Evaluation of Gram-positive rod surveillance for early anthrax detection.

Since 2003, Connecticut laboratories have reported Gram-positive rod (GPR) isolates detected within 32 h of inoculation from blood or cerebrospinal fluid. The objectives were to rapidly identify inhalational anthrax and unusual Clostridium spp. infections, and to establish round-the-clock laboratory reporting of potential indicators of bioterrorism. From 2003 to 2006, Connecticut's GPR surveillance system identified 1134 isolates, including 657 Bacillus spp. (none B. anthracis) and 241 Clostridium spp. Reporting completeness and timeliness improved to 93% and 92%, respectively. Baseline rates of Bacillus spp., Clostridium spp. and other GPR findings have been established and are stable. Thus far, no cases of anthrax and no unusual clusters of Clostridium spp. have been detected by the GPR surveillance system. This system would probably have confirmed the inhalational anthrax case in Pennsylvania in 2006 3 days sooner than traditional reporting. Using audits and ongoing evaluation, the system has evolved into a highly functional 24/7 laboratory telephone reporting system with almost complete reporting.

Nationwide outbreak of listeriosis due to contaminated meat.

We used molecular subtyping to investigate an outbreak of listeriosis involving residents of 24 US states. We defined a case as infection with Listeria monocytogenes serotype 4b yielding one of several closely related patterns when subtyped by pulsed-field gel electrophoresis. Patients infected with strains yielding different patterns were used as controls. A total of 108 cases were identified with 14 associated deaths and four miscarriages or stillbirths. A case-control study implicated meat frankfurters as the likely source of infection (OR 17.3, 95% CI 2.4-160). The outbreak ended abruptly following a manufacturer-issued recall, and the outbreak strain was later detected in low levels in the recalled product. A second strain was recovered at higher levels but was not associated with human illness. Our findings suggest that L. monocytogenes strains vary widely in virulence and confirm that large outbreaks can occur even when only low levels of contamination are detected in sampled food. Standardized molecular subtyping and coordinated, multi-jurisdiction investigations can greatly facilitate detection and control of listeriosis outbreaks.

Outbreak of campylobacteriosis at a senior center.

OBJECTIVES: In August 1997, campylobacteriosis was diagnosed in four older persons in one Connecticut town. We investigated this outbreak to determine its cause and to identify appropriate preventive measures. We also analyzed surveillance data to assess the impact of campylobacteriosis among persons age 65 years and older in Connecticut. DESIGN: The outbreak was investigated through a case-control study and an environmental investigation. Surveillance data were from population-based, active foodborne disease surveillance. SETTING: The outbreak and environmental studies were conducted at a senior center identified as the one eating place common to all four patients. Active surveillance data were from three Connecticut counties during 1996/1997. PARTICIPANTS: We administered a questionnaire to senior center attendees. A case was defined as onset of diarrhea with fever or abdominal cramps during August 20-25 in a person who ate at the senior center during August 18-20. Respondents without illness meeting the case definition who ate at the senior center during August 18-20 were controls. MEASUREMENTS: Case-control study participants were asked about symptoms of gastrointestinal illness and meals and foods eaten at the center. The environmental investigation gathered information about food preparation procedures and facilities. Active surveillance data were analyzed to determine age-specific annual campylobacteriosis incidence rates and proportions of cases involving hospitalization. RESULTS: For the case-control study, there were 66 respondents (16 case patients, 50 controls), representing approximately 52% of August 18-20 attendees. Case patients were more likely than controls to have eaten at a Hawaiian luau at the center. The most strongly implicated food was sweet potatoes. Review of food preparation procedures identified multiple opportunities for cross-contamination from raw meats to other foods. In Connecticut's active surveillance area during 1996/1997, the annual campylobacteriosis incidence rate was highest among young adults, but the proportion of hospitalized cases was highest among persons age 70 years and older. CONCLUSION: Campylobacter transmission occurred at the luau, likely because of cross-contamination in the kitchen. This investigation emphasizes the importance of strict separation of raw meats from other foods during preparation. Careful attention to these measures is particularly important when an older population is served.

An outbreak of Escherichia coli O157:H7 infections and haemolytic uraemic syndrome associated with consumption of unpasteurized apple cider.

