Mark S. Dworkin

The Changing Epidemiology of Invasive Haemophilus influenzae Disease, Especially in Persons ⩾65 Years Old

BACKGROUNDnFew studies have reported the epidemiological characteristics of Haemophilus influenzae disease among adults.nnnMETHODSnPublic health surveillance and hospital discharge data from Illinois were examined to determine the descriptive epidemiological characteristics and trends of invasive H. influenzae disease, and mortality data from Illinois were compared with data from several other states.nnnRESULTSnDuring January 1996-December 2004, 770 cases of invasive H. influenzae disease were reported to the Illinois Department of Public Health (Springfield). The incidence of disease increased from 0.4 to 1.0 cases per 100,000 persons, including an increase of incidence in adults aged > or = 65 years from 1.1 to 3.9 cases per 100,000 persons. Nontypeable H. influenzae disease accounted for the greatest proportion of cases (35.8%-61.5%) in all but 1 age group. The number of cases of invasive nontypeable H. influenzae disease increased by 657%, from a low of 7 cases in 1996 to a high of 53 cases in 2004; as a proportion of annual cases, nontypeable H. influenzae disease increased from 17.5% in 1996 to 70.7% in 2004. Overall, the case-fatality rate was 12.7%, with the highest rate observed in persons aged > or = 65 years (20.6%). The case-fatality rate was similar for the hospital discharge database and for Indiana, Maryland, Oregon, and Wisconsin (range, 12.9%-18.2%).nnnCONCLUSIONSnIn Illinois, the incidence of invasive H. influenzae disease increased from 1996 to 2004, and its epidemiological characteristics changed from a disease predominantly found in children and dominated by serotype b to a disease predominantly found in adults and dominated by nontypeable strains.

TICK-BORNE RELAPSING FEVER IN NORTH AMERICA

Relapsing fever is characterized by recurring episodes of fever and nonspecific symptoms (e.g., headache, myalgia, arthralgia, shaking chills, and abdominal complaints). The illness is caused by an infection from the Borrelia species (spirochetes) that may be acquired through the bite of an infected tick (Ornithodoros species) or contact with the hemolymph of an infected human body louse (Pediculus humanus). In North America, most cases have been acquired in the western United States, southern British Columbia, and few cases have been reported from Mexico. Most cases have been acquired from exposure to rustic tick-infested cabins and caves. This article reviews relapsing fever, especially tick-borne relapsing fever in North America.

An Outbreak of Varicella among Children Attending Preschool and Elementary School in Illinois

In our investigation of a varicella outbreak among students in preschool, kindergarten, and grades 1-3 in Winnebago County, Illinois, we found an overall varicella vaccine efficacy of 88%, evidence that the circulating virus was a wild-type strain (as determined by polymerase chain reaction analysis), and evidence that vaccination of children </=15 months of age was associated with an increased risk for breakthrough varicella (relative risk, 3.7; 95% confidence interval, 1.1-13.1; P=.04). The efficacy of varicella vaccine might be improved if administration of the initial vaccine dose is delayed until children are >/=15 months of age.

The Epidemiology of Blastomycosis in Illinois and Factors Associated with Death

BACKGROUNDnBlastomycosis is a systemic fungal disease that may be asymptomatic or progressive and may lead to death.nnnMETHODSnIn response to a reported increase in the number of cases of blastomycosis in Illinois, surveillance data reported to the Illinois Department of Public Health from January 1993 to August 2003 were analyzed and the medical records of 4 patients who died were reviewed.nnnRESULTSnAmong the 500 cases reported, the median age of the patients was 43 years (range, 4-87 years), and 34 patients (7%) died. Higher rates of mortality were observed among persons who were black, who were > or =65 years of age, and who were male. The median time from onset of illness to diagnosis was 128 days (range, 12-489 days). Death was associated with a time from onset of illness to diagnosis of > or =128 days (OR, 2.1; 95% CI, 1.0-4.8). During the period from 1993 through 2002, the number of cases reported per year increased from 24 to 87 (P<.05).nnnCONCLUSIONSnThe incidence of blastomycosis has been increasing in Illinois. To reduce mortality related to delay in diagnosis and treatment, medical providers need to be educated about blastomycosis, with an emphasis on symptom recognition, methods of diagnosis, and appropriate antifungal treatment.

