Surveillance of West Nile virus infection in Kashgar Region, Xinjiang, China, 2013-2016.

West Nile virus (WNV) was first isolated in mainland China from mosquitoes in Jiashi County, Kashgar Region, Xinjiang in 2011, following local outbreaks of viral meningitis and encephalitis caused by WNV. To elaborate the epidemiological characteristics of the WNV, surveillance of WNV infection in Kashgar Region, Xinjiang from 2013 to 2016 were carried out. Blood and CSF samples from surveillance human cases, blood of domestic chicken, cattle, sheep and mosquitoes in Kashgar Region were collected and detected. There were human 65 WNV Immunoglobulin M (IgM) antibody positive cases by ELISA screening, 6 confirmed WNV cases by the plaque reduction neutralization test (PRNT) screening. These cases occurred mainly concentrated in August to September of each year, and most of them were males. WNV-neutralizing antibodies were detected in both chickens and sheep, and the positive rates of neutralizing antibodies were 15.5% and 1.78%, respectively. A total of 15,637 mosquitoes were collected in 2013-2016, with Culex pipiens as the dominant mosquito species. Four and 1 WNV-positive mosquito pools were detected by RT-qPCR in 2013 and 2016 respectively. From these data, we can confirm that Jiashi County may be a natural epidemic foci of WNV disease, the trend highlights the routine virology surveillance in WNV surveillance cases, mosquitoes and avian should be maintained and enhanced to provide to prediction and early warning of outbreak an epidemic of WNV in China.

Acute and Delayed Deaths after West Nile Virus Infection, Texas, USA, 2002-2012.

Infection with West Nile virus (WNV) has a well-characterized acute disease process. However, long-term consequences are less understood. We searched death records for 4,142 residents of Texas, USA, infected with WNV during 2002-2012 and identified 557 (13%) deaths. We analyzed all-cause and cause-specific deaths after WNV infection by calculating standardized mortality ratios and using statewide mortality data. Acute-phase deaths (<90 days after symptom onset) occurred in 289 (7%) of case-patients; of those deaths, 289 (92%) were cases of West Nile neuroinvasive disease (WNND). Convalescent-phase deaths (>90 days after symptom onset) occurred in 268 (7%) of the remaining 3,853 case-patients; 210 (78%) of these deaths occurred in patients with WNND. Convalescent-phase WNND case-patients showed excess deaths from infectious and renal causes; case-patients <60 years of age had increased risk for all-cause death, specifically from renal, infectious, digestive, and circulatory causes. We provide population-level evidence of increased risk for death after WNV infection resulting in WNND.

Cumulative Incidence of West Nile Virus Infection, Continental United States, 1999-2016.

Using reported case data from ArboNET and previous seroprevalence data stratified by age and sex, we conservatively estimate that ≈7 million persons in the United States have been infected with West Nile virus since its introduction in 1999. Our data support the need for public health interventions and improved surveillance.

Co-circulation dynamics and persistence of newly introduced clades of 2012 outbreak associated West Nile Virus in Texas, 2012-2015.

The second largest outbreak of West Nile encephalitis and West Nile fever ever recorded occurred in the United States (U.S) in the summer of 2012. The outbreak was related to the widespread circulation of closely related clades, or groups, of West Nile virus (WNV) into multiple states where they were not previously found. Whether the invading 2012 strains were able to circulate and overwinter in states with their own endemic population of WNV is unknown and the effect of viral genetics on adaptation and persistence in a new ecological niche is unclear. In this study, we sequenced 70 mosquito isolates from multiple counties throughout Texas in 2012-2015. We identified isolates representative of previously described 2012 WNV groups (Groups 8-10) and discovered a novel group which we called Group 11. Although we identified isolates representative of WNV endemic (2/70) to Texas, most isolates (68/70) were related to the invading 2012 strains, and of these Group 10 (45/68) was predominant. We also observed differences among the 2012 WNV groups correlating to their genotype. Group 10 WNV in Texas, which carry two putative positively selected variants, had limited introductions into Texas, wide circulation, and strong evidence of continued persistence perhaps indicative of overwintering. In contrast, Groups 8 and 11, without positively selected variants, had multiple introductions into Texas, limited circulation, and limited persistence. Lastly, we identified a potential transmission source in New York for incoming Group 8 WNV into Texas. Altogether our study suggests that mutations in the WNV genome may influence the range and dynamics of WNV circulation, and the ability of different strains to persist in new ecological niches.

West Nile Virus Outbreak in Houston and Harris County, Texas, USA, 2014.

