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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.

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.

The U.S. sentinel hospital surveillance system for human immunodeficiency virus (HIV) infection includes approximately 40 short-stay hospitals located in 31 metropolitan areas in the United States and Puerto Rico. Several hospitals began testing in late 1986, and additional sentinel hospitals have since been recruited. At each sentinel hospital, anonymous, unlinked testing for antibody to HIV is conducted monthly on 300 blood specimens, selected systematically and stratified by age of the patient. Specimens are excluded from patients whose reason for hospital visit on that occasion was for a medical condition associated with HIV infection or with risk factors for HIV infection, in order to limit the expected overrepresentation of HIV-infected persons among hospital patients compared with the general catchment population of the hospital. The incidence of acquired immunodeficiency syndrome (AIDS) in metropolitan areas with sentinel hospitals has been approximately twice the incidence of AIDS in the entire United States. However, while absolute levels of HIV seroprevalence should therefore be interpreted with caution, trends in the age-, sex-, and race-specific HIV seroprevalence at sentinel hospitals likely reflect trends in the communities served by the hospitals. Although concentrated in areas disproportionately affected by AIDS, sentinel hospitals will contribute seroprevalence data over time that reflect the impact of HIV infection across all age and behavioral risk groups. Sentinel hospitals will also constitute a key surveillance system to help integrate the age group-specific and risk group-specific findings from other activities in the CDC family of seroprevalence surveys.

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.

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.

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.

During 1987-89, the Centers for Disease Control (CDC), in collaboration with State and local health departments, other Federal agencies, blood collection agencies, and medical research institutions, implemented a national sentinel surveillance system for human immunodeficiency virus (HIV) infection. This ongoing surveillance system, known as the CDC family of HIV seroprevalence surveys, uses standardized survey and HIV serologic testing procedures in a group of sentinel populations from geographically diverse metropolitan areas, States, and Territories of the United States. As of September 1989, sentinel surveillance for HIV infection was being conducted in 41 States, Puerto Rico, and 39 metropolitan areas, including the District of Columbia. Information from this system complements AIDS surveillance data to assist health officials to direct resources and develop strategies for HIV prevention and health-care programs.

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.

Blood donors make up the largest group in the United States that is tested for human immunodeficiency virus, type 1 (HIV) antibody. The blood donor population is ideal for detecting and quantifying uncommon or unrecognized modes of HIV transmission in the general population because persons at known risk for HIV infection are excluded from donating blood. The national HIV surveillance program consists of a centralized computer database of information on all donations at selected American Red Cross blood centers, which together account for about a quarter of the blood supply, and all donations at 20 regional blood centers where seropositive blood donors are interviewed to evaluate their risk factors for HIV infection and to determine their epidemiologic characteristics and motives for donation. Trends in HIV prevalence and incidence within specific demographic subgroups are determined for first-time and repeat donors. Combining the trends with HIV-risk profile data from seropositive donors provides a rate for HIV seropositive donors with no identified risk. Epidemiologic and behavioral data from seropositive donors will help in the development and evaluation of future donor deferral strategies.

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.

In August and September 1977 a discrete cluster of 27 serologically or pathologically confirmed cases of Legionnaires' disease, plus six highly presumptive cases were identified in the area of Kingsport, Tennessee. Three patients died. Most patients manifested severe pneumonia and fever; no mild or asymptomatic disease forms were recognized despite intensive case-finding efforts. Illness was epidemiologically associated with residing, visiting, or working in one geographic area of Kingsport, residence there being the factor most strongly associated. Although the attack rate for area residents was 0.64%, the randomly determined prevalence of serologic reactors was 5.2%, which is not significantly different from that in a nonimplicated control neighborhood. The epidemic did not correlate temporally with any identified environmental or demographic event. No source of the bacterium was found either by a detailed case-control study of area associations or by bacterial isolation from sentinel guinea pigs or environmental specimens. There was no evidence of person-to-person spread.

A comprehensive, multifaceted approach to HIV surveillance is needed to provide the information necessary for public health management and policy. Because HIV infection is not readily or uniformly ascertained, survey methods and sentinel surveillance approaches must be used. At least some of the surveys must be blinded, that is, anonymous and unlinked to identifiable persons, to avoid the uninterpretable impact of self-selection bias that could lead to both significant underestimates and occasional overestimates of HIV prevalence. Other surveys must be nonblinded, with careful interviews of volunteer participants to evaluate risk factors for HIV infection. These various surveys must continue over time to evaluate trends in infection. A comprehensive family of complementary HIV surveys and studies and a national household-based HIV seroprevalence survey have been undertaken by the Public Health Service in collaboration with other Federal agencies, State and local health departments, blood collection agencies, and medical research institutions. These projects focus on accessible segments of the general population, childbearing women, persons at high risk for HIV, and persons in special settings such as prisons and colleges. This comprehensive surveillance approach will help monitor the levels and trends of HIV infection in the United States and help prioritize, target, and evaluate HIV prevention activities.

