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Biomedical subjects

W N Hall

Publications and source records attributed to W N Hall.

At least 19 recordsLinked to original sources
PubMed1997

An international outbreak of Salmonella infections caused by alfalfa sprouts grown from contaminated seeds.

An outbreak of Salmonella serotype stanley infections occurred in the United States and Finland in 1995. The outbreak was investigated through case-control studies in Arizona, Michigan, and Finland; by isolate subtyping; and by tracing and culturing of the implicated food. Alfalfa sprout consumption was the only exposure associated with S. stanley infections in Arizona (matched odds ratio [MOR] = 11.1; 95% confidence interval [CI], 1.4-513), Michigan (MOR = 5.5; CI, 1.6-23), and Finland (MOR undefined; CI, 4.9-infinity). US and Finnish patient isolates were a unique outbreak strain distinct from S. stanley isolates not linked to the outbreak. Alfalfa sprouts eaten by patients in 6 US states and Finland were traced to seed shipped by a Dutch shipper. Thus, it was concluded that alfalfa sprouts grown from contaminated seed caused an international outbreak of > or =242 S. stanley infections in > or =17 US states and Finland. This outbreak illustrates a new mechanism through which contamination of fresh produce can cause large, widely dispersed outbreaks.

Adolescent↗
PubMed1996

Outbreak of histoplasmosis among employees in a paper factory--Michigan, 1993.

In December 1993, four reported cases of histoplasmosis among employees in a Michigan pulp paper factory prompted an investigation. A cohort of employees was surveyed to identify additional cases. A case of acute histoplasmosis was defined as an influenza-like illness in a plant employee with the onset of illness during October or November 1993 and laboratory evidence of recent infection with Histoplasma capsulatum. Among the 96 employees surveyed, 18 persons met the case definition; all of these had illness onset during the last week of October in 1993. The attack rate among maintenance employees (16 of 53 [30%]) was much greater than that among nonmaintenance employees (2 of 43 [5%]) (relative risk = 6.5; 95% confidence interval = 1.6 to 26.7; P = 0.003). On October 22, a dry, windy day, one maintenance worker swept bird guano, approximately 10 cm deep, from an adjacent roof < 20 m from the maintenance building. The disturbance of the bird guano was the likely event which caused this outbreak. H. capsulatum remains an important pathogen among immunocompetent hosts. We recommended that the plant authorities (i) discourage birds from roosting at the facility and (ii) use safe procedures for the cleanup and disposal of soil contaminated with bird droppings.

Adult↗
PubMed1994

Isolation of Borrelia burgdorferi from two patients in Michigan.

Borrelia burgdorferi was isolated from skin biopsy specimens of erythema chronicum migrans lesions on two individuals residing in Menominee County, Michigan, in 1992. To our knowledge, these are the first two cases of culture-confirmed Lyme disease in Michigan. In spite of prompt treatment and resolution of illness, antibodies to B. burgdorferi were detectable for at least 3 months in both patients. Both specimens were obtained at different rural medical practices, thus demonstrating that with adequate laboratory support it is feasible to confirm a diagnosis of acute Lyme disease by culture in rural health care settings.

Adult↗
PubMed1994

Bronchoscopy-associated Mycobacterium xenopi pseudoinfections.

Mycobacterium xenopi typically accounts for less than 0.3% of all clinical mycobacterial isolates. Over a 37-mo period, 21 (35%) of 60 mycobacterial isolates from a Michigan hospital were identified as M. xenopi. Hospital, laboratory, and bronchoscopy records were reviewed to determine case characteristics, develop a case series, and calculate procedure-specific M. xenopi isolation rates. A case-control study was conducted to elucidate aspects of the bronchoscopy procedure associated with M. xenopi isolation. Bronchoscope cleaning procedures were reviewed, and hospital water systems were cultured. Four isolates were from three patients with disease attributable to M. xenopi. Of the other isolates, specimens obtained by bronchoscopy were more likely to yield M. xenopi than were specimens obtained by other routes (relative risk, 9.7; 95% confidence intervals, 3.2, 29.6). Bronchoscopes were disinfected in a 0.13% glutaraldehyde-phenate and tap-water bath and then were rinsed in tap water. Water from the hot water tank supplying this area yielded M. xenopi. Mycobacteria were cultured from bronchoscopes after disinfection. M. xenopi in the tap water appears to have contaminated the bronchoscopes during cleaning. Adequate disinfection of contaminated bronchoscopes and careful collection of specimens to avoid contamination with contaminated water are essential, both for limiting diagnostic confusion caused by mycobacterial pseudoinfections and for reducing risks of disease transmission.