During October 1996, an outbreak of Escherichia coli O157:H7 infections among Connecticut residents occurred. An epidemiologic investigation included enhanced surveillance and a case-control study. Clinical isolates of Escherichia coli O157:H7 were typed by pulsed-field gel electrophoresis (PFGE). Implicated cider samples were analysed by culture and polymerase chain reaction (PCR). Consumption of implicated cider was associated with illness; (matched odds ratio = undefined, 95 % confidence interval = 3.5-infinity). Ultimately, a total of 14 outbreak-associated patients were identified. All isolates analysed by PFGE yielded the outbreak-associated subtype. Escherichia coli O157:H7 was not cultured from three cider samples; PCR analysis detected DNA fragments consistent with Escherichia coli O157:H7 in one. This outbreak was associated with drinking one brand of unpasteurized apple cider. PFGE subtyping supported the epidemiologic association. PCR analysis detected microbial contaminants in the absence of live organisms. Washing and brushing apples did not prevent cider contamination.

A multistate outbreak of Escherichia coli O157:H7 infections associated with consumption of mesclun lettuce.

BACKGROUND: An outbreak of Escherichia coli O157:H7 infections in Connecticut and Illinois during May 28 to June 27, 1996, was investigated to determine the source of infections. METHODS: Independent case-control studies were performed in both states. Pulsed-field gel electrophoresis (PFGE) was performed on E. coli O157:H7 isolates. A case-patient was defined as a Connecticut or northern Illinois resident with diarrhea whose stool culture yielded E. coli O157:H7 of the outbreak-associated PFGE subtype. Controls were town-, age-, and sex-matched to case-patients. We traced implicated lettuce to the farm level and performed environmental investigations to identify unsafe lettuce production practices. RESULTS: In Connecticut and Illinois, infection was associated with consumption of mesclun lettuce (Connecticut matched odds ratio [MOR], undefined; 95% confidence interval [CI], 3.4 to infinity; and Illinois MOR, undefined; 95% CI, 1.4 to infinity). We traced implicated lettuce to a single grower-processor. Cattle, a known E. coli O157:H7 reservoir, were found near the lettuce fields. Escherichia coli (an indicator of fecal contamination) was cultured from wash water and finished lettuce. A trace-forward investigation identified 3 additional states that received implicated lettuce; E. coli O157:H7 isolates from patients in 1 of these states matched the outbreak-associated PFGE subtype. CONCLUSIONS: This multistate outbreak of E. coli O157:H7 infections was associated with consumption of mesclun lettuce from a single producer. Molecular subtyping facilitated the epidemiological investigation. This investigation increased the knowledge about current production practices that may contribute to the contamination of lettuce by microbial pathogens. Lettuce production practices should be monitored for microbiological safety.

Public awareness of rabies and compliance with pet vaccination laws in Connecticut, 1993.

OBJECTIVE: To determine the degree of public awareness of rabies and compliance with cat and dog vaccination laws in Connecticut in 1993. DESIGN: Monthly telephone surveys. SAMPLE POPULATION: 1,810 households. PROCEDURE: A telephone interview was conducted, using rables-related questions contained in the Behavioral Risk Factor Surveillance System, with an adult member from households randomly selected statewide by telephone number. Results of the surveys for the year were aggregated, and weighted data were analyzed. RESULTS: Ninety percent of respondents had heard about rabies during the preceding year, and 84% considered it a problem in Connecticut. Forty-seven percent of households surveyed owned dogs or cats. Ninety-three percent of dogs and 80% of cats were reported to be vaccinated against rabies. Twenty-two percent of households with cats had at least 1 cat that was not current on rabies vaccination. CLINICAL RELEVANCE: In Connecticut, an epizootic of rabies in raccoons was accompanied by a high degree of awareness of rabies and rate of reported vaccination of dogs and cats. However, vaccination of cats was less common than that of dogs. Public education efforts should emphasize the necessity to vaccinate cats and to avoid contact with unknown cats in rabies epizootic or enzootic areas. A surveillance system can be used to help evaluate public health programs.

Temporal correlations between tick abundance and prevalence of ticks infected with Borrelia burgdorferi and increasing incidence of Lyme disease.

The abundance of host-seeking Ixodes scapularis nymphs, the principal vector for the Lyme disease agent, Borrelia burgdorferi, in Old Lyme, Lyme, and East Haddam, Connecticut, was compared with the incidence of reported human Lyme disease in the 12-town area around the Connecticut River and the State of Connecticut for the period 1989 to 1996. Ticks were sampled from lawns and woodlands by dragging flannel over the vegetation and examined for the presence of B. burgdorferi by indirect fluorescent antibody staining. The infection rate of the nymphal ticks by B. burgdorferi during the 9-year period was 14.3% (of 3,866), ranging from 8.6% (1993) to 24.4% (1996). The incidence of Lyme disease was positively correlated with tick abundance in the 12 town area (r = 0.828) and the State of Connecticut (r = 0.741). An entomological risk index based upon the number of I. scapularis ticks infected by B. burgdorferi was highest in 1992, 1994, and 1996 and was highly correlated with the incidence of Lyme disease in Connecticut (r = 0.944). The number of Lyme disease cases has been influenced, in part, by annual changes in population densities of I. scapularis and, presumably, a corresponding change in the risk of contact with infected ticks. Based upon tick activity and spirochetal infection rates, epidemiologically based Lyme disease case reports on a regional scale appear to reflect real trends in disease.