Since 2002, West Nile virus (WNV) has been detected every year in Houston and the surrounding Harris County, Texas. In 2014, the largest WNV outbreak to date occurred, comprising 139 cases and causing 2 deaths. Additionally, 1,286 WNV-positive mosquito pools were confirmed, the most reported in a single mosquito season.

Historical Perspectives on Flavivirus Research.

The flaviviruses are small single-stranded RNA viruses that are typically transmitted by mosquito or tick vectors. These "arboviruses" are found around the world and account for a significant number of cases of human disease. The flaviviruses cause diseases ranging from mild or sub-clinical infections to lethal hemorrhagic fever or encephalitis. In many cases, survivors of neurologic flavivirus infections suffer long-term debilitating sequelae. Much like the emergence of West Nile virus in the United States in 1999, the recent emergence of Zika virus in the Americas has significantly increased the awareness of mosquito-borne viruses. The diseases caused by several flaviviruses have been recognized for decades, if not centuries. However, there is still a lot that is unknown about the flaviviruses as the recent experience with Zika virus has taught us. The objective of this review is to provide a general overview and some historical perspective on several flaviviruses that cause significant human disease. In addition, available medical countermeasures and significant gaps in our understanding of flavivirus biology are also discussed.

Correlation of West Nile Virus Incidence in Donated Blood with West Nile Neuroinvasive Disease Rates, United States, 2010-2012.

Over the past decade, West Nile virus (WNV) has spread across the United States. We aggregated blood donor data from 2010-2012 and then calculated the incidence of WNV RNA-positive donations and compared the incidence with neuroinvasive disease (NID) case data from the ArboNET surveillance system. Of 10,107,853 donations, 640 were confirmed positive. The seasonal WNV incidence rate per 100,000 persons was 33.4 (95% CI 22-45) in 2010, 25.7 (95% CI 15-34) in 2011, and 119.9 (95% CI 98-141) in 2012. NID to blood donor ratios were 1 in 164 (95% CI 152-178) in 2010, 1 in 158 (95% CI 145-174) in 2011, and 1 in 131 (95% CI 127-136) in 2012. We updated estimates of the ratio of NID to WNV infection rates, demonstrating stable disease penetrance over the study period. Blood donor WNV RNA screening is a valuable public health tool for WNV surveillance.

West nile virus in the United States - a historical perspective.

Prior to 1999, West Nile virus (WNV) was a bit player in the screenplay of global vector-borne viral diseases. First discovered in the West Nile District of Uganda in 1937, this Culex sp.-transmitted virus was known for causing small human febrile outbreaks in Africa and the Middle East. Prior to 1995, the last major human WNV outbreak was in the 1950s in Israel. The epidemiology and ecology of WNV began to change in the mid-1990s when an epidemic of human encephalitis occurred in Romania. The introduction of WNV into Eastern Europe was readily explained by bird migration between Africa and Europe. The movement of WNV from Africa to Europe could not, however, predict its surprising jump across the Atlantic Ocean to New York City and the surrounding areas of the United States (U.S.). This movement of WNV from the Eastern to Western Hemisphere in 1999, and its subsequent dissemination throughout two continents in less than ten years is widely recognized as one of the most significant events in arbovirology during the last two centuries. This paper documents the early events of the introduction into and the spread of WNV in the Western Hemisphere.

Epidemiological history and phylogeography of West Nile virus lineage 2.

West Nile virus (WNV) was first isolated in Uganda. In Europe WNV was sporadically detected until 1996, since then the virus has been regularly isolated from birds and mosquitoes and caused several outbreaks in horses and humans. Phylogenetic analysis showed two main different WNV lineages. The lineage 1 is widespread and segregates into different subclades (1a-c). WNV-1a includes numerous strains from Africa, America, and Eurasia. The spatio-temporal history of WNV-1a in Europe was recently described, identifying two main routes of dispersion, one in Eastern and the second in Western Europe. The West Nile lineage 2 (WNV-2) is mainly present in sub-Saharan Africa but has been recently emerged in Eastern and Western European countries. In this study we reconstruct the phylogeny of WNV-2 on a spatio-temporal scale in order to estimate the time of origin and patterns of geographical dispersal of the different isolates, particularly in Europe. Phylogeography findings obtained from E and NS5 gene analyses suggest that there were at least two separate introductions of WNV-2 from the African continent dated back approximately to the year 1999 (Central Europe) and 2000 (Russia), respectively. The epidemiological implications and clinical consequences of lineage 1 and 2 cocirculation deserve further investigations.

