014 to 2018 and tested for WNV immunoglobulin G (IgG) antibody by an indirect enzyme-linked immunosorbent assay (ELISA). ELISA antibody-positive samples were further tested for WNV and St. Louis encephalitis virus (SLEV) antibodies by an 80% plaque-reduction neutralization tests (PRNT80). Overall, 9% (n = 58) and 0.31% (n = 2) of the deer samples had serological evidence of WNV and SLEV infections, respectively. WNV seroprevalence differed significantly by age (p < 0.05), but there was no significant difference between sex. Interestingly, 3.1% (n = 20) of the samples were positive for Flavivirus IgG antibody by ELISA, but negative for SLEV and WNV antibodies, suggesting that other Flaviviruses may be circulating among WTD in Texas. Finally, these results supported WNV infection among WTD and highlight their potential role as sentinels for the detection of WNV in Texas and warrant further studies to determine the role WTD play in the maintenance and transmission of WNV.

Complement Protein C1q Reduces the Stoichiometric Threshold for Antibody-Mediated Neutralization of West Nile Virus

West Nile virus (WNV) is an arthropod‐borne virus transmitted mainly by mosquito bites. Wild avifauna constitutes its natural reservoir. Mammals are dead‐end hosts as they generally do not develop a viraemia high enough to trigger a new infection cycle. WNV belongs to theFlavivirusgenus and can be responsible for a disease known asWNfever. Humans and horses are the most sensitive hosts as they may develop severe neurological signs. WNV has a worldwide distribution and caused numerous outbreaks since the late 1990s, most notably in North America and Europe. Lineage 1 strains have caused the most severe outbreaks to date. However, the situation has recently evolved with the emergence in the late 2000s of pathogenic lineage 2 strains in South Africa, Russia and Eastern and Southern Europe. Many developments in the fields of WN diagnosis and vaccination have been described in the recent years and may help control WNV spread.Key ConceptsWest Nile virus (WNV) is a zoonotic arbovirus mainly transmitted by mosquitoes. It is an enveloped, positive‐stranded RNA virus belonging to the genusFlavivirusin the familyFlaviviridae.WNV has a wide geographical range that includes Europe, the Middle East, Western Asia, Africa, Australia (Kunjin virus) and North, Central and South America.Most WNV infections are asymptomatic, but can be responsible for a disease known as WN fever (10–20% of WNV infections) or severe neurological signs (1–10% of WNV infections) in humans and horses.Humans and horses are the most sensitive hosts.Since the late 1990s, pathogenic WNV strains have begun to emerge.Diagnosis can be difficult as flaviviruses are antigenically related.There are no effective drugs or treatments against WNV infections.Approved vaccines are available in equids, and human vaccines are under development.Control of WNV outbreaks largely depends on vector control measures and interventions.

The prevalence of West Nile (WN) virus infection in Karachi, Pakistan, was unknown until 1982. It had been noticed that there were more than a few patients with encephalitides in Karachi, and it was supposed that Japanese encephalitis (JE) cases would be found among them. Therefore, a seroepidemiological study was conducted to define the prevalence of WN virus infection and the possible occurrence of JE virus infection in the Karachi area. Prevalences of haemagglutination inhibition (HI) and neutralization (NT) antibodies against WN virus were studied among 81 serum samples (in July, 33 samples; in September, 48) during 1983, and among 156 paired serum samples that were collected twice, in July and October of 1985. Nearly the same antibody-positive rates were obtained in July of both years (1983: HI 55%; 1985: HI 53%; NT 50%); the rates increased slightly during September/October (1983: HI 65%; 1985: HI 59%, NT 54%). Among 156 paired samples in 1985, 20 (13%) and 12 (8%) showed positive- or negative-antibody conversion between July and October. Two serum samples from each of 156 residents obtained in July had a significantly higher NT antibody titre against JE virus than against WN virus (in case 1, JE 1:80, WN less than 1:10; in case 2, JE 1:40, WN less than 1:10). This is the first report to show the prevalence of WN virus infection in Karachi, Pakistan.

West Nile Virus (WNV) is an epizootic virus known to effectively kill Black-billed Magpies (Pica hudsonia). After WNV infection of humans appeared in the western United States, Black-billed Magpies birds per party-hours on Christmas Bird Counts (CBC) declined significantly. Trends for both CBC and Breeding Bird Surveys (BBS) shifted from positive before WNV infections of humans to negative during WNV infections, then rebounded to positive after WNV infection declined. Black-billed Magpies in Canada had no significant differences on CBC before or after WNV infections of humans. Canadian magpies had positive trends both before and after WNV infections on both CBC and BBS, but with negative trends during WNV infections. WNV invasion varied temporally across the continent, and Black-billed Magpies consistently showed significant and often dramatic declines soon after WNV invasion of a region. The southern Prairie region was severely hit, with Prairie states such as Kansas and Nebraska showing significant declines on CBC after WNV invasion, shifting from positive trends on CBC and BBS before invasion to negative trends during and after WNV invasion. WNV has potentially triggered or accelerated a retraction of Black-billed Magpie range in this region. The northern part of the Prairie region was less affected. Most southern and central Rocky Mountain, Intermountain, and Pacific region Black-billed Magpie populations showed significant negative effects from WNV infections. States in these regions with higher densities of Black-billed Magpies such as Colorado, Nevada, and Idaho showed significant dramatic declines during WNV invasion, but positive trends after WNV infections declined, a sign of recovering populations. California populations significantly declined with WNV invasion and have not recovered. Populations in northern and higher-elevation regions had little or no impact from WNV and populations were often stable or increasing.