Adult blood lead epidemiology and surveillance--United States, 1998-2001.

PROBLEM/CONDITION: Elevated blood lead levels (BLLs) in adults can damage the cardiovascular, central nervous, reproductive, hematologic, and renal systems. The majority of cases are workplace-related. U.S. Department of Health and Human Services recommends that BLLs among all adults be reduced to < 25 microg/dL. The highest BLL acceptable by standards of the U.S. Occupational Safety and Health Administration is 40 microg/dL. The mean BLL of adults in the United States is < 3 microg/dL. REPORTING PERIOD: This report covers cases of adults (aged > or = 16 years) with BLLs > or = 25 microg/dL, as reported by 25 states during 1998-2001. DESCRIPTION OF SYSTEM: Since 1987, CDC has sponsored the state-based Adult Blood Lead Epidemiology and Surveillance (ABLES) program to track cases of elevated BLLs and provide intervention consultation and other assistance. Overall ABLES program data were last published in 1999 for the years 1994-1997. This report provides an update with data from 25 states reporting for > or = 2 years during 1998-2001. During that period, the ABLES program funded surveillance in 21 states - Alabama, Arizona, Connecticut, Iowa, Maryland, Massachusetts, Michigan, Minnesota, New Jersey, New York, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, Texas, Washington, Wisconsin, and Wyoming. Four additional states - California, Nebraska, New Hampshire, and Utah contributed data without CDC funding. RESULTS: During 1998-2001, the overall program's annual mean state prevalence rate for adults with BLLs > or = 25 microg/dL was 13.4/100,000 employed adults. This compares with 15.2/100,000 for 1994-1997. Yearly rates were 13.8 (1998), 12.9 (1999), 14.3 (2000), and 12.5 (2001). For adults with BLLs > or = 40 microg/dL, the overall program's annual mean state prevalence rare during 1998-2001 was 2.9/ 100,000 employed adults. This compares with 3.9/100,000 for 1994-1997. Yearly rates were 3.3 (1998), 2.5 (1999), 2.9 (2000), and 2.8 (2001). INTERPRETATION: Although certain limitations exist, the overall ABLES data indicate a declining trend in elevated BLLs among employed adults. PUBLIC HEALTH ACTIONS: ABLES-funded states increased from 21 to 35 in 2002, and more detailed reporting requirements were put into effect. These, and other improvements, will enable the ABLES program to work more effectively toward its 2010 target of eliminating all cases of BLLs > or = 25 microg/dL in adults caused by workplace exposures.

Epidemiology of salmonellosis in Arkansas.

Human salmonellosis continues to be a major public health issue. Our epidemiologic review of cases from 1989 to 1992 was done to define the current reported rate of infection due to Salmonella species for the state of Arkansas, which might be expected to have higher rates of infection because it is a leading producer of poultry. Results showed that the reported case rate in Arkansas (18.0/100,000) did not differ from that of the United States at large (18.6/100,000). Age-specific rates, however, showed that children less than 1 year of age in Arkansas were infected at a higher rate than those in the remainder of the nation. Salmonella newport and S typhimurium were the most commonly isolated serotypes. Individuals living in a county with poultry processing plants and hatcheries were not more likely to have salmonellosis, and individuals residing in Arkansas do not appear to be at increased risk of salmonellosis because of the poultry industry.

Epidemiologic aspects of a St. Louis encephalitis epidemic in Jefferson County Arkansas, 1991.

In 1991, the first epidemic of St. Louis encephalitis (SLE) ever reported in Arkansas resulted in 25 cases in Pine Bluff (attack rate: 44 per 100,000; 95% confidence interval [CI] 28-65). To identify risk factors for SLE viral infection and risk factors for neuroinvasive illness, we conducted a community-based, cross-sectional study of noninfected and asymptomatically infected persons and a case-control study of asymptomatically and symptomatically infected persons. The SLE viral infection rate was similar in all age groups and in all studied census tracts. Risk factors for asymptomatic infection included: living in a low income household (relative risk [RR] = 2.6, 95% CI 1.1-6.0), sitting outside in the evening (RR = 2.1, 95% CI 1.0-4.8), and living in homes with porches (RR = 2.9, 95% CI 0.9-9.3) or near open storm drains (RR = 2.2, 95% CI 1.0-4.9). Compared with asymptomatically infected persons, symptomatic persons were older (odds ratio [OR] for age > or = 55 years = 13.0, 95% CI 1.2-334) and more likely to have a previous history of hypertension (OR = 8.5, 95% CI 1.1-72). Our results indicate that advanced age is the most important risk factor for developing encephalitis after infection with SLE virus. Hypertension and vascular disease may predispose to neuroinvasive disease, but this epidemiologic study has not ruled out the confounding effects of age.

St. Louis encephalitis in Arkansas.

