Cases Of West Nile Disease Research Articles

A parsimonious Bayesian predictive model for forecasting new reported cases of West Nile disease

Upon researching predictive models related to West Nile virus disease, it is discovered that there are numerous parameters and extensive information in most models, thus contributing to unnecessary complexity. Another challenge frequently encountered is the lead time, which refers to the period for which predictions are made and often is too short. This paper addresses these issues by introducing a parsimonious method based on ICC curves, offering a logistic distribution model derived from the vector-borne SEIR model. Unlike existing models relying on diverse environmental data, our approach exclusively utilizes historical and present infected human cases (number of new cases). With a year-long lead time, the predictions extend throughout the 12 months, gaining precision as new data emerge. Theoretical conditions are derived to minimize Bayesian loss, enhancing predictive precision. We construct a Bayesian forecasting probability density function using carefully selected prior distributions. Applying these functions, we predict month-specific infections nationwide, rigorously evaluating accuracy with probabilistic metrics. Additionally, HPD credible intervals at 90%, 95%, and 99% levels is performed. Precision assessment is conducted for HPD intervals, measuring the proportion of intervals that does not include actual reported cases for 2020–2022.

Epidemiological and Evolutionary Analysis of West Nile Virus Lineage 2 in Italy.

West Nile virus (WNV) is a mosquito-borne virus potentially causing serious illness in humans and other animals. Since 2004, several studies have highlighted the progressive spread of WNV Lineage 2 (L2) in Europe, with Italy being one of the countries with the highest number of cases of West Nile disease reported. In this paper, we give an overview of the epidemiological and genetic features characterising the spread and evolution of WNV L2 in Italy, leveraging data obtained from national surveillance activities between 2011 and 2021, including 46 newly assembled genomes that were analysed under both phylogeographic and phylodynamic frameworks. In addition, to better understand the seasonal patterns of the virus, we used a machine learning model predicting areas at high-risk of WNV spread. Our results show a progressive increase in WNV L2 in Italy, clarifying the dynamics of interregional circulation, with no significant introductions from other countries in recent years. Moreover, the predicting model identified the presence of suitable conditions for the 2022 earlier and wider spread of WNV in Italy, underlining the importance of using quantitative models for early warning detection of WNV outbreaks. Taken together, these findings can be used as a reference to develop new strategies to mitigate the impact of the pathogen on human and other animal health in endemic areas and new regions.

First neuroinvasive human case of West Nile Disease in Southern Italy: Results of the ‘One Health’ approach

BackgroundWest Nile Disease (WND) is a zoonotic mosquito‐borne infection involving viral pathogens, human and animal hosts, vectors and environment. Cooperation among medical, veterinary and entomological fields has been promoted by the Italian Public Health Authorities, and an integrated West Nile Virus (WNV) Surveillance Plan has been in force in Italy since 2016 to prevent the transmission risk of WND to humans through an early detection of viral circulation by animal and entomological surveillance. This managing model is unique in Europe.ObjectivesThis survey aimed at presenting the ‘One Health’ approach applied in 2016 to the first autochthonous human case of West Nile Neuroinvasive Disease (WNND) in Sicily (Southern Italy).MethodsSerological (anti‐WNV IgM and IgG ELISA, anti‐WNV neutralizing antibodies) and molecular tests were conducted on blood, liquor and urine of a 38‐year‐old man with encephalitis and meningitis. Overall, 2704 adult culicides from 160 mosquito catches were morphologically identified. Female mosquitoes were analysed in pools for WNV RNA detection. Serological (anti‐WNV IgM and IgG ELISA) and molecular analyses for WNV were carried out in 11 horses, 271 chickens and two dogs sampled in farms around the man's residence.Results and conclusionsWNND was confirmed by serological analysis on patient's liquor and serum. Collected mosquito species included Culex pipiens (93.56%, CI95% 92.64%–94.49%), Aedes albopictus (5.25%, CI95% 4.41%–6.09%), Culex hortensis (0.59%, CI95% 0.30%–0.88%), Culiseta longiareolata (0.55%, CI95% 0.27%–0.83%) and Anopheles maculipennis s.l. (0.04%, CI95% –0.04% to 0.11%). Mosquito pools were negative for WNV RNA. Two dogs (100%) and two horses (18.18%, CI95% –4.61 to 40.97%) resulted positive for anti‐WNV specific antibodies.The ‘One Health’ approach allowed to report the first human neuroinvasive WND in Sicily and to confirm the local circulation of WNV in animals of the same area where the clinical case occurred, defining the autochthonous origin of the infection.