Outbreak of Enterotoxigenic Escherichia coli Infection with an Unusually Long Duration of Illness

BACKGROUNDnEnterotoxigenic Escherichia coli (ETEC) is an emerging cause of foodborne outbreaks of infection in the United States, yet its epidemiology is not completely understood.nnnMETHODSnIn September 2004, we investigated an outbreak of infection due to ETEC at an Illinois corporation following a meal served to approximately 700 employees. Clinical samples were negative for enteric pathogens and were tested for ETEC using stool culture and polymerase chain reaction (PCR). An environmental investigation was conducted to determine whether food-service practices or conditions led to this outbreak. A case of illness caused by ETEC was defined as onset of diarrhea and > or =1 of the following symptoms during 23-30 September 2004: cramps, vomiting, nausea, headache, or weight loss.nnnRESULTSnThe 111 ill employees interviewed had only 1 meal in common. Cucumber salad and noodle salad from that meal were associated with illness; no food was available for testing. A PCR test for ETEC in stool was positive in samples from 6 of 11 patients; 3 ETEC serotypes were detected. The environmental investigation revealed no critical violations. The median duration of diarrhea (7 days) was longer than that observed for the majority of outbreaks of ETEC infection (4 days) and was associated with consumption of carbonated beverages (odds ratio, 4.5; 95% confidence interval, 2.0-10.3).nnnCONCLUSIONSnEmerging features of ETEC identified in this outbreak include the organisms role in domestic outbreaks and its ability to cause prolonged diarrheal illness. Additionally, integrating the results of nonculture-based diagnostic techniques into foodborne outbreak surveillance presents challenges under the current guidelines of the Centers for Disease Control and Prevention.

Adults Are Whooping, but Are Internists Listening?

