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In a statewide survey of 856 Iowa municipal drinking water supplies in 1986-1987 the Rathbun rural water system was found to contain elevated levels of triazine herbicides. Rates of low birth weight, prematurity, and intrauterine growth retardation (IUGR) in live singleton births during the period 1984-1990 by women living in 13 communities served by the Rathbun water system were compared to other communities of similar size in the same Iowa counties. The Rathbun communities had a greater risk of IUGR than southern Iowa communities with other surface sources of drinking water (relative risk = 1.8; 95% CI = 1.3, 2.7). Multiple linear regression analyses revealed that levels of the herbicides atrazine, metolachlor, and cyanzinc were each significant predictors of community IUGR rates in southern Iowa after controlling for several potentially confounding factors including maternal smoking and socioeconomic variables. The association with IUGR was strongest for atrazine, but all three herbicides were intercorrelated and the independent contributions of each to IUGR risk could not be determined. We conclude that communities in southern Iowa with drinking water supplies contaminated with herbicides have elevated rates of IUGR compared to neighboring communities with different water supplies. Because of the limitations of the ecologic design of this study, including aggregate rather than individual measures of exposure and limited ability to control for confounding factors related to source of drinking water and risk of IUGR, a strong causal relationship between any specific water contaminant and risk of IUGR cannot yet be inferred. The association between the water supplied to the Rathbun communities and the increased risk of IUGR should be considered a preliminary finding that needs to be verified by more detailed epidemiologic studies.

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We evaluated the EBV Combi Test (Virion) in serum samples from 574 children with a clinical presentation suggestive of infectious mononucleosis (IM) and compared its performance with several other EBV serological tests. Out of 574 sera 66 gave an acute IM pattern, 406 gave a past infection pattern and 102 were found negative in the EBV Combi Test. Positive VCA IgM and VCA IgG IFA results, in the absence of EBNA antibodies, were found in 62 cases in which the EBV Combi Test gave an acute IM pattern. In addition, 4 to the 574 tested sera gave an acute positive result in the EBV Combi Test (two of them were VCA IgM positive and the other two VCA IgM negative but also EBNA negative). None of these four sera were CMV IgM or Toxoplasma gondii IgM positive. The heterophile antibody test was positive in only 28, and VCA IgM EIA positive in 44 of the 62 IM cases. These data confirm the necessity for an EBV serological diagnosis in children where the clinical diagnosis of EBV infectious mononucleosis must be confirmed or ruled our.

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OBJECTIVE: To determine the risk of lead poisoning among children enrolled in day care centers with elevated environmental lead burdens. DESIGN: Survey. SETTING: Six day care centers on properties owned by a major state-supported university. PATIENTS AND OTHER PARTICIPANTS: One hundred fifty-five of 234 eligible children (mean age, 4.8 years) enrolled in these centers were screened by questionnaire for risk factors of lead exposures. Blood samples for lead levels were also obtained. Observations of day care activities relative to lead exposure risks were recorded. Analyses of lead levels in paint, dust, and/or soil samples at the six centers were obtained. MAIN OUTCOME MEASURES: Prevalence of elevated blood lead levels and associated behavioral risk factors for lead exposure in children attending day care centers. RESULTS: Elevated levels of lead in paint (2.4% to 40% lead) were present in all day care facilities. Three day care centers had elevated lead levels in windowsill dust (62,000 to 180,000 micrograms [corrected] of lead per square meter) or soil (530 to 1100 mg of lead per kilogram): Questionnaires documented low risk for lead exposure to children in the home environments. Direct observations in the day care setting revealed optimal supervision and hygiene of the children. Blood lead levels were less than 0.5 mumol/L (10 micrograms/dL) in all but one of the 155 children screened. CONCLUSIONS: Children attending day care centers with high environmental lead burdens need further documentation of blood lead levels, at-risk behaviors, and lead exposure risks in the home environments as an adjunct to the instigation of lead abatement procedures at the day care centers.

