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An inexpensive enzyme-linked immunosorbent assay method for human immunodeficiency virus type 1 quantitation, ultrasensitive p24 antigen assay (Up24), was compared with RNA viral load assay (VL). Up24 had 100% sensitivity of detection at a viral load of >/=30,000, with sensitivity of 46.4% at a viral load of <30,000 (232 specimens from 65 seropositive subjects). The assay was highly reproducible, with excellent correlation between duplicates and among three laboratories.

Aims: Data from drug treatment facilities, drug seizures and drug arrests suggest rapidly increasing methamphetamine use by adolescents in Thailand. However, limited quantitative data are available about the prevalence of its use or correlates of use. The purpose of our study was therefore to estimate the prevalence of methamphetamine use and to identify possible risk factors., Design: Cross-sectional survey using anonymous audio-computer-assisted self-interview and urine specimen analysis., Setting: Chiang Rai Province, Thailand., Participants: 1725 students, 15-21 years of age (893 male and 832 female) attending one of three vocational schools in Chiang Rai Province., Findings: Three hundred and fifty male and 150 female students reported a history of having ever used methamphetamine. In addition, 128 male and 49 female students had positive urine test results, indicating recent methamphetamine use; 27 of these students denied having ever used methamphetamine. According to history, urine test, or both, 41.3% of male students and 19.0% of female students used methamphetamine. In multivariate analysis, methamphetamine use was highly correlated with the use of other substances, sexual activity, peer pressure, positive attitudes toward methamphetamine, and absence of a family confidant., Conclusions: Methamphetamine use is common among adolescent students in northern Thailand. Demographic, behavioral and psychosocial correlates of methamphetamine use identified in this study may be helpful for the design and implementation of preventive interventions.

Most HIV surveillance has been performed through serologic surveys in relatively stable, accessible populations. Similar surveillance, with or without counseling and testing, in populations that are hard-to-reach, presents logistical challenges, including the selection of laboratory testing strategy and algorithm. The advent of rapid serologic assays for HIV now allows for on-site testing, including confirmatory testing, and rapid provision of test results and counseling. The possibility of only a single contact makes repeat sampling, which current diagnostic testing recommendations include, difficult. To address the logistical complexities in surveillance in hard-to-reach populations and the increased availability of rapid tests, we propose adapting the testing strategies for HIV of the World Health Organization/the joint United Nations Programme on HIV/AIDS in order to facilitate this surveillance, including, where carried out, the provision of test results back to individuals. The choice of enzyme-linked immunosorbent assay (ELISA) versus rapid testing for these settings is discussed, as is the choice of specimen--blood, oral fluid, or urine. Three appendices summarize: (1) test algorithms for the various testing strategies; (2) advantages and disadvantages of ELISA and of rapid test formats, and (3) the characteristics and status of currently available rapid HIV tests. We also discuss the potential application of the recently developed 'detuned' methodology for estimating HIV incidence in hard-to-reach populations.

Many studies have shown a positive association between both migration and temporary expatriation and HIV risk. This association is likely to be similar or even more pronounced for forced migrants. In general, HIV transmission in host-migrant or host-forced-migrant interactions depends on the maturity of the HIV epidemic in both the host and the migrant population, the relative seroprevalence of HIV in the host and the migrant population, the prevalence of other sexually transmitted infections (STIs) that may facilitate transmission, and the level of sexual interaction between the two communities. Complex emergencies are the major cause of mass population movement today. In complex emergencies, additional factors such as sexual interaction between forced-migrant populations and the military; sexual violence; increasing commercial sex work; psychological trauma; and disruption of preventive and curative health services may increase the risk for HIV transmission. Despite recent success in preventing HIV infection in stable populations in selected developing countries, internally displaced persons and refugees (or forced migrants) have not been systematically included in HIV surveillance systems, nor consequently in prevention activities. Standard surveillance systems that rely on functioning health services may not provide useful data in many complex emergency settings. Secondary sources can provide some information in these settings. Little attempt has been made, however, to develop innovative HIV surveillance systems in countries affected by complex emergencies. Consequently, data on the HIV epidemic in these countries are scarce and HIV prevention programs are either not implemented or interventions are not effectively targeted. Second generation surveillance methods such as cross-sectional, population-based surveys can provide rapid information on HIV, STIs, and sexual behavior. The risks for stigmatization and breaches of confidentiality must be recognized. Surveillance, however, is a key component of HIV and STI prevention services for forced migrants. It is required to define the high risk groups, target interventions, and ultimately decrease HIV and STI transmission within countries facing complex emergencies. It is also required to facilitate regional control of HIV epidemics.