Early detection of West Nile Virus mosquitoes and cases in Frisco and Dallas in 2019 using DNA &RNA testing and Climatic prediction with Math lab followed by Descriptive statistical analysis using R-programming

West Nile Virus is a mosquito borne disease that is initially caused in continental US that leads to neurological disease and death. There exists no vaccine or particular antiviral treatment for WNV.The mosquitoes become infected when they bite the infected birds. WNV is confined to the family Flaviviridae containing single stranded positive RNA with 11kb length. The purpose of this paper is to study WNV human cases and WNV positive mosquito traps in Frisco 75035 from Sep-Oct 2019. Also, the paper aims in explaining the current CDC data on WNV cases in detail using descriptive computer statistical analysis method. The data describes the current 2019 WNV neuro cases, WNV non-neuro cases, Death and presumptive viremic blood donors. According to (DSHS, 2019), there is no WNV cases reported yet in Frisco 2019 and one positive WNV case in Dallas county. According to CDC (2019), out of total 777, 98 were presumptive viremic blood donors, 504 was neuro-invasive cases, 273 were non-neuro-invasive cases, and 39 death was reported. Arizona and Colorado have the highest number of WNV Neuro invasive and Non-neuro-invasive cases of 132 and 60. This summary statistics reveals Neuro invasive cases have higher mean of 11.45 to non-neuro-invasive with 6.205. On the T-test it reveals at 95 % confidence level (P=0.007681) a significant difference in total cases versus the presumptive blood donors. It also represents more positive relationship on the scatter plots. According to Texas Department of state Health and Human Services (2019), reported human cases of reportable West Nile Disease of 19; out of which West Nile encephalitis is 15 and West Nile fever is 4. This shows that in Texas there is a drastic reduction of West Nile disease cases reported in 2019 related to good surveillance plans. This review summarizes descriptive statistical analysis of 2019 WNV cases which has shown a new increase in Presumptive viremic blood donors which is the hall mark of this review. Finally, the paper has completed a climatic niche prediction model using Math lab computer software for the future prediction of WNV positive mosquitoes using climatic conditions like high temperature, low temperature, humidity, rainfall, and precipitation.

Genetic Variability of West Nile Virus in U.S. Blood Donors from the 2012 Epidemic Season.

West Nile virus (WNV) is an arbovirus maintained in nature in a bird-mosquito enzootic cycle which can also infect other vertebrates including humans. WNV is now endemic in the United States (U.S.), causing yearly outbreaks that have resulted in an estimated total of 4–5 million human infections. Over 41,700 cases of West Nile disease, including 18,810 neuroinvasive cases and 1,765 deaths, were reported to the CDC between 1999 and 2014. In 2012, the second largest West Nile outbreak in the U.S. was reported, which caused 5,674 cases and 286 deaths. WNV continues to evolve, and three major WNV lineage I genotypes (NY99, WN02, and SW/WN03) have been described in the U.S. since introduction of the virus in 1999. We report here the WNV sequences obtained from 19 human samples acquired during the 2012 U.S. outbreak and our examination of the evolutionary dynamics in WNV isolates sequenced from 1999–2012. Maximum-likelihood and Bayesian methods were used to perform the phylogenetic analyses. Selection pressure analyses were performed with the HyPhy package using the Datamonkey web-server. Using different codon-based and branch-site selection models, we detected a number of codons subjected to positive pressure in WNV genes. Thirteen of the 19 completely sequenced isolates from 10 U.S. states were genetically similar, sharing up to 55 nucleotide mutations and 4 amino acid substitutions when compared with the prototype isolate WN-NY99. Overall, these analyses showed that following a brief contraction in 2008–2009, WNV genetic divergence in the U.S. continued to increase in 2012, and that closely related variants were found across a broad geographic range of the U.S., coincident with the second-largest WNV outbreak in U.S. history.

Analysis of climatic and environmental variables associated with the occurrence of West Nile virus in Morocco

West Nile disease (WND) is one of the most widespread mosquito-borne infectious diseases in the World. In Morocco the first WND cases were reported in equines in 1996. After an apparent epidemiological silence, WND re-occurred in 2003 and in 2010, when the disease was reported in equines living in the central and north-western part of the country. Eco-climatic variables are known to influence the mosquito presence and abundance and, therefore, the probability of occurrence of mosquito-borne infections. The remote sensed values of Land Surface Temperature (LST), Normalised Difference Vegetation Index (NDVI) and rainfall registered from 2001 to 2010 were evaluated for a possible association with the occurrence of WND cases in 2003 and in 2010. In the zones where WND cases occurred, NDVI values recorded in 2003 and 2010, from June to November, were significantly higher than those registered during the same months in the rest of the decade. Rainfall data showed higher peaks in 2003 and 2010, when the number of days with extreme rainfall was significantly higher during 1–2 months before the occurrence of WND cases. Temperature does not seem to play an important role in Moroccan epidemiological conditions.