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OBJECTIVE: To identify commercial baby food varieties high in nitrate content using ion chromatography and compare the health risk associated with the consumption of high-nitrate water and high-nitrate commercial baby food. DESIGN: Ion chromatographic determination of nitrate concentration in a variety of commercial baby foods. SETTING: University Hygienic Laboratory, University of Iowa College of Medicine, Iowa City. PATIENTS: None. RESULTS: Commercial baby foods with nitrate levels higher than 45 ppm include mixed vegetables, bananas, carrots, garden vegetables, spinach, green beans, and beets. The amount of nitrate in one 113-g (4 oz) jar of beets, for example, is equivalent to the amount of nitrate in nearly 5.5 L of water at 45 ppm nitrate. CONCLUSIONS: A controlled clinical trial is needed to clarify how consuming high-nitrate foods correlates with methemoglobin levels in infants younger than 6 months.

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Iowa has participated in the national survey for the prevalence of HIV infection in childbearing women since July of 1989. As of February 1992, blinded testing for antibodies to HIV has been performed on blood spot specimens from 100,717 newborns. Of this number, 14 were confirmed as positive by Western blot. In the Iowa survey the prevalence of HIV infection in childbearing women was 0.14/1000 or 1/7000. This is similar to the prevalence that was observed for PKU in newborns during this time period. However, assuming only 30% of mothers transmit HIV to their babies, the predicted prevalence of HIV infection in Iowa newborns is 1/23,000. Certainly HIV disease is a public health concern with a frequency in Iowa mothers similar to that of other diseases screened for in the Iowa program. HIV meets the remaining WHO criteria for newborn screening, as well: the HIV screening test is simple and reliable and has a low incidence of false-positive and false-negative results; confirmatory testing, counseling, and medical care are available; the quality and length of life of affected individuals are improved by treatment; and data show that early diagnosis and treatment result in a cost advantage to society. The major obstacle to the addition of HIV testing to a newborn screening program is obtaining informed consent without jeopardizing program effectiveness.

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The complement fixation (CF) procedure has played a significant role in the diagnosis of infectious diseases for almost a century. It has accomplished this by functioning in serodiagnosis and by antigen identification particularly in clinical virology. Although it has been replaced by newer, more sensitive and rapid techniques for serodiagnosis, the CF assay is still important as a reference standard for clinical laboratories.

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A blinded survey of HIV infection in childbearing women is being conducted in 43 states and territories. After one year of participation in the survey, 6 of 37,846 women bearing live children in Iowa were found to be infected with HIV.

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Serum specimens which originally exhibited a narrow (indeterminate) 24-kilodalton core protein (p24) or p24/p55 pattern of reactivity with human immunodeficiency virus (HIV) in the Western blot (immunoblot) test were studied to gather information on antibody specificity. A total of 12 specimens were initially reevaluated with an indirect immunofluorescence assay (IFA), three enzyme-linked immunosorbent assays (ELISAs), and Western blot analyses. Five of the specimens were IFA positive and contained anti-gp160/gp120 antibodies which were observed only when an HIV Western blot antigen rich in gp160 and gp120 was used. The remaining seven serum specimens were nonreactive by IFA and showed variable reactivity in HIV antibody ELISAs. The specimens did not cross-react with core antigens for human T-cell leukemia virus types 1 and 2 or contain detectable levels of HIV p24 antigen. The p24/p55 reactivity of six of the seven indeterminate specimens could be reduced or eliminated by preincubating the specimens with disrupted, HIV-infected H9 cells but not with uninfected H9 cells. The six specimens also exhibited discernible reactivity with recombinant HIV p24 antigen. When an additional 23 indeterminate specimens were assayed, all of the serum specimens were nonreactive by IFA while 65% (15 of 23) showed various degrees of reactivity with the recombinant p24 protein. There was no indication that any of the HIV core antibody reactivity was caused by HIV infection. Indeterminate results for five patients with specific p24 reactivity, who were retested after a period of weeks or months, remained indeterminate for HIV antibody with no significant change in ELISA or Western blot reactivity.