Reports of pertussis in the United States have been increasing for more than 20 years (1). From 1990 to 2001, the incidence rate of pertussis in adults has increased 400% (2, 3). In Illinois, more than 1100 cases of pertussis were reported in 2004. Unfortunately, although pertussis may be responsible for approximately one fourth to one fifth of cases of cough lasting more than 2 weeks in adults and adolescents, physicians have generally considered pertussis a pediatric illness. As a Centers for Disease Control and Prevention Epidemic Intelligence Service Officer in Washington State in 1995, I received a telephone call from a frustrated nurse working at a county health department in central Washington. She appealed to me to speak to a local physician who refused to test or treat an adult with chronic cough for pertussis, despite what I now recognize to be compelling information to support suspicion of that diagnosis. The physician told her, Adults dont get pertussis. When I hung up the telephone, my first thought was, I didnt know adults can get pertussis. I must admit my initial bias was in favor of the physician. I had recent board certification from the American Boards of Internal Medicine and Infectious Diseases and a masters degree in public health. Pertussis had not come up in the differential diagnosis of any inpatient or outpatient cases I had seen during my internal medicine training in Chicago or my infectious diseases training in New Orleans. I did not recall any emphasis on pertussis in adults in my public health curriculum. Since my initial encounter with the issue of pertussis in adults, I have learned that a lack of knowledge and myths about pertussis prevent this illness from being recognized as an important cause of community-acquired respiratory tract illness that may be fatal to infants. As long ago as 1935, the Journal of Pediatrics published a paper that reviewed the preceding 15 years of literature on pertussis in adults (4). The author also summarized a 1916 report by a New York City epidemiologist who postulated that adults with unrecognized pertussis were disseminating the disease. This article cited an outbreak of pertussis among office workers that had occurred approximately 75 years earlier (5) than a 1995 outbreak I investigated among office workers in Snohomish County, Washington. In a 1968 article in Annals of Internal Medicine (6), Morse described data from Michigan demonstrating that one third of patients with pertussis were older than 20 years of age. He concluded from outbreak data presented elsewhere that pertussis immunization is not lifelongit is barely a decade long. He also wrote, It seems likely that postimmune pertussis will turn out to be a relatively common occurrence and that internists experience will provide the major basis for future decisions regarding treatment and prophylaxis (6). These words seem to have fallen on deaf ears. Since 1968, additional publications in widely read medical journals document that pertussis in adults is not a zebra diagnosis but instead deserves a place on the list of community-acquired adult pathogens. These reports of pertussis in adults include an outbreak in a Wisconsin nursing home; an outbreak in a Wisconsin facility for the developmentally disabled; a study of adults with pertussis during an outbreak in Chicago; an outbreak of pertussis in Vermont in which 23% of those affected were at least 20 years of age; an outbreak in a California hospital; an outbreak of pertussis at an Illinois oil refinery; and the death of an 82-year-old woman after a cough illness, respiratory failure, and identification of Bordetella pertussis from a blood culture (3, 7-12). Evidence also strongly supports the inclusion of pertussis in the differential diagnosis of chronic cough illness in adults and adolescents. Between 1987 and 2001, at least 6 studies published from several countries, including the United States, examined a cough illness with duration varying from 6 days or more to 1 month or more and found that pertussis was responsible for 12% to 32% of these illnesses (13-18). The prevalence of pertussis among patients with chronic cough is likely to vary by region and time, and studies may overestimate the true prevalence due to such limitations as inclusion of serologic methods for diagnosis (13-18) and possible selection of patients with more severe cough illness (18) (for example, those seeking emergency department care) (17). Despite these limitations, these studies have demonstrated that pertussis may explain a substantial minority of chronic cough illness. It has been estimated that more than 1 million cases of pertussis occur in the United States each year (19). Along with the national increase in reported cases of pertussis, adults and adolescents have represented a substantial proportion of the documented disease. For example, during a community outbreak in Rock Island County, Illinois, 68% of 151 pertussis cases identified through a combination of passive and active surveillance involved adults and adolescents, including 42% who were older than 20 years of age (20). During this and other outbreak investigations of pertussis, a frequently encountered barrier to disease control is lack of recognition and knowledge related to diagnosis, treatment, infection control, prophylaxis, and reporting, especially among physicians for adults. In one study of the prevalence of pertussis among adults at a San Francisco health maintenance organization, the authors reported that patients had visited their physicians as often as 9 times for cough symptoms (13) and that none of the 153 referrals for cough persisting for 2 weeks or longer had pertussis documented as a suspected diagnosis or differential diagnosis. A survey of 130 Washington State internists demonstrated that only 38% of respondents were aware that childhood immunization with pertussis vaccine did not provide lifelong immunity, only 36% knew that the nasopharyngeal swab was the preferred method for collection of a sample, and only 45% knew that 2 weeks of antimicrobial prophylaxis was indicated for all close contacts of case-patients (21, 22). A more recent survey of a sample of 58 internists, family practice physicians, and pediatricians in McHenry County, Illinois, found that nonpediatricians predictably knew less about pertussis than their pediatrician counterparts. However, even more concerning for me as a public health professional was that knowledge of what constituted a reportable case was equally low for both groups (41% of pediatricians and 43% of nonpediatricians, respectively) (Illinois Department of Public Health. Unpublished data). Beyond the difficulty of getting physicians to report notifiable diseases to their local health department, physicians often dont know that certain conditions meet case definitions for surveillance of these diseases. For example, the Centers for Disease Control and Preventions case definition for probable (nonoutbreak) cases of pertussis includes any person with a cough illness lasting at least 2 weeks and accompanied by paroxysms, post-tussive vomiting, or whooping (without other apparent cause) (23). Failure to report probable (and confirmed) cases of pertussis creates a barrier to the enforcement of state governments public health rules and regulations. Such rules and regulations are designed to prevent further disease transmission from person to person to infants, in whom it would probably cause hospitalization and possibly tragic preventable death. Such infant deaths increased during the 1990s (24), and adults are frequently the source of pertussis in infants (25, 26). Unfortunately, diagnosis and treatment are not as straightforward for pertussis as for many other infectious diseases. Serologic tests are relatively convenient, but most U.S. laboratories that perform them do not have a standardized method. Therefore, such tests (except for those performed at the Massachusetts State Laboratory Institute) are not considered reliable. When tests are performed by an appropriate laboratory, high IgA titers (or high IgM titers in unimmunized persons) suggest recent infection (27). A standardized single serum assay for national use is being developed but is not currently available. None of the commercial serologic tests for pertussis have been licensed in the United States for routine diagnostic use (28). Once a common technique, the direct fluorescent antibody test has fallen out of favor because of problems with false-positive results. The preferred test is the nasopharyngeal aspirate or swab for polymerase chain reaction and culture confirmation. However, barriers to the successful use of these techniques include lack of familiarity with the procedure, reluctance to make the patient uncomfortable because the swab is inserted relatively deep, and lack of knowledge about the swabs. Dacron and calcium alginate swabs are preferred for culture because cotton swabs can inhibit the growth of B. pertussis and calcium alginate swabs inhibit polymerase chain reaction; Dacron and rayon swabs are the best swabs overall (29). Additional barriers include the need to obtain special transport medium (often not available when the patient consents to testing), the cost of testing when performed at a commercial laboratory, the tendency for the organism to die before culture confirmation is achieved, and the lower yield of polymerase chain reaction and culture in the setting of partial immunity and prolonged time after onset of illness. This last issue is especially frustrating, since the chronicity of the cough often alerts physicians to this possible diagnosis at a time when diagnostic yield may be poor. A common misconception is that a negative test result for pertussis rules out the diagnosis. Testing for pertussis is not sufficiently sensitive for treatment decisions to be guided by test results alone. A 14-day course of erythromycin is the first-line ch