A genetic-based evaluation of the principal tissue reservoir for group A streptococci isolated from normally sterile sites.

The primary sites of infection and principal reservoirs for transmission of group A streptococci are the nasopharyngeal mucosa and the impetigo lesion. However, pharyngitis and impetigo are rarely observed prior to invasive disease, and, thus, the origin of invasive strains is largely unknown. As part of an active surveillance program, group A streptococci were obtained from normally sterile tissue sites of Connecticut residents during a 6-month period. Organisms were analyzed for genetic markers that distinguish between strains that use the nasopharynx versus an impetiginous lesion as their primary site for infection. The nasopharyngeal marker was observed for most sterile-site isolates, suggesting that the upper respiratory tract is the principal reservoir from which organisms causing invasive disease are disseminated. Genotypic analyses of sterile-site isolates support the view that additional factors, aside from a recent emergence of a few virulent clones, are important contributors to invasive group A streptococcal disease.

What do physicians know about cryptosporidiosis? A survey of Connecticut physicians.

BACKGROUND: Cryptosporidiosis, an intestinal parasitic infection, has gained considerable media attention since a 1993 waterborne outbreak in Milwaukee, Wis, in which more than 400,000 persons became ill. However, the incidence of and risk factors for human cryptosporidiosis in the general US population are unknown. It has been suggested, but not documented, that physicians are generally unaware of the need to specifically request testing for this organism. OBJECTIVE: To assess physician awareness of cryptosporidiosis and knowledge of laboratory testing for Cryptosporidium oocysts. METHODS: A self-administered questionnaire was mailed to a stratified random sample of Connecticut physicians. Specialties were limited to physicians in internal medicine, gastroenterology, infectious disease, pediatrics, and family or general practice. Responses were compared among specialties. RESULTS: While most physicians were aware that cryptosporidiosis causes watery diarrhea (range, 67%-98%), particularly in patients with acquired immunodeficiency syndrome (> 85% of all specialties), many did not know the symptoms or failed to identify other groups at increased risk. More than 75% of gastroenterologists, general or family practitioners, internists, and pediatricians never or rarely order diagnostic testing for Cryptosporidium even when their patients have symptoms consistent with cryptosporidiosis. More than 30% of physicians assumed Cryptosporidium testing was included in a standard ova and parasite examination. CONCLUSIONS: Cryptosporidiosis is likely to be unrecognized and underdiagnosed in Connecticut. This may occur because many physicians are unaware of cryptosporidiosis, unsure of the symptoms, do not test for it, or do not order the appropriate test. Unless there is more widespread use of specific tests, it will be difficult to evaluate specific preventive initiatives to limit the overall health impact of cryptosporidiosis.

Factors influencing Cryptosporidium testing in Connecticut.

To describe patterns of testing for Cryptosporidium oocysts in stool samples, Connecticut laboratories were surveyed. Different detection methods were used. Most laboratories examined stools specifically for Cryptosporidium only on physician request. The rate of positive tests varted widely (0 to 28%). Higher rates of positivity were associated with the use of monoclonal antibody methods, the use of two or more staining procedures, and testing of stool specimens in addition to those requested by physicians.

Meat grinders and molecular epidemiology: two supermarket outbreaks of Escherichia coli O157:H7 infection.

Between 23 June and 15 July 1994, 21 cases (19 primary and 2 secondary) of Escherichia coli O157:H7 infection were identified in the Bethel, Connecticut, area. Three pulsed-field gel electrophoresis (PFGE) patterns from 15 isolates (I, n = 13; II, n = 2; and III, n = 1) were observed. A case-control study that excluded secondary cases and patients with PFGE II and III patterns (n = 16) demonstrated that consumption of food from one supermarket was associated with illness (15/16 cases vs. 31/47 geographically matched controls, odds ratio [OR] undefined, lower 95% confidence interval OR = 1.45, P = .018). No one food was associated with illness. Inspection of the supermarket revealed deficiencies in hygiene and meat handling practices. The 2 cases with PFGE II ate raw beef and raw lamb from a second supermarket. These outbreaks demonstrate the value of PFGE in supporting epidemiologic investigations and the potential for outbreaks arising from retail outlets.