A cohort of 62 persons living in a malaria-endemic area was examined by serology and by blood film 14 times over a 56-week period. Serologic responses (indirect hemagglutination test) of the group as a whole reflected the malaria transmission as determined by blood slide examination. The serologic responses of individuals showed titer changes that were not always consistent with blood slide results. The use of chloroquine may have modified the host's immune response.

Planning for health and social services and for prevention programs requires predicting the number of AIDS cases likely to be diagnosed during the next several years and estimating the prevalence of HIV infection. Extrapolating from recent AIDS incidence data, we estimate that 365,000 AIDS cases will be diagnosed in the United States through 1992 (68% prediction interval, 205,000 to 440,000). Both recent HIV seroprevalence surveys and historical AIDS incidence are consistent with the U.S. Public Health Service estimate that 1.0 to 1.5 million persons in the United States are now infected with human immunodeficiency virus (HIV). Although current estimates of future AIDS cases and of current prevalence of HIV infection are somewhat uncertain, better statistical estimation procedures are being developed, and current surveys will provide additional data on HIV prevalence in the United States within the next several years.

Attempts to induce acquired resistance in Lymnaea rubiginosa snails against the echinostomes Echinostoma audyi and Hypoderaeum dingeri by means of irradiated miracidia were unsuccessful, although Lie and coworkers using similar methods had recently sensitized Biomphalaria glabrata against Echinostoma lindoense (1975a). In contrast to the B. glabrata-E. lindoense system, in Lymnaea rubiginosa the amebocytic response to irradiated parasites was slow: irradiated E. audyi sporocysts were encapsulated 15 to 28 days and H. dingeri sporocysts 20 to 27 days postexposure. No obvious enlargement of the amebocyte-producing organ was seen. No resistance was demonstrable to subsequent homologous challenge. Development of acquired resistance to a trematode infection in snails may be related to the speed with which the snails destroy the irradiated sporocysts.

Many of the conditions no doubt have already improved in those areas where international relief efforts are under way. The comments made here are based on observations by my colleagues and myself during the emergency phase of the famine and refugee crises and perhaps should be considered more as lessons learned that are better applied to newly emerging situations than to those relief efforts already in progress. In summary, the highest priority emergency health requirements identified during the current crisis have been, in my opinion, the provision of food and supplementary and therapeutic feeding, measles immunization, vitamin A prophylaxis, and oral rehydration therapy, plus the two management issues--rapid needs assessment with continued monitoring and adequate allocation of resources to prevention and control activities. One final note--from discussions with colleagues who were involved in the 1973-74 drought and famine in Africa, this crisis appears to be a repeat. A comprehensive, long-term approach would be beneficial so that these emergency responses are no longer necessary.

The indirect hemagglutination test was used to measure malaria antibody levels in residents of an endemic area of Malaysia. Blood specimens were collected at 4-week intervals for a year. Seropositivity rates increased with age and number of episodes of malaria in young children. Although antibody levels were variable, titers tended to rise with parasitemia and fall in the absence of detected parasites. In general, the serologic indices tended to reflect the parasitologic findings.

Interviews and physical examinations for filarial disease were conducted in Howrah near Calcutta, West Bengal, India, in a study area where long term quantitative entomological studies have disclosed high intensity, year round exposure to Wuchereria bancrofti. Little elephantiasis or other serious filariasis-related disease was noted, but half the males over 20 years of age had genital lesions of various types. Ninety-two percent of households had at least one resident with microfilaremia or presumptive clinical evidence of filarial disease.

In August and September 1978, an outbreak of Legionnaires' disease occurred in Memphis, Tennessee. Of the 44 ill, 39 had been either patients, employees, visitors, or passers-by at one Memphis hospital (Hospital A) during the 10 days before. Assuming an incubation period of between two and 10 days, the onset of cases correlated precisely with the use of Hospital A's auxiliary air-conditioning cooling tower. L. pneumophila was recovered from two samples of water from the tower. Infection appeared to have occurred both outside and within the hospital. A significant association was demonstrated between acquisition of Legionnaires' disease and prior hospitalization in those areas of Hospital A that received ventilating air from air intakes near the auxiliary cooling tower. Tracer-smoke studies indicated that contaminated aerosols from the tower could easily reach these air intakes, as well as the street below, where four passers-by had been before they contracted Legionnaires' disease. This represents a common-source outbreak in which the source of L. pneumophila infection and airborne transmission were identified.

In vivo chloroquine resistance surveys, which allowed for detection of late recrudescing RI resistance, were conducted in three regions of Peninsular Malaysia, which were previously not recognized as having appreciable drug resistance. Among the 485 Plasmodium falciparum infections tested resistance rates ranged locally from 20% to 67% in those with parasitaemias over 1,000 per mm3, and 5% to 59% in all parasitaemias. The region found to have the most serious resistance was western Pahang. In one study a combination of chloroquine and pyrimethamine proved no more efficacious than chloroquine alone. Most of the resistance encountered was the late recrudescing RI type. There was no apparent correlation between drug resistance and Anopheles balabacensis as this species was not found despite intensive collections in two of the three main regions. There was no evidence of resistance among the 222 P. vivax and 35 P. malariae infections also tested.