Adult↗
PubMed1993

Epidemic keratoconjunctivitis in a chronic care facility: risk factors and measures for control.

OBJECTIVE: To study patterns of transmission of epidemic keratoconjunctivitis (EKC) in a chronic care facility and to assess control measures and prevent future outbreaks in this setting. DESIGN: A retrospective cohort study. SETTING: A 120-bed, four-unit, skilled nursing facility. PATIENTS: Residents and employees of the above facility. INTERVENTIONS: Increased frequency of cleaning; use of bleach disinfectant; universal precautions in handling eye secretions from residents with conjunctivitis; cohorting residents by unit; suspension of new admissions; closure of common gathering areas. MEASUREMENTS: Resident demographics; possible risk factors for infection among residents (including mobility, underlying illness, medications, involvement in social activity, level of confusion) and among employees (including co-morbid illnesses and eye conditions, exposures to persons with conjunctivitis, visits to eye care specialists, use of contact lenses or glasses); testing of conjunctival specimens from symptomatic persons for viral and bacterial agents. RESULTS: Of 95 residents on three chronic care units, 47 (attack rate 49%) had onset of eye symptoms consistent with EKC between September 14 and December 7, 1990. Thirty-eight (81%) of these had onset following the onset of symptoms in a resident with dementia who, despite habitual eye-rubbing and wandering into other residents' rooms, was not isolated or restricted in any way. Attack rates were higher (though not statistically significant) among more mobile residents (60% for ambulatory residents) and among those considered by staff to be confused (56%). Rapid antigen detection and culture confirmed adenovirus type 37 as the etiologic agent. CONCLUSIONS: Transmission of infection with adenovirus type 37 was successfully interrupted following strict infection control, suspension of new admissions, cohorting of residents by unit, and change to a disinfectant that inactivates adenovirus. Recognition of conjunctivitis as an appropriate reason for restricting movement of an infected resident may have prevented extensive viral transmission in this outbreak.

Activities of Daily Living↗
PubMed1993

HIV testing in patients with tuberculosis. Physician response to national recommendations.

The epidemic of human immunodeficiency virus (HIV) disease has contributed to the resurgence of tuberculosis in the United States. For clinical and public health reasons, the Advisory Council for the Elimination of Tuberculosis has recommended that all patients with tuberculosis be tested for HIV antibodies. We reviewed the medical records of all patients with tuberculosis in whom a diagnosis was made at a Detroit medical center from July 1, 1986 to June 30, 1990, before and after recommendations were issued. Of 195 patients, 69 (35.4%) were tested for HIV antibodies: 73.7% of 57 patients whose medical records documented risk behaviors for HIV infection, and 19.6% of 138 patients who denied high-risk behaviors or whose medical records contained no risk information (relative risk of testing among patients with documented risk factors compared with others, 3.8; 95% confidence interval, 2.6 to 5.5). Testing of patients who denied risk behaviors or had no information in their records increased from 14.9% in the first 12 months to 30.4% in the last (p = 0.08, test for trend). In this population, national recommendations appear to have stimulated HIV testing, although most patients still are not being tested.

AIDS Serodiagnosis↗
PubMed1992

Delayed detection of an increase in resistant Acinetobacter at a Detroit hospital.