Objectives: To describe epidemiologic patterns and trends in HIV infection in Vietnam from 1996 through 1999, and to summarize the national response to the epidemic., Methods: We reviewed nationwide HIV case reports, and we analyzed annual seroprevalence among different sentinel populations in 21 provinces, using the chi2 test for linear trend to assess trends in HIV prevalence. HIV prevention efforts were also reviewed., Results: Through 1999, 17,046 HIV infections, including 2947 AIDS cases and 1523 deaths had been reported in Vietnam. The cumulative incidence rate for the country was 22.5 per 100,000 population. Injection drug users (IDUs) represented 89.0% of all those for whom risk was reported before 1997 and 88.0% in the period 1997 to 1999. In 1999, HIV prevalence rates among IDUs ranged by province from 0% to 89.4%. Significantly increasing HIV trends among IDUs (p <.05) were found in 14 of the 21 sentinel provinces during 1996 to 1999. HIV prevalence among commercial sex workers (CSWs) ranged from 0% to 13.2%, increased significantly in 6 of 21 provinces. In 1999, prevalence among pregnant women, blood donors, and military recruits were 0.12%, 0. 20% and 0.61%, respectively. Major prevention activities include mass information; peer education and outreach among groups at increased risk; availability of low-cost syringes and condoms through pharmacies; needle exchange pilot projects; widely available treatment for sexually transmitted diseases; antibody screening of blood for transfusion; and free medical treatment at government hospitals., Discussion: The HIV epidemic continues to evolve rapidly, intensifying among IDUs and increasing among CSWs. Serosurveillance indicators of HIV in the population at large continue to indicate the relatively slow extension beyond those at highest risk. Immediate, intensive preventions in high-risk groups may decelerate expansion to the broader population.

To better characterize the virus isolates associated with the HIV-1 epidemic in Uganda, 100 specimens from HIV-1-infected persons were randomly selected from each of two periods from late 1994 to late 1997. The 200 specimens were classified into HIV-1 subtypes by sequence- based phylogenetic analysis of the envelope (env) gp41 region; 98 (49%) were classified as env subtype A, 96 (48%) as D, 5 (2.5%) as C, and 1 was not classified as a known env subtype. Demographic characteristics of persons infected with the two principal HIV-1 subtypes, A and D, were very similar, and the proportion of either subtype did not differ significantly between early and later periods. Our systematic characterization of the HIV-1 epidemic in Uganda over an almost 3-year period documented that the distribution and degree of genetic diversity of the HIV subtypes A and D are very similar and did not change appreciably over that time.

While basic guidelines on HIV prevention in emergencies have been available for several years, international agencies involved in the provision of health services have not placed sufficient priority on the prevention of the human immune deficiency virus (HIV) and other sexually transmitted infections (STIs) in complex emergencies. This paper reviews the factors that may increase the risk of HIV transmission in populations affected by complex emergencies and outlines recommendations for research and programmes. Research into the most appropriate methods of carrying out HIV surveillance and interventions in these settings is needed. In the post-emergency phase programmes need to be far more extensive than those offered under the Minimal Initial Services Package (MISP). While the potential for stigmatization represents an important constraint, there is a need to prioritize HIV/STI interventions in order to prevent HIV transmission in emergency-affected populations themselves, as well as to contribute to regional control of the epidemic.