The first outbreak of St. Louis encephalitis (SLE) in Arkansas occurred in Pine Bluff (Jefferson County) during July-August 1991. Cases of SLE were identified mainly through reporting by physicians in Jefferson and surrounding counties. In addition, testing of stored cerebrospinal fluid specimens, a hospital chart review, and a serosurvey were performed in Pine Bluff. Twenty-eight Arkansas residents, five of whom died, had cases of SLE. Half the case patients were over age 60, and nearly half had hypertension. The serosurvey confirmed that infection with the SLE virus was not new to Pine Bluff, and that most infections in 1991 were asymptomatic. Arkansas physicians may see more cases of SLE in 1992. SLE epidemiology, clinical presentation, diagnosis, and preventive measures are reviewed.

Racial differences in susceptibility to infection by Mycobacterium tuberculosis.

The prevalence of tuberculosis among blacks is known to be about twice that among whites. When we looked at infection rates among the initially tuberculin-negative residents of 165 racially integrated nursing homes in Arkansas, we were stimulated to investigate whether this difference could be due in part to racial differences in susceptibility to Mycobacterium tuberculosis infection. A new infection was defined by an increase of greater than or equal to 12 mm of induration after a tuberculin skin test (5 tuberculin units) administered at least 60 days after a negative two-step test. On repeat skin testing of the 25,398 initially tuberculin-negative nursing home residents, we found that 13.8 percent of the blacks and only 7.2 percent of the whites had evidence of a new infection (relative risk, 1.9; 95 percent confidence interval, 1.7 to 2.1). Blacks were infected more frequently, regardless of the race of the source patient. In homes with a single source patient who was white, 17.4 percent of the black and 11.7 percent of the white residents became infected (relative risk, 1.5; 95 percent confidence interval, 1.2 to 1.9); in homes with a single source patient who was black, 12.4 percent of the black and 7.7 percent of the white residents became infected (relative risk, 1.6; 95 percent confidence interval, 1.2 to 2.1). However, there was no racial difference in the percentage of residents who had recently converted to positive status who, in the absence of preventive therapy, were later found to have clinical tuberculosis (blacks, 11.5 percent; whites, 10.6 percent). Data from three outbreaks of tuberculosis in two prisons also showed that blacks have about twice the relative risk of whites of becoming infected with M. tuberculosis. We conclude that blacks are more readily infected by M. tuberculosis than are whites. The data also suggest that susceptibility to M. tuberculosis infection varies independently of the factors governing the progression to clinical disease.

Epidemic of restaurant-associated illness due to Salmonella newport.

In June and July 1982, a large outbreak of gastroenteritis associated with a barbecue restaurant involved 120 persons in central Arkansas. The illness was characterized by diarrhea, abdominal pain, and vomiting; 23 patients (19%) were hospitalized. Epidemiologic investigation showed that persons who became ill were more likely to have eaten ham or pork sandwiches at the restaurant before their illness than those who remained well. Stool cultures from 19 customers and each of the eight restaurant employees were positive for Salmonella newport. Cultures of a ham slice obtained from the restaurant and a partially consumed pork sandwich obtained from one ill person both grew Salmonella of same serotype.

Tuberculosis as an endemic and nosocomial infection among the elderly in nursing homes.

We studied reactivity to tuberculin skin testing in nearly all nursing home residents in Arkansas. Only 12 per cent of the 12,196 newly admitted residents were tuberculin positive, as compared with 20.8 per cent of the 13,441 residents who were first tested more than a month (mean, 30 months) after admission. The proportion of persons who were positive on initial testing varied greatly with the time spent in the home before testing. Those who were not reactive on initial testing had a 5 per cent rate of conversion for each year spent in a home with a known recent infectious case (within three years) and a 3.5 per cent rate for each year in a home with no recognized recent case. Active tuberculosis developed in only 1 of 534 persons with positive tuberculin tests or previous reactions who were treated with isoniazid, but in 79 (2.4 per cent) of 3270 persons who were not (P less than 0.001). The disease developed in only 1 (0.16 per cent) of 605 persons whose tests converted to positive and who were treated with isoniazid, as compared with 45 (5.9 per cent) of 757 whose tests converted but who were not treated (P less than 0.001). We conclude that new infection with tuberculosis is an important risk for nursing home patients and that greater care should be taken to detect and treat new infections before the disease develops and the infection spreads.

Epidemic tuberculosis in a nursing home: a retrospective cohort study.

In a retrospective study, the results of tuberculin skin tests done in a nursing home were examined, where most residents admitted during 1972-1981 were tested using purified protein derivative of tuberculin administered intradermally. Of 514 residents who were tested at least once during the study period, results of the admission skin test were available for 254 and follow-up skin test results were available for 226. On admission, 13 per cent (35/254) were skin-test positive (greater than or equal to 10 mm induration at 48 hours). Skin test positivity for males was 16 per cent, females, 11 per cent, nonwhites, 19 per cent, and whites, 12 per cent. Highest skin test positivity was for persons received as transfers from other nursing homes (24 per cent) and lowest was for those entering from individual homes (8 per cent, P = 0.016, Fisher's Exact Test). On follow-up, 38/226 (17 per cent) residents who had been tuberculin-negative on at least two previous occasions were found to be positive; 24 (63 per cent) of these conversions occurred in a single year (1975) following detection of an infectious patient. The infection rate for persons residing in the nursing home during that year was 28 per cent (28/99) compared with 7.9 per cent (10/127) for persons either discharged before or admitted after 1975 (relative risk = 3.6, P less than 0.001). Ten to 15 per cent of new residents are tuberculin-positive (harbour a dormant tuberculous infection), leaving 85-90 per cent of newly admitted persons who are tuberculin-negative and thus susceptible to infection if exposed. The study shows that tuberculosis must be considered as a potential nosocomial infection in nursing homes.(ABSTRACT TRUNCATED AT 250 WORDS)

Imported measles outbreak in a university.