Two outbreaks of occupationally acquired histoplasmosis: more than workers at risk.

Objective: The objective of this study was to determine the etiology and risk factors for acute histoplasmosis in two outbreaks in Illinois among laborers at a landfill in 2001 and at a bridge reconstruction site in 2003. Design: We performed environmental investigations during both outbreaks and also performed an analytic cohort study among bridge workers. Participants: Workers at the landfill during May 2001 and those at the bridge site during August 2003 participated in the study. At the landfill, workers moved topsoil from an area that previously housed a barn; at the bridge, workers observed bat guano on bridge beams. Evaluations/Measurements: We defined a case by positive immunodiffusion serology, a ≥ 4-fold titer rise in complement fixation between acute and convalescent sera, or positive urinary Histoplasma capsulatum (HC) antigen. Relative risks (RR) for disease among bridge workers were calculated using bivariate analysis. Results: Eight of 11 landfill workers (73%) and 6 of 12 bridge workers (50%) were laboratory-confirmed histoplasmosis cases. Three bridge workers had positive urinary HC antigen. At the bridge, seeing or having contact with bats [RR = 7.0; 95% confidence interval (CI), 1.1–43.0], jack-hammering (RR = 4.0; 95% CI, 1.2–13.3), and waste disposal (RR = 4.0; 95% CI, 1.2–13.3) were the most significant job-related risk factors for acquiring histoplasmosis. Conclusions: Workers performing activities that aerosolized topsoil and dust were at increased risk for acquiring histoplasmosis. Relevance to Professional and Clinical Practice: Employees should wear personal protective equipment and use dust-suppression techniques when working in areas potentially contaminated with bird or bat droppings. Urinary HC antigen testing was important in rapidly identifying disease in the 2003 outbreak.

Investigation of Healthcare-Associated Transmission of Mycobacterium tuberculosis among Patients with Malignancies at Three Hospitals and at a Residential Facility

Immunocompromised patients have an increased risk of experiencing progression of latent Mycobacterium tuberculosis infection (LTBI) to active tuberculosis (TB) disease. In January 2002, 2 patients with leukemia (Patients 1 and 2) developed pulmonary TB after recent exposure at 3 hospitals (Hospital A, Hospital B, and Hospital C) and at a residential facility for patients with cancer. Neither was known to have LTBI. Within 1 year, 3 other patients with malignancy and TB disease had been identified at these facilities, prompting an investigation of healthcare facility–associated transmission of M. tuberculosis.

Trends in Nephropathy Among HIV-Infected Patients

BACKGROUNDnNephropathy complicates the course and adversely impacts on the prognosis of HIV-infected patients. We examined trends and correlates of all-cause nephropathy (ACN).nnnMETHODSnCorrelates of and trends in ACN were examined in the entire Adult/Adolescent Spectrum of HIV Disease longitudinal observational cohort. Patients were enrolled and followed in the cohort for a median period of 3 years between January 1990 and December 2003 in 11 US metropolitan areas.nnnRESULTSnThe incidence of ACN rose among HIV-infected individuals through the mid-1990s, then declined. The proportion of patients with ACN at the time of death increased over the study period. Black race, injection-drug use (IDU), indinavir, hypertension, diabetes, decreased CD4+ lymphocyte count, increased viral load, and increased age were all highly associated with ACN.nnnDISCUSSIONnNephropathy represents an important health disparity impacting HIV-infected blacks and IDU with implications for mortality.

Rash as a Prognostic Factor in West Nile Virus Disease

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