The role of heightened surveillance in an outbreak of Escherichia coli O157.H7.

After instituting laboratory screening for Escherichia coli O157.H7, a Connecticut hospital isolated the organism from four persons in September 1993. As a result, an outbreak of E. coli O157.H7 associated with a country club was detected. The club had served hamburger from the same shipment at two picnics. Attendees of two picnics were interviewed, stool cultures were obtained from symptomatic persons, and the remaining hamburger was cultured. Twenty (22%) of 89 persons who ate hamburger became ill, compared with 1 of 60 who did not eat hamburger (relative risk = 13.5, 95% confidence interval 3.2-56.3). Among persons who ate hamburgers, illness was strongly associated with eating hamburger that was not thoroughly cooked (P < 0.001). All 20 samples from 5 remaining boxes of patties yielded E. coli O157.H7. Isolates from hamburger and case-patients were indistinguishable by pulsed-field gel electrophoresis. Heightened surveillance can rapidly identify outbreaks and may mitigate their impact. However, continued review of food safety issues is necessary if E. coli O157.H7 outbreaks are to be prevented.

Foodborne giardiasis in a corporate office setting.

Giardiasis is the most commonly reported intestinal protozoal infection worldwide, but its relatively long incubation period and often insidious onset make detection of common-source outbreaks difficult. Few well-documented foodborne outbreaks of giardiasis have been reported. In November 1990, such an outbreak among insurance company employees resulted in 18 laboratory-confirmed and 9 suspected cases of giardiasis. A case-control study of 26 ill and 162 well employees implicated raw sliced vegetables served in the employee cafeteria and prepared by a food handler infected with Giardia lamblia as the probable vehicle (odds ratio, 5.1; 95% confidence interval, 1.4-22.7). This outbreak illustrates the potential for transmission of Giardia organisms to occur in commercial establishments through a frequently served food item.

Incidence of listeriosis in Connecticut.

In Connecticut, 92 cases of human listeriosis were reported to the Department of Health Services from 1984 to 1988. The annual incidence per million population ranged from 7.3 in 1984 to 4.2 in 1988. The average annual incidence was 5.6 per million population. Case rates were highest in those aged 70 years and older (15.8 per million). Cases included 12 pregnant women and 11 newborns. Bacterial meningitis was the primary diagnosis in 23 cases. Of the 49 isolates of Listeria monocytogenes that were serotyped, 21 (43%) were type 4, 24 (49%) were type 1, and 4 (8%) were nontypable.

The epidemiology of Lyme disease in Connecticut.

The overall incidence for Lyme disease for Connecticut residents in 1988 was 22 per 100,000. The highest rates were among residents of New London (108 per 100,000) and Middlesex Counties (72 per 100,000), although the greatest increase in incidence between 1985 and 1988 occurred among residents of Fairfield County (2 per 100,000 in 1985, 14 per 100,000 in 1988). Lyme disease is a statewide problem; in 1988 cases were reported among residents of 104 of Connecticut's 169 towns and cities. The disease burden in some communities is high with case rates approaching 1% of the population per year. Data from 1977 and 1985 suggest a three- to eightfold increase during that period in the occurrence of Lyme disease in the communities near the mouth of the Connecticut River. Continued reporting of cases with supporting clinical information is needed to improve Lyme disease surveillance and establish disease trends.

Epidemiological and clinical features of 1,149 persons with Lyme disease identified by laboratory-based surveillance in Connecticut.

Laboratory-based surveillance of Lyme disease in Connecticut during 1984 and 1985 identified 3,098 persons with suspected Lyme disease; 1,149 were defined as cases. Lyme disease incidence in Connecticut towns ranged from none to 1,407 cases per 100,000 population in 1985. A comparison of 1985 data with data from 1977 epidemiologic studies indicated that incidence increased by 129 percent to 453 percent in towns previously known to be endemic for Lyme disease and that Lyme disease had spread northward into towns thought to be free of Lyme disease in 1977. Children aged five to 14 years had the highest incidence. Of persons with Lyme disease, 83 percent had erythema migrans, 24 percent had arthritis, 8 percent had neurologic sequelae, and 2 percent had cardiac sequelae. The distribution of symptoms was age-dependent: case-persons less than 20 years old were almost twice as likely to have arthritis than older case-persons (35 percent versus 18 percent). Of persons with arthritis, 92 percent of those less than 20 years of age, compared to 68 percent of older persons, did not have antecedent erythema migrans. We conclude that Lyme disease is increasing in incidence and geographic distribution in Connecticut. Of those with Lyme disease, children may be more likely than adults to develop arthritis and have it as their first major disease manifestation.