OBJECTIVE: To study an increase of antimicrobial-resistant Acinetobacter baumannii and to assess reasons for the delayed detection of this increase. DESIGN: Review of medical, laboratory, and infection control records. Plasmid profile analysis of available A baumannii isolates. SETTING: A 340-bed trauma and intensive care hospital in Detroit, Michigan. RESULTS: The number of hospitalized patients with resistant A baumannii increased during late 1989 and early 1990: 4 in September, 10 in October, 12 in November, 18 in December, and 23 in January (chi square for trend = 14.6, p = .0001). Forty-four (66%) of the 67 patients culture-positive for resistant A baumannii had respiratory tract colonization or infection. Of 11 resistant isolates, 6 had a similar plasmid profile and 5 had no plasmids. Under the hospital's targeted surveillance system, only positive cultures from blood or wounds were investigated; this largely respiratory increase of resistant A baumannii went unrecognized until January 1990. CONCLUSIONS: Antimicrobial resistance in A baumannii is an important concern. Such resistance is not necessarily plasmid mediated. Targeted surveillance for this and other agents of nosocomial infection should be used with caution, particularly in hospitals with many debilitated patients.

Acinetobacter↗
PubMed1988

Q fever. A call to heighten our index of suspicion.

The prevalence of Q fever infection is probably underestimated. In Michigan, the first two reported human cases of Q fever occurred in 1984. The case-patients lived in adjacent, rural counties and had multiple exposures to goats. We conducted a serosurvey of goat owners and a reference population to compare the prevalence of Q fever antibodies in the two-county area. Goat owners were almost three times more likely to be seropositive with Q fever antibodies than the reference population (43% vs 15%). Among goat owners, individual and household seropositivity prevalences were positively correlated with the number of goats, the number of positive goats, and the number of goat births on the farm. Q fever should be considered more often in the differential diagnosis of patients with compatible illness, especially those with frequent animal contact.

Adolescent↗
PubMed1988

Hepatitis B vaccination programs for hospital workers: results of a statewide survey.

To assess the implementation of hepatitis B virus (HBV) vaccination programs for hospital workers, we mailed questionnaires to all 229 licensed Michigan hospitals. The response rate was 96% (221/229); of these, 68% (150/221) had vaccination programs. Although multiple hospital characteristics were associated with the presence of a vaccination program, characteristics that independently predicted the presence of a program were medical school affiliation, nonpsychiatric specialty, and the existence of a hepatitis B immune globulin protocol. The most common reason given (56%, 40/71) for the absence of a program was insufficient worker risk of hepatitis B infection; this response was frequent in psychiatric (91%, 10/11) and rural hospitals (61%, 11/18). Among high-risk workers, attending physicians were less likely than other high-risk workers to be included in vaccination programs (68% vs. 95%, respectively). Fear of vaccine-associated acquired immunodeficiency syndrome was most frequently cited as the primary reason for vaccine refusal. We conclude that unwarranted fears about the vaccine's safety need to be dispelled, that high-risk physicians should be included in vaccination programs, and that rural and psychiatric hospital policies reflect their perceived risk of occupational HBV infection.

Cross Infection↗
PubMed1988

Adjusting morbidity ratios in two communities using risk factor prevalence in cases.

Available data on cancer incidence for 1969-1971 showed statistically elevated rates for breast cancer in St. Louis Park, Minnesota, a community with creosote contamination of the water supply, when compared with the rest of the Minneapolis-St. Paul area taken as the reference population. In order to assess the effect of other known risk factors for breast cancer, 75 persons with breast cancer in each of the two populations were interviewed to obtain frequencies of known risk factors. An adjusted morbidity ratio in the two populations and an expected case rate in the exposed community were calculated from these frequencies, using relative risk values from the medical literature. The adjusted morbidity ratio was less than 1.0, and the observed rate was almost identical to the new expectation, although the age-adjusted rates alone had suggested a significant difference in incidence. This method makes use of relative risks from published studies rather than those associated with local cases and controls. It allows more refined evaluation of differences in cancer rates between communities than can be provided by age- and sex-specific calculations alone, and may allow use of available statistics in situations where cost, temporal considerations, or population size do not favor large new studies.

Adult↗
PubMed1986

Risk factors for outbreaks of influenza in nursing homes. A case-control study.