Importance of dogs as sentinels of West Nile Virus activity in urban and suburban areas

Background: West Nile Virus (WNV) is a virus included in the Japanese encephalitis sero-complex within the genus Flavivirus. In August 2010, cases of West Nile disease were reported for the first time in Sicily. Neurological symptomswere observed in native horses resident in the rural areas around the province of Trapani, in the western part of the island. During the epidemic, important critical questions onwhen the viruswas introduced in the area and aboutwhether the virus had circulated/was circulating in theurban area, emerged and needed to be answered. A retrospective study using dog serum samples was designed to answer these questions. Methods: Between January 2009 and September 2010, 182 sera were collected by public and private vets and examined for the presence of WNV neutralising antibodies by using neutralisation assays. All samples belonged to urban dogs hosted in animal shelters or staying in vet surgeon located in towns of the western area of Sicily. Results: Out of the 182 samples tested, 11 (6.0%) had WNV neutralising antibodies with titres ranging from 1:10 to 1:80. A prevalence of 2.7% (n=74) was found in dogs sampled in 2009 whereas a prevalence of 8.3% (n=108) in the animals sampled in 2010. The highest prevalence (12.9%) was found in samples collected in the moth of September 2010 (n=31). WNV neutralizing titers were also found in a dog sampled in May 2009. There was a complete correspondence between areas with positive dogs and areas where the WND horse cases occurred. Conclusion: WNV infected dogs have been frequently detected in serological surveys. Even though not playing a major role in the epidemiology of WNV, dogs have been shown to be incidentally involved in the maintenance of the virus. This WNV retrospective study on dog sera was extremely useful to prove that WNV was in Sicily far before the first reported clinical case and that the virus had circulated/was circulating in the urban areas. It confirms the importance of these domestic animals as sentinels for either early detection or monitoring the virus activity in urban and sub-urban areas with possible threat to human health.

Yard Flooding by Irrigation Canals Increased the Risk of West Nile Disease in El Paso, Texas

To investigate the effects of use of water from irrigation canals to flood residential yards on the risk of West Nile disease in El Paso, Texas. West Nile disease confirmed cases in 2009 through 2010 were compared with a random sample of 50 residents of the county according to access to and use of water from irrigation canals by subjects or their neighbors, as well as geo-referenced closest distance between their home address and the nearest irrigation canal. A windshield survey of 600 m around the study subjects' home address recorded the presence of irrigation canals. The distance from the residence of 182 confirmed cases of West Nile disease reported in 2003 through 2010 to canals was compared with that of the centroids of 182 blocks selected at random. Cases were more likely than controls to report their neighbors flooded their yards with water from canals. Irrigation canals were more often observed in neighborhoods of cases than of controls. Using the set of addresses of 182 confirmed cases and 182 hypothetical controls the authors found a significant, inverse relation with risk of West Nile disease. Flooding of yards with water from canals increased the risk of West Nile disease.

Detection and molecular analysis of West Nile virus infections in birds of prey in the eastern part of Austria in 2008 and 2009

The emergence of West Nile virus (WNV) was expected in Austria since the initial discovery of the infection in neighbouring Hungary in 2003/2004. In 2008 six cases of West Nile disease were diagnosed at the Institute for Veterinary Disease Control Mödling, Austrian Agency for Health and Food Safety (AGES), involving five goshawks (Accipiter gentilis) and one gyrfalcon (Falco rusticolus), which were found dead in the eastern Austrian federal states of Lower Austria, Vienna and Styria, respectively. Pathomorphological and immunohistochemical findings suggested a WNV infection. Virus was isolated in embryonated specific pathogen free chicken eggs and propagated in mouse neuroblastoma cells (NA), in which a cytopathic effect occurred. The virus was identified and characterised by electron microscopic examination and molecular detection using RT-PCR, sequencing, and phylogenetic analysis. The Austrian WNV sequences exhibited nucleotide identities of 99.9% to the lineage 2 WNV sequences described in Hungary since 2004. In addition, 71 sera of 14 different bird species were screened for the presence of WNV antibodies using a commercial ELISA: 43.7% of the tested samples showed antibody titers. Selected positive sera were also subjected to WNV neutralisation tests, in which the ELISA results were verified in 66%. The results of this study confirm unambiguously the presence of a lineage 2 WNV infection in birds of prey in the eastern part of Austria.

Fatal Human Case of West Nile Disease, Mexico, 2009

Fatal Human Case of West Nile Disease, Mexico, 2009

Incidence and effects of West Nile virus infection in vaccinated and unvaccinated horses in California

A prospective cohort study was used to estimate the incidence of West Nile virus (WNV) infection in a group of unvaccinated horses (n = 37) in California and compare the effects of natural WNV infection in these unvaccinated horses to a group of co-mingled vaccinated horses (n = 155). Horses initially were vaccinated with either inactivated whole virus (n = 87) or canarypox recombinant (n = 68) WNV vaccines during 2003 or 2004, prior to emergence of WNV in the region. Unvaccinated horses were serologically tested for antibodies to WNV by microsphere immunoassay incorporating recombinant WNV E protein (rE MIA) in December 2003, December 2004, and every two months thereafter until November 2005. Clinical neurologic disease attributable to WNV infection (West Nile disease (WND)) developed in 2 (5.4%) of 37 unvaccinated horses and in 0 of 155 vaccinated horses. One affected horse died. Twenty one (67.7%) of 31 unvaccinated horses that were seronegative to WNV in December, 2004 seroconverted to WNV before the end of the study in November, 2005. Findings from the study indicate that currently-available commercial vaccines are effective in preventing WND and their use is financially justified because clinical disease only occurred in unvaccinated horses and the mean cost of each clinical case of WND was approximately 45 times the cost of a 2-dose WNV vaccination program.