Objective: To assess whether HIV-2 infection protects against HIV-1 infection by comparing the rate of HIV-1 seroconversion among HIV-negative and HIV-2-seropositive women followed in a cohort study in Abidjan, Côte d'Ivoire., Design: Prospective cohort study, Methods: HIV seroconversion was assessed in 266 HIV-seronegative, 129 HIV-1-seropositive, and 127 HIV-2-seropositive women participating in a closed cohort study of mother-to-child transmission of HIV conducted during 1990-1994. Participants were seen every 6 months, and blood samples were obtained. All blood samples were screened for HIV antibodies by enzyme immunoassay (EIA) and confirmed by line immunoassay (LIA) and Western blot. Among women who were HIV-seronegative at enrolment, seroconversion was defined as new EIA-reactivity confirmed on LIA and Western blot. Among HIV-1- or HIV-2-seropositive women, seroconversion to dual reactivity was defined as new dual reactivity on the LIA that was confirmed by reactivity on both HIV-1- and HIV-2-monospecific EIA., Results: Five HIV-seronegative women became HIV-1-seropositive [seroconversion rate, 1.1 per 100 person-years; 95% confidence interval (CI), 0.3-2.5), and none became HIV-2-seropositive. No HIV-1-seropositive women became HIV-1/2 dually reactive, whereas six HIV-2-seropositive women acquired HIV-1 seroreactivity and thus became HIV-1/2 dually reactive (seroconversion rate 2.9 per 100 person-years; 95% CI, 1.1-6.3). HIV-2-seropositive women were more likely to acquire HIV-1 seroreactivity than were HIV-seronegative women (rate ratio, 2.7; 95% CI, 0.7-11.2), but this difference was not statistically significant (P>0.15)., Conclusion: HIV-2 infection does not appear to protect against HIV-1 infection.

The AIDS Information Center (AIC) was established in Kampala, Uganda in 1990 in response to increasing interest by members of the general public who wished to know their HIV serostatus. By 1996, >300,000 clients had been seen. HIV serologic testing was performed at a central laboratory and results reported back to AIC after 2 weeks. Approximately 25% of clients failed to learn their HIV serostatus as a result of failure to return or late arrival of results. To address these issues, AIC carried out an evaluation of 3 rapid HIV assays, Sero-Strip, SeroCard, and Capillus, against a standard criterion to identify a testing algorithm that could be used as an on-site confirmatory testing strategy. The study was carried out over a period of 5 working days and 325 clients were seen. An algorithm was identified, which gave no indeterminate results with unambiguously positive or negative specimens, which was 100% sensitive and specific, and which could be integrated with minimal disruption into existing counseling procedures. All clients left AIC knowing their HIV serostatus and having spent <2 hours at the Center. The results of this evaluation demonstrate that "same-day" results can be provided in counseling and testing settings without compromising the quality of counseling or the accuracy of HIV testing.

We developed a method for large-scale screening of HIV-1 genotypic variation based on DNA probe hybridization. Nested PCR amplifications were performed to generate fragments in the env C2-V3 region and also in the gp41 region, which encompasses the immunodominant domain. The proviral DNA sequences were derived from 68 samples and phylogenetically analyzed. For comparison, the C2-V3 fragment was used in DNA probe hybridization to rapidly determine the infecting HIV subtype. The hybridizing probes were designed on the basis of the two most prevalent subtypes in Uganda, A and D. The results were compared to evaluate the feasibility of using this hybridization method for large-scale genotypic screening. Sequence analysis of the 68 amplified PCR fragments showed that 39 were subtype A and 29 were subtype D. The results of DNA hybridization to the amplified products with A and D subtype-specific probes were more than 90% concordant with the subtypes determined by sequence analysis. Our findings suggest that probe hybridization with subtype-specific probes is effective for large-scale screening of HIV-infected populations. Application of this method will significantly reduce the time needed for large, population-based investigations.