To determine risk factors for outbreaks of influenza virus infections in chronic-care facilities for the elderly, the authors compared the characteristics of two groups of nursing homes in Genesee County, Michigan, in 1982-1983, following a community-wide epidemic caused by A/Bangkok/1/79-like (H3N2) viruses: seven homes in which an outbreak occurred (case homes) and six homes with sporadic illnesses only (control homes). The two groups were similar in many respects, including the physical characteristics of the facilities, visitation and staffing patterns, infection control practices, and demographic and clinical profiles of residents. Case homes, however, had larger resident populations than control homes (median 160 vs. 92, respectively; p = 0.028) and a lower proportion of residents who had been vaccinated with A/Bangkok antigen the previous autumn (median 51% vs. 81%, respectively; p = 0.047). Based on a retrospectively determined estimate of the efficacy of influenza vaccine in preventing illness (43%), the number of residents presumed to be susceptible to the epidemic strain was higher in case homes than in control homes (median 102 vs. 61, respectively; p = 0.0047) and was the most important factor selected by a stepwise, multivariate logistic regression model (p less than 0.0005). These findings are consistent with mathematical models of vaccine-induced herd immunity in closed populations and suggest that high rates of vaccination can reduce the risk of influenza outbreaks in this setting.

Disease Outbreaks↗
PubMed1986

Decreasing trends in Reye syndrome and aspirin use in Michigan, 1979 to 1984.

The incidence of Reye syndrome has been decreasing in Michigan, perhaps as a result of decreased aspirin use among children. To evaluate possible changes in the frequency of aspirin use, 199 families in Tecumseh, MI, with children younger than 18 years of age were interviewed by telephone in February 1981 and again in February 1983. Based on the reported use of medications for colds or influenza between 1981 and 1983, fewer parents gave aspirin (56% v 25%), but acetaminophen use did not change (59% v 55%). Younger parents and parents who had heard of the association between aspirin and Reye syndrome were more likely to stop giving aspirin. More parents chose to use either no medication or medications containing neither aspirin nor acetaminophen (6% v 32%) for the treatment of colds or influenza. Approximately 90% of parents who chose not to give aspirin for fever also gave medications for colds or influenza that did not contain aspirin. These results suggest that fewer children are receiving aspirin during illnesses that may precede Reye syndrome. The associated decrease in the incidence of Reye syndrome tends to support the hypothesis that the use of aspirin increases the risk for the development of Reye syndrome.

Acetaminophen↗
PubMed1985

Airborne transmission of measles in a physician's office.

An unusual outbreak of measles occurred in 1982 in a pediatrician's office in Muskegon, Mich. Three children, who had arrived at the office 60 to 75 minutes after a child with measles had departed, developed measles. Using a model based on airborne transmission, it is estimated that the index patient was producing 144 units of infection (quanta) per minute while in the office. Characteristics such as coughing, increased warm air recirculation, and low relative humidity may have increased the likelihood of transmission. Adequate immunization of all patients and staff, respiratory isolation and prompt care of all suspected cases, and adequate fresh-air ventilation should decrease the risk of airborne transmission of measles in this setting. Airborne transmission may occur more often than previously suspected, a possibility that should be considered when evaluating current measles control strategies.

Adolescent↗
PubMed1985

Efficacy of influenza vaccine in nursing homes. Reduction in illness and complications during an influenza A (H3N2) epidemic.

From December 10, 1982, to March 4, 1983, when influenza A (H3N2) viruses circulated in Michigan, outbreaks of influenza-like illness were identified in seven nursing homes in Genesee County; 272 (27%) of 1,018 residents were affected. Unvaccinated residents were more likely than vaccinated residents to become ill (risk ratio [RR], 2.6; 95% confidence interval [Cl], 1.8-3.6) and were subsequently more likely to be hospitalized (RR, 2.4; 95% Cl, 1.2-4.8), develop roentgenographically proven pneumonia (RR, 2.9; 95% Cl, 1.6-5.3), or die (RR, 5.6; 95% Cl, 1.2-9.1). Similar observations were made during investigations in six of the eight remaining nursing homes in Genesee County, in which 57 (12%) of 458 residents became ill sporadically. These findings suggest that influenza vaccine can reduce the incidence and severity of influenza virus infections among the elderly and chronically ill and underscore the importance of vaccination programs for those in nursing homes and in the general community.

Disease Outbreaks↗