In 1981, a measles outbreak in an Arkansas university involved 16 students and four persons who were contacts of these students. The first two cases were in students who recently returned from Honduras. Of the 16 students with measles, 12 had significant gastrointestinal symptoms; five had elevated liver transaminase, and eight were hospitalized. Only two of the students were considered adequately immunized. A voluntary immunization clinic held on the university campus resulted in 67 per cent of 3,076 students being vaccinated.

A multistate outbreak of infections caused by Yersinia enterocolitica transmitted by pasteurized milk.

In June and July 1982, a large interstate outbreak of Yersinia enterocolitica infections caused by an unusual serotype occurred in Tennessee, Arkansas, and Mississippi. Eighty-six percent of cases had enteritis characterized by fever, abdominal pain, and diarrhea. In three separate case-control studies, drinking milk pasteurized by plant A was statistically associated with illness. In a survey of randomly chosen households, 8.3% of persons who recalled having drunk milk from plant A during the suspect period experienced a yersiniosislike illness. Inspection of the plant and cultures of the available raw and pasteurized milk did not reveal the source or mechanism of contamination or a breach in normal pasteurizing technique. Although outbreaks of enteric disease caused by pasteurized milk are rare in the United States, the ability of Y enterocolitica to grow in milk at refrigeration temperatures makes pasteurized milk a possible vehicle for virulent Y enterocolitica. The extent to which milk is responsible for sporadic cases of yersiniosis is unknown.

Aseptic meningitis and high school football players. 1978 and 1980.

During 1978 and 1980, epidemiologists at the Centers for Disease Control investigated seven outbreaks of aseptic meningitis-like illness (AMLI) occurring in high school football players in four different states. One or more enterovirus types were isolated from affected students at all seven schools. Attack rates were highest among the varsity football teams (range, 21% to 68%), although junior varsity teams were also affected at most schools (range, 5% to 63%). Non-football athletes were relatively spared. The illness was also reported by nonathletes at all three schools where more extensive investigations were undertaken. At one school, the AMLI attack rate was higher among students who were close friends of football players than among students who were not close friends; at the other two schools, these rates were similar. Hospitalization was more likely for football players with AMLI than for affected nonfootball players. Transmission of enteroviruses among football players was probably from person to person, although there was additional evidence to implicate common vehicle transmission at two schools. We conclude that football players may or may not have been more likely to be exposed to the enteroviruses circulating in their communities, but once introduction of a virus into a team occurred, transmission potential may have been enhanced, resulting in a large number of AMLI cases in players.

Fatal salmonellosis originating in a clinical microbiology laboratory.

Laboratory-acquired infections concern all microbiologists. During ongoing surveillance of laboratory-acquired enteric infections, salmonella infections in the wife and son of a laboratory worker were documented; the first case was fatal. Neither patient had had any contact with the laboratory. The infecting organisms were Salmonella typhi and a multiply resistant strain of Salmonella agona that were being worked within the laboratory; both strains had been received 1 to 2 years previously for proficiency testing exercises. This report documents the transmission of enteric pathogens beyond the confines of the laboratory, with its tragic outcome, and suggests measures to prevent the recurrence of this problem.

Eradication of epidemic methicillin-gentamicin-resistant staphylococcus aureus in an intensive care nursery.

A methicillin-resistant strain of Staphylococcus aureus (phage type 47,54,75,83A) became epidemic in our 50 bed level III nursery, with a colonization rate of 70 percent and an infection rate of more than 25 percent. This prevalence and the appearance of gentamicin resistance necessitated epidemic control measures. Standard measures included separate housing for infants in whom colonization had occurred and infants in whom it had not, low nurse to patient ratios, and cohorting of all personnel. Use of all antibiotics was curtailed by the requirement of infectious disease consultation. Gentamicin was available only on order of the Director. The colonization rate fell from 55 percent to 25.4 percent, the first-week colonization rate from 31 percent to 0 percent, and the infection rate from 29.3 percent to 15.9 percent over eight weeks. The mean duration of antibiotic therapy decreased from 12.21 to 9.05 days per treated patient; however, the frequency of gentamicin usage and the proportion of gentamicin resistance were unchanged. Nurse to patient ratios were modified to allow increased admissions, but cohorting was continued for 12 weeks until all infants in whom colonization had occurred were discharged. With the elimination of the reservoir, no further colonization occurred and antibiotic resistance did not reappear. Standard infection control measures can eliminate epidemics of multiple antibiotic-resistant Staph. aureus, and control of antibiotic usage may present re-emergence of resistant strains.