Objective: Previous data, based on a small sampling of convenience, reported subtypes A, B, C, D, and G in Uganda, but neither the extent nor the proportion of these subtypes could be evaluated. To establish correctly the prevalence and distribution of HIV-1 subtypes, we analysed viral clades in 739 HIV-1-seropositive specimens from different areas of Uganda., Methods: Blood specimens from 1100 patients were collected in five districts of Uganda. Within this collection, 929 HIV-1-seroreactive samples underwent analysis of viral DNA, and 739 were selected for further subtyping in env or pol regions., Results: Using a combination of subtype A- and D-specific probes to C2-V3 region and DNA sequencing, HIV-1 env subtypes were determined in 594 specimens: 341 were of subtype A (57.4%), 250 of subtype D (42.1%), and three of subtype C (0.5%). Sixty-two samples showed reactivity with both probes, suggesting potential mixed infections, cross-reactivity to probes, or possibly other subtypes. Subsequent sequence analysis of 19 randomly selected specimens revealed subtypes A (n = 4), D (n = 12), and C (n = 3). Sequence analysis of the 27 samples chosen from the remaining 83 samples, which could be amplified only with viral gp41 or protease gene primers, classified them as subtypes A (n = 13) and D (n = 14). No significant clinical, demographic, or geographic differences were found between HIV-1 infections with viruses of subtypes A and D, despite considerable genetic diversity within these clades., Conclusions: This is the first major population-based study of the prevalent HIV-1 strains in an African country selected for vaccine trials. The subtyping methods we describe should be of use to investigators seeking to conduct large-scale screening for HIV variants in other populations.

The discovery of highly divergent strains of human immunodeficiency virus (HIV) not reliably detected by a number of commonly used diagnostic tests has underscored the need for effective surveillance to track HIV variants and to direct research and prevention activities. Pathogens such as HIV that mutate extensively present significant challenges to effective monitoring of pathogens and to disease control. To date, relatively few systematic large-scale attempts have been made to characterize and sequence HIV isolates. For most of the world, including the United States, information on the distribution of HIV strains among different population groups is limited. We describe herein the implications resulting from the rapid evolution of HIV and the need for systematic surveillance integrated with laboratory science and applied research. General surveillance guidelines are provided to assist in identifying population groups for screening, in applying descriptive epidemiology and systematic sampling, and in developing and evaluating efficient laboratory testing algorithms. Timely reporting and dissemination of data is also an important element of surveillance efforts. Ultimately, the success of global surveillance network depends on collaboration and on coordination of clinical, laboratory, and epidemiologic efforts.

Objectives: To date, HIV spread in China has occurred principally among injecting drug users (IDU) in remote border regions of Yunnan province. We therefore sought to better understand the risks for and prevalence of HIV infection among drug users in parts of China outside Yunnan province., Methods: A behavioral survey of drug use and AIDS-related knowledge was conducted among all consenting drug users who entered treatment from 1 November to 31 December 1993 in seven provincial drug detoxification centers outside Yunnan province. After giving verbal informed consent, all drug users were tested for HIV., Results: Of the 1293 study participants, 207 (16%) reported injecting drugs. The proportion of IDU among all drug users varied widely by region, from 1% in Sha'anxi and Gansu provinces in the northwest region to 58% in Guangxi province in the south. IDU were more likely than non-IDU to be single and unemployed or self-employed, but did not differ in other demographic aspects. Among all drug users, 2% reported sharing needles without cleaning equipment, while 5% shared with some cleaning. Although 1060 (82%) drug users had heard of AIDS and most knew about its sexual (79%), parenteral (77%), and perinatal (60%) modes of transmission, many had misconceptions about its spread by casual contact. Of the 207 IDU tested for HIV, none were HIV-positive (95% confidence interval, 0--1.4)., Conclusion: The absence of HIV infections detected in this study suggests that the prevalence of HIV is currently low among IDU in China outside the Yunnan province. However, the behavior of these IDU puts them at high risk for HIV infection. Prevention efforts are needed to prevent the spread of HIV among IDU throughout China and to avoid the experience of neighboring countries in Asia.

