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This article presents information from studies conducted by the U.S. Centers for Disease Control and Prevention (CDC). This study examines West Nile Virus (WNV) Activity in the U.S. during 2006. During 2006, WNV transmission to humans or animals expanded into 52 counties that had not previously reported cases and recurred in 1,350 counties where it had been reported before. Nearly 1,500 cases of WNV neuroinvasive disease (WNND) were reported for a 14 percent increase over 2005. In humans, a total of 4,261 cases were reported and the number is almost the same in birds. Horses and squirrels also showed significant infection. Community level mosquito control is the most effective way of reducing the disease.

The article discusses West Nile Virus (WNV), which is a cause of arboviral encephalitis in the United States. WNV activity during January 1-December 1, 2005 included WNV neuroinvasive disease (WNND). Demographic data indicates there were outbreaks of WWND and WNV disease in California, Illinois, Texas, Louisiana, South Dakota, Nebraska, North Dakota, and the New York City metropolitan area. The CDC editorial note focuses on the endemic transmission of WNV in people and animals, as well as the effectiveness of the ArboNET surveillance system in detecting increased transmission of the virus.

Objective: To estimate the number of persons infected with the human immunodeficiency virus (HIV) living in the United States and the change in HIV infection prevalence since 1984., Design: We estimated HIV prevalence from 3 data sources. We estimated past HIV infection rates from a statistical procedure based on national acquired immunodeficiency syndrome (AIDS) case surveillance data and estimates of the time from HIV infection to AIDS diagnosis. We also analyzed HIV prevalence data from 2 national surveys, a survey of childbearing woman and a household survey of current health status. We used other data sources to adjust these survey estimates to include groups not covered in the surveys., Results: Approximately 0.3% of US residents (650,000-900,000 persons) were infected with HIV in 1992. Approximately 0.6% of men (including adolescent boys > or = 13 years of age) were infected, including approximately 2% of non-Hispanic black men and 1% of Hispanic men. Approximately 0.1% of women (including adolescent girls > or = 13 years of age) were infected, including approximately 0.6% of non-Hispanic black women. Approximately half of all infected persons were men who had sex with men, and one fourth were injecting drug users. The prevalence of HIV infection increased from 1984 to 1992, with a greater relative increase among women than men., Conclusions: The 3 different data sources and methods are consistent in estimating that 650,000 to 900,000 persons were infected with HIV in the United States in 1992. Among adolescents and adults of both sexes, the proportion infected was substantially higher among non-Hispanic blacks and Hispanics than among non-Hispanic whites. HIV-related illness will be a major clinical and public health problem in the United States for years to come.

Objective: To describe trends in the prevalence of human immunodeficiency virus (HIV) among socially and educationally disadvantaged US youth., Design: Analysis of demographic and geographic trends of HIV infection among Job Corps students from January 1988 through December 1992., Setting: The Job Corps is a national training program for disadvantaged and out-of-school youth. POPULATION SCREENED: Youths aged 16 to 21 years who entered the Job Corps residential training centers during the survey period., Main Outcome Measure: Trends in prevalence of HIV infection among Job Corps students stratified by sex, age, race, and region of the country., Results: Of the 269,956 Job Corps students screened, 812 (0.3%) tested positive for the antibody to HIV type 1. Seroprevalence of HIV for young men decreased from 3.6 per 1000 in 1988 to 2.2 per 1000 in 1992 (chi 2 test for trend, P < .001). Seroprevalence for young women increased from 2.1 per 1000 in 1988 to 4.2 per 1000 in 1990 (P = .001), with seroprevalence remaining stable from 1990 through 1992. The decreasing trends in HIV prevalence among men and increasing trends among women were primarily due to changes in seroprevalence in African-American students., Conclusions: The overall prevalence of HIV infection of three per 1000 is high, given the youth of Job Corps students. The significant rise in HIV rates among female Job Corps students provides evidence of the increasing risk of infection for socioeconomically disadvantaged young women. Reasons for the declining trend in HIV prevalence among male Job Corps students are not clear. Efforts to prevent the spread of HIV infection among adolescents must focus on the group that is hardest to reach--out-of-school and impoverished youth.