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From January 1 to April 30, 1986, all individuals entering the Iowa prison system were tested for antibody to the human immunodeficiency virus (HIV). Sera were collected on 363 newly incarcerated inmates, 389 inmates returning to prison, and 107 forensic psychiatric patients. Three of the 859 serum samples (0.3 per cent) tested during this study were reactive by ELISA (enzyme-linked immunosorbent assay) testing, but none reactive by the Western blot. Analysis for AIDS risk factors included a high prior IV-drug use rate (22-50 per cent) and a low admitted homosexuality rate in a predominantly young white male population.

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The SUDS Toxo test (MUREX Corp., Norcross, Ga.) was compared with the indirect hemagglutination test (IHA) and the indirect fluorescent-antibody test (IFA) by examining 404 serum specimens, including 64 (15.8%) specimens with IFA titers of greater than or equal to 1:2. When SUDS was compared with IHA, sensitivity (96.4%), specificity (97.9%), and negative predictive value (99.4%) indicated that there were similar reactivities between the two tests. When an IFA titer of greater than or equal to 1:16 was considered significant and IHA and SUDS were compared with IFA, IHA was slightly less sensitive but had a higher positive predictive value than did SUDS; however, there was no statistical difference between the tests. When SUDS was compared with IFA, in which a titer of greater than or equal to 1:16 was considered significant, the high negative predictive value (100%), excellent sensitivity (100%) and specificity (98.3%), and ease of performance made SUDS an attractive alternative to IHA for screening single serum specimens for toxoplasmosis.

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The slide agglutination test (SAT), microagglutination test (MAT), and card agglutination test (CAT) were compared with each other, using the tube agglutination test (TAT) as the standard method, by two reference laboratories to determine effectiveness as screening tests for human brucellosis. TAT titers of 1,253 sera tested in both laboratories were compared. In one laboratory, 1,270 sera were tested by the TAT and SAT, while the other laboratory tested 1,261 sera by both methods. Of these sera, 1,155 were tested in one laboratory by the CAT and 187 sera were tested by the MAT. Compared with that of the TAT (greater than or equal to 160 positive), the sensitivities were 97 to 100% (SAT), 90% (CAT), and 88% (MAT). The specificities were 88 to 89% (SAT), 98% (CAT), and 88% (MAT). For populations with a low prevalence of disease, increased specificity offers higher predictive value, so the CAT and MAT are preferable for screening purposes and the choice between tests depends on the number and frequency of tests performed. All sera reactive in the CAT and MAT should be retested with the TAT.

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The sensitivity and specificity of the Bio-EnzaBead test for syphilis and the fluorescent treponemal antibody-absorption (FTA-ABS) test were determined by examining 262 serum samples, including 202 serum samples from patients with confirmed syphilis in various stages. Overall correlation with patient history was 95.8% with both tests. False-negative Bio-EnzaBead tests occurred in 9 of 86 (10.5%) cases of late-latent syphilis (greater than 2 years) and in 1 of 38 (2.6%) cases for which the stage of disease could not be determined. False-negative FTA-ABS tests occurred in 5 of 86 (5.8%) cases of late-latent syphilis (greater than 2 years) and in 2 of 38 (5.3%) cases for which the stage of disease could not be determined. One false-positive test occurred with Bio-EnzaBead, and the cause could not be determined. The reproducibility of the Bio-EnzaBead test was excellent when spectrophotometric readings were calibrated against either air or substrate blanks. The Bio-EnzaBead test for syphilis is a suitable alternative to the FTA-ABS test.

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In October 1981, an outbreak of 29 cases of community-acquired pneumonia occurred among adult residents of Johnson County, Iowa. Retrospective study revealed 12 cases (41 per cent) had laboratory evidence of Legionnaires' disease (LD). No significant differences in clinical or epidemiological features were found between LD cases and the other pneumonias in the outbreak. All LD cases received erythromycin; one case died for a case-fatality rate of 8 per cent. The outbreak's focus could not be identified.

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