The CDC Family of Surveys is a national serologic surveillance system set up to characterize the extent of human immunodeficiency virus (HIV) infection in the United States. The now Centers for Disease Control and Prevention (CDC) and participating State and local health departments began the system in 1987. HIV seroprevalence data are collected by unlinked (anonymous) surveys of particular components of the population that include childbearing women; clients of sexually transmitted disease clinics; injecting drug users; tuberculosis patients; and several special populations, such as adolescents, prisoners, and homeless persons. The data obtained have been used extensively on both national and local levels to assist HIV-prevention programs. Data from the surveys have been used to identify specific demographic groups at risk for HIV infection so that health education programs may be planned and made available to them in clinical settings. Local serosurvey results have been used in planning and implementing prevention programs and in planning health services for HIV-positive persons. The completeness, or coverage, of HIV counseling and testing programs has been evaluated by comparing seroprevalences among clients tested voluntarily with those tested in the unlinked survey. Survey data are used in formulating recommendations and standards of care for health practitioners, in allocating resources, and in carrying out long-range planning for HIV prevention and treatment services for at-risk groups. Such data are essential to the decision-making process in forming public health policy and recommending practices involving the HIV epidemic.

The Centers for Disease Control and Prevention has developed guidelines for determining HIV seroprevalence among patients seeking medical care at acute-care hospitals. The guidelines enable hospital staff members to perform a simple, rapid, and inexpensive survey to determine seroprevalence among the patient population, protecting the anonymity of those who are tested. The guidelines are based on national experience with large-scale anonymous, unlinked HIV serosurveys. The data from a rapid assessment survey are particularly useful for evaluating the need to provide routine, voluntary HIV counseling and testing and treatment for HIV infection. Beyond that, such data can be used in targeting education efforts, in reinforcing the use of appropriate universal precautions, in resource allocation, and in determining the need for further studies of HIV infection among the population in the hospital catchment area.

Objective: The testing of neonatal blood specimens dried on filter paper for maternal HIV antibodies, using an enzyme immunoassay (EIA) with confirmation of repeatedly reactive specimens by immunoblot (IB), was first described in 1987. It has been used to conduct large, unlinked, anonymous HIV seroprevalence surveys for surveillance of HIV in child-bearing women in several countries. We directly assessed the sensitivity and specificity of this combination of tests to detect maternal HIV antibodies., Setting: Serum samples obtained from mothers delivering at a major hospital in Kinshasa, Zaire were screened for HIV antibody using the rapid assay HIVCHEK., Design: Plasma from HIVCHEK-positive women and age-matched negative controls were tested by enzyme-linked immunosorbent assay (ELISA); repeatedly reactive specimens were confirmed by Western blot (WB). Two days after delivery, whole blood was obtained from each newborn by heel-stick, dried on filter paper, and tested by EIA. Repeatedly reactive specimens were confirmed by IB., Main Outcome Measure: The serologic status of neonatal filter-paper specimens was compared with that of corresponding maternal plasma., Results: The testing of neonatal filter-paper specimens using EIA, with confirmatory testing of repeatedly reactive specimens using IB, was 100.0% sensitive [of the 192 ELISA-positive and WB-positive maternal plasma specimens, 192 of the corresponding newborn filter-paper specimens were EIA-positive and IB-positive; 95% confidence interval (CI), 98.1-100]. The detection of maternal HIV antibodies was 99.6% specific using this combination of tests (of the 281 ELISA-negative or ELISA-positive but WB-negative maternal plasma samples, 280 of the corresponding newborn filter-paper specimens were EIA-negative or EIA-positive but IB-negative; 95% CI, 98.0-100)., Conclusions: Maternal HIV antibodies can be detected accurately by testing neonatal blood dried on filter paper, using EIA with confirmation of repeatedly reactive specimens by IB. This approach can facilitate the determination of HIV seroprevalence in child-bearing women in countries with neonatal screening programs, or where serum or plasma is difficult to obtain.

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.

