Cases Of West Nile Neuroinvasive Disease Research Articles

West Nile virus transmission with human cases in Italy, August - September 2009

In 2009, to date 16 human cases of West Nile neuroinvasive disease (WNND) have been reported in Italy, in three regions: Veneto, Emilia-Romagna and Lombardia. The number of cases is higher compared with last year when nine cases were identified (eight cases of WNND and one case of West Nile fever) and the geographical distribution indicates spread from east to west.

Declining Mortality in American Crow (Corvus brachyrhynchos) Following Natural West Nile Virus Infection

The American crow (Corvus brachyrhynchos) is known to suffer 100% mortality from infection with the New York 1999 strain of West Nile virus (WNV). Following the initial detection of WNV in North America in 1999, we measured prevalence of WNV-reactive antibodies ("seroprevalence") in free-ranging American and fish crows (Corvus ossifragus) of central New Jersey after each transmission season through 2005. In 2002, seroprevalence in American crow juveniles increased to 14% from the 5% of the previous year, potentially indicating increased survival in this species. Using the annual seroprevalence measurements and the number of human West Nile neuroinvasive disease cases as a surrogate for WNV transmission intensity, we developed a model to estimate the annual WNV-associated mortality rates among both of these crow species. Our model supports the hypothesis that mortality is changing over time; the WNV-associated mortality rate declined over time by 1.5% for American crow and by 1.1% for fish crow. The probability that the trend in mortality was negative was 90% for the American crow and 60% for the fish crow.

West Nile Virus Disease in Children, United States, 1999–2007

Although West Nile virus (WNV) disease has occurred predominantly among adults in the United States, children are also susceptible. Epidemiological data describing WNV disease in children are limited. We described the epidemiological features of WNV disease among children (<18 years of age) reported to the Centers for Disease Control and Prevention from 1999 through 2007 and compared features of pediatric and adult West Nile neuroinvasive disease (WNND). Of 1478 pediatric WNV cases reported from 1999 through 2007, 443 (30%) were classified as WNND, 1009 (68%) were classified as West Nile fever, and 26 (2%) were of unknown clinical presentation. Three WNND cases were fatal. The vast majority of reported case subjects (92%) had onset of illness between July and September. Children accounted for only 4% of all of the WNND case subjects reported from 1999 to 2007, with a median annual incidence of 0.07 case subjects per 100 000 children (range: 0.00-0.19 case subjects). In children and younger adults WNND most often manifested as meningitis, in contrast to the predominance of encephalitis among older adults with WNND. The geographic distribution and temporal trends were of pediatric and adult WNND. The epidemiological characteristics of WNV disease in children are similar to adult case subjects; however, WNND is more likely to manifest as meningitis in children than in older adults. WNV should be considered in the differential diagnosis for pediatric patients presenting with febrile illness, meningitis, encephalitis, or acute flaccid paralysis, particularly during seasonal outbreaks in endemic areas.

Effect of Hurricane Katrina on Arboviral Disease Transmission

Effect of Hurricane Katrina on Arboviral Disease Transmission