Objective: To assess the extent of the human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) epidemic in the District of Columbia and demonstrate an approach to monitoring HIV infection and projecting AIDS incidence at a community level., Design: Backcalculation methods to reconstruct HIV incidence from AIDS incidence in subgroups. Results were compared with directly measured HIV seroprevalence in selected sentinel populations: childbearing women, civilian applicants for military service, and hospital patients admitted for conditions unrelated to HIV infection., Results: Between the start of the epidemic in 1980 and January 1, 1991, one in 57 District of Columbia men aged 20 to 64 years was diagnosed with AIDS. Unlike the plateau projected for the nation, AIDS incidence for the District of Columbia was projected to increase by 34% between 1990 and 1994. Models of HIV infection incidence suggested two broad epidemic waves of approximately equal size. The first occurred in men who have sex with men and peaked during the period from 1982 through 1983. The second began in the mid-1980s in injecting drug users and heterosexuals. We estimated that among District of Columbia residents aged 20 to 64 years, 0.3% of white women, 2.9% of white men, 1.6% of black women, and 4.9% of black men were living with HIV infection as of January 1, 1991. These estimates are broadly consistent with survey data: among black childbearing women in their 20s, HIV prevalence doubled to 2% between the fall of 1989 and the spring of 1991; from military applicant data, we estimated that over 5% of black men born from 1951 through 1967 were HIV-positive; in the sentinel hospital, HIV prevalence rates among male patients aged 25 to 34 years were 11.3% in white men and 16.9% in black men., Conclusion: Backcalculation and surveys yielded quantitatively consistent estimates of HIV prevalence. Many injecting drug users and heterosexuals in the District of Columbia were infected after January 1, 1986. Similar monitoring of the epidemic in other localities is needed to focus efforts to reduce the incidence of HIV transmission.

Unlabelled: OBJECTIVE--To describe the human immunodeficiency virus (HIV) epidemic among socially and educationally disadvantaged young persons in the United States., Design: -We analyzed demographic and geographic findings from the screening of Job Corps students for antibody to HIV. SETTING--The Job Corps is a federal training program for disadvantaged, out-of-school youth. POPULATION SCREENED--Residential students aged 16 to 21 years who entered the Job Corps from October 1987 through February 1990. MAIN OUTCOME MEASURE--Rates of observed HIV infection in entering students, stratified by demographic and geographic features. RESULTS--Of 137,209 Job Corps students screened, 488 were HIV seropositive (3.6 per 1000), a seroprevalence rate higher than that among military applicants of the same age. Overall seroprevalence was slightly higher in male (3.7 per 1000) than in female (3.2 per 1000) Job Corps students, but among those students aged 16 and 17 years, seroprevalence was higher among females (2.3 per 1000) than among males (1.5 per 1000) (P less than .05). For students aged 16 to 21 years, seroprevalence increased with year of age: 1.8 per 1000 per year for males and 0.7 per 1000 per year for females. Among those aged 21 years, HIV prevalence was 8.9 per 1000. For black and Hispanic students from large Northeastern cities, seroprevalence increased by 4.3 per 1000 per year of age and reached 24.8 per 1000 (one of 40) in students aged 21 years. However, among students from rural areas and small towns, HIV seroprevalence was disproportionately high in the Southeast. Compared with recently described US patients with the acquired immunodeficiency syndrome, HIV-infected students who entered the Job Corps were much more likely to be female. CONCLUSIONS--These findings show that disadvantaged, out-of-school adolescents are at high risk for HIV infection. The screening results identified surprisingly high seroprevalence in the southeastern United States and demonstrated a marked shift in the HIV epidemic to young women. Controlling the HIV epidemic among teenagers must include interventions that will reach adolescents early and outside of the formal educational system.