Background and Methods: To evaluate the epidemiology of infection with human immunodeficiency virus type 1 (HIV-1) in selected urban communities in the United States, we instituted active surveillance at sentinel hospitals by anonymous testing of samples of blood specimens for HIV-1 antibody. To reflect better the rates of HIV-1 seroprevalence in the communities served by the sentinel hospitals, we excluded specimens from all patients with diagnoses that are often associated with HIV infection., Results: From January 1988 to June 1989, 89,547 specimens were tested at 26 hospitals in 21 cities. The overall rate of HIV-1 seroprevalence was 1.3 percent, but it ranged from 0.1 to 7.8 percent according to hospital (median, 0.7 percent). The age distribution of persons seropositive for HIV-1 was similar across hospitals and closely paralleled that of persons with the acquired immunodeficiency syndrome (AIDS). In areas of low seroprevalence, HIV-1 infections were highly concentrated among men. However, the male-to-female ratio (median, 7.0) decreased steadily with an increasing overall rate of seroprevalence (P less than 0.001); at the five hospitals with the highest rates of seroprevalence, the median male-to-female ratio was only 2.9. The median black-to-white ratio of HIV-1 seroprevalence was 1.8, but at hospitals with low rates of seroprevalence the rates in blacks and whites were nearly equal. At two hospitals in the communities with the highest prevalence of AIDS, 1.1 to 3.8 percent of adolescents 15 to 19 years old and 18 to 22 percent of all men 25 to 44 years old were seropositive for HIV-1., Conclusions: In these sentinel, urban populations there is tremendous variation in the rate of HIV-1 infection (over 70-fold). The very high seroprevalence at some sentinel hospitals indicates the need for routine screening for HIV-1 infection among some groups of patients, regardless of clinical presentation.

Human immunodeficiency virus, type 1 (HIV), seroprevalence studies are needed to determine the level and trends of HIV infection among women attending family planning, abortion, and prenatal care clinics in the United States. A review of published and unpublished studies showed that HIV seroprevalence among women attending women's health clinics was 0 to 2.6 percent, although the studies were difficult to compare because of differences in methodology. The Centers for Disease Control, in association with State and local health departments, has developed a standardized protocol to determine HIV seroprevalence among women attending women's health clinics in selected metropolitan areas. Blinded HIV serosurveys (serologic test results not identified with a person) are being conducted annually in selected sentinel clinics in order to obtain estimates of HIV seroprevalence unbiased by self-selection, as well as to monitor trends in infection among clients attending these clinics. In areas with high HIV seroprevalence, nonblinded serosurveys (in which clients voluntarily agree to participate) will be used to assess behaviors that may place women at increased risk of exposure to HIV. Data from the surveys can be used in developing age-specific and culturally appropriate AIDS educational materials, assessing the amount and type of counseling activities required, and evaluating acquired immunodeficiency syndrome (AIDS) prevention activities. The information will provide epidemiologic data to complement the results of other surveys in characterizing the scope of HIV infection among women of childbearing age in the United States.

Symptomatic tuberculosis (TB) can occur as an opportunistic disease in immunosuppressed persons who are infected with human immunodeficiency virus (HIV) and who have been previously infected with Mycobacterium tuberculosis. Increases in TB cases have occurred in areas which have reported large numbers of cases of the acquired immunodeficiency syndrome (AIDS), and a high proportion of these TB cases have been HIV seropositive. Therefore, increasing numbers of HIV-infected persons may be found in TB clinics and hospitals. HIV serologic surveys in TB clinics and hospitals providing clinical services to TB patients are needed to assess the local prevalence of HIV infection in TB patients and the consequent need for public health intervention to prevent further spread of HIV and TB infection. The Centers for Disease Control (CDC), in collaboration with State and local health departments, has initiated HIV surveillance of patients with confirmed and suspected TB in TB clinics and hospitals in the United States. Blinded (serologic test results not linked to identifiable persons) HIV seroprevalence surveys are conducted in sentinel TB clinics and hospitals that provide TB clinical services each year to obtain estimates of the level of HIV infection in TB patients and to follow trends in infection over time. Nonblinded (voluntary) surveys will also be conducted to evaluate behaviors that have placed TB patients at risk for or protected them against HIV infection. Data from these surveys will be used to target education and prevention and control programs for TB and HIV infection and to monitor changes in behavior in response to such programs.