Enfermedad del Nilo Occidental, evolución histórica y control de foco en Cuba / Western Nile Disease, historical evolution and focus control in Cuba

Se realizó una revisión bibliográfica sobre la enfermedad del Nilo Occidental y su evolución histórica desde el descubrimiento en 1937 en Egipto, hasta la detección en el continente americano en los Estados Unidos en 1999 y su posterior diseminación a otros países cercanos, incluyendo a Cuba en el año 2005. Se realizó la caracterización clínico epidemiológica de la enfermedad, se establecieron los criterios para la definición de casos y todas las actividades a desarrollar en Cuba como el diagnóstico, atención médica, tratamiento y control de foco, no solo por el Ministerio de Salud Pública sino por todos los ministerios vinculados al sistema de protección y vigilancia en humanos, aves y equinos.

A bibliographical revision was carried out on Western Nile disease and its historical evolution from discovery in 1937 in Egypt, to detection in the American continent in the United States, 1999 and their later dissemination to other near countries including Cuba in 2005. A clinical and epidemiological characterization of the disease was carried out, the criteria were established for defining cases and all the activities to develop in Cuba (diagnosis, medical attention, treatment, focus control), not only by the Ministry of Public Health but by the entire linked ministry to the protection and monitoring system human, birds and equine.

Enfermedad del Nilo Occidental, evolución histórica y control de foco en Cuba / Western Nile Disease, historical evolution and focus control in Cuba

Se realizó una revisión bibliográfica sobre la enfermedad del Nilo Occidental y su evolución histórica desde el descubrimiento en 1937 en Egipto, hasta la detección en el continente americano en los Estados Unidos en 1999 y su posterior diseminación a otros países cercanos, incluyendo a Cuba en el año 2005. Se realizó la caracterización clínico epidemiológica de la enfermedad, se establecieron los criterios para la definición de casos y todas las actividades a desarrollar en Cuba como el diagnóstico, atención médica, tratamiento y control de foco, no solo por el Ministerio de Salud Pública sino por todos los ministerios vinculados al sistema de protección y vigilancia en humanos, aves y equinos(AU)

A bibliographical revision was carried out on Western Nile disease and its historical evolution from discovery in 1937 in Egypt, to detection in the American continent in the United States, 1999 and their later dissemination to other near countries including Cuba in 2005. A clinical and epidemiological characterization of the disease was carried out, the criteria were established for defining cases and all the activities to develop in Cuba (diagnosis, medical attention, treatment, focus control), not only by the Ministry of Public Health but by the entire linked ministry to the protection and monitoring system human, birds and equine(AU)

Phylogeography and epidemiological history of West Nile virus genotype 1a in Europe and the Mediterranean basin.

Aim of this study was to reconstruct the temporal and spatial phylodynamics of WNV-1a, the genotype to which the majority of European/Mediterranean viral strains belongs, by using sequences retrieved from public databases. WNV-1a isolates segregated into two major clades: the recent West Mediterranean sequences formed a single monophyletic group within clade A. Clade B included sequences from East Mediterranean and America. Phylogeographic analysis suggested that WNV-1a probably originated in sub-Saharan Africa in the early XXth century, and then spread northwards since the late 1970s, via two routes: one crossing Eastern Mediterranean and the other the Western Mediterranean countries. Our data suggest that the circulation of the virus in a given geographical area usually precedes the onset of the outbreak by one year or more, and underline the importance of the spatial-temporal phylodynamics reconstruction in clarifying the recent epidemiology and in setting up an efficient surveillance system for emerging/reemerging zoonosis.

Alexander's (356-323 BC) expeditionary Medical Corps 334-323 BC.

Alexander had a profound interest in medicine and healing. Original Greek texts survive mainly from the works of Plutarch and Arrian. This paper examines original sources naming the physicians who participated in Alexander's expedition in Asia, the battle injuries he sustained and his final illness in Babylon.

Emerging infectious diseases at the beginning of the 21st century.

The emergence and re-emergence of infectious diseases involves many interrelated factors. Global interconnectedness continues to increase with international travel and trade; economic, political, and cultural interactions; and human-to-human and animal-to-human interactions. These interactions include the accidental and deliberate sharing of microbial agents and antimicrobial resistance and allow the emergence of new and unrecognized microbial disease agents. As the 21st century begins, already new agents have been identified, and new outbreaks have occurred. Solutions to limiting the spread of emerging infectious diseases will require cooperative efforts among many disciplines and entities worldwide. This article defines emerging infectious diseases, summarizes historical background, and discusses factors that contribute to emergence. Seven agents that have made a significant appearance, particularly in the 21st century, are reviewed, including: Ebola and Marburg hemorrhagic fevers, human monkeypox, bovine spongiform encephalopathy, severe acute respiratory syndrome (SARS), West Nile virus, and avian influenza. The article provides for each agent a brief historical background, case descriptions, and health care implications.