Sharing of equipment used to inject illicit drugs intravenously is a risk factor for human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS). Systematic surveillance of HIV infection among intravenous drug users (IVDUs) in the United States is essential to monitor the HIV epidemic and to target and evaluate prevention programs for IVDUs and their partners. The most accessible segment of the largely covert population of IVDUs are those in drug treatment programs. In collaboration with State and local health departments and drug abuse treatment agencies, the Centers for Disease Control is conducting blinded (serologic test results not linked to identifiable persons) and nonblinded (in which clients voluntarily agree to participate) surveys of IVDUs entering drug treatment in 39 U.S. metropolitan areas. The same protocol is used in all participating drug treatment centers. Blinded surveys will be carried out annually to determine HIV seroprevalence rates in eligible IVDUs entering drug treatment and to monitor trends over time. Each year, nonblinded surveys of IVDUs entering drug treatment will assess self-reported drug use and sexual behaviors to help design educational interventions and to detect changes in behavior over time. This sentinel surveillance system, using a standardized methodology, will provide the best national and regional data available on the seroprevalence of HIV among IVDUs and the relationships of drug use, sexual behaviors, and HIV serologic status of IVDUs.

The Centers for Disease Control, in cooperation with State and local health departments, is conducting human immunodeficiency virus, type 1 (HIV), seroprevalence surveys, using standard protocols, in sexually transmitted disease (STD) clinics in selected metropolitan areas throughout the United States. The surveys are blinded (serologic test results not identified with a person) as well as nonblinded (clients voluntarily agreeing to participate). STD clinics are important sentinel sites for the surveillance of HIV infection because they serve persons who are at increased risk as a result of certain behaviors, such as unprotected sex, homosexual exposure, or intravenous drug use. HIV seroprevalence rates will be obtained in the sentinel clinics each year so that trends in infection can be assessed over an extended period of time. Behaviors that place clients at risk for infection, or protect against infection, are being evaluated in voluntary, nonblinded surveys to define groups for appropriate interventions and to detect changes in response to education and prevention programs. Although inferences drawn from the surveys are limited by the scope of the clinics and clients surveyed, HIV trends in STD clinic client populations should provide a sensitive monitor of the course of the acquired immunodeficiency syndrome (AIDS) epidemic among persons engaging in high-risk sexual behaviors.

A seroprevalence survey of human immunodeficiency virus (HIV) among childbearing women is being conducted in 43 States and Territories as one of the family of HIV seroprevalence surveys. This blinded survey, in which serologic test results are not linked to identifiable persons, uses neonatal dried blood specimens on filter paper to test for maternal antibodies to HIV. This survey provides relatively unbiased estimates of prevalence of HIV infection in the population of women delivering live children during given survey periods, by month or quarter of delivery, geographic area, and demographic subgroup. This objective will be met while protecting the integrity and efficient conduct of neonatal screening programs and ensuring patient anonymity. Information from this survey will be used to (a) assess the levels and trends of HIV infection in women and infants, (b) help develop and evaluate prevention programs, and (c) project the number of women and children who will develop HIV infection and the acquired immunodeficiency syndrome (AIDS) and will require health care and social services in the future.

Six cases of cutaneous myiasis occurred in three groups of visitors to Guatemala between February and May 1978. Attack rates ranged from 12% to 50%. Furuncular lesions were generally multiple and involved both exposed and usually unexposed areas of the body. Parasitic fly larvae recovered from two patients were identified as the botfly, Dermatobia hominis. Botfly infestation is endemic in areas of Central and South America and is acquired indirectly through the bite of carrier arthropods, including mosquitoes. Although reports of cases in North Americans visting endemic areas are rare, the condition is probably much more common in such persons than it is currently believed to be. A history of travel to Central or South America should suggest the diagnosis.

Chloroquine pressure was applied over a 22 month period on a somewhat isolated, malarious rubber estate by examination of residents at 4-week intervals and treatment of parasitaemias with chloroquine. During this time the monthly attack rate for P. falciparum rose four-fold to an average of nearly 18% per month, while that of P. vivax remained relatively constant at about 8%. Eight in vivo chloroquine resistance studies, which allowed both detection of late recrudescing R-I resistance and estimation of the risk of reinfection, showed an apparent rise in the drug resistance rate, from 12% to 20% prior to the study to the range of 40-50%. Virtually all resistance encountered was R-I in nature. There was no convincing evidence of chloroquine resistance among 148 